Abiraterone Acetate, in Combination with Apigenin, Attenuates the Survival of Human Castration-Sensitive Prostate Cancer Cells

Background: Abiraterone acetate (AA) is a selective inhibitor of CYP17 alpha-hydroxylase, which is crucial for androgen biosynthesis. Apigenin (Api) is a natural plant-derived flavonoid with potent antiproliferative and anti-migration effects. Objectives: We aimed to investigate the possible role of Api in combination with the androgen receptor inhibitor AA in the treatment of androgen-sensitive human prostate cancer LNCaP cells. Methods: The cells were either exposed to 10 mu M AA, 25 mu M Api, or in combination for 48 hours, then the viability rate was determined by the MTT test, whilst apoptosis and cell cycle phases were assessed by image-based cytometry. The expression of selected mRNA and proteins were evaluated by RT-qPCR and Western blot, respectively. Results: The combination of AA and Api significantly inhibited LNCaP as well as androgen-insensitive PC3 cell survival in a manner more marked than observed with either single treatment. Co-administration of Api with AA triggered apoptosis. This effect was demonstrated by Hoechst staining, and up-regulation of Bax, cytochrome c, caspase -3, and -8 and down-regulation of Bcl-2 expression confirmed the effect. AA and Api each individually arrested the cell cycle in the G1 phase, with dual applications, leading to no further increase in the effect produced. The expression of NF-kappa B p105/p50 and the phosphorylation of AKT markedly decreased after apigenin treatment, with combination treatment leading to a favourable effect in terms of further augmenting the reduction. Conclusion: The co-administration of Api with AA strongly enhanced the efficacy of AA therapy in the treatment of prostate cancer cells. These data suggested that the combination of AA and Api would be a potential chemotherapeutic strategy against prostate cancer.