title: Involvement of autophagy inhibition inBrucea javanicaoil emulsion-induced colon cancer cell death.
abstract: Brucea javanicaoil emulsion (BJOE), the petroleum ether extract ofB. javanicaemulsified by phospholipid, is widely used in China as an anticancer agent. The extracts fromB. javanicainduce cancer cell death by various mechanisms; however, it is not known whether these mechanisms involve autophagy, which is an important process in cancer development and treatment. Thus, the current study aimed to investigate whether BJOE modulates autophagy in HCT116 human colon cancer cells and whether modulation of autophagy is an anticancer mechanism of BJOE. Immunoblotting was employed to analyze the protein expression levels of microtubule-associated protein light-chain 3 (LC3), a specific protein marker of autophagy, in HCT116 cancer cells following exposure to BJOE. The apoptosis rate of the HCT116 cancer cells was detected by performing an Annexin V-fluorescein isothiocyanate/propidium iodide assay. According to the effect of BJOE administration on autophagy in the HCT116 cancer cells (induction or suppression), a functionally opposite agent (autophagy suppressor or inducer) was applied to counteract this effect, and the apoptosis rate of the cancer cells was detected again. The role of autophagy (pro-survival or pro-death) was demonstrated by comparing the rates of apoptotic cancer cells prior to and following the counteraction. The results revealed that BJOE suppressed the protein expression levels of LC3, including the LC3-I and LC3-II forms, and induced apoptosis in the HCT116 cancer cells with a high level of basal LC3. The apoptosis-inducing activity of BJOE was significantly attenuated when autophagy was induced by the administration of trehalose, an autophagy inducer. The data indicates that autophagy inhibition is involved in BJOE-induced cancer cell death, and that this inhibition may be a potential anticancer mechanism of BJOE.
authors: State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China ; Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China.
authors: Zheng
authors: Z
authors: Yan
authors: State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China ; VIP Region, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China.
authors: Bei
authors: B
authors: Zhang
authors: State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China ; VIP Region, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China.
authors: Yuanyuan
authors: Y
authors: Huang
authors: State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China ; VIP Region, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China.
authors: Huijuan
authors: H
authors: Qiu
authors: State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China ; VIP Region, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China.
authors: Ping
authors: P
authors: Chen
authors: State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China ; VIP Region, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China.
authors: Gui-Fang
authors: GF
authors: Guo
keywords: Brucea javanica oil emulsion; apoptosis; autophagy; colon cancer; light chain 3