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Prakash R, Izraely S, Thareja NS, Lee RH, Rappaport M, Kawaguchi R, Sagi-Assif O, Ben-Menachem S, Meshel T, Machnicki M, Ohe S, Hoon DS, Coppola G, Witz IP, Carmichael ST. Regeneration Enhances Metastasis: A Novel Role for Neurovascular Signaling in Promoting Melanoma Brain Metastasis. Front Neurosci 2019; 13:297. [PMID: 31024232 PMCID: PMC6465799 DOI: 10.3389/fnins.2019.00297] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 03/15/2019] [Indexed: 12/12/2022] Open
Abstract
Neural repair after stroke involves initiation of a cellular proliferative program in the form of angiogenesis, neurogenesis, and molecular growth signals in the surrounding tissue elements. This cellular environment constitutes a niche in which regeneration of new blood vessels and new neurons leads to partial tissue repair after stroke. Cancer metastasis has similar proliferative cellular events in the brain and other organs. Do cancer and CNS tissue repair share similar cellular processes? In this study, we identify a novel role of the regenerative neurovascular niche induced by stroke in promoting brain melanoma metastasis through enhancing cellular interactions with surrounding niche components. Repair-mediated neurovascular signaling induces metastatic cells to express genes crucial to metastasis. Mimicking stroke-like conditions in vitro displays an enhancement of metastatic migration potential and allows for the determination of cell-specific signals produced by the regenerative neurovascular niche. Comparative analysis of both in vitro and in vivo expression profiles reveals a major contribution of endothelial cells in mediating melanoma metastasis. These results point to a previously undiscovered role of the regenerative neurovascular niche in shaping the tumor microenvironment and brain metastatic landscape.
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Affiliation(s)
- Roshini Prakash
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Sivan Izraely
- Department of Cell Research and Immunology, School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Nikita S Thareja
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Rex H Lee
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Maya Rappaport
- Department of Cell Research and Immunology, School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Riki Kawaguchi
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, United States
| | - Orit Sagi-Assif
- Department of Cell Research and Immunology, School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Shlomit Ben-Menachem
- Department of Cell Research and Immunology, School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Tsipi Meshel
- Department of Cell Research and Immunology, School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Michal Machnicki
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Shuichi Ohe
- Department of Translational Molecular Medicine, John Wayne Cancer Institute at Providence Saint John's Health Center, Santa Monica, CA, United States
| | - Dave S Hoon
- Department of Translational Molecular Medicine, John Wayne Cancer Institute at Providence Saint John's Health Center, Santa Monica, CA, United States
| | - Giovanni Coppola
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, United States
| | - Isaac P Witz
- Department of Cell Research and Immunology, School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - S Thomas Carmichael
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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2
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Micevic G, Thakral D, McGeary M, Bosenberg MW. PD-L1 methylation regulates PD-L1 expression and is associated with melanoma survival. Pigment Cell Melanoma Res 2018; 32:435-440. [PMID: 30343532 DOI: 10.1111/pcmr.12745] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 08/30/2018] [Accepted: 10/01/2018] [Indexed: 11/27/2022]
Abstract
The aim of this study is to determine the significance of programmed death ligand 1 (PD-L1 or CD274) methylation in relation to PD-L1 expression and survival in melanoma. Despite the clinical importance of therapies targeting the PD-1/PD-L1 immune checkpoint in melanoma, factors regulating PD-L1 expression, including epigenetic mechanisms, are not completely understood. In this study, we examined PD-L1 promoter methylation in relation to PD-L1 expression and overall survival in melanoma patients. Our results suggest that DNA methylation regulates PD-L1 expression in melanoma, and we identify the key methylated CpG loci in the PD-L1 promoter, establish PD-L1 methylation as an independent survival prognostic factor, provide proof of concept for altering PD-L1 expression by hypomethylating agents, and uncover that PD-L1 methylation is associated with an interferon signaling transcriptional phenotype. Based on our findings, measuring and altering PD-L1 promoter DNA methylation may have potential prognostic and therapeutic applications in melanoma.
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Affiliation(s)
- Goran Micevic
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut.,Department of Dermatology, Yale School of Medicine, New Haven, Connecticut
| | - Durga Thakral
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut
| | - Meaghan McGeary
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut
| | - Marcus W Bosenberg
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut.,Department of Dermatology, Yale School of Medicine, New Haven, Connecticut
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Rudolf J, Raad H, Taieb A, Rezvani HR. NADPH Oxidases and Their Roles in Skin Homeostasis and Carcinogenesis. Antioxid Redox Signal 2018; 28:1238-1261. [PMID: 28990413 DOI: 10.1089/ars.2017.7282] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
SIGNIFICANCE Skin protects the body from dehydration, pathogens, and external mutagens. NADPH oxidases are central components for regulating the cellular redox balance. There is increasing evidence indicating that reactive oxygen species (ROS) generated by members of this enzyme family play important roles in the physiology and pathophysiology of the skin. Recent Advances: NADPH oxidases are active producers of ROS such as superoxide and hydrogen peroxide. Different isoforms are found in virtually all tissues. They play pivotal roles in normal cell homeostasis and in the cellular responses to various stressors. In particular, these enzymes are integral parts of redox-sensitive prosurvival and proapoptotic signaling pathways, in which they act both as effectors and as modulators. However, continuous (re)activation of NADPH oxidases can disturb the redox balance of cells, in the worst-case scenario in a permanent manner. Abnormal NADPH oxidase activity has been associated with a wide spectrum of diseases, as well as with aging and carcinogenesis. CRITICAL ISSUES Sunlight with its beneficial and deleterious effects induces the activation of NADPH oxidases in the skin. Evidence for the important roles of this enzyme family in skin cancer and skin aging, as well as in many chronic skin diseases, is now emerging. FUTURE DIRECTIONS Understanding the precise roles of NADPH oxidases in normal skin homeostasis, in the cellular responses to solar radiation, and during carcinogenesis will pave the way for their validation as therapeutic targets not only for the prevention and treatment of skin cancers but also for many other skin-related disorders. Antioxid. Redox Signal. 28, 1238-1261.
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Affiliation(s)
- Jana Rudolf
- 1 Inserm U 1035, Bordeaux, France .,2 Université de Bordeaux , Bordeaux, France
| | - Houssam Raad
- 1 Inserm U 1035, Bordeaux, France .,2 Université de Bordeaux , Bordeaux, France
| | - Alain Taieb
- 1 Inserm U 1035, Bordeaux, France .,2 Université de Bordeaux , Bordeaux, France .,3 Service de Dermatologie Adulte et Pédiatrique , CHU de Bordeaux, Bordeaux, France .,4 Centre de Référence des Maladies Rares de la Peau , CHU de Bordeaux, Bordeaux, France
| | - Hamid Reza Rezvani
- 1 Inserm U 1035, Bordeaux, France .,2 Université de Bordeaux , Bordeaux, France .,4 Centre de Référence des Maladies Rares de la Peau , CHU de Bordeaux, Bordeaux, France
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Budden T, van der Westhuizen A, Bowden NA. Sequential decitabine and carboplatin treatment increases the DNA repair protein XPC, increases apoptosis and decreases proliferation in melanoma. BMC Cancer 2018; 18:100. [PMID: 29373959 PMCID: PMC5787239 DOI: 10.1186/s12885-018-4010-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 01/21/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Melanoma has two key features, an over-representation of UV-induced mutations and resistance to DNA damaging chemotherapy agents. Both of these features may result from dysfunction of the nucleotide excision repair pathway, in particular the DNA damage detection branch, global genome repair (GGR). The key GGR component XPC does not respond to DNA damage in melanoma, the cause of this lack of response has not been investigated. In this study, we investigated the role of methylation in reduced XPC in melanoma. METHODS To reduce methylation and induce DNA-damage, melanoma cell lines were treated with decitabine and carboplatin, individually and sequentially. Global DNA methylation levels, XPC mRNA and protein expression and methylation of the XPC promoter were examined. Apoptosis, cell proliferation and senescence were also quantified. XPC siRNA was used to determine that the responses seen were reliant on XPC induction. RESULTS Treatment with high-dose decitabine resulted in global demethylation, including the the shores of the XPC CpG island and significantly increased XPC mRNA expression. Lower, clinically relevant dose of decitabine also resulted in global demethylation including the CpG island shores and induced XPC in 50% of cell lines. Decitabine followed by DNA-damaging carboplatin treatment led to significantly higher XPC expression in 75% of melanoma cell lines tested. Combined sequential treatment also resulted in a greater apoptotic response in 75% of cell lines compared to carboplatin alone, and significantly slowed cell proliferation, with some melanoma cell lines going into senescence. Inhibiting the increased XPC using siRNA had a small but significant negative effect, indicating that XPC plays a partial role in the response to sequential decitabine and carboplatin. CONCLUSIONS Demethylation using decitabine increased XPC and apoptosis after sequential carboplatin. These results confirm that sequential decitabine and carboplatin requires further investigation as a combination treatment for melanoma.
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Affiliation(s)
- Timothy Budden
- Hunter Medical Research Institute and Faculty of Health, University of Newcastle, Newcastle, NSW, Australia
| | | | - Nikola A Bowden
- Hunter Medical Research Institute and Faculty of Health, University of Newcastle, Newcastle, NSW, Australia.
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5
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Insights into ligand stimulation effects on gastro-intestinal stromal tumors signalling. Cell Signal 2017; 29:138-149. [DOI: 10.1016/j.cellsig.2016.10.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 10/14/2016] [Accepted: 10/18/2016] [Indexed: 01/24/2023]
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6
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Capaldo BJ, Roller D, Axelrod MJ, Koeppel AF, Petricoin EF, Slingluff CL, Weber MJ, Mackey AJ, Gioeli D, Bekiranov S. Systems Analysis of Adaptive Responses to MAP Kinase Pathway Blockade in BRAF Mutant Melanoma. PLoS One 2015; 10:e0138210. [PMID: 26405815 PMCID: PMC4583389 DOI: 10.1371/journal.pone.0138210] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 08/27/2015] [Indexed: 12/31/2022] Open
Abstract
Fifty percent of cutaneous melanomas are driven by activated BRAFV600E, but tumors treated with RAF inhibitors, even when they respond dramatically, rapidly adapt and develop resistance. Thus, there is a pressing need to identify the major mechanisms of intrinsic and adaptive resistance and develop drug combinations that target these resistance mechanisms. In a combinatorial drug screen on a panel of 12 treatment-naïve BRAFV600E mutant melanoma cell lines of varying levels of resistance to mitogen-activated protein kinase (MAPK) pathway inhibition, we identified the combination of PLX4720, a targeted inhibitor of mutated BRaf, and lapatinib, an inhibitor of the ErbB family of receptor tyrosine kinases, as synergistically cytotoxic in the subset of cell lines that displayed the most resistance to PLX4720. To identify potential mechanisms of resistance to PLX4720 treatment and synergy with lapatinib treatment, we performed a multi-platform functional genomics analysis to profile the genome as well as the transcriptional and proteomic responses of these cell lines to treatment with PLX4720. We found modest levels of resistance correlated with the zygosity of the BRAF V600E allele and receptor tyrosine kinase (RTK) mutational status. Layered over base-line resistance was substantial upregulation of many ErbB pathway genes in response to BRaf inhibition, thus generating the vulnerability to combination with lapatinib. The transcriptional responses of ErbB pathway genes are associated with a number of transcription factors, including ETS2 and its associated cofactors that represent a convergent regulatory mechanism conferring synergistic drug susceptibility in the context of diverse mutational landscapes.
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Affiliation(s)
- Brian J. Capaldo
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, United States of America
| | - Devin Roller
- Department of Microbiology, Immunology, and Cancer, University of Virginia, Charlottesville, Virginia, United States of America
| | - Mark J. Axelrod
- Department of Microbiology, Immunology, and Cancer, University of Virginia, Charlottesville, Virginia, United States of America
| | - Alex F. Koeppel
- Bioinfomatics Core Facility, University of Virginia, Charlottesville, Virginia, United States of America
| | - Emanuel F. Petricoin
- Center for Applied Proteomics and Molecular Medicine, School of Systems Biology, College of Science, George Mason University, Manassas, Virginia, United States of America
| | - Craig L. Slingluff
- Department of Surgery, University of Virginia, Charlottesville, Virginia, United States of America
| | - Michael J. Weber
- Department of Microbiology, Immunology, and Cancer, University of Virginia, Charlottesville, Virginia, United States of America
| | - Aaron J. Mackey
- Center for Public Health Genomics, University of Virginia, Charlottesville, Virginia, United States of America
| | - Daniel Gioeli
- Department of Microbiology, Immunology, and Cancer, University of Virginia, Charlottesville, Virginia, United States of America
| | - Stefan Bekiranov
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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Abstract
INTRODUCTION Advancements in epigenetic treatments are not only coming from new drugs, but also from modifications or encapsulation of the existing drugs into different formulations leading to greater stability and enhanced delivery to the target site. The epigenome is highly regulated and complex; therefore, it is important that off-target effects of epigenetic drugs be minimized. The step from in vitro to in vivo treatment of these drugs often requires development of a method of effective delivery for clinical translation. AREAS COVERED This review covers epigenetic mechanisms such as DNA methylation, chromatin remodeling and small-RNA-mediated gene regulation. There is a section in the review with examples of diseases where epigenetic alterations lead to impaired pathways, with an emphasis on cancer. Epigenetic drugs, their targets and clinical status are presented. Advantages of using a delivery method for epigenetic drugs as well as examples of current advancements and challenges are also discussed. EXPERT OPINION Epigenetic drugs have the potential to be very effective therapy against a number of diseases, especially cancers and neurological disorders. As with many chemotherapeutics, undesired side effects need to be minimized. Finding a suitable delivery method means reducing side effects and achieving a higher therapeutic index. Each drug may require a unique delivery method exploiting the drug's chemistry or other physical characteristic requiring interdisciplinary participation and would benefit from a better understanding of the mechanisms of action.
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Affiliation(s)
- Samantha A Cramer
- Lerner Research Institute, Cleveland Clinic, Department of Biomedical Engineering/ND20 , 9500 Euclid Avenue, Cleveland, OH 44195 , USA +1 216 445 9364 ; +1 216 444 9198 ;
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8
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Saraf S, Araki H, Petro B, Park Y, Taioli S, Yoshinaga KG, Koca E, Rondelli D, Mahmud N. Ex vivo expansion of human mobilized peripheral blood stem cells using epigenetic modifiers. Transfusion 2014; 55:864-74. [PMID: 25363624 DOI: 10.1111/trf.12904] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 09/02/2014] [Accepted: 09/02/2014] [Indexed: 12/21/2022]
Abstract
BACKGROUND Epigenetic modifications likely control the fate of hematopoietic stem cells (HSCs). The chromatin-modifying agents (CMAs), 5-aza-2'-deoxycytidine (5azaD) and trichostatin A (TSA), have previously been shown to expand HSCs from cord blood and marrow. Here we assessed whether CMA can also expand HSCs present in growth factor-mobilized human peripheral blood (MPB). STUDY DESIGN AND METHODS 5azaD and TSA were sequentially added to CD34+ MPB cells in the presence of cytokines, and the cells were cultured for 9 days. RESULTS After culture, a 3.6 ± 0.5-fold expansion of CD34+CD90+ cells, a 10.1 ± 0.5-fold expansion of primitive colony-forming unit (CFU)-mix, and a 2.2 ± 0.5-fold expansion of long-term cobblestone-area-forming cells (CAFCs) was observed in 5azaD/TSA-expanded cells. By contrast, cells cultured in cytokines without 5azaD/TSA displayed no expansion; rather, a reduction in CD34+CD90+ cells (0.7 ± 0.1-fold) and CAFCs (0.3 ± 0.1-fold) from their initial numbers was observed. Global hypomethylation corresponding with increased transcript levels of several genes implicated in HSC self-renewal, including HOXB4, GATA2, and EZH2, was observed in 5azaD/TSA-expanded MPB cells in contrast to controls. 5azaD/TSA-expanded MPB cells retained in vivo hematopoietic engraftment capacity. CONCLUSION MPB CD34+ cells from donors can be expanded using 5azaD/TSA, and these expanded cells retain in vivo hematopoietic reconstitution capacity. This strategy may prove to be potentially useful to augment HSC numbers for patients who fail to mobilize.
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Affiliation(s)
- Santosh Saraf
- Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois.,University of Illinois Cancer Center, Chicago, Illinois
| | - Hiroto Araki
- Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Benjamin Petro
- Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Youngmin Park
- UI Hospital Stem Cell Laboratory, Blood & Marrow Transplant Program, Chicago, Illinois
| | - Simona Taioli
- Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Kazumi G Yoshinaga
- Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Emre Koca
- Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Damiano Rondelli
- Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois.,UI Hospital Stem Cell Laboratory, Blood & Marrow Transplant Program, Chicago, Illinois.,University of Illinois Cancer Center, Chicago, Illinois
| | - Nadim Mahmud
- Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois.,UI Hospital Stem Cell Laboratory, Blood & Marrow Transplant Program, Chicago, Illinois.,University of Illinois Cancer Center, Chicago, Illinois
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Kleemann B, Loos B, Scriba TJ, Lang D, Davids LM. St John's Wort (Hypericum perforatum L.) photomedicine: hypericin-photodynamic therapy induces metastatic melanoma cell death. PLoS One 2014; 9:e103762. [PMID: 25076130 PMCID: PMC4116257 DOI: 10.1371/journal.pone.0103762] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 07/01/2014] [Indexed: 12/24/2022] Open
Abstract
Hypericin, an extract from St John's Wort (Hypericum perforatum L.), is a promising photosensitizer in the context of clinical photodynamic therapy due to its excellent photosensitizing properties and tumoritropic characteristics. Hypericin-PDT induced cytotoxicity elicits tumor cell death by various mechanisms including apoptosis, necrosis and autophagy-related cell death. However, limited reports on the efficacy of this photomedicine for the treatment of melanoma have been published. Melanoma is a highly aggressive tumor due to its metastasizing potential and resistance to conventional cancer therapies. The aim of this study was to investigate the response mechanisms of melanoma cells to hypericin-PDT in an in vitro tissue culture model. Hypericin was taken up by all melanoma cells and partially co-localized to the endoplasmic reticulum, mitochondria, lysosomes and melanosomes, but not the nucleus. Light activation of hypericin induced a rapid, extensive modification of the tubular mitochondrial network into a beaded appearance, loss of structural details of the endoplasmic reticulum and concomitant loss of hypericin co-localization. Surprisingly the opposite was found for lysosomal-related organelles, suggesting that the melanoma cells may be using these intracellular organelles for hypericin-PDT resistance. In line with this speculation we found an increase in cellular granularity, suggesting an increase in pigmentation levels in response to hypericin-PDT. Pigmentation in melanoma is related to a melanocyte-specific organelle, the melanosome, which has recently been implicated in drug trapping, chemotherapy and hypericin-PDT resistance. However, hypericin-PDT was effective in killing both unpigmented (A375 and 501mel) and pigmented (UCT Mel-1) melanoma cells by specific mechanisms involving the externalization of phosphatidylserines, cell shrinkage and loss of cell membrane integrity. In addition, this treatment resulted in extrinsic (A375) and intrinsic (UCT Mel-1) caspase-dependent apoptotic modes of cell death, as well as a caspase-independent apoptotic mode that did not involve apoptosis-inducing factor (501 mel). Further research is needed to shed more light on these mechanisms.
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Affiliation(s)
- Britta Kleemann
- Redox Laboratory and Confocal and Light Microscope Imaging Facility, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Benjamin Loos
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Thomas J. Scriba
- South African TB Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine and School of Child and Adolescent Health, University of Cape Town, Cape Town, South Africa
| | - Dirk Lang
- Redox Laboratory and Confocal and Light Microscope Imaging Facility, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Lester M. Davids
- Redox Laboratory and Confocal and Light Microscope Imaging Facility, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- * E-mail:
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TGF-β-Induced (TGFBI) Protein in Melanoma: A Signature of High Metastatic Potential. J Invest Dermatol 2014; 134:1675-1685. [DOI: 10.1038/jid.2014.20] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 12/03/2013] [Accepted: 12/16/2013] [Indexed: 12/20/2022]
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Terse P, Engelke K, Chan K, Ling Y, Sharpnack D, Saunthararajah Y, Covey JM. Subchronic oral toxicity study of decitabine in combination with tetrahydrouridine in CD-1 mice. Int J Toxicol 2014; 33:75-85. [PMID: 24639139 PMCID: PMC4001115 DOI: 10.1177/1091581814524994] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Decitabine (5-aza-2'-deoxycytidine; DAC) in combination with tetrahydrouridine (THU) is a potential oral therapy for sickle cell disease and β-thalassemia. A study was conducted in mice to assess safety of this combination therapy using oral gavage of DAC and THU administered 1 hour prior to DAC on 2 consecutive days/week for up to 9 weeks followed by a 28-day recovery to support its clinical trials up to 9-week duration. Tetrahydrouridine, a competitive inhibitor of cytidine deaminase, was used in the combination to improve oral bioavailability of DAC. Doses were 167 mg/kg THU followed by 0, 0.2, 0.4, or 1.0 mg/kg DAC; THU vehicle followed by 1.0 mg/kg DAC; or vehicle alone. End points evaluated were clinical observations, body weights, food consumption, clinical pathology, gross/histopathology, bone marrow micronuclei, and toxicokinetics. There were no treatment-related effects noticed on body weight, food consumption, serum chemistry, or urinalysis parameters. Dose- and gender-dependent changes in plasma DAC levels were observed with a Cmax within 1 hour. At the 1 mg/kg dose tested, THU increased DAC plasma concentration (∼ 10-fold) as compared to DAC alone. Severe toxicity occurred in females receiving high-dose 1 mg/kg DAC + THU, requiring treatment discontinuation at week 5. Severity and incidence of microscopic findings increased in a dose-dependent fashion; findings included bone marrow hypocellularity (with corresponding hematologic changes and decreases in white blood cells, red blood cells, hemoglobin, hematocrit, reticulocytes, neutrophils, and lymphocytes), thymic/lymphoid depletion, intestinal epithelial apoptosis, and testicular degeneration. Bone marrow micronucleus analysis confirmed bone marrow cytotoxicity, suppression of erythropoiesis, and genotoxicity. Following the recovery period, a complete or trend toward resolution of these effects was observed. In conclusion, the combination therapy resulted in an increased sensitivity to DAC toxicity correlating with DAC plasma levels, and females are more sensitive compared to their male counterparts.
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Affiliation(s)
- Pramod Terse
- Division of Pre-Clinical Innovations, National Center for Advancing Translational Sciences, Bethesda, MD, USA.
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12
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NeuroD1 regulation of migration accompanies the differential sensitivity of neuroendocrine carcinomas to TrkB inhibition. Oncogenesis 2013; 2:e63. [PMID: 23958853 PMCID: PMC3759124 DOI: 10.1038/oncsis.2013.24] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 06/07/2013] [Accepted: 06/13/2013] [Indexed: 01/09/2023] Open
Abstract
The developmental transcription factor NeuroD1 is anomalously expressed in a subset of aggressive neuroendocrine tumors. Previously, we demonstrated that TrkB and neural cell adhesion molecule (NCAM) are downstream targets of NeuroD1 that contribute to the actions of neurogenic differentiation 1 (NeuroD1) in neuroendocrine lung. We found that several malignant melanoma and prostate cell lines express NeuroD1 and TrkB. Inhibition of TrkB activity decreased invasion in several neuroendocrine pigmented melanoma but not in prostate cell lines. We also found that loss of the tumor suppressor p53 increased NeuroD1 expression in normal human bronchial epithelial cells and cancer cells with neuroendocrine features. Although we found that a major mechanism of action of NeuroD1 is by the regulation of TrkB, effective targeting of TrkB to inhibit invasion may depend on the cell of origin. These findings suggest that NeuroD1 is a lineage-dependent oncogene acting through its downstream target, TrkB, across multiple cancer types, which may provide new insights into the pathogenesis of neuroendocrine cancers.
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Evans P, Avey S, Kong Y, Krauthammer M. Adjusting for background mutation frequency biases improves the identification of cancer driver genes. IEEE Trans Nanobioscience 2013; 12:150-7. [PMID: 23694700 DOI: 10.1109/tnb.2013.2263391] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A common goal of tumor sequencing projects is finding genes whose mutations are selected for during tumor development. This is accomplished by choosing genes that have more non-synonymous mutations than expected from an estimated background mutation frequency. While this background frequency is unknown, it can be estimated using both the observed synonymous mutation frequency and the non-synonymous to synonymous mutation ratio. The synonymous mutation frequency can be determined across all genes or in a gene-specific manner. This choice introduces an interesting trade-off. A gene-specific frequency adjusts for an underlying mutation bias, but is difficult to estimate given missing synonymous mutation counts. Using a genome-wide synonymous frequency is more robust, but is less suited for adjusting biases. Studying four evaluation criteria for identifying genes with high non-synonymous mutation burden (reflecting preferential selection of expressed genes, genes with mutations in conserved bases, genes with many protein interactions, and genes that show loss of heterozygosity), we find that the gene-specific synonymous frequency is superior in the gene expression and protein interaction tests. In conclusion, the use of the gene-specific synonymous mutation frequency is well suited for assessing a gene's non-synonymous mutation burden.
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Affiliation(s)
- Perry Evans
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06511, USA
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Lim SP, Kumar R, Akkamsetty Y, Wang W, Ho K, Neilsen PM, Walther DJ, Suetani RJ, Prestidge C, Callen DF. Development of a novel cell-based assay system EPISSAY for screening epigenetic drugs and liposome formulated decitabine. BMC Cancer 2013; 13:113. [PMID: 23497118 PMCID: PMC3637807 DOI: 10.1186/1471-2407-13-113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 03/05/2013] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Despite the potential of improving the delivery of epigenetic drugs, the subsequent assessment of changes in their epigenetic activity is largely dependent on the availability of a suitable and rapid screening bioassay. Here, we describe a cell-based assay system for screening gene reactivation. METHODS A cell-based assay system (EPISSAY) was designed based on a silenced triple-mutated bacterial nitroreductase TMnfsB fused with Red-Fluorescent Protein (RFP) expressed in the non-malignant human breast cell line MCF10A. EPISSAY was validated using the target gene TXNIP, which has previously been shown to respond to epigenetic drugs. The potency of a epigenetic drug model, decitabine, formulated with PEGylated liposomes was also validated using this assay system. RESULTS Following treatment with DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors such as decitabine and vorinostat, increases in RFP expression were observed, indicating expression of RFP-TMnfsB. The EPISSAY system was then used to test the potency of decitabine, before and after PEGylated liposomal encapsulation. We observed a 50% higher potency of decitabine when encapsulated in PEGylated liposomes, which is likely to be due to its protection from rapid degradation. CONCLUSIONS The EPISSAY bioassay system provides a novel and rapid system to compare the efficiencies of existing and newly formulated drugs that reactivate gene expression.
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Affiliation(s)
- Sue Ping Lim
- Cancer Therapeutics Laboratory, Centre for Personalized Cancer Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Raman Kumar
- Cancer Therapeutics Laboratory, Centre for Personalized Cancer Medicine, The University of Adelaide, Adelaide, South Australia, Australia
- Women’s & Children’s Health Research Institute Inc, North Adelaide, South Australia, Australia
| | - Yamini Akkamsetty
- Ian Wark Research Institute, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, South Australia, Australia
| | - Wen Wang
- Ian Wark Research Institute, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, South Australia, Australia
| | - Kristen Ho
- Cancer Therapeutics Laboratory, Centre for Personalized Cancer Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Paul M Neilsen
- Cancer Therapeutics Laboratory, Centre for Personalized Cancer Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Diego J Walther
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Rachel J Suetani
- Cancer Therapeutics Laboratory, Centre for Personalized Cancer Medicine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Clive Prestidge
- Ian Wark Research Institute, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, South Australia, Australia
| | - David F Callen
- Cancer Therapeutics Laboratory, Centre for Personalized Cancer Medicine, The University of Adelaide, Adelaide, South Australia, Australia
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15
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Ebrahem Q, Mahfouz RZ, Ng KP, Saunthararajah Y. High cytidine deaminase expression in the liver provides sanctuary for cancer cells from decitabine treatment effects. Oncotarget 2013; 3:1137-45. [PMID: 23087155 PMCID: PMC3717944 DOI: 10.18632/oncotarget.597] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
We document for the first time that sanctuary in an organ which expresses high levels of the enzyme cytidine deaminase (CDA) is a mechanism of cancer cell resistance to cytidine analogues. This mechanism could explain why historically, cytidine analogues have not been successful chemotherapeutics against hepatotropic cancers, despite efficacy in vitro. Importantly, this mechanism of resistance can be readily reversed, without increasing toxicity to sensitive organs, by combining cytidine analogue with an inhibitor of cytidine deaminase (tetrahydrouridine). Specifically, CDA rapidly metabolizes cytidine analogues into inactive uridine counterparts. Hence, to determine if sheltering/protection of cancer cells in organs which express high levels of CDA (e.g., liver) is a mechanism of resistance, we utilized a murine xenotransplant model of myeloid cancer that is sensitive to epigenetic therapeutic effects of the cytidine analogue decitabine in vitro and hepato-tropic in vivo. Treatment of tumor-bearing mice with decitabine (subcutaneous 0.2mg/kg 2X/week) doubled median survival and significantly decreased extra-hepatic tumor burden, but hepatic tumor burden remained substantial, to which the animals eventually succumbed. Combining a clinically-relevant inhibitor of CDA (tetrahydrouridine) with a lower dose of decitabine (subcutaneous 0.1mg/kg 2X/week) markedly decreased liver tumor burden without blood count or bone marrow evidence of myelotoxicity, and with further improvement in survival. In conclusion, sanctuary in a CDA-rich organ is a mechanism by which otherwise susceptible cancer cells can resist the effects of decitabine epigenetic therapy. This protection can be reversed without increasing myelotoxicity by combining tetrahydrouridine with a lower dose of decitabine.
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Affiliation(s)
- Quteba Ebrahem
- Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
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16
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Mahfouz RZ, Jankowska A, Ebrahem Q, Gu X, Visconte V, Tabarroki A, Terse P, Covey J, Chan K, Ling Y, Engelke KJ, Sekeres MA, Tiu R, Maciejewski J, Radivoyevitch T, Saunthararajah Y. Increased CDA expression/activity in males contributes to decreased cytidine analog half-life and likely contributes to worse outcomes with 5-azacytidine or decitabine therapy. Clin Cancer Res 2013; 19:938-48. [PMID: 23287564 PMCID: PMC3577958 DOI: 10.1158/1078-0432.ccr-12-1722] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
PURPOSE The cytidine analogs 5-azacytidine and decitabine, used to treat myelodysplastic syndromes (MDS), produce a molecular epigenetic effect, depletion of DNA-methyltransferase 1 (DNMT1). This action is S-phase dependent. Hence, genetic factors that decrease the half-lives of these drugs could impact efficacy. Documentation of such impact, and elucidation of underlying mechanisms, could lead to improved clinical application. EXPERIMENTAL DESIGN Cytidine deaminase (CDA) rapidly inactivates 5-azacytidine/decitabine. The effect of CDA SNP A79C and gender on CDA expression, enzyme activity, and drug pharmacokinetics/pharmacodynamics was examined in mice and humans, and the impact on overall survival (OS) was evaluated in 5-azacytidine/decitabine-treated patients with MDS (n = 90) and cytarabine-treated patients with acute myeloid leukemia (AML) (n = 76). RESULTS By high-performance liquid chromatography (HPLC), plasma CDA activity was decreased as expected in individuals with the SNP A79C. Interestingly and significantly, there was an even larger decrease in females than in males. Explaining this decrease, liver CDA expression was significantly lower in female versus male mice. As expected, decitabine plasma levels, measured by mass spectrometry, were significantly higher in females. In mathematical modeling, the detrimental impact of shorter drug half-life (e.g., in males) was greater in low compared with high S-phase fraction disease (e.g., MDS vs. AML), because in high S-phase fraction disease, even a short exposure treats a major portion of cells. Accordingly, in multivariate analysis, OS was significantly worse in male versus female patients with MDS treated with 5-azacytidine/decitabine. CONCLUSIONS Increased CDA expression/activity in males contributes to decreased cytidine analog half-life and likely contributes to worse outcomes with 5-azacytidine or decitabine therapy.
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Affiliation(s)
- Reda Z Mahfouz
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Ania Jankowska
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Quteba Ebrahem
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Xiaorong Gu
- NCTT, Division of Pre-Clinical Innovations, National Center for Advancing Translational Sciences, NIH, Bethesda, Maryland
| | - Valeria Visconte
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Ali Tabarroki
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Pramod Terse
- NCTT, Division of Pre-Clinical Innovations, National Center for Advancing Translational Sciences, NIH, Bethesda, Maryland
| | - Joseph Covey
- Toxicology and Pharmacology Branch, Developmental Therapeutics Program, Division of Cancer Treatment and diagnosis, NCI, NIH, Bethesda, Maryland
| | - Kenneth Chan
- College of Pharmacy, The Ohio State University, Columbus, Ohio
| | - Yonghua Ling
- College of Pharmacy, The Ohio State University, Columbus, Ohio
| | | | - Mikkael A. Sekeres
- Department of Hematologic Oncology and Blood Disorders, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Ramon Tiu
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
- Department of Hematologic Oncology and Blood Disorders, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Jaroslaw Maciejewski
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
- Department of Hematologic Oncology and Blood Disorders, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Tomas Radivoyevitch
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio
| | - Yogen Saunthararajah
- Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
- Department of Hematologic Oncology and Blood Disorders, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
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17
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Lendvai Á, Johannes F, Grimm C, Eijsink JJH, Wardenaar R, Volders HH, Klip HG, Hollema H, Jansen RC, Schuuring E, Wisman GBA, van der Zee AGJ. Genome-wide methylation profiling identifies hypermethylated biomarkers in high-grade cervical intraepithelial neoplasia. Epigenetics 2012; 7:1268-78. [PMID: 23018867 DOI: 10.4161/epi.22301] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Epigenetic modifications, such as aberrant DNA promoter methylation, are frequently observed in cervical cancer. Identification of hypermethylated regions allowing discrimination between normal cervical epithelium and high-grade cervical intraepithelial neoplasia (CIN2/3), or worse, may improve current cervical cancer population-based screening programs. In this study, the DNA methylome of high-grade CIN lesions was studied using genome-wide DNA methylation screening to identify potential biomarkers for early diagnosis of cervical neoplasia. Methylated DNA Immunoprecipitation (MeDIP) combined with DNA microarray was used to compare DNA methylation profiles of epithelial cells derived from high-grade CIN lesions with normal cervical epithelium. Hypermethylated differentially methylated regions (DMRs) were identified. Validation of nine selected DMRs using BSP and MSP in cervical tissue revealed methylation in 63.2-94.7% high-grade CIN and in 59.3-100% cervical carcinomas. QMSP for the two most significant high-grade CIN-specific methylation markers was conducted exploring test performance in a large series of cervical scrapings. Frequency and relative level of methylation were significantly different between normal and cancer samples. Clinical validation of both markers in cervical scrapings from patients with an abnormal cervical smear confirmed that frequency and relative level of methylation were related with increasing severity of the underlying CIN lesion and that ROC analysis was discriminative. These markers represent the COL25A1 and KATNAL2 and their observed increased methylation upon progression could intimate the regulatory role in carcinogenesis. In conclusion, our newly identified hypermethylated DMRs represent specific DNA methylation patterns in high-grade CIN lesions and are candidate biomarkers for early detection.
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Affiliation(s)
- Ágnes Lendvai
- Department of Gynaecological Oncology, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
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18
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Exome sequencing identifies recurrent somatic RAC1 mutations in melanoma. Nat Genet 2012; 44:1006-14. [PMID: 22842228 PMCID: PMC3432702 DOI: 10.1038/ng.2359] [Citation(s) in RCA: 893] [Impact Index Per Article: 74.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/28/2012] [Indexed: 02/06/2023]
Abstract
We characterized the mutational landscape of melanoma, the form of skin cancer with the highest mortality rate, by sequencing the exomes of 147 melanomas. Sun-exposed melanomas had markedly more ultraviolet (UV)-like C>T somatic mutations compared to sun-shielded acral, mucosal and uveal melanomas. Among the newly identified cancer genes was PPP6C, encoding a serine/threonine phosphatase, which harbored mutations that clustered in the active site in 12% of sun-exposed melanomas, exclusively in tumors with mutations in BRAF or NRAS. Notably, we identified a recurrent UV-signature, an activating mutation in RAC1 in 9.2% of sun-exposed melanomas. This activating mutation, the third most frequent in our cohort of sun-exposed melanoma after those of BRAF and NRAS, changes Pro29 to serine (RAC1P29S) in the highly conserved switch I domain. Crystal structures, and biochemical and functional studies of RAC1P29S showed that the alteration releases the conformational restraint conferred by the conserved proline, causes an increased binding of the protein to downstream effectors, and promotes melanocyte proliferation and migration. These findings raise the possibility that pharmacological inhibition of downstream effectors of RAC1 signaling could be of therapeutic benefit.
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19
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The epithelial-mesenchymal transition (EMT) regulatory factor SLUG (SNAI2) is a downstream target of SPARC and AKT in promoting melanoma cell invasion. PLoS One 2012; 7:e40378. [PMID: 22911700 PMCID: PMC3401237 DOI: 10.1371/journal.pone.0040378] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 06/04/2012] [Indexed: 12/25/2022] Open
Abstract
During progression of melanoma, malignant melanocytes can be reprogrammed into mesenchymal-like cells through a process similar to epithelial-mesenchymal transition (EMT), which is associated with downregulation of the junctional protein E-cadherin and acquisition of a migratory phenotype. Recent evidence supports a role for SLUG, a transcriptional repressor of E-cadherin, as a melanocyte lineage transcription factor that predisposes to melanoma metastasis. However, the signals responsible for SLUG expression in melanoma are unclear and its role in the invasive phenotype is not fully elucidated. Here, we report that SLUG expression and activation is driven by SPARC (also known as osteonectin), a secreted extracellular matrix-associated factor that promotes EMT-like changes. Ectopic expression or knockdown of SPARC resulted in increased or reduced expression of SLUG, respectively. SLUG increase occurred concomitantly with SPARC-mediated downregulation of E-cadherin and P-cadherin, and induction of mesenchymal traits in human melanocytes and melanoma cells. Pharmacological blockade of PI3 kinase/AKT signaling impeded SPARC-induced SLUG levels and cell migration, whereas adenoviral introduction of constitutively active AKT allowed rescue of SLUG and migratory capabilities of SPARC knockdown cells. We also observed that pharmacological inhibition of oncogenic BRAFV600E using PLX4720 did not influence SLUG expression in melanoma cells harboring BRAFV600E. Furthermore, SLUG is a bona fide transcriptional repressor of E-cadherin as well as a regulator of P-cadherin in melanoma cells and its knockdown attenuated invasive behavior and blocked SPARC-enhanced cell migration. Notably, inhibition of cell migration in SPARC-depleted cells was rescued by expression of a SLUG transgene. In freshly isolated metastatic melanoma cells, a positive association between SPARC and SLUG mRNA levels was also found. These findings reveal that autocrine SPARC maintains heightened SLUG expression in melanoma cells and indicate that SPARC may promote EMT-associated tumor invasion by supporting AKT-dependent upregulation of SLUG.
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20
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Alcazar O, Achberger S, Aldrich W, Hu Z, Negrotto S, Saunthararajah Y, Triozzi P. Epigenetic regulation by decitabine of melanoma differentiation in vitro and in vivo. Int J Cancer 2012; 131:18-29. [PMID: 21796622 PMCID: PMC3454528 DOI: 10.1002/ijc.26320] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 06/07/2011] [Accepted: 07/01/2011] [Indexed: 01/20/2023]
Abstract
Apoptosis genes, such as TP53 and p16/CDKN2A, that mediate responses to cytotoxic chemotherapy, are frequently nonfunctional in melanoma. Differentiation may be an alternative to apoptosis for inducing melanoma cell cycle exit. Epigenetic mechanisms regulate differentiation, and DNA methylation alterations are associated with the abnormal differentiation of melanoma cells. The effects of the deoxycytidine analogue decitabine (5-aza-2'-deoxycytidine), which depletes DNA methyl transferase 1 (DNMT1), on melanoma differentiation were examined. Treatment of human and murine melanoma cells in vitro with concentrations of decitabine that did not cause apoptosis inhibited proliferation accompanied by cellular differentiation. A decrease in promoter methylation, and increase in expression of the melanocyte late-differentiation driver SOX9, was followed by increases in cyclin-dependent kinase inhibitors (CDKN) p27/CDKN1B and p21/CDKN1A that mediate cell cycle exit with differentiation. Effects were independent of the TP53, p16/CDKN2A and also the BRAF status of the melanoma cells. Resistance, when observed, was pharmacologic, characterized by diminished ability of decitabine to deplete DNMT1. Treatment of murine melanoma models in vivo with intermittent, low-dose decitabine, administered sub-cutaneously to limit high peak drug levels that cause cytotoxicity and increase exposure time for DNMT1 depletion, and with tetrahydrouridine to decrease decitabine metabolism and further increase exposure time, inhibited tumor growth and increased molecular and tumor stromal factors implicated in melanocyte differentiation. Modification of decitabine dose, schedule and formulation for differentiation rather than cytotoxic objectives inhibits the growth of melanoma cells in vitro and in vivo.
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MESH Headings
- Animals
- Antimetabolites, Antineoplastic/pharmacology
- Apoptosis
- Azacitidine/administration & dosage
- Azacitidine/analogs & derivatives
- Azacitidine/pharmacology
- Base Sequence
- Cell Differentiation/drug effects
- Cell Line, Tumor
- Cell Proliferation/drug effects
- Cyclin-Dependent Kinase Inhibitor Proteins/biosynthesis
- Cyclin-Dependent Kinase Inhibitor p16/metabolism
- DNA (Cytosine-5-)-Methyltransferase 1
- DNA (Cytosine-5-)-Methyltransferases/analysis
- DNA (Cytosine-5-)-Methyltransferases/metabolism
- DNA Methylation
- Decitabine
- Epigenesis, Genetic
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- Male
- Melanoma, Experimental/drug therapy
- Melanoma, Experimental/genetics
- Melanoma, Experimental/metabolism
- Melanoma, Experimental/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Nude
- Promoter Regions, Genetic/genetics
- Proto-Oncogene Proteins B-raf/biosynthesis
- SOX9 Transcription Factor/biosynthesis
- Sequence Analysis, DNA
- Tetrahydrouridine/pharmacology
- Tumor Suppressor Protein p53/metabolism
- Up-Regulation
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Affiliation(s)
- Oscar Alcazar
- Taussig Cancer Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Susan Achberger
- Taussig Cancer Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Wayne Aldrich
- Taussig Cancer Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Zhenbo Hu
- Taussig Cancer Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Soledad Negrotto
- Taussig Cancer Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
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21
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Hassler MR, Klisaroska A, Kollmann K, Steiner I, Bilban M, Schiefer AI, Sexl V, Egger G. Antineoplastic activity of the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine in anaplastic large cell lymphoma. Biochimie 2012; 94:2297-307. [PMID: 22687603 PMCID: PMC3480637 DOI: 10.1016/j.biochi.2012.05.029] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 05/31/2012] [Indexed: 12/31/2022]
Abstract
DNA methylation is an epigenetic mechanism establishing long-term gene silencing during development and cell commitment, which is maintained in subsequent cell generations. Aberrant DNA methylation is found at gene promoters in most cancers and can lead to silencing of tumor suppressor genes. The DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (5-aza-CdR) is able to reactivate genes silenced by DNA methylation and has been shown to be a very potent epigenetic drug in several hematological malignancies. In this report, we demonstrate that 5-aza-CdR exhibits high antineoplastic activity against anaplastic large cell lymphoma (ALCL), a rare CD30 positive non-Hodgkin lymphoma of T-cell origin. Low dose treatment of ALCL cell lines and xenografted tumors causes apoptosis and cell cycle arrest in vitro and in vivo. This is also reflected in genome-wide expression analyses, where genes related to apoptosis and cell death are amongst the most affected targets of 5-aza-CdR. Furthermore, we observed demethylation and re-expression of p16INK4A after drug administration and senescence associated β-galactosidase activity. Thus, our data provide evidence that 5-aza-CdR is highly efficient against ALCL and warrants further clinical evaluation for future therapeutic use.
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Affiliation(s)
- Melanie R Hassler
- Clinical Institute of Pathology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
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22
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Cell cycle gene networks are associated with melanoma prognosis. PLoS One 2012; 7:e34247. [PMID: 22536322 PMCID: PMC3335030 DOI: 10.1371/journal.pone.0034247] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 02/24/2012] [Indexed: 11/19/2022] Open
Abstract
Background Our understanding of the molecular pathways that underlie melanoma remains incomplete. Although several published microarray studies of clinical melanomas have provided valuable information, we found only limited concordance between these studies. Therefore, we took an in vitro functional genomics approach to understand melanoma molecular pathways. Methodology/Principal Findings Affymetrix microarray data were generated from A375 melanoma cells treated in vitro with siRNAs against 45 transcription factors and signaling molecules. Analysis of this data using unsupervised hierarchical clustering and Bayesian gene networks identified proliferation-association RNA clusters, which were co-ordinately expressed across the A375 cells and also across melanomas from patients. The abundance in metastatic melanomas of these cellular proliferation clusters and their putative upstream regulators was significantly associated with patient prognosis. An 8-gene classifier derived from gene network hub genes correctly classified the prognosis of 23/26 metastatic melanoma patients in a cross-validation study. Unlike the RNA clusters associated with cellular proliferation described above, co-ordinately expressed RNA clusters associated with immune response were clearly identified across melanoma tumours from patients but not across the siRNA-treated A375 cells, in which immune responses are not active. Three uncharacterised genes, which the gene networks predicted to be upstream of apoptosis- or cellular proliferation-associated RNAs, were found to significantly alter apoptosis and cell number when over-expressed in vitro. Conclusions/Significance This analysis identified co-expression of RNAs that encode functionally-related proteins, in particular, proliferation-associated RNA clusters that are linked to melanoma patient prognosis. Our analysis suggests that A375 cells in vitro may be valid models in which to study the gene expression modules that underlie some melanoma biological processes (e.g., proliferation) but not others (e.g., immune response). The gene expression modules identified here, and the RNAs predicted by Bayesian network inference to be upstream of these modules, are potential prognostic biomarkers and drug targets.
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23
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Lavelle D, Vaitkus K, Ling Y, Ruiz MA, Mahfouz R, Ng KP, Negrotto S, Smith N, Terse P, Engelke KJ, Covey J, Chan KK, Desimone J, Saunthararajah Y. Effects of tetrahydrouridine on pharmacokinetics and pharmacodynamics of oral decitabine. Blood 2012; 119:1240-7. [PMID: 22160381 PMCID: PMC3277356 DOI: 10.1182/blood-2011-08-371690] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 12/05/2011] [Indexed: 12/24/2022] Open
Abstract
The deoxycytidine analog decitabine (DAC) can deplete DNA methyl-transferase 1 (DNMT1) and thereby modify cellular epigenetics, gene expression, and differentiation. However, a barrier to efficacious and accessible DNMT1-targeted therapy is cytidine deaminase, an enzyme highly expressed in the intestine and liver that rapidly metabolizes DAC into inactive uridine counterparts, severely limiting exposure time and oral bioavailability. In the present study, the effects of tetrahydrouridine (THU), a competitive inhibitor of cytidine deaminase, on the pharmacokinetics and pharmacodynamics of oral DAC were evaluated in mice and nonhuman primates. Oral administration of THU before oral DAC extended DAC absorption time and widened the concentration-time profile, increasing the exposure time for S-phase-specific depletion of DNMT1 without the high peak DAC levels that can cause DNA damage and cytotoxicity. THU also decreased interindividual variability in pharmacokinetics seen with DAC alone. One potential clinical application of DNMT1-targeted therapy is to increase fetal hemoglobin and treat hemoglobinopathy. Oral THU-DAC at a dose that would produce peak DAC concentrations of less than 0.2μM administered 2×/wk for 8 weeks to nonhuman primates was not myelotoxic, hypomethylated DNA in the γ-globin gene promoter, and produced large cumulative increases in fetal hemoglobin. Combining oral THU with oral DAC changes DAC pharmacology in a manner that may facilitate accessible noncytotoxic DNMT1-targeted therapy.
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Affiliation(s)
- Donald Lavelle
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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24
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Saunthararajah Y, Triozzi P, Rini B, Singh A, Radivoyevitch T, Sekeres M, Advani A, Tiu R, Reu F, Kalaycio M, Copelan E, Hsi E, Lichtin A, Bolwell B. p53-Independent, normal stem cell sparing epigenetic differentiation therapy for myeloid and other malignancies. Semin Oncol 2012; 39:97-108. [PMID: 22289496 PMCID: PMC3655437 DOI: 10.1053/j.seminoncol.2011.11.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cytotoxic chemotherapy for acute myeloid leukemia (AML) usually produces only temporary remissions, at the cost of significant toxicity and risk for death. One fundamental reason for treatment failure is that it is designed to activate apoptosis genes (eg, TP53) that may be unavailable because of mutation or deletion. Unlike deletion of apoptosis genes, genes that mediate cell cycle exit by differentiation are present in myelodysplastic syndrome (MDS) and AML cells but are epigenetically repressed: MDS/AML cells express high levels of key lineage-specifying transcription factors. Mutations in these transcription factors (eg, CEBPA) or their cofactors (eg., RUNX1) affect transactivation function and produce epigenetic repression of late-differentiation genes that antagonize MYC. Importantly, this aberrant epigenetic repression can be redressed clinically by depleting DNA methyltransferase 1 (DNMT1, a central component of the epigenetic network that mediates transcription repression) using the deoxycytidine analogue decitabine at non-cytotoxic concentrations. The DNMT1 depletion is sufficient to trigger upregulation of late-differentiation genes and irreversible cell cycle exit by p53-independent differentiation mechanisms. Fortuitously, the same treatment maintains or increases self-renewal of normal hematopoietic stem cells, which do not express high levels of lineage-specifying transcription factors. The biological rationale for this approach to therapy appears to apply to cancers other than MDS/AML also. Decitabine or 5-azacytidine dose and schedule can be rationalized to emphasize this mechanism of action, as an alternative or complement to conventional apoptosis-based oncotherapy.
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Affiliation(s)
- Yogen Saunthararajah
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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25
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Holford ME, McCusker JP, Cheung KH, Krauthammer M. A semantic web framework to integrate cancer omics data with biological knowledge. BMC Bioinformatics 2012; 13 Suppl 1:S10. [PMID: 22373303 PMCID: PMC3471346 DOI: 10.1186/1471-2105-13-s1-s10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The RDF triple provides a simple linguistic means of describing limitless types of information. Triples can be flexibly combined into a unified data source we call a semantic model. Semantic models open new possibilities for the integration of variegated biological data. We use Semantic Web technology to explicate high throughput clinical data in the context of fundamental biological knowledge. We have extended Corvus, a data warehouse which provides a uniform interface to various forms of Omics data, by providing a SPARQL endpoint. With the querying and reasoning tools made possible by the Semantic Web, we were able to explore quantitative semantic models retrieved from Corvus in the light of systematic biological knowledge. RESULTS For this paper, we merged semantic models containing genomic, transcriptomic and epigenomic data from melanoma samples with two semantic models of functional data - one containing Gene Ontology (GO) data, the other, regulatory networks constructed from transcription factor binding information. These two semantic models were created in an ad hoc manner but support a common interface for integration with the quantitative semantic models. Such combined semantic models allow us to pose significant translational medicine questions. Here, we study the interplay between a cell's molecular state and its response to anti-cancer therapy by exploring the resistance of cancer cells to Decitabine, a demethylating agent. CONCLUSIONS We were able to generate a testable hypothesis to explain how Decitabine fights cancer - namely, that it targets apoptosis-related gene promoters predominantly in Decitabine-sensitive cell lines, thus conveying its cytotoxic effect by activating the apoptosis pathway. Our research provides a framework whereby similar hypotheses can be developed easily.
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Somasundaram R, Villanueva J, Herlyn M. Intratumoral heterogeneity as a therapy resistance mechanism: role of melanoma subpopulations. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2012; 65:335-59. [PMID: 22959031 DOI: 10.1016/b978-0-12-397927-8.00011-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Malignant melanoma is an aggressive form of skin cancer whose incidence continues to increase worldwide. Increased exposure to sun, ultraviolet radiation, and the use of tanning beds can increase the risk of melanoma. Early detection of melanomas is the key to successful treatment mainly through surgical excision of the primary tumor lesion. But in advanced stage melanomas, once the disease has spread beyond the primary site to distant organs, the tumors are difficult to treat and quickly develop resistance to most available forms of therapy. The advent of molecular and cellular techniques has led to a better characterization of tumor cells revealing the presence of heterogeneous melanoma subpopulations. The discovery of gene mutations and alterations of cell-signaling pathways in melanomas has led to the development of new targeted drugs that show dramatic response rates in patients. Single-agent therapies generally target one subpopulation of tumor cells while leaving others unharmed. The surviving subpopulations will have the ability to repopulate the original tumors that can continue to progress. Thus, a rational approach to target multiple subpopulations of tumor cells with a combination of drugs instead of single-agent therapy will be necessary for long-lasting inhibition of melanoma lesions. In this context, the recent development of immune checkpoint reagents provides an additional armor that can be used in combination with targeted drugs to expand the presence of melanoma reactive T cells in circulation to prevent tumor recurrence.
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Affiliation(s)
- Rajasekharan Somasundaram
- Molecular and Cellular Oncogenesis Program, Melanoma Research Center, The Wistar Institute, Philadelphia, USA
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Bonazzi VF, Nancarrow DJ, Stark MS, Moser RJ, Boyle GM, Aoude LG, Schmidt C, Hayward NK. Cross-platform array screening identifies COL1A2, THBS1, TNFRSF10D and UCHL1 as genes frequently silenced by methylation in melanoma. PLoS One 2011; 6:e26121. [PMID: 22028813 PMCID: PMC3197591 DOI: 10.1371/journal.pone.0026121] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 09/20/2011] [Indexed: 12/15/2022] Open
Abstract
Epigenetic regulation of tumor suppressor genes (TSGs) has been shown to play a central role in melanomagenesis. By integrating gene expression and methylation array analysis we identified novel candidate genes frequently methylated in melanoma. We validated the methylation status of the most promising genes using highly sensitive Sequenom Epityper assays in a large panel of melanoma cell lines and resected melanomas, and compared the findings with those from cultured melanocytes. We found transcript levels of UCHL1, COL1A2, THBS1 and TNFRSF10D were inversely correlated with promoter methylation. For THBS1 and UCHL1 the effect of this methylation on expression was confirmed at the protein level. Identification of these candidate TSGs and future research designed to understand how their silencing is related to melanoma development will increase our understanding of the etiology of this cancer and may provide tools for its early diagnosis.
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Affiliation(s)
- Vanessa F Bonazzi
- Oncogenomics Laboratory, Queensland Institute of Medical Research, Herston, Brisbane, Queensland, Australia.
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28
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Karreth FA, Tay Y, Perna D, Ala U, Tan SM, Rust AG, DeNicola G, Webster KA, Weiss D, Perez-Mancera PA, Krauthammer M, Halaban R, Provero P, Adams DJ, Tuveson DA, Pandolfi PP. In vivo identification of tumor- suppressive PTEN ceRNAs in an oncogenic BRAF-induced mouse model of melanoma. Cell 2011; 147:382-95. [PMID: 22000016 PMCID: PMC3236086 DOI: 10.1016/j.cell.2011.09.032] [Citation(s) in RCA: 543] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/20/2011] [Accepted: 09/24/2011] [Indexed: 02/08/2023]
Abstract
We recently proposed that competitive endogenous RNAs (ceRNAs) sequester microRNAs to regulate mRNA transcripts containing common microRNA recognition elements (MREs). However, the functional role of ceRNAs in cancer remains unknown. Loss of PTEN, a tumor suppressor regulated by ceRNA activity, frequently occurs in melanoma. Here, we report the discovery of significant enrichment of putative PTEN ceRNAs among genes whose loss accelerates tumorigenesis following Sleeping Beauty insertional mutagenesis in a mouse model of melanoma. We validated several putative PTEN ceRNAs and further characterized one, the ZEB2 transcript. We show that ZEB2 modulates PTEN protein levels in a microRNA-dependent, protein coding-independent manner. Attenuation of ZEB2 expression activates the PI3K/AKT pathway, enhances cell transformation, and commonly occurs in human melanomas and other cancers expressing low PTEN levels. Our study genetically identifies multiple putative microRNA decoys for PTEN, validates ZEB2 mRNA as a bona fide PTEN ceRNA, and demonstrates that abrogated ZEB2 expression cooperates with BRAF(V600E) to promote melanomagenesis.
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Affiliation(s)
- Florian A. Karreth
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Yvonne Tay
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Daniele Perna
- Li-Ka Shing Centre, Cambridge Research Institute, CRUK, Robinson Way, Cambridge CB2 0RE, UK
| | - Ugo Ala
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
- Molecular Biotechnology Center and Department of Genetics, Biology and Biochemistry, University of Turin, Turin, Italy
| | - Shen Mynn Tan
- Immune Disease Institute and Program in Cellular and Molecular Medicine, Children's Hospital Boston, and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Alistair G. Rust
- Experimental Cancer Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, CB10 1HH, UK
| | - Gina DeNicola
- Division of Signal Transduction, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Kaitlyn A. Webster
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Dror Weiss
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Pedro A. Perez-Mancera
- Li-Ka Shing Centre, Cambridge Research Institute, CRUK, Robinson Way, Cambridge CB2 0RE, UK
| | | | - Ruth Halaban
- Department of Dermatology, Yale University, New Haven, CT 06520, USA
| | - Paolo Provero
- Molecular Biotechnology Center and Department of Genetics, Biology and Biochemistry, University of Turin, Turin, Italy
| | - David J. Adams
- Experimental Cancer Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, CB10 1HH, UK
| | - David A. Tuveson
- Li-Ka Shing Centre, Cambridge Research Institute, CRUK, Robinson Way, Cambridge CB2 0RE, UK
| | - Pier Paolo Pandolfi
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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Generation of reactive oxygen species during apoptosis induced by DNA-damaging agents and/or histone deacetylase inhibitors. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2011; 2011:253529. [PMID: 21949898 PMCID: PMC3178180 DOI: 10.1155/2011/253529] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 07/15/2011] [Accepted: 07/26/2011] [Indexed: 01/08/2023]
Abstract
Reactive oxygen species play an important role in the process of apoptosis in many cell types. In this paper, we analyzed the role of ROS in DNA-damaging agents (actinomycin D or decitabine), which induced apoptosis of leukemia cell line CML-T1 and normal peripheral blood lymphocytes (PBL). The possibility of synergism with histone deacetylase inhibitors butyrate or SAHA is also reported. We found that in cancer cell line, ROS production significantly contributed to apoptosis triggering, while in normal lymphocytes treated by cytostatic or cytotoxic drugs, necrosis as well as apoptosis occurred and large heterogeneity of ROS production was measured. Combined treatment with histone deacetylase inhibitor did not potentiate actinomycin D action, whereas combination of decitabine and SAHA brought synergistic ROS generation and apoptotic features in CML cell line. Appropriate decrease of cell viability indicated promising therapeutic potential of this combination in CML, but side effects on normal PBL should be taken into attention.
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Smith CC, Li B, Liu J, Lee KS, Aurelian L. The Levels of H11/HspB8 DNA methylation in human melanoma tissues and xenografts are a critical molecular marker for 5-Aza-2'-deoxycytidine therapy. Cancer Invest 2011; 29:383-95. [PMID: 21649464 PMCID: PMC3111925 DOI: 10.3109/07357907.2011.584588] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
H11/HspB8 is a functionally distinct small heat shock protein. It causes growth arrest in melanocytes, associated with the inhibition of Cyclin E/Cdk2 and β-catenin phosphorylation at the transcriptional activity site Ser(552) and is silenced through DNA methylation in 27/35 (77%) melanoma tissues/early cultures. 5-Aza-2'-deoxycytidine (Aza-C) induces melanoma cell death correlated with the levels of H11/HspB8 DNA methylation (p < .001). In line with low/moderate H11/HspB8 methylation, PI3-K inhibition increases Aza-C-induced cell death. Aza-C inhibits the growth of melanoma xenografts related to the levels of H11/HspB8 methylation, and a nonmethylated/non-TAK1 binding H11/HspB8 mutant confers Aza-C resistance. H11/HspB8 is a potential molecular marker for demethylation therapies.
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Affiliation(s)
- Cynthia C. Smith
- Department of Pharmacology and Experimental Therapeutics, University of Maryland, School of Medicine, 655 West Baltimore Street, Baltimore, Maryland 21201, USA
| | - Baiquan Li
- Department of Pharmacology and Experimental Therapeutics, University of Maryland, School of Medicine, 655 West Baltimore Street, Baltimore, Maryland 21201, USA
| | - Juan Liu
- Department of Pharmacology and Experimental Therapeutics, University of Maryland, School of Medicine, 655 West Baltimore Street, Baltimore, Maryland 21201, USA
| | - Kie-Sok Lee
- Department of Pharmacology and Experimental Therapeutics, University of Maryland, School of Medicine, 655 West Baltimore Street, Baltimore, Maryland 21201, USA
| | - Laure Aurelian
- Department of Pharmacology and Experimental Therapeutics, University of Maryland, School of Medicine, 655 West Baltimore Street, Baltimore, Maryland 21201, USA
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31
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p53 independent epigenetic-differentiation treatment in xenotransplant models of acute myeloid leukemia. Leukemia 2011; 25:1739-50. [PMID: 21701495 DOI: 10.1038/leu.2011.159] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Suppression of apoptosis by TP53 mutation contributes to resistance of acute myeloid leukemia (AML) to conventional cytotoxic treatment. Using differentiation to induce irreversible cell cycle exit in AML cells could be a p53-independent treatment alternative, however, this possibility requires evaluation. In vitro and in vivo regimens of the deoxycytidine analogue decitabine that deplete the chromatin-modifying enzyme DNA methyl-transferase 1 without phosphorylating p53 or inducing early apoptosis were determined. These decitabine regimens but not equimolar DNA-damaging cytarabine upregulated the key late differentiation factors CCAAT enhancer-binding protein ɛ and p27/cyclin dependent kinase inhibitor 1B (CDKN1B), induced cellular differentiation and terminated AML cell cycle, even in cytarabine-resistant p53- and p16/CDKN2A-null AML cells. Leukemia initiation by xenotransplanted AML cells was abrogated but normal hematopoietic stem cell engraftment was preserved. In vivo, the low toxicity allowed frequent drug administration to increase exposure, an important consideration for S phase specific decitabine therapy. In xenotransplant models of p53-null and relapsed/refractory AML, the non-cytotoxic regimen significantly extended survival compared with conventional cytotoxic cytarabine. Modifying in vivo dose and schedule to emphasize this pathway of decitabine action can bypass a mechanism of resistance to standard therapy.
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32
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Abstract
Ineffective erythropoiesis, the hallmark of β-thalassemia, is a result of α/non-α globin chain imbalance. One strategy to redress globin-chain imbalance is to induce γ-globin gene (HBG) expression. Repression of HBG in adult erythroid cells involves DNA methylation and other epigenetic changes. Therefore, the cytosine analog decitabine, which can deplete DNA methyltransferase 1 (DNMT1), can potentially activate HBG. In 5 patients with β-thalassemia intermedia, a dose and schedule of decitabine intended to deplete DNMT1 without causing significant cytotoxicity (0.2 mg/kg subcutaneous 2 times per week for 12 weeks) increased total hemoglobin from 7.88 ± 0.88 g/dL to 9.04 ± 0.77 g/dL (P = .004) and absolute fetal hemoglobin from 3.64 ± 1.13 g/dL to 4.29 ± 1.13 g/dL (P = .003). Significant favorable changes also occurred in indices of hemolysis and red blood cell densitometry. Consistent with a noncytotoxic, differentiation altering mechanism of action, the major side effect was an asymptomatic increase in platelet counts without erythrocyte micronucleus or VDJ recombination assay evidence of genotoxicity. This study was registered at www.clinicaltrials.gov as #NCT00661726.
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33
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Chan E, Patel R, Nallur S, Ratner E, Bacchiocchi A, Hoyt K, Szpakowski S, Godshalk S, Ariyan S, Sznol M, Halaban R, Krauthammer M, Tuck D, Slack FJ, Weidhaas JB. MicroRNA signatures differentiate melanoma subtypes. Cell Cycle 2011; 10:1845-52. [PMID: 21543894 DOI: 10.4161/cc.10.11.15777] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Melanoma is an aggressive cancer that is highly resistance to therapies once metastasized. We studied microRNA (miRNA) expression in clinical melanoma subtypes and evaluated different miRNA signatures in the background of gain of function somatic and inherited mutations associated with melanoma. Total RNA from 42 patient derived primary melanoma cell lines and three independent normal primary melanocyte cell cultures was evaluated by miRNA array. MiRNA expression was then analyzed comparing subtypes and additional clinicopathologic criteria including somatic mutations. The prevalence and association of an inherited variant in a miRNA binding site in the 3'UTR of the KRAS oncogene, referred to as the KRAS-variant, was also evaluated. We show that seven miRNAs, miR-142-3p, miR-486, miR-214, miR-218, miR-362, miR-650 and miR-31, were significantly correlated with acral as compared to non-acral melanomas (p < 0.04). In addition, we discovered that the KRAS-variant was enriched in non-acral melanoma (25%), and that miR-137 under expression was significantly associated with melanomas with the KRAS-variant. Our findings indicate that miRNAs are differentially expressed in melanoma subtypes and that their misregulation can be impacted by inherited gene variants, supporting the hypothesis that miRNA misregulation reflects biological differences in melanoma.
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Affiliation(s)
- Elcie Chan
- Yale University School of Medicine, New Haven, CT, USA
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34
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Tworkoski K, Singhal G, Szpakowski S, Zito CI, Bacchiocchi A, Muthusamy V, Bosenberg M, Krauthammer M, Halaban R, Stern DF. Phosphoproteomic screen identifies potential therapeutic targets in melanoma. Mol Cancer Res 2011; 9:801-12. [PMID: 21521745 DOI: 10.1158/1541-7786.mcr-10-0512] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Therapies directed against receptor tyrosine kinases are effective in many cancer subtypes, including lung and breast cancer. We used a phosphoproteomic platform to identify active receptor tyrosine kinases that might represent therapeutic targets in a panel of 25 melanoma cell strains. We detected activated receptors including TYRO3, AXL, MERTK, EPHB2, MET, IGF1R, EGFR, KIT, HER3, and HER4. Statistical analysis of receptor tyrosine kinase activation as well as ligand and receptor expression indicates that some receptors, such as FGFR3, may be activated via autocrine circuits. Short hairpin RNA knockdown targeting three of the active kinases identified in the screen, AXL, HER3, and IGF1R, inhibited the proliferation of melanoma cells and knockdown of active AXL also reduced melanoma cell migration. The changes in cellular phenotype observed on AXL knockdown seem to be modulated via the STAT3 signaling pathway, whereas the IGF1R-dependent alterations seem to be regulated by the AKT signaling pathway. Ultimately, this study identifies several novel targets for therapeutic intervention in melanoma.
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Affiliation(s)
- Kathryn Tworkoski
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
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35
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Godshalk SE, Paranjape T, Nallur S, Speed W, Chan E, Molinaro AM, Bacchiocchi A, Hoyt K, Tworkoski K, Stern DF, Sznol M, Ariyan S, Lazova R, Halaban R, Kidd KK, Weidhaas J, Slack FJ. A Variant in a MicroRNA complementary site in the 3' UTR of the KIT oncogene increases risk of acral melanoma. Oncogene 2011; 30:1542-50. [PMID: 21119596 PMCID: PMC3069149 DOI: 10.1038/onc.2010.536] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 09/15/2010] [Accepted: 10/07/2010] [Indexed: 01/14/2023]
Abstract
MicroRNAs (miRNAs) are small ∼22nt single stranded RNAs that negatively regulate protein expression by binding to partially complementary sequences in the 3' untranslated region (3' UTRs) of target gene messenger RNAs (mRNA). Recently, mutations have been identified in both miRNAs and target genes that disrupt regulatory relationships, contribute to oncogenesis and serve as biomarkers for cancer risk. KIT, an established oncogene with a multifaceted role in melanogenesis and melanoma pathogenesis, has recently been shown to be upregulated in some melanomas, and is also a target of the miRNA miR-221. Here, we describe a genetic variant in the 3' UTR of the KIT oncogene that correlates with a greater than fourfold increased risk of acral melanoma. This KIT variant results in a mismatch in the seed region of a miR-221 complementary site and reporter data suggests that this mismatch can result in increased expression of the KIT oncogene. Consistent with the hypothesis that this is a functional variant, KIT mRNA and protein levels are both increased in the majority of samples harboring the KIT variant. This work identifies a novel genetic marker for increased heritable risk of melanoma.
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Affiliation(s)
- Sirie E. Godshalk
- Department of Molecular, Cellular and Developmental Biology, Yale University
| | - Trupti Paranjape
- Department of Therapeutic Radiology, Yale University School of Medicine
| | - Sunitha Nallur
- Department of Therapeutic Radiology, Yale University School of Medicine
| | - William Speed
- Department of Genetics, Yale University School of Medicine
| | - Elcie Chan
- Department of Therapeutic Radiology, Yale University School of Medicine
| | | | | | - Kathleen Hoyt
- Department of Dermatology, Yale University School of Medicine
| | | | - David F. Stern
- Department of Pathology, Yale University School of Medicine
| | - Mario Sznol
- Section of Medical Oncology, Yale University School of Medicine
| | - Stephan Ariyan
- Department of Surgery, Yale University School of Medicine
| | - Rossitza Lazova
- Department of Dermatology, Yale University School of Medicine
| | - Ruth Halaban
- Department of Dermatology, Yale University School of Medicine
| | | | - Joanne Weidhaas
- Department of Therapeutic Radiology, Yale University School of Medicine
| | - Frank J. Slack
- Department of Molecular, Cellular and Developmental Biology, Yale University
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Negrotto S, Hu Z, Alcazar O, Ng KP, Triozzi P, Lindner D, Rini B, Saunthararajah Y. Noncytotoxic differentiation treatment of renal cell cancer. Cancer Res 2011; 71:1431-41. [PMID: 21303982 DOI: 10.1158/0008-5472.can-10-2422] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Current drug therapy for metastatic renal cell cancer (RCC) results in temporary disease control but not cure, necessitating continued investigation into alternative mechanistic approaches. Drugs that inhibit chromatin-modifying enzymes involved in transcription repression (chromatin-relaxing drugs) could have a role, by inducing apoptosis and/or through differentiation pathways. At low doses, the cytosine analogue decitabine (DAC) can be used to deplete DNA methyl-transferase 1 (DNMT1), modify chromatin, and alter differentiation without causing apoptosis (cytotoxicity). Noncytotoxic regimens of DAC were evaluated for in vitro and in vivo efficacy against RCC cell lines, including a p53-mutated RCC cell line developed from a patient with treatment-refractory metastatic RCC. The cell division-permissive mechanism of action-absence of early apoptosis or DNA damage, increase in expression of HNF4α (hepatocyte nuclear factor 4α), a key driver associated with the mesenchymal to epithelial transition, decrease in mesenchymal marker expression, increase in epithelial marker expression, and late increase in cyclin-dependent kinase inhibitor CDKN1B (p27) protein-was consistent with differentiation-mediated cell-cycle exit. In vivo blood counts and animal weights were consistent with minimal toxicity of therapy. The distinctive mechanism of action of a dose and schedule of DAC designed for noncytotoxic depletion of DNMT1 suggests a potential role in treating RCC.
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Affiliation(s)
- Soledad Negrotto
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio, USA
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37
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Fabiani E, Leone G, Giachelia M, D'alo' F, Greco M, Criscuolo M, Guidi F, Rutella S, Hohaus S, Voso MT. Analysis of genome-wide methylation and gene expression induced by 5-aza-2'-deoxycytidine identifies BCL2L10 as a frequent methylation target in acute myeloid leukemia. Leuk Lymphoma 2010; 51:2275-84. [PMID: 21077739 DOI: 10.3109/10428194.2010.528093] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Epigenetic changes play a role in the pathogenesis of myeloid malignancies, and hypomethylating agents have shown efficacy in these diseases. We studied the apoptotic effect, genome-wide methylation, and gene expression profiles in HL60 cells following 5-aza-2'-deoxycytidine (decitabine; DAC) treatment, using microarray technologies. Decitabine treatment resulted in a decrease in global DNA methylation, corresponding to 4876 probeset IDs with significantly reduced methylation levels, while the expression of 2583 IDs was modified. The integrated analysis identified 160 genes demethylated and up-regulated by decitabine, mainly including development and differentiation pathway genes. Gene targets of Polycomb group protein regulation were overrepresented in this group. Apoptosis was induced by decitabine, and apoptosis-specific PCR arrays more precisely indicated decitabine-induced up-regulation of 13 apoptosis-related genes, in particular DAP-kinase 1 and BCL2L10. Correspondingly, in primary patient samples, BCL2L10 was hypermethylated in 45% of AML, 43% of therapy-related myeloid neoplasms, 12% of MDS, and in none of the controls. In conclusion, decitabine induces global demethylation and gene expression, in particular of Polycomb target genes involved in development and differentiation pathways. The apoptotic gene BCL2L10 is a frequent target for aberrant promoter methylation in patients with acute leukemia, de novo and therapy-related.
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Affiliation(s)
- Emiliano Fabiani
- Istituto di Ematologia, Universita' Cattolica Sacro Cuore, Rome, Italy
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Abstract
Malignant melanoma remains one of the most deadly human cancers with no effective cures for metastatic disease. The poor efficacy of current therapy in advanced melanoma highlights the need for better understanding of molecular mechanisms contributing to the disease. Recent work has shown that epigenetic changes, including aberrant DNA methylation, lead to alterations in gene expression and are as important in the development of malignant melanoma as the specific and well-characterized genetic events. Reversion of these methylation patterns could thus lead to a more targeted therapy and are currently under clinical investigation. The purpose of this review is to compile recent information on aberrant DNA methylation of melanoma, to highlight key genes and molecular pathways in melanoma development, which have been found to be epigenetically altered and to provide insight as to how DNA methylation might serve as targeted treatment option as well as a molecular and prognostic marker in malignant melanoma.
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39
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Essa S, Denzer N, Mahlknecht U, Klein R, Collnot EM, Reichrath J. Challenge and promise: the role of miRNA for pathogenesis and progression of malignant melanoma. Clin Epigenetics 2010; 1:7-11. [PMID: 22704085 PMCID: PMC3365361 DOI: 10.1007/s13148-010-0001-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Accepted: 04/05/2010] [Indexed: 11/29/2022] Open
Abstract
microRNAs are endogenous noncoding RNAs that are implicated in gene regulation. More recently, miRNAs have been shown to play a pivotal role in multiple cellular processes that interfere with tumorigenesis. Here we summarize the essential role of microRNAs for human cancer with special focus on malignant melanoma and the promising perspectives for cancer therapies.
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Affiliation(s)
- Salma Essa
- Department of Dermatology, The Saarland University Hospital, 66421 Homburg, Germany
| | - N. Denzer
- Department of Dermatology, The Saarland University Hospital, 66421 Homburg, Germany
| | - U. Mahlknecht
- Department of Internal Medicine I, Saarland University Hospital, 66421 Homburg, Germany
| | - R. Klein
- Seq-It GmbH & Co. KG, 67655 Kaiserslautern, Germany
| | - E. M. Collnot
- Department of Biopharmaceutics and Pharmaceutical Technology, Saarland University, 66123 Saarbrücken, Germany
| | - J. Reichrath
- Department of Dermatology, The Saarland University Hospital, 66421 Homburg, Germany
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40
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Licchesi JDF, Van Neste L, Tiwari VK, Cope L, Lin X, Baylin SB, Herman JG. Transcriptional regulation of Wnt inhibitory factor-1 by Miz-1/c-Myc. Oncogene 2010; 29:5923-34. [PMID: 20697356 DOI: 10.1038/onc.2010.322] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The Wnt signaling pathway is capable of self-regulation through positive and negative feedback mechanisms. For example, the oncoprotein c-Myc, which is upregulated by Wnt signaling activity, participates in a positive feedback loop of canonical Wnt signaling through repression of Wnt antagonists DKK1 and SFRP1. In this study, we investigated the mechanism of Wnt inhibitory factor-1 (WIF-1) silencing. Mapping of CpG island methylation of the WIF-1 promoter reveals regional methylation (-295 to -95 bp from the transcription start site) that correlates with transcriptional silencing. We identified Miz-1 as a direct activator of WIF-1 transcriptional activity, which is found at WIF-1 promoter. In addition, we show that c-Myc contributes to WIF-1 transcriptional repression in a Miz-1-dependent manner. Although the transient repression mediated by Miz-1/c-Myc is independent of de novo methylation, the stable repression by this complex is associated with CpG island methylation of the critical -295 to -95-bp region of the WIF-1 promoter. Importantly, Miz-1 and c-Myc are found at WIF-1 promoter in WIF-1 non-expressing cell lines DLD-1 and 209myc. Transient knockdown or somatic knockout of c-Myc in DLD-1 failed to restore WIF-1 expression suggesting that c-Myc is involved in initiating rather than maintaining WIF-1 epigenetic silencing. In a genome-wide screen, DNAJA4, TGFβ-induced and TRIM59 were repressed by c-Myc overexpression and DNA promoter hypermethylation. Our data reveal novel insights into c-Myc-mediated DNA methylation-dependent transcriptional silencing, a mechanism that might contribute to the dysregulation of Wnt signaling in cancer.
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Affiliation(s)
- J D F Licchesi
- Cancer Biology Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD 21231, USA.
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Sigalotti L, Covre A, Fratta E, Parisi G, Colizzi F, Rizzo A, Danielli R, Nicolay HJM, Coral S, Maio M. Epigenetics of human cutaneous melanoma: setting the stage for new therapeutic strategies. J Transl Med 2010; 8:56. [PMID: 20540720 PMCID: PMC2901206 DOI: 10.1186/1479-5876-8-56] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 06/11/2010] [Indexed: 12/15/2022] Open
Abstract
Cutaneous melanoma is a very aggressive neoplasia of melanocytic origin with constantly growing incidence and mortality rates world-wide. Epigenetic modifications (i.e., alterations of genomic DNA methylation patterns, of post-translational modifications of histones, and of microRNA profiles) have been recently identified as playing an important role in melanoma development and progression by affecting key cellular pathways such as cell cycle regulation, cell signalling, differentiation, DNA repair, apoptosis, invasion and immune recognition. In this scenario, pharmacologic inhibition of DNA methyltransferases and/or of histone deacetylases were demonstrated to efficiently restore the expression of aberrantly-silenced genes, thus re-establishing pathway functions. In light of the pleiotropic activities of epigenetic drugs, their use alone or in combination therapies is being strongly suggested, and a particular clinical benefit might be expected from their synergistic activities with chemo-, radio-, and immuno-therapeutic approaches in melanoma patients. On this path, an important improvement would possibly derive from the development of new generation epigenetic drugs characterized by much reduced systemic toxicities, higher bioavailability, and more specific epigenetic effects.
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Affiliation(s)
- Luca Sigalotti
- Cancer Bioimmunotherapy Unit, Centro di Riferimento Oncologico, Istituto di Ricovero e Cura a Carattere Scientifico, Via F, Gallini 2, Aviano, Italy.
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Abstract
There is now a compelling body of evidences sustaining the importance of epigenetic mechanisms in the development and progression of cancer. DNA methylation, post-translational histone and other protein modifications, microRNA expression, and nucleosome positioning, all act together to exert their cellular effects. The epigenome is responsible for controlling gene expression thus defining cell differentiation and tissue specificity. This review will focus on DNA methylation and histone modification because these epigenetic events are widely implicated in cancer development and progression. We will in particular address the translational aspects of breast cancer epigenomics including the development of biomarkers and the prospects for epigenetic based pharmacologic treatments. The analysis of DNA methylation has the advantage over other molecular methods (e.g. single gene mutation, microsatellite analysis) that it can be detected with a very high degree of specificity even in the presence of excess unmethylated DNA. Furthermore, the presence of specific CpG methylation signatures makes methylation-based markers attractive diagnostic, prognostic, and predictive tools for better management of breast cancer patients.
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Affiliation(s)
- Paola Parrella
- Laboratorio di Oncologia, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy
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43
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Giuliano S, Cheli Y, Ohanna M, Bonet C, Beuret L, Bille K, Loubat A, Hofman V, Hofman P, Ponzio G, Bahadoran P, Ballotti R, Bertolotto C. Microphthalmia-Associated Transcription Factor Controls the DNA Damage Response and a Lineage-Specific Senescence Program in Melanomas. Cancer Res 2010; 70:3813-22. [DOI: 10.1158/0008-5472.can-09-2913] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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44
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Halaban R, Zhang W, Bacchiocchi A, Cheng E, Parisi F, Ariyan S, Krauthammer M, McCusker JP, Kluger Y, Sznol M. PLX4032, a selective BRAF(V600E) kinase inhibitor, activates the ERK pathway and enhances cell migration and proliferation of BRAF melanoma cells. Pigment Cell Melanoma Res 2010; 23:190-200. [PMID: 20149136 PMCID: PMC2848976 DOI: 10.1111/j.1755-148x.2010.00685.x] [Citation(s) in RCA: 267] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BRAFV600E/K is a frequent mutationally active tumor-specific kinase in melanomas that is currently targeted for therapy by the specific inhibitor PLX4032. Our studies with melanoma tumor cells that are BRAFV600E/K and BRAFWT showed that, paradoxically, while PLX4032 inhibited ERK1/2 in the highly sensitive BRAFV600E/K, it activated the pathway in the resistant BRAFWT cells, via RAF1 activation, regardless of the status of mutations in NRAS or PTEN. The persistently active ERK1/2 triggered downstream effectors in BRAFWT melanoma cells and induced changes in the expression of a wide-spectrum of genes associated with cell cycle control. Furthermore, PLX4032 increased the rate of proliferation of growth factor-dependent NRAS Q61L mutant primary melanoma cells, reduced cell adherence and increased mobility of cells from advanced lesions. The results suggest that the drug can confer an advantage to BRAFWT primary and metastatic tumor cells in vivo and provide markers for monitoring clinical responses.
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Affiliation(s)
- Ruth Halaban
- Department of Dermatology, Yale University School of Medicine, New Haven, CT, USA.
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45
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Rubinstein JC, Tran N, Ma S, Halaban R, Krauthammer M. Genome-wide methylation and expression profiling identifies promoter characteristics affecting demethylation-induced gene up-regulation in melanoma. BMC Med Genomics 2010; 3:4. [PMID: 20144234 PMCID: PMC2843643 DOI: 10.1186/1755-8794-3-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Accepted: 02/09/2010] [Indexed: 11/18/2022] Open
Abstract
Background Abberant DNA methylation at CpG dinucleotides represents a common mechanism of transcriptional silencing in cancer. Since CpG methylation is a reversible event, tumor supressor genes that have undergone silencing through this mechanism represent promising targets for epigenetically active anti-cancer therapy. The cytosine analog 5-aza-2'-deoxycytidine (decitabine) induces genomic hypomethylation by inhibiting DNA methyltransferase, and is an example of an epigenetic agent that is thought to act by up-regulating silenced genes. Methods It is unclear why decitabine causes some silenced loci to re-express, while others remain inactive. By applying data-mining techniques to large-scale datasets, we attempted to elucidate the qualities of promoter regions that define susceptibility to the drug's action. Our experimental data, derived from melanoma cell strains, consist of genome-wide gene expression data before and after treatment with decitabine, as well as genome-wide data on un-treated promoter methylation status, and validation of specific genes by bisulfite sequencing. Results We show that the combination of promoter CpG content and methylation level informs the ability of decitabine treatment to up-regulate gene expression. Promoters with high methylation levels and intermediate CpG content appear most susceptible to up-regulation by decitabine, whereas few of those highly methylated promoters with high CpG content are up-regulated. For promoters with low methylation levels, those with high CpG content are more likely to be up-regulated, whereas those with low CpG content are underrepresented among up-regulated genes. Conclusions Clinically, elucidating the patterns of action of decitabine could aid in predicting the likelihood of up-regulating epigenetically silenced tumor suppressor genes and others from pathways involved with tumor biology. As a first step toward an eventual translational application, we build a classifier to predict gene up-regulation based on promoter methylation and CpG content, which achieves a performance of 0.77 AUC.
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Affiliation(s)
- Jill C Rubinstein
- Interdepartmental Program in Computational Biology & Bioinformatics, Yale University, New Haven, CT 06520, USA
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Maddodi N, Bhat KMR, Devi S, Zhang SC, Setaluri V. Oncogenic BRAFV600E induces expression of neuronal differentiation marker MAP2 in melanoma cells by promoter demethylation and down-regulation of transcription repressor HES1. J Biol Chem 2009; 285:242-54. [PMID: 19880519 DOI: 10.1074/jbc.m109.068668] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
MAP2 is a neuron-specific microtubule-associated protein that binds and stabilizes dendritic microtubules. Previously, we showed that MAP2 expression is (a) activated in cutaneous primary melanoma and (b) inversely associated with melanoma tumor progression. We also showed that ectopic expression of MAP2 in metastatic melanoma cells inhibits cell growth by inducing mitotic spindle defects and apoptosis. However, molecular mechanisms of regulation of MAP2 gene expression in melanoma are not understood. Here, we show that in melanoma cells MAP2 expression is induced by the demethylating agent 5-aza-2'-cytidine, and MAP2 promoter is progressively methylated during melanoma progression, indicating that epigenetic mechanisms are involved in silencing of MAP2 in melanoma. In support of this, methylation of MAP2 promoter DNA in vitro inhibits its activity. Because MAP2 promoter activity levels in melanoma cell lines also correlated with activating mutation in BRAF, a gene that is highly expressed in neurons, we hypothesized that BRAF signaling is involved in MAP2 expression. We show that hyperactivation of BRAF-MEK signaling activates MAP2 expression in melanoma cells by two independent mechanisms, promoter demethylation or down-regulation of neuronal transcription repressor HES1. Our data suggest that BRAF oncogene levels can regulate melanoma neuronal differentiation and tumor progression.
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Affiliation(s)
- Nityanand Maddodi
- Department of Dermatology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
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Jilaveanu LB, Zito CR, Aziz SA, Conrad PJ, Schmitz JC, Sznol M, Camp RL, Rimm DL, Kluger HM. C-Raf is associated with disease progression and cell proliferation in a subset of melanomas. Clin Cancer Res 2009; 15:5704-13. [PMID: 19737955 DOI: 10.1158/1078-0432.ccr-09-0198] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PURPOSE Raf-kinases include three major isoforms. Although the role of B-Raf in melanoma is well established, little is known about C-Raf. We studied effects of C-Raf knockdown in vitro and assessed expression of C-Raf in a large cohort of melanomas and nevi. EXPERIMENTAL DESIGN Using specific siRNAs, we knocked down C-Raf expression, and determined the effect on viability, MAP extracellular signal-regulated kinase (ERK)/ERK kinase signaling, and apoptosis in seven melanoma cell lines. We determined the IC(50) of the C-Raf inhibitors sorafenib and GW5074, and studied the effects of GW5074 on cell signaling. Using an automated method to measure in situ protein expression, we quantified C-Raf expression in 263 nevi and 523 melanomas. RESULTS C-Raf was knocked down in three cell lines with detectable phospho-C-Raf, resulting in decreased viability in two of the three (YULAC and YUROB). This resulted in decreased Bcl-2 expression and phospho-Bad cleavage, without affecting phospho-MEK and phospho-ERK. Sensitivity to sorafenib and GW5074 varied. GW5074 inhibited mitogen-activated protein kinase signaling without Bcl-2 and phospho-Bad down-regulation. C-Raf was highly expressed in melanomas compared with nevi (P < 0.0001), and no nevi had high C-Raf expression. C-Raf expression was higher in metastatic than primary specimens (P = 0.0225). CONCLUSIONS C-Raf siRNA knock-down results in decreased viability of YULAC (B-Raf(V600K)) and YUROB (B-Raf(WT)) melanoma cells, likely mediated by Bcl-2 inhibition rather than mitogen-activated protein kinase inhibition. Cotargeting C-Raf and parallel pathways might be an effective therapeutic approach for melanoma. C-Raf expression is up-regulated in a subset of melanomas but not in nevi, suggesting that it might be a valuable diagnostic marker and therapeutic target.
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Affiliation(s)
- Lucia B Jilaveanu
- Yale Cancer Center and Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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5-Azacytidine facilitates osteogenic gene expression and differentiation of mesenchymal stem cells by alteration in DNA methylation. Cytotechnology 2009; 60:11. [PMID: 19557538 DOI: 10.1007/s10616-009-9203-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2008] [Accepted: 06/07/2009] [Indexed: 12/26/2022] Open
Abstract
Mesenchymal stem cells (MSCs) are considered to be one of the most promising therapeutic cell sources as they encompass a plasticity of multiple cell lineages. The challenge in using these cells lies in developing well-defined protocols for directing cellular differentiation to generate a desired lineage. In this study, we investigated the effect of 5-azacytidine, a DNA demethylating agent, on osteogenic differentiation of MSCs. The cells were exposed to 5-azacytidine in culture medium for 24 h prior to osteogenic induction. Osteogenic differentiation was determined by several the appearance of a number of osteogenesis characteristics, including gene expression, ALP activity, and calcium mineralization. Pretreatment of MSCs with 5-azacytidine significantly facilitated osteogenic differentiation and was accompanied by hypomethylation of genomic DNA and increased osteogenic gene expression. Taking dlx5 as a representative, methylation alterations of the "CpG island shore" in the promoter caused by 5-azacytidine appeared to contribute to osteogenic differentiation.
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49
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Koga Y, Pelizzola M, Cheng E, Krauthammer M, Sznol M, Ariyan S, Narayan D, Molinaro AM, Halaban R, Weissman SM. Genome-wide screen of promoter methylation identifies novel markers in melanoma. Genome Res 2009; 19:1462-70. [PMID: 19491193 DOI: 10.1101/gr.091447.109] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
DNA methylation is an important component of epigenetic modifications, which influences the transcriptional machinery aberrant in many human diseases. In this study we present the first genome-wide integrative analysis of promoter methylation and gene expression for the identification of methylation markers in melanoma. Genome-wide promoter methylation and gene expression of eight early-passage human melanoma cell strains were compared with newborn and adult melanocytes. We used linear mixed effect models (LME) in combination with a series of filters based on the localization of promoter methylation relative to the transcription start site, overall promoter CpG content, and differential gene expression to discover DNA methylation markers. This approach identified 76 markers, of which 68 were hyper- and eight hypomethylated (LME, P < 0.05). Promoter methylation and differential gene expression of five markers (COL1A2, NPM2, HSPB6, DDIT4L, MT1G) were validated by sequencing of bisulfite-modified DNA and real-time reverse transcriptase PCR, respectively. Importantly, the incidence of promoter methylation of the validated markers increased moderately in early and significantly in advanced-stage melanomas, using early-passage cell strains and snap-frozen tissues (n = 18 and n = 24, respectively) compared with normal melanocytes and nevi (n = 11 and n = 9, respectively). Our approach allows robust identification of methylation markers that can be applied to other studies involving genome-wide promoter methylation. In conclusion, this study represents the first unbiased systematic effort to determine methylation markers in melanoma and revealed several novel genes regulated by promoter methylation that were not described in cancer cells before.
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Affiliation(s)
- Yasuo Koga
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06520-8059, USA
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