Establishment And Characterization Of A Gefitinib Induced Resistant Human Colon Carcinoma Cell Subline

Purpose: Gefitinib (ZD1839, iressa), a selective epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is undergone preclinical and clinical evaluation in several solid tumors. However, almost all patients responded to Gefitinib were observed that disease progression within a few months of the therapy. We called it had acquired resistance to Gefitinib. To explore the mechanism of Gefitinib acquired resistance after treatment, established human colon carcinoma LOVO/Gefitinib cell line and studied its characteristics.Method: The Gefitinib-resistant human colon carcinoma cell line LOVO/Gefitinib was established by repeatedly exposing the cell line LOVO to gradually concentration of Gefitinib. Cell growth curve was painted and the doubling time was accounted by cell counting assay; Cell cycle distribution was measured by the flow cytometry (FCM); The resistant index (RI) to Gefitinib and the resistance of LOVO/Gefitinib to 5-Fu, DDP, L-OHP, CPT-11 was detected by the methylthiazolyl tetrazolium assay (MTT); The expression of P-gp of parental and resistant cells line were assessed with S-P immunocytochemical method; The level of vascular endothelial growth factor (VEGF) in the culture medium without serum by enzyme-labeled immunosorbent assay (ELISA).Result: The Gefitinib-resistant human colon carcinoma cell line LOVO/Gefitinib was established .The resistant index to Gefitinib was 14.13.Doubling time of LOVO and LOVO/Gefitinib were 37.7h and 31.3h,respectively, as evaluated by the growth curve. The rate of cell proliferation of LOVO/Gefitinib was shorter than that of LOVO. The number of LOVO exhibiting G0-GI, S, G2-M phase were 65.3%, 33.5%,...