Background and objective: Chemotherapy is the main treatment for colon cancer, while multidrug-resistance is the main reason for chemotherapy failure and tumor relapse. This study was to establish two oxaliplatin-resistant colon cancer cell lines and evaluate their biological characteristics.
Methods: Oxaliplatin-resistant colon cancer cell lines SW620/L-OHP and lovo/L-OHP were established in vitro by continuous exposure to oxaliplatin (L-OHP) of low and gradually increased concentration. Growth curve, cross-resistance and resistance index of the oxaliplatin-resistant cell lines to various anti-cancer agents were determined by CCK8 assay. The expressions of P-glycoprotein (P-gp), multidrug-resistance protein 1 (MRP1) and MRP2 were detected by Western blot. Cell cycle distribution as well as the expression of CD133 and CD44 were measured by flow cytometry.
Results: It took 10 months to establish the SW620/L-OHP and LoVo/L-OHP cell lines with stable resistance to oxaliplatin. Cross-resistance to 5-fluorouracil, etoposide, cisplatin, vincristine and epirubicin but not to paclitaxel was observed. Longer doubling time, higher proportion of cells in G(0)/G(1) phase and lower proportion in G(2)/M phase were observed in the two oxaliplatin-resistant cell lines compared with their parental cell lines. The expression of MRP2 in the oxaliplatin-resistant cells was up-regulated, while those of P-gp and MRP1 had no significant change. CD133 was overexpressed while CD44 level remained unchanged in SW620/L-OHP and LoVo/L-OHP cells.
Conclusions: SW620/L-OHP and LoVo/L-OHP cell lines show a typical and stably resistant phenotype and may be used as research models.