Apoptosis is induced by docosahexaenoic acid in breast cancer cells via death receptor and mitochondria-mediated pathways.

In the present study, the antitumor effect of n‑3 fatty acid was evaluated, and the effect of docosahexaenoic acid (DHA) on the induction of apoptosis and its underlying mechanism were examined. Flow cytometry and western blot analysis were performed to analyze apoptosis and the expression of protein factors in human breast cancer cells. The data revealed that DHA inhibited the viability of MCF‑7 breast cancer cells in vitro, and promoted cell death by the induction of apoptosis. DHA decreased the expression of B‑cell lymphoma 2 (Bcl‑2), whereas the expression of Bcl‑2‑associated X protein was increased. DHA was also shown to promote the release of Smac/Diablo and cytochrome c from the mitochondria. DHA increased the levels of cleaved caspase‑8, ‑9 and ‑3. Additionally, the protein expression of tumor necrosis factor‑related apoptosis‑inducing ligand, death receptor 4 and Fas were increased following DHA treatment. In conclusion, DHA caused apoptosis of the human breast cancer cells in vitro through the death receptor and mitochondria‑mediated pathways. The results of this study encourage further investigation of the effect of fish oil on the prevention and treatment of human breast cancer.