Induction of apoptosis and lipogenesis in human preadipocyte cell line by n-3 PUFAs

We examined the effect of n-3 PUFAs (polyunsaturated fatty acids) on the growth and maturation of human preadipocyte cell line AML-I. On day 3 of the culture, n-3 fatty acids such as DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), but not n-6 fatty acid LA (linoleic acid), induced growth arrest accompanied by the appearance of characteristics of apoptosis in AML-I cells at concentrations between 250 and 500 μM by Annexin V-FITC staining. In Western blotting analysis, the loss of NF-κB, Bcl-2 and p-Akt and the accumulation of Bad and Akt were observed in the cytoplasmic protein from the EPA-treated cells. Exposure of AML-I to EPA or DHA increased the cytoplasmic lipid accumulation compared with the vehicle-treated cells in a time-dependent manner during 4 and 6 days culture period by Oil Red O staining. The expression of FAS (fatty acid synthase) and PPAR-γ (peroxisome proliferator-activated receptor-γ) were increased in EPA-treated cells. These results suggest that EPA and DHA promote differentiation, inhibit proliferation and induce apoptosis in preadipocyte cell line AML-I.