Study On The Role Of IGF1R Signal Pathway In Non-small Cell Lung Cancer With Drug Resistance To Gefitinib

Objective1.To establish a gefitinib-resistant human lung adenocarcinoma A549/GR cell line, and to provide a cell model for studying the molecular drug resistance mechanisms and screening the molecular markers for targeted treatment;2.To further decipher the Role of Insulin-Like Growth Factor-I Receptor and its downstream signaling pathway in EGFR-TKIs Resistance.Methods Gefitinib-resistant A549/GR cell line was induced by stepwise selection after exposure to increasing doses of gefitinib. Morphological changes was observed under inverted microscope in natural growth condition or after HE staining. CCK8method was used to detect the sensitivities of A549and A549/GR cells to Gefitinib. Population doubling time and Cell growth curves were plotted by CCK-8 assay. EGFR,IFG1R,AKT1,ERK1mRNA expression analysis of A549/GR wasimplemented by quantitative real-time PCR (q-RT-PCR) and A549cell line were used asa contrast.Results A gefitinib-resistant lung adenocarcinoma cell line A549/GR has beenestablished successfully with the RI being6.00detected by CCK-8assay, andshowed a markedly increased proliferation rate than Parental cells. Morphologicalchanges in gefitinib-resistant cells included loss of polarity and being spindle-shaped.and Q-RT-PCR method indicated that, compared with parental cells, A549/GR cells hadmildly elevated levels of mRNA in EGFR,IGF1R,AKT1，ERK1(p<0.05).Conclusion Together with the IGF1R, the activation of MAPK/ERK pathwaypartially causes acquired resistance to gefitinib in non-small cell lung cancer cells withthe wild-type epidermal growth factor receptor.