Transforming activity of cells transfected with hepatitis C virus nonstructural protein NS3

肝细胞癌与丙型肝炎病毒感染之间的关系已被提出。然而，其机制尚不清楚。由于丙型肝炎病毒的组织结构类似于黄病毒科成员，丙型肝炎病毒非结构蛋白NS3的生物学功能可能起到一定作用。为了测试这一点，将含有编码NS3的丙型肝炎病毒基因组片段5‘或3’半序列的表达载体(分别为pRcHCNS3-5‘和pRcHCNS3-3’)导入人或小鼠相关细胞。Hep G2细胞和IMR32细胞仅在pRcHCNS3-5‘2细胞中检测到丙型肝炎病毒特异性DNA。转染NIH3T3细胞，检测细胞生长情况。只有转染pRcHCNS3-5‘的细胞才能快速增殖并出现集落形成。将转染pRcHCNS3-5‘的NIH3T3细胞接种于裸鼠皮下。接种2周后，10只接种小鼠中有2只发现皮下肿瘤。特别是，所有小鼠都患上了肿瘤，显微镜下将其定义为纤维肉瘤。丙型肝炎病毒NS3的5‘端片段参与了细胞转化过程。这种与丙型肝炎病毒NS35‘端区域相关的致癌能力是否在丙型肝炎病毒感染的肝脏的癌变过程中起着重要作用，还需要进一步的研究。

The association of hepatocellular carcinoma (HCC) with hepatitis C virus (HCV) infection has been suggested. However, its mechanism is unknown. Because the organization of HCV resembles that of members of the family Flaviviridae, a biological function of the HCV nonstructural protein NS3 may play a role. To test this, either human- or mouse-associated cells were transfected with an expression vector containing cDNA for the 5'-or 3'-half sequence of the HCV genome segment encoding NS3 (pRcHCNS3-5' and pRcHCNS3-3', respectively).1. When Hep G2 cells or IMR32 cells were transfected with the vectors, HCV-specific DNA was detected only in the cells transfected with pRcHCNS3-5'.2. NIH 3T3 cells were transfected and cell growth were determined. Only cells transfected with pRcHCNS3-5' rapidly proliferated and indeed, showed the colony formations.3. NIH 3T3 cells transfected with pRcHCNS3-5' were inoculated subcutaneously in the flank of nude mice. After 2 weeks of the inoculation, subcutaneous tumors were found 2 of 10 inoculated mice. In particular, all mice developed the tumor, which was defined microscopically as fibrosarcoma.4. The HCV-specific DNA fragment was able to be amplified in cells isolated from the tumors.These results suggest that 5' region of HCV-NS3 is involved in cell transformation. Further studies are needed to see whether this tumorigenic capability associated with the 5' region of HCV-NS3 plays a significant role for the carcinogenesis of the HCV-infected liver.