ABSTRACT
Aim To establish NCI-H446/EP for small cell lung cancer resistant cells resistant to cisplatin and etoposide, and to evaluate their biological characteristics and multidrug resistance. Methods Nude mice were subcutaneously inoculated with NCI-H446 cells of SCLC to construct an in vivo model of xenograft tumor, and were given first-line EP regimen treatment for SCLC, inducing drug resistance in vivo, and stripping tumor tissue in vitro culture to obtain drug-resistant cells. The resistance coefficient, cell doubling time, cell cycle distribution, expression of multidrug resistance gene (MDR1), and drug resistance-related protein were detected in vitro, and the drug resistance to cisplatin and etoposide in vivo were verified. Results Mice with NCI-H446 tumors acquired resistance after eight weeks' EP regimen treatment, and the drug-resistant cell line NCI-H446/EP was obtained by isolation and culture in vitro. The resistance factors of this cell line to cisplatin, etoposide, SN38 and doxorubicin were 12.01, 18.36, 65.4 and 10.12, respectively. Compared with parental cells, the proportion of NCIH446/EP cells in Q