[Inhibitory effect of cucurbitacin E on the proliferation of ovarian cancer cells and its mechanism].
OBJECTIVE
There are various biological activities of cucurbitacin E (CuE), including antitumor effect, anti-chemical carcino-genesis, liver protection, and enhancement of the immunity, and so on. This study was to investigate the effect of CuE on proliferation inhibition and apoptosis induction of ovarian cancer ES-2 cells, and to explore the 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 number of ES-2 significantly decreased as the concentration of CuE increased or the time prolonged. Flow cytometry analysis showed that the ratio of ES-2 cells treated 1 micromol/L CuE for 24 h increased both in S phase [from (10.55+/-0.91)% to ( 16.31 +/- 4.61) % ] and in G(2)/M phase [from (18.53+/-1.43)% to (58.34 +/- 5.77)%], while decreased in G(1) phase [from (73.13 +/-4.70)% to (23.12 +/- 5.45)%] (P<0.05). The marked morphological changes of cell apoptosis were clearly observed in ES-2 cells treated with CuE. CuE inhibited the STAT3 phosphorylation in ES-2 cell in a dose- dependent manner.


CONCLUSIONS
CuE can inhibit ES-2 proliferation and induce apoptosis and cell cycle arrest, which may be related to the decreased expression of the intracellular STAT3 phosphorylation.
Shan
Xiao-Lei
XL
Department of Clinical Pharmacology, China Medical University, Shenyang, Liaoning 110001, People's Republic of China.
Zhou
Xue-Ying
XY
Yang
Jiao
J
Wang
Yan-Li
YL
Deng
Yi-Hui
YH
Zhang
Mei-Xia
MX
D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology*; D010766:Phosphorylation; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D013997:Time Factors; D014315:Triterpenes / Q000008:administration & dosage / Q000494:pharmacology*
D000972:Antineoplastic Agents, Phytogenic; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D014315:Triterpenes; C102326:cucurbitacin E