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Luk ISU, Shrestha R, Xue H, Wang Y, Zhang F, Lin D, Haegert A, Wu R, Dong X, Collins CC, Zoubeidi A, Gleave ME, Gout PW, Wang Y. BIRC6 Targeting as Potential Therapy for Advanced, Enzalutamide-Resistant Prostate Cancer. Clin Cancer Res 2016; 23:1542-1551. [PMID: 27663589 DOI: 10.1158/1078-0432.ccr-16-0718] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 08/11/2016] [Accepted: 09/05/2016] [Indexed: 11/16/2022]
Abstract
Purpose: Enzalutamide resistance has emerged as a major problem in the management of castration-resistant prostate cancer (CRPC). Research on therapy resistance of CRPCs has primarily focused on the androgen receptor pathway. In contrast, there is limited information on antiapoptotic mechanisms that may facilitate the treatment resistance. The inhibitor of apoptosis proteins (IAP) family is well recognized for its role in promoting treatment resistance of cancers by inhibiting drug-induced apoptosis. Here, we examined whether BIRC6, an IAP family member, has a role in enzalutamide resistance of CRPCs and could provide a therapeutic target for enzalutamide-resistant CRPC.Experimental Design: Use of enzalutamide-resistant CRPC models: (i) the transplantable, first high-fidelity LTL-313BR patient-derived enzalutamide-resistant CRPC tissue xenograft line showing primary enzalutamide resistance, (ii) MR42D and MR49F CRPC cells/xenografts showing acquired enzalutamide resistance. Specific BIRC6 downregulation in these models was produced using a BIRC6-targeting antisense oligonucleotide (ASO-6w2). Gene expression was determined by qRT-PCR and gene expression profiling. Molecular pathways associated with growth inhibition were assessed via gene enrichment analysis.Results: Of eight IAPs examined, BIRC6 was the only one showing elevated expression in both enzalutamide-resistant CRPC models. Treatment with ASO-6w2 markedly suppressed growth of LTL-313BR xenografts and increased tumor apoptosis without inducing major host toxicity. Pathway enrichment analysis indicated that GPCR and matrisome signaling were the most significantly altered pathways. Furthermore, ASO-6w2 inhibited expression of prosurvival genes that were upregulated in the LTL-313BR line.Conclusions:BIRC6 targeting inhibited the growth of enzalutamide-resistant CRPC models and may represent a new option for clinical treatment of advanced, enzalutamide-resistant prostate cancer. Clin Cancer Res; 23(6); 1542-51. ©2016 AACR.
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Affiliation(s)
- Iris Sze Ue Luk
- Vancouver Prostate Centre, Vancouver, British Columbia, Canada.,Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Raunak Shrestha
- Vancouver Prostate Centre, Vancouver, British Columbia, Canada
| | - Hui Xue
- Vancouver Prostate Centre, Vancouver, British Columbia, Canada.,Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Yuwei Wang
- Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Fang Zhang
- Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Dong Lin
- Vancouver Prostate Centre, Vancouver, British Columbia, Canada.,Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Anne Haegert
- Vancouver Prostate Centre, Vancouver, British Columbia, Canada
| | - Rebecca Wu
- Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Xin Dong
- Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Colin C Collins
- Vancouver Prostate Centre, Vancouver, British Columbia, Canada.,Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amina Zoubeidi
- Vancouver Prostate Centre, Vancouver, British Columbia, Canada.,Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Martin E Gleave
- Vancouver Prostate Centre, Vancouver, British Columbia, Canada.,Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Peter W Gout
- Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Yuzhuo Wang
- Vancouver Prostate Centre, Vancouver, British Columbia, Canada. .,Department of Experimental Therapeutics, BC Cancer Agency, Vancouver, British Columbia, Canada.,Department of Urologic Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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