Effect of Shikonin on cell cycle and apoptosis of ovarian cancer HO-8910 cells by regulating PI3K/Akt signaling pathway

Objective To investigate the effect of Shikonin on cell cycle and inducted apoptosis of human ovarian cancer HO-8910 cells and its role in the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway. Methods The ovarian cancer HO-8910 cells in the logarithmic growth phase were treated with various doses of Shikonin. CCK-8 assay was used to determine the inhibition rate of cell proliferation. The half-inhibitory concentration (IC50) was calculated and the working concentration of Shikonin was thereby screened for the subsequent experiments. The effect of Shikonin on the HO-8910 cell cycle was measured by flow cytometry. The effect of Shikonin on the apoptosis of HO-8910 cells was detected by Annexin V-FITC/PI double staining. Western blotting was used to examine the protein expression of Cyclin D1, Bcl-2 related X gene (Bax) , cleaved cysteine-containing Caspase-3, PI3K, AKT, as well as the PI3K/AKT phosphorylation levels. Results Various doses of Shikonin exhibited different levels of inhibition on HO-8910 cells proliferation. The Shikonin concentrations selected according to IC50 for subsequent experiments were 5 μg/ml and 10 μg/ml. Shikonin was able to arrest the cell cycle at G0/G1 phase, induce cell apoptosis, inhibit Cyclin D1 protein expression, promote Bax and cleaved caspase-3 protein expression, and inhibit PI3K/AKT signaling pathway activation. Conclusion Shikonin may suppress the cell cycling and induce apoptosis of ovarian cancer HO-8910 cells. Such anti-tumor mechanism may be related to inhibition of PI3K/AKT signaling pathway activation. Key words: Ovarian Neoplasms; Cell Cycle; Apoptosis; Cell cycle; Apoptosis; shikonin; PI3K/AKT signaling pathway