Establishment of a drug resistant human hepatoma cell line (QGY/DDP) induced by cisplatin in vitro / 解放军医学杂志

ABSTRACT

Objective To establish a drug resistant human hepatoma cell line (QGY/DDP) induced by cisplatin (DDP) in vitro, and to investigate its biological features and mechanisms of resistance. Methods The drug resistant cell line (QGY/DDP) of hepatoma was established by intermittent administration of stepwise increas of the dosage of DDP. Drug sensitivity was evaluated by MTT assay. Cell counting was employed to graph the growth curve and to calculate the doubling time. Flow cytometry (FCM) was used to study the cell cycle distribution. In addition, the intracellular platinum accumulation was detected by atomic absorption spectrometry, and the expressions of P-glycoprotein (P-gp) and glutathione S-transferase-? (GST-?) were analyzed by FCM. Results QGY/DDP cell line was established successfully after 3 months with stable resistance to DDP, and the resistance index (RI) was 10.81. The established cell line exhibited obvious cross-resistance to 5-FU, VCR, MMC, EPI and HCPT. Compared with parental cell line, the QGY/DDP cell line grew slower and its doubling time became longer. The proportion of G0/G1 phase cells of the resistant cells was significantly higher than that of their parental cells, whereas the proportion of S and G2/M phase cells was decreased. The cellular platinum accumulation was obviously decreased in the QGY/DDP cell line, and the expression of GST-? in QGY/DDP cells was higher than that of their parental cells, but no over expression of P-gp was found in the resistant cell line. Conclusions QGY/DDP cell line shows the typical and stable resistant phenotype and possesses the basic biological features of resistant cells. The resistance of the cell line to DDP may be due to the reduction of intracellular platinum accumulation and the over expression of GST-?, but may not be related to the expression of P-gp.