Effect Of Conjugated Linoleic Acid And Docosahexaenic Acid On Apoptosis Of Endometrial Cancer Cells

Numerous studies have shown that polyunsaturated fatty acids (PUFA) can inhibit cancer cells growth and induce apoptosis in vitro and vivo. Endometrial cancer (EC) is one of the most common gynecologic malignancies and its incidence has recently increased. There are no reports on the inhibition of endometrial cancer with UFA. The aim of the present study was to investigate effects of PUFA, including linoleic acid(LA), cis9, trans11-conjugated linoleic acid (c9, t11-CLA), trans10, cis12-conjugated linoleic acid (t10, c12-CLA) and docosahexaenoic acid (DHA), on apoptosis of RL95-2human endometrial cancer cells and to assess apoptotic mechanism in RL95-2cells.The effects of cell viability of RL95-2cell lines with different concentrations and various treatment periods were investigated by MTT assay. The results showed no significant inhibition effect was in RL95-2cells with LA and t10, c12-CLA. c9, tll-CLA and DHA inhibited RL95-2cells growth in dose-dependent and time-dependent. The morphological changes of RL95-2cell apoptosis was observed by Fluorescence Microscope and the ratio of apoptosis were determined by flow cytometry. After incubation for48h, the apoptotic rates of RL95-2with40μmol/L、80μmol/L and160μmol/L c9,t11-CLA and DHA respectively were more than70%. On this basis, the apoptotic mechanism of two kinds of fatty acids inducing apoptosis in RL95-2cell lines was further investigated. The expression of apoptosis associated protein Bax/Bcl-2, p-ERa/ERa, p-Akt/Akt and caspase-3by western blot. The results showed that40μmol/L c9, tll-CLA induced apoptosis by increasing the ratio between Bax and Bcl-2. When the concentration reached80μmol/L, c9, tll-CLA influenced the expression level of Bax and inhibite the activity of ERa, meanwhile, regulated the expression of caspase-3. The apoptosis mechanism of40μmol/L DHA inducing RL95-2was consistent with80μmol/L c9, tll-CLA. Howere,80μmol/L DHA not only upregulated the protein level of Bax and downregulated the ratio of between p-ERa and ERa, but also significantly inhibited the expression of p-Akt. DHA also increased the expression of caspase-3.This study suggested the apoptosis-promoting effect of c9, tll-CLA and DHA on endometrial cancer RL95-2cells and also demonstrated the apoptosis induced by c9, t11-CLA was associated with the apoptosis proteins Bcl-2family changes, and inhibition of ERa activity. In addition, apoptotic effect of DHA was correlative with Bax/Bcl-2, p-ERa/ERα and p-Akt/Akt. These paper provided effective evidences for PUFA as functional food biotherapy in tumors.