title: Ribavirin uptake into human hepatocyte HHL5 cells is enhanced by interferon-α via up-regulation of the human concentrative nucleoside transporter (hCNT2).
abstract: Ribavirin is a broad spectrum antiviral that increases the response rate in chronic hepatitis C patients when administered in combination with IFNα. Ribavirin is a purine nucleoside derivative, transported into hepatocytes by nucleoside transporters. hCNT2 is the best candidate to mediate ribavirin uptake into hepatocytes due to its high-affinity for purines and its capacity to concentrate its substrates intracellularly. The aim of this study was to determine whether hCNT2 function is under IFNα modulation. IFNα treatment of the nontransformed human hepatocyte-derived cell line HHL5 induced a rapid and transient increase in hCNT2 activity after cytokine addition. hCNT2 activity up-regulation was associated with increased ribavirin accumulation into cells. This increase was consistent with the translocation of hCNT2-containing vesicles to the plasma membrane via a mechanism requiring ERK 1/2 and ROCK activation and cytoskeleton integrity. Longer treatments with IFNα induced transcriptional activation of the hCNT2-encoding gene (SLC28A2), resulting in a sustained increase in hCNT2-related activity. These observations are proof of concept for at least one of the putative mechanisms underlying the synergistic responses induced by combination therapy with IFNα and ribavirin.
authors: Department of Biochemistry and Molecular Biology, University of Barcelona, Institute of Biomedicine (IBUB) , 08028 Barcelona, Spain.
authors: Itziar
authors: I
authors: Pinilla-Macua
authors: Paula
authors: P
authors: Fernández-Calotti
authors: Sofía
authors: S
authors: Pérez-Del-Pulgar
authors: Marçal
authors: M
authors: Pastor-Anglada
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology; D002460:Cell Line; D022781:Hepatocytes / Q000187:drug effects*; D006801:Humans; D016898:Interferon-alpha / Q000235:genetics*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000235:genetics; D026901:Membrane Transport Proteins / Q000235:genetics; D033703:Nucleoside Transport Proteins / Q000235:genetics*; D012254:Ribavirin / Q000494:pharmacology*; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects* / Q000235:genetics*; D054460:rho-Associated Kinases / Q000235:genetics
chemical_list: D000998:Antiviral Agents; D016898:Interferon-alpha; D026901:Membrane Transport Proteins; D033703:Nucleoside Transport Proteins; C065171:cif nucleoside transporter; D012254:Ribavirin; D054460:rho-Associated Kinases