AG1478 inhibits the migration and invasion of cisplatin-resistant human lung adenocarcinoma cells via the cell cycle regulation by matrix metalloproteinase-9

AG1478 is a specific epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor. The effect of AG1478 on the A549/DDP (cisplatin-resistant human lung adenocarcinoma) cell line is unknown. The aim of the present study was to investigate the effects of AG1478 on the A549/DDP cell line and its sensitive parental A549 cell line. The two cell lines were treated with AG1478 and the growth, proliferation, migration and invasion of the tumor cell lines were measured using flow cytometry, as well as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing and Transwell system assays. The expression of metastasis-associated genes and proteins was evaluated by quantitative-polymerase chain reaction and western blot analysis. The molecular mechanisms were investigated using short-interfering RNAs (siRNAs). The phosphorylation status of the key cell cycle protein, retinoblastoma (Rb), was also investigated. The results revealed that AG1478 inhibited the growth of the two cell lines with varying potency, and that the A549/DDP cell line was more sensitive to AG1478 than the A549 cell line. Cell migration and invasion, as well as matrix metalloproteinase (MMP)-9 and E2F1 expression were significantly inhibited. However, MMP-9 expression was also significantly suppressed in the two cell lines following transfection with E2F1-targeting siRNA. In addition, AG1478 significantly arrested A549/DDP and A549 cells in G(1) phase, with a corresponding reduction in the S phase. The phosphorylation of Rb protein at various sites was selectively inhibited by AG1478 at various time points. The results indicate that AG1478 may provide a clinical therapeutic approach for certain types of cisplatin-resistant lung cancer.