Silibinin Induces Apoptosis and G2/M Cell Cycle Arrest in Human Ovarian Cancer SKOV-3 Cell Line

Abstract

Background: Silibinin, an herbal polyphenolic flavonolignan, has antioxidant and anticancer properties. Objectives: This study aimed to evaluate some cellular and molecular effects of silibinin on the human ovarian cancer SKOV-3 cell line. Methods: For cytotoxicity investigations of silibinin, MTT assay was used at 24, 48, and 72 hours. Apoptosis and cell cycle were studied by flow cytometry. The effect of silibinin on mRNA expression of B-cell lymphoma 2 (Bcl-2), cyclin E, and S-phase kinase-associated protein 2 (SKP2) was determined by Quantitative reverse transcription polymerase chain reaction (QRT-PCR). Results: Silibinin administration in lower concentrations (12.5 and 25 µg/mL) did not lead to significant (P < 0.05) changes in cell viability and even slightly increased cell growth after 72 hours. However, silibinin in higher concentrations (≥ 50µg/mL) inhibited SKOV-3 cell proliferation in a dose- and time-dependent manner. The mode of cell growth inhibition was apoptosis induction and G2/M cell cycle arrest. Silibinin caused down-regulation of the anti-apoptotic gene, namely Bcl-2. Additionally, silibinin resulted in down-regulation of the major genes in the cell cycle, including cyclin E and SKP2. Conclusions: Overall, this study confirmed the ability of silibinin to suppress ovarian cancer progression through the induction of apoptosis and inhibition of G2/M phase transition. Silibinin may be considered an efficient and safe herbal medication for ovarian cancer.