Inhibitory effect and mechanism of cucurbitacin E on the proliferation of ovarian cancer cells

Abstract

Background and Objective: Cucurbitacin E (CuE) possesses various biological activities, such as antitumor activity, anti-carcingentic activity, liver protection and enhancing the immunity. This study was to investigate the effects of CuE on the proliferation and apoptosis of ovarian cancer ES-2 cells, and explore the underlying mechanism. Methods: ES-2 cells were treated with different concentrations of CuE for 24, 48, and 72 h, respectively. Cell proliferation was tested by MTT assay. The morphologic changes and apoptosis were observed under Inverted microscope and fluorescent microscope. Cell cycle distribution was evaluated with flow cytometry. The expression of p-STAT3 was determined by Western blot. Results: The proliferation of ES-2 cells was significantly inhibited as the CuE concentration Increased or the time prolonged. When treated with 1 Mmol/L CuE for 24 h, the proportion of ES-2 cells was increased in S phase from (10.55±0.91)% to (16.31 ±4.61)% and in G2/M phase from (18.53±1.43)% to (58.34±5.77)%, while decreased in G1 phase from (73.13±4.70)% to (23.12±5.45)% (P<0.05); marked morphologic changes of cell apoptosis were observed. CuE inhibited the STAT3 phosphorylation in ES-2 cells and the effect was enhanced with dose increasing. Conclusion: CuE can inhibit ES-2 cell proliferation, induce apoptosis and arrest cell cycle, which may be related to the decreased intracellular STAT3 phosphorylation.