Establishment Of A Gefitinib-resistant Human Colon Carcinoma Cell Line HT-29/Gefitinib And Study Of The Preliminary Resistant Mechanisms

Objective:Gefitinib is small molecule inhibitor of tyrosine kinase,which competitively inhibits binding of adenosine triphosphate(ATP) to the receptor kinase domain of the epidermal growth factor receptor. The inhibitor prevents EGFR signaling pathway and plays the role of antitumor. In preclinical studies and clinical trials, gefitinib have demonstrated growth inhibition in a variety of solid tumor types including no small cell lung cancers, breast, colon, prostate, ovarian, et al. In clinical, the inhibitor has provided anti-tumor activity in patients with locial advanced and metastatic non-small cell lung carcinoma. However, the clinical date demonstrated that only a small part of patients responded to the inhibitor: the Easters are about 25-35%, the Westers are only 8-15%; furthermore, even with responders to gefitinib, it was observed that disease progression could occur within a few months of the therapy, which is acquired resistance to the TKI. The experiment is to establish a human colon carcinoma HT-29/Gefitinib cell line resistant to gefitinb, and preliminarily study its resistance mechanisms.Methods:The gefitinib-resistant human colon cell line HT-29/gefitinib was induced by stepwise selection on exposuring to increasing doses of gefitinib. The IC50 and resistance index were tested by MTT assay. The growth curve was painted and the double time was accounted by cell counting assay. The distributions of cell cycles were detected by flow...