Oncogenic activity of insulin in the development of non-small cell lung carcinoma

Insulin is associated with the progression of numerous different types of cancer. However, the association between insulin and non-small cell lung carcinoma (NSCLC) remains unknown. The aim of the present study was to evaluate the role of insulin in the proliferation, migration and drug resistance of NSCLC cells, and to determine whether the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) pathway was involved. NSCLC cells were treated with insulin in the absence or presence of LY294002, an inhibitor of the PI3K/Akt pathway. Following co-incubation with insulin, cell proliferation and drug resistance were measured by MTT; cell migration was examined by wound healing and Transwell assays; and the expression of cyclin A, proliferating cell nuclear antigen (PCNA), p27, matrix metalloproteinase 3 (MMP3), P-gp and proteins involved in the PI3K/Akt pathway were assessed via western blotting. The results of the current study demonstrated that insulin enhanced the proliferation, migration and drug resistance of NSCLC cells. Correspondingly, insulin upregulated the expression of cyclin A, PCNA, MMP3, P-gp and downregulated p27 expression in NSCLC cells. Following treatment with insulin, it was demonstrated that phospho-Akt expression increased in a dose-dependent manner. However, the effects of insulin on NSCLC cells was inhibited by the PI3K/Akt pathway inhibitor LY294002. Therefore, the results of the current study indicate that insulin is associated with the development of NSCLC by activating the PI3K/Akt pathway. This may improve understanding of the mechanism of action of insulin in NSCLC in the future.