Effect of vitamin K3 on apoptosis induced by androgen-independent prostate cancer cell PC-3M

AIM: To study the effect of vitamin K₃ (VK₃) on the induction of apoptosis in androgen-independent prostate cancer cell PC-3M in vitro.METHODS: Cell viability was estimated by MTT assay. AO/EB staining was performed to detect apoptotic cells. Apoptosis and the changes of cell cycle were detected by flow cytometry. NAC was used to observe the effect of growth inhibition by VK₃. RT-PCR was used to confirm the changes in gene expression. Levels of intracellular peroxides were estimated by using an oxidation-sensitive fluorescent probe DCFH-DA. RESULTS: PC-3M cells growth was significantly inhibited by VK₃ (≥60 μmol/L, P<0.05). The inhibitory effect was time and dosage dependent. The result of AO/EB staining showed that apoptosis of PC-3M cells were induced by VK₃. A typical subdiploid peak before G₀/G₁ phase was observed after treated for 12 h with VK₃ (60 μmol/L) by flow cytometry. The effect of growth inhibition treated with VK₃ was antagonized by antioxygen NAC (5, 10, 20, 40, 80 μmol/L). An increase in the level of DCF fluorescence after PC-3M cells were treated for 1-2 h with VK₃ was observed. Antioxidase GSH-Px and CAT were run-down after treated with VK₃. CONCLUSION: The results indicate that apoptosis in PC-3M cells is induced through oxidative stress by VK₃.