Zoledronic Acid Enhances the Chemotherapeutic Efficiency of 5-fluorouracil or Flutamide in Prostate Cancer Cells with Modulation of miR-382 and miR-18a Expression

Owing to a lack of appropriate therapeutic regimens, prostate cancer (PC) is a global health concern with a high incidence and mortality rate in elderly men. Combination treatment seems to have the highest clinical benefit and avoids unwanted side effects. The current study focused on the chemotherapeutic efficacy of Zoledronic acid (ZA) in combination with 5-fluorouracil (5-FU) or Flutamide on prostate cancer cells, as well as its effect on apoptosis. The MTT assay was used to determine the cytotoxic effect of Zoledronic acid (ZA), 5-FU, and flutamide on PC-3 and DU-145 cells, as well as the combined therapy of ZA with 5-FU or flutamide. Additionally, immunofluorescence staining analysis was used to assess changes in Bcl-2 and p53 expression. Furthermore, the western blotting method was extensively used to evaluate Bax, caspase 3, and cyclin D1. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) was applied to determine the relative expression of miRNA-382 (miR-382) and miRNA-18a (miR-18a). Instead of (13.47, 8.23, and 9.42 μM) for PC-3 or (38.77, 17.6, and 8.47 μM) for DU145 cells, the combination therapy improved cytotoxicity with doses approximately half of IC50 (6.74, 4.12, and 7.07 μM) in PC-3 and (19.38, 8.8, and 6.33 μM) in DU145 cells for ZA, 5-FU, and flutamide, respectively. When compared to a single therapy, the combination therapy significantly up-regulated the pro-apoptotic Bax, cleaved caspase 3 and p53 levels while down-regulated the cyclin D1 and Bcl-2 expression. In addition, the combination therapy was linked to changes in miR-382 and miR-18a expression. Our findings suggest that combining ZA with 5-FU or flutamide improves chemotherapeutic efficacy against prostate cancer cells, at least in part by encouraging apoptosis and modulating miRNA expression, especially miR-382 and miR-18a.