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Mehraj U, Ganai RA, Macha MA, Hamid A, Zargar MA, Bhat AA, Nasser MW, Haris M, Batra SK, Alshehri B, Al-Baradie RS, Mir MA, Wani NA. The tumor microenvironment as driver of stemness and therapeutic resistance in breast cancer: New challenges and therapeutic opportunities. Cell Oncol (Dordr) 2021; 44:1209-1229. [PMID: 34528143 DOI: 10.1007/s13402-021-00634-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2021] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Breast cancer (BC), the second most common cause of cancer-related deaths, remains a significant threat to the health and wellness of women worldwide. The tumor microenvironment (TME), comprising cellular components, such as cancer-associated fibroblasts (CAFs), immune cells, endothelial cells and adipocytes, and noncellular components such as extracellular matrix (ECM), has been recognized as a critical contributor to the development and progression of BC. The interplay between TME components and cancer cells promotes phenotypic heterogeneity, cell plasticity and cancer cell stemness that impart tumor dormancy, enhanced invasion and metastasis, and the development of therapeutic resistance. While most previous studies have focused on targeting cancer cells with a dismal prognosis, novel therapies targeting stromal components are currently being evaluated in preclinical and clinical studies, and are already showing improved efficacies. As such, they may offer better means to eliminate the disease effectively. CONCLUSIONS In this review, we focus on the evolving concept of the TME as a key player regulating tumor growth, metastasis, stemness, and the development of therapeutic resistance. Despite significant advances over the last decade, several clinical trials focusing on the TME have failed to demonstrate promising effectiveness in cancer patients. To expedite clinical efficacy of TME-directed therapies, a deeper understanding of the TME is of utmost importance. Secondly, the efficacy of TME-directed therapies when used alone or in combination with chemo- or radiotherapy, and the tumor stage needs to be studied. Likewise, identifying molecular signatures and biomarkers indicating the type of TME will help in determining precise TME-directed therapies.
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Affiliation(s)
- Umar Mehraj
- Department of Bioresources, University of Kashmir, Srinagar, Jammu & Kashmir, India
| | - Rais A Ganai
- Watson-Crick Centre for Molecular Medicine, Islamic University of Science & Technology , Awantipora, Jammu & Kashmir, India
| | - Muzafar A Macha
- Watson-Crick Centre for Molecular Medicine, Islamic University of Science & Technology , Awantipora, Jammu & Kashmir, India
| | - Abid Hamid
- Department of Biotechnology, School of Life Sciences, Central University of Kashmir, Ganderbal, J&K, India
| | - Mohammed A Zargar
- Department of Biotechnology, School of Life Sciences, Central University of Kashmir, Ganderbal, J&K, India
| | - Ajaz A Bhat
- Translational Medicine, Research Branch, Sidra Medicine, Doha, Qatar
| | - Mohd Wasim Nasser
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Mohammad Haris
- Translational Medicine, Research Branch, Sidra Medicine, Doha, Qatar.,Laboratory of Animal Research, Qatar University, Doha, Qatar
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.,Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska, Lincoln, NE, USA.,Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Bader Alshehri
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Almajmaah, Kingdom of Saudi Arabia
| | - Raid Saleem Al-Baradie
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Almajmaah, Kingdom of Saudi Arabia
| | - Manzoor A Mir
- Department of Bioresources, University of Kashmir, Srinagar, Jammu & Kashmir, India.
| | - Nissar Ahmad Wani
- Department of Biotechnology, School of Life Sciences, Central University of Kashmir, Ganderbal, J&K, India.
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Raina A, Sahu PK, Laskar RA, Rajora N, Sao R, Khan S, Ganai RA. Mechanisms of Genome Maintenance in Plants: Playing It Safe With Breaks and Bumps. Front Genet 2021; 12:675686. [PMID: 34239541 PMCID: PMC8258418 DOI: 10.3389/fgene.2021.675686] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/04/2021] [Indexed: 01/14/2023] Open
Abstract
Maintenance of genomic integrity is critical for the perpetuation of all forms of life including humans. Living organisms are constantly exposed to stress from internal metabolic processes and external environmental sources causing damage to the DNA, thereby promoting genomic instability. To counter the deleterious effects of genomic instability, organisms have evolved general and specific DNA damage repair (DDR) pathways that act either independently or mutually to repair the DNA damage. The mechanisms by which various DNA repair pathways are activated have been fairly investigated in model organisms including bacteria, fungi, and mammals; however, very little is known regarding how plants sense and repair DNA damage. Plants being sessile are innately exposed to a wide range of DNA-damaging agents both from biotic and abiotic sources such as ultraviolet rays or metabolic by-products. To escape their harmful effects, plants also harbor highly conserved DDR pathways that share several components with the DDR machinery of other organisms. Maintenance of genomic integrity is key for plant survival due to lack of reserve germline as the derivation of the new plant occurs from the meristem. Untowardly, the accumulation of mutations in the meristem will result in a wide range of genetic abnormalities in new plants affecting plant growth development and crop yield. In this review, we will discuss various DNA repair pathways in plants and describe how the deficiency of each repair pathway affects plant growth and development.
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Affiliation(s)
- Aamir Raina
- Mutation Breeding Laboratory, Department of Botany, Aligarh Muslim University, Aligarh, India
- Botany Section, Women’s College, Aligarh Muslim University, Aligarh, India
| | - Parmeshwar K. Sahu
- Department of Genetics and Plant Breeding, Indira Gandhi Agriculture University, Raipur, India
| | | | - Nitika Rajora
- National Agri-Food Biotechnology Institute, Mohali, India
| | - Richa Sao
- Department of Genetics and Plant Breeding, Indira Gandhi Agriculture University, Raipur, India
| | - Samiullah Khan
- Mutation Breeding Laboratory, Department of Botany, Aligarh Muslim University, Aligarh, India
| | - Rais A. Ganai
- Watson-Crick Centre for Molecular Medicine, Islamic University of Science and Technology, Awantipora, India
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LeRoy G, Oksuz O, Descostes N, Aoi Y, Ganai RA, Kara HO, Yu JR, Lee CH, Stafford J, Shilatifard A, Reinberg D. LEDGF and HDGF2 relieve the nucleosome-induced barrier to transcription in differentiated cells. Sci Adv 2019; 5:eaay3068. [PMID: 31616795 PMCID: PMC6774727 DOI: 10.1126/sciadv.aay3068] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/05/2019] [Indexed: 05/25/2023]
Abstract
FACT (facilitates chromatin transcription) is a protein complex that allows RNA polymerase II (RNAPII) to overcome the nucleosome-induced barrier to transcription. While abundant in undifferentiated cells and many cancers, FACT is not abundant or is absent in most tissues. Therefore, we screened for additional proteins that might replace FACT upon differentiation. We identified two proteins, lens epithelium-derived growth factor (LEDGF) and hepatoma-derived growth factor 2 (HDGF2), each containing two high mobility group A (HMGA)-like AT-hooks and a methyl-lysine reading Pro-Trp-Trp-Pro (PWWP) domain that binds to H3K36me2 and H3K36me3.LEDGF and HDGF2 colocalize with H3K36me2/3 at genomic regions containing active genes. In myoblasts, LEDGF and HDGF2 are enriched on most active genes. Upon differentiation to myotubes, LEDGF levels decrease, while HDGF2 levels are maintained. Moreover, HDGF2 is required for their proper expression. HDGF2 knockout myoblasts exhibit an accumulation of paused RNAPII within the transcribed region of many HDGF2 target genes, indicating a defect in early elongation.
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Affiliation(s)
- Gary LeRoy
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Ozgur Oksuz
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Nicolas Descostes
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
- EMBL Rome, Adriano Buzzati-Traverso Campus, Via Ramarini 32, 00015 Monterotondo (RM), Italy
| | - Yuki Aoi
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Rais A. Ganai
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Havva Ortabozkoyun Kara
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Jia-Ray Yu
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Chul-Hwan Lee
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - James Stafford
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Ali Shilatifard
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Danny Reinberg
- Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
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Abstract
The fidelity of DNA replication is determined by many factors, here simplified as the contribution of the DNA polymerase (nucleotide selectivity and proofreading), mismatch repair, a balanced supply of nucleotides, and the condition of the DNA template (both in terms of sequence context and the presence of DNA lesions). This review discusses the contribution and interplay between these factors to the overall fidelity of DNA replication.
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Affiliation(s)
- Rais A Ganai
- Department of Medical Biochemistry and Biophysics, Umeå University, SE 901 87 Umeå, Sweden; Howard Hughes Medical Institute, Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, NY 10016, USA
| | - Erik Johansson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE 901 87 Umeå, Sweden.
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Ganai RA, Zhang XP, Heyer WD, Johansson E. Strand displacement synthesis by yeast DNA polymerase ε. Nucleic Acids Res 2016; 44:8229-40. [PMID: 27325747 PMCID: PMC5041465 DOI: 10.1093/nar/gkw556] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/09/2016] [Indexed: 11/30/2022] Open
Abstract
DNA polymerase ε (Pol ε) is a replicative DNA polymerase with an associated 3′–5′ exonuclease activity. Here, we explored the capacity of Pol ε to perform strand displacement synthesis, a process that influences many DNA transactions in vivo. We found that Pol ε is unable to carry out extended strand displacement synthesis unless its 3′–5′ exonuclease activity is removed. However, the wild-type Pol ε holoenzyme efficiently displaced one nucleotide when encountering double-stranded DNA after filling a gap or nicked DNA. A flap, mimicking a D-loop or a hairpin structure, on the 5′ end of the blocking primer inhibited Pol ε from synthesizing DNA up to the fork junction. This inhibition was observed for Pol ε but not with Pol δ, RB69 gp43 or Pol η. Neither was Pol ε able to extend a D-loop in reconstitution experiments. Finally, we show that the observed strand displacement synthesis by exonuclease-deficient Pol ε is distributive. Our results suggest that Pol ε is unable to extend the invading strand in D-loops during homologous recombination or to add more than two nucleotides during long-patch base excision repair. Our results support the hypothesis that Pol ε participates in short-patch base excision repair and ribonucleotide excision repair.
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Affiliation(s)
- Rais A Ganai
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden Howard Hughes Medical Institute, Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, NY 10016, USA
| | - Xiao-Ping Zhang
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616-8665, USA
| | - Wolf-Dietrich Heyer
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616-8665, USA
| | - Erik Johansson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
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Abstract
The balance between exonuclease and polymerase activities promotes DNA synthesis over degradation when nucleotides are correctly added to the new strand by replicative B-family polymerases. Misincorporations shift the balance toward the exonuclease site, and the balance tips back in favor of DNA synthesis when the incorrect nucleotides have been removed. Most B-family DNA polymerases have an extended β-hairpin loop that appears to be important for switching from the exonuclease site to the polymerase site, a process that affects fidelity of the DNA polymerase. Here, we show that DNA polymerase ε can switch between the polymerase site and exonuclease site in a processive manner despite the absence of an extended β-hairpin loop. K967 and R988 are two conserved amino acids in the palm and thumb domain that interact with bases on the primer strand in the minor groove at positions n−2 and n−4/n−5, respectively. DNA polymerase ε depends on both K967 and R988 to stabilize the 3′-terminus of the DNA within the polymerase site and on R988 to processively switch between the exonuclease and polymerase sites. Based on a structural alignment with DNA polymerase δ, we propose that arginines corresponding to R988 might have a similar function in other B-family polymerases.
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Affiliation(s)
- Rais A Ganai
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Göran O Bylund
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Erik Johansson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
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Abstract
The holoenzyme of yeast DNA polymerase ϵ (Pol ϵ) consists of four subunits: Pol2, Dpb2, Dpb3, and Dpb4. A protease-sensitive site results in an N-terminal proteolytic fragment of Pol2, called Pol2core, that consists of the catalytic core of Pol ϵ and retains both polymerase and exonuclease activities. Pre-steady-state kinetics showed that the exonuclease rates on single-stranded, double-stranded, and mismatched DNA were comparable between Pol ϵ and Pol2core. Single-turnover pre-steady-state kinetics also showed that the kpol of Pol ϵ and Pol2core were comparable when preloading the polymerase onto the primer-template before adding Mg(2+) and dTTP. However, a global fit of the data over six sequential nucleotide incorporations revealed that the overall polymerization rate and processivity were higher for Pol ϵ than for Pol2core. The largest difference between Pol ϵ and Pol2core was observed when challenged for the formation of a ternary complex and incorporation of the first nucleotide. Pol ϵ needed less than 1 s to incorporate a nucleotide, but several seconds passed before Pol2core incorporated detectable levels of the first nucleotide. We conclude that the accessory subunits and the C terminus of Pol2 do not influence the catalytic rate of Pol ϵ but facilitate the loading and incorporation of the first nucleotide by Pol ϵ.
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Affiliation(s)
- Rais A Ganai
- From the Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Pia Osterman
- From the Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Erik Johansson
- From the Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
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