Development of Olaparib-Resistance Prostate Cancer Cell Lines to Identify Mechanisms Associated with Acquired Resistance

Maxime Cahuzac; Benjamin Péant; Anne-Marie Mes-Masson; Fred Saad

doi:10.3390/cancers14163877

Development of Olaparib-Resistance Prostate Cancer Cell Lines to Identify Mechanisms Associated with Acquired Resistance

Cancers (Basel). 2022 Aug 11;14(16):3877. doi: 10.3390/cancers14163877.

Authors

Maxime Cahuzac^{1

2}, Benjamin Péant^{1

2}, Anne-Marie Mes-Masson^{1

2

3}, Fred Saad^{1

2

4}

Affiliations

¹ Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC H2X 0A9, Canada.
² Institut du Cancer de Montréal, Montreal, QC H2X0A9, Canada.
³ Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada.
⁴ Department of Surgery, Université de Montréal, Montreal, QC H3T 1J4, Canada.

Abstract

Background: Poly (ADP-ribose) polymerase inhibitors (PARPi) were initially deployed to target breast and ovarian tumors with mutations in DNA damage response genes. Recently, PARPi have been shown to be beneficial in the treatment of prostate cancer (PC) patients having exhausted conventional therapeutics. Despite demonstrating promising response rates, all patients treated with PARPi eventually develop resistance. However, PARPi resistance in PC is not well understood, and further studies are required to understand PARPi resistance in PC to propose strategies to circumvent resistance.

Methods: Starting from well-established olaparib-sensitive PC cell lines (LNCaP, C4-2B and DU145), we derived olaparib-resistant (OR) PC cell lines and performed a microarray analysis.

Results: The olaparib IC50 values of OR cell lines increased significantly as compared to the parental cell lines. Gene expression analyses revealed that different pathways, including DNA repair, cell cycle regulation and autophagy, were affected by acquired resistance. A total of 195 and 87 genes were significantly upregulated and downregulated, respectively, in all three OR cell lines compared to their parental counterparts. Among these genes, we selected BRCC3, ROCK2 and ATG2B for validation. We showed that ROCK2 expression, basal autophagy and homologous recombination (HR) efficiency were increased in all OR cell lines.

Conclusions: Our study provides a new in vitro model to study PARPi resistance in PC and suggests new possible targets to reverse resistance and prolong the benefits of PARPi treatment.

Keywords: DNA repair; PARP; autophagy; prostate cancer; resistance.

Grants and funding

This work was supported by the Raymond Garneau Chair in Prostate Cancer Research of the Université de Montréal (F.S.) and by research grants from the Canadian Urological Association. M.C. received studentships from Canderel/ICM and the Département de biologie moléculaire de l’Université de Montréal.