1
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Barman P, Ferdoush J, Kaja A, Chakraborty P, Uprety B, Bhaumik R, Bhaumik R, Bhaumik SR. Ubiquitin-proteasome system regulation of a key gene regulatory factor, Paf1C. Gene 2024; 894:148004. [PMID: 37977317 DOI: 10.1016/j.gene.2023.148004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 11/08/2023] [Accepted: 11/14/2023] [Indexed: 11/19/2023]
Abstract
Paf1 (Polymerase-associated factor 1) complex (Paf1C) is evolutionarily conserved from yeast to humans, and facilitates transcription elongation as well as co-transcriptional histone covalent modifications and mRNA 3'-end processing. Thus, Paf1C is a key player in regulation of eukaryotic gene expression. Paf1C consists of Paf1, Cdc73, Ctr9, Leo1 and Rtf1 in both yeast and humans, but it has an additional component, Ski8, in humans. The abundances of these components regulate the assembly of Paf1C and/or its functions, thus implying the mechanisms involved in regulating the abundances of the Paf1C components in altered gene expression and hence cellular pathologies. Towards finding the mechanisms associated with the abundances of the Paf1C components, we analyzed here whether the Paf1C components are regulated via targeted ubiquitylation and 26S proteasomal degradation. We find that the Paf1C components except Paf1 do not undergo the 26S proteasomal degradation in both yeast and humans. Paf1 is found to be regulated by the ubiquitin-proteasome system (UPS) in yeast and humans. Alteration of such regulation changes Paf1's abundance, leading to aberrant gene expression. Intriguingly, while the Rtf1 component of Paf1C does not undergo the 26S proteasomal degradation, it is found to be ubiquitylated, suggesting that Rtf1 ubiquitylation could be engaged in Paf1C assembly and/or functions. Collectively, our results reveal distinct UPS regulation of the Paf1C components, Paf1 and Rtf1, in a proteolysis-dependent and -independent manners, respectively, with functional implications.
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Affiliation(s)
- Priyanka Barman
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Jannatul Ferdoush
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Amala Kaja
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Pritam Chakraborty
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Bhawana Uprety
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Rhea Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Risa Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
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2
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Aoi Y, Shilatifard A. Transcriptional elongation control in developmental gene expression, aging, and disease. Mol Cell 2023; 83:3972-3999. [PMID: 37922911 DOI: 10.1016/j.molcel.2023.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/23/2023] [Accepted: 10/11/2023] [Indexed: 11/07/2023]
Abstract
The elongation stage of transcription by RNA polymerase II (RNA Pol II) is central to the regulation of gene expression in response to developmental and environmental cues in metazoan. Dysregulated transcriptional elongation has been associated with developmental defects as well as disease and aging processes. Decades of genetic and biochemical studies have painstakingly identified and characterized an ensemble of factors that regulate RNA Pol II elongation. This review summarizes recent findings taking advantage of genetic engineering techniques that probe functions of elongation factors in vivo. We propose a revised model of elongation control in this accelerating field by reconciling contradictory results from the earlier biochemical evidence and the recent in vivo studies. We discuss how elongation factors regulate promoter-proximal RNA Pol II pause release, transcriptional elongation rate and processivity, RNA Pol II stability and RNA processing, and how perturbation of these processes is associated with developmental disorders, neurodegenerative disease, cancer, and aging.
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Affiliation(s)
- Yuki Aoi
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ali Shilatifard
- Simpson Querrey Institute for Epigenetics, Department of Biochemistry and Molecular Genetics Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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3
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Liu X, Liu X, Du Y, Zou D, Tian C, Li Y, Lan X, David CJ, Sun Q, Chen M. Aberrant accumulation of Kras-dependent pervasive transcripts during tumor progression renders cancer cells dependent on PAF1 expression. Cell Rep 2023; 42:112979. [PMID: 37572321 DOI: 10.1016/j.celrep.2023.112979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 06/05/2023] [Accepted: 07/31/2023] [Indexed: 08/14/2023] Open
Abstract
KRAS is the most commonly mutated oncogene in human cancer, and mutant KRAS is responsible for over 90% of pancreatic ductal adenocarcinoma (PDAC), the most lethal cancer. Here, we show that RNA polymerase II-associated factor 1 complex (PAF1C) is specifically required for survival of PDAC but not normal adult pancreatic cells. We show that PAF1C maintains cancer cell genomic stability by restraining overaccumulation of enhancer RNAs (eRNAs) and promoter upstream transcripts (PROMPTs) driven by mutant Kras. Loss of PAF1C leads to cancer-specific lengthening and accumulation of pervasive transcripts on chromatin and concomitant aberrant R-loop formation and DNA damage, which, in turn, trigger cell death. We go on to demonstrate that the global transcriptional hyperactivation driven by Kras signaling during tumorigenesis underlies the specific demand for PAF1C by cancer cells. Our work provides insights into how enhancer transcription hyperactivation causes general transcription factor addiction during tumorigenesis.
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Affiliation(s)
- Xinhong Liu
- State Key Laboratory of Molecular Oncology, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Xiangzheng Liu
- State Key Laboratory of Molecular Oncology, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Yingxue Du
- Tsinghua University School of Life Sciences, Beijing 100084, China
| | - Di Zou
- State Key Laboratory of Molecular Oncology, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Chen Tian
- State Key Laboratory of Molecular Oncology, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Yong Li
- State Key Laboratory of Molecular Oncology, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Xun Lan
- State Key Laboratory of Molecular Oncology, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, School of Medicine, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Charles J David
- State Key Laboratory of Molecular Oncology, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, School of Medicine, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Qianwen Sun
- Tsinghua University School of Life Sciences, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Mo Chen
- State Key Laboratory of Molecular Oncology, SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, School of Medicine, Tsinghua University, Beijing 100084, China.
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4
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Li C, Guo Y, Wang L, Yan S. The SMC5/6 complex recruits the PAF1 complex to facilitate DNA double-strand break repair in Arabidopsis. EMBO J 2023; 42:e112756. [PMID: 36815434 PMCID: PMC10068331 DOI: 10.15252/embj.2022112756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/24/2023] Open
Abstract
DNA double-strand breaks (DSBs) are one of the most toxic forms of DNA damage, which threatens genome stability. Homologous recombination is an error-free DSB repair pathway, in which the evolutionarily conserved SMC5/6 complex (SMC5/6) plays essential roles. The PAF1 complex (PAF1C) is well known to regulate transcription. Here we show that SMC5/6 recruits PAF1C to facilitate DSB repair in plants. In a genetic screen for DNA damage response mutants (DDRMs), we found that the Arabidopsis ddrm4 mutant is hypersensitive to DSB-inducing agents and is defective in homologous recombination. DDRM4 encodes PAF1, a core subunit of PAF1C. Further biochemical and genetic studies reveal that SMC5/6 recruits PAF1C to DSB sites, where PAF1C further recruits the E2 ubiquitin-conjugating enzymes UBC1/2, which interact with the E3 ubiquitin ligases HUB1/2 to mediate the monoubiquitination of histone H2B at DSBs. These results implicate SMC5/6-PAF1C-UBC1/2-HUB1/2 as a new axis for DSB repair through homologous recombination, revealing a new mechanism of SMC5/6 and uncovering a novel function of PAF1C.
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Affiliation(s)
- Cunliang Li
- Hubei Hongshan LaboratoryWuhanChina
- College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen BranchGuangdong Laboratory for Lingnan Modern AgricultureShenzhenChina
- Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
| | - Yuyu Guo
- Hubei Hongshan LaboratoryWuhanChina
- College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen BranchGuangdong Laboratory for Lingnan Modern AgricultureShenzhenChina
- Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
| | - Lili Wang
- Hubei Hongshan LaboratoryWuhanChina
- College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen BranchGuangdong Laboratory for Lingnan Modern AgricultureShenzhenChina
- Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
| | - Shunping Yan
- Hubei Hongshan LaboratoryWuhanChina
- College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen BranchGuangdong Laboratory for Lingnan Modern AgricultureShenzhenChina
- Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
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5
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Jiang T, Wei F, Xie K. Clinical significance of pancreatic ductal metaplasia. J Pathol 2022; 257:125-139. [PMID: 35170758 DOI: 10.1002/path.5883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 02/06/2022] [Accepted: 02/14/2022] [Indexed: 11/08/2022]
Abstract
Pancreatic ductal metaplasia (PDM) is the stepwise replacement of differentiated somatic cells with ductal or ductal-like cells in the pancreas. PDM is usually triggered by cellular and environmental insults. PDM development may involve all cell lineages of the pancreas, and acinar cells with the highest plasticity are the major source of PDM. Pancreatic progenitor cells are also involved as cells of origin or transitional intermediates. PDM is heterogeneous at the histological, cellular, and molecular levels and only certain subsets of PDM develop further into pancreatic intraepithelial neoplasia (PanIN) and then pancreatic ductal adenocarcinoma (PDAC). The formation and evolution of PDM is regulated at the cellular and molecular levels through a complex network of signaling pathways. The key molecular mechanisms that drive PDM formation and its progression into PanIN/PDAC remain unclear, but represent key targets for reversing or inhibiting PDM. Alternatively, PDM could be a source of pancreas regeneration, including both exocrine and endocrine components. Cellular aging and apoptosis are obstacles to PDM-to-PanIN progression or pancreas regeneration. Functional identification of the cellular and molecular events driving senescence and apoptosis in PDM and its progression would help not only to restrict the development of PDM into PanIN/PDAC, but may also facilitate pancreatic regeneration. This review systematically assesses recent advances in the understanding of PDM physiology and pathology, with a focus on its implications for enhancing regeneration and prevention of cancer. © 2022 The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Tingting Jiang
- Center for Pancreatic Cancer Research, The South China University of Technology School of Medicine, Guangzhou, PR China
- Department of Pathology, The South China University of Technology School of Medicine, Guangzhou, PR China
| | - Fang Wei
- Institute of Digestive Diseases Research, The South China University of Technology School of Medicine, Guangzhou, PR China
| | - Keping Xie
- Center for Pancreatic Cancer Research, The South China University of Technology School of Medicine, Guangzhou, PR China
- Department of Pathology, The South China University of Technology School of Medicine, Guangzhou, PR China
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6
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Kubota Y, Ota N, Takatsuka H, Unno T, Onami S, Sugimoto A, Ito M. The
PAF1
complex cell‐autonomously promotes oogenesis in
Caenorhabditis elegans. Genes Cells 2022; 27:409-420. [PMID: 35430776 PMCID: PMC9321568 DOI: 10.1111/gtc.12938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/19/2022] [Accepted: 04/07/2022] [Indexed: 11/30/2022]
Abstract
The RNA polymerase II‐associated factor 1 complex (PAF1C) is a protein complex that consists of LEO1, RTF1, PAF1, CDC73, and CTR9, and has been shown to be involved in RNA polymerase II‐mediated transcriptional and chromatin regulation. Although it has been shown to regulate a variety of biological processes, the precise role of the PAF1C during germ line development has not been clarified. In this study, we found that reduction in the function of the PAF1C components, LEO‐1, RTFO‐1, PAFO‐1, CDC‐73, and CTR‐9, in Caenorhabditis elegans affects oogenesis. Defects in oogenesis were also confirmed using an oocyte maturation marker, OMA‐1::GFP. While four to five OMA‐1::GFP‐positive oocytes were observed in wild‐type animals, their numbers were significantly decreased in pafo‐1 mutant and leo‐1(RNAi), pafo‐1(RNAi), and cdc‐73(RNAi) animals. Expression of a functional PAFO‐1::mCherry transgene in the germline significantly rescued the oogenesis‐defective phenotype of the pafo‐1 mutants, suggesting that expression of the PAF1C in germ cells is required for oogenesis. Notably, overexpression of OMA‐1::GFP partially rescued the oogenesis defect in the pafo‐1 mutants. Based on our findings, we propose that the PAF1C promotes oogenesis in a cell‐autonomous manner by positively regulating the expression of genes involved in oocyte maturation.
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Affiliation(s)
- Yukihiro Kubota
- Department of Bioinformatics College of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
| | - Natsumi Ota
- Advanced Life Sciences Program Graduate School of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
| | - Hisashi Takatsuka
- Advanced Life Sciences Program Graduate School of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
| | - Takuma Unno
- Advanced Life Sciences Program Graduate School of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
| | - Shuichi Onami
- Advanced Life Sciences Program Graduate School of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
- RIKEN Center for Biosystems Dynamics Research 2‐2‐3, Minatojima‐minamimachi, Chuo‐ku Kobe Japan
| | - Asako Sugimoto
- Laboratory of Developmental Dinamics Graduate School of Life Sciences, Tohoku University 2‐1‐1 Katahira Sendai Miyagi Japan
| | - Masahiro Ito
- Department of Bioinformatics College of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
- Advanced Life Sciences Program Graduate School of Life Sciences, Ritsumeikan University 1‐1‐1 Nojihigashi Kusatsu Shiga Japan
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7
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Paul S, Balakrishnan S, Arumugaperumal A, Lathakumari S, Syamala SS, Vijayan V, Durairaj SCJ, Arumugaswami V, Sivasubramaniam S. Importance of clitellar tissue in the regeneration ability of earthworm Eudrilus eugeniae. Funct Integr Genomics 2022; 22:1-32. [PMID: 35416560 DOI: 10.1007/s10142-022-00849-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 11/04/2022]
Abstract
Among the annelids, earthworms are renowned for their phenomenal ability to regenerate the lost segments. The adult earthworm Eudrilus eugeniae contains 120 segments and the body segments of the earthworm are divided into pre-clitellar, clitellar and post-clitellar segments. The present study denoted that clitellum plays vital role in the successful regeneration of the species. We have performed histological studies to identify among the three skin layers of the earthworm, which cellular layer supports the blastema formation and regeneration of the species. The histological evidences denoted that the proliferation of the longitudinal cell layer at the amputation site is crucial for the successful regeneration of the earthworm and it takes place only in the presence of an intact clitellum. Besides we have performed clitellar transcriptome analysis of the earthworm Eudrilus eugeniae to monitor the key differentially expressed genes and their associated functions and pathways controlling the clitellar tissue changes during both anterior and posterior regeneration of the earthworm. A total of 4707 differentially expressed genes (DEGs) were identified between the control clitellum and clitellum of anterior regenerated earthworms and 4343 DEGs were detected between the control clitellum and clitellum of posterior regenerated earthworms. The functional enrichment analysis confirmed the genes regulating the muscle mass shape and structure were significantly downregulated and the genes associated with response to starvation and anterior-posterior axis specification were significantly upregulated in the clitellar tissue during both anterior and posterior regeneration of the earthworm. The RNA sequencing data of clitellum and the comparative transcriptomic analysis were helpful to understand the complex regeneration process of the earthworm.
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Affiliation(s)
- Sayan Paul
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India.,Centre for Cardiovascular Biology and Disease, Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, 560065, India
| | | | - Arun Arumugaperumal
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India
| | - Saranya Lathakumari
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India
| | - Sandhya Soman Syamala
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India
| | - Vijithkumar Vijayan
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India
| | - Selvan Christyraj Jackson Durairaj
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India.,Centre for Nanoscience and Nanotechnology, Sathyabama Institute of Science and Technology, Chennai, Tamilnadu, 600 119, India
| | | | - Sudhakar Sivasubramaniam
- Department of Biotechnology, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, 627012, India.
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8
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Chen F, Liu B, Zeng J, Guo L, Ge X, Feng W, Li DF, Zhou H, Long J. Crystal Structure of the Core Module of the Yeast Paf1 Complex. J Mol Biol 2021; 434:167369. [PMID: 34852272 DOI: 10.1016/j.jmb.2021.167369] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/08/2021] [Accepted: 11/12/2021] [Indexed: 12/31/2022]
Abstract
The highly conserved multifunctional polymerase-associated factor 1 (Paf1) complex (PAF1C), which consists of five core subunits: Ctr9, Paf1, Leo1, Cdc73, and Rtf1, acts as a diverse hub that regulates all stages of RNA polymerase II-mediated transcription and various other cellular functions. However, the underlying mechanisms remain unclear. Here, we report the crystal structure of the core module derived from a quaternary Ctr9/Paf1/Cdc73/Rtf1 complex of S. cerevisiae PAF1C, which reveals interfaces between the tetratricopeptide repeat module in Ctr9 and Cdc73 or Rtf1, and find that the Ctr9/Paf1 subcomplex is the key scaffold for PAF1C assembly. Our study demonstrates that Cdc73 binds Ctr9/Paf1 subcomplex with a very similar conformation within thermophilic fungi or human PAF1C, and that the binding of Cdc73 to PAF1C is important for yeast growth. Importantly, our structure reveals for the first time that the extreme C-terminus of Rtf1 adopts an "L"-shaped structure, which interacts with Ctr9 specifically. In addition, disruption of the binding of either Cdc73 or Rtf1 to PAF1C greatly affects the normal level of histone H2B K123 monoubiquitination in vivo. Collectively, our results provide a structural insight into the architecture of the quaternary Ctr9/Paf1/Cdc73/Rtf1 complex and PAF1C functional regulation.
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Affiliation(s)
- Feilong Chen
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Beibei Liu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Jianwei Zeng
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lu Guo
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xuan Ge
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Feng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - De-Feng Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Hao Zhou
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
| | - Jiafu Long
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China; Nankai International Advanced Research Institute (Shenzhen Futian), Shenzhen, Guangdong 518045, China.
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9
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Transcription recycling assays identify PAF1 as a driver for RNA Pol II recycling. Nat Commun 2021; 12:6318. [PMID: 34732721 PMCID: PMC8566496 DOI: 10.1038/s41467-021-26604-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 10/17/2021] [Indexed: 11/20/2022] Open
Abstract
RNA Polymerase II (Pol II) transcriptional recycling is a mechanism for which the required factors and contributions to overall gene expression levels are poorly understood. We describe an in vitro methodology facilitating unbiased identification of putative RNA Pol II transcriptional recycling factors and quantitative measurement of transcriptional output from recycled transcriptional components. Proof-of-principle experiments identified PAF1 complex components among recycling factors and detected defective transcriptional output from Pol II recycling following PAF1 depletion. Dynamic ChIP-seq confirmed PAF1 silencing triggered defective Pol II recycling in human cells. Prostate tumors exhibited enhanced transcriptional recycling, which was attenuated by antibody-based PAF1 depletion. These findings identify Pol II recycling as a potential target in cancer and demonstrate the applicability of in vitro and cellular transcription assays to characterize Pol II recycling in other disease states. RNA Polymerase II (Pol II) recycling can influence transcription efficiency. Here the authors describe an approach aimed at facilitating the identification of factors involved in Pol II recycling and identify PAF1 complex components as mediators of recycling.
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10
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Fischer J, Ardakani FB, Kattler K, Walter J, Schulz MH. CpG content-dependent associations between transcription factors and histone modifications. PLoS One 2021; 16:e0249985. [PMID: 33857234 PMCID: PMC8049299 DOI: 10.1371/journal.pone.0249985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/30/2021] [Indexed: 11/18/2022] Open
Abstract
Understanding the factors that underlie the epigenetic regulation of genes is crucial to understand the gene regulatory machinery as a whole. Several experimental and computational studies examined the relationship between different factors involved. Here we investigate the relationship between transcription factors (TFs) and histone modifications (HMs), based on ChIP-seq data in cell lines. As it was shown that gene regulation by TFs differs depending on the CpG class of a promoter, we study the impact of the CpG content in promoters on the associations between TFs and HMs. We suggest an approach based on sparse linear regression models to infer associations between TFs and HMs with respect to CpG content. A study of the partial correlation of HMs for the two classes of high and low CpG content reveals possible CpG dependence and potential candidates for confounding factors in our models. We show that the models are accurate, inferred associations reflect known biological relationships, and we give new insight into associations with respect to CpG content. Moreover, analysis of a ChIP-seq dataset in HepG2 cells of the HM H3K122ac, an HM about little is known, reveals novel TF associations and supports a previously established link to active transcription.
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Affiliation(s)
- Jonas Fischer
- Max Planck Institute for Informatics, Databases and Information Systems, Saarbrücken, Germany
- Cluster of Excellence for Multimodal Computing and Interaction, High Throughput Genomics and Systems Biology, Saarbrücken, Germany
- * E-mail:
| | - Fatemeh Behjati Ardakani
- Max Planck Institute for Informatics, Computational Biology and Applied Algorithmics, Saarbrücken, Germany
- Cluster of Excellence for Multimodal Computing and Interaction, High Throughput Genomics and Systems Biology, Saarbrücken, Germany
- Institute of Cardiovascular Regeneration, Goethe University, Frankfurt, Germany
| | - Kathrin Kattler
- Department of Genetics, University of Saarland, Saarbrücken, Germany
| | - Jörn Walter
- Department of Genetics, University of Saarland, Saarbrücken, Germany
| | - Marcel H. Schulz
- Max Planck Institute for Informatics, Computational Biology and Applied Algorithmics, Saarbrücken, Germany
- Cluster of Excellence for Multimodal Computing and Interaction, High Throughput Genomics and Systems Biology, Saarbrücken, Germany
- Institute of Cardiovascular Regeneration, Goethe University, Frankfurt, Germany
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11
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Wang L, Xiong X, Yao Z, Zhu J, Lin Y, Lin W, Li K, Xu X, Guo Y, Chen Y, Pan Y, Zhou F, Fan J, Chen Y, Gao S, Jim Yeung SC, Zhang H. Chimeric RNA ASTN2-PAPPA as aggravates tumor progression and metastasis in human esophageal cancer. Cancer Lett 2021; 501:1-11. [PMID: 33388371 DOI: 10.1016/j.canlet.2020.10.052] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/26/2020] [Accepted: 10/29/2020] [Indexed: 02/05/2023]
Abstract
Transcription-induced chimeric RNAs are an emerging area of research into molecular signatures for disease biomarker and therapeutic target development. Despite their importance, little is known for chimeric RNAs-relevant roles and the underlying mechanisms for cancer pathogenesis and progression. Here we describe a unique ASTN2-PAPPAantisense chimeric RNA (A-PaschiRNA) that could be the first reported chimeric RNA derived from the splicing of exons and intron antisense of two neighboring genes, respectively. Aberrant A-PaschiRNA level in ESCC tissues was associated with tumor progression and patients' outcome. In vitro and in vivo studies demonstrated that A-PaschiRNA aggravated ESCC metastasis and enhanced stemness through modulating OCT4. Mechanistic studies demonstrated that ERK5-mediated non-canonical PAF1 activity was required for A-PaschiRNA-induced cancer malignancy. The study defined an undocumented function of chimeric RNAs in aggravating cancer stemness and metastasis.
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Affiliation(s)
- Lu Wang
- Department of General Surgery, The First Affiliated Hospital of Jinan University, Institute of Precision Cancer Medicine and Pathology, School of Medicine, Jinan University, Guangzhou, Guangdong, China
| | - Xiao Xiong
- Department of General Surgery, The First Affiliated Hospital of Jinan University, Institute of Precision Cancer Medicine and Pathology, School of Medicine, Jinan University, Guangzhou, Guangdong, China
| | - Zhimeng Yao
- Department of General Surgery, The First Affiliated Hospital of Jinan University, Institute of Precision Cancer Medicine and Pathology, School of Medicine, Jinan University, Guangzhou, Guangdong, China
| | - Jianlin Zhu
- Department of General Surgery, The First Affiliated Hospital of Jinan University, Institute of Precision Cancer Medicine and Pathology, School of Medicine, Jinan University, Guangzhou, Guangdong, China
| | - Yusheng Lin
- Department of General Surgery, The First Affiliated Hospital of Jinan University, Institute of Precision Cancer Medicine and Pathology, School of Medicine, Jinan University, Guangzhou, Guangdong, China; Department of Hematology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Wan Lin
- Cancer Research Center, Shantou University Medical College, Shantou, Guangdong, 515041, China
| | - Kai Li
- Department of General Surgery, The First Affiliated Hospital of Jinan University, Institute of Precision Cancer Medicine and Pathology, School of Medicine, Jinan University, Guangzhou, Guangdong, China
| | - Xiaozheng Xu
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Yi Guo
- Endoscopy Center, Affiliated Cancer Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Yuping Chen
- Department of Thoracic Surgery, Affiliated Cancer Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Yunlong Pan
- Department of General Surgery, The First Affiliated Hospital of Jinan University, Institute of Precision Cancer Medicine and Pathology, School of Medicine, Jinan University, Guangzhou, Guangdong, China
| | - Fuyou Zhou
- The Fourth Affiliated Hospital of Henan University of Science and Technology, Anyang, Henan, 455001, China; Department of Thoracic Surgery, Anyang Tumor Hospital, Anyang, Henan, 455001, China
| | - Jun Fan
- Department of Medical Biochemistry and Molecular Biology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Yan Chen
- Department of Medical Biochemistry and Molecular Biology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Shegan Gao
- College of Clinical Medicine, The First Affiliated Hospital of Henan University of Science and Technology, Henan Key Laboratory of Cancer Epigenetics, Luoyang, 471003, China.
| | - Sai-Ching Jim Yeung
- Department of Emergency Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA; Department of Endocrine Neoplasia and Hormonal Disorders, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Hao Zhang
- Department of General Surgery, The First Affiliated Hospital of Jinan University, Institute of Precision Cancer Medicine and Pathology, School of Medicine, Jinan University, Guangzhou, Guangdong, China.
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12
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Petralia F, Tignor N, Reva B, Koptyra M, Chowdhury S, Rykunov D, Krek A, Ma W, Zhu Y, Ji J, Calinawan A, Whiteaker JR, Colaprico A, Stathias V, Omelchenko T, Song X, Raman P, Guo Y, Brown MA, Ivey RG, Szpyt J, Guha Thakurta S, Gritsenko MA, Weitz KK, Lopez G, Kalayci S, Gümüş ZH, Yoo S, da Veiga Leprevost F, Chang HY, Krug K, Katsnelson L, Wang Y, Kennedy JJ, Voytovich UJ, Zhao L, Gaonkar KS, Ennis BM, Zhang B, Baubet V, Tauhid L, Lilly JV, Mason JL, Farrow B, Young N, Leary S, Moon J, Petyuk VA, Nazarian J, Adappa ND, Palmer JN, Lober RM, Rivero-Hinojosa S, Wang LB, Wang JM, Broberg M, Chu RK, Moore RJ, Monroe ME, Zhao R, Smith RD, Zhu J, Robles AI, Mesri M, Boja E, Hiltke T, Rodriguez H, Zhang B, Schadt EE, Mani DR, Ding L, Iavarone A, Wiznerowicz M, Schürer S, Chen XS, Heath AP, Rokita JL, Nesvizhskii AI, Fenyö D, Rodland KD, Liu T, Gygi SP, Paulovich AG, Resnick AC, Storm PB, Rood BR, Wang P. Integrated Proteogenomic Characterization across Major Histological Types of Pediatric Brain Cancer. Cell 2020; 183:1962-1985.e31. [PMID: 33242424 PMCID: PMC8143193 DOI: 10.1016/j.cell.2020.10.044] [Citation(s) in RCA: 154] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/19/2020] [Accepted: 10/26/2020] [Indexed: 02/06/2023]
Abstract
We report a comprehensive proteogenomics analysis, including whole-genome sequencing, RNA sequencing, and proteomics and phosphoproteomics profiling, of 218 tumors across 7 histological types of childhood brain cancer: low-grade glioma (n = 93), ependymoma (32), high-grade glioma (25), medulloblastoma (22), ganglioglioma (18), craniopharyngioma (16), and atypical teratoid rhabdoid tumor (12). Proteomics data identify common biological themes that span histological boundaries, suggesting that treatments used for one histological type may be applied effectively to other tumors sharing similar proteomics features. Immune landscape characterization reveals diverse tumor microenvironments across and within diagnoses. Proteomics data further reveal functional effects of somatic mutations and copy number variations (CNVs) not evident in transcriptomics data. Kinase-substrate association and co-expression network analysis identify important biological mechanisms of tumorigenesis. This is the first large-scale proteogenomics analysis across traditional histological boundaries to uncover foundational pediatric brain tumor biology and inform rational treatment selection.
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Affiliation(s)
- Francesca Petralia
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Nicole Tignor
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Boris Reva
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Mateusz Koptyra
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Shrabanti Chowdhury
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Dmitry Rykunov
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Azra Krek
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Weiping Ma
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yuankun Zhu
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jiayi Ji
- Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Anna Calinawan
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | | | - Antonio Colaprico
- Department of Public Health Science, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Vasileios Stathias
- Department of Pharmacology, Institute for Data Science and Computing, Sylvester Comprehensive Cancer Center, University of Miami, Miami, FL 33146, USA
| | - Tatiana Omelchenko
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Xiaoyu Song
- Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Pichai Raman
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Bioinformatics and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yiran Guo
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Miguel A Brown
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Richard G Ivey
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - John Szpyt
- Thermo Fisher Scientific Center for Multiplexed Proteomics, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Sanjukta Guha Thakurta
- Thermo Fisher Scientific Center for Multiplexed Proteomics, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Marina A Gritsenko
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Karl K Weitz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Gonzalo Lopez
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Selim Kalayci
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Zeynep H Gümüş
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Seungyeul Yoo
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | | | - Hui-Yin Chang
- Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Karsten Krug
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02412, USA
| | - Lizabeth Katsnelson
- Institute for Systems Genetics; Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Ying Wang
- Institute for Systems Genetics; Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Jacob J Kennedy
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | | | - Lei Zhao
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Krutika S Gaonkar
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Bioinformatics and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Brian M Ennis
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Bo Zhang
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Valerie Baubet
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Lamiya Tauhid
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jena V Lilly
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jennifer L Mason
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Bailey Farrow
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nathan Young
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sarah Leary
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Cancer and Blood Disorders Center, Seattle Children's Hospital, Seattle, WA 98105, USA; Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Jamie Moon
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Vladislav A Petyuk
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Javad Nazarian
- Children's National Research Institute, George Washington University School of Medicine, Washington, DC 20010, USA; Department of Oncology, Children's Research Center, University Children's Hospital Zürich, Zürich 8032, Switzerland
| | - Nithin D Adappa
- Department of Otorhinolaryngology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James N Palmer
- Department of Otorhinolaryngology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert M Lober
- Department of Neurosurgery, Dayton Children's Hospital, Dayton, OH 45404, USA
| | - Samuel Rivero-Hinojosa
- Children's National Research Institute, George Washington University School of Medicine, Washington, DC 20010, USA
| | - Liang-Bo Wang
- Department of Medicine, Washington University in St. Louis, St. Louis, MO 631110, USA; McDonnell Genome Institute, Washington University in St. Louis, St. Louis, MO 63108, USA
| | - Joshua M Wang
- Institute for Systems Genetics; Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Matilda Broberg
- Institute for Systems Genetics; Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Rosalie K Chu
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Ronald J Moore
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Matthew E Monroe
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Rui Zhao
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Richard D Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Jun Zhu
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ana I Robles
- Office of Cancer Clinical Proteomics Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mehdi Mesri
- Office of Cancer Clinical Proteomics Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Emily Boja
- Office of Cancer Clinical Proteomics Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tara Hiltke
- Office of Cancer Clinical Proteomics Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Henry Rodriguez
- Office of Cancer Clinical Proteomics Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bing Zhang
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Eric E Schadt
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - D R Mani
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02412, USA
| | - Li Ding
- Department of Medicine, Washington University in St. Louis, St. Louis, MO 631110, USA; McDonnell Genome Institute, Washington University in St. Louis, St. Louis, MO 63108, USA; Siteman Cancer Center, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Antonio Iavarone
- Institute for Cancer Genetics, Department of Neurology, Department of Pathology and Cell Biology, Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
| | - Maciej Wiznerowicz
- Poznan University of Medical Sciences, 61-701 Poznań, Poland; International Institute for Molecular Oncology, 61-203 Poznań, Poland
| | - Stephan Schürer
- Department of Pharmacology, Institute for Data Science and Computing, Sylvester Comprehensive Cancer Center, University of Miami, Miami, FL 33146, USA
| | - Xi S Chen
- Department of Public Health Science, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Allison P Heath
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jo Lynne Rokita
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Bioinformatics and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Alexey I Nesvizhskii
- Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Computational Medicine & Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - David Fenyö
- Institute for Systems Genetics; Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Karin D Rodland
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA; Department of Cell, Developmental, and Cancer Biology, Oregon Health & Science University, Portland, OR 97221, USA
| | - Tao Liu
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Steven P Gygi
- Thermo Fisher Scientific Center for Multiplexed Proteomics, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | | | - Adam C Resnick
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
| | - Phillip B Storm
- Center for Data-Driven Discovery in Biomedicine, Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
| | - Brian R Rood
- Children's National Research Institute, George Washington University School of Medicine, Washington, DC 20010, USA.
| | - Pei Wang
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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13
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Karmakar S, Rauth S, Nallasamy P, Perumal N, Nimmakalaya RK, Leon F, Gupta R, Barkeer S, Venkata RC, Raman V, Rachagani S, Ponnusamy MP, Batra SK. RNA Polymerase II-Associated Factor 1 Regulates Stem Cell Features of Pancreatic Cancer Cells, Independently of the PAF1 Complex, via Interactions With PHF5A and DDX3. Gastroenterology 2020; 159:1898-1915.e6. [PMID: 32781084 PMCID: PMC7680365 DOI: 10.1053/j.gastro.2020.07.053] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 07/13/2020] [Accepted: 07/28/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS It is not clear how pancreatic cancer stem cells (CSCs) are regulated, resulting in ineffective treatments for pancreatic cancer. PAF1, a RNA polymerase II-associated factor 1 complex (PAF1C) component, maintains pluripotency of stem cells, by unclear mechanisms, and is a marker of CSCs. We investigated mechanisms by which PAF1 maintains CSCs and contributes to development of pancreatic tumors. METHODS Pancreatic cancer cell lines were engineered to knockdown PAF1 using inducible small hairpin RNAs. These cells were grown as orthotopic tumors in athymic nude mice and PAF1 knockdown was induced by administration of doxycycline in drinking water. Tumor growth and metastasis were monitored via IVIS imaging. CSCs were isolated from pancreatic cancer cell populations using flow cytometry and characterized by tumor sphere formation, tumor formation in nude mice, and expression of CSC markers. Isolated CSCs were depleted of PAF1 using the CRISPR/Cas9 system. PAF1-regulated genes in CSCs were identified via RNA-seq and PCR array analyses of cells with PAF1 knockdown. Proteins that interact with PAF1 in CSCs were identified by immunoprecipitations and mass spectrometry. We performed chromatin immunoprecipitation sequencing of CSCs to confirm the binding of the PAF1 sub-complex to target genes. RESULTS Pancreatic cancer cells depleted of PAF1 formed smaller and fewer tumor spheres in culture and orthotopic tumors and metastases in mice. Isolated CSCs depleted of PAF1 downregulated markers of self-renewal (NANOG, SOX9, and β-CATENIN), of CSCs (CD44v6, and ALDH1), and the metastasis-associated gene signature, compared to CSCs without knockdown of PAF1. The role of PAF1 in CSC maintenance was independent of its RNA polymerase II-associated factor 1 complex component identity. We identified DDX3 and PHF5A as proteins that interact with PAF1 in CSCs and demonstrated that the PAF1-PHF5A-DDX3 sub-complex bound to the promoter region of Nanog, whose product regulates genes that control stemness. Levels of the PAF1-DDX3 and PAF1-PHF5A were increased and co-localized in human pancreatic tumor specimens, human pancreatic tumor-derived organoids, and organoids derived from tumors of KPC mice, compared with controls. Binding of DDX3 and PAF1 to the Nanog promoter, and the self-renewal capacity of CSCs, were decreased in cells incubated with the DDX3 inhibitor RK-33. CSCs depleted of PAF1 downregulated genes that regulate stem cell features (Flot2, Taz, Epcam, Erbb2, Foxp1, Abcc5, Ddr1, Muc1, Pecam1, Notch3, Aldh1a3, Foxa2, Plat, and Lif). CONCLUSIONS In pancreatic CSCs, PAF1 interacts with DDX3 and PHF5A to regulate expression of NANOG and other genes that regulate stemness. Knockdown of PAF1 reduces the ability of orthotopic pancreatic tumors to develop and progress in mice and their numbers of CSCs. Strategies to target the PAF1-PHF5A-DDX3 complex might be developed to slow or inhibit progression of pancreatic cancer.
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Affiliation(s)
- Saswati Karmakar
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Sanchita Rauth
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Palanisamy Nallasamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Naveenkumar Perumal
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Rama Krishna Nimmakalaya
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Frank Leon
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Rohitesh Gupta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Srikanth Barkeer
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | | | - Venu Raman
- Departments of Radiology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, U.S.A
| | - Satyanarayana Rachagani
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Moorthy P. Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A.,Eppley Institute for Research in Cancer and Allied Diseases and Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, U.S.A.,Correspondence: Surinder K. Batra, Ph.D., or Moorthy P. Ponnusamy, Ph.D. Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5870, U.S.A. Phone: 402-559-5455, Fax: 402-559-6650, or
| | - Surinder K. Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A.,Eppley Institute for Research in Cancer and Allied Diseases and Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, U.S.A.,Correspondence: Surinder K. Batra, Ph.D., or Moorthy P. Ponnusamy, Ph.D. Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5870, U.S.A. Phone: 402-559-5455, Fax: 402-559-6650, or
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14
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Zheng JJ, He Y, Liu Y, Li FS, Cui Z, Du XM, Wang CP, Wu YM. Novel role of PAF1 in attenuating radiosensitivity in cervical cancer by inhibiting IER5 transcription. Radiat Oncol 2020; 15:131. [PMID: 32471508 PMCID: PMC7257241 DOI: 10.1186/s13014-020-01580-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 05/20/2020] [Indexed: 01/16/2023] Open
Abstract
Background Radiosensitivity is limited in cervical cancer (CC) patients due to acquired radiation resistance. In our previous studies, we found that immediate-early response 5 (IER5) is upregulated in CC cells upon radiation exposure and decreases cell survival by promoting apoptosis. The details on the transcriptional regulation of radiation-induced IER5 expression are unknown. Studies in recent years have suggested that Pol II-associated factor 1 (PAF1) is a pivotal transcription factor for certain genes “induced” during tumor progression. In this study, we investigated the role of PAF1 in regulating IER5 expression during CC radiotherapy. Methods PAF1 expression in CC cells was measured by western blotting, immunohistochemistry, and qRT-PCR, and the localization of PAF1 and IER5 was determined by immunofluorescence. The effect of PAF1 and IER5 knockdown by siRNA in Siha and Hela cells was studied by western blotting, qRT-PCR, CCK-8 assay, and flow cytometry. The physical interaction of PAF1 with the IER5 promoter and enhancers was confirmed using chromatin immunoprecipitation and qPCR with or without enhancers knockout by CRISPR/Cas9. Results We confirmed that PAF1 was highly expressed in CC cells and that relatively low expression of IER5 was observed in cells with highly expressed PAF1 in the nucleus. PAF1 knockdown in Siha and Hela cells was associated with increased expression of IER5, reduced cell viability and higher apoptosis rate in response to radiation exposure, while simultaneous PAF1 and IER5 knockdown had little effect on the proportion of apoptotic cells. We also found that PAF1 hindered the transcription of IER5 by promoting Pol II pausing at the promoter-proximal region, which was primarily due to the binding of PAF1 at the enhancers. Conclusions PAF1 reduces CC radiosensitivity by inhibiting IER5 transcription, at least in part by regulating its enhancers. PAF1 might be a potential therapeutic target for overcoming radiation resistance in CC patients.
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Affiliation(s)
- Jing-Jie Zheng
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Present address: Dong-Cheng District, Qi-He-Lou Street No.17, Beijing, 100006, China
| | - Yue He
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Present address: Dong-Cheng District, Qi-He-Lou Street No.17, Beijing, 100006, China
| | - Yang Liu
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Present address: Dong-Cheng District, Qi-He-Lou Street No.17, Beijing, 100006, China
| | - Feng-Shuang Li
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Present address: Dong-Cheng District, Qi-He-Lou Street No.17, Beijing, 100006, China
| | - Zhen Cui
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Present address: Dong-Cheng District, Qi-He-Lou Street No.17, Beijing, 100006, China
| | - Xiao-Meng Du
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Present address: Dong-Cheng District, Qi-He-Lou Street No.17, Beijing, 100006, China
| | - Chun-Peng Wang
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Present address: Dong-Cheng District, Qi-He-Lou Street No.17, Beijing, 100006, China
| | - Yu-Mei Wu
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Present address: Dong-Cheng District, Qi-He-Lou Street No.17, Beijing, 100006, China.
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15
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The PAF1c Subunit CDC73 Is Required for Mouse Hematopoietic Stem Cell Maintenance but Displays Leukemia-Specific Gene Regulation. Stem Cell Reports 2019; 12:1069-1083. [PMID: 31031188 PMCID: PMC6524170 DOI: 10.1016/j.stemcr.2019.03.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 12/21/2022] Open
Abstract
The Polymerase Associated Factor 1 complex (PAF1c) functions at the interface of epigenetics and gene transcription. The PAF1c is required for MLL fusion-driven acute myeloid leukemia (AML) through direct regulation of pro-leukemic target genes such as Hoxa9 and Meis1. However, the role of the PAF1c in normal hematopoiesis is unknown. Here, we discovered that the PAF1c subunit, CDC73, is required for both fetal and adult hematopoiesis. Loss of Cdc73 in hematopoietic cells is lethal because of extensive bone marrow failure. Cdc73 has an essential cell-autonomous role for adult hematopoietic stem cell function in vivo, and deletion of Cdc73 results in cell-cycle defects in hematopoietic progenitors. Gene expression profiling indicated a differential regulation of Hoxa9/Meis1 gene programs by CDC73 in progenitors compared with AML cells, suggesting disease-specific functions. Thus, the PAF1c subunit, CDC73 is essential for hematopoietic stem cell function but exhibits leukemia-specific regulation of self-renewal gene programs in AML cells. CDC73 is necessary for embryonic and adult hematopoietic stem cell function Proliferation and survival of cKIT+ hematopoietic progenitors require CDC73 CDC73 regulates unique gene programs in leukemia and hematopoietic progenitor cells
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16
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A peptide encoded by circular form of LINC-PINT suppresses oncogenic transcriptional elongation in glioblastoma. Nat Commun 2018; 9:4475. [PMID: 30367041 PMCID: PMC6203777 DOI: 10.1038/s41467-018-06862-2] [Citation(s) in RCA: 443] [Impact Index Per Article: 73.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 10/02/2018] [Indexed: 01/12/2023] Open
Abstract
Circular RNAs (circRNAs) are a large class of transcripts in the mammalian genome. Although the translation of circRNAs was reported, additional coding circRNAs and the functions of their translated products remain elusive. Here, we demonstrate that an endogenous circRNA generated from a long noncoding RNA encodes regulatory peptides. Through ribosome nascent-chain complex-bound RNA sequencing (RNC-seq), we discover several peptides potentially encoded by circRNAs. We identify an 87-amino-acid peptide encoded by the circular form of the long intergenic non-protein-coding RNA p53-induced transcript (LINC-PINT) that suppresses glioblastoma cell proliferation in vitro and in vivo. This peptide directly interacts with polymerase associated factor complex (PAF1c) and inhibits the transcriptional elongation of multiple oncogenes. The expression of this peptide and its corresponding circRNA are decreased in glioblastoma compared with the levels in normal tissues. Our results establish the existence of peptides encoded by circRNAs and demonstrate their potential functions in glioblastoma tumorigenesis. Functional peptides can be encoded by short open reading frames in non-coding RNA. Here, the authors identify a 87aa peptide encoded by the circular form of the long intergenic non-protein-coding RNA p53-induced transcript (LINC-PINT) that can reduce glioblastoma proliferation via interaction with PAF1 which sequentially inhibits the transcriptional elongation of some oncogenes.
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17
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Paf1 and Ctr9 subcomplex formation is essential for Paf1 complex assembly and functional regulation. Nat Commun 2018; 9:3795. [PMID: 30228257 PMCID: PMC6143631 DOI: 10.1038/s41467-018-06237-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 08/15/2018] [Indexed: 11/09/2022] Open
Abstract
The evolutionarily conserved multifunctional polymerase-associated factor 1 (Paf1) complex (Paf1C), which is composed of at least five subunits (Paf1, Leo1, Ctr9, Cdc73, and Rtf1), plays vital roles in gene regulation and has connections to development and human diseases. Here, we report two structures of each of the human and yeast Ctr9/Paf1 subcomplexes, which assemble into heterodimers with very similar conformations, revealing an interface between the tetratricopeptide repeat module in Ctr9 and Paf1. The structure of the Ctr9/Paf1 subcomplex may provide mechanistic explanations for disease-associated mutations in human PAF1 and CTR9. Our study reveals that the formation of the Ctr9/Paf1 heterodimer is required for the assembly of yeast Paf1C, and is essential for yeast viability. In addition, disruption of the interaction between Paf1 and Ctr9 greatly affects the level of histone H3 methylation in vivo. Collectively, our results shed light on Paf1C assembly and functional regulation.
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18
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Nimmakayala RK, Seshacharyulu P, Lakshmanan I, Rachagani S, Chugh S, Karmakar S, Rauth S, Vengoji R, Atri P, Talmon GA, Lele SM, Smith LM, Thapa I, Bastola D, Ouellette MM, Batra SK, Ponnusamy MP. Cigarette Smoke Induces Stem Cell Features of Pancreatic Cancer Cells via PAF1. Gastroenterology 2018; 155:892-908.e6. [PMID: 29864419 PMCID: PMC6120776 DOI: 10.1053/j.gastro.2018.05.041] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 05/08/2018] [Accepted: 05/30/2018] [Indexed: 12/15/2022]
Abstract
BACKGROUND & AIMS Cigarette smoking is a major risk factor for pancreatic cancer. Aggressive pancreatic tumors contain cancer cells with stem cell features. We investigated whether cigarette smoke induces stem cell features in pancreatic cancer cells. METHODS KrasG12D; Pdx1-Cre mice were exposed to cigarette smoke or clean air (controls) for up to 20 weeks; pancreata were collected and analyzed by histology, quantitative reverse transcription polymerase chain reaction, and confocal immunofluorescence microscopy. HPNE and Capan1 cells were exposed to cigarette smoke extract (CSE), nicotine and nicotine-derived carcinogens (NNN or NNK), or clean air (controls) for 80 days and evaluated for stem cell markers and features using flow cytometry-based autofluorescence, sphere formation, and immunoblot assays. Proteins were knocked down in cells with small interfering RNAs. We performed RNA sequencing analyses of CSE-exposed cells. We used chromatin immunoprecipitation assays to confirm the binding of FOS-like 1, AP-1 transcription factor subunit (FOSL1) to RNA polymerase II-associated factor (PAF1) promoter. We obtained pancreatic ductal adenocarcinoma (PDAC) and matched nontumor tissues (n = 15) and performed immunohistochemical analyses. RESULTS Chronic exposure of HPNE and Capan1 cells to CSE caused them to increase markers of stem cells, including autofluorescence and sphere formation, compared with control cells. These cells increased expression of ABCG2, SOX9, and PAF1, via cholinergic receptor nicotinic alpha 7 subunit (CHRNA7) signaling to mitogen-activated protein kinase 1 and FOSL1. CSE-exposed pancreatic cells with knockdown of PAF1 did not show stem cell features. Exposure of cells to NNN and NNK led to increased expression of CHRNA7, FOSL1, and PAF1 along with stem cell features. Pancreata from KrasG12D; Pdx1-Cre mice exposed to cigarette smoke had increased levels of PAF1 mRNA and protein, compared with control mice, as well as increased expression of SOX9. Levels of PAF1 and FOSL1 were increased in PDAC tissues, especially those from smokers, compared with nontumor pancreatic tissue. CSE exposure increased expression of PHD-finger protein 5A, a pluripotent transcription factor and its interaction with PAF1. CONCLUSIONS Exposure to cigarette smoke activates stem cell features of pancreatic cells, via CHRNA7 signaling and FOSL1 activation of PAF1 expression. Levels of PAF1 are increased in pancreatic tumors of humans and mice with chronic cigarette smoke exposure.
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Affiliation(s)
- Rama Krishna Nimmakayala
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Parthasarathy Seshacharyulu
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Imayavaramban Lakshmanan
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Satyanarayana Rachagani
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Seema Chugh
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Saswati Karmakar
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Sanchita Rauth
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Raghupathy Vengoji
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Pranita Atri
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Geoffrey A. Talmon
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, NE
| | - Subodh M. Lele
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, NE
| | - Lynette M. Smith
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE
| | - Ishwor Thapa
- School of Interdisciplinary Informatics, University of Nebraska at Omaha, NE
| | - Dhundy Bastola
- School of Interdisciplinary Informatics, University of Nebraska at Omaha, NE
| | - Michel M. Ouellette
- Department of Internal Medicine, College of Medicine, University of Nebraska medical Center, Omaha, NE
| | - Surinder K. Batra
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA,Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE,Correspondence: Moorthy P. Ponnusamy and Surinder K. Batra, Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5870, U.S.A., Phone: 402-559-1170, Fax: 402-559-6650, (M.P.P) and (S.K.B)
| | - Moorthy P. Ponnusamy
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA,Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE,Correspondence: Moorthy P. Ponnusamy and Surinder K. Batra, Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5870, U.S.A., Phone: 402-559-1170, Fax: 402-559-6650, (M.P.P) and (S.K.B)
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19
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Old Sonic Hedgehog, new tricks: a new paradigm in thoracic malignancies. Oncotarget 2018; 9:14680-14691. [PMID: 29581874 PMCID: PMC5865700 DOI: 10.18632/oncotarget.24411] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 01/25/2018] [Indexed: 01/06/2023] Open
Abstract
The Sonic Hedgehog (Shh) pathway is physiologically involved during embryogenesis, but is also activated in several diseases, including solid cancers. Previous studies have demonstrated that the Shh pathway is involved in oncogenesis, tumor progression and chemoresistance in lung cancer and mesothelioma. The Shh pathway is also closely associated with epithelial-mesenchymal transition and cancer stem cells. Recent findings have revealed that a small proportion of lung cancer cells expressed an abnormal full-length Shh protein, associated with cancer stem cell features. In this paper, we review the role of the Shh pathway in thoracic cancers (small cell lung cancer, non-small cell lung cancer, and mesothelioma) and discuss the new perspectives of cancer research highlighted by the recent data of the literature.
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20
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Karmakar S, Dey P, Vaz AP, Bhaumik SR, Ponnusamy MP, Batra SK. PD2/PAF1 at the Crossroads of the Cancer Network. Cancer Res 2018; 78:313-319. [PMID: 29311159 DOI: 10.1158/0008-5472.can-17-2175] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/29/2017] [Accepted: 11/06/2017] [Indexed: 12/31/2022]
Abstract
Pancreatic differentiation 2 (PD2)/RNA polymerase II-associated factor 1 (PAF1) is the core subunit of the human PAF1 complex (PAF1C) that regulates the promoter-proximal pausing of RNA polymerase II as well as transcription elongation and mRNA processing and coordinates events in mRNA stability and quality control. As an integral part of its transcription-regulatory function, PD2/PAF1 plays a role in posttranslational histone covalent modifications as well as regulates expression of critical genes of the cell-cycle machinery. PD2/PAF1 alone, and as a part of PAF1C, provides distinct roles in the maintenance of self-renewal of embryonic stem cells and cancer stem cells, and in lineage differentiation. Thus, PD2/PAF1 malfunction or its altered abundance is likely to affect normal cellular functions, leading to disease states. Indeed, PD2/PAF1 is found to be upregulated in poorly differentiated pancreatic cancer cells and has the capacity for neoplastic transformation when ectopically expressed in mouse fibroblast cells. Likewise, PD2/PAF1 is upregulated in pancreatic and ovarian cancer stem cells. Here, we concisely describe multifaceted roles of PD2/PAF1 associated with oncogenic transformation and implicate PD2/PAF1 as an attractive target for therapeutic development to combat malignancy. Cancer Res; 78(2); 313-9. ©2018 AACR.
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Affiliation(s)
- Saswati Karmakar
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Parama Dey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Arokia P Vaz
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Sukesh R Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois
| | - Moorthy P Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska.,Eppley Institute for Research in Cancer and Allied Diseases and Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska. .,Eppley Institute for Research in Cancer and Allied Diseases and Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska
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21
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Ferdoush J, Karmakar S, Barman P, Kaja A, Uprety B, Batra SK, Bhaumik SR. Ubiquitin–Proteasome System Regulation of an Evolutionarily Conserved RNA Polymerase II-Associated Factor 1 Involved in Pancreatic Oncogenesis. Biochemistry 2017; 56:6083-6086. [PMID: 29023102 DOI: 10.1021/acs.biochem.7b00865] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The evolutionarily conserved RNA polymerase II-associated factor 1 (Paf1) from yeast to humans regulates transcription and associated processes, and thus, malfunctions and/or misregulations of Paf1 are associated with cellular pathologies. Indeed, Paf1 (also known as PD2 or pancreatic differentiation 2) is found to be upregulated in poorly differentiated cancer cells, and such upregulation is involved in cellular transformation or oncogenesis. However, the basis for Paf1 upregulation in these cells remains largely unknown. In light of this, we have tested here the idea that the ubiquitin-proteasome system (UPS) regulates the cellular abundance of Paf1. In this direction, we analyzed the role of UPS in regulation of Paf1's abundance in yeast. We find that Paf1 undergoes ubiquitylation and is degraded by the 26S proteasome in yeast, thus deciphering UPS regulation of an evolutionarily conserved factor, Paf1, involved in various cellular processes at the crossroads of the cancer networks. Likewise, Paf1 undergoes proteasomal degradation in well-differentiated, but not poorly differentiated, pancreatic cancer cells, hence pointing to the UPS in upregulation of Paf1 in poorly differentiated cancers. Collectively, our results reveal UPS regulation of Paf1 and suggest downregulation of UPS in elevating Paf1's abundance in poorly differentiated cancers.
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Affiliation(s)
- Jannatul Ferdoush
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Saswati Karmakar
- Department
of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Priyanka Barman
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Amala Kaja
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Bhawana Uprety
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
| | - Surinder K. Batra
- Department
of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Sukesh R. Bhaumik
- Department
of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, United States
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22
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PAF1 complex component Leo1 helps recruit Drosophila Myc to promoters. Proc Natl Acad Sci U S A 2017; 114:E9224-E9232. [PMID: 29078288 DOI: 10.1073/pnas.1705816114] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Myc oncogene is a transcription factor with a powerful grip on cellular growth and proliferation. The physical interaction of Myc with the E-box DNA motif has been extensively characterized, but it is less clear whether this sequence-specific interaction is sufficient for Myc's binding to its transcriptional targets. Here we identify the PAF1 complex, and specifically its component Leo1, as a factor that helps recruit Myc to target genes. Since the PAF1 complex is typically associated with active genes, this interaction with Leo1 contributes to Myc targeting to open promoters.
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23
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Karmakar S, Seshacharyulu P, Lakshmanan I, Vaz AP, Chugh S, Sheinin YM, Mahapatra S, Batra SK, Ponnusamy MP. hPaf1/PD2 interacts with OCT3/4 to promote self-renewal of ovarian cancer stem cells. Oncotarget 2017; 8:14806-14820. [PMID: 28122356 PMCID: PMC5362445 DOI: 10.18632/oncotarget.14775] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/11/2017] [Indexed: 01/06/2023] Open
Abstract
Cancer stem cells (CSCs), which mediate drug resistance and disease recurrence in several cancers, are therapeutically relevant to ovarian cancer (OC), wherein approximately 80% of patients manifest with tumor recurrence. While there are several markers for ovarian CSCs (OCSCs), the mechanism for their self-renewal maintenance by unique driver/markers is poorly understood. Here, we evaluated the role of hPaf1/PD2, a core component of RNA Polymerase II-Associated Factor (PAF) complex, in self-renewal of OCSCs through marker and functional analyses, including CRISPR/Cas9-silencing of hPaf1/PD2 in OCSCs and provided a possible mechanism for maintenance of OCSCs. Expression of hPaf1/PD2 showed moderate to intense staining in 32.4% of human OC tissues, whereas 67.6% demonstrated basal expression by immunohistochemistry analysis, implying that the minor proportion of cells overexpressing hPaf1/PD2 could be putative OCSCs. Isolated OCSCs showed higher expression of hPaf1/PD2 along with established CSC and self-renewal markers. Knockdown of hPaf1/PD2 in OCSCs resulted in a significant downregulation of CSC and self-renewal markers, and impairment of in vitro tumor sphere (P < 0.05) and colony formation (P = 0.013). Co-immunoprecipitation revealed that OCT3/4 specifically interacts with hPaf1/PD2, and not with other PAF components (Ctr9, Leo1, Parafibromin) in OCSCs, suggesting a complex-independent role for hPaf1/PD2 in OCSC maintenance. Moreover, there was a significant overexpression and co-localization of hPaf1/PD2 with OCT3/4 in OC tissues compared to normal ovary tissues. Our results indicate that hPaf1/PD2 is overexpressed in OCSCs and maintains the self-renewal of OCSCs through its interaction with OCT3/4; thus, hPaf1/PD2 may be a potential therapeutic target to overcome tumor relapse in OC.
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Affiliation(s)
- Saswati Karmakar
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | | | - Imayavaramban Lakshmanan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Arokia P Vaz
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Seema Chugh
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Yuri M Sheinin
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sidharth Mahapatra
- Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE, USA
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.,Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Disease, University of Nebraska Medical Center, Omaha, NE, USA
| | - Moorthy P Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.,Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Disease, University of Nebraska Medical Center, Omaha, NE, USA
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24
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Van Oss SB, Cucinotta CE, Arndt KM. Emerging Insights into the Roles of the Paf1 Complex in Gene Regulation. Trends Biochem Sci 2017; 42:788-798. [PMID: 28870425 PMCID: PMC5658044 DOI: 10.1016/j.tibs.2017.08.003] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 12/21/2022]
Abstract
The conserved, multifunctional Polymerase-Associated Factor 1 complex (Paf1C) regulates all stages of the RNA polymerase (Pol) II transcription cycle. In this review, we examine a diverse set of recent studies from various organisms that build on foundational studies in budding yeast. These studies identify new roles for Paf1C in the control of gene expression and the regulation of chromatin structure. In exploring these advances, we find that various functions of Paf1C, such as the regulation of promoter-proximal pausing and development in higher eukaryotes, are complex and context dependent. As more becomes known about the role of Paf1C in human disease, interest in the molecular mechanisms underpinning Paf1C function will continue to increase.
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Affiliation(s)
- S Branden Van Oss
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Christine E Cucinotta
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Karen M Arndt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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25
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The PAF complex regulation of Prmt5 facilitates the progression and maintenance of MLL fusion leukemia. Oncogene 2017; 37:450-460. [PMID: 28945229 PMCID: PMC5785415 DOI: 10.1038/onc.2017.337] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 07/20/2017] [Accepted: 07/31/2017] [Indexed: 02/06/2023]
Abstract
Acute myeloid leukemia (AML) is a disease associated with epigenetic dysregulation. 11q23 translocations involving the H3K4 methyltransferase MLL1 (KMT2A) generate oncogenic fusion proteins with deregulated transcriptional potential. The Polymerase Associated Factor complex (PAFc) is an epigenetic co-activator complex that makes direct contact with MLL fusion proteins and is involved in AML, however its functions are not well understood. Here, we explored the transcriptional targets regulated by the PAFc that facilitate leukemia by performing RNA-sequencing after conditional loss of the PAFc subunit Cdc73. We found Cdc73 promotes expression of an early hematopoietic progenitor gene program that prevents differentiation. Among the target genes, we confirmed the protein arginine methyltransferase Prmt5 is a direct target that is positively regulated by a transcriptional unit that includes the PAFc, MLL1, HOXA9 and STAT5 in leukemic cells. We observed reduced PRMT5-mediated H4R3me2s following excision of Cdc73 placing this histone modification downstream of the PAFc and revealing a novel mechanism between the PAFc and Prmt5. Knock down or pharmacologic inhibition of Prmt5 causes a G1 arrest and reduced proliferation resulting in extended leukemic disease latency in vivo. Overall, we demonstrate the PAFc regulates Prmt5 to facilitate leukemic progression and is a potential therapeutic target for AMLs.
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Zeng H, Xu W. Ctr9, a key subunit of PAFc, affects global estrogen signaling and drives ERα-positive breast tumorigenesis. Genes Dev 2016; 29:2153-67. [PMID: 26494790 PMCID: PMC4617979 DOI: 10.1101/gad.268722.115] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Zeng and Xu discovered that Ctr9, a key subunit of hPAFc, is a central regulator of estrogen signaling that drives ERα+ breast tumorigenesis, rendering it a potential target for the treatment of ERα+ breast cancer. The human RNA polymerase II (RNAPII)-associated factor complex (hPAFc) and its individual subunits have been implicated in human diseases, including cancer. However, its involvement in breast cancer awaits investigation. Using data mining and human breast cancer tissue microarrays, we found that Ctr9, the key scaffold subunit in hPAFc, is highly expressed in estrogen receptor α-positive (ERα+) luminal breast cancer, and the high expression of Ctr9 correlates with poor prognosis. Knockdown of Ctr9 in ERα+ breast cancer cells almost completely erased estrogen-regulated transcriptional response. At the molecular level, Ctr9 enhances ERα protein stability, promotes recruitment of ERα and RNAPII, and stimulates transcription elongation and transcription-coupled histone modifications. Knockdown of Ctr9, but not other hPAFc subunits, alters the morphology, proliferative capacity, and tamoxifen sensitivity of ERα+ breast cancer cells. Together, our study reveals that Ctr9, a key subunit of hPAFc, is a central regulator of estrogen signaling that drives ERα+ breast tumorigenesis, rendering it a potential target for the treatment of ERα+ breast cancer.
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Affiliation(s)
- Hao Zeng
- McArdle Laboratory for Cancer Research, Graduate Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Wei Xu
- McArdle Laboratory for Cancer Research, Graduate Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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27
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Vaz AP, Deb S, Rachagani S, Dey P, Muniyan S, Lakshmanan I, Karmakar S, Smith L, Johansson S, Lele S, Ouellette M, Ponnusamy MP, Batra SK. Overexpression of PD2 leads to increased tumorigenicity and metastasis in pancreatic ductal adenocarcinoma. Oncotarget 2016; 7:3317-31. [PMID: 26689992 PMCID: PMC4823108 DOI: 10.18632/oncotarget.6580] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/16/2015] [Indexed: 12/14/2022] Open
Abstract
Pancreatic differentiation 2 (PD2), an important subunit of the human PAF complex, was identified after differential screening analysis of 19q13 amplicon, and its overexpression induces oncogenic transformation of NIH3T3 cells, hence raising the possibility of a role for PD2 in tumorigenesis and metastasis. To test this hypothesis, we analyzed here the functional role and clinical significance of PD2 in pancreatic ductal adenocarcinoma (PDAC) and its pathogenesis. Using immunohistochemical analysis, we found that PD2 is detected in the acini but not in the ducts in the normal pancreas. In human PDAC specimens, PD2 was instead primarily detected in the ducts (12/48 patients 25%; p-value < 0.0001), thereby showing that PDAC correlates with increased ductal expression of PD2. Consistently, PD2 expression was increased in telomerase-immortalized human pancreatic ductal cells (HPNE cells) modified to express the HPV16 E6 and E7 proteins, whose respective functions are to block p53 and RB. In addition, ectopic expression of PD2 in PDAC cells (Capan-1 and SW1990) led to increased clonogenicity and migration in vitro, and tumor growth and metastasis in vivo. Interestingly, PD2 overexpression also resulted in enrichment of cancer stem cells (CSCs) and upregulation of oncogenes such as c-Myc and cell cycle progression marker, cyclin D1. Taken together, our results support that PD2 is overexpressed in the ducts of PDAC tissues, and results in tumorigenesis and metastasis via upregulation of oncogenes such as c-Myc and cyclin hence D1 implicating PD2 upregulation in pancreatic oncogenesis with targeted therapeutic potential.
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MESH Headings
- Adenocarcinoma/genetics
- Adenocarcinoma/metabolism
- Adenocarcinoma/secondary
- Animals
- Apoptosis
- Blotting, Western
- Carcinoma, Pancreatic Ductal/genetics
- Carcinoma, Pancreatic Ductal/metabolism
- Carcinoma, Pancreatic Ductal/secondary
- Cell Cycle
- Cell Differentiation
- Cell Movement
- Cell Proliferation
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Cells, Cultured
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- Immunoenzyme Techniques
- Mice
- Mice, Nude
- NIH 3T3 Cells
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/metabolism
- Pancreatic Neoplasms/pathology
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription Factors
- Xenograft Model Antitumor Assays
- Pancreatic Neoplasms
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Affiliation(s)
- Arokia Priyanka Vaz
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Shonali Deb
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Satyanarayana Rachagani
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Parama Dey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sakthivel Muniyan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Imayavaramban Lakshmanan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Saswati Karmakar
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Lynette Smith
- Department of Biostatistics, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sonny Johansson
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Subodh Lele
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Michel Ouellette
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Moorthy P. Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- Eppley Institute for Research in Cancer and Allied Disease, University of Nebraska Medical Center, Omaha, NE, USA
| | - Surinder K. Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
- Eppley Institute for Research in Cancer and Allied Disease, University of Nebraska Medical Center, Omaha, NE, USA
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Zhi X, Giroux-Leprieur E, Wislez M, Hu M, Zhang Y, Shi H, Du K, Wang L. Human RNA polymerase II associated factor 1 complex promotes tumorigenesis by activating c-MYC transcription in non-small cell lung cancer. Biochem Biophys Res Commun 2015; 465:685-90. [PMID: 26282204 DOI: 10.1016/j.bbrc.2015.08.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 08/04/2015] [Indexed: 10/23/2022]
Abstract
Human RNA polymerase II (RNAPII)-associated factor 1 complex (hPAF1C) plays a crucial role in protein-coding gene transcription. Overexpression of hPAF1C has been implicated in the initiation and progression of various human cancers. However, the molecular pathways involved in tumorigenesis through hPAF1C remain to be elucidated. The current study suggested hPAF1C expression as a prognostic biomarker for early stage non-small cell lung cancer (NSCLC) and patients with low hPAF1C expression levels had significantly better overall survival. Furthermore, the expression of hPAF1C was found to be positively correlated with c-MYC expression in patient tumor samples and in cancer cell lines. Mechanistic studies indicated that hPAF1C could promote lung cancer cell proliferation through regulating c-MYC transcription. These results demonstrated the prognostic value of hPAF1C in early-stage NSCLC and the role of hPAF1C in the transcriptional regulation of c-MYC oncogene during NSCLC tumorigenesis.
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Affiliation(s)
- Xiuyi Zhi
- Department of Thoracic Surgery, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China
| | - Etienne Giroux-Leprieur
- ER2 GRC UPMC04 Theranoscan, Pierre et Marie Curie University, Tenon Hospital, 4 Rue de La Chine, 75020, Paris, France; Respiratory Diseases and Thoracic Oncology Department, Ambroise Pare Hospital - APHP, Versailles Saint Quentin en Yvelines University, 9 Avenue Charles de Gaulle, 92100, Boulogne-Billancourt, France
| | - Marie Wislez
- ER2 GRC UPMC04 Theranoscan, Pierre et Marie Curie University, Tenon Hospital, 4 Rue de La Chine, 75020, Paris, France
| | - Mu Hu
- Department of Thoracic Surgery, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China
| | - Yi Zhang
- Department of Thoracic Surgery, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China
| | - Huaiyin Shi
- Department of Pathology, Chinese PLA General Hospital, Fu-xing Road #28, Beijing, 100853, China
| | - Kaiqi Du
- Department of Cardiothoracic Surgery, Chinese People's Armed Police Force, Zhejiang Corps Hospital, Jiaxing, Zhejiang Province, China.
| | - Lei Wang
- Department of Human Anatomy, Hebei Medical University, Hebei Province, China.
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Protein Degradation of RNA Polymerase II-Association Factor 1(PAF1) Is Controlled by CNOT4 and 26S Proteasome. PLoS One 2015; 10:e0125599. [PMID: 25933433 PMCID: PMC4416890 DOI: 10.1371/journal.pone.0125599] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/24/2015] [Indexed: 12/21/2022] Open
Abstract
The PAF complex (PAFc) participates in various steps of the transcriptional process, from initiation to termination, by interacting with and recruiting various proteins to the proper locus for each step. PAFc is an evolutionarily conserved, multi-protein complex comprising PAF1, CDC73, CTR9, LEO1, yRTF1 and, in humans, hSKI8. These components of PAFc work together, and their protein levels are closely interrelated. In the present study, we investigated the mechanism of PAF1 protein degradation. We found that PAF1 protein levels are negatively regulated by the expression of CNOT4, an ortholog of yNOT4 and a member of the CCR4-NOT complex. CNOT4 specifically controls PAF1 but not other components of PAFc at the protein level by regulating the polyubiquitination of PAF1 and its subsequent degradation by the 26S proteasome. The degradation of PAF1 was found to require nuclear localization, as no PAF1 degradation by CNOT4 and the 26S proteasome was observed with NLS (nucleus localization signal)-deficient PAF1 mutants. However, chromatin binding by PAF1 was not necessary for 26S proteasome- or CNOT4-mediated degradation. Our results suggest that CNOT4 controls the degradation of chromatin-unbound PAF1 via the 26S proteasome.
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30
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Vaz AP, Ponnusamy MP, Rachagani S, Dey P, Ganti AK, Batra SK. Novel role of pancreatic differentiation 2 in facilitating self-renewal and drug resistance of pancreatic cancer stem cells. Br J Cancer 2014; 111:486-96. [PMID: 25003666 PMCID: PMC4119968 DOI: 10.1038/bjc.2014.152] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 02/27/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Cancer stem cells (CSCs) contribute towards disease aggressiveness and drug resistance. Specific identification of CSC maintenance genes and targeting can improve the efficiency of currently available treatment modalities. Pancreatic differentiation 2 (PD2) has a major role in the self-renewal of mouse embryonic stem cells. In the present study, we investigated the role of PD2 in pancreatic CSCs. METHODS Characterisation of CSCs and non-CSCs from mouse models, pancreatic cancer cells and human tissues by CSC and self-renewal marker analysis using confocal assay. Effect of PD2 knockdown in CSCs (after gemcitabine treatment) was studied by immunoblot and apoptosis assays. RESULTS A subpopulation of cells displayed PD2 overexpression in mouse (Kras(G12D); Pdx1-Cre and Kras(G12D); Trp53(R172H/+); Pdx1-Cre) and human pancreatic tumours, which co-express CSC markers. Cancer stem cells exhibited elevated expression of PD2 and self-renewal markers, such as Oct3/4, Shh and β-catenin. Gemcitabine treatment maintained the CSC population with simultaneous maintenance of PD2 and CSC marker expression. Knockdown of PD2 in CSCs resulted in reduced viability of cells and enhanced apoptosis along with abrogated expression of CD133 and MDR2. CONCLUSIONS Our results suggest that PD2 is a novel CSC maintenance protein, loss of which renders the CSCs more susceptible to drug-induced cell death.
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Affiliation(s)
- A P Vaz
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - M P Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - S Rachagani
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - P Dey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - A K Ganti
- 1] Department of Internal Medicine, VA Nebraska Western Iowa Health Care System, University of Nebraska Medical Center, Omaha, NE, USA [2] Division of Oncology-Hematology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - S K Batra
- 1] Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA [2] Buffet Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
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31
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Dey P, Rachagani S, Vaz AP, Ponnusamy MP, Batra SK. PD2/Paf1 depletion in pancreatic acinar cells promotes acinar-to-ductal metaplasia. Oncotarget 2014; 5:4480-91. [PMID: 24947474 PMCID: PMC4147339 DOI: 10.18632/oncotarget.2041] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 05/28/2014] [Indexed: 01/29/2023] Open
Abstract
Pancreatic differentiation 2 (PD2), a PAF (RNA Polymerase II Associated Factor) complex subunit, is overexpressed in pancreatic cancer cells and has demonstrated potential oncogenic property. Here, we report that PD2/Paf1 expression was restricted to acinar cells in the normal murine pancreas, but its expression increased in the ductal cells of KrasG12D/Pdx1Cre (KC) mouse model of pancreatic cancer with increasing age, showing highest expression in neoplastic ductal cells of 50 weeks old mice. PD2/Paf1 was specifically expressed in amylase and CK19 double positive metaplastic ducts, representing intermediate structures during pancreatic acinar-to-ductal metaplasia (ADM). Similar PD2/Paf1 expression was observed in murine pancreas that exhibited ADM-like histology upon cerulein challenge. In normal mice, cerulein-mediated inflammation induced a decrease in PD2/Paf1 expression, which was later restored upon recovery of the pancreatic parenchyma. In KC mice, however, PD2/Paf1 mRNA level continued to decrease with progressive dysplasia and subsequent neoplastic transformation. Additionally, knockdown of PD2/Paf1 in pancreatic acinar cells resulted in the abrogation of Amylase, Elastase and Lipase (acinar marker) mRNA levels with simultaneous increase in CK19 and CAII (ductal marker) transcripts. In conclusion, our studies indicate loss of PD2/Paf1 expression during acinar transdifferentiation in pancreatic cancer initiation and PD2/Paf1 mediated regulation of lineage specific markers.
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Affiliation(s)
- Parama Dey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Satyanarayana Rachagani
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Arokia P. Vaz
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Moorthy P. Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
| | - Surinder K. Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, U.S.A
- Fred & Pamela Buffet Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, U.S.A
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, U.S.A
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32
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The PAF1 complex is involved in embryonic epidermal morphogenesis in Caenorhabditis elegans. Dev Biol 2014; 391:43-53. [PMID: 24721716 DOI: 10.1016/j.ydbio.2014.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 03/29/2014] [Accepted: 04/02/2014] [Indexed: 11/21/2022]
Abstract
The PAF1 complex (PAF1C) is an evolutionarily conserved protein complex involved in transcriptional regulation and chromatin remodeling. How the PAF1C is involved in animal development is still not well understood. Here, we report that, in the nematode Caenorhabditis elegans, the PAF1C is involved in epidermal morphogenesis in late embryogenesis. From an RNAi screen we identified the C. elegans ortholog of a component of the PAF1C, CTR-9, as a gene whose depletion caused various defects during embryonic epidermal morphogenesis, including epidermal cell positioning, ventral enclosure and epidermal elongation. RNAi of orthologs of other four components of the PAF1C (PAFO-1, LEO-1, CDC-73 and RTFO-1) caused similar epidermal defects. In these embryos, whereas the number and cell fate determination of epidermal cells were apparently unaffected, their position and shape were severely disorganized. PAFO-1::mCherry, mCherry::LEO-1 and GFP::RTFO-1 driven by the authentic promoters were detected in the nuclei of a wide range of cells. Nuclear localization of GFP::RTFO-1 was independent of other PAF1C components, while PAFO-1::mCherry and mCherry::LEO-1 dependent on other components except RTFO-1. Epidermis-specific expression of mCherry::LEO-1 rescued embryonic lethality of the leo-1 deletion mutant. Thus, although the PAF1C is universally expressed in C. elegans embryos, its epidermal function is crucial for the viability of this animal.
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Wang YW, Li WM, Wu WJ, Chai CY, Liu HS, Lai MD, Chow NH. Potential significance of EMP3 in patients with upper urinary tract urothelial carcinoma: crosstalk with ErbB2-PI3K-Akt pathway. J Urol 2013; 192:242-51. [PMID: 24333112 DOI: 10.1016/j.juro.2013.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2013] [Indexed: 02/06/2023]
Abstract
PURPOSE Upper urinary tract (pyelocalyceal cavities and ureter) urothelial carcinoma is a relatively rare neoplastic disease. Although diagnosis and treatment of this tumor variant have improved significantly, accurate risk stratification remains a challenge. To identify the putative oncogene involved in urothelial carcinoma progression we performed bioinformatics guided experimental investigation targeting chromosome 19q13. MATERIALS AND METHODS We investigated the effects of EMP3 on cancer cell growth, migration and adhesion in transfection and siRNA experiments in vitro. Crosstalk of integrins or ErbB2 with EMP3 was examined by reverse transcriptase-polymerase chain reaction and immunoblot. The potential involvement of epigenetic alterations of EMP3 in vitro and in vivo was analyzed by methylation specific polymerase chain reaction. To validate clinical relevance we measured EMP3 expression at the mRNA and protein levels in a cohort of 77 patients with upper urinary tract urothelial carcinoma and compared prognostic significance in relation to that of ErbB2 expression. RESULTS We noted functional crosstalk between ErbB2 and EMP3 in vitro. EMP3 over expression promoted cancer cell proliferation and migration but suppressed cell adhesion in vitro. EMP3 activated the ErbB2-PI3K-AKT pathway to increase cell growth in vitro. In the clinical cohort Kaplan-Meier survival estimates showed that ErbB2 and EMP3 co-expression was the most important indicator of progression-free and metastasis-free survival in patients with upper urinary tract urothelial carcinoma (log rank test p = 0.018 and 0.04, respectively). CONCLUSIONS EMP3 is an important prognostic indicator for selecting patients with upper urinary tract urothelial carcinoma for more intensive therapy. EMP3 is an innovative co-targeting candidate for designing ErbB2 based cancer therapy.
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Affiliation(s)
- Yi-Wen Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Wei-Ming Li
- Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, Republic of China
| | - Wen-Jeng Wu
- Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, Republic of China; Department of Urology, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan, Republic of China; Department of Urology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Republic of China
| | - Chee-Yin Chai
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, Republic of China
| | - Hsiao-Sheng Liu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China; Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Ming-Derg Lai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China; Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Nan-Haw Chow
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China; Department of Pathology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China.
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Huang Q, Zhang J, Peng S, Du M, Ow S, Pu H, Pan C, Shen H. Proteomic analysis of perfluorooctane sulfonate-induced apoptosis in human hepatic cells using the iTRAQ technique. J Appl Toxicol 2013; 34:1342-51. [PMID: 24301089 DOI: 10.1002/jat.2963] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 10/10/2013] [Accepted: 10/14/2013] [Indexed: 01/09/2023]
Abstract
Perfluorooctane sulfonate (PFOS) is one of the most commonly used perfluorinated compounds, whose environmental exposure has been associated with a number of adverse health outcomes. However, the molecular mechanisms involved in PFOS toxicity are still not well elucidated. In the present study, we applied iTRAQ labeling quantitative proteomic technology to investigate the differential protein expression profiles of non-tumor human hepatic cells (L-02) exposed to PFOS. A total of 18 proteins were differentially expressed in a dose-dependent manner in PFOS-treated cells versus the control. Among these, 11 proteins were up-regulated and 7 were down-regulated. Gene ontology analysis indicated that PFOS would exert toxic effects on L-02 cells by affecting multiple biological processes, including protein biosynthesis and degradation, mRNA processing and splicing, transcription, signal transduction and transport. Furthermore, the proteomic results especially proposed that the inhibition of HNRNPC, HUWE1 and UBQLN1, as well as the induction of PAF1 is involved in the activation of the p53 and c-myc signaling pathways, which then trigger the apoptotic process in L-02 cells exposed to PFOS. Overall, these data will aid our understanding of the mechanisms responsible for PFOS-mediated hepatotoxicity, and develop useful biomarkers for monitoring and evaluating PFOS contamination in the environment.
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Affiliation(s)
- Qingyu Huang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
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Abstract
Solitary fibrous tumors (SFTs) are unusual spindle cell neoplasms initially described in the pleura but have since been discovered in many extrapleural locations. SFT of the kidney is extremely rare, the majority occurring in middle-aged adults. To date, only two pediatric cases of renal SFT have been reported. We report a case of large SFT in the kidney of a 3-year-old boy that was clinically and radiologically thought to be a nephroblastoma. This case is the first pediatric renal SFT to be reported with detailed histopathologic and cytogenetic analyses. SFT should be included in the differential diagnosis of pediatric renal tumors.
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Affiliation(s)
- William W. Wu
- University of California Irvine Medical Center, Orange, CA, USA
| | - Julia T. Chu
- University of California Irvine Medical Center, Orange, CA, USA
| | | | - Lisa Shane
- Long Beach Memorial Medical Center, Long Beach, CA, USA
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36
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Kim N, Sun HY, Youn MY, Yoo JY. IL-1β-specific recruitment of GCN5 histone acetyltransferase induces the release of PAF1 from chromatin for the de-repression of inflammatory response genes. Nucleic Acids Res 2013; 41:4495-506. [PMID: 23502002 PMCID: PMC3632138 DOI: 10.1093/nar/gkt156] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
To determine the functional specificity of inflammation, it is critical to orchestrate the timely activation and repression of inflammatory responses. Here, we explored the PAF1 (RNA polymerase II associated factor)-mediated signal- and locus-specific repression of genes induced through the pro-inflammatory cytokine interleukin (IL)-1β. Using microarray analysis, we identified the PAF1 target genes whose expression was further enhanced by PAF1 knockdown in IL-1β–stimulated HepG2 hepatocarcinomas. PAF1 bound near the transcription start sites of target genes and dissociated on stimulation. In PAF1-deficient cells, more elongating RNA polymerase II and acetylated histones were observed, although IL-1β–mediated activation and recruitment of nuclear factor κB (NF-κB) were not altered. Under basal conditions, PAF1 blocked histone acetyltransferase general control non-depressible 5 (GCN5)-mediated acetylation on H3K9 and H4K5 residues. On IL-1β stimulation, activated GCN5 discharged PAF1 from chromatin, allowing productive transcription to occur. PAF1 bound to histones but not to acetylated histones, and the chromatin-binding domain of PAF1 was essential for target gene repression. Moreover, IL-1β–induced cell migration was similarly controlled through counteraction between PAF1 and GCN5. These results suggest that the IL-1β signal-specific exchange of PAF1 and GCN5 on the target locus limits inappropriate gene induction and facilitates the timely activation of inflammatory responses.
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Affiliation(s)
- Nari Kim
- Division of Molecular and Life Sciences, Department of Life Sciences, Pohang University of Science and Technology POSTECH, Pohang 790-784, Republic of Korea
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Effects of the Paf1 complex and histone modifications on snoRNA 3'-end formation reveal broad and locus-specific regulation. Mol Cell Biol 2012; 33:170-82. [PMID: 23109428 DOI: 10.1128/mcb.01233-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Across diverse eukaryotes, the Paf1 complex (Paf1C) plays critical roles in RNA polymerase II transcription elongation and regulation of histone modifications. Beyond these roles, the human and Saccharomyces cerevisiae Paf1 complexes also interact with RNA 3'-end processing components to affect transcript 3'-end formation. Specifically, the Saccharomyces cerevisiae Paf1C functions with the RNA binding proteins Nrd1 and Nab3 to regulate the termination of at least two small nucleolar RNAs (snoRNAs). To determine how Paf1C-dependent functions regulate snoRNA formation, we used high-density tiling arrays to analyze transcripts in paf1Δ cells and uncover new snoRNA targets of Paf1. Detailed examination of Paf1-regulated snoRNA genes revealed locus-specific requirements for Paf1-dependent posttranslational histone modifications. We also discovered roles for the transcriptional regulators Bur1-Bur2, Rad6, and Set2 in snoRNA 3'-end formation. Surprisingly, at some snoRNAs, this function of Rad6 appears to be primarily independent of its role in histone H2B monoubiquitylation. Cumulatively, our work reveals a broad requirement for the Paf1C in snoRNA 3'-end formation in S. cerevisiae, implicates the participation of transcriptional proteins and histone modifications in this process, and suggests that the Paf1C contributes to the fine tuning of nuanced levels of regulation that exist at individual loci.
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The many roles of the conserved eukaryotic Paf1 complex in regulating transcription, histone modifications, and disease states. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:116-26. [PMID: 22982193 DOI: 10.1016/j.bbagrm.2012.08.011] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/18/2012] [Accepted: 08/29/2012] [Indexed: 12/20/2022]
Abstract
The Paf1 complex was originally identified over fifteen years ago in budding yeast through its physical association with RNA polymerase II. The Paf1 complex is now known to be conserved throughout eukaryotes and is well studied for promoting RNA polymerase II transcription elongation and transcription-coupled histone modifications. Through these critical regulatory functions, the Paf1 complex participates in numerous cellular processes such as gene expression and silencing, RNA maturation, DNA repair, cell cycle progression and prevention of disease states in higher eukaryotes. In this review, we describe the historic and current research involving the eukaryotic Paf1 complex to explain the cellular roles that underlie its conservation and functional importance. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation.
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Paf1 restricts Gcn4 occupancy and antisense transcription at the ARG1 promoter. Mol Cell Biol 2012; 32:1150-63. [PMID: 22252319 DOI: 10.1128/mcb.06262-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The conserved Paf1 complex negatively regulates the expression of numerous genes, yet the mechanisms by which it represses gene expression are not well understood. In this study, we use the ARG1 gene as a model to investigate the repressive functions of the Paf1 complex in Saccharomyces cerevisiae. Our results indicate that Paf1 mediates repression of the ARG1 gene independently of the gene-specific repressor, ArgR/Mcm1. Rather, by promoting histone H2B lysine 123 ubiquitylation, Paf1 represses the ARG1 gene by negatively affecting Gcn4 occupancy at the promoter. Consistent with this observation, Gcn5 and its acetylation sites on histone H3 are required for full ARG1 derepression in paf1Δ cells, and the repressive effect of Paf1 is largely maintained when the ARG1 promoter directs transcription of a heterologous coding region. Derepression of the ARG1 gene in paf1Δ cells is accompanied by small changes in nucleosome occupancy, although these changes are subtle in comparison to those that accompany gene activation through amino acid starvation. Additionally, conditions that stimulate ARG1 transcription, including PAF1 deletion, lead to increased antisense transcription across the ARG1 promoter. This promoter-associated antisense transcription positively correlates with ARG1 sense transcription. Finally, our results indicate that Paf1 represses other genes through mechanisms similar to those used at the ARG1 gene.
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Crisucci EM, Arndt KM. The Roles of the Paf1 Complex and Associated Histone Modifications in Regulating Gene Expression. GENETICS RESEARCH INTERNATIONAL 2011; 2011. [PMID: 22408743 PMCID: PMC3296560 DOI: 10.4061/2011/707641] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The conserved Paf1 complex (Paf1C) carries out multiple functions during transcription by RNA polymerase (pol) II, and these functions are required for the proper expression of numerous genes in yeast and metazoans. In the elongation stage of the transcription cycle, the Paf1C associates with RNA pol II, interacts with other transcription elongation factors, and facilitates modifications to the chromatin template. At the end of elongation, the Paf1C plays an important role in the termination of RNA pol II transcripts and the recruitment of proteins required for proper RNA 3′ end formation. Significantly, defects in the Paf1C are associated with several human diseases. In this paper, we summarize current knowledge on the roles of the Paf1C in RNA pol II transcription.
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Affiliation(s)
- Elia M Crisucci
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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The Paf1 complex represses SER3 transcription in Saccharomyces cerevisiae by facilitating intergenic transcription-dependent nucleosome occupancy of the SER3 promoter. EUKARYOTIC CELL 2011; 10:1283-94. [PMID: 21873510 DOI: 10.1128/ec.05141-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Previous studies have shown that repression of the Saccharomyces cerevisiae SER3 gene is dependent on transcription of SRG1 from noncoding DNA initiating within the intergenic region 5' of SER3 and extending across the SER3 promoter region. By a mechanism dependent on the activities of the Swi/Snf chromatin remodeling factor, the HMG-like factor Spt2, and the Spt6 and Spt16 histone chaperones, SRG1 transcription deposits nucleosomes over the SER3 promoter to prevent transcription factors from binding and activating SER3. In this study, we uncover a role for the Paf1 transcription elongation complex in SER3 repression. We find that SER3 repression is primarily dependent on the Paf1 and Ctr9 subunits of this complex, with minor contributions by the Rtf1, Cdc73, and Leo1 subunits. We show that the Paf1 complex localizes to the SRG1 transcribed region under conditions that repress SER3, consistent with it having a direct role in mediating SRG1 transcription-dependent SER3 repression. Importantly, we show that the defect in SER3 repression in strains lacking Paf1 subunits is not a result of reduced SRG1 transcription or reduced levels of known Paf1 complex-dependent histone modifications. Rather, we find that strains lacking subunits of the Paf1 complex exhibit reduced nucleosome occupancy and reduced recruitment of Spt16 and, to a lesser extent, Spt6 at the SER3 promoter. Taken together, our results suggest that Paf1 and Ctr9 repress SER3 by maintaining SRG1 transcription-dependent nucleosome occupancy.
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Schneider DA. RNA polymerase I activity is regulated at multiple steps in the transcription cycle: recent insights into factors that influence transcription elongation. Gene 2011; 493:176-84. [PMID: 21893173 DOI: 10.1016/j.gene.2011.08.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Revised: 07/11/2011] [Accepted: 08/08/2011] [Indexed: 01/21/2023]
Abstract
Synthesis of the translation apparatus is a central activity in growing and/or proliferating cells. Because of its fundamental importance and direct connection to cell proliferation, ribosome synthesis has been a focus of ongoing research for several decades. As a consequence, much is known about the essential factors involved in this process. Many studies have shown that transcription of the ribosomal DNA by RNA polymerase I is a major target for cellular regulation of ribosome synthesis rates. The initiation of transcription by RNA polymerase I has been implicated as a regulatory target, however, recent studies suggest that the elongation step in transcription is also influenced and regulated by trans-acting factors. This review describes the factors required for rRNA synthesis and focuses on recent works that have begun to identify and characterize factors that influence transcription elongation by RNA polymerase I and its regulation.
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Affiliation(s)
- David Alan Schneider
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 720 20th Street South, Kaul Human Genetics, Room 442, Birmingham, AL 35294, USA.
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Hu J, Nakhla H, Friedman E. Transient arrest in a quiescent state allows ovarian cancer cells to survive suboptimal growth conditions and is mediated by both Mirk/dyrk1b and p130/RB2. Int J Cancer 2011; 129:307-18. [PMID: 20857490 DOI: 10.1002/ijc.25692] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 09/07/2010] [Indexed: 01/12/2023]
Abstract
Some ovarian cancer cells in vivo are in a reversible quiescent state where they can contribute to cancer spread under favorable growth conditions. The serine/threonine kinase Mirk/dyrk1B was expressed in each of seven ovarian cancer cell lines and in 21 of 28 resected human ovarian cancers, and upregulated in 60% of the cancers. Some ovarian cancer cells were found in a G0 quiescent state, with the highest fraction in a line with an amplified Mirk gene. Suboptimal culture conditions increased the G0 fraction in SKOV3 and TOV21G, but not OVCAR4 cultures. Less than half as many OVCAR4 cells survived under suboptimal culture conditions as shown by total cell numbers, dye exclusion viability studies, and assay of cleaved apoptotic marker proteins. G0 arrest in TOV21G and SKOV3 cells led to increased levels of Mirk, the CDK inhibitor p27, p130/Rb2, and p130/Rb2 complexed with E2F4. The G0 arrest was transient, and cells exited G0 when fresh nutrients were supplied. Depletion of p130/Rb2 reduced the G0 fraction, increased cell sensitivity to serum-free culture and to cisplatin, and reduced Mirk levels. Mirk contributed to G0 arrest by destabilization of cyclin D1. In TOV21G cells, but not in normal diploid fibroblasts, Mirk depletion led to increased apoptosis and loss of viability. Because Mirk is expressed at low levels in most normal adult tissues, the elevated Mirk protein levels in ovarian cancers may present a novel therapeutic target, in particular for quiescent tumor cells which are difficult to eradicate by conventional therapies targeting dividing cells.
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Affiliation(s)
- Jing Hu
- Pathology Department, Upstate Medical University, State University of New York, Syracuse, New York 13210, USA
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Identification of a role for histone H2B ubiquitylation in noncoding RNA 3'-end formation through mutational analysis of Rtf1 in Saccharomyces cerevisiae. Genetics 2011; 188:273-89. [PMID: 21441211 DOI: 10.1534/genetics.111.128645] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The conserved eukaryotic Paf1 complex regulates RNA synthesis by RNA polymerase II at multiple levels, including transcript elongation, transcript termination, and chromatin modifications. To better understand the contributions of the Paf1 complex to transcriptional regulation, we generated mutations that alter conserved residues within the Rtf1 subunit of the Saccharomyces cerevisiae Paf1 complex. Importantly, single amino acid substitutions within a region of Rtf1 that is conserved from yeast to humans, which we termed the histone modification domain, resulted in the loss of histone H2B ubiquitylation and impaired histone H3 methylation. Phenotypic analysis of these mutations revealed additional defects in telomeric silencing, transcription elongation, and prevention of cryptic initiation. We also demonstrated that amino acid substitutions within the Rtf1 histone modification domain disrupt 3'-end formation of snoRNA transcripts and identify a previously uncharacterized regulatory role for the histone H2B K123 ubiquitylation mark in this process. Cumulatively, our results reveal functionally important residues in Rtf1, better define the roles of Rtf1 in transcription and histone modification, and provide strong genetic support for the participation of histone modification marks in the termination of noncoding RNAs.
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Bryzgalov LO, Ershov NI, Oshchepkov DY, Kaledin VI, Merkulova TI. Detection of target genes of FOXA transcription factors involved in proliferation control. BIOCHEMISTRY (MOSCOW) 2011; 73:70-5. [DOI: 10.1134/s0006297908010100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Friedman E. The Kinase Mirk/dyrk1B: A Possible Therapeutic Target in Pancreatic Cancer. Cancers (Basel) 2010; 2:1492-512. [PMID: 24281169 PMCID: PMC3837318 DOI: 10.3390/cancers2031492] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 06/28/2010] [Accepted: 07/08/2010] [Indexed: 12/18/2022] Open
Abstract
Pancreatic ductal adenocarcinomas are strongly resistant to chemotherapeutic drugs and radiation, underscoring the need for new therapeutic targets, particularly ones which target the numerous out of cycle cancer cells. Analysis of resected tumors for nuclear Ki67 antigen has shown that about 70% of pancreatic cancer cells are out of cycle, some post-mitotic. Other out of cycle cells are in a quiescent, reversible G0 state, resistant to drugs which target dividing cells, with some able to repopulate a tumor. The serine/threonine kinase Mirk/dyrk1B is a downstream effector of oncogenic K-ras, the most common mutation in this cancer. Mirk expression is elevated in quiescent pancreatic cancer cells and mediates their prolonged survival through increasing expression of a cohort of antioxidant genes. Mirk is expressed in about 90% of pancreatic cancers and is amplified in a subset. Mirk appears not to be an essential gene for normal cells from embryonic knockout studies in mice and RNA interference studies on cultured cells, but is upregulated in pancreatic tumor cells. These unusual characteristics suggest that Mirk may be a selective target for therapeutic intervention.
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Affiliation(s)
- Eileen Friedman
- Upstate Medical University, State University of New York, Syracuse, New York, NY 13210, USA.
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Kuuselo R, Simon R, Karhu R, Tennstedt P, Marx AH, Izbicki JR, Yekebas E, Sauter G, Kallioniemi A. 19q13 amplification is associated with high grade and stage in pancreatic cancer. Genes Chromosomes Cancer 2010; 49:569-75. [PMID: 20232484 DOI: 10.1002/gcc.20767] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Pancreatic cancer is a devastating disease with an extremely poor prognosis, and thus, there is a great need for better diagnostic and therapeutic tools. The 19q13 chromosomal locus is amplified in several cancer types, including pancreatic cancer, but the possible clinical significance of this aberration remains unclear. We used fluorescence in situ hybridization on tissue microarrays containing 357 primary pancreatic tumors, 151 metastases, and 24 local recurrences as well as 120 cancer cell lines from various tissues to establish the frequency of the 19q13 amplification and to find potential correlations to clinical parameters including patient survival. Copy number increases were found in 12.2% of the primary pancreatic tumors and 9.3% of the cell lines, including those derived from bladder, colorectal, ovarian, and thyroid carcinomas. Copy number changes were linked to high grade (P = 0.044) and stage (P = 0.025) tumors, and the average survival time of patients with 19q13 amplification was shorter than that of those without this aberration. Our findings revealed recurrent 19q13 amplification in pancreatic cancer and involvement of the same locus as in bladder, colorectal, ovarian, and thyroid carcinomas. More importantly, the 19q13 amplifications were associated with poor tumor phenotype and showed a trend toward shorter survival.
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Affiliation(s)
- Riina Kuuselo
- Laboratory of Cancer Genetics, Institute of Medical Technology, University of Tampere, Finland
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48
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Muntean AG, Tan J, Sitwala K, Huang Y, Bronstein J, Connelly JA, Basrur V, Elenitoba-Johnson KSJ, Hess JL. The PAF complex synergizes with MLL fusion proteins at HOX loci to promote leukemogenesis. Cancer Cell 2010; 17:609-21. [PMID: 20541477 PMCID: PMC2888888 DOI: 10.1016/j.ccr.2010.04.012] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 02/03/2010] [Accepted: 04/15/2010] [Indexed: 11/23/2022]
Abstract
MLL is involved in chromosomal rearrangements that generate fusion proteins with deregulated transcriptional activity. The mechanisms of MLL fusion protein-mediated transcriptional activation are poorly understood. Here we show MLL interacts directly with the polymerase associated factor complex (PAFc) through sequences flanking the CxxC domain. PAFc interacts with RNA polymerase II and stimulates posttranslational histone modifications. PAFc augments MLL and MLL-AF9 mediated transcriptional activation of Hoxa9. Conversely, knockdown of PAFc disrupts MLL fusion protein-mediated transcriptional activation and MLL recruitment to target loci. PAFc gene expression is downregulated during hematopoiesis and likely serves to regulate MLL function. Deletions of MLL that abolish interactions with PAFc also eliminate MLL-AF9 mediated immortalization indicating an essential function for this interaction in leukemogenesis.
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Affiliation(s)
- Andrew G. Muntean
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Jiaying Tan
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Kajal Sitwala
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yongsheng Huang
- Department of Statistics, Center for Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Joel Bronstein
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - James A. Connelly
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Venkatesha Basrur
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | | | - Jay L. Hess
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Corresponding Author: Jay L. Hess M.D. Ph.D. M5240 Medical Sciences I, 1301 Catherine Avenue, Ann Arbor, MI 48109-0602, Phone: (734) 763-6384, Fax: (734) 763-4782,
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Ponnusamy MP, Deb S, Dey P, Chakraborty S, Rachagani S, Senapati S, Batra SK. RNA polymerase II associated factor 1/PD2 maintains self-renewal by its interaction with Oct3/4 in mouse embryonic stem cells. Stem Cells 2010; 27:3001-11. [PMID: 19821493 DOI: 10.1002/stem.237] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Embryonic stem cells (ESCs) maintain self-renewal while ensuring a rapid response to differentiation signals, but the exact mechanism of this process remains unknown. PD2 is the human homolog of the RNA polymerase II-associated factor 1 (Paf1). The Paf1/PD2 is a member of the human PAF complex that consists of four other subunits, hCdc73, hLeo1, hCtr9, and hSki8, and is involved in the regulation of transcriptional elongation and further downstream events. Here, we show that Paf1/PD2 is overexpressed in mouse ESCs and is involved in the maintenance of mouse ESCs. The Paf1/PD2 knockdown and knockout ESCs grown under self-renewal conditions express substantially reduced levels of self-renewal regulators, including Oct3/4, SOX2, Nanog, and Shh. We observed that the level of Paf1/PD2 expression is much higher in self-renewing mouse embryonic carcinoma cells than in the differentiating cells. Knockout of Paf1/PD2 altered ESC phenotype by increasing apoptosis and decreasing the percentage of cells in S-phase of the cell cycle. Interestingly, we found that the key genes that regulate endodermal differentiation (Gata4, Gata6, and Fgf8) are induced in the Paf1/PD2 heterozygous knockout ESCs. This suggests that Paf1/PD2 plays a specific role in regulating early commitment of ESCs to endodermal differentiation. Furthermore, for the first time, we showed that Paf1/PD2 protein interacts with Oct3/4 and RNA polymerase II, and through this interaction Paf1/PD2 may regulate Oct3/4-mediated gene expression. Thus, the Paf1/PD2 protein is a newly discovered element of the interconnected regulatory network that maintains the self-renewal of mouse ESCs.
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Affiliation(s)
- Moorthy P Ponnusamy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870, USA
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50
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Zhang Y, Smith AD, Renfrow MB, Schneider DA. The RNA polymerase-associated factor 1 complex (Paf1C) directly increases the elongation rate of RNA polymerase I and is required for efficient regulation of rRNA synthesis. J Biol Chem 2010; 285:14152-9. [PMID: 20299458 DOI: 10.1074/jbc.m110.115220] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The rate of ribosome synthesis is proportional to the rate of cell proliferation; thus, transcription of rRNA by RNA polymerase I (Pol I) is an important target for the regulation of this process. Most previous investigations into mechanisms that regulate the rate of ribosome synthesis have focused on the initiation step of transcription by Pol I; however, recent studies in yeast and mammals have identified factors that influence transcription elongation by Pol I. The RNA polymerase-associated factor 1 complex (Paf1C) is a transcription elongation factor with known roles in Pol II transcription. We previously identified a role for Paf1C in transcription elongation by Pol I. In this study, genetic interactions between genes for Paf1C and Pol I subunits confirm this conclusion. In vitro studies demonstrate that purified Paf1C directly increases the rate of transcription elongation by Pol I. Finally, we show that Paf1C function is required for efficient control of Pol I transcription in response to target of rapamycin (TOR) signaling or amino acid limitation. These studies demonstrate that Paf1C plays an important direct role in cellular control of rRNA expression.
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Affiliation(s)
- Yinfeng Zhang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294-0024, USA
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