Omega-3 PUFAs induce apoptosis of gastric cancer cells via ADORA1

Omega-3 polyunsaturated fatty acids (Omega-3 PUFAs), including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have been suggested to have anti-cancer effects by epidemiological and clinical studies. However, their underlying anti-cancer mechanisms are still unclear. In this study, we examined the influence of two Omega-3 PUFAs (DHA and EPA) on the proliferation and apoptosis of gastric cancer (GC) cells, and found that DHA and EPA reduced the viability of GC cells and induced apoptosis by activating caspase-3. Moreover, we screened the expression profile of apoptosis-related genes in GC cells upon the treatment of DHA and/or EPA, and discovered that ADORA1, one subtype of adenosine receptor functionally involved in cell death, was up-regulated in response to DHA and EPA. Importantly, when GC cells were treated with a selective ADORA1 antagonist, DPCPX, the DHA/EPA-induced apoptosis was substantially reduced. Taken together, our results suggest that the anti-cancer effect of Omega-3 PUFAs on gastric cancer is at least partly dependent on activating the ADORA1-mediated apoptosis pathway.