Effect of ?-3 PUFA and exogenous transmembrane TNF-? on MCF-7 cell apoptosis / 第三军医大学学报

ABSTRACT

Objective To study the apoptosis and its molecular mechanism of MCF-7 cells induced by ?-3 polyunsaturated fatty acid(?-3 PUFA)combined with the product of exogenous transmembrane TNF-?(tmTNF-?) gene.Methods The tmTNF-? eukaryotic expression vector containing the PPRE-tk promoter was transfected into the human breast cancer MCF-7 cells.The effects of ?-3 PUFA and/or exogenous tmTNF-? on the cell proliferation and apoptosis were measured by MTT and DNA ladder assay.The activity of caspase-8 was examined by using special fluorescence substrate,and the expression of caspases(1,8 and 9) were analyzed by RT-PCR and Western blotting.The inhibitor of caspases was used to confirm the function of caspase.Results In 6.0?10~(-5)mol/L ?-3 PUFA-treated MCF-7 cells,only the growth suppression was found.In transfected MCF-7 cells after treated with ?-3 PUFA,not only the proliferation capacity was decreased but the DNA ladder was detectable.The expression changes of caspases(1,8 and 9) and caspase-8 activity were obvious in MCF-7 transfected cells treated with ?-3 PUFA.Growth inhibition and apoptosis induced by ?-3 PUFA and tmTNF-? were partly prevented by the special caspase inhibitor.Conclusion These results suggested that up-regulated expression and activity of caspase might promote MCF7 cells apoptosis induced by ?-3 PUFA and exogenous tmTNF-?,indicating that ?-3 PUFA and exogenous tmTNF-? could cooperate in inhibition of the MCF-7 cell growth and induction of apoptosis.caspase network pathway may play a key role in these processes.