The Antiproliferative and Pro-Apoptotic Effects of a Synthetic Omega-3 Epoxyfatty Acid Analogue in Different Human Cancer Cell Lines

Abstract

Objective: To evaluate the anti-cancer effects of C20E in human cell lines representative of cervical (HeLa), liver (HEPG2), lung (A549), prostate (DU145), placental (BeWo) and breast (MDA-MB-468) tumours. Methods and Results: After treatment with C20E, cell proliferation was estimated by mitochondrial MTT reduction, cell viability by ATP production and apoptosis by caspase 3/7 activity. C20E decreased MTT reduction in all cell lines in a concentration-dependent fashion (by 30±4%-76±15% from control at 40 µM, 48 hours of treatment). C20E significantly impaired ATP production to 51±8.4%, 6.1±1.2%, 77.1±5.1%, 70.3±7.9% relative to control (40 µM, 48 hours) in A549 lung carcinoma, BeWo placental choriocarcinoma, DU145 prostate carcinoma and HeLa cervical adenocarcinoma cells, respectively. C20E did not significantly impair ATP production in HEPG2 hepatocellular adenocarcinoma and MDA-MB-468 breast adenocarcinoma cells. Similarly, caspase 3/7 activity was increased by 26±4%-49±8% over control. To pursue these findings, cell cycle kinetics were analysed in propidium iodide-stained cells. Treatment with C20E (40 µM, 48 hours) increased the proportion of cells in the G0 and G1 phase whilst decreasing the proportion of cells in the S phase and G2/M phase, except for BeWo placental choriocarcinoma cells. Western immunoblotting for cyclin D1 was undertaken because this protein regulates the G1 to S phase transition, and was down regulated in MDA-MB-231 breast adenocarcinoma cells by C20E. A decrease in cyclin D1 expression at 40 µM in A549, DU145, HeLa, HEPG2 and MDA-MB-468 cancer cell lines occurred after 48 hours of C20E treatment but not in BeWo cells. Conclusion: C20E decreased the viability of multiple cancer cell lines by inhibiting cell cycle progression, likely due to cyclin D1 down-regulation and also increased apoptosis. The responsiveness of A549, DU145 and HeLa cell lines suggests that further testing in lung, prostate and cervical cancer models is warranted.