Gene molecular and ultrastructural study on the transforming activity of human papillomavirus genes by engineered recombinant retrovirus infection

Human papillomavirus(HPV) type 16 is the most prevalent viral type and its E6 and E7 early genes might play a key role in the carcinogenesis of cervical cancer in Chinese women. In order to elucidate the role of HPV-16 in the development of genital cancer, the present study was designed to transfect NIH3T3 cells with HPV-16 whole early genes and its E6, E7 genes separately. Besides the ordinary calcium phosphate/DNA coprecipitation technique, a newly designed recombinant retrovirus containing HPV-16 genes were used to infect cells for transfer the aim genes as shown in Fig.1.1). The cells transformed by recombinant retrovirus containing whole early gene and its E6-E7 respectively appeared more refractive, round shaped with rapid growth and loss of contact inhibition. Hundreds of cell colonies presented in cells transformed by the recombinant retrovirus after selected culture for one week, compared with the routine method, only a few colonies till 3 weeks. By using such a genomic engineering technique,the transforming activities have been shown to be most efficient. 2). The tumorigenicity of transformed cells: Transformed cells HZIP16-3T3 and HZIP16K-3T3, as well as negative controlled cells, NIH3T3 and pZIP-3T3 which was infected by recombinant retrovirus containing no HPV-16 gene, were transplanted into nude mice respectively. Tumours were formed in all mice within 15 days after inoculation of transformed cells (Fig.2). Whereas, no tumour was found in all controlled animals as long as 50 days. 3).