MALAT1 and prostate carcinoma: In addition, the colony-forming ability of MALAT1-silenced prostate cancer cells was significantly impaired in the presence of olaparib in PARPi-sensitive (22RV1 and LNCaP) as well as PARPi-insensitive (DU145 and PC3) prostate cancer cell lines (Fig. 6C and D; Supplementary Fig. S6), suggesting that MALAT1 depletion could sensitize HR-deficient as well as HR-proficient prostate cancer cells to olaparib.