Spontaneous mutation of p53 gene in human papillomavirus type 16 E7-immortalized human laryngeal epithelial cells

The E7 gene is one of the principle transforming genes of human papillomavirus type 16 (HPV 16). In this study, we show that HPV 16 E7 gene could immortalize in vitro primary human laryngeal epithelial cells (HLEC cells) without cooperation of the viral E6 gene. The HPV 16 E7-immortalized HLEC cell line had acquired a mutation of a tumor suppressor gene, p53, during the immortalization process. Using immunofluorescence assay, nuclear accumulation of p53 protein was found in the cell line. These results suggest that HLEC cells can be immortalized in vitro by the cooperative activities of HPV 16 E7 gene and a spontaneous mutation of the endogeneous p53 gene.