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Tolkach Y, Kremer A, Lotz G, Schmid M, Mayr T, Förster S, Garbe S, Hosni S, Cronauer MV, Kocsmár I, Kocsmár É, Riesz P, Alajati A, Ritter M, Ellinger J, Ohlmann CH, Kristiansen G. Androgen Receptor Splice Variants Contribute to the Upregulation of DNA Repair in Prostate Cancer. Cancers (Basel) 2022; 14:4441. [PMID: 36139600 PMCID: PMC9496991 DOI: 10.3390/cancers14184441] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Canonical androgen receptor (AR) signaling regulates a network of DNA repair genes in prostate cancer (PCA). Experimental and clinical evidence indicates that androgen deprivation not only suppresses DNA repair activity but is often synthetically lethal in combination with PARP inhibition. The present study aimed to elucidate the impact of AR splice variants (AR-Vs), occurring in advanced or late-stage PCA, on DNA repair machinery. METHODS Two hundred and seventy-three tissue samples were analyzed, including primary hormone-naïve PCA, primary metastases, hormone-sensitive PCA on androgen deprivation therapy (ADT) and castration refractory PCA (CRPC group). The transcript levels of the target genes were profiled using the nCounter platform. Experimental support for the findings was gained in AR/AR-V7-expressing LNCaP cells subjected to ionizing radiation. RESULTS AR-Vs were present in half of hormone-sensitive PCAs on androgen deprivation therapy (ADT) and two-thirds of CRPC samples. The presence of AR-Vs is highly correlated with increased activity in the AR pathway and DNA repair gene expression. In AR-V-expressing CRPC, the DNA repair score increased by 2.5-fold as compared to AR-V-negative samples. Enhanced DNA repair and the deregulation of DNA repair genes by AR-V7 supported the clinical data in a cell line model. CONCLUSIONS The expression of AR splice variants such as AR-V7 in PCA patients following ADT might be a reason for reduced or absent therapy effects in patients on additional PARP inhibition due to the modulation of DNA repair gene expression. Consequently, AR-Vs should be further studied as predictive biomarkers for therapy response in this setting.
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Affiliation(s)
- Yuri Tolkach
- Institute of Pathology, University Hospital Bonn, 53127 Bonn, Germany
- Institute of Pathology, University Hospital Cologne, 50937 Cologne, Germany
| | - Anika Kremer
- Institute of Pathology, University Hospital Bonn, 53127 Bonn, Germany
| | - Gábor Lotz
- Department of Pathology, Forensic and Insurance Medicine, Semmelweis University, 1085 Budapest, Hungary
| | - Matthias Schmid
- Department of Medical Biometry, Informatics, and Epidemiology (IMBIE), University Hospital Bonn, 53127 Bonn, Germany
| | - Thomas Mayr
- Institute of Pathology, University Hospital Bonn, 53127 Bonn, Germany
| | - Sarah Förster
- Institute of Pathology, University Hospital Bonn, 53127 Bonn, Germany
| | - Stephan Garbe
- Department of Radiation Oncology, University Hospital Bonn, 53127 Bonn, Germany
| | - Sana Hosni
- Clinic of Urology, University Hospital Bonn, 53127 Bonn, Germany
| | | | - Ildikó Kocsmár
- Department of Urology, Semmelweis University, 1085 Budapest, Hungary
| | - Éva Kocsmár
- Department of Pathology, Forensic and Insurance Medicine, Semmelweis University, 1085 Budapest, Hungary
| | - Péter Riesz
- Department of Urology, Semmelweis University, 1085 Budapest, Hungary
| | - Abdullah Alajati
- Clinic of Urology, University Hospital Bonn, 53127 Bonn, Germany
| | - Manuel Ritter
- Clinic of Urology, University Hospital Bonn, 53127 Bonn, Germany
| | - Jörg Ellinger
- Clinic of Urology, University Hospital Bonn, 53127 Bonn, Germany
| | | | - Glen Kristiansen
- Institute of Pathology, University Hospital Bonn, 53127 Bonn, Germany
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