Integration of HPV-16 DNA in cervical carcinoma cell line CC3/CUHK3 and its xenografts

A recently established cell line, designated CC3/CUHK3, derived from a squamous cell carcinoma of the uterine cervix of a Hong Kong Chinese patient was investigated for its association with human papillomavirus (HPV) by Southern blot hybridization studies. A "grafted tumour" or xenograft of CC3/CUHK3 has also been successfully established in athymic mice, which showed similar histology to that of the original biopsy. The epithelial nature of the xenografts, like the original biopsy. The epithelial nature of the xenografts, like the original tumour specimen, was also confirmed by transmission electron microscopy which demonstrated the presence of desmosomes and tonofilaments. Moreover transmission electron microscopic examination revealed no HPV particle in either the tumour biopsy or the xenograft tissues. Analysis of the DNA samples extracted from the cervical cancer cell line and the xenograft tissues derived from it showed the presence of HPV type 16 DNA. No DNA sequence related to HPV type 6, 11, or 18 was demonstrated. The viral DNA was found to be integrated into the cellular genome at multiple sites as single copy or head-to-tail tandem repeats. Deletion or rearrangement of the HPV DNA had probably occurred on or subsequent to integration. Viral sequence deletion has also been observed in the grafted tumours derived from CC3/CUHK3.