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Tiwari R, Baratchian M, Berk M, Li J, Guerinot A, Makarov V, Chan TA, Chakraborty AA, Sharifi N. Abstract A019: Epigenetic regulation by H3K9 methylation enables resistance to anti-androgen therapy in prostate cancer. Cancer Res 2022. [DOI: 10.1158/1538-7445.cancepi22-a019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Abstract
Prostate cancer (PCa) is a major cause of cancer mortality in the United States. Androgen receptor (AR) is the key transcriptional regulator for the development and progression of prostate cancer. Androgen deprivation therapy (ADT) with medical castration and treatment with second-generation anti-androgens such as enzalutamide and abiraterone acetate are important treatments for advanced prostate cancer. Previous studies have shown resistance to enzalutamide develops through various alternative molecular mechanisms including AR gene amplification, mutations in the ligand binding domains of AR, and increased expression of glucocorticoid receptor (GR). Recent reports further indicate that resistance to enzalutamide is accompanied with various de novo genomic and transcriptional changes that lead to reduced AR activity and acquisition of stem-cell like properties along with increased expression of genes associated with epithelial-to-mesenchymal transition and inflammatory signaling pathway, including interleukin 6 (IL6), janus kinase-signal transducer and activator of transcription (JAK-STAT) and interferon (IFN). In our study, we have unraveled a novel mechanism of epigenetic regulation mediated by H3K9 methylation in response to anti-androgen treatment in PCa cells. We have shown enzalutamide treatment leads to aberrant activation of endogenous retroelements (REs) which causes accumulation of double stranded RNA (dsRNA) in the PCa cells. This results in an antiviral response mediated via IFN signaling and induction of apoptosis, a phenomenon known as viral mimicry. Using a forward genetic screen, we have identified that the epigenetic machinery associated with H3K9 methylation is responsible for suppressing the aberrant transcription of REs in response to anti-androgen treatment. Further, overexpression of the terminal H3K9me3 writers lead to the suppression of REs whereas pharmacological or genetic inhibition of H3K9 trimethylation writers and readers restored REs expression, abrogating resistance to anti-androgen. Moreover, elevated expression of terminal H3K9me3 writers is associated with poor outcomes in patients subjected to hormonal therapy. Interestingly, we have observed that inhibition of double-stranded RNA-specific adenosine deaminase (ADAR1) leads to accumulation of dsRNA and modulates GR expression in PCa cells. Taken together, our study highlights the role of H3K9 trimethylation in mediating resistance to anti-androgen therapy in prostate cancer. Notably, members of the H3K9 trimethylation machinery could potentially serve as therapeutic targets and combinatorial approaches targeting epigenetic regulatory enzymes as well as androgen signaling axis could be a promising strategy for overcoming drug resistance and immune evasion in prostate cancer.
Citation Format: Ritika Tiwari, Mehdi Baratchian, Michael Berk, Jianneng Li, Amy Guerinot, Vladimir Makarov, Timothy A. Chan, Abhishek A. Chakraborty, Nima Sharifi. Epigenetic regulation by H3K9 methylation enables resistance to anti-androgen therapy in prostate cancer. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Epigenomics; 2022 Oct 6-8; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_2):Abstract nr A019.
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Affiliation(s)
- Ritika Tiwari
- 1Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH,
| | - Mehdi Baratchian
- 1Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH,
| | - Michael Berk
- 1Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH,
| | - Jianneng Li
- 1Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH,
| | - Amy Guerinot
- 1Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH,
| | - Vladimir Makarov
- 2Center for Immunotherapy and Precision Immuno-Oncology, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Timothy A. Chan
- 2Center for Immunotherapy and Precision Immuno-Oncology, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Abhishek A. Chakraborty
- 1Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH,
| | - Nima Sharifi
- 1Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH,
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Baratchian M, Tiwari R, Khalighi S, Chakravarthy A, Yuan W, Berk M, Li J, Guerinot A, de Bono J, Makarov V, Chan TA, Silverman RH, Stark GR, Varadan V, De Carvalho DD, Chakraborty AA, Sharifi N. H3K9 methylation drives resistance to androgen receptor-antagonist therapy in prostate cancer. Proc Natl Acad Sci U S A 2022; 119:e2114324119. [PMID: 35584120 PMCID: PMC9173765 DOI: 10.1073/pnas.2114324119] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 03/25/2022] [Indexed: 01/11/2023] Open
Abstract
Antiandrogen strategies remain the prostate cancer treatment backbone, but drug resistance develops. We show that androgen blockade in prostate cancer leads to derepression of retroelements (REs) followed by a double-stranded RNA (dsRNA)-stimulated interferon response that blocks tumor growth. A forward genetic approach identified H3K9 trimethylation (H3K9me3) as an essential epigenetic adaptation to antiandrogens, which enabled transcriptional silencing of REs that otherwise stimulate interferon signaling and glucocorticoid receptor expression. Elevated expression of terminal H3K9me3 writers was associated with poor patient hormonal therapy outcomes. Forced expression of H3K9me3 writers conferred resistance, whereas inhibiting H3K9-trimethylation writers and readers restored RE expression, blocking antiandrogen resistance. Our work reveals a drug resistance axis that integrates multiple cellular signaling elements and identifies potential pharmacologic vulnerabilities.
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Affiliation(s)
- Mehdi Baratchian
- Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Ritika Tiwari
- Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Sirvan Khalighi
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106
| | - Ankur Chakravarthy
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada
| | - Wei Yuan
- Division of Clinical Studies, The Institute of Cancer Research and Royal Marsden Hospital, London SM2 5NG, United Kingdom
| | - Michael Berk
- Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Jianneng Li
- Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Amy Guerinot
- Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Johann de Bono
- Division of Clinical Studies, The Institute of Cancer Research and Royal Marsden Hospital, London SM2 5NG, United Kingdom
| | - Vladimir Makarov
- Center for Immunotherapy and Precision Immuno-Oncology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Timothy A. Chan
- Center for Immunotherapy and Precision Immuno-Oncology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Robert H. Silverman
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - George R. Stark
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Vinay Varadan
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106
| | - Daniel D. De Carvalho
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Abhishek A. Chakraborty
- Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Nima Sharifi
- Genitourinary Malignancies Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Hematology and Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Urology, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH 44125
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