Anticancer Effect of Carob Bean Extract on Human Prostate Cancer Cell Lines: Apoptosis Induction and Bax/Bcl-2 Ratio Improvement

Carob (Ceratonia siliqua L.) has been used to cure various diseases in traditional medicine. This plant has also exerted antiproliferative effects on certain cancer types. The present study aimed to determine the effects of carob bean extracts on proliferation and apoptotic genes (Bax, Bcl-2, and P53) and Caspase-3, -8, and -9 expressions of human prostate cancer cell lines. In this in vitro experimental study, human prostate cell lines (LNCaP and PC3) were treated with carob bean extract (0, 50, 100, 200, 400, and 800 μg/ml) for 24, 48, 72, and 96 h. Cell viability was investigated via MTT assay. The genes expression: Bax (pro-apoptotic), Bcl-2 (anti-apoptotic), Caspase-3 (required enzyme for the execution of apoptosis), Caspase-8 (mediator of the extrinsic pathway), and Caspase-9 (mediator of the intrinsic pathway) genes, as well as P53 (tumor suppressor), were assessed using real-time polymerase chain reaction. Moreover, the nitric oxide in culture media was evaluated. Carob bean extract suppressed the proliferation of prostate cancer cells in a time and dose-dependent manner by inducing intrinsic apoptotic pathways and decreasing nitric oxide production (P < 0.01). The obtained results revealed the overexpression of Caspases-3 and -9, P53, and Bax, but reduction in Bcl-2 expression, giving rise to a higher Bax/Bcl-2 ratio (P < 0.05). The carob bean extracts exerted anti-prostate cancer properties via induction of apoptosis. It could be also suggested as a dietary supplement for patients suffering from prostate cancer.