Cell specific down-regulation of multidrug resistance MRP1, MRP2, MDR1 and BCRP expression by the non-structural 5A protein of hepatitis C virus

ROSSO, N; RIVERO, CW; CUESTAS, ML; MINASSIAN, ML; GENTILE, EA; CASTILLO, AI; ANDREETTA. AM; TRINKS, J; TIRIBELLI, C; OUBIÑA, JR; MATHET, VL

Congreso; ATP-Binding Cassette (ABC) Proteins: From Multidrug Resistance to Genetic Diseases.; 2010

Background/Aims: The hepatitis C virus (HCV) is a major cause of chronic liver disease. The non-structural 5A (NS5A) protein interferes with the response to interferon and appears to perform a crucial role in viral replication. Multidrug resistance is generally accepted as an important cause of treatment failure in patients with neoplastic or infectious diseases, playing a critical role in detoxification processes. In the present study, we investigated the effect of the NS5A protein on the expression and functional activity of several ATP-dependent transport proteins, all members of the ABC super family. Methods: Comparative quantitative real time polymerase chain reaction (qPCR) was carried out for mrp1, mrp2, mdr1, and bcrp mRNAs in both HeLa and Huh7cells expressing NS5A at different times post-transfection (18, 30 and 42h). MDR1, MRP1 and BCRP proteins levels were studied by western blot with monoclonal antibodies. The functional activity of these pumps was also analyzed. Results: A dose-dependent down-regulation of mrp1, mrp2, mdr1 and bcrp expression was documented in Huh7 cells when the NS5A protein was expressed. In contrast, no differences were observed in the expression of mrp1, mrp2 and bcrp in NS5A-transfected HeLa cells. In spite of such opposite results, no significant differences were detected in Rhodamine 123 (Rho123) and 3, 3’-diethyloxacarbocyanine iodide (DiOC2) elimination. Conclusions: A decrease in mrp1, mrp2, mdr1 and bcrp expression was dependent on the NS5A level expression in Huh7 cells. These results warrant further in vivo studies in HCV patients with cholestasis. It is worth pointing out that multidrug resistance proteins studied in this work are implicated in both antitumoral and antiviral drug transport.