RESUMO
Objective:To investigate the effect of afatinib, a tyrosine kinase inhibitor, on the proliferation, cell cycle, and apoptosis of human breast cell lines, and compare its effects with those of gefitinib. Methods:Three human breast cell lines, MCF-7, T47D, and MDA-MB-231, were cultured as cell models. A methyl thiazolyl tetrazolium assay was utilized to measure cell viability. Flow cytometer was used to analyze the cell cycle arrest (PI staining) and apoptosis rates (Annexin-V/PI staining). The protein expression was detected by Western blot analysis. Results:The proliferation of three human breast cell lines was significantly inhibited by afatinib, and the IC50 levels of MCF-7, T47D, and MDA-MB-231 were 0.101, 0.141, and 0.887μmol/L, respectively. The G0/G1 phase cell ratio increased con-siderably 24 h after afatinib was added to T47D or MDA-MB-231. The cell apoptosis rate also increased in the two cell lines (88.9%and 58.1%). The cleavage of apoptosis pathway proteins PARP and caspase-3 was also promoted by afatinib. Phosphorylation of EGFR was significantly inhibited by afatinib in the MDA-MB-231 cell line. Finally, the inhibition effect of afatinib was stronger than that of gefi-tinib. Conclusion: Afatinib could significantly inhibit the proliferation of breast cancer cells and promote apoptosis. The effect was dose-dependent. Afatinib was a more effective tyrosine kinase inhibitor as compared with gefitinib.
RESUMO
Objective To investigate the effects of a new c-Met inhibitor SU11274 on apoptosis and motility of c-Met-positive basal-like breast cancer cells MDA-MB-231. Methods The concentrations of SUl1274 were set to 0,0.1,1,10 and 20 μmol/L.Morphological change of apoptotic cells was analyzed by Hoechst33342,MitroTrackerRed and Yo-pro-1 staining.The apoptotic rate of MDA-MB-231 cells were determined by Annexin V/PI double-staining. The expression of apoptosis related proteins (Bcl-XL,Caspase-3 and PARP) and phosphorylation levels of c-Met and Akt were analyzed by Western blot.The capability of motility were measured by wound-healing assay and chemotaxis assay. Results After treatment by SU11274( 10 μmol/L) for 48 h,shrinking apoptotic cells of MDA-MB-231 was observed by flurescent microscope and nuclear fragmentation was seen.Annexin V/PI double-staining showed SU11274induced apoptosis of MDA-MB-231 cells (P ＜ 0.05 ),and the apoptotic rates were (7.3 ± 0.9) ％,( 14.1 ±0.6) ％,(35.5 ± 4.4) ％ and (48.2 ± 5.3 ) ％,respectively.SU11274 downregulated the expression of Bcl-XL and promoted the dissection of Caspase-3 and PARP in a dose dependent relationship.SU11274 prolongs the wound-healing time,decreases the migration cell count (P ＜ 0.05 ) and effectively inhibits the phosphorylation of c-Met and its downstream key proteins Akt in a dose-dependent manner.Conclusions C-Met inhibitor SU11274 induces apoptosis and inhibits the motility of c-Met-positive basallike breast cancer cell line MDA-MB-231,probably through inhibiting phosphorylation of c-Met/PI3K/Akt.