1
|
Sapozhnikov DM, Szyf M. Increasing Specificity of Targeted DNA Methylation Editing by Non-Enzymatic CRISPR/dCas9-Based Steric Hindrance. Biomedicines 2023; 11:biomedicines11051238. [PMID: 37238909 DOI: 10.3390/biomedicines11051238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/28/2023] Open
Abstract
As advances in genome engineering inch the technology towards wider clinical use-slowed by technical and ethical hurdles-a newer offshoot, termed "epigenome engineering", offers the ability to correct disease-causing changes in the DNA without changing its sequence and, thus, without some of the unfavorable correlates of doing so. In this review, we note some of the shortcomings of epigenetic editing technology-specifically the risks involved in the introduction of epigenetic enzymes-and highlight an alternative epigenetic editing strategy using physical occlusion to modify epigenetic marks at target sites without a requirement for any epigenetic enzyme. This may prove to be a safer alternative for more specific epigenetic editing.
Collapse
Affiliation(s)
- Daniel M Sapozhnikov
- Department of Pharmacology and Therapeutics, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Moshe Szyf
- Department of Pharmacology and Therapeutics, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3G 1Y6, Canada
| |
Collapse
|
2
|
The methyltransferase domain of DNMT1 is an essential domain in acute myeloid leukemia independent of DNMT3A mutation. Commun Biol 2022; 5:1174. [PMID: 36329185 PMCID: PMC9633652 DOI: 10.1038/s42003-022-04139-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 10/20/2022] [Indexed: 11/06/2022] Open
Abstract
Aberrant DNA methylation patterns are a prominent feature of cancer. Methylation of DNA is mediated by the DNA methyltransferase (DNMT) protein family, which regulates de novo (DNMT3A and DNMT3B) and maintenance (DNMT1) methylation. Mutations in DNMT3A are observed in approximately 22% of acute myeloid leukemia (AML). We hypothesized that DNMT1 or DNMT3B could function as a synthetic lethal therapeutic strategy for DNMT3A-mutant AML. CRISPR-Cas9 tiling screens were performed to identify functional domains within DNMT1/DNMT3B that exhibited greater dependencies in DNMT3A mutant versus wild-type cell lines. Although increased sensitivity to DNMT1 mutation was observed in some DNMT3A mutant cellular models tested, the subtlety of these results prevents us from basing any conclusions on a synthetic lethal relationship between DNMT1 and DNMT3A. Our data suggests that a therapeutic window for DNMT1 methyltransferase inhibition in DNMT3A-driven AML may exist, but validation in more biologically relevant models is required.
Collapse
|
3
|
Shao X, Le Stunff C, Cheung W, Kwan T, Lathrop M, Pastinen T, Bougnères P. Differentially methylated CpGs in response to growth hormone administration in children with idiopathic short stature. Clin Epigenetics 2022; 14:65. [PMID: 35585611 PMCID: PMC9118695 DOI: 10.1186/s13148-022-01281-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 04/17/2022] [Indexed: 11/17/2022] Open
Abstract
Background Recombinant human growth hormone (rhGH) has shown a great growth-promoting potential in children with idiopathic short stature (ISS). However, the response to rhGH differs across individuals, largely due to genetic and epigenetic heterogeneity. Since epigenetic marks on the methylome can be dynamically influenced by GH, we performed a comprehensive pharmacoepigenomics analysis of DNA methylation changes associated with long-term rhGH administration in children with ISS.
Results We measured DNA methylation profiles before and after GH treatment (with a duration of ~ 18 months in average) on 47 healthy children using customized methylC-seq capture sequencing. Their changes were compared and associated with changes in plasma IGF1 by adjusting sex, age, treatment duration and estimated blood proportions. We observed a considerable inter-individual heterogeneity of DNA methylation changes responding to GH treatment. We identified 267 response-associated differentially methylated cytosines (DMCs) that were enriched in promoter regions, CpG islands and blood cell-type-specific regulatory elements. Furthermore, the genes associated with these DMCs were enriched in the biology process of “cell development,” “neuron differentiation” and “developmental growth,” and in the TGF-beta signaling pathway, PPAR Alpha pathway, endoderm differentiation pathway, adipocytokine signaling pathway as well as PI3K-Akt signaling pathway, and cAMP signaling pathway. Conclusion Our study provides a first insight in DNA methylation changes associated with rhGH administration, which may help understand mechanisms of epigenetic regulation on GH-responsive genes. Supplementary Information The online version contains supplementary material available at 10.1186/s13148-022-01281-z.
Collapse
Affiliation(s)
- Xiaojian Shao
- Digital Technologies Research Center, National Research Council Canada, Ottawa, ON, K1A 0R6, Canada.
| | - Catherine Le Stunff
- UMR INSERM 1195 and Université Paris Saclay, Endocrinologie Pédiatrique, Hôpital Bicêtre, 94276, Le Kremlin-Bicêtre Cedex, France
| | - Warren Cheung
- Genomic Medicine Center, Children's Mercy - Kansas City and Children's Mercy Research Institute, Kansas City, MO, 64108, USA
| | - Tony Kwan
- Department of Human Genetics, McGill University and McGill Genome Center, Montreal, QC, H3A 0G1, Canada
| | - Mark Lathrop
- Department of Human Genetics, McGill University and McGill Genome Center, Montreal, QC, H3A 0G1, Canada
| | - Tomi Pastinen
- Genomic Medicine Center, Children's Mercy - Kansas City and Children's Mercy Research Institute, Kansas City, MO, 64108, USA.
| | - Pierre Bougnères
- UMR INSERM 1195 and Université Paris Saclay, Endocrinologie Pédiatrique, Hôpital Bicêtre, 94276, Le Kremlin-Bicêtre Cedex, France.
| |
Collapse
|
4
|
Switzer RL, Medrano J, Reedel DA, Weiss J. Substituted anthraquinones represent a potential scaffold for DNA methyltransferase 1-specific inhibitors. PLoS One 2019; 14:e0219830. [PMID: 31306451 PMCID: PMC6629088 DOI: 10.1371/journal.pone.0219830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/03/2019] [Indexed: 12/13/2022] Open
Abstract
In humans, the most common epigenetic DNA modification is methylation of the 5-carbon of cytosines, predominantly in CpG dinucleotides. DNA methylation is an important epigenetic mark associated with gene repression. Disruption of the normal DNA methylation pattern is known to play a role in the initiation and progression of many cancers. DNA methyltransferase 1 (DNMT1), the most abundant DNA methyltransferase in humans, is primarily responsible for maintenance of the DNA methylation pattern and is considered an important cancer drug target. Recently, laccaic acid A (LCA), a highly substituted anthraquinone natural product, was identified as a direct, DNA-competitive inhibitor of DNMT1. Here, we have successfully screened a small library of simplified anthraquinone compounds for DNMT1 inhibition. Using an endonuclease-coupled DNA methylation assay, we identified two anthraquinone compounds, each containing an aromatic substituent, that act as direct DNMT1 inhibitors. These simplified anthraquinone compounds retain the DNA-competitive mechanism of action of LCA and exhibit some selectivity for DNMT1 over DNMT3a. The newly identified compounds are at least 40-fold less potent than LCA, but have significantly less complex structures. Collectively, this data indicates that substituted anthraquinone compounds could serve as a novel scaffold for developing DNMT1-specific inhibitors.
Collapse
Affiliation(s)
- Rebecca L. Switzer
- Department of Chemistry, Bucknell University, Lewisburg, Pennsylvania, United States of America
- * E-mail:
| | - Jessica Medrano
- Program in Cell Biology/Biochemistry, Bucknell University, Lewisburg, Pennsylvania, United States of America
| | - David A. Reedel
- Program in Cell Biology/Biochemistry, Bucknell University, Lewisburg, Pennsylvania, United States of America
| | - Jill Weiss
- Program in Cell Biology/Biochemistry, Bucknell University, Lewisburg, Pennsylvania, United States of America
| |
Collapse
|
5
|
Luo Y, Yu L, Yu T, Jiang F, Cai X, Zhao Y, Pan S, Luo C. The association of DNA methyltransferase 1 gene polymorphisms with susceptibility to childhood acute lymphoblastic leukemia. Biomed Pharmacother 2015. [PMID: 26211580 DOI: 10.1016/j.biopha.2015.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND It has been suggested that aberrant DNA methylation is a common epigenetic alteration in malignancies. Genetic variations in DNA methyltransferase 1 gene (DNMT1), which encodes the maintenance methyltransferase, have been demonstrated to be involved in cancer susceptibility. In the present study, we investigated whether genetic polymorphisms in DNMT1 could be associated with risk of childhood acute lymphoblastic leukemia (ALL) in a Chinese population. METHODS We selected seven tagging single-nucleotide polymorphisms (tagSNPs, rs11880388, rs10423341, rs7253062, rs11085721, rs2228611, rs2228612 and rs16999593) in DNMT1 and genotyped these SNPs by using TaqMan method in a case-control study of 377 patients with ALL and 500 healthy controls. The logistic regression was used to assess the genetic associations with occurrence of ALL with adjustment for possible confounders. RESULTS We found that one (rs11085721) of the seven tagSNPs was significantly associated with the risk of ALL. Compared with individuals' with DNMT1 rs11085721 GG genotype, those subjects carrying the rs11085721 GT genotypes were associated with significantly increased risk for ALL (GT vs. GG:OR=1.29, 95% CI=1.10-1.51). Similar association was also observed when combined the individuals with rs11085721 GT and rs11085721 TT genotypes (GT/TT vs. TT:OR=1.29, 95% CI=1.10-1.50). No positive results were observed for the other tagSNPs. CONCLUSIONS Our results suggest that the DNMT1 rs11085721 polymorphism may confer susceptibility to ALL in the Chinese population. The initial findings should be validated by large population-based prospective studies in the future.
Collapse
Affiliation(s)
- Ying Luo
- Department of Laboratory Medicine, the First Affiliated Hospital of Nanjing Medical University, 210029 Nanjing, China; Nanjing Red Cross Blood Center, 210003 Nanjing, China
| | - Luting Yu
- School of Life Science and Technology, China Pharmaceutical University, 210009 Nanjing, China
| | - Tingting Yu
- Department of Developmental Genetics, School of Basic Medical Sciences, Nanjing Medical University, 210029 Nanjing, China
| | - Feixia Jiang
- Department of Laboratory medicine, Nanjing First Hospital, Nanjing Medical University, 210006 Nanjing, China
| | - Xubing Cai
- Nanjing Red Cross Blood Center, 210003 Nanjing, China
| | - Yilun Zhao
- Nanjing Red Cross Blood Center, 210003 Nanjing, China
| | - Shiyang Pan
- Department of Laboratory Medicine, the First Affiliated Hospital of Nanjing Medical University, 210029 Nanjing, China.
| | - Chen Luo
- School of Life Science and Technology, China Pharmaceutical University, 210009 Nanjing, China.
| |
Collapse
|
6
|
Cheishvili D, Boureau L, Szyf M. DNA demethylation and invasive cancer: implications for therapeutics. Br J Pharmacol 2015; 172:2705-15. [PMID: 25134627 DOI: 10.1111/bph.12885] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 08/01/2014] [Accepted: 08/13/2014] [Indexed: 02/06/2023] Open
Abstract
One of the hallmarks of cancer is aberrant DNA methylation, which is associated with abnormal gene expression. Both hypermethylation and silencing of tumour suppressor genes as well as hypomethylation and activation of prometastatic genes are characteristic of cancer cells. As DNA methylation is reversible, DNA methylation inhibitors were tested as anticancer drugs with the idea that such agents would demethylate and reactivate tumour suppressor genes. Two cytosine analogues, 5-azacytidine (Vidaza) and 5-aza-2'-deoxycytidine, were approved by the Food and Drug Administration as antitumour agents in 2004 and 2006 respectively. However, these agents might cause activation of a panel of prometastatic genes in addition to activating tumour suppressor genes, which might lead to increased metastasis. This poses the challenge of how to target tumour suppressor genes and block cancer growth with DNA-demethylating drugs while avoiding the activation of prometastatic genes and precluding the morbidity of cancer metastasis. This paper reviews current progress in using DNA methylation inhibitors in cancer therapy and the potential promise and challenges ahead.
Collapse
Affiliation(s)
- David Cheishvili
- Department of Pharmacology and Therapeutics, McGill University Medical School, Montreal, QC, Canada
| | - Lisa Boureau
- Department of Pharmacology and Therapeutics, McGill University Medical School, Montreal, QC, Canada.,Department of Physiology Medical Sciences, University of Toronto 1 King's College Circle Toronto, ON, Canada
| | - Moshe Szyf
- Department of Pharmacology and Therapeutics, McGill University Medical School, Montreal, QC, Canada.,Sackler Program for Epigenetics and Developmental Psychobiology, McGill University Medical School, Montreal, QC, Canada.,Canadian Institute for Advanced Research, Faculty of Medicine, University of Toronto 1 King's College Circle Toronto, ON, Canada
| |
Collapse
|
7
|
Suppression of TET1-dependent DNA demethylation is essential for KRAS-mediated transformation. Cell Rep 2014; 9:1827-1840. [PMID: 25466250 DOI: 10.1016/j.celrep.2014.10.063] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/23/2014] [Accepted: 10/25/2014] [Indexed: 12/31/2022] Open
Abstract
Hypermethylation-mediated tumor suppressor gene (TSG) silencing is a central epigenetic alteration in RAS-dependent tumorigenesis. Ten-eleven translocation (TET) enzymes can depress DNA methylation by hydroxylation of 5-methylcytosine (5mC) bases to 5-hydroxymethylcytosine (5hmC). Here, we report that suppression of TET1 is required for KRAS-induced DNA hypermethylation and cellular transformation. In distinct nonmalignant cell lines, oncogenic KRAS promotes transformation by inhibiting TET1 expression via the ERK-signaling pathway. This reduces chromatin occupancy of TET1 at TSG promoters, lowers levels of 5hmC, and increases levels of 5mC and 5mC-dependent transcriptional silencing. Restoration of TET1 expression by ERK pathway inhibition or ectopic TET1 reintroduction in KRAS-transformed cells reactivates TSGs and inhibits colony formation. KRAS knockdown increases TET1 expression and diminishes colony-forming ability, whereas KRAS/TET1 double knockdown bypasses the KRAS dependence of KRAS-addicted cancer cells. Thus, suppression of TET1-dependent DNA demethylation is critical for KRAS-mediated transformation.
Collapse
|
8
|
Alvarado S, Fernald RD, Storey KB, Szyf M. The dynamic nature of DNA methylation: a role in response to social and seasonal variation. Integr Comp Biol 2014; 54:68-76. [PMID: 24813708 DOI: 10.1093/icb/icu034] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
An organism's ability to adapt to its environment depends on its ability to regulate and maintain tissue specific, temporal patterns of gene transcription in response to specific environmental cues. Epigenetic mechanisms are responsible for many of the intricacies of a gene's regulation that alter expression patterns without affecting the genetic sequence. In particular, DNA methylation has been shown to have an important role in regulating early development and in some human diseases. Within these domains, DNA methylation has been extensively characterized over the past 60 years, but the discovery of its role in regulating behavioral outcomes has led to renewed interest in its potential roles in animal behavior and phenotypic plasticity. The conservation of DNA methylation across the animal kingdom suggests a possible role in the plasticity of genomic responses to environmental cues in natural environments. Here, we review the historical context for the study of DNA methylation, its function and mechanisms, and provide examples of gene/environment interactions in response to social and seasonal cues. Finally, we discuss useful tools to interrogate and dissect the function of DNA methylation in non-model organisms.
Collapse
Affiliation(s)
- Sebastian Alvarado
- *Stanford University, Gilbert Biology #314, 371 Serra Mall, Palo Alto CA 940305; Carleton University, Steacie Building #507, 1125 Colonel By Ottawa Ontario, K1S5B6; McGill University, McIntyre Medical Building #1309, 3655 Sir William Osler,Montreal, Quebec H3G1Y6
| | - Russell D Fernald
- *Stanford University, Gilbert Biology #314, 371 Serra Mall, Palo Alto CA 940305; Carleton University, Steacie Building #507, 1125 Colonel By Ottawa Ontario, K1S5B6; McGill University, McIntyre Medical Building #1309, 3655 Sir William Osler,Montreal, Quebec H3G1Y6
| | - Kenneth B Storey
- *Stanford University, Gilbert Biology #314, 371 Serra Mall, Palo Alto CA 940305; Carleton University, Steacie Building #507, 1125 Colonel By Ottawa Ontario, K1S5B6; McGill University, McIntyre Medical Building #1309, 3655 Sir William Osler,Montreal, Quebec H3G1Y6
| | - Moshe Szyf
- *Stanford University, Gilbert Biology #314, 371 Serra Mall, Palo Alto CA 940305; Carleton University, Steacie Building #507, 1125 Colonel By Ottawa Ontario, K1S5B6; McGill University, McIntyre Medical Building #1309, 3655 Sir William Osler,Montreal, Quebec H3G1Y6*Stanford University, Gilbert Biology #314, 371 Serra Mall, Palo Alto CA 940305; Carleton University, Steacie Building #507, 1125 Colonel By Ottawa Ontario, K1S5B6; McGill University, McIntyre Medical Building #1309, 3655 Sir William Osler,Montreal, Quebec H3G1Y6
| |
Collapse
|
9
|
Subramaniam D, Thombre R, Dhar A, Anant S. DNA methyltransferases: a novel target for prevention and therapy. Front Oncol 2014; 4:80. [PMID: 24822169 PMCID: PMC4013461 DOI: 10.3389/fonc.2014.00080] [Citation(s) in RCA: 309] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 03/31/2014] [Indexed: 12/14/2022] Open
Abstract
Cancer is the second leading cause of death in US. Despite the emergence of new, targeted agents, and the use of various therapeutic combinations, none of the available treatment options are curative in patients with advanced cancer. Epigenetic alterations are increasingly recognized as valuable targets for the development of cancer therapies. DNA methylation at the 5-position of cytosine, catalyzed by DNA methyltransferases (DNMTs), is the predominant epigenetic modification in mammals. DNMT1, the major enzyme responsible for maintenance of the DNA methylation pattern is located at the replication fork and methylates newly biosynthesized DNA. DNMT2 or TRDMT1, the smallest mammalian DNMT is believed to participate in the recognition of DNA damage, DNA recombination, and mutation repair. It is composed solely of the C-terminal domain, and does not possess the regulatory N-terminal region. The levels of DNMTs, especially those of DNMT3B, DNMT3A, and DNMT3L, are often increased in various cancer tissues and cell lines, which may partially account for the hypermethylation of promoter CpG-rich regions of tumor suppressor genes in a variety of malignancies. Moreover, it has been shown to function in self-renewal and maintenance of colon cancer stem cells and need to be studied in several cancers. Inhibition of DNMTs has demonstrated reduction in tumor formation in part through the increased expression of tumor suppressor genes. Hence, DNMTs can potentially be used as anti-cancer targets. Dietary phytochemicals also inhibit DNMTs and cancer stem cells; this represents a promising approach for the prevention and treatment of many cancers.
Collapse
Affiliation(s)
- Dharmalingam Subramaniam
- Department of Molecular and Integrative Physiology, The University of Kansas Medical Center , Kansas City, KS , USA ; The University of Kansas Cancer Center , Kansas City, KS , USA
| | - Ravi Thombre
- Department of Molecular and Integrative Physiology, The University of Kansas Medical Center , Kansas City, KS , USA
| | - Animesh Dhar
- The University of Kansas Cancer Center , Kansas City, KS , USA ; Department of Cancer Biology, The University of Kansas Medical Center , Kansas City, KS , USA
| | - Shrikant Anant
- Department of Molecular and Integrative Physiology, The University of Kansas Medical Center , Kansas City, KS , USA ; The University of Kansas Cancer Center , Kansas City, KS , USA ; Department of Cancer Biology, The University of Kansas Medical Center , Kansas City, KS , USA
| |
Collapse
|
10
|
Stefanska B, Cheishvili D, Suderman M, Arakelian A, Huang J, Hallett M, Han ZG, Al-Mahtab M, Akbar SMF, Khan WA, Raqib R, Tanvir I, Khan HA, Rabbani SA, Szyf M. Genome-wide study of hypomethylated and induced genes in patients with liver cancer unravels novel anticancer targets. Clin Cancer Res 2014; 20:3118-32. [PMID: 24763612 DOI: 10.1158/1078-0432.ccr-13-0283] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE We utilized whole-genome mapping of promoters that are activated by DNA hypomethylation in hepatocellular carcinoma (HCC) clinical samples to shortlist novel targets for anticancer therapeutics. We provide a proof of principle of this approach by testing six genes short-listed in our screen for their essential role in cancer growth and invasiveness. EXPERIMENTAL DESIGN We used siRNA- or shRNA-mediated depletion to determine whether inhibition of these genes would reduce human tumor xenograft growth in mice as well as cell viability, anchorage-independent growth, invasive capacities, and state of activity of nodal signaling pathways in liver, breast, and bladder cancer cell lines. RESULTS Depletion of EXOSC4, RNMT, SENP6, WBSCR22, RASAL2, and NENF effectively and specifically inhibits cancer cell growth and cell invasive capacities in different types of cancer, but, remarkably, there is no effect on normal cell growth, suggesting a ubiquitous causal role for these genes in driving cancer growth and metastasis. Depletion of RASAL2 and NENF in vitro reduces their growth as explants in vivo in mice. RASAL2 and NENF depletion interferes with AKT, WNT, and MAPK signaling pathways as well as regulation of epigenetic proteins that were previously demonstrated to drive cancer growth and metastasis. CONCLUSION Our results prove that genes that are hypomethylated and induced in tumors are candidate targets for anticancer therapeutics in multiple cancer cell types. Because these genes are particularly activated in cancer, they constitute a group of targets for specific pharmacologic inhibitors of cancer and cancer metastasis. Clin Cancer Res; 20(12); 3118-32. ©2014 AACR.
Collapse
Affiliation(s)
- Barbara Stefanska
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, PakistanAuthors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - David Cheishvili
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Matthew Suderman
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Ani Arakelian
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Jian Huang
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Michael Hallett
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Ze-Guang Han
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Mamun Al-Mahtab
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Sheikh Mohammad Fazle Akbar
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Wasif Ali Khan
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Rubhana Raqib
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Imrana Tanvir
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Haseeb Ahmed Khan
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Shafaat A Rabbani
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| | - Moshe Szyf
- Authors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, PakistanAuthors' Affiliations: Departments of Pharmacology and Therapeutics and Medicine, McGill University Health Centre, Montreal; McGill Centre for Bioinformatics; and Sackler program for Psychobiology and Epigenetics at McGill University, Montreal, Quebec, Canada; Department of Nutrition Science, Purdue University, West Lafayette, Indiana; Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China; Department of Hepatology, Bangabandhu Sheikh Mujib Medical University; International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), Dhaka, Dhaka District, Bangladesh; Department of Medical Sciences, Toshiba General Hospital, Tokyo, Kanto, Japan; and Department of Pathology, Fatima Memorial Hospital College of Medicine and Dentistry Lahore, Pakistan
| |
Collapse
|
11
|
Fagan RL, Wu M, Chédin F, Brenner C. An ultrasensitive high throughput screen for DNA methyltransferase 1-targeted molecular probes. PLoS One 2013; 8:e78752. [PMID: 24236046 PMCID: PMC3827244 DOI: 10.1371/journal.pone.0078752] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/20/2013] [Indexed: 12/20/2022] Open
Abstract
DNA methyltransferase 1 (DNMT1) is the enzyme most responsible for epigenetic modification of human DNA and the intended target of approved cancer drugs such as 5-aza-cytidine and 5-aza-2'-deoxycytidine. 5-aza nucleosides have complex mechanisms of action that require incorporation into DNA, and covalent trapping and proteolysis of DNMT isozymes. Direct DNMT inhibitors are needed to refine understanding of the role of specific DNMT isozymes in cancer etiology and, potentially, to improve cancer prevention and treatment. Here, we developed a high throughput pipeline for identification of direct DNMT1 inhibitors. The components of this screen include an activated form of DNMT1, a restriction enzyme-coupled fluorigenic assay performed in 384 well plates with a z-factor of 0.66, a counter screen against the restriction enzyme, a screen to eliminate DNA intercalators, and a differential scanning fluorimetry assay to validate direct binders. Using the Microsource Spectrum collection of 2320 compounds, this screen identified nine compounds with dose responses ranging from 300 nM to 11 µM, representing at least two different pharmacophores with DNMT1 inhibitory activity. Seven of nine inhibitors identified exhibited two to four-fold selectivity for DNMT1 versus DNMT3A.
Collapse
Affiliation(s)
- Rebecca L. Fagan
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Meng Wu
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Frédéric Chédin
- Department of Molecular and Cellular Biology and Genome Center, University of California Davis, Davis, California, United States of America
| | - Charles Brenner
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
| |
Collapse
|
12
|
Fagan RL, Cryderman DE, Kopelovich L, Wallrath LL, Brenner C. Laccaic acid A is a direct, DNA-competitive inhibitor of DNA methyltransferase 1. J Biol Chem 2013; 288:23858-67. [PMID: 23839987 DOI: 10.1074/jbc.m113.480517] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Methylation of cytosines in CpG dinucleotides is the predominant epigenetic mark on vertebrate DNA. DNA methylation is associated with transcriptional repression. The pattern of DNA methylation changes during development and with disease. Human DNA methyltransferase 1 (Dnmt1), a 1616-amino acid multidomain enzyme, is essential for maintenance of DNA methylation in proliferating cells and is considered an important cancer drug target. Using a fluorogenic, endonuclease-coupled DNA methylation assay with an activated form of Dnmt1 engineered to lack the replication foci targeting sequence domain, we discovered that laccaic acid A (LCA), a highly substituted anthraquinone natural product, is a direct inhibitor with a 310 nm Ki. LCA is competitive with the DNA substrate in in vitro methylation assays and alters the expression of methylated genes in MCF-7 breast cancer cells synergistically with 5-aza-2'-deoxycytidine. LCA represents a novel class of Dnmt-targeted molecular probes, with biochemical properties that allow it to distinguish between non DNA-bound and DNA-bound Dnmt1.
Collapse
Affiliation(s)
- Rebecca L Fagan
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | | | | | | | | |
Collapse
|
13
|
Abstract
Asthma is a complex genetic disease, which arises from the interaction of multiple genes and environmental stimuli. These influences are important to asthma pathogenesis. These can be mechanically explained by the Epigenetic phenomenon, which consists of the chromatin and its modifications, as well as a covalent modification of cytosines residing at the dinucleotide sequence CG in DNA by methylation. This reaction is catalyzed by a family of DNA methyltransferase enzyme (DNMTs). DNMT1 is one of them which maintained the methylation status during replication and also critical for the development, differentiation and regulation of Th1 and Th2 cells. Therefore we studied the DNMT1 mRNA expression profiling as well as CpG methylation status in promoter region. For these studies we developed asthma mouse model, and used Flow cytometer, qRT(2)-PCR, Methylation specific PCR, bisulfate conversion and BiQ analyzer. We found that DNMT1 expression level was low in all the tissues (lung, trachea and BALF cells) of asthmatic in comparison to normal mice. This was due to the methylation of regulatory sites of DNMT1 promoter region at cytosine residue. As the incidence of asthma is increasing globally and in world, this study assumes greater significance in designing and developing therapeutic means.
Collapse
|
14
|
Thomas X. DNA methyltransferase inhibitors in acute myeloid leukemia: discovery, design and first therapeutic experiences. Expert Opin Drug Discov 2012; 7:1039-51. [PMID: 22950862 DOI: 10.1517/17460441.2012.722618] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION DNA methylation is an epigenetic change mediated by DNA methyltranferases (DNMTs), which are promising epigenetic targets for the treatment of acute myeloid leukemia (AML). This is evidenced by the two DNMT inhibitors (azacitidine and decitabine) approved by the Food and Drug Administration of the United States for the treatment of high-risk myelodysplastic syndromes and the first clinical data available in AML. AREAS COVERED This paper reviews data from the international literature regarding the design, sites of impact and pharmacodynamic characteristics of DNMT inhibitors, and their first clinical experiences in AML. EXPERT OPINION The strongest advances in epigenetic therapy have been in the treatment of AML. There are now an increasing number of DNMT inhibitors. These agents may be potentially administered at different times of leukemia therapy: before or instead of chemotherapy, as maintenance therapy, prior to allogeneic stem cell transplant (SCT) or after relapse following SCT.
Collapse
Affiliation(s)
- Xavier Thomas
- Hospices Civils de Lyon, Centre Hospitalier Lyon-Sud, Service d'Hématologie Clinique, Pierre Bénite, France.
| |
Collapse
|
15
|
Role of epigenetics in cancer initiation and progression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 720:91-104. [PMID: 21901621 DOI: 10.1007/978-1-4614-0254-1_8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The epigenome which comprises DNA methylation, histone modifications, chromatin structures and non-coding RNAs controls gene expression patterns. In cancer cells, there are aberrant changes in the epigenome. The question in cancer epigenetics is that whether these changes are the cause of cell transformation, or rather the consequence of it. We will discuss the epigenetic phenomenon in cancer, as well as the recent interests in the epigenetic reprogramming events, and their implications in the cancer stem cell theory. We will also look at the progression of cancers as they become more aggressive, with focus on the role of epigenetics in tumor metastases exemplified with the urokinase plasminogen activator (uPA) system. Last but not least, with therapeutics intervention in mind, we will highlight the importance of balance in the design of epigenetic based anti-cancer therapeutic strategies.
Collapse
|
16
|
Amatori S, Bagaloni I, Donati B, Fanelli M. DNA demethylating antineoplastic strategies: a comparative point of view. Genes Cancer 2011; 1:197-209. [PMID: 21779447 DOI: 10.1177/1947601910365081] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Despite the involvement of genetic alterations in neoplastic cell transformation, it is increasingly evident that abnormal epigenetic patterns, such as those affecting DNA methylation and histone posttranslational modifications (PTMs), play an essential role in the early stages of tumor development. This finding, together with the evidence that epigenetic changes are reversible, enabled the development of new antineoplastic therapeutic approaches known as epigenetic therapies. Epigenetic modifications are involved in the control of gene expression, and their aberrant distribution is thought to participate in neoplastic transformation by causing the deregulation of crucial cellular pathways. Epigenetic drugs are able to revert the defective gene expression profile of cancer cells and, consequently, reestablish normal molecular pathways. Considering the emerging interest in epigenetic therapeutics, this review focuses on the approaches affecting DNA methylation, evaluates novel strategies and those already approved for clinical use, and compares their therapeutic potential.
Collapse
Affiliation(s)
- Stefano Amatori
- Molecular Pathology and Oncology Lab. "PaoLa," Department of Biomolecular Sciences, University of Urbino "Carlo Bo," Fano, Italy
| | | | | | | |
Collapse
|
17
|
Cheng JC, Auersperg N, Leung PCK. Inhibition of p53 represses E-cadherin expression by increasing DNA methyltransferase-1 and promoter methylation in serous borderline ovarian tumor cells. Oncogene 2011; 30:3930-42. [PMID: 21478913 DOI: 10.1038/onc.2011.117] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 03/08/2011] [Accepted: 03/08/2011] [Indexed: 12/31/2022]
Abstract
The mechanisms underlying the progression of noninvasive serous borderline ovarian tumors (SBOT) to low-grade invasive carcinomas are poorly understood. We recently showed that inhibition of p53 induces SBOT invasion by activating the PI3K/Akt pathway and transcriptionally repressing E-cadherin. In human cancers, aberrant DNA methylation is a common phenomenon, and it is thought to be involved in the progression from noninvasive to invasive ovarian carcinomas. In this study, we tested the hypothesis that inhibition of p53 downregulates E-cadherin by regulating the methylation of its promoter in SBOT cells. Here, we show that DNA methyltransferase-1 (DNMT1), but not DNMT3a or DNMT3b, was increased in SV40 LT-infected SBOT4 cells, SBOT4-LT and the low-grade invasive serous ovarian carcinoma-derived cell line MPSC1. Treatment with 5-Aza-dC, a DNMT1 inhibitor, restored E-cadherin promoter methylation and expression, and inhibited cell invasion in both invasive SBOT4-LT and MPSC1 cells. Moreover, knockdown of endogenous p53 using siRNA in SBOT3.1 cells induced DNMT1 expression and led to an increase in E-cadherin promoter methylation. Additionally, activation of the PI3K/Akt pathway is required for p53 inhibition-induced DNMT1 expression. The increase in DNMT1 was associated with the inhibition of p53-induced downregulation of E-cadherin and cell invasion. Our findings show an important role for p53 in the progression of SBOT to an invasive carcinoma, and suggest that downregulation of E-cadherin by DNMT1-mediated promoter methylation contributes to this process.
Collapse
Affiliation(s)
- J-C Cheng
- Department of Obstetrics and Gynecology, Child & Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | |
Collapse
|
18
|
Frenette C, Gish RG. Hepatocellular carcinoma: molecular and genomic guideline for the clinician. Clin Liver Dis 2011; 15:307-21, vii-x. [PMID: 21689615 DOI: 10.1016/j.cld.2011.03.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Understanding of the genetic changes and molecular signaling pathways that are active in hepatocellular carcinoma has improved substantially over the last decade. As more information becomes available, it is clear that the prognostication of hepatocellular carcinoma will soon include molecular and genomic "fingerprints" that are unique to each cancer, which will allow more personalized treatment plans for patients as more targeted therapies become available. This article discusses the molecular and genomic changes that are important in hepatocellular carcinoma in order for clinicians to understand the current and forthcoming treatment options for patients with liver cancer.
Collapse
Affiliation(s)
- Catherine Frenette
- The Methodist Center for Liver Disease, J.C. Walter Transplant Center, Department of Medicine, The Methodist Hospital, 6550 Fannin Street, SM 1001, Houston, TX 77098, USA.
| | | |
Collapse
|
19
|
Oghamian S, Sodir NM, Bashir MU, Shen H, Cullins AE, Carroll CA, Kundu P, Shibata D, Laird PW. Reduction of pancreatic acinar cell tumor multiplicity in Dnmt1 hypomorphic mice. Carcinogenesis 2011; 32:829-35. [PMID: 21362628 DOI: 10.1093/carcin/bgr039] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In human pancreatic cancers, promoter CpG island hypermethylation is observed in both benign and malignant tumors. It is thought that silencing of key growth-controlling genes by promoter hypermethylation may play a role in pancreatic oncogenesis. We have shown previously that sufficient levels of DNA methyltransferase (Dnmt) 1 expression are required for the development of murine intestinal tumors. Here, we report the results of a large-scale triple cross (progeny n = 761) between Apc(Min/+), Trp53(-/-) and Dnmt1 hypomorphic mice to investigate the role of Dnmt levels in the Apc(Min/+), Trp53(-/-) mouse models of acinar cell pancreatic cancer. Mutations of both APC and TP53 are observed in human pancreatic cancer. We found that tumor burden, but not tumor size, is significantly reduced with decreasing Dnmt1 levels, suggesting that DNA methylation is involved in pancreatic tumorigenesis in this mouse model. Detailed analyses showed that the reduction in tumor burden is the result of a decrease in both early- and late-stage lesions. We observed decreased levels of DNA methylation at candidate genes in the normal pancreas of Dnmt1 hypomorphic mice. Some of these genes showed increased methylation associated with tumorigenesis, suggesting that the tumor-suppressive effects of Dnmt1 hypomorphic alleles may be mediated in part through reduced promoter hypermethylation. Our work is the first in vivo study to show the effects of reduced Dnmt levels on pancreatic tumor development.
Collapse
Affiliation(s)
- Shirley Oghamian
- Department of Surgery, USC/Norris Comprehensive Cancer Center, Keck School of Medicine, Los Angeles, CA 90089-9176, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Zeranol down-regulates p53 expression in primary cultured human breast cancer epithelial cells through epigenetic modification. Int J Mol Sci 2011; 12:1519-32. [PMID: 21673905 PMCID: PMC3111616 DOI: 10.3390/ijms12031519] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 01/30/2011] [Accepted: 02/12/2011] [Indexed: 01/10/2023] Open
Abstract
Epidemiological studies have suggested that there are many risk factors associated with breast cancer. Silencing tumor suppressor genes through epigenetic alterations play critical roles in breast cancer initiation, promotion and progression. As a growth promoter, Zeranol (Z) has been approved by the FDA and is widely used to enhance the growth of beef cattle in the United States. However, the safety of Z use as a growth promoter is still under debate. In order to provide more evidence to clarify this critical health issue, the current study investigated the effect of Z on the proliferation of primary cultured human normal and cancerous breast epithelial cells (PCHNBECs and PCHBCECs, respectively) isolated from the same patient using MTS assay, RT-PCR and Western blot analysis. We also conducted an investigation regarding the mechanisms that might be involved. Our results show that Z is more potent to stimulate PCHBCEC growth than PCHNBEC growth. The stimulatory effects of Z on PCHBCECs and PCHBCECs may be mediated by its down-regulating expression of the tumor suppressor gene p53 at the mRNA and protein levels. Further investigation showed that the expression of DNA methylatransferase 1 mRNA and protein levels is up-regulated by treatment with Z in PCHBCECs as compared to PCHNBECs, which suggests a role of Z in epigenetic modification involved in the regulation of p53 gene expression in PCHBCECs. Our experimental results imply the potentially adverse health effect of Z in breast cancer development. Further study is continuing in our laboratory.
Collapse
|
21
|
Chik F, Szyf M. Effects of specific DNMT gene depletion on cancer cell transformation and breast cancer cell invasion; toward selective DNMT inhibitors. Carcinogenesis 2011; 32:224-32. [PMID: 20980350 DOI: 10.1093/carcin/bgq221] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
A hallmark of cancer is aberrant DNA methylation, consisting of global hypomethylation and regional hypermethylation of tumor suppressor genes. DNA methyltransferase inhibitors have been recognized as promising candidate anticancer drugs. Drug development has focused on DNA methylation inhibitors with the goal of activating tumor suppressor genes silenced by DNA methylation. 5-azacytidine (5-AC; Vidaza), a global DNA methyltransferase inhibitor, was Food and Drug Administration approved to treat myelodysplastic syndromes and is clinically tested for solid tumors. In this paper, it was demonstrated that 5'-aza-2'-deoxycytidine (5-azaCdR) activated both silenced tumor suppressor genes and pro-metastatic genes by demethylation, raising the concern that it would promote metastasis. 5-AzaCdR treatment increased the invasiveness of non-invasive breast cancer cell lines MCF-7 cells and ZR-75-1 and dramatically induced pro-metastatic genes; Urokinase plasminogen activator (uPA), matrix metalloproteinase 2 (MMP2), metastasis-associated gene (H-MTS1; S100A4) and C-X-C chemokine receptor 4 (CXCR4). The hypothesis that the blocking of cellular transformation activity of DNA methyltransferase inhibitor could be separated from the pro-metastatic activity was tested using short interfering RNA (siRNA) targeted to the different DNA methyltransferase (DNMT) genes. Although depletion of DNMT1 had the strongest effect on colony growth suppression in cellular transformation assays, it did not result in demethylation and activation of uPA, S100A4, MMP2 and CXCR4 in MCF-7 cells. Depletion of DNMT1 did not induce cellular invasion in MCF-7 and ZR-75-1 non-invasive breast cancer cell lines. These data have implications on the design of new DNA methyltransferase inhibitor and on the proper utilization of current inhibitors.
Collapse
Affiliation(s)
- Flora Chik
- Department of Pharmacology and Therapeutics, McGill University Medical School, Montreal, Quebec, Canada
| | | |
Collapse
|
22
|
|
23
|
Szyf M. The role of DNA hypermethylation and demethylation in cancer and cancer therapy. ACTA ACUST UNITED AC 2010; 15:72-5. [PMID: 18454186 PMCID: PMC2365485 DOI: 10.3747/co.v15i2.210] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- M Szyf
- McGill University, Department of Pharmacology and Therapeutics,McIntyre Medical Building, Montreal, Quebec, Canada.
| |
Collapse
|
24
|
Abstract
Evidence is emerging that several diseases and behavioral pathologies result from defects in gene function. The best-studied example is cancer, but other diseases such as autoimmune disease, asthma, type 2 diabetes, metabolic disorders, and autism display aberrant gene expression. Gene function may be altered by either a change in the sequence of the DNA or a change in epigenetic programming of a gene in the absence of a sequence change. With epigenetic drugs, it is possible to reverse aberrant gene expression profiles associated with different disease states. Several epigenetic drugs targeting DNA methylation and histone deacetylation enzymes have been tested in clinical trials. Understanding the epigenetic machinery and the differential roles of its components in specific disease states is essential for developing targeted epigenetic therapy.
Collapse
Affiliation(s)
- Moshe Szyf
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec H3G 1Y6, Canada.
| |
Collapse
|
25
|
Pharmacological inhibition of DNA methylation induces proinvasive and prometastatic genes in vitro and in vivo. Neoplasia 2008; 10:266-78. [PMID: 18320071 DOI: 10.1593/neo.07947] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 01/06/2008] [Accepted: 01/07/2008] [Indexed: 01/03/2023] Open
Abstract
The mechanism of action of DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-aza-CdR), a potential anticancer agent is believed to be activated by the demethylation of tumor suppressor genes. We tested here the hypothesis that demethylating agents also demethylate and activate genes involved in invasion and metastasis and therefore might increase the risk of developing tumor metastasis. The effect of 5-aza-CdR on noninvasive human breast cancer cells MCF-7 and ZR-75-1 was evaluated by cell proliferation, invasion, and migration assay. The ability of 5-aza-CdR to activate a panel of silenced prometastatic and tumor suppressor genes was evaluated using reverse transcription-polymerase chain reaction and bisulfite DNA sequence analysis in vitro and for change in tumor growth and gene expression in vivo. Treatment of MCF-7 and ZR-75-1 with 5-aza-CdR diminished cell proliferation, induced tumor suppressor RASSF1A, and altered cell cycle kinetics' G(2)/M-phase cell cycle arrest. While these effects of 5-aza-CdR slowed the growth of tumors in nude mice, it also induced a battery of prometastatic genes, namely, uPA, CXCR4, HEPARANASE, SYNUCLEIN gamma, and transforming growth factor-beta (TGF-beta), by demethylation of their promoters. These results draw attention to the critical role of demethylation as a potential mechanism that can promote the development and progression of tumor metastasis after demethylation therapy as an anticancer treatment.
Collapse
|
26
|
Szyf M. DNA demethylation and cancer metastasis: therapeutic implications. Expert Opin Drug Discov 2008; 3:519-31. [DOI: 10.1517/17460441.3.5.519] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
27
|
Kirk Field A, Goodchild J. Section Review: Biologicals & Immunologicals: Antisense oligonucleotides: Rational drug design for genetic pharmacology. Expert Opin Investig Drugs 2008. [DOI: 10.1517/13543784.4.9.799] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
28
|
DNA methyltransferase 1 knockdown induces silenced CDH1 gene reexpression by demethylation of methylated CpG in hepatocellular carcinoma cell line SMMC-7721. Eur J Gastroenterol Hepatol 2007; 19:952-61. [PMID: 18049164 DOI: 10.1097/meg.0b013e3282c3a89e] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
BACKGROUND Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related mortality in the world; however, the molecular mechanisms leading to hepatocyte transformation, especially in epigenetic mechanisms (such as DNA methylation) are still poorly understood. DNA methyltransferase 1 (DNMT1) is the predominant maintenance methyltransferase gene required to maintain DNA methylation patterns in mammalian cells. AIM AND METHODS To explore the role of DNMT1 in the regulation of expression of tumor-related genes in human HCC cells via DNA methylation of the regulatory CpG islands, we stably transfected expression constructs containing small interfering RNA (siRNA) of DNMT1 into the human HCC cell line, SMMC-7721. RESULTS RNA interference knocked down specific DNMT1 protein expression, resulting in the demethylated promoter of CDH1 and the reexpression of CDH1 in 7721-pMT1. By contrast, promoter methylation and lack of gene expression were maintained when the cell lines had control constructs. Knock down of DNMT1 expression by siRNA induced the promoter of CDH1 demethylation and upregulated CDH1 transcription. High-density oligonucleotide gene expression microarrays were used to examine the effects of DNMT1 knock down on human HCC cells (SMMC-7721); these showed that a number of genes were induced in the DNMT1 knock down cell lines, including some important tumor-related genes such as PDCD4, DCN and PTGES except CDH1. Only approximately 78% of the induced genes have CpG islands within their 5' regions, suggesting that certain genes activated by DNMT1 siRNA might not have resulted from the direct inhibition of promoter methylation. CONCLUSION In hepatocellular carcinoma, DNMT1 is necessary to maintain the methylation of CpG islands in certain tumor-related genes.
Collapse
|
29
|
Torrisani J, Unterberger A, Tendulkar SR, Shikimi K, Szyf M. AUF1 cell cycle variations define genomic DNA methylation by regulation of DNMT1 mRNA stability. Mol Cell Biol 2007; 27:395-410. [PMID: 17030625 PMCID: PMC1800664 DOI: 10.1128/mcb.01236-06] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 07/28/2006] [Accepted: 09/22/2006] [Indexed: 01/26/2023] Open
Abstract
DNA methylation is a major determinant of epigenetic inheritance. DNA methyltransferase 1 (DNMT1) is the enzyme responsible for the maintenance of DNA methylation patterns during cell division, and deregulated expression of DNMT1 leads to cellular transformation. We show herein that AU-rich element/poly(U)-binding/degradation factor 1 (AUF1)/heterogeneous nuclear ribonucleoprotein D interacts with an AU-rich conserved element in the 3' untranslated region of the DNMT1 mRNA and targets it for destabilization by the exosome. AUF1 protein levels are regulated by the cell cycle by the proteasome, resulting in cell cycle-specific destabilization of DNMT1 mRNA. AUF1 knock down leads to increased DNMT1 expression and modifications of cell cycle kinetics, increased DNA methyltransferase activity, and genome hypermethylation. Concurrent AUF1 and DNMT1 knock down abolishes this effect, suggesting that the effects of AUF1 knock down on the cell cycle are mediated at least in part by DNMT1. In this study, we demonstrate a link between AUF1, the RNA degradation machinery, and maintenance of the epigenetic integrity of the cell.
Collapse
Affiliation(s)
- Jerome Torrisani
- Department of Pharmacology and Therapeutics, McGill University, 3655 Sir William Osler Promenade, Montreal, Quebec H3G 1Y6, Canada
| | | | | | | | | |
Collapse
|
30
|
Shukeir N, Pakneshan P, Chen G, Szyf M, Rabbani SA. Alteration of the methylation status of tumor-promoting genes decreases prostate cancer cell invasiveness and tumorigenesis in vitro and in vivo. Cancer Res 2006; 66:9202-10. [PMID: 16982764 DOI: 10.1158/0008-5472.can-06-1954] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We tested the hypothesis that cell invasiveness and tumorigenesis are driven by hypomethylation of genes involved in tumor progression. Highly invasive human prostate cancer cells PC-3 were treated with either the methyl donor S-adenosylmethionine (SAM) or methyl DNA-binding domain protein 2 antisense oligonucleotide (MBD2-AS). Both treatments resulted in a dose- and time-dependent inhibition of key genes, such as urokinase-type plasminogen activator (uPA), matrix metalloproteinase-2 (MMP-2), and vascular endothelial growth factor expression to decrease tumor cell invasion in vitro. No change in the levels of expression of genes already known to be methylated in late-stage prostate cancer cells, such as glutathione S-transferase P1 and androgen receptor, was seen. Inoculation of PC-3 cells pretreated with SAM and MBD2-AS into the flank of male BALB/c nu/nu mice resulted in the development of tumors of significantly smaller volume compared with animals inoculated with PC-3 cells treated with vehicle alone or MBD2 scrambled oligonucleotide. Immunohistochemical analysis of tumors showed the ability of SAM and MBD2-AS to significantly decrease tumoral uPA and MMP-2 expression along with levels of angiogenesis and survival pathway signaling molecules. Bisulfite sequencing analysis of tumoral genomic DNA showed that inhibition of both uPA and MMP-2 expression was due to methylation of their 5' regulatory region. These studies support the hypothesis that DNA hypomethylation controls the activation of multiple tumor-promoting genes and provide valuable insight into developing novel therapeutic strategies against this common disease, which target the demethylation machinery.
Collapse
Affiliation(s)
- Nicholas Shukeir
- Department of Medicine, McGill University, Montreal, Quebec, Canada
| | | | | | | | | |
Collapse
|
31
|
Unterberger A, Andrews SD, Weaver ICG, Szyf M. DNA methyltransferase 1 knockdown activates a replication stress checkpoint. Mol Cell Biol 2006; 26:7575-86. [PMID: 17015478 PMCID: PMC1636877 DOI: 10.1128/mcb.01887-05] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
DNA methyltransferase 1 (DNMT1) is an important component of the epigenetic machinery and is responsible for copying DNA methylation patterns during cell division. Coordination of DNA methylation and DNA replication is critical for maintaining epigenetic programming. Knockdown of DNMT1 leads to inhibition of DNA replication, but the mechanism has been unclear. Here we show that depletion of DNMT1 with either antisense or small interfering RNA (siRNA) specific to DNMT1 activates a cascade of genotoxic stress checkpoint proteins, resulting in phosphorylation of checkpoint kinases 1 and 2 (Chk1 and -2), gammaH2AX focus formation, and cell division control protein 25a (CDC25a) degradation, in an ataxia telangiectasia mutated-Rad3-related (ATR)-dependent manner. siRNA knockdown of ATR blocks the response to DNMT1 depletion; DNA synthesis continues in the absence of DNMT1, resulting in global hypomethylation. Similarly, the response to DNMT1 knockdown is significantly attenuated in human mutant ATR fibroblast cells from a Seckel syndrome patient. This response is sensitive to DNMT1 depletion, independent of the catalytic domain of DNMT1, as indicated by abolition of the response with ectopic expression of either DNMT1 or DNMT1 with the catalytic domain deleted. There is no response to short-term treatment with 5-aza-deoxycytidine (5-aza-CdR), which causes demethylation by trapping DNMT1 in 5-aza-CdR-containing DNA but does not cause disappearance of DNMT1 from the nucleus. Our data are consistent with the hypothesis that removal of DNMT1 from replication forks is the trigger for this response.
Collapse
Affiliation(s)
- Alexander Unterberger
- Department of Pharmacology and Therapeutics, McGill University, 3655 Sir William Osler Promenade, Montréal, Québec, Canada H3G 1Y6
| | | | | | | |
Collapse
|
32
|
McCabe MT, Low JA, Imperiale MJ, Day ML. Human polyomavirus BKV transcriptionally activates DNA methyltransferase 1 through the pRb/E2F pathway. Oncogene 2006; 25:2727-35. [PMID: 16547506 DOI: 10.1038/sj.onc.1209266] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many DNA tumor virus oncogenes are capable of activating and highjacking the host cell's DNA replication machinery for its own reproduction purposes through targeting and inactivation of the retinoblastoma pocket protein family. Pocket proteins function to regulate cell cycle progression and DNA synthesis through inhibitory interactions with the E2F transcription factors. The interaction of viral oncogenes with the pocket proteins is crucial for their transforming activity. We recently demonstrated that the DNA methyltransferase 1 (DNMT1) gene is an E2F target gene that is transcriptionally activated in cells lacking the retinoblastoma gene (Rb-/-). Overexpression of DNMT1 is implicated in tumor suppressor gene hypermethylation which is associated with tumorigenesis. Given that viral oncogenes potently stimulate E2F activity, we hypothesized that viral infection might activate DNMT1 and thereby promote transformation. Herein, we demonstrate that DNMT1 is strongly activated by the human polyomavirus BKV large T antigen (TAg) and adenovirus E1a. Viral oncogene mutants incapable of binding the pocket proteins are ineffective at activating DNMT1 compared to their wild-type counterparts. Additionally, mutation of the E2F sites within the DNMT1 promoters dramatically abrogates transcriptional activation. These data suggest that viral induction of DNMT1 through modulation of the pRB/E2F pathway may be involved in viral transformation.
Collapse
MESH Headings
- Adenocarcinoma/genetics
- Adenocarcinoma/metabolism
- Adenocarcinoma/virology
- Adenovirus E1A Proteins/metabolism
- Animals
- Antigens, Polyomavirus Transforming/genetics
- Antigens, Polyomavirus Transforming/metabolism
- BK Virus/physiology
- Cell Transformation, Viral
- Cells, Cultured
- DNA (Cytosine-5-)-Methyltransferase 1
- DNA (Cytosine-5-)-Methyltransferases/genetics
- DNA (Cytosine-5-)-Methyltransferases/metabolism
- E2F Transcription Factors/genetics
- E2F Transcription Factors/metabolism
- Embryo, Mammalian/cytology
- Embryo, Mammalian/metabolism
- Enzyme Activation
- Fibroblasts/cytology
- Fibroblasts/metabolism
- Humans
- Luciferases
- Male
- Mice
- Mice, Knockout
- Mutation
- NIH 3T3 Cells/metabolism
- NIH 3T3 Cells/virology
- Polyomavirus Infections/immunology
- Polyomavirus Infections/virology
- Promoter Regions, Genetic/genetics
- Prostatic Neoplasms/genetics
- Prostatic Neoplasms/metabolism
- Prostatic Neoplasms/virology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Retinoblastoma Protein/genetics
- Retinoblastoma Protein/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Transcription, Genetic
- Transcriptional Activation
Collapse
Affiliation(s)
- M T McCabe
- Program in Cellular and Molecular Biology, Department of Urology, University of Michigan, Ann Arbor, MI 48109-0944, USA
| | | | | | | |
Collapse
|
33
|
Abstract
Alterations in chromatin structure resulting from aberrant DNA methylation and perturbations of the histone code profoundly influence gene expression during pulmonary carcinogenesis. Recent studies indicate that DNA demethylating agents and histone deacetylase (HDAC) inhibitors synergistically induce gene expression and apoptosis in cultured lung cancer cells, and prevent lung cancer development in animals following exposure to tobacco carcinogens. Preliminary clinical trials have established proof of principle regarding the use of DNA demethylating agents and HDAC inhibitors for enhancing immunogenicity and apoptosis of lung cancer cells, and have revealed the complexities concerning the mechanisms by which chromatin remodeling agents mediate antitumor effects in vivo. These data support additional investigations pertaining to the epigenetics of lung cancer, and the evaluation of chromatin remodeling agents for the treatment and prevention of this disease.
Collapse
Affiliation(s)
- David S Schrump
- Thoracic Oncology Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892-1201, USA.
| | | |
Collapse
|
34
|
Ehrlich M. The controversial denouement of vertebrate DNA methylation research. BIOCHEMISTRY (MOSCOW) 2005; 70:568-75. [PMID: 15948710 DOI: 10.1007/s10541-005-0150-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The study of the biological role of DNA methylation in vertebrates has involved considerable controversy. Research in this area has proceeded well despite the complexity of the subject and the difficulties in establishing biological roles, some of which are summarized in this review. Now there is justifiably much more interest in DNA methylation than previously, and many more laboratories are engaged in this research. The results of numerous studies indicate that some tissue-specific differences in vertebrate DNA methylation help maintain patterns of gene expression or are involved in fine-tuning or establishing expression patterns. Therefore, vertebrate DNA methylation cannot just be assigned a role in silencing transposable elements and foreign DNA sequences, as has been suggested. DNA methylation is clearly implicated in modulating X chromosome inactivation and in establishing genetic imprinting. Also, hypermethylation of CpG-rich promoters of tumor suppressor genes in cancer has a critical role in downregulating expression of these genes and thus participating in carcinogenesis. The complex nature of DNA methylation patterns extends to carcinogenesis because global DNA hypomethylation is found in the same cancers displaying hypermethylation elsewhere in the genome. A wide variety of cancers display both DNA hypomethylation and hypermethylation, and either of these types of changes can be significantly associated with tumor progression. These findings and the independence of cancer-linked DNA hypomethylation from cancer-linked hypermethylation strongly implicate DNA hypomethylation, as well as hypermethylation, in promoting carcinogenesis. Furthermore, various DNA demethylation methodologies have been shown to increase the formation of certain types of cancers in animals, and paradoxically, DNA hypermethylation can cause carcinogenesis in other model systems. Therefore, there is a need for caution in the current use of demethylating agents as anti-cancer drugs. Nonetheless, DNA demethylation therapy clearly may be very useful in cases where better alternatives do not exist.
Collapse
Affiliation(s)
- M Ehrlich
- Human Genetics Program SL31, Tulane Medical School, New Orleans, LA 70112, USA.
| |
Collapse
|
35
|
Szyf M. DNA methylation and demethylation as targets for anticancer therapy. BIOCHEMISTRY (MOSCOW) 2005; 70:533-49. [PMID: 15948707 DOI: 10.1007/s10541-005-0147-7] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cancer growth and metastasis require the coordinate change in gene expression of different sets of genes. While genetic alterations can account for some of these changes, it is becoming evident that many of the changes in gene expression observed are caused by epigenetic modifications. The epigenome consists of the chromatin and its modifications, the "histone code" as well as the pattern of distribution of covalent modifications of cytosines residing in the dinucleotide sequence CG by methylation. Although hypermethylation of tumor suppressor genes has attracted a significant amount of attention and inhibitors of DNA methylation were shown to activate methylated tumor suppressor genes and inhibit tumor growth, demethylation of critical genes plays a critical role in cancer as well. This review discusses the emerging role of demethylation in activation of pro-metastatic genes and the potential therapeutic implications of the demethylation machinery in metastasis.
Collapse
Affiliation(s)
- M Szyf
- Department of Pharmacology and Therapeutics, McGill University, Montreal PQ H3G 1Y6, Canada.
| |
Collapse
|
36
|
Abstract
Tumor suppressor gene silencing by DNA hypermethylation contributes to tumorigenesis in many tumor types. This aberrant methylation may be due to increased expression and activity of DNA methyltransferases, which catalyze the transfer of methyl groups from S-adenosylmethionine to cytosines in CpG dinucleotides. Elevated expression of the maintenance DNA methyltransferase, DNA methyltransferase 1 (DNMT-1), has been shown in carcinomas of the colon, lung, liver, and prostate. Based on the nearly ubiquitous alterations of both DNA methylation and the retinoblastoma protein (pRb) pathway found in human cancer, we investigated a potential regulatory pathway linking the two alterations in murine and human prostate epithelial cells. Analysis of DNA methyltransferase levels in Rb-/- murine prostate epithelial cell lines revealed elevated Dnmt-1 levels. Genomic DNA sequence analysis identified conserved E2F consensus binding sites in proximity to the transcription initiation points of murine and human Dnmt-1. Furthermore, the Dnmt-1 promoter was shown to be regulated by the pRb/E2F pathway in murine and human cell lines of epithelial and fibroblast origin. In the absence of pRb, Dnmt-1 transcripts exhibited aberrant cell cycle regulation and Rb-/- cells showed aberrant methylation of the paternally expressed gene 3 (Peg3) tumor suppressor gene. These findings show a link between inactivation of the pRb pathway and induction of DNA hypermethylation of CpG island-containing genes in tumorigenesis.
Collapse
Affiliation(s)
- Michael T McCabe
- Department of Urology, Michigan Urology Center, University of Michigan, Ann Arbor, Michigan 48109-0944, USA
| | | | | |
Collapse
|
37
|
Yuan BZ, Jefferson AM, Popescu NC, Reynolds SH. Aberrant gene expression in human non small cell lung carcinoma cells exposed to demethylating agent 5-aza-2'-deoxycytidine. Neoplasia 2005; 6:412-9. [PMID: 15256063 PMCID: PMC1502114 DOI: 10.1593/neo.03490] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes undergoing genetic or epigenetic alterations and contributing to the development of cancer is critical to our understanding of the molecular mechanisms of carcinogenesis. A new approach in identifying alterations of genes that might be relevant to the process of tumor development was used in this study by examining the gene expression profile in human lung cancer cells exposed to 5-aza-2'-deoxycytidine (5-aza-dC). A cDNA array analysis was carried out on 5-aza-dC-treated and untreated non small cell lung cancer (NSCLC) cell line NCI-H522. Sixteen and 14 genes were upregulated and downregulated, respectively, by 5-aza-dC treatment. Among them, downregulation of tyrosine protein kinase ABL2 (ABL2) gene and upregulation of hint/protein kinase C inhibitor 1 (Hint/PKCI-1), DVL1, TIMP-1, and TRP-1 genes were found in expanded observations in two or three of five 5-aza-dC-treated NSCLC cell lines. Among these genes, we found that cDNA transfer of Hint/PKCI-1 resulted in a significant in vitro growth inhibition in two cell lines exhibiting 5-aza-dC-induced upregulation of Hint/PKCI-1 and significantly reduced in vivo tumorigenicity of one NSCLC cell line. Hint/PKCI-1, which is the only other characterized human histidine triad (HIT) nucleotide-binding protein in addition to tumor-suppressor gene FHIT, might be involved in lung carcinogenesis.
Collapse
Affiliation(s)
- Bao-Zhu Yuan
- Laboratory of Cancer Genetics, Toxicology and Molecular Biology Branch, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV 26505, USA.
| | | | | | | |
Collapse
|
38
|
Cho-Chung YS. Antisense and therapeutic oligonucleotides: toward a gene-targeting cancer clinic. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.10.11.1711] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
39
|
Szyf M, Pakneshan P, Rabbani SA. DNA demethylation and cancer: therapeutic implications. Cancer Lett 2004; 211:133-43. [PMID: 15219937 DOI: 10.1016/j.canlet.2004.04.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Accepted: 04/20/2004] [Indexed: 01/12/2023]
Abstract
The epigenome, which is comprised of chromatin and its associated proteins and the patterns of covalent modification of DNA by methylation, sets up and maintains gene expression programs. A hallmark of cancer is a paradoxical aberration of DNA methylation patterns, a global loss of DNA methylation, that coexists with regional hypermethylation of certain genes. The hypermethylation of tumor-suppressor genes has attracted significant attention recently and DNA methylation inhibitors are being tested as potential anticancer agents. However, emerging data suggests that hypomethylation plays a role in activating genes required for metastasis and invasion. It is proposed here that hypermethylation and hypomethylation in cancer are independent processes, which target different programs at different stages in tumorigenesis. Understanding the relative roles of hypomethylation and hypermethylation in cancer has clear implications on the therapeutic use of agents targeting the DNA methylation machinery, which are discussed in this review.
Collapse
Affiliation(s)
- Moshe Szyf
- Department of Pharmacology and Therapeutics, McGill University, 3655 Sir William Osler Promenade, Montreal, Que., Canada PQ H3G 1Y6.
| | | | | |
Collapse
|
40
|
Pakneshan P, Szyf M, Farias-Eisner R, Rabbani SA. Reversal of the hypomethylation status of urokinase (uPA) promoter blocks breast cancer growth and metastasis. J Biol Chem 2004; 279:31735-44. [PMID: 15150277 DOI: 10.1074/jbc.m401669200] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Metastasis is a leading cause of mortality and morbidity in cancer. Urokinase (uPA), only expressed by the highly invasive cancer cells, has been implicated in invasion, metastases, and angiogenesis of several malignancies including breast cancer. Because uPA expression is strongly correlated with its hypomethylated state, we utilized the uPA gene in the highly invasive MDA-231 human breast cancer cells as a model system to test the hypothesis that pharmacological reversal of the uPA promoter hypomethylation would result in its silencing and inhibition of metastasis. S-Adenosyl-l-methionine (AdoMet) has previously been shown to cause hypermethylation and inhibit demethylation. Treatment of MDA-231 cells with AdoMet, but not its unmethylated analogue S-adenosylhomocysteine, significantly inhibits uPA expression and tumor cell invasion in vitro and tumor growth and metastasis in vivo. The effects of AdoMet on uPA expression were reversed by the demethylating agent 5'-azacytidine, supporting the conclusion that AdoMet effects are caused by hypermethylation. Knockdown of the methyl-binding protein 2 also causes a significant inhibition of uPA expression in vitro and tumor growth and metastasis in vivo. These treatments did not have any effects on estrogen receptor expression, suggesting that inhibition of hypomethylation will not affect genes already silenced by hypermethylation. These data are consistent with the hypothesis that hypomethylation of critical genes like uPA plays a causal role in metastasis. Inhibition of hypomethylation can thus be used as a novel therapeutic approach to silence the pro-metastatic gene uPA and block breast cancer progression into the aggressive and metastatic stages of the disease.
Collapse
Affiliation(s)
- Pouya Pakneshan
- Department of Medicine, McGill University, Montreal H3A 1A1, Canada
| | | | | | | |
Collapse
|
41
|
Milutinovic S, Brown SE, Zhuang Q, Szyf M. DNA methyltransferase 1 knock down induces gene expression by a mechanism independent of DNA methylation and histone deacetylation. J Biol Chem 2004; 279:27915-27. [PMID: 15087453 DOI: 10.1074/jbc.m312823200] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DNA methyltransferase 1 (DNMT1) catalyzes the post-replication methylation of DNA and is responsible for maintaining the DNA methylation pattern during cell division. A long list of data supports a role for DNMT1 in cellular transformation and inhibitors of DNMT1 were shown to have antitumorigenic effects. It was long believed that DNMT1 promoted tumorigenesis by maintaining the hypermethylated and silenced state of tumor suppressor genes. We have previously shown that DNMT1 knock down by either antisense oligonucleotides directed at DNMT1 or expressed antisense activates a number of genes involved in stress response and cell cycle arrest by a DNA methylation-independent mechanism. In this report we demonstrate that antisense knock down of DNMT1 in human lung carcinoma A549 and embryonal kidney HEK293 cells induces gene expression by a mechanism that does not involve either of the known epigenomic mechanisms, DNA methylation, histone acetylation, or histone methylation. The mechanism of activation of the cell cycle inhibitor p21 and apoptosis inducer BIK by DNMT1 inhibition is independent of the mechanism of activation of the same genes by histone deacetylase inhibition. We determine whether DNMT1 knock down activates one of the nodal transcription activation pathways in the cell and demonstrate that DNMT1 activates Sp1 response elements. This activation of Sp1 response does not involve an increase in either Sp1 or Sp3 protein levels in the cell or the occupancy of the Sp1 elements with these proteins. The methylation-independent regulation of Sp1 elements by DNMT1 unravels a novel function for DNMT1 in gene regulation. DNA methylation was believed to be a mechanism for suppression of CG-rich Sp1-bearing promoters. Our data suggest a fundamentally different and surprising role for DNMT1 regulation of CG-rich genes by a mechanism independent of DNA methylation and histone acetylation. The implications of our data on the biological roles of DNMT1 and the therapeutic potential of DNMT1 inhibitors as anticancer agents are discussed.
Collapse
Affiliation(s)
- Snezana Milutinovic
- Department of Pharmacology and Therapeutics, McGill University, 3655 Sir William Osler Promenade, Montreal, Quebec H3G 1Y6, Canada
| | | | | | | |
Collapse
|
42
|
Abstract
An emerging body of literature indicates that reversible alterations in chromatin structure modulate gene expression during malignant transformation. Chromatin structure is regulated in part by DNA methylation and histone acetylation; these independent yet highly interrelated epigenetic processes are influenced by a variety of signal transduction pathways. The present review highlights recent advances regarding cancer epigenetics, focusing on the potential utilization of chromatin remodeling agents to induce apoptosis and enhance the immunogenicity of thoracic malignancies.
Collapse
Affiliation(s)
- David S Schrump
- Thoracic Oncology Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA.
| |
Collapse
|
43
|
Zhu WG, Hileman T, Ke Y, Wang P, Lu S, Duan W, Dai Z, Tong T, Villalona-Calero MA, Plass C, Otterson GA. 5-aza-2'-deoxycytidine activates the p53/p21Waf1/Cip1 pathway to inhibit cell proliferation. J Biol Chem 2004; 279:15161-6. [PMID: 14722112 DOI: 10.1074/jbc.m311703200] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In addition to its demethylating function, 5-aza-2'-deoxycytidine (5-aza-CdR) also plays an important role in inducing cell cycle arrest, differentiation, and cell death. However, the mechanism by which 5-aza-CdR induces antineoplastic activity is not clear. In this study, we found that 5-aza-CdR at limited concentrations (0.01-5 microm) induces inhibition of cell proliferation as well as increased p53/p21(Waf1/Cip1) expression in A549 cells (wild-type p53) but not in H1299 (p53-null) and H719 cells (p53 mutant). The p53-dependent p21(Waf1/Cip1) expression induced by 5-aza-CdR was not seen in A549 cells transfected with the wild-type human papilloma virus type-16 E6 gene that induces p53 degradation. Furthermore, deletion analysis and site-directed mutagenesis of the p21 promoter reveals that 5-aza-CdR induces p21(Waf1/Cip1) expression through two p53 binding sites in the p21 promoter. Finally, 5-aza-CdR-induced p21(Waf1/Cip1) expression was dependent on DNA damage but not on DNA demethylation as demonstrated by comet assay and bisulfite sequencing, respectively. Our data provide useful clues for judging the therapeutic efficacy of 5-aza-CdR in the treatment of human cancer cells.
Collapse
Affiliation(s)
- Wei-Guo Zhu
- Department of Biochemistry and Molecular Biology, University of Health Science Center, Beijing, China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Affiliation(s)
- James G Herman
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Johns Hopkins Medical Institutions, Baltimore, USA.
| | | |
Collapse
|
45
|
Soejima K, Fang W, Rollins BJ. DNA methyltransferase 3b contributes to oncogenic transformation induced by SV40T antigen and activated Ras. Oncogene 2003; 22:4723-33. [PMID: 12879017 DOI: 10.1038/sj.onc.1206510] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2003] [Revised: 02/11/2003] [Accepted: 02/17/2003] [Indexed: 01/03/2023]
Abstract
Transcriptional silencing of tumor suppressor genes in association with DNA methylation contributes to malignant transformation. However, the specific DNA methyltransferases that initiate this process are unknown. Here we show that a de novo DNA methyltransferase, DNMT3b, substantially contributes to the oncogenic phenotype in a lung cancer model. Normal human bronchial epithelial (NHBE) cells expressing telomerase, SV40 large T antigen, and activated Ras were immortal, formed colonies in soft agar, and expressed DNMT3b. Antisense suppression of DNMT3b prevented soft agar growth. Furthermore, mouse embryo fibroblasts expressing T antigen and Ras formed soft agar colonies and large tumors, but fibroblasts from Dnmt3b(-/-) mice did not grow in soft agar and were much less tumorigenic in vivo. The tumor suppressor genes, FHIT, TSLC1, and RASSF1A were downregulated in transformed NHBE cells, and antisense DNMT3b treatment resulted in re-expression of FHIT and TSLC1. While expression of TSCL1 correlated with methylation of CpG dinucleotides in its promoter region, the expression of FHIT did not, suggesting that DNMT3b may silence genes by several mechanisms including direct DNA methylation or recruitment of proteins that modify chromatin. Regardless of mechanism, our data indicate that DNMT3b plays an important role in transformation.
Collapse
Affiliation(s)
- Kenzo Soejima
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | | |
Collapse
|
46
|
Young JI, Sedivy JM, Smith JR. Telomerase expression in normal human fibroblasts stabilizes DNA 5-methylcytosine transferase I. J Biol Chem 2003; 278:19904-8. [PMID: 12665523 DOI: 10.1074/jbc.m301685200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The finite proliferative potential of normal human fibroblasts can be overcome, a process commonly called immortalization, by the introduction of the catalytic subunit of human telomerase. In contrast to malignant transformation, the pattern of gene expression remains largely unmodified in telomerase-induced immortalization. Here we show evidence that suggests that the maintenance of a "young" pattern of gene expression by telomerization is mediated, at least in part, by a novel function of human telomerase that involves regulation of DNA methyltransferase I gene expression.
Collapse
Affiliation(s)
- Juan I Young
- Roy M. and Phyllis Gough Huffington Center on Aging, Baylor College of Medicine, Houston, Texas 77030, USA.
| | | | | |
Collapse
|
47
|
Gaudet F, Hodgson JG, Eden A, Jackson-Grusby L, Dausman J, Gray JW, Leonhardt H, Jaenisch R. Induction of tumors in mice by genomic hypomethylation. Science 2003; 300:489-92. [PMID: 12702876 DOI: 10.1126/science.1083558] [Citation(s) in RCA: 1076] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Genome-wide DNA hypomethylation occurs in many human cancers, but whether this epigenetic change is a cause or consequence of tumorigenesis has been unclear. To explore this phenomenon, we generated mice carrying a hypomorphic DNA methyltransferase 1 (Dnmt1) allele, which reduces Dnmt1 expression to 10% of wild-type levels and results in substantial genome-wide hypomethylation in all tissues. The mutant mice were runted at birth, and at 4 to 8 months of age they developed aggressive T cell lymphomas that displayed a high frequency of chromosome 15 trisomy. These results indicate that DNA hypomethylation plays a causal role in tumor formation, possibly by promoting chromosomal instability.
Collapse
Affiliation(s)
- François Gaudet
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | | | | | | | | | | | | | | |
Collapse
|
48
|
Hopkins-Donaldson S, Ziegler A, Kurtz S, Bigosch C, Kandioler D, Ludwig C, Zangemeister-Wittke U, Stahel R. Silencing of death receptor and caspase-8 expression in small cell lung carcinoma cell lines and tumors by DNA methylation. Cell Death Differ 2003; 10:356-64. [PMID: 12700635 DOI: 10.1038/sj.cdd.4401157] [Citation(s) in RCA: 188] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Small cell lung cancer cell lines were resistant to FasL and TRAIL-induced apoptosis, which could be explained by an absence of Fas and TRAIL-R1 mRNA expression and a deficiency of surface TRAIL-R2 protein. In addition, caspase-8 expression was absent, whereas FADD, FLIP and caspases-3, -7, -9 and -10 could be detected. Analysis of SCLC tumors revealed reduced levels of Fas, TRAIL-R1 and caspase-8 mRNA compared to non-small cell lung cancer (NSCLC) tumors. Methylation-specific PCR demonstrated methylation of CpG islands of the Fas, TRAIL-R1 and caspase-8 genes in SCLC cell lines and tumor samples, whereas NSCLC samples were not methylated. Cotreatment of SCLC cells with the demethylating agent 5'-aza-2-deoxycytidine and IFNgamma partially restored Fas, TRAIL-R1 and caspase-8 expression and increased sensitivity to FasL and TRAIL-induced death. These results suggest that SCLC cells are highly resistant to apoptosis mediated by death receptors and that this resistance can be reduced by a combination of demethylation and treatment with IFNgamma.
Collapse
|
49
|
Alcock RA, Dey S, Chendil D, Inayat MS, Mohiuddin M, Hartman G, Chatfield LK, Gallicchio VS, Ahmed MM. Farnesyltransferase inhibitor (L-744,832) restores TGF-beta type II receptor expression and enhances radiation sensitivity in K-ras mutant pancreatic cancer cell line MIA PaCa-2. Oncogene 2002; 21:7883-90. [PMID: 12420225 DOI: 10.1038/sj.onc.1205948] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2002] [Revised: 07/31/2002] [Accepted: 08/07/2002] [Indexed: 11/09/2022]
Abstract
Activated ras is known to dysregulate TGF-beta signaling by altering the expression of TGF-beta type II receptor (RII). It is well documented that tumor cells harboring mutant ras are more resistant to radiation than cells with wild-type ras. In this study, we hypothesized that the use of farnesyltransferase inhibitor (FTI, L-744,832) may directly restore TGF-beta signaling through RII expression via ras dependent or independent pathway leading to induction of radiation sensitivity. Two pancreatic cancer cell lines, BxPC-3 and MIA PaCa-2 were used in this study. FTI inhibited farnesylation of Ras protein more significantly in MIA PaCa-2 than BxPC-3 cells. In contrast, MIA PaCa-2 cells were resistant to radiation when compared to BxPC-3 cells. BxPC-3 cells were more resistant to FTI than MIA PaCa-2 cells. In combination treatment, no significant radiosensitizing effect of FTI was observed in BxPC-3 cells at 5 or 10 microM. However, in MIA PaCa-2 cells, a significant radiosensitizing effect was observed at both 5 and 10 microM concentrations (P>0.004). The TGF-beta effector gene p21(waf1/cip1) was elevated in combination treatment in MIA PaCa-2 but not in BxPC-3 cells. In MIA PaCa-2 cells, FTI induced TGF-beta responsive promoter activity as assessed by 3TP-luciferase activity. A further induction of luciferase activity was observed in MIA PaCa-2 cells treated with radiation and FTI. Induction of TGF-beta signaling by FTI was mediated through restoration of the RII expression, as demonstrated by RT-PCR analysis. In addition, re-expression of RII by FTI was associated with a decrease in DNA methyltransferase 1 (DNMT1) levels. Thus, these findings suggest that the L-744,832 treatment restores the RII expression through inhibition of DNMT1 levels causing induction of TGF-beta signaling by radiation and this forms a novel molecular mechanism of radiosensitization by FTI.
Collapse
Affiliation(s)
- Rachael A Alcock
- Department of Radiation Medicine, University of Kentucky, Lexington, Kentucky 40536, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Guo Y, Pakneshan P, Gladu J, Slack A, Szyf M, Rabbani SA. Regulation of DNA methylation in human breast cancer. Effect on the urokinase-type plasminogen activator gene production and tumor invasion. J Biol Chem 2002; 277:41571-9. [PMID: 12198113 DOI: 10.1074/jbc.m201864200] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Urokinase-type plasminogen activator (uPA) is a member of the serine protease family and can break down various components of the extracellular matrix to promote growth, invasion, and metastasis of several malignancies including breast cancer. In the current study we examined the role that the DNA methylation machinery might be playing in regulating differential uPA gene expression in breast cancer cell lines. uPA mRNA is expressed in the highly invasive, hormone-insensitive human breast cancer cell line MDA-MB-231 but not in hormone-responsive cell line MCF-7. Using methylation-sensitive PCR, we show that 90% of CpG dinucleotides in the uPA promoter are methylated in MCF-7 cells, whereas fully demethylated CpGs were detected in MDA-MB-231 cells. uPA promoter activity, which is directly regulated by the Ets-1 transcription factor, is inhibited by methylation as determined by uPA promoter-luciferase reporter assays. We then tested whether the state of expression and methylation of the uPA promoter correlates with the global level of DNA methyltransferase and demethylase activities in these cell lines. We show that maintenance DNA methyltransferase activity is significantly higher in MCF-7 cells than in MDA-MB-231 cells, whereas demethylase activity is higher in MDA-MB-231 cells. We suggest that the combination of increased DNA methyltransferase activity with reduced demethylase activity contributes to the methylation and silencing of uPA expression in MCF-7 cells. The converse is true in MDA-MB-231 cells, which represents a late stage highly invasive breast cancer. The histone deacetylase inhibitor, Trichostatin A, induces the expression of the uPA gene in MDA-MB-231 cells but not in MCF-7 cells. This supports the hypothesis that DNA methylation is the dominant mechanism involved in the silencing of uPA gene expression. Taken together, these results provide insight into the mechanism regulating the transcription of the uPA gene in the complex multistep process of breast cancer progression.
Collapse
Affiliation(s)
- Yongjing Guo
- Departments of Medicine and Pharmacology, McGill University Health Center, Montreal, Quebec H3A 1A1, Canada
| | | | | | | | | | | |
Collapse
|