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Aftabizadeh M, Li YJ, Zhao Q, Zhang C, Ambaye N, Song J, Nagao T, Lahtz C, Fakih M, Ann DK, Yu H, Herrmann A. Potent antitumor effects of cell-penetrating peptides targeting STAT3 axis. JCI Insight 2021; 6:136176. [PMID: 33491667 PMCID: PMC7934871 DOI: 10.1172/jci.insight.136176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 12/09/2020] [Indexed: 01/05/2023] Open
Abstract
To date, there are no inhibitors that directly and specifically target activated STAT3 and c-Myc in the clinic. Although peptide-based inhibitors can selectively block activated targets, their clinical usage is limited because of low cell penetration and/or serum stability. Here, we generated cell-penetrating acetylated (acet.) STAT3, c-Myc, and Gp130 targeting peptides by attaching phosphorothioated (PS) polymer backbone to peptides. The cell-penetrating peptides efficiently penetrated cells and inhibited activation of the intended targets and their downstream genes. Locally or systemically treating tumor-bearing mice with PS-acet.-STAT3 peptide at low concentrations effectively blocked STAT3 in vivo, resulting in significant antitumor effects in 2 human xenograft models. Moreover, PS-acet.-STAT3 peptide penetrated and activated splenic CD8+ T cells in vitro. Treating immune-competent mice bearing mouse melanoma with PS-acet.-STAT3 peptide inhibited STAT3 in tumor-infiltrating T cells, downregulating tumor-infiltrating CD4+ T regulatory cells while activating CD8+ T effector cells. Similarly, systemic injections of the cell-penetrating c-Myc and Gp130 peptides prevented pancreatic tumor growth and induced antitumor immune responses. Taken together, we have developed therapeutic peptides that effectively and specifically block challenging cancer targets, resulting in antitumor effects through both direct tumor cell killing and indirectly through antitumor immune responses.
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Affiliation(s)
| | | | - Qianqian Zhao
- Department of Immuno-Oncology and.,Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | | | | | | | | | - Christoph Lahtz
- Department of Immuno-Oncology and.,Sorrento Therapeutics, San Diego, California, USA
| | - Marwan Fakih
- Department of Medical Oncology and Therapeutics and
| | - David K Ann
- Diabetes & Metabolism Research Institute, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Hua Yu
- Department of Immuno-Oncology and
| | - Andreas Herrmann
- Department of Immuno-Oncology and.,Sorrento Therapeutics, San Diego, California, USA
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Herrmann A, Nagao T, Zhang C, Lahtz C, Li YJ, Yue C, Mülfarth R, Yu H. An effective cell-penetrating antibody delivery platform. JCI Insight 2019; 4:127474. [PMID: 31341104 DOI: 10.1172/jci.insight.127474] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 05/31/2019] [Indexed: 12/25/2022] Open
Abstract
Despite their well-recognized success in the clinic, antibodies generally do not penetrate cellular membranes to target intracellular molecules, many of which underlie incurable diseases. Here we show that covalently conjugating phosphorothioated DNA oligonucleotides to antibodies enabled their efficient cellular internalization. Antibody cell penetration was partially mediated by membrane potential alteration. Moreover, without an antigen to bind, intracellular levels of the modified antibodies underwent cellular clearance, which involved efflux and lysosomal degradation, enabling detection of intended intracellular molecules as tested in fibroblasts, tumor cells, and T cells. This target-dependent cellular retention of modified antibodies extended to in vivo studies. Both local and systemic administrations of low doses of modified antibodies effectively inhibited intracellular targets, such as transcription factors Myc, interferon regulatory factor 4, and tyrosine-protein kinase SRC, and expression of their downstream genes in tumors, resulting in tumor cell apoptosis and tumor growth inhibition. This simple modification enables the use of antibodies to detect and modulate intracellular molecules in both cultured living cells and in whole animals, forming the foundation for a new paradigm for antibody-based research, diagnostics, and therapeutics.
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Affiliation(s)
- Andreas Herrmann
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA.,LACell at Sorrento Therapeutics, San Diego, California, USA
| | - Toshikage Nagao
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Chunyan Zhang
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Christoph Lahtz
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA.,LACell at Sorrento Therapeutics, San Diego, California, USA
| | - Yi-Jia Li
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Chanyu Yue
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA.,LACell at Sorrento Therapeutics, San Diego, California, USA
| | - Ronja Mülfarth
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Hua Yu
- Department of Immuno-Oncology, Beckman Research Institute at City of Hope Comprehensive Cancer Center, Duarte, California, USA
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3
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Herrmann A, Lahtz C, Nagao T, Song JY, Chan WC, Lee H, Yue C, Look T, Mülfarth R, Li W, Jenkins K, Williams J, Budde LE, Forman S, Kwak L, Blankenstein T, Yu H. CTLA4 Promotes Tyk2-STAT3-Dependent B-cell Oncogenicity. Cancer Res 2017; 77:5118-5128. [PMID: 28716895 DOI: 10.1158/0008-5472.can-16-0342] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 05/04/2017] [Accepted: 07/07/2017] [Indexed: 12/21/2022]
Abstract
CTL-associated antigen 4 (CTLA4) is a well-established immune checkpoint for antitumor immune responses. The protumorigenic function of CTLA4 is believed to be limited to T-cell inhibition by countering the activity of the T-cell costimulating receptor CD28. However, as we demonstrate here, there are two additional roles for CTLA4 in cancer, including via CTLA4 overexpression in diverse B-cell lymphomas and in melanoma-associated B cells. CTLA4-CD86 ligation recruited and activated the JAK family member Tyk2, resulting in STAT3 activation and expression of genes critical for cancer immunosuppression and tumor growth and survival. CTLA4 activation resulted in lymphoma cell proliferation and tumor growth, whereas silencing or antibody-blockade of CTLA4 in B-cell lymphoma tumor cells in the absence of T cells inhibits tumor growth. This inhibition was accompanied by reduction of Tyk2/STAT3 activity, tumor cell proliferation, and induction of tumor cell apoptosis. The CTLA4-Tyk2-STAT3 signal pathway was also active in tumor-associated nonmalignant B cells in mouse models of melanoma and lymphoma. Overall, our results show how CTLA4-induced immune suppression occurs primarily via an intrinsic STAT3 pathway and that CTLA4 is critical for B-cell lymphoma proliferation and survival. Cancer Res; 77(18); 5118-28. ©2017 AACR.
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Affiliation(s)
- Andreas Herrmann
- Department of Onco-Immunology, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California.
| | - Christoph Lahtz
- Department of Onco-Immunology, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Toshikage Nagao
- Department of Onco-Immunology, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California.,Department of Hematology, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Joo Y Song
- Department of Pathology, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Wing C Chan
- Department of Pathology, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Heehyoung Lee
- Department of Onco-Immunology, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Chanyu Yue
- Department of Onco-Immunology, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Thomas Look
- Department of Onco-Immunology, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Ronja Mülfarth
- Department of Onco-Immunology, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Wenzhao Li
- Department of Onco-Immunology, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Kurt Jenkins
- Department of Molecular Medicine, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - John Williams
- Department of Molecular Medicine, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Lihua E Budde
- Hematology Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Stephen Forman
- Hematology Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Larry Kwak
- Hematology Institute, City of Hope Comprehensive Cancer Center, Duarte, California
| | - Thomas Blankenstein
- Max-Delbrück-Center for Molecular Medicine, and the Institute of Immunology, Charité Campus Buch, Berlin, Germany
| | - Hua Yu
- Department of Onco-Immunology, Beckman Research Institute, City of Hope Comprehensive Cancer Center, Duarte, California.
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Herrmann A, Priceman SJ, Swiderski P, Kujawski M, Xin H, Cherryholmes GA, Zhang W, Zhang C, Lahtz C, Kowolik C, Forman SJ, Kortylewski M, Yu H. CTLA4 aptamer delivers STAT3 siRNA to tumor-associated and malignant T cells. J Clin Invest 2015; 125:2547. [PMID: 26030229 DOI: 10.1172/jci82555] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Herrmann A, Cherryholmes G, Schroeder A, Phallen J, Alizadeh D, Xin H, Wang T, Lee H, Lahtz C, Swiderski P, Armstrong B, Kowolik C, Gallia GL, Lim M, Brown C, Badie B, Forman S, Kortylewski M, Jove R, Yu H. TLR9 is critical for glioma stem cell maintenance and targeting. Cancer Res 2014; 74:5218-28. [PMID: 25047528 DOI: 10.1158/0008-5472.can-14-1151] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Understanding supports for cancer stem-like cells in malignant glioma may suggest therapeutic strategies for their elimination. Here, we show that the Toll-like receptor TLR9 is elevated in glioma stem-like cells (GSC) in which it contributes to glioma growth. TLR9 overexpression is regulated by STAT3, which is required for GSC maintenance. Stimulation of TLR9 with a CpG ligand (CpG ODN) promoted GSC growth, whereas silencing TLR9 expression abrogated GSC development. CpG-ODN treatment induced Frizzled4-dependent activation of JAK2, thereby activating STAT3. Targeted delivery of siRNA into GSC was achieved via TLR9 using CpG-siRNA conjugates. Through local or systemic treatment, administration of CpG-Stat3 siRNA to silence STAT3 in vivo reduced GSC along with glioma growth. Our findings identify TLR9 as a functional marker for GSC and a target for the delivery of efficacious therapeutics for glioma treatment. Cancer Res; 74(18); 5218-28. ©2014 AACR.
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Affiliation(s)
- Andreas Herrmann
- Department of Cancer Immunotherapeutics and Tumor Immunology, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Gregory Cherryholmes
- Department of Cancer Immunotherapeutics and Tumor Immunology, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Anne Schroeder
- Department of Molecular Medicine, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Jillian Phallen
- Department of Neurosurgery at the Sidney Kimmel Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Darya Alizadeh
- Division of Neurosurgery, City of Hope Medical Center, Duarte, California
| | - Hong Xin
- Department of Cancer Immunotherapeutics and Tumor Immunology, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Tianyi Wang
- Department of Cancer Immunotherapeutics and Tumor Immunology, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Heehyoung Lee
- Department of Cancer Immunotherapeutics and Tumor Immunology, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Christoph Lahtz
- Department of Cancer Immunotherapeutics and Tumor Immunology, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Piotr Swiderski
- Department of Molecular Medicine, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Brian Armstrong
- Department of Neuroscience, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Claudia Kowolik
- Department of Molecular Medicine, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Gary L Gallia
- Department of Neurosurgery at the Sidney Kimmel Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Michael Lim
- Department of Neurosurgery at the Sidney Kimmel Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Christine Brown
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope Medical Center, Duarte, California
| | - Behnam Badie
- Division of Neurosurgery, City of Hope Medical Center, Duarte, California
| | - Stephen Forman
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope Medical Center, Duarte, California
| | - Marcin Kortylewski
- Department of Cancer Immunotherapeutics and Tumor Immunology, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Richard Jove
- Department of Molecular Medicine, Beckman Research Institute at City of Hope Medical Center, Duarte, California
| | - Hua Yu
- Department of Cancer Immunotherapeutics and Tumor Immunology, Beckman Research Institute at City of Hope Medical Center, Duarte, California. Center for Translational Medicine, Shanghai Zhangjiang High-Tech Park, Shanghai, China.
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Herrmann A, Priceman SJ, Swiderski P, Kujawski M, Xin H, Cherryholmes GA, Zhang W, Zhang C, Lahtz C, Kowolik C, Forman SJ, Kortylewski M, Yu H. CTLA4 aptamer delivers STAT3 siRNA to tumor-associated and malignant T cells. J Clin Invest 2014; 124:2977-87. [PMID: 24892807 DOI: 10.1172/jci73174] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 04/10/2014] [Indexed: 01/05/2023] Open
Abstract
Intracellular therapeutic targets that define tumor immunosuppression in both tumor cells and T cells remain intractable. Here, we have shown that administration of a covalently linked siRNA to an aptamer (apt) that selectively binds cytotoxic T lymphocyte-associated antigen 4 (CTLA4(apt)) allows gene silencing in exhausted CD8⁺ T cells and Tregs in tumors as well as CTLA4-expressing malignant T cells. CTLA4 expression was upregulated in CD8⁺ T cells in the tumor milieu; therefore, CTLA4(apt) fused to a STAT3-targeting siRNA (CTLA4(apt)-STAT3 siRNA) resulted in internalization into tumor-associated CD8⁺ T cells and silencing of STAT3, which activated tumor antigen-specific T cells in murine models. Both local and systemic administration of CTLA4(apt)-STAT3 siRNA dramatically reduced tumor-associated Tregs. Furthermore, CTLA4(apt)-STAT3 siRNA potently inhibited tumor growth and metastasis in various mouse tumor models. Importantly, CTLA4 expression is observed in T cells of patients with blood malignancies, and CTLA4(apt)-STAT3 siRNA treatment of immunodeficient mice bearing human T cell lymphomas promoted tumor cell apoptosis and tumor growth inhibition. These data demonstrate that a CTLA4(apt)-based siRNA delivery strategy allows gene silencing in both tumor-associated T cells and tumor cells and inhibits tumor growth and metastasis.
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MESH Headings
- Animals
- Aptamers, Nucleotide/administration & dosage
- Aptamers, Nucleotide/genetics
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- CTLA-4 Antigen/genetics
- Cell Line, Tumor
- Gene Silencing
- Humans
- Immunotherapy, Adoptive/methods
- Lymphocytes, Tumor-Infiltrating/immunology
- Lymphocytes, Tumor-Infiltrating/metabolism
- Lymphoma, T-Cell/immunology
- Lymphoma, T-Cell/therapy
- Melanoma, Experimental/immunology
- Melanoma, Experimental/therapy
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Nude
- RNA, Small Interfering/administration & dosage
- RNA, Small Interfering/genetics
- STAT3 Transcription Factor/antagonists & inhibitors
- STAT3 Transcription Factor/genetics
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
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7
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Abstract
Unprotected exposure to UVB radiation from the sun and the resulting DNA damage are thought to be responsible for physiological changes in the skin and for a variety of skin cancers, including basal cell and squamous cell carcinoma and malignant melanoma. Although the mutagenic effects of UVB have been well documented and studied mechanistically, there is only limited information as to whether UV light may also be responsible for inducing epigenetic changes in the genome of exposed cells. DNA methylation is a stable epigenetic modification involved in gene control. To study the effects of UVB radiation on DNA methylation, we repeatedly exposed normal human keratinocytes to a UVB light source. After a recovery period, we analyzed global DNA methylation patterns in the irradiated and control cells using the methylated-CpG island recovery assay (MIRA) method in combination with high-resolution microarrays. Bioinformatics analysis revealed only a limited number of possible differences between UVB-exposed and control cells. However, these minor apparent changes could not be independently confirmed by bisulfite sequencing-based approaches. This study reveals that UVB irradiation of keratinocytes has no recognizable global effect on DNA methylation patterns and suggests that changes in DNA methylation, as observed in skin cancers, are not immediate consequences of human exposure to solar UVB irradiation.
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Affiliation(s)
- Christoph Lahtz
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, 91010, USA
| | - Sang-In Kim
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, 91010, USA
| | - Steven E Bates
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, 91010, USA
| | - Arthur X Li
- Department of Information Sciences, Beckman Research Institute, City of Hope, Duarte, 91010, USA
| | - Xiwei Wu
- Department of Molecular Medicine, Beckman Research Institute, City of Hope, Duarte, 91010, USA
| | - Gerd P Pfeifer
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, 91010, USA
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Lahtz C, Bates SE, Jiang Y, Li AX, Wu X, Hahn MA, Pfeifer GP. Gamma irradiation does not induce detectable changes in DNA methylation directly following exposure of human cells. PLoS One 2012; 7:e44858. [PMID: 23024770 PMCID: PMC3443085 DOI: 10.1371/journal.pone.0044858] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 08/07/2012] [Indexed: 12/05/2022] Open
Abstract
Environmental chemicals and radiation have often been implicated in producing alterations of the epigenome thus potentially contributing to cancer and other diseases. Ionizing radiation, released during accidents at nuclear power plants or after atomic bomb explosions, is a potentially serious health threat for the exposed human population. This type of high-energy radiation causes DNA damage including single- and double-strand breaks and induces chromosomal rearrangements and mutations, but it is not known if ionizing radiation directly induces changes in the epigenome of irradiated cells. We treated normal human fibroblasts and normal human bronchial epithelial cells with different doses of γ-radiation emitted from a cesium 137 (137Cs) radiation source. After a seven-day recovery period, we analyzed global DNA methylation patterns in the irradiated and control cells using the methylated-CpG island recovery assay (MIRA) in combination with high-resolution microarrays. Bioinformatics analysis revealed only a small number of potential methylation changes with low fold-difference ratios in the irradiated cells. These minor methylation differences seen on the microarrays could not be verified by COBRA (combined bisulfite restriction analysis) or bisulfite sequencing of selected target loci. Our study shows that acute γ-radiation treatment of two types of human cells had no appreciable direct effect on DNA cytosine methylation patterns in exposed cells.
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Affiliation(s)
- Christoph Lahtz
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, California, United States of America
| | - Steven E. Bates
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, California, United States of America
| | - Yong Jiang
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, California, United States of America
| | - Arthur X. Li
- Department of Information Sciences, City of Hope, Duarte, California, United States of America
| | - Xiwei Wu
- Department of Molecular Medicine, City of Hope, Duarte, California, United States of America
| | - Maria A. Hahn
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, California, United States of America
| | - Gerd P. Pfeifer
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, California, United States of America
- * E-mail:
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9
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Abstract
'Every Hour Hurts, The Last One Kills'. That is an old saying about getting old. Every day, thousands of DNA damaging events take place in each cell of our body, but efficient DNA repair systems have evolved to prevent that. However, our DNA repair system and that of most other organisms are not as perfect as that of Deinococcus radiodurans, for example, which is able to repair massive amounts of DNA damage at one time. In many instances, accumulation of DNA damage has been linked to cancer, and genetic deficiencies in specific DNA repair genes are associated with tumor-prone phenotypes. In addition to mutations, which can be either inherited or somatically acquired, epigenetic silencing of DNA repair genes may promote tumorigenesis. This review will summarize current knowledge of the epigenetic inactivation of different DNA repair components in human cancer.
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Affiliation(s)
- Christoph Lahtz
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, CA 91010, USA
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10
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Helmbold P, Lahtz C, Enk A, Herrmann-Trost P, Marsch WC, Kutzner H, Dammann RH. Frequent occurrence ofRASSF1Apromoter hypermethylation and merkel cell polyomavirus in merkel cell carcinoma. Mol Carcinog 2009; 48:903-9. [DOI: 10.1002/mc.20540] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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11
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Lahtz C, Stranzenbach R, Fiedler E, Helmbold P, Dammann RH. Methylation of PTEN as a prognostic factor in malignant melanoma of the skin. J Invest Dermatol 2009; 130:620-2. [PMID: 19798057 DOI: 10.1038/jid.2009.226] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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12
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Rastetter M, Schagdarsurengin U, Lahtz C, Fiedler E, Marsch WC, Dammann R, Helmbold P. Frequent intra-tumoural heterogeneity of promoter hypermethylation in malignant melanoma. Histol Histopathol 2007; 22:1005-15. [PMID: 17523078 DOI: 10.14670/hh-22.1005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To investigate intra-tumoural coexistence and heterogeneity of aberrant promoter hypermethylation of different tumour suppressor genes in melanoma, we analyzed the intra-tumoural distribution of promoter methylation of RASSF1A, p16, DAPK, MGMT, and Rb in 339 assays of 34 tumours (15 melanoma primaries, 19 metastases) by methylation-specific PCR, correlation to histopathology and RASSF1A expression. We detected promoter hypermethylation of at least one gene in 74% of tumours (30%, 52%, 33%, 20%, and 40% for RASSF1A, p16, DAPK, MGMT and Rb, respectively). 70% of the cases exhibited an inhomogeneous methylation pattern (17%, 45%, 33%, 20%, and 40% for RASSF1A, p16, DAPK, MGMT and Rb, respectively). Samples from the core of the tumours represented the methylation state of the whole tumours more accurately than the periphery. Local intra-tumoural correlation was found between the promoter hypermethylation state of p16 and Rb or p16 and DAPK, or epitheloid tumour cell type and RASSF1A or p16 methylation. Mitosis rate and sex was correlated with methylation of RASSF1A. Histological results confirmed that promoter hypermethylation of RASSF1A led to aberrant expression patterns. We conclude that intra-tumoural inhomogeneity of promoter hypermethylation is frequent in melanoma and this supports the hypothesis of clonal instability during progression of melanomas. In prognosis studies, missing the intra-tumoural sample representativeness may result in a reduction of the sensitivities or specificities.
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Affiliation(s)
- M Rastetter
- AWG Tumour Genetics of the Medical Faculty, Martin Luther University Halle-Wittenberg, Germany
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