The side effects associated with flutamide as a first-line drug treating prostate cancer, including hepatotoxicity, the aim of this research was to use melatonin as an anticancer candidate to reduce the dose of flutamide and reduce its side effects. We evaluated the effect of melatonin, flutamide, and melatonin-flutamide combination therapy in LNCaP, DU145, and PC3 cell lines. The assessment includes Hoechst dye staining, scratch-wound assay, colony formation assay, flow cytometric analysis of apoptosis and DNA cell cycle, real-time PCR (BAX [BCL2 Associated X]/B-cell lymphoma-2 [BCL2], E-cadherin, Zinc finger protein SNAI2 [SNAIL], Hypoxia Inducible Factor 1 Subunit Alpha [HIF1α], Vascular Endothelial Growth Factor C [VEGFC], and kallikrein-related peptidase 3 [KLK3] genes). To determine Half maximal inhibitory concentration (IC50) levels, cell lines were exposed to different concentrations of the drugs. Our data indicated that IC50 values for melatonin (75 µM) and three cell lines and flutamide (12 and 10 µM) for PC3 and LNCaP/DU145, respectively, with 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide were approved by flow cytometry in a dose and time-dependent manner which was as a consequence of cell cycle arrest at G0/G1 phase. Due to the efficacy of melatonin in combination with flutamide, we used 75 µM melatonin, and 5 µM flutamide instead of 12 µM in DU145, and 6 µM in PC3 and LNCaP, respectively. The combination of melatonin and flutamide significantly upregulated the expression of BAX/BCL2 ratio in all three cell lines (p < 0.0001) and downregulated the expression of KLK3 (p < 0.01), HIF1α (p < 0.01), VEGFC (p < 0.001), and epithelial-mesenchymal transition pathway genes in PC3 and LNCaP (p < 0.01). Melatonin in combination with flutamide reduced its dose and increased the sensitivity of prostate cancer cells to treatment.
Keywords: cancer cell line; flutamide; melatonin; prostate cancer.