HEPATITIS-C VIRUS NONSTRUCTURAL PROTEIN NS3 TRANSFORMS NIH 3T3 CELLS

Clinical evidence suggests that hepatitis C virus (HCV) is etiological ly involved in hepatic cancer and liver cirrhosis. To investigate whet her the HCV nonstructural protein NS3 has oncogenic activity, NM 3T3 c ells were transfected with an expression vector containing cDNA for th e 5'- or 3'-half sequence of the HCV genome segment encoding NS3. Only cells transfected with the 5'-half cDNA rapidly proliferated, lost co ntact inhibition, grew anchorage independently in soft agar, and forme d tumors in nude mice. PCR analysis confirmed the presence of the 5'-h alf DNA in the transfectants These results suggest that the 5' region of the HCV genome segment encoding NS3 is involved in cell transformat ion.