NORMAL HUMAN FIBROBLASTS IMMORTALIZED BY INTRODUCTION OF HUMAN PAPILLOMAVIRUS TYPE-16 (HPV-16) E6-E7 GENES

This report demonstrates that normal human fibroblasts can be immortal ized by the introduction of HPV-M E6-E7 genes. We designed zinc-induci ble expression plasmids with HPV-16 E6, E7 or both. Each plasmid was i ntroduced into normal human fibroblasts (TIG-3 cells) using lipofectio n methods. Only transfectants with the HPV-16 E6-E7 zinc-inducible exp ression plasmid, which were cultured in medium supplemented with 100 m u M ZnSO4, overcame crisis and could be cultured over 200 population d oubling levels (PDLs), These cell lines showed the reactivation of tel omerase after crisis, and morphological alterations were also observed .