Abstract
Several studies have demonstrated that growth arrest-specific protein 6 (Gas6) and Axl are highly expressed in various tumor tissues, such as renal cell and esophageal carcinoma. However, the effect of the Gas6/Axl signaling pathway on lung adenocarcinoma is still unclear. The aim of the present study was to investigate the effect of the Gas6/Axl signaling pathway on lung adenocarcinoma cells and its mechanism of action, which may provide a novel target for the clinical treatment of lung adenocarcinoma. Human lung adenocarcinoma tissues were used to examine the activation of the Gas6/Axl signaling pathway. In addition, the human lung adenocarcinoma cell line A549 was employed to study the effects of the Gas6/Axl signaling pathway on the proliferation, migration, invasion and apoptosis of lung adenocarcinoma cells. Recombinant human Gas6 protein and inhibitor TP-0903 were used to activate and inhibit the Gas6/Axl signaling pathway, respectively. The results revealed that Gas6 and Axl expression level was increased in human lung adenocarcinoma tissues compared with adjacent healthy tissues. After inhibition of the Gas6/Axl signaling pathway with TP-0903, p21, p53, caspase 3, caspase 8 and caspase 9 exhibited higher expression level in A549 cells. The opposite effect was observed when the Gas6/Axl signaling pathway was activated. In addition, the migratory and invasive ability of A549 cells was determined via wound-healing and Transwell invasion assays. The results indicated that the migratory and invasive ability of A549 cells was significantly increased when the Gas6/Axl signaling pathway was activated and inhibition of Gas6/Axl signaling pathway caused the opposite results. Activity of Gas6/Axl signaling pathway was shown to be positively associated with cell proliferation by Cell Counting Kit 8 and clone formation assays. In conclusion, the Gas6/Axl signaling pathway was revealed to promote the proliferation, migration and invasion and inhibit the apoptosis of lung adenocarcinoma cells, which serve important roles in the progression of lung adenocarcinoma.