Abstract
BACKGROUND AND OBJECTIVE: It has been proven that Src played pivotal roles in carcinogenesis, cancer progression and metastasis. The aim of this study is to explore the roles of Src phosphorylation on lung cancer cells. METHODS: Western blot and immunoprecipitation was used to detect the expression and phosphorylation of Src in lung cancer cells. MTT and Boyden chamber assay was used to examine the effects of inhibition of Src phosphorylation on proliferation and invasion of lung cancer cells in vitro, respectively. RESULTS: pp60src was expressed in all lung cancer cell lines in this study. All 5 non-small cell lung cancer (NSCLC) cell lines had increased autophosphorylated tyrosine-418, while nearly no phosphorylated Src in small cell lung cancer SBC5 cell line was detected. The effect of inhibition of Src tyrosine kinase on cell proliferation varied among the lung cancer cell lines. Submicromolar Src tyrosine kinase inhibitor (≤1 μM) remarkably suppressed the proliferation of PC-9 and A549 cells in a dose dependent manner (P < 0.05), while the same concentration of Src tyrosine kinase inhibitor had no significant effect on proliferation of H226, PC14PE6 and RERFLCOK cells. Invasiveness of lung cancer cells was significantly suppressed by Src tyrosine kinase in a dose-dependent manner (P < 0.05). CONCLUSIONS: Phosphorylation of Src, but not over-expression, plays a pivotal role in proliferation and invasion of NSCLC cell lines in vitro.