RESUMO
OBJECTIVE: To investigate expression difference of several drug resistance related genes between sensitive and resistant ovarian carcinoma cells. METHODS: Cell lines resistant to cisplatin, carboplatin and taxol were established from ovarian carcinoma cell lines of SKOV3 and A2780, and their biological features were detected. The expressions of several genes related to drug resistance were measured by RT-PCR method. RESULTS: (1) The values of resistance index (RI) of resistant cells to relevant drugs were elevated 3 times or more, with different degrees of cross-resistance to several other drugs (RI 2 approximately 20). They grew more slowly than primary cells (Td elongated 1.4 approximately 2.4 times, P < 0.01) without obvious changes in G(1), G(2), and S ratios (P > 0.05). Intracellular concentrations of relevant drugs were reduced 2.0 approximately 8.5 times in resistant cells (P < 0.05). (2) p53, lung resistance protein-1 (LRP-1), multiple drug resistance related protein-1 (MRP-1) genes were expressed at lower levels in resistant cells than in sensitive cells; while protein kinase C (PKC), topoisomerase (topo) I, and topo II beta were expressed higher, no obvious alterations were found concerning glutathione S transferase-pi (GST-pi), and topo II alpha. Expression of multiple drug resistance-1 (MDR-1) gene was either elevated or reduced in different cells. CONCLUSIONS: The expressions of resistance related genes were widely different in different kinds of resistant cells, suggesting more than one pathway leading to resistance transformation. This adds more difficulties for clinical management.
