Tanshinone IIA inhibits proliferation and activates apoptosis in C4-1 cervical carcinoma cells in vitro

Abstract

Tanshinone IIA (Tan IIA) is a natural product that has been identified to have anti-proliferative properties against cervical cancer. The study was designed to investigate the anti-tumor effects of Tan IIA at different concentrations on the proliferation and apoptosis of human cervical carcinoma C4-1 cells. Human cervical carcinoma C4-1 cells were treated with different doses of Tan IIA, and MTT assay was performed to determine effects on cell viability. Flow cytometry was used to detect apoptosis and Western blot analysis was carried out to determine alterations in the expression of key proteins. Tan IIA treatment (0.5, 1.0, 2.0, and 5.0 mg/mL) significantly inhibited the growth of C4-1 cells in a time- and dose-dependent manner. Significant differences were observed in the growth inhibition rate between Tan IIA group and the control group (0.5-1.0 mg/L Group: p < 0.05; 2.0–5.0 mg/L Group: p < 0.01). Flow cytometry showed that C4-1 cells became apoptotic after treatment with Tan IIA. In the control group, the apoptosis rate of C4-1 cells was 2.56 ± 0.21% whilst in the Tan IIA-treated groups, different concentrations markedly increased the rate of apoptosis (1.0 mg/L group, 7.9 ± 0.43% [p < 0.05]; 2.0 g/L group, 10.2 ± 0.42%; 5.0 mg/L, 20.44 ± 1.24% [p < 0.01]; except 0.5 mg/L group, 5.8 ± 0.32% [p > 0.05]). Western blot assays indicated that the Tan IIA decreased Bcl-2, HPV 16 E6 and E7 protein levels, but elevated Bax and cleaved-Caspase-3 expression in cells. Tan IIA may inhibit the proliferation and induce the apoptosis of C4-1 cells in a concentration-dependent manner.