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Ren M, Yang Y, Heng KHY, Ng LY, Chong CYY, Ng YT, Gorur-Shandilya S, Lee RMQ, Lim KL, Zhang J, Koh TW. MED13 and glycolysis are conserved modifiers of α-synuclein-associated neurodegeneration. Cell Rep 2022; 41:111852. [PMID: 36543134 DOI: 10.1016/j.celrep.2022.111852] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 10/04/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022] Open
Abstract
α-Synuclein (α-syn) is important in synucleinopathies such as Parkinson's disease (PD). While genome-wide association studies (GWASs) of synucleinopathies have identified many risk loci, the underlying genes have not been shown for most loci. Using Drosophila, we screened 3,471 mutant chromosomes for genetic modifiers of α-synuclein and identified 12 genes. Eleven modifiers have human orthologs associated with diseases, including MED13 and CDC27, which lie within PD GWAS loci. Drosophila Skd/Med13 and glycolytic enzymes are co-upregulated by α-syn-associated neurodegeneration. While elevated α-syn compromises mitochondrial function, co-expressing skd/Med13 RNAi and α-syn synergistically increase the ratio of oxidized-to-reduced glutathione. The resulting neurodegeneration can be suppressed by overexpressing a glycolytic enzyme or treatment with deferoxamine, suggesting that compensatory glycolysis is neuroprotective. In addition, the functional relationship between α-synuclein, MED13, and glycolytic enzymes is conserved between flies and mice. We propose that hypoxia-inducible factor and MED13 are part of a druggable pathway for PD.
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Affiliation(s)
- Mengda Ren
- Temasek Life Sciences Laboratory, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117558, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308207, Singapore; National Neuroscience Institute, Singapore 308433, Singapore
| | - Ying Yang
- Department of Pathology, Zhejiang University First Affiliated Hospital and School of Medicine, Hangzhou, Zhejiang 310002, China
| | | | - Lu Yi Ng
- Temasek Life Sciences Laboratory, Singapore 117604, Singapore
| | | | - Yan Ting Ng
- Temasek Life Sciences Laboratory, Singapore 117604, Singapore
| | | | - Rachel Min Qi Lee
- Temasek Life Sciences Laboratory, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117558, Singapore
| | - Kah Leong Lim
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308207, Singapore; National Neuroscience Institute, Singapore 308433, Singapore
| | - Jing Zhang
- Department of Pathology, Zhejiang University First Affiliated Hospital and School of Medicine, Hangzhou, Zhejiang 310002, China; China National Health and Disease Human Brain Tissue Resource Center, Hangzhou, Zhejiang 310002, China
| | - Tong-Wey Koh
- Temasek Life Sciences Laboratory, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117558, Singapore.
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Li T, Wu Y, Chen WC, Xue X, Suo MJ, Li P, Sheng W, Huang GY. Functional analysis of HECA variants identified in congenital heart disease in the Chinese population. J Clin Lab Anal 2022; 36:e24649. [PMID: 35949005 PMCID: PMC9459261 DOI: 10.1002/jcla.24649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/13/2022] [Accepted: 07/26/2022] [Indexed: 11/07/2022] Open
Abstract
Background Congenital heart disease (CHD) is a class of cardiovascular defects that includes septal defects, outflow tract abnormalities, and valve defects. Human homolog of Drosophila headcase (HECA) is a novel cell cycle regulator whose role in CHD has not been elucidated. This is the first study to determine the frequency of HECA mutations in patients with CHD and the association between HECA variants and CHD. Methods In this study, we identified a candidate gene, HECA, by whole‐exome sequencing of an atrial septal defect family. To investigate the association between HECA variants and CHD risk, targeted exon sequencing was conducted in 689 individuals with sporadic CHD. We further analyzed the effect of HECA gene abnormalities on cardiomyocyte phenotype behavior and related signaling pathways by Western blotting, reverse transcription‐quantitative polymerase chain reaction, and scratch assay. Results We found a novel de novo mutation, c.409_410insA (p. W137fs), in the HECA gene and identified five rare deleterious variants that met the filtering criteria in 689 individuals with sporadic CHD. Fisher's exact test revealed a significant association between HECA variations and CHD compared with those in gnomADv2‐East Asians(p = 0.0027). Further functional analysis suggested that the variant p. W137fs resulted in a deficiency of the normal HECA protein, and HECA deficiency altered AC16 cell cycle progression, increased cell proliferation, and migration, and promoted the activation of the PDGF‐BB/PDGFRB/AKT pathway. Conclusions Our study identified HECA and its six rare variants, expanding the spectrum of genes associated with CHD pathogenesis in the Chinese population.
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Affiliation(s)
- Ting Li
- Children's Hospital of Fudan University, Shanghai, China.,Shanghai Key Laboratory of Birth Defects, Shanghai, China
| | - Yao Wu
- Children's Hospital of Fudan University, Shanghai, China
| | - Wei-Cheng Chen
- Children's Hospital of Fudan University, Shanghai, China.,Shanghai Key Laboratory of Birth Defects, Shanghai, China
| | - Xing Xue
- Children's Hospital of Fudan University, Shanghai, China.,Shanghai Key Laboratory of Birth Defects, Shanghai, China
| | - Mei-Jiao Suo
- Children's Hospital of Fudan University, Shanghai, China.,Shanghai Key Laboratory of Birth Defects, Shanghai, China
| | - Ping Li
- Children's Hospital of Fudan University, Shanghai, China.,Shanghai Key Laboratory of Birth Defects, Shanghai, China
| | - Wei Sheng
- Children's Hospital of Fudan University, Shanghai, China.,Shanghai Key Laboratory of Birth Defects, Shanghai, China
| | - Guo-Ying Huang
- Children's Hospital of Fudan University, Shanghai, China.,Shanghai Key Laboratory of Birth Defects, Shanghai, China.,Research Unit of Early Intervention of Genetically Related Childhood Cardiovascular Diseases(2018RU002), Chinese Academy of Medical Sciences, Shanghai, China
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3
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Marca JEL, Somers WG. The Drosophila gonads: models for stem cell proliferation, self-renewal, and differentiation. AIMS GENETICS 2021. [DOI: 10.3934/genet.2014.1.55] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AbstractThe male and female gonads of Drosophila melanogaster have developed into powerful model systems for both the study of stem cell behaviours, and for understanding how stem cell misregulation can lead to cancers. Using these systems, one is able to observe and manipulate the resident stem cell populations in vivo with a great deal of licence. The tractability of the testis and ovary also allow researchers to explore a range of cellular mechanisms, such as proliferation and polarity, as well as the influence exerted by the local environment through a host of highly-conserved signalling pathways. Importantly, many of the cellular behaviours and processes studied in the Drosophila testis and ovary are known to be disrupted, or otherwise misregulated, in human tumourigenic cells. Here, we review the mechanisms relating to stem cell behaviour, though we acknowledge there are many other fascinating aspects of gametogenesis, including the invasive behaviour of migratory border cells in the Drosophila ovary that, though relevant to the study of tumourigenesis, will unfortunately not be covered.
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Affiliation(s)
- John E. La Marca
- Department of Genetics, La Trobe University, Melbourne, VIC 3086, Australia
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Giannios P, Casanova J. Systemic and local effect of the Drosophila headcase gene and its role in stress protection of Adult Progenitor Cells. PLoS Genet 2021; 17:e1009362. [PMID: 33556132 PMCID: PMC7895379 DOI: 10.1371/journal.pgen.1009362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/19/2021] [Accepted: 01/13/2021] [Indexed: 12/17/2022] Open
Abstract
During the development of a holometabolous insect such as Drosophila, specific group of cells in the larva survive during metamorphosis, unlike the other larval cells, and finally give rise to the differentiated adult structures. These cells, also known as Adult Progenitor Cells (APCs), maintain their multipotent capacity, differentially respond to hormonal and nutritional signals, survive the intrinsic and environmental stress and respond to the final differentiation cues. However, not much is known about the specific molecular mechanisms that account for their unique characteristics. Here we show that a specific Drosophila APC gene, headcase (hdc), has a dual role in the normal development of these cells. It acts at a systemic level by controlling the hormone ecdysone in the prothoracic gland and at the same time it acts locally as a tissue growth suppressor in the APC clusters, where it modulates the activity of the TOR pathway and promotes their survival by contributing in the regulation of the Unfolded Protein Response. We also show that hdc provides protection against stress in the APCs and that its ectopic expression in cells that do not usually express hdc can confer these cells with an additional stress protection. Hdc is the founding member of a group of homolog proteins identified from C. elegans to humans, where has been found associated with cancer progression. The finding that the Drosophila hdc is specifically expressed in progenitor cells and that it provides protection against stress opens up a new hypothesis to be explored regarding the role of the human Heca and its contribution to carcinogenesis.
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Affiliation(s)
- Panagiotis Giannios
- Institut de Biologia Molecular de Barcelona (CSIC), Barcelona, Catalonia, Spain
- Institut de Recerca Biomèdica de Barcelona, (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
| | - Jordi Casanova
- Institut de Biologia Molecular de Barcelona (CSIC), Barcelona, Catalonia, Spain
- Institut de Recerca Biomèdica de Barcelona, (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
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5
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Li N, Liu Q, Xiong Y, Yu J. Headcase and Unkempt Regulate Tissue Growth and Cell Cycle Progression in Response to Nutrient Restriction. Cell Rep 2020; 26:733-747.e3. [PMID: 30650363 PMCID: PMC6350942 DOI: 10.1016/j.celrep.2018.12.086] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/24/2018] [Accepted: 12/19/2018] [Indexed: 11/26/2022] Open
Abstract
Nutrient restriction (NR) decreases the incidence and growth of many types of tumors, yet the underlying mechanisms are not fully understood. In this study, we identified Headcase (Hdc) and Unkempt (Unk) as two NR-specific tumor suppressor proteins that form a complex to restrict cell cycle progression and tissue growth in response to NR in Drosophila. Loss of Hdc or Unk does not confer apparent growth advantage under normal nutrient conditions but leads to accelerated cell cycle progression and tissue overgrowth under NR. Hdc and Unk bind to the TORC1 component Raptor and preferentially regulate S6 phosphorylation in a TORC1-dependent manner. We further show that HECA and UNK, the human counterparts of Drosophila Hdc and Unk, respectively, have a conserved function in regulating S6 phosphorylation and tissue growth. The identification of Hdc and Unk as two NR-specific tumor suppressors provides insight into molecular mechanisms underlying the anti-tumorigenic effects of NR. The molecular mechanisms underlying nutrient restriction resistance remain unclear. Li et al. find that Hdc and Unk function in the mTOR signaling pathway to restrict tissue growth and cell cycle progression in response to nutrient restriction.
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Affiliation(s)
- Naren Li
- Department of Anatomy & Physiology, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA
| | - Qinfang Liu
- Department of Anatomy & Physiology, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA
| | - Yulan Xiong
- Department of Anatomy & Physiology, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA.
| | - Jianzhong Yu
- Department of Anatomy & Physiology, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA.
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6
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Son HJ, Choi EJ, Yoo NJ, Lee SH. Mutational and expressional alterations of a candidate tumor suppressor HECA gene in gastric and colorectal cancers. Pathol Res Pract 2020; 216:152896. [PMID: 32088090 DOI: 10.1016/j.prp.2020.152896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 02/16/2020] [Indexed: 11/25/2022]
Affiliation(s)
- Hyun Ji Son
- Departments of Pathology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Eun Ji Choi
- Departments of Pathology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Nam Jin Yoo
- Departments of Pathology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Sug Hyung Lee
- Departments of Pathology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea; Cancer Research Institute, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
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7
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Wang J, Gong L, Zhu SJ, Zhu Q, Yao L, Han XJ, Zhang JR, Li YH, Zhang W. The Human Homolog of Drosophila Headcase Acts as a Tumor Suppressor through Its Blocking Effect on the Cell Cycle in Hepatocellular Carcinoma. PLoS One 2015; 10:e0137579. [PMID: 26356417 PMCID: PMC4565651 DOI: 10.1371/journal.pone.0137579] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/18/2015] [Indexed: 12/22/2022] Open
Abstract
The molecular pathogenesis of hepatocellular carcinoma (HCC) is heterogeneous and extremely complex. Thus, for individual molecular targeted therapy, novel molecular markers are needed. The abnormal expression of the human homolog of Drosophila headcase (HECA homo) has been found in pancreatic, colorectal, and oral squamous cell carcinoma. Studies of oral squamous cell carcinoma have also demonstrated that the HECA homo protein can be negatively controlled by the Wnt-pathway and transcription factor 4 (TCF4) and can slow cell division by interacting with cyclins and CDKs. However, the role of HECA in HCC has not been reported elsewhere. Here, immunohistochemical analysis revealed that the downregulation of HECA homo protein occurred in 71.0% (66/93) of HCC cases and was positively correlated with a poorly differentiated grade, high serum AFP level, liver cirrhosis and large tumor size. The expression of HECA homo was detected in five live cell lines. In vitro, the overexpression of HECA homo in HepG2, Huh-7 and MHCC-97H cells could inhibit cell proliferation and colony formation and induce G1 phase arrest. In contrast, the downregulation of HECA homo could promote cell proliferation, colony formation and the cell cycle process. However, neither the overexpression nor downregulation of HECA homo in the three cell lines could affect cell migration or invasion. Collectively, HECA homo is regularly expressed in normal live cells, and the HECA homo protein level is heterogeneously altered in HCC, but the downregulation of HECA homo is more common and positively correlated with several malignant phenotypes. The HECA homo protein can slow cell proliferation to some extent primarily through its blocking effect on the cell cycle. Hence, the HECA homo protein may act as a tumor suppressor in HCC and might be a potential molecular marker for diagnostic classification and targeted therapy in HCC.
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Affiliation(s)
- Jun Wang
- The Helmholtz Sino-German Laboratory for Cancer Research, Department of Pathology, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Li Gong
- The Helmholtz Sino-German Laboratory for Cancer Research, Department of Pathology, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Shao-Jun Zhu
- The Helmholtz Sino-German Laboratory for Cancer Research, Department of Pathology, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Qiao Zhu
- The Helmholtz Sino-German Laboratory for Cancer Research, Department of Pathology, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Li Yao
- The Helmholtz Sino-German Laboratory for Cancer Research, Department of Pathology, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Xiu-Juan Han
- The Helmholtz Sino-German Laboratory for Cancer Research, Department of Pathology, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Jia-Rui Zhang
- The Helmholtz Sino-German Laboratory for Cancer Research, Department of Pathology, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Yan-Hong Li
- The Helmholtz Sino-German Laboratory for Cancer Research, Department of Pathology, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
- Department of Gynecology and Obstetrics, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
- * E-mail: (WZ); (Y-HL)
| | - Wei Zhang
- The Helmholtz Sino-German Laboratory for Cancer Research, Department of Pathology, Tangdu Hospital, The Fourth Military Medical University, Xi’an, Shaanxi, China
- * E-mail: (WZ); (Y-HL)
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8
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Abstract
Large-scale pruning, the removal of long neuronal processes, is deployed widely within the developing nervous system and is essential for proper circuit formation. In Drosophila the dendrites of the class IV dendritic arborization sensory neuron ddaC undergo large-scale pruning by local degeneration controlled by the steroid hormone ecdysone. The molecular mechanisms that control such events are largely unknown. To identify new molecules that orchestrate this developmental degeneration, we performed a genetic interaction screen. Our approach combines the strength of Drosophila forward genetics with detailed in vivo imaging of ddaC neurons. This screen allowed us to identify headcase (hdc) as a new gene involved in dendrite pruning. hdc is evolutionarily conserved, but the protein's function is unknown. Here we show that hdc is expressed just before metamorphosis in sensory neurons that undergo remodeling. hdc is required in a cell-autonomous manner to control dendrite severing, the first phase of pruning. Our epistasis experiments with known regulators of dendrite pruning reveal hdc as a founding member of a new pathway downstream of ecdysone signaling.
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Dowejko A, Bauer RJ, Müller-Richter UDA, Reichert TE. The human homolog of the Drosophila headcase protein slows down cell division of head and neck cancer cells. Carcinogenesis 2009; 30:1678-85. [PMID: 19643820 DOI: 10.1093/carcin/bgp189] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The human homolog of the Drosophila headcase (HECA) belongs to a new class of cell differentiation regulators. In Drosophila, the HECA protein regulates the proliferation and differentiation of cells during adult morphogenesis. There is growing evidence that HECA plays an important role in human carcinogenesis. In different tumor entities, an altered HECA expression was found (colorectal, pancreatic and renal cancer). Colorectal cancer studies also suggested HECA as a marker for early disease stages. Therefore, we speculated whether human HECA affects cell cycle progression and proliferation in head and neck cancer cells. In vivo, we found a distinct HECA protein expression in basal and superficial cells of a healthy oral epithelium via immunohistochemistry, whereas in tissues of oral squamous cell carcinoma (OSCC), a weaker staining was observed, particularly in basal cells. In vitro, mRNA and protein expression analyses of OSCC cell lines exhibited that HECA expression correlates with the state of cellular differentiation. In further investigations, we overexpressed HECA in the OSCC cell line PCI 13 and performed functional assays. HECA-overexpressing OSCC cells revealed a significant extended doubling time (up to 45%, 17 h) and yielded a lower number of proliferating cells (up to 30%) than controls. Flow cytometry analyses have shown that HECA-overexpressing OSCC cells forced to hold in the G(2)/M-Phase. In summary, our results show that human HECA slows down cell division of OSCC cells and may therefore act as a tumor suppressor in head and neck cancer.
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Affiliation(s)
- Albert Dowejko
- Department of Oral and Maxillofacial Surgery, University of Regensburg, Regensburg, Germany.
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10
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Systematic identification of genes that regulate neuronal wiring in the Drosophila visual system. PLoS Genet 2008; 4:e1000085. [PMID: 18516287 PMCID: PMC2377342 DOI: 10.1371/journal.pgen.1000085] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Accepted: 04/30/2008] [Indexed: 11/19/2022] Open
Abstract
Forward genetic screens in model organisms are an attractive means to identify those genes involved in any complex biological process, including neural circuit assembly. Although mutagenesis screens are readily performed to saturation, gene identification rarely is, being limited by the considerable effort generally required for positional cloning. Here, we apply a systematic positional cloning strategy to identify many of the genes required for neuronal wiring in the Drosophila visual system. From a large-scale forward genetic screen selecting for visual system wiring defects with a normal retinal pattern, we recovered 122 mutations in 42 genetic loci. For 6 of these loci, the underlying genetic lesions were previously identified using traditional methods. Using SNP-based mapping approaches, we have now identified 30 additional genes. Neuronal phenotypes have not previously been reported for 20 of these genes, and no mutant phenotype has been previously described for 5 genes. The genes encode a variety of proteins implicated in cellular processes such as gene regulation, cytoskeletal dynamics, axonal transport, and cell signalling. We conducted a comprehensive phenotypic analysis of 35 genes, scoring wiring defects according to 33 criteria. This work demonstrates the feasibility of combining large-scale gene identification with large-scale mutagenesis in Drosophila, and provides a comprehensive overview of the molecular mechanisms that regulate visual system wiring.
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Hui ABY, Takano H, Lo KW, Kuo WL, Lam CNY, Tong CYK, Chang Q, Gray JW, Ng HK. Identification of a novel homozygous deletion region at 6q23.1 in medulloblastomas using high-resolution array comparative genomic hybridization analysis. Clin Cancer Res 2005; 11:4707-16. [PMID: 16000565 DOI: 10.1158/1078-0432.ccr-05-0128] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The aim of this study is to comprehensively characterize genome copy number aberrations in medulloblastomas using high-resolution array comparative genomic hybridization. EXPERIMENTAL DESIGN High-density genomic arrays containing 1,803 BAC clones were used to define recurrent chromosomal regions of gains or losses throughout the whole genome of medulloblastoma. A series of 3 medulloblastoma cell lines and 16 primary tumors were investigated. RESULTS The detected consistent chromosomal aberrations included gains of 1q21.3-q23.1 (36.8%), 1q32.1 (47.4%), 2p23.1-p25.3 (52.6%), 7 (57.9%), 9q34.13-q34.3 (47.4%), 17p11.2-q25.3 (89.5%), and 20q13.31-q13.33 (42.1%), as well as losses of 3q26.1 (57.9%), 4q31.23-q32.3 (42.1%), 6q23.1-25.3 (57.9%), 8p22-23.3 (79%), 10q24.32-26.2 (57.9%), and 16q23.2-q24.3 (63.2%). One of the most notable aberrations was a homozygous deletion on chromosome 6q23 in the cell line DAOY, and single copy loss on 30.3% primary tumors. Further analyses defined a 0.887 Mbp minimal region of homozygous deletion at 6q23.1 flanked by markers SHGC-14149 (6q22.33) and SHGC-110551 (6q23.1). Quantitative reverse transcription-PCR analysis showed complete loss of expression of two genes located at 6q23.1, AK091351 (hypothetical protein FLJ34032) and KIAA1913, in the cell line DAOY. mRNA levels of these genes was reduced in cell lines D283 and D384, and in 50% and 70% of primary tumors, respectively. CONCLUSION Current array comparative genomic hybridization analysis generates a comprehensive pattern of chromosomal aberrations in medulloblastomas. This information will lead to a better understanding of medulloblastoma tumorigenesis. The delineated regions of gains or losses will indicate locations of medulloblastoma-associated genes. A 0.887 Mbp homozygous deletion region was newly identified at 6q23.1. Frequent detection of reduced expression of AK091351 and KIAA1913 genes implicates them as suppressors of medulloblastoma tumorigenesis.
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Affiliation(s)
- Angela B Y Hui
- Department of Anatomical and Cellular Pathology, Chinese University of Hong Kong, Hong Kong SAR, PR China
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Fujii H, Gabrielson E, Takagaki T, Ohtsuji M, Ohtsuji N, Hino O. Frequent down-regulation of HIVEP2 in human breast cancer. Breast Cancer Res Treat 2005; 91:103-12. [PMID: 15868437 DOI: 10.1007/s10549-004-5779-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The HIVEP2 gene, located on 6q23-q24, belongs to a family of genes that encodes large zinc fingers containing transcription factor proteins. Although this gene has been implicated in the regulation of immune responses and cellular proliferation, its functions are largely unknown. In the present study, we investigated HIVEP2 gene abnormalities in microdissected breast cancer tissue. For real-time quantitational RT-PCR analysis of paired normal and tumor tissues, mRNA levels were down-regulated to a maximum of 96%. The overall median expression level in breast cancer (33 cases) was significantly lower than that in normal breast tissue (normalized median value of 4.49 versus 17.68; p < 0.0001). Through full-length 5'-RACE (rapid amplification of cDNA ends) analysis, we identified multiple exons in the 5'-untranslated regions with multiple transcriptional start sites, four of which were located in a large CpG island. No tissue- or cancer-specific usage patterns for the transcription start sites were identified by multiplex RT-PCR analysis. Only faint methylation was detected in the 5' region of the island in normal cells and breast cancer tissue, indicating physiological, aging and no tumor-specific methylation. Mutation screening showed only germline polymorphisms. Thus, down-regulation of the HIVEP2 genes frequently occurs and may be one of the genetic events responsible for breast cancer, and their transcription may be regulated by complex mechanisms involving interactions with other factors and/or by other genetic/epigenetic mechanisms.
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Affiliation(s)
- Hiroaki Fujii
- Department of Pathology II, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan.
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13
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Abstract
To find molecular clues useful for early detection and effective therapy for pancreatic cancer, we first carried out genomic analysis by means of comparative genomic hybridization and micro-satellite analysis. We found very complicated molecular alterations in multiple chromosomal regions, including 1p, 6q, 9p, 12q, 17p, 18q, and 21q for losses and 8q and 20q for gains. These diverse changes are very characteristic of pancreatic cancer, and from this information, we developed a method for detecting the aberrant copy numbers of specific chromosomal regions by fluorescence in situ hybridization in cells collected from pancreatic juice for early diagnosis of pancreatic neoplasms. The regions of losses suggest the existence of tumor suppressor genes (TSGs). We identified DUSP6/MKP-3 at 12q21-q22 as a strong candidate TSG; it showed epigenetic inactivation in some fractions of invasive pancreatic cancer and growth suppression and apoptosis by overexpression in vitro. To determine the pathologic roles of 18q, we introduced a normal copy of chromosome 18 into cultured pancreatic cancer cells. The introduction induced marked suppressions of tumor formation and metastasis formation in vivo. We continue work to more completely understand the complex molecular mechanisms of pancreatic carcinogenesis and to apply the information gained to the clinical treatment of pancreatic cancer.
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Affiliation(s)
- Toru Furukawa
- Department of Molecular Pathology, Tohoku University School of Medicine, Sendai, Miyagi, Japan.
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Sun HS, Su IJ, Lin YC, Chen JS, Fang SY. A 2.6 Mb interval on chromosome 6q25.2-q25.3 is commonly deleted in human nasal natural killer/T-cell lymphoma. Br J Haematol 2003; 122:590-9. [PMID: 12899714 DOI: 10.1046/j.1365-2141.2003.04419.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Natural killer (NK)/T-cell lymphoma is a special subtype of rare malignant lymphoma that is more prevalent in Asia than in America and Europe. This newly characterized haemato-lymphoid malignancy is highly aggressive and frequently present in nasal and upper aerodigestive sites. Several studies have reported the commonly deleted region of chromosome 6q21-25 in this particular type of lymphoma. To refine the smallest region of overlapping (SRO) deletion for localization of potential tumour suppressor (TS) genes, we performed loss of heterozygosity (LOH) and homozygosity mapping of deletion (HOMOD) analyses on 37 nasal and nasal-type NK/T-cell lymphoma patients using a panel of 25 microsatellite markers, covering the 6q21-q25 region. In all patients studied, LOH was detected in eight (89%) paired-sample patients, while hemizygous deletion was detected in three (11%) single-sample patients. Combination of the LOH and HOMOD results defined a distinct 3 Mb SRO on chromosome 6q25. Quantitative multiplex polymerase chain reaction analysis of 10 sequence-tagged sites further refined the putative TS-gene-containing region to a 2.6 Mb interval between TIAM2 and SNX9. Eighteen known genes/Unigene clusters and 25 hypothetical genes are located within this 2.6 Mb region, but none are previously identified TS genes. These results provide a framework for future positional cloning of novel TS gene(s) at 6q25.2-q25.3.
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Affiliation(s)
- H Sunny Sun
- Institute of Molecular Medicine, National Cheng Kung University Medical College, 1 University Road, Tainan 70101, Taiwan, ROC.
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