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Mollapour Sisakht M, Amirkhani MA, Nilforoushzadeh MA. SWI/SNF complex, promising target in melanoma therapy: Snapshot view. Front Med (Lausanne) 2023; 10:1096615. [PMID: 36844227 PMCID: PMC9947295 DOI: 10.3389/fmed.2023.1096615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 01/20/2023] [Indexed: 02/11/2023] Open
Abstract
Therapeutic strategies based on epigenetic regulators are rapidly increasing in light of recent advances in discovering the role of epigenetic factors in response and sensitivity to therapy. Although loss-of-function mutations in genes encoding the SWItch/Sucrose NonFermentable (SWI/SNF) subunits play an important role in the occurrence of ~34% of melanomas, the potential of using inhibitors and synthetic lethality interactions between key subunits of the complex that play an important role in melanoma progression must be considered. Here, we discuss the importance of the clinical application of SWI/SNF subunits as a promising potential therapeutic in melanoma.
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Affiliation(s)
- Mahsa Mollapour Sisakht
- Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran,Department of Biochemistry, Erasmus University Medical Center, Rotterdam, Netherlands,*Correspondence: Mahsa Mollapour Sisakht ✉ ; ✉
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2
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Nguyen VT, Tessema M, Weissman BE. The SWI/SNF Complex: A Frequently Mutated Chromatin Remodeling Complex in Cancer. Cancer Treat Res 2023; 190:211-244. [PMID: 38113003 DOI: 10.1007/978-3-031-45654-1_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
The switch/sucrose non-fermenting (SWI/SNF) chromatin remodeling complex is a global regulator of gene expression known to maintain nucleosome-depleted regions at active enhancers and promoters. The mammalian SWI/SNF protein subunits are encoded by 29 genes and 11-15 subunits including an ATPase domain of either SMARCA4 (BRG1) or SMARCA2 (BRM) are assembled into a complex. Based on the distinct subunits, SWI/SNF are grouped into 3 major types (subfamilies): the canonical BRG1/BRM-associated factor (BAF/cBAF), polybromo-associated BAF (PBAF), and non-canonical BAF (GBAF/ncBAF). Pan-cancer genome sequencing studies have shown that nearly 25% of all cancers bear mutations in subunits of the SWI/SNF complex, many of which are loss of function (LOF) mutations, suggesting a tumor suppressor role. Inactivation of SWI/SNF complex subunits causes widespread epigenetic dysfunction, including increased dependence on antagonistic components such as polycomb repressor complexes (PRC1/2) and altered enhancer regulation, likely promoting an oncogenic state leading to cancer. Despite the prevalence of mutations, most SWI/SNF-mutant cancers lack targeted therapeutic strategies. Defining the dependencies created by LOF mutations in SWI/SNF subunits will identify better targets for these cancers.
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Affiliation(s)
- Vinh The Nguyen
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
- Curriculum in Toxicology and Environmental Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
| | - Mathewos Tessema
- Lung Cancer Program, Lovelace Biomedical Research Institute, Albuquerque, NM, USA
| | - Bernard Ellis Weissman
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
- Curriculum in Toxicology and Environmental Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
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Dreier MR, de la Serna IL. SWI/SNF Chromatin Remodeling Enzymes in Melanoma. EPIGENOMES 2022; 6:epigenomes6010010. [PMID: 35323214 PMCID: PMC8947417 DOI: 10.3390/epigenomes6010010] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/07/2022] [Accepted: 03/14/2022] [Indexed: 11/16/2022] Open
Abstract
Melanoma is an aggressive malignancy that arises from the transformation of melanocytes on the skin, mucosal membranes, and uvea of the eye. SWI/SNF chromatin remodeling enzymes are multi-subunit complexes that play important roles in the development of the melanocyte lineage and in the response to ultraviolet radiation, a key environmental risk factor for developing cutaneous melanoma. Exome sequencing has revealed frequent loss of function mutations in genes encoding SWI/SNF subunits in melanoma. However, some SWI/SNF subunits have also been demonstrated to have pro-tumorigenic roles in melanoma and to affect sensitivity to therapeutics. This review summarizes studies that have implicated SWI/SNF components in melanomagenesis and have evaluated how SWI/SNF subunits modulate the response to current therapeutics.
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Bohm KA, Hodges AJ, Czaja W, Selvam K, Smerdon MJ, Mao P, Wyrick JJ. Distinct roles for RSC and SWI/SNF chromatin remodelers in genomic excision repair. Genome Res 2021; 31:1047-1059. [PMID: 34001524 PMCID: PMC8168587 DOI: 10.1101/gr.274373.120] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 04/19/2021] [Indexed: 12/30/2022]
Abstract
Nucleosomes are a significant barrier to the repair of UV damage because they impede damage recognition by nucleotide excision repair (NER). The RSC and SWI/SNF chromatin remodelers function in cells to promote DNA access by moving or evicting nucleosomes, and both have been linked to NER in yeast. Here, we report genome-wide repair maps of UV-induced cyclobutane pyrimidine dimers (CPDs) in yeast cells lacking RSC or SWI/SNF activity. Our data indicate that SWI/SNF is not generally required for NER but instead promotes repair of CPD lesions at specific yeast genes. In contrast, mutation or depletion of RSC subunits causes a general defect in NER across the yeast genome. Our data indicate that RSC is required for repair not only in nucleosomal DNA but also in neighboring linker DNA and nucleosome-free regions (NFRs). Although depletion of the RSC catalytic subunit also affects base excision repair (BER) of N-methylpurine (NMP) lesions, RSC activity is less important for BER in linker DNA and NFRs. Furthermore, our data indicate that RSC plays a direct role in transcription-coupled NER (TC-NER) of transcribed DNA. These findings help to define the specific genomic and chromatin contexts in which each chromatin remodeler functions in DNA repair, and indicate that RSC plays a unique function in facilitating repair by both NER subpathways.
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Affiliation(s)
- Kaitlynne A Bohm
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - Amelia J Hodges
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - Wioletta Czaja
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - Kathiresan Selvam
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - Michael J Smerdon
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - Peng Mao
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - John J Wyrick
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA.,Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
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Kashyap MP, Sinha R, Mukhtar MS, Athar M. Epigenetic regulation in the pathogenesis of non-melanoma skin cancer. Semin Cancer Biol 2020; 83:36-56. [PMID: 33242578 DOI: 10.1016/j.semcancer.2020.11.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 02/07/2023]
Abstract
Understanding of cancer with the help of ever-expanding cutting edge technological tools and bioinformatics is revolutionizing modern cancer research by broadening the space of discovery window of various genomic and epigenomic processes. Genomics data integrated with multi-omics layering have advanced cancer research. Uncovering such layers of genetic mutations/modifications, epigenetic regulation and their role in the complex pathophysiology of cancer progression could lead to novel therapeutic interventions. Although a plethora of literature is available in public domain defining the role of various tumor driver gene mutations, understanding of epigenetic regulation of cancer is still emerging. This review focuses on epigenetic regulation association with the pathogenesis of non-melanoma skin cancer (NMSC). NMSC has higher prevalence in Caucasian populations compared to other races. Due to lack of proper reporting to cancer registries, the incidence rates for NMSC worldwide cannot be accurately estimated. However, this is the most common neoplasm in humans, and millions of new cases per year are reported in the United States alone. In organ transplant recipients, the incidence of NMSC particularly of squamous cell carcinoma (SCC) is very high and these SCCs frequently become metastatic and lethal. Understanding of solar ultraviolet (UV) light-induced damage and impaired DNA repair process leading to DNA mutations and nuclear instability provide an insight into the pathogenesis of metastatic neoplasm. This review discusses the recent advances in the field of epigenetics of NMSCs. Particularly, the role of DNA methylation, histone hyperacetylation and non-coding RNA such as long-chain noncoding (lnc) RNAs, circular RNAs and miRNA in the disease progression are summarized.
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Affiliation(s)
- Mahendra Pratap Kashyap
- UAB Research Center of Excellence in Arsenicals, Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Rajesh Sinha
- UAB Research Center of Excellence in Arsenicals, Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - M Shahid Mukhtar
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mohammad Athar
- UAB Research Center of Excellence in Arsenicals, Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Jancewicz I, Siedlecki JA, Sarnowski TJ, Sarnowska E. BRM: the core ATPase subunit of SWI/SNF chromatin-remodelling complex-a tumour suppressor or tumour-promoting factor? Epigenetics Chromatin 2019; 12:68. [PMID: 31722744 PMCID: PMC6852734 DOI: 10.1186/s13072-019-0315-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 10/31/2019] [Indexed: 02/07/2023] Open
Abstract
BRM (BRAHMA) is a core, SWI2/SNF2-type ATPase subunit of SWI/SNF chromatin-remodelling complex (CRC) involved in various important regulatory processes including development. Mutations in SMARCA2, a BRM-encoding gene as well as overexpression or epigenetic silencing were found in various human diseases including cancer. Missense mutations in SMARCA2 gene were recently connected with occurrence of Nicolaides-Baraitser genetics syndrome. By contrast, SMARCA2 duplication rather than mutations is characteristic for Coffin-Siris syndrome. It is believed that BRM usually acts as a tumour suppressor or a tumour susceptibility gene. However, other studies provided evidence that BRM function may differ depending on the cancer type and the disease stage, where BRM may play a role in the disease progression. The existence of alternative splicing forms of SMARCA2 gene, leading to appearance of truncated functional, loss of function or gain-of-function forms of BRM protein suggest a far more complicated mode of BRM-containing SWI/SNF CRCs actions. Therefore, the summary of recent knowledge regarding BRM alteration in various types of cancer and highlighting of differences and commonalities between BRM and BRG1, another SWI2/SNF2 type ATPase, will lead to better understanding of SWI/SNF CRCs function in cancer development/progression. BRM has been recently proposed as an attractive target for various anticancer therapies including the use of small molecule inhibitors, synthetic lethality induction or proteolysis-targeting chimera (PROTAC). However, such attempts have some limitations and may lead to severe side effects given the homology of BRM ATPase domain to other ATPases, as well as due to the tissue-specific appearance of BRM- and BRG1-containing SWI/SNF CRC classes. Thus, a better insight into BRM-containing SWI/SNF CRCs function in human tissues and cancers is clearly required to provide a solid basis for establishment of new safe anticancer therapies.
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Affiliation(s)
- Iga Jancewicz
- Department of Molecular and Translational Oncology, The Maria Sklodowska-Curie Institute-Oncology Center in Warsaw, Wawelska 15B, 02-034, Warsaw, Poland
| | - Janusz A Siedlecki
- Department of Molecular and Translational Oncology, The Maria Sklodowska-Curie Institute-Oncology Center in Warsaw, Wawelska 15B, 02-034, Warsaw, Poland
| | - Tomasz J Sarnowski
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland.
| | - Elzbieta Sarnowska
- Department of Molecular and Translational Oncology, The Maria Sklodowska-Curie Institute-Oncology Center in Warsaw, Wawelska 15B, 02-034, Warsaw, Poland.
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Orlando KA, Nguyen V, Raab JR, Walhart T, Weissman BE. Remodeling the cancer epigenome: mutations in the SWI/SNF complex offer new therapeutic opportunities. Expert Rev Anticancer Ther 2019; 19:375-391. [PMID: 30986130 DOI: 10.1080/14737140.2019.1605905] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Cancer genome sequencing studies have discovered mutations in members of the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin-remodeling complex in nearly 25% of human cancers. The SWI/SNF complex, first discovered in S. cerevisiae, shows strong conservation from yeast to Drosophila to mammals, contains approximately 10-12 subunits and regulates nucleosome positioning through the energy generated by its ATPase subunits. The unexpected finding of frequent mutations in the complex has fueled studies to identify the mechanisms that drive tumor development and the accompanying therapeutic vulnerabilities. Areas covered: In the review, we focus upon the potential roles different SWI/SNF subunit mutations play in human oncogenesis, their common and unique mechanisms of transformation and the potential for translating these mechanisms into targeted therapies for SWI/SNF-mutant tumors. Expert opinion: We currently have limited insights into how mutations in different SWI/SNF subunits drive the development of human tumors. Because the SWI/SNF complex participates in a broad range of normal cellular functions, defining specific oncogenic pathways has proved difficult. In addition, therapeutic options for SWI/SNF-mutant cancers have mainly evolved from high-throughput screens of cell lines with mutations in different subunits. Future studies should follow a more coherent plan to pinpoint common vulnerabilities among these tumors.
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Affiliation(s)
- Krystal A Orlando
- a Department of Pathology and Laboratory Medicine , University of North Carolina , Chapel Hill , NC , USA
| | - Vinh Nguyen
- b Curriculum in Toxicology and Environmental Medicine , University of North Carolina , Chapel Hill , NC , USA
| | - Jesse R Raab
- c Department of Genetics , University of North Carolina , Chapel Hill , NC , USA
| | - Tara Walhart
- d Lineberger Comprehensive Cancer Center , University of North Carolina , Chapel Hill , NC , USA
| | - Bernard E Weissman
- a Department of Pathology and Laboratory Medicine , University of North Carolina , Chapel Hill , NC , USA.,b Curriculum in Toxicology and Environmental Medicine , University of North Carolina , Chapel Hill , NC , USA.,d Lineberger Comprehensive Cancer Center , University of North Carolina , Chapel Hill , NC , USA
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8
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Farrell AW, Halliday GM, Lyons JG. Brahma deficiency in keratinocytes promotes UV carcinogenesis by accelerating the escape from cell cycle arrest and the formation of DNA photolesions. J Dermatol Sci 2018; 92:254-263. [PMID: 30522882 DOI: 10.1016/j.jdermsci.2018.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/06/2018] [Accepted: 11/19/2018] [Indexed: 01/18/2023]
Abstract
BACKGROUND Ultraviolet radiation (UVR) is the principal cause of keratinocyte skin cancers. Previous work found that levels of the chromatin remodelling protein, Brahma (Brm), are diminished during the progression from actinic keratoses to cutaneous squamous cell carcinomas in humans, and its loss in UV-irradiated mouse skin causes epidermal hyperplasia and increased tumour incidence. METHODS The skins of mice and mouse and human keratinocytes deficient in Brm were exposed to UVR and evaluated for cell cycle progression and DNA damage response. OBJECTIVE To identify the mechanisms by which loss of Brm contributes to UVR-induced skin carcinogenesis. RESULTS In both mouse keratinocytes and HaCaT cells, Brm deficiency led to an increased cell population growth following UVR exposure compared to cells with normal levels of Brm. Cell cycle analysis using a novel assay showed that Brm-deficient keratinocytes entered cell cycle arrest normally, but escaped from cell cycle arrest faster, enabling them to begin proliferating earlier. In mouse keratinocytes, Brm primarily affected accumulation in G0/G1-phase, whereas in HaCaT cells, which lack normal p53, accumulation in G2/M-phase was affected. Brm-deficient keratinocytes in mouse skin and human cell cultures also had higher levels of UVR-induced cyclobutane pyrimidine dimer photolesions. These effects occurred without any compensatory increase in DNA repair or cell death to remove photolesions or the cells that harbor them from the keratinocyte population. CONCLUSION The loss of Brm in keratinocytes exposed to UVR enables them to resume proliferation while harboring DNA photolesions, leading to an increased fixation of mutations and, consequently, increased carcinogenesis.
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Affiliation(s)
- Andrew W Farrell
- Dermatology, Central Clinical School, and Bosch Institute, University of Sydney, Sydney, NSW, Australia
| | - Gary M Halliday
- Dermatology, Central Clinical School, and Bosch Institute, University of Sydney, Sydney, NSW, Australia
| | - J Guy Lyons
- Dermatology, Central Clinical School, and Bosch Institute, University of Sydney, Sydney, NSW, Australia; Centenary Institute, Cancer Services, Royal Prince Alfred Hospital, Dermatology, Bosch Institute, University of Sydney, Camperdown, NSW 2050, Australia.
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9
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Delic NC, Lyons JG, Di Girolamo N, Halliday GM. Damaging Effects of Ultraviolet Radiation on the Cornea. Photochem Photobiol 2017; 93:920-929. [PMID: 27935054 DOI: 10.1111/php.12686] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 10/18/2016] [Indexed: 01/22/2023]
Abstract
The cornea sits at the anterior aspect of the eye and, like the skin, is highly exposed to ultraviolet radiation (UVR). The cornea blocks a significant proportion of UVB from reaching the posterior structures of the eye. However, UVA can penetrate the full thickness of the cornea, even reaching the anterior portion of the lens. Epidemiological data indicate that UVR is a contributing factor for a multitude of diseases of the cornea including pterygium, photokeratitis, climatic droplet keratopathy and ocular surface squamous neoplasia (OSSN), although the pathogenic mechanisms of each require further elucidation. UVR is a well-known genotoxic agent, and its effects have been well characterized in organs such as the skin. However, we are only beginning to identify its effects on the cornea, such as the UVR signature C → T and CC → TT transversions identified by sequencing and increased proliferative and shedding rates in response to UVR exposure. Alarmingly, a single low-dose exposure of UVR to the cornea is sufficient to elicit genetic, molecular and cellular changes, supporting the consideration of using protective measures, such as wearing sunglasses when outdoors. The aim of this review was to describe the adverse effects of UVR on the cornea.
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Affiliation(s)
- Naomi C Delic
- Discipline of Dermatology, Bosch Institute, University of Sydney, Camperdown, NSW, Australia.,Immune Imaging Program, Centenary Institute for Cancer Medicine and Cell Biology, Camperdown, NSW, Australia
| | - J Guy Lyons
- Discipline of Dermatology, Bosch Institute, University of Sydney, Camperdown, NSW, Australia.,Immune Imaging Program, Centenary Institute for Cancer Medicine and Cell Biology, Camperdown, NSW, Australia.,Sydney Head and Neck Cancer Institute, Cancer Services, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Nick Di Girolamo
- Department of Pathology, School of Medical Sciences, University of New South Wales, Randwick, NSW, Australia
| | - Gary M Halliday
- Discipline of Dermatology, Bosch Institute, University of Sydney, Camperdown, NSW, Australia
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10
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An Optimization-Driven Analysis Pipeline to Uncover Biomarkers and Signaling Paths: Cervix Cancer. MICROARRAYS 2015; 4:287-310. [PMID: 26388997 PMCID: PMC4573573 DOI: 10.3390/microarrays4020287] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Establishing how a series of potentially important genes might relate to each other is relevant to understand the origin and evolution of illnesses, such as cancer. High-throughput biological experiments have played a critical role in providing information in this regard. A special challenge, however, is that of trying to conciliate information from separate microarray experiments to build a potential genetic signaling path. This work proposes a two-step analysis pipeline, based on optimization, to approach meta-analysis aiming to build a proxy for a genetic signaling path.
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11
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Mehrotra A, Mehta G, Aras S, Trivedi A, de la Serna IL. SWI/SNF chromatin remodeling enzymes in melanocyte differentiation and melanoma. Crit Rev Eukaryot Gene Expr 2015; 24:151-61. [PMID: 24940768 DOI: 10.1615/critreveukaryotgeneexpr.2014007882] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Epidermal melanocytes are pigment-producing cells derived from the neural crest that protects skin from the damaging effects of solar radiation. Malignant melanoma, a highly aggressive cancer, arises from melanocytes. SWI/SNF enzymes are multiprotein complexes that remodel chromatin structure and have extensive roles in cellular differentiation. Components of the complex have been found to be mutated or lost in several human cancers. This review focuses on studies that implicate SWI/SNF enzymes in melanocyte differentiation and in melanoma.
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Affiliation(s)
- A Mehrotra
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH
| | - G Mehta
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH
| | - S Aras
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH
| | - A Trivedi
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH
| | - I L de la Serna
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, OH
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Hassan NMM, Painter N, Howlett CR, Farrell AW, Di Girolamo N, Lyons JG, Halliday GM. Brm inhibits the proliferative response of keratinocytes and corneal epithelial cells to ultraviolet radiation-induced damage. PLoS One 2014; 9:e107931. [PMID: 25254962 PMCID: PMC4177874 DOI: 10.1371/journal.pone.0107931] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 08/17/2014] [Indexed: 11/18/2022] Open
Abstract
Ultraviolet radiation (UV) from sunlight is the primary cause of skin and ocular neoplasia. Brahma (BRM) is part of the SWI/SNF chromatin remodeling complex. It provides energy for rearrangement of chromatin structure. Previously we have found that human skin tumours have a hotspot mutation in BRM and that protein levels are substantially reduced. Brm−/− mice have enhanced susceptibility to photocarcinogenesis. In these experiments, Brm−/− mice, with both or a single Trp53 allele were exposed to UV for 2 or 25 weeks. In wild type mice the central cornea and stroma became atrophic with increasing time of exposure while the peripheral regions became hyperplastic, presumably as a reparative process. Brm−/−, Trp53+/−, and particularly the Brm−/− Trp53+/− mice had an exaggerated hyperplastic regeneration response in the corneal epithelium and stroma so that the central epithelial atrophy or stromal loss was reduced. UV induced hyperplasia of the epidermis and corneal epithelium, with an increase in the number of dividing cells as determined by Ki-67 expression. This response was considerably greater in both the Brm−/− Trp53+/+ and Brm−/− Trp53+/− mice indicating that Brm protects from UV-induced enhancement of cell division, even with loss of one Trp53 allele. Cell division was disorganized in Brm−/− mice. Rather than being restricted to the basement membrane region, dividing cells were also present in the suprabasal regions of both tissues. Brm appears to be a tumour suppressor gene that protects from skin and ocular photocarcinogenesis. These studies indicate that Brm protects from UV-induced hyperplastic growth in both cutaneous and corneal keratinocytes, which may contribute to the ability of Brm to protect from photocarcinogenesis.
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Affiliation(s)
- Nur Mohammad Monsur Hassan
- Discipline of Dermatology, Bosch Institute, Sydney Medical School, Royal Prince Alfred Hospital and University of Sydney, Sydney, Australia
| | - Nicole Painter
- Discipline of Dermatology, Bosch Institute, Sydney Medical School, Royal Prince Alfred Hospital and University of Sydney, Sydney, Australia
| | - C. Rolfe Howlett
- Department of Pathology and Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Andrew W. Farrell
- Discipline of Dermatology, Bosch Institute, Sydney Medical School, Royal Prince Alfred Hospital and University of Sydney, Sydney, Australia
| | - Nick Di Girolamo
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - J. Guy Lyons
- Discipline of Dermatology, Bosch Institute, Sydney Medical School, Royal Prince Alfred Hospital and University of Sydney, Sydney, Australia
- Sydney Head and Neck Cancer Institute, Cancer Services, Royal Prince Alfred Hospital, Sydney, Australia
| | - Gary M. Halliday
- Discipline of Dermatology, Bosch Institute, Sydney Medical School, Royal Prince Alfred Hospital and University of Sydney, Sydney, Australia
- * E-mail:
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13
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Helming KC, Wang X, Roberts CWM. Vulnerabilities of mutant SWI/SNF complexes in cancer. Cancer Cell 2014; 26:309-317. [PMID: 25203320 PMCID: PMC4159614 DOI: 10.1016/j.ccr.2014.07.018] [Citation(s) in RCA: 209] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/12/2014] [Accepted: 07/23/2014] [Indexed: 01/30/2023]
Abstract
Cancer genome sequencing efforts have revealed the novel theme that chromatin modifiers are frequently mutated across a wide spectrum of cancers. Mutations in genes encoding subunits of SWI/SNF (BAF) chromatin remodeling complexes are particularly prevalent, occurring in 20% of all human cancers. As these are typically loss-of-function mutations and not directly therapeutically targetable, central goals have been to elucidate mechanism and identify vulnerabilities created by these mutations. Here, we discuss emerging data that these mutations lead to the formation of aberrant residual SWI/SNF complexes that constitute a specific vulnerability and discuss the potential for exploiting these dependencies in SWI/SNF mutant cancers.
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Affiliation(s)
- Katherine C Helming
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02215, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Biological and Biomedical Sciences Program, Harvard Medical School, Boston, MA 02115, USA
| | - Xiaofeng Wang
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02215, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Charles W M Roberts
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02215, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
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14
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Biegel JA, Busse TM, Weissman BE. SWI/SNF chromatin remodeling complexes and cancer. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2014; 166C:350-66. [PMID: 25169151 DOI: 10.1002/ajmg.c.31410] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The identification of mutations and deletions in the SMARCB1 locus in chromosome band 22q11.2 in pediatric rhabdoid tumors provided the first evidence for the involvement of the SWI/SNF chromatin remodeling complex in cancer. Over the last 15 years, alterations in more than 20 members of the complex have been reported in a variety of human tumors. These include germline mutations and copy number alterations in SMARCB1, SMARCA4, SMARCE1, and PBRM1 that predispose carriers to both benign and malignant neoplasms. Somatic mutations, structural abnormalities, or epigenetic modifications that lead to reduced or aberrant expression of complex members have now been reported in more than 20% of malignancies, including both solid tumors and hematologic disorders in both children and adults. In this review, we will highlight the role of SMARCB1 in cancer as a paradigm for other tumors with alterations in SWI/SNF complex members and demonstrate the broad spectrum of mutations observed in complex members in different tumor types.
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Mehrotra A, Saladi SV, Trivedi AR, Aras S, Qi H, Jayanthy A, Setaluri V, de la Serna IL. Modulation of Brahma expression by the mitogen-activated protein kinase/extracellular signal regulated kinase pathway is associated with changes in melanoma proliferation. Arch Biochem Biophys 2014; 563:125-35. [PMID: 25026375 DOI: 10.1016/j.abb.2014.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 07/03/2014] [Accepted: 07/06/2014] [Indexed: 10/25/2022]
Abstract
Brahma (BRM) and Brahma-related gene 1(BRG1) are catalytic subunits of SWItch/sucrose non-fermentable (SWI/SNF) chromatin remodeling complexes. BRM is epigenetically silenced in a wide-range of tumors. Mutations in the v-raf murine sarcoma viral oncogene homolog B1 (BRAF) gene occur frequently in melanoma and lead to constitutive activation of the mitogen-activated protein kinase (MAPK)/extracellular signal regulated kinase (ERK1/2) pathway. We tested the hypothesis that BRM expression is modulated by oncogenic BRAF and phosphorylation of ERK1/2 in melanocytes and melanoma cells. Expression of oncogenic BRAF in melanocytes and melanoma cells that are wild-type for BRAF decreased BRM expression and increased BRG1 expression. Inhibition of mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) or selective inhibition of BRAF in melanoma cells that harbor oncogenic BRAF increased BRM expression and decreased BRG1 expression. Increased BRM expression was associated with increased histone acetylation on the BRM promoter. Over-expression of BRM in melanoma cells that harbor oncogenic BRAF promoted changes in cell cycle progression and apoptosis consistent with a tumor suppressive role. Upon inhibition of BRAF(V600E) with PLX4032, BRM promoted survival. PLX4032 induced changes in BRM function were correlated with increased acetylation of the BRM protein. This study provides insights into the epigenetic consequences of inhibiting oncogenic BRAF in melanoma through modulation of SWI/SNF subunit expression and function.
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Affiliation(s)
- Aanchal Mehrotra
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States
| | - Srinivas Vinod Saladi
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States
| | - Archit R Trivedi
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States
| | - Shweta Aras
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States
| | - Huiling Qi
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States
| | - Ashika Jayanthy
- University of Wisconsin, Department of Dermatology, 1300 University Avenue, #439, Madison, WI 53706, United States
| | - Vijayasaradhi Setaluri
- University of Wisconsin, Department of Dermatology, 1300 University Avenue, #439, Madison, WI 53706, United States
| | - Ivana L de la Serna
- University of Toledo College of Medicine, Department of Biochemistry and Cancer Biology, 3035 Arlington Ave, Toledo, OH 43614, United States.
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Perdigoto CN, Valdes VJ, Bardot ES, Ezhkova E. Epigenetic regulation of epidermal differentiation. Cold Spring Harb Perspect Med 2014; 4:4/2/a015263. [PMID: 24492849 DOI: 10.1101/cshperspect.a015263] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In a cell, the chromatin state is controlled by the highly regulated interplay of epigenetic mechanisms ranging from DNA methylation and incorporation of different histone variants to posttranslational modification of histones and ATP-dependent chromatin remodeling. These changes alter the structure of the chromatin to either facilitate or restrict the access of transcription machinery to DNA. These epigenetic modifications function to exquisitely orchestrate the expression of different genes, and together constitute the epigenome of a cell. In the skin, different epigenetic regulators form a regulatory network that operates to guarantee skin stem cell maintenance while controlling differentiation to multiple skin structures. In this review, we will discuss recent findings on epigenetic mechanisms of skin control and their relationship to skin pathologies.
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Affiliation(s)
- Carolina N Perdigoto
- Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
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Sánchez-Peña ML, Isaza CE, Pérez-Morales J, Rodríguez-Padilla C, Castro JM, Cabrera-Ríos M. Identification of potential biomarkers from microarray experiments using multiple criteria optimization. Cancer Med 2013; 2:253-65. [PMID: 23634293 PMCID: PMC3639664 DOI: 10.1002/cam4.69] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 01/23/2013] [Accepted: 01/24/2013] [Indexed: 12/14/2022] Open
Abstract
Microarray experiments are capable of determining the relative expression of tens of thousands of genes simultaneously, thus resulting in very large databases. The analysis of these databases and the extraction of biologically relevant knowledge from them are challenging tasks. The identification of potential cancer biomarker genes is one of the most important aims for microarray analysis and, as such, has been widely targeted in the literature. However, identifying a set of these genes consistently across different experiments, researches, microarray platforms, or cancer types is still an elusive endeavor. Besides the inherent difficulty of the large and nonconstant variability in these experiments and the incommensurability between different microarray technologies, there is the issue of the users having to adjust a series of parameters that significantly affect the outcome of the analyses and that do not have a biological or medical meaning. In this study, the identification of potential cancer biomarkers from microarray data is casted as a multiple criteria optimization (MCO) problem. The efficient solutions to this problem, found here through data envelopment analysis (DEA), are associated to genes that are proposed as potential cancer biomarkers. The method does not require any parameter adjustment by the user, and thus fosters repeatability. The approach also allows the analysis of different microarray experiments, microarray platforms, and cancer types simultaneously. The results include the analysis of three publicly available microarray databases related to cervix cancer. This study points to the feasibility of modeling the selection of potential cancer biomarkers from microarray data as an MCO problem and solve it using DEA. Using MCO entails a new optic to the identification of potential cancer biomarkers as it does not require the definition of a threshold value to establish significance for a particular gene and the selection of a normalization procedure to compare different experiments is no longer necessary.
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Affiliation(s)
- Matilde L Sánchez-Peña
- Bio IE Lab, Industrial Engineering Department, University of Puerto Rico at Mayaguez, Mayagüez, Puerto Rico
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Berman B, Cockerell CJ. Pathobiology of actinic keratosis: ultraviolet-dependent keratinocyte proliferation. J Am Acad Dermatol 2013; 68:S10-9. [PMID: 23228301 DOI: 10.1016/j.jaad.2012.09.053] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 09/04/2012] [Indexed: 02/04/2023]
Abstract
Actinic keratoses are proliferations of transformed neoplastic keratinocytes in the epidermis that are the result of cumulative ultraviolet (UV) radiation from sun exposure. They are commonly found on sites of sun-exposed skin such as the face, balding scalp, and back of the hand. Although UV exposure does exert certain beneficial effects on the skin, excessive exposure to UV radiation induces multiple cascades of molecular signaling events at the cellular level that produce inflammation, immunosuppression, failure of apoptosis, and aberrant differentiation. Cumulatively, these actions result in mutagenesis and, ultimately, carcinogenesis. This article provides a brief overview of the key mediators that are implicated in the pathobiology of actinic keratosis. Three evolutionary possibilities exist for these keratoses in the absence of treatment: (1) spontaneous remission, which can be common; (2) remaining stable, without further progression; or (3) transformation to invasive squamous cell carcinoma, which may metastasize. Because the effects of UV radiation on the skin are complex, it is not yet fully clear how all of the mediators of actinic keratosis progression are interrelated. Nonetheless, some represent potential therapeutic targets, because it is clear that directing therapy to the effects of UV radiation at a number of different levels could interrupt and possibly reverse the mechanisms leading to malignant transformation.
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Affiliation(s)
- Brian Berman
- Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA
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Gonzalez-Perez A, Jene-Sanz A, Lopez-Bigas N. The mutational landscape of chromatin regulatory factors across 4,623 tumor samples. Genome Biol 2013; 14:r106. [PMID: 24063517 PMCID: PMC4054018 DOI: 10.1186/gb-2013-14-9-r106] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 09/24/2013] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Chromatin regulatory factors are emerging as important genes in cancer development and are regarded as interesting candidates for novel targets for cancer treatment. However, we lack a comprehensive understanding of the role of this group of genes in different cancer types. RESULTS We have analyzed 4,623 tumor samples from thirteen anatomical sites to determine which chromatin regulatory factors are candidate drivers in these different sites. We identify 34 chromatin regulatory factors that are likely drivers in tumors from at least one site, all with relatively low mutational frequency. We also analyze the relative importance of mutations in this group of genes for the development of tumorigenesis in each site, and indifferent tumor types from the same site. CONCLUSIONS We find that, although tumors from all thirteen sites show mutations in likely driver chromatin regulatory factors, these are more prevalent in tumors arising from certain tissues. With the exception of hematopoietic, liver and kidney tumors, as a median, the mutated factors are less than one fifth of all mutated drivers across all sites analyzed. We also show that mutations in two of these genes, MLL and EP300, correlate with broad expression changes across cancer cell lines, thus presenting at least one mechanism through which these mutations could contribute to tumorigenesis in cells of the corresponding tissues.
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Affiliation(s)
- Abel Gonzalez-Perez
- Research Unit on Biomedical Informatics, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Dr. Aiguader 88, Barcelona, Spain
| | - Alba Jene-Sanz
- Research Unit on Biomedical Informatics, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Dr. Aiguader 88, Barcelona, Spain
| | - Nuria Lopez-Bigas
- Research Unit on Biomedical Informatics, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Dr. Aiguader 88, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
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Andreu-Vieyra CV, Liang G. Nucleosome occupancy and gene regulation during tumorigenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 754:109-34. [PMID: 22956498 DOI: 10.1007/978-1-4419-9967-2_5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nucleosomes are the basic structural units of eukaryotic chromatin. In recent years, it has become evident that nucleosomes and their position, in concert with other epigenetic mechanisms (such as DNA methylation, histone modifications, changes in histone variants, as well as small noncoding regulatory RNAs) play essential roles in the control of gene expression. Here, we discuss the mechanisms and factors that regulate nucleosome position and gene expression in normal and cancer cells.
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Halliday GM, Zhou Y, Sou PW, Huang XXJ, Rana S, Bugeja MJ, Painter N, Scolyer RA, Muchardt C, Di Girolamo N, Lyons JG. The absence of Brm exacerbates photocarcinogenesis. Exp Dermatol 2012; 21:599-604. [PMID: 22775994 DOI: 10.1111/j.1600-0625.2012.01522.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Brm is an ATPase subunit of the SWI/SNF chromatin-remodelling complex. Previously, we identified a novel hotspot mutation in Brm in human skin cancer, which is caused by exposure to ultraviolet radiation (UVR). As SWI/SNF is involved in DNA repair, we investigated whether Brm-/- mice had enhanced photocarcinogenesis. P53+/- and Brm-/-p53+/- mice were also examined as the p53 tumor suppressor gene is mutated early during human skin carcinogenesis. Mice were exposed to a low-dose irradiation protocol that caused few skin tumors in wild-type mice. Brm-/- mice with both p53 alleles intact had an increased incidence of skin and ocular tumors compared to Brm+/+p53+/+ controls. Brm loss in p53+/- mice did not further enhance skin or ocular cancer incidence beyond the increased photocarcinogenesis in p53+/- mice. However, the skin tumors that arose early in Brm-/- p53+/- mice had a higher growth rate. Brm-/- did not prevent UVR-induced apoptotic sunburn cell formation, which is a protective response. Unexpectedly, Brm-/- inhibited UVR-induced immunosuppression, which would be predicted to reduce rather than enhance photocarcinogenesis. In conclusion, the absence of Brm increased skin and ocular photocarcinogenesis. Even when one allele of p53 is lost, Brm has additional tumor suppressing capability.
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Affiliation(s)
- Gary M Halliday
- Discipline of Dermatology, Bosch Institute, Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
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Thompson LH. Recognition, signaling, and repair of DNA double-strand breaks produced by ionizing radiation in mammalian cells: the molecular choreography. Mutat Res 2012; 751:158-246. [PMID: 22743550 DOI: 10.1016/j.mrrev.2012.06.002] [Citation(s) in RCA: 261] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 06/09/2012] [Accepted: 06/16/2012] [Indexed: 12/15/2022]
Abstract
The faithful maintenance of chromosome continuity in human cells during DNA replication and repair is critical for preventing the conversion of normal diploid cells to an oncogenic state. The evolution of higher eukaryotic cells endowed them with a large genetic investment in the molecular machinery that ensures chromosome stability. In mammalian and other vertebrate cells, the elimination of double-strand breaks with minimal nucleotide sequence change involves the spatiotemporal orchestration of a seemingly endless number of proteins ranging in their action from the nucleotide level to nucleosome organization and chromosome architecture. DNA DSBs trigger a myriad of post-translational modifications that alter catalytic activities and the specificity of protein interactions: phosphorylation, acetylation, methylation, ubiquitylation, and SUMOylation, followed by the reversal of these changes as repair is completed. "Superfluous" protein recruitment to damage sites, functional redundancy, and alternative pathways ensure that DSB repair is extremely efficient, both quantitatively and qualitatively. This review strives to integrate the information about the molecular mechanisms of DSB repair that has emerged over the last two decades with a focus on DSBs produced by the prototype agent ionizing radiation (IR). The exponential growth of molecular studies, heavily driven by RNA knockdown technology, now reveals an outline of how many key protein players in genome stability and cancer biology perform their interwoven tasks, e.g. ATM, ATR, DNA-PK, Chk1, Chk2, PARP1/2/3, 53BP1, BRCA1, BRCA2, BLM, RAD51, and the MRE11-RAD50-NBS1 complex. Thus, the nature of the intricate coordination of repair processes with cell cycle progression is becoming apparent. This review also links molecular abnormalities to cellular pathology as much a possible and provides a framework of temporal relationships.
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Affiliation(s)
- Larry H Thompson
- Biology & Biotechnology Division, L452, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808, United States.
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It's all about position: the basal layer of human epidermis is particularly susceptible to different types of sunlight-induced DNA damage. J Invest Dermatol 2012; 132:265-7. [PMID: 22241442 DOI: 10.1038/jid.2011.281] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In this issue, Tewari et al. show that although UVB most effectively causes cyclobutane pyrimidine dimers (CPDs) at the human epidermal surface, UVA-induced CPDs predominate in the basal layer. Previous studies found higher accumulation of UVA-induced 8-oxo-7,8-dihydro-2'-deoxyguanosine and mutations in the basal layer. Therefore, the epidermal basal layer is particularly sensitive to UVA-induced genetic damage and the formation of mutations.
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Halliday GM, Byrne SN, Damian DL. Ultraviolet A Radiation: Its Role in Immunosuppression and Carcinogenesis. ACTA ACUST UNITED AC 2011; 30:214-21. [DOI: 10.1016/j.sder.2011.08.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 08/07/2011] [Indexed: 11/29/2022]
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Farrell AW, Halliday GM, Lyons JG. Chromatin structure following UV-induced DNA damage-repair or death? Int J Mol Sci 2011; 12:8063-85. [PMID: 22174650 PMCID: PMC3233456 DOI: 10.3390/ijms12118063] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 10/05/2011] [Accepted: 10/31/2011] [Indexed: 12/15/2022] Open
Abstract
In eukaryotes, DNA is compacted into a complex structure known as chromatin. The unravelling of DNA is a crucial step in DNA repair, replication, transcription and recombination as this allows access to DNA for these processes. Failure to package DNA into the nucleosome, the individual unit of chromatin, can lead to genomic instability, driving a cell into apoptosis, senescence, or cellular proliferation. Ultraviolet (UV) radiation damage causes destabilisation of chromatin integrity. UV irradiation induces DNA damage such as photolesions and subjects the chromatin to substantial rearrangements, causing the arrest of transcription forks and cell cycle arrest. Highly conserved processes known as nucleotide and base excision repair (NER and BER) then begin to repair these lesions. However, if DNA repair fails, the cell may be forced into apoptosis. The modification of various histones as well as nucleosome remodelling via ATP-dependent chromatin remodelling complexes are required not only to repair these UV-induced DNA lesions, but also for apoptosis signalling. Histone modifications and nucleosome remodelling in response to UV also lead to the recruitment of various repair and pro-apoptotic proteins. Thus, the way in which a cell responds to UV irradiation via these modifications is important in determining its fate. Failure of these DNA damage response steps can lead to cellular proliferation and oncogenic development, causing skin cancer, hence these chromatin changes are critical for a proper response to UV-induced injury.
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Affiliation(s)
- Andrew W Farrell
- Discipline of Dermatology, Bosch Institute, Sydney Cancer Centre, The University of Sydney, NSW 2006, Australia; E-Mails: (A.W.F.); (J.G.L.)
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Bock VL, Lyons JG, Huang XXJ, Jones AM, McDonald LA, Scolyer RA, Moloney FJ, Barnetson RS, Halliday GM. BRM and BRG1 subunits of the SWI/SNF chromatin remodelling complex are downregulated upon progression of benign skin lesions into invasive tumours. Br J Dermatol 2011; 164:1221-7. [PMID: 21564052 DOI: 10.1111/j.1365-2133.2011.10267.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Background Nonmelanoma skin cancer is caused by exposure to ultraviolet radiation within sunlight. Actinic keratoses (AKs) are benign precursor lesions that can develop into invasive squamous cell carcinoma (SCC). Little is known about the molecular events that lead to human skin cancer progression from benign to invasive. Objectives To determine novel genes that may be involved in skin cancer progression based on data from an initial microarray screen of human skin cancers. Methods The SWI/SNF chromatin remodelling ATPase subunit BRM was identified as being downregulated in SCC but not AK compared with normal skin in our microarray screen. Therefore reverse transcription-polymerase chain reaction, gene methylation and protein expression was used to study BRM and its alternative ATPase subunit BRG1 in a range of human skin cancers. Results We found reduced levels of mRNA coding for BRM but not BRG1 in SCC. BRM mRNA levels in AK were similar to those in normal skin. Deregulation of BRM did not result from hypermethylation of CpG regions in the promoter of these genes. Both BRM and BRG1 protein was reduced by about 10-fold in 100% of SCC and basal cell carcinoma, but not in AK specimens examined. Conclusions BRM protein may be decreased due to low levels of mRNA, while BRG1 protein loss appears to be post-translational. BRM and BRG1 may be novel tumour suppressor genes for human skin cancer. They appear to be involved after development of benign lesions, and are downregulated during progression towards invasion.
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Affiliation(s)
- V L Bock
- Discipline of Dermatology, Bosch Institute, Sydney Cancer Centre, University of Sydney, Sydney, NSW 2006, Australia
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28
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Abstract
Basal cell carcinoma is the most common human malignancy in populations of European origin, and Australia has the highest incidence of basal cell carcinoma in the world. Great advances in the understanding of the genetics of this cancer have occurred in recent years. Mutations of the patched 1 gene (PTCH1) lead to basal cell carcinoma predisposition in Gorlin syndrome. PTCH1 is part of the hedgehog signalling pathway, and derangements within this pathway are now known to be important in the carcinogenesis of many different cancers including sporadic basal cell carcinoma. The molecular biology of the hedgehog pathway is discussed, and mouse models of basal cell carcinoma based on this pathway are explored. New developments in non-surgical treatment of basal cell carcinoma are based on this knowledge. Other genes of importance to basal cell carcinoma development include the tumour suppressor gene P53 and the melanocortin-1 receptor gene. In addition, we discuss molecules of possible importance such as the glutathione-S-transferases, DNA repair genes, cyclin-dependent kinase inhibitor 2A, Brahma and connexins. Evidence of familial aggregation of this cancer is explored and supports the possibility of genetic predisposition to this common malignancy.
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Affiliation(s)
- Sally E de Zwaan
- Department of Dermatology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
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29
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Abstract
The discovery that cancer can be governed above and beyond the level of our DNA presents a new era for designing therapies that reverse the epigenetic state of a tumour cell. Understanding how altered chromatin dynamics leads to malignancy is essential for controlling tumour cells while sparing normal cells. Polycomb and trithorax group proteins are evolutionarily conserved and maintain chromatin in the 'off' or 'on' states, thereby preventing or promoting gene expression, respectively. Recent work highlights the dynamic interplay between these opposing classes of proteins, providing new avenues for understanding how these epigenetic regulators function in tumorigenesis.
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Affiliation(s)
- Alea A Mills
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA.
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30
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[What's new in dermatological research?]. Ann Dermatol Venereol 2010; 136 Suppl 7:S407-16. [PMID: 20110056 DOI: 10.1016/s0151-9638(09)73382-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Fundamental research in Dermatology has been once more very active during the past year and more specifically focused on immunological grounds of inflammatory diseases, the identification of risk loci associated with psoriasis and tumors, cutaneous lymphomas and on the genodermatosis where large international collaborative studies provided with a molecular understanding of an increasing amount of conditions especially affecting pigmentation and differentiation. In silico investigations become increasingly prominent especially with the rising power of new actor, China, the demographical and resulting epidemiological weight of which can hardly be challenged. Some of these fundamental breakthroughs might result in practical interventions although in an undefined future.
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Wang X, Sansam CG, Thom CS, Metzger D, Evans JA, Nguyen PTL, Roberts CWM. Oncogenesis caused by loss of the SNF5 tumor suppressor is dependent on activity of BRG1, the ATPase of the SWI/SNF chromatin remodeling complex. Cancer Res 2009; 69:8094-101. [PMID: 19789351 DOI: 10.1158/0008-5472.can-09-0733] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Alterations in chromatin play an important role in oncogenic transformation, although the underlying mechanisms are often poorly understood. The SWI/SNF complex contributes to epigenetic regulation by using the energy of ATP hydrolysis to remodel chromatin and thus regulate transcription of target genes. SNF5, a core subunit of the SWI/SNF complex, is a potent tumor suppressor that is specifically inactivated in several types of human cancer. However, the mechanism by which SNF5 mutation leads to cancer and the role of SNF5 within the SWI/SNF complex remain largely unknown. It has been hypothesized that oncogenesis in the absence of SNF5 occurs due to a loss of function of the SWI/SNF complex. Here, we show, however, distinct effects for inactivation of Snf5 and the ATPase subunit Brg1 in primary cells. Further, using both human cell lines and mouse models, we show that cancer formation in the absence of SNF5 does not result from SWI/SNF inactivation but rather that oncogenesis is dependent on continued presence of BRG1. Collectively, our results show that cancer formation in the absence of SNF5 is dependent on the activity of the residual BRG1-containing SWI/SNF complex. These findings suggest that, much like the concept of oncogene addiction, targeted inhibition of SWI/SNF ATPase activity may be an effective therapeutic approach for aggressive SNF5-deficient human tumors.
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Affiliation(s)
- Xi Wang
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Children's Hospital Boston, Boston, Massachusetts 02115, USA
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32
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Bergren SK, Rutter ED, Kearney JA. Fine mapping of an epilepsy modifier gene on mouse Chromosome 19. Mamm Genome 2009; 20:359-66. [PMID: 19513789 DOI: 10.1007/s00335-009-9193-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Accepted: 05/08/2009] [Indexed: 11/25/2022]
Abstract
Mutations in voltage-gated sodium channels are associated with several types of human epilepsy. Variable expressivity and penetrance are common features of inherited epilepsy caused by sodium channel mutations, suggesting that genetic modifiers may influence clinical severity. The mouse model Scn2a(Q54) has an epilepsy phenotype due to a mutation in Scn2a that results in elevated persistent sodium current. Phenotype severity in Scn2a(Q54) mice is dependent on the genetic background. Congenic C57BL/6J.Q54 mice have delayed onset and low seizure frequency compared to (C57BL/6J x SJL/J)F1.Q54 mice. Previously, we identified two modifier loci that influence the Scn2a(Q54) epilepsy phenotype: Moe1 (modifier of epilepsy 1) on Chromosome 11 and Moe2 on Chromosome 19. We have constructed interval-specific congenic strains to further refine the position of Moe2 on Chromosome 19 to a 5-Mb region. Sequencing and expression analyses of genes in the critical interval suggested two potential modifier candidates: (1) voltage-gated potassium channel subunit subfamily V, member 2 (Kcnv2), and (2) SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 2 (Smarca2). Based on its biological role in regulating membrane excitability and the association between ion channel variants and seizures, Kcnv2 is a strong functional candidate for Moe2. Modifier genes affecting the epilepsy phenotype of Scn2a(Q54) mice may contribute to variable expressivity and penetrance in human epilepsy patients with sodium channel mutations.
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Affiliation(s)
- Sarah K Bergren
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
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