RESUMO
The aim of the present study was to investigate the mechanism of the inhibitory effect of luteolin on the proliferation of breast cancer cells induced by epidermal growth factor (EGF) in vitro. MTT assay was used to detect the inhibitory effect of luteolin on the proliferation of MCF-7 and MDA-MB-231 cells as well as the effect on the proliferation of MCF-7 cells induced by EGF. Western blotting was used to detect the effects of luteolin on the expression of epidermal growth factor receptor (EGFR), phosphatidylinositol 3-kinase (PI3K)/Akt, mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinases (Erk) 1/2 and signal transducers and activators of transcription-3 (STAT3) in MCF-7 cells induced by EGF. The results showed that luteolin could significantly inhibit the proliferation of MCF-7 and MDA-MB-231 cells, and the inhibitory effect on MCF-7 cells was more prominent. Moreover, luteolin could inhibit the proliferation of MCF-7 cells induced by EGF. Western blotting results showed that luteolin and AG1478 (an inhibitor of EGFR signaling) could inhibit the expression of p-EGFR and p-STAT3 in MCF-7 cells induced by EGF. Luteolin, LY294002 (an inhibitor of Akt signaling) and PD98059 (an inhibitor of Erk1/2 signaling) could inhibit the expression of p-Akt and p-Erk1/2 respectively in MCF-7 cells induced by EGF. Our data suggest that luteolin may inhibit EGF-induced activities of EGFR signaling pathway in human breast cancer cell lines, and PI3K/Akt, MAPK/Erk1/2, STAT3 signal pathways may be the major pathways that mediate the inhibitory effect of luteolin on EGFR signaling. Overall, our results may provide a theoretical foundation for the development of luteolin as anti-tumor drug.