OBJECTIVETo study the effect of hepatitis C virus nonstructural protein NS(3) (HCV NS3) on telomerase activity and carcinogenesis.

METHODSStreptavidin-peroxidase (SP) conjugated method was used to detect the expression of HCV NS(3) protein in NIH3T3 cells transfected with plasmid pRcHCNS(3)-5' and pRcHCNS(3)-3'. Telomerase activity was detected by an in situ telomerase activity labeling method, telomeric repeat amplification protocol polymerase chain reaction (TRAP-PCR) and telomerase PCR enzyme linked immunosorbent assay (ELISA) technology in the transfected and non-transfected NIH3T3 cells.

RESULTSHCV NS(3) protein was expressed in the NIH3T3 cells transfected with plasmid pRcHCNS(3)-5' expressing HCV NS(3) C-terminal deleted protein or with plasmid pRcHCNS(3)-3' expressing HCV NS(3) N-terminal deleted protein. The positive signal of HCV NS(3) protein was localized in the cytoplasm of NIH3T3 cells, and the signal intensity of the former was stronger. Telomerase activity in NIH3T3 cells transfected with plasmid pRcHCNS(3)-5' was stronger than that in NIH3T3 cells transfected with plasmid pRcHCNS(3)-3' (P < 0.01), whereas telomerase activity in NIH3T3 cells transfected with plasmid pRcCMV or untreated NIH3T3 cells was weaker than that in NIH3T3 cells transfected with plasmid pRcHCNS(3)-3' (P < 0.05). The expression level of HCV NS(3) protein was significantly correlated with the strength of telomerase activity (P < 0.05). The results obtained by in situ telomerase activity labeling corresponded to the results by telomerase PCR ELISA technology.

CONCLUSIONSHCV NS(3) protein may activate telomerase through endogenous mechanism to induce host cell transformation. The effect of HCV NS(3) C-terminal deleted protein on telomerase activity in the host cell may be stronger than that of HCV NS(3) N-terminal deleted protein. In situ telomerase activity labeling was a reliable technology for studying pathological morphology and telomerase activity in tissues and cells.