Mp05-11 Pink1 Signaling Confers Olaparib Resistance by Activating Mitochondrial Function in Advanced Prostate Cancer Cells

You have accessJournal of UrologyProstate Cancer: Basic Research & Pathophysiology I (MP05)1 May 2024MP05-11 PINK1 SIGNALING CONFERS OLAPARIB RESISTANCE BY ACTIVATING MITOCHONDRIAL FUNCTION IN ADVANCED PROSTATE CANCER CELLS Allen Gao, Zachary Schaaf, Shu Ning, Amy Leslie, Masuda Sharifi, Alan Lombard, and Wei Lou Allen GaoAllen Gao , Zachary SchaafZachary Schaaf , Shu NingShu Ning , Amy LeslieAmy Leslie , Masuda SharifiMasuda Sharifi , Alan LombardAlan Lombard , and Wei LouWei Lou View All Author Informationhttps://doi.org/10.1097/01.JU.0001008740.27639.cc.11AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The PARP inhibitor (PARPi) Olaparib has shown great efficacy in treating castration resistant prostate cancer (CRPC) patients with deficiency in DNA damage response (DDR) genes. Despite general improvements in prognosis, some patients develop therapeutic resistance to Olaparib therapy. We developed an Olaparib resistant CRPC model (OlapR) to uncover potential mechanisms of therapeutic resistance as well as vulnerabilities associated with the resistant phenotype. METHODS: OlapR cells were generated from parental C4-2B cells with chronic exposure to Olaparib. RNA sequencing and gene expression analysis was performed on both lines. Mitochondrial Stress Tests using Seahorse XF Analyzer, MitoTracker staining, and ROS quantification assays were performed on both cell lines. The effects of ablated PINK1 expression on sensitivity to Olaparib was also examined in OlapR cells. RESULTS: Pathway and gene enrichment analysis revealed a significant enrichment of pathways related to mitochondrial activity (Oxidative Phosphorylation) in OlapR cells. We further demonstrate higher levels of basal Oxygen Consumption Rate, ATP production, Spare Respiratory Capacity, Maximal Respiration, and Coupling efficiency in OlapR cells. OlapR cells also display around twice as much active mitochondria compared to the treatment-naïve parental C4-2B. Interestingly, higher non-mitochondrial oxygen consumption was also noted in OlapR cells, along with increased reactive oxidative species (ROS). Among genes associated with mitochondrial activity, PTEN-induced kinase 1 (PINK1) expression is significantly upregulated in OlapR cells. PINK1 acts as a master regulator of mitochondria-specific autophagy (mitophagy) through clearance of damaged mitochondria. Through knock-down (KD) of PINK1, recognition and subsequent clearance of damaged mitochondria is limited. This results in accumulation of dysfunctional mitochondria as well as increased cellular ROS. Furthermore, PINK1 KD limited OlapR cell growth, and sensitized OlapR cells to Olaparib supplementation. CONCLUSIONS: These findings suggest that the activation of PINK1 signaling enhances mitochondrial function in Olaparib-resistant CRPC cells. The inhibition of PINK1 leads to the accumulation of damaged mitochondria that produce ROS, which in turn results in cell death and enhanced sensitivity to Olaparib. Source of Funding: CA 225836 (A.C.G), CA250082 (A.C.G), CA271327 (A.C.G), DOD PC180180 (A.C.G), and the U.S. Department of Veterans Affairs, Office of Research & Development BL&D grant number I01BX004036 (A.C.G), BLR&D Research Career Scientist Award IK6BX005222 (A.C.G). A.C.G is also a Senior Research Career Scientist at VA Northern California Health Care System, Mather, California © 2024 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 211Issue 5SMay 2024Page: e47 Advertisement Copyright & Permissions© 2024 by American Urological Association Education and Research, Inc.Metrics Author Information Allen Gao More articles by this author Zachary Schaaf More articles by this author Shu Ning More articles by this author Amy Leslie More articles by this author Masuda Sharifi More articles by this author Alan Lombard More articles by this author Wei Lou More articles by this author Expand All Advertisement PDF downloadLoading ...