Study On Autophagy Induced By Valproic Acid In Prostate Cancer PC-3 Cell And Its Mechanisms

BackgroundProstate cancer is the most frequently diagnosed cancer and the second Leading cause of cancer death in the United States.Even in countries with low rates of Prostate cancer incidence,such as China,the incidence appears to be rising significantly.Howev-er,the primary treatment for Prostate cancer are surgery and radiation,either of which can result in treatment failure.When primary treatment fails,no long-term effective therapy exists for the disease. In recent years,the Histone Deacetylase inhibitor(HDA CI)that inhibit proliferation and Induce differentiation and/or apoptosis of tumor cells in culture and in animal models have been identified. The anti-epileptic drug Valproic acid (VPA)is also under trial as an anti-cancer agent due to its HDACI properties.The research on autophagy induced by Valproic acid in Prostate cancer cells are rare. So,we tried to observe the autophagy of the Prostate cancer PC-3 cell line,induced by Valproic acid and explore its possible mechanisms.ObjectiveTo observe the autophagy of the Prostate cancer cell line PC-3 induced by Valproic acid and explore the possible mechanisms.Materials and MethodsProstate cancer cell line PC-3 was cultured with 5mmol/L Valproic acid acid in 96-well flat-bottomed microtiter plates for 24h,48h,72h.CCK-8 was used to examine the proliferation rate. PC-3 cells were plated in six-well plates and allowed to attach overnight. The cells were then treated with VPA of 5.0 mmol/L for 24h,48h,72 h.Autophagosome and autolysosomes was observed under transmission electronic microscopy.PC-3 cells were grown in 6-well flat-bottomed microtiter plates to attach by overnight incubation.Then PC-3 cells were cultured in medium with VPA of 5.0 mmol/L for 48h,72h and 96h.cells were cultured with anti-LC3 antibody for 4℃overnight. Cells were then washed with PBS three times and incubated with goat anti-rabbit antibody with Annexin V-FITC for 30 min in dark at room emperature.The intensity of autophagy was analysed by immunofluorescence.The expression levels of LC3-Ⅱand p-Akt were measured by Western-blotting.ResultsThe viability of Human Prostate cancer PC-3 cells treated with acute VPA is unchanged significantly.Autophagosomes and autolysosomes were observed in VPA-treated Human Prostate cancer PC-3 cells under transmission electronic microsc-opy.The intensity of autophagy was time-dependent. The expression levels of related protein LC3-Ⅱwere elevated,while p-Akt were declined following VPA treatment in human Prostate cancer PC-3 cell line.ConclusionsIn summary,our study provides evidence that VPA can induce autophagy in Human Prostate cancer PC-3 cell line.The mechanism may be related to the disruption of Akt/mTOR signaling pathway.