sc-236 and Carcinoma--Hepatocellular

Doxorubicin is a chemotherapeutic drug widely used for the treatment of hepatocellular carcinoma but its efficacy is restricted by multidrug resistance. Non-steroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase (COX)-2-selective inhibitors exhibit anti-cancer properties as well as abilities to overcome drug resistance. In the present study, indomethacin (a NSAID) and SC236 (a COX-2-selective inhibitor) enhanced the cytotoxicity of doxorubicin in the hepatocellular carcinoma cell line HepG2 and its drug-resistant sub-line R-HepG2. Both drugs increased the intracellular accumulation and retention of doxorubicin in vitro. The effects were not reversed by prostaglandin E(2), implicating a COX-independent mechanism. Indomethacin and SC236 partially reversed the increase in expression of P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1) induced by doxorubicin in R-HepG2 cells. In conclusion, indomethacin and SC236 increased the intracellular accumulation and retention of doxorubicin and thus its cytotoxicity in HepG2 and drug-resistant HepG2 cells. These effects, mediated through decrease in P-gp and MRP1 expression and/or direct inhibition of P-gp activity, may improve multidrug resistant-cancer chemotherapy.

Topics: Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; ATP Binding Cassette Transporter, Subfamily B, Member 1; Blotting, Western; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Separation; Cyclooxygenase 2 Inhibitors; Doxorubicin; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Drug Synergism; Flow Cytometry; Humans; Indomethacin; Liver Neoplasms; Microscopy, Confocal; Multidrug Resistance-Associated Proteins; Pyrazoles; Sulfonamides