Involvement of PI3K in HCV-related lymphoproliferative disorders

Hepatitis C virus (HCV) core protein has been shown to deregulate cell growth and programmed cell death in hepatoma cells, but only minimal informations are available about its possible role on B-lymphoproliferative disorders (LPDs). The aim of our work was to analyze the biological activity of HCV core protein on B-cell proliferation. We established Wil2-ns and Ramos B-cell lines that stably expressed the HCV core protein. Growth curve, thymidine incorporation analysis, as well as the expression of PCNA and activated-ERKs demonstrated that HCV core protein induced an increased growth in both cell lines. Interestingly, the HCV core protein expression determined, in our model, a downregulation of DNp73 and an upregulation of DNp63, which was essential for the maintenance of viral-dependent effects on cell growth. Finally, we have identified phosphoinositide 3-kinase (PI3K) as mediator of HCV core-dependent transcriptional increase of DNp63, which in turn correlated with the increasing of lymphocyte proliferation. In primary B-lymphocytes, derived from HCV-related low-grade non-Hodgkin's lymphoma patients, consistent results were obtained. These findings provide evidence for a possible pathogenetic role played by HCV core protein in HCV-related lymphomagenesis; it could occur through the deregulation of PI3K activity, consequent activation of Akt and overexpression of DNp63.