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Int J Clin Exp Pathol 2013;6(9):1799-1805

Original Article
Growth inhibitory effect of Cucurbitacin E on breast cancer cells

Tian Lan, Linling Wang, Qian Xu, Weiguo Liu, Hongchuan Jin, Weimin Mao, Xian Wang, Xiaojia Wang

Department of Medical Oncology, the key laboratory of Integrated Chinese and Western Medical Oncology in Zhejiang Province, Zhejiang
Cancer Hospital, HangZhou, China 310022; Department of Medical Oncology, Institute of Clinical Science, Sir Runrun Shaw Hospital, Medical
College of Zhejiang University, Hangzhou, China 310003

Received July 5, 2013; Accepted August 3, 2013; Epub August 15, 2013; Published September 1, 2013

Abstract: Objective: Due its inhibitory effects on chemical carcinogenesis and inflammation, Cucurbitacins have been proposed as an effective
agent for the prevention or treatment of human cancers. In this study, we aimed to explore the effect of Cucurbitacin E (CuE) on human breast
cancer cells. Methods: The inhibitory effect of CuE on proliferation of Bcap37 and MDA-MB-231 cells was assessed by MTT assay. The cell
cycle distribution and cell apoptosis were determined by flow cytometry (FCM). The expression of pro-caspase 3, cleaved caspase 3, p21, p27
and the phosphorylation of signaling proteins was detected by Western Blotting. Results: CuE inhibited the growth of human breast cancer
cells in a dose and time-dependent manner. FCM analysis showed that CuE induced G2/M phase arrest and cell apoptosis. CuE treatment
promoted the cleavage of caspase 3 and upregulated p21 and p27. In addition, the phosphorylation of STAT3 but not ERK-1/2 was abrogated
upon CuE treatment. Interestingly, lose-dose CuE significantly enhanced the growth inhibition induced by cisplatin. Conclusions Cucurbitacin E
(CuE) could inhibit the growth of human breast cancer cells in vitro. CuE induced both apoptosis and cell cycle arrest probably through the
inhibition of STAT3 function. Lose-dose CuE significantly enhanced the growth inhibitory effect of cisplatin on breast cancer cells, further
indicating the potential clinical values of CuE for the prevention or treatment of human breast cancer. (IJCEP1307010).

Keywords: Cucurbitacin E, breast cancer, apoptosis

Address correspondence to: Dr. Xian Wang, Department of Medical Oncology, Institute of Clinical Science, Sir Runrun Shaw Hospital, Medical
College of Zhejiang University, Hangzhou, China 310003. E-mail: wangxzju@163.com; Dr. Xiaojia Wang, Department of Medical Oncology, the
Key Laboratory of Integrated Chinese and Western Medical Oncology in Zhejiang Province, Zhejiang Cancer Hospital, HangZhou, China
310022. E-mail: wxiaojia0803@163.com