Abstract
Telomeres are the distal ends of human chromosomes composed of tandem repeats of sequence TTAGGG. Human telomeres undergo progressive shortening with cell division. Telomerase is an enzyme that directs the synthesis of telomeric repeats at the chromosome ends, and it is implicated in cellular immortalization and senescence. Among three major components of human telomerase that have been cloned, human telomerase reverse transcriptase (hTERT) is reported to be the most important for the enzyme activity. In this study, we tried to immortalize human oral keratinocytes by gene transfer of hTERT with or without HPV16 E6 or E7 gene. As a result, we established immortalized oral keratinocytes by gene transfer of hTERT and HPV16 E7. The immortalized cells, when cultured in increased calcium concentration media, showed stratification and up-regulation of involucrin and transglutaminase I genes, which are differentiation markers of epithelial cells. These results indicated that this cell line had a normal differentiation capacity and was useful for study of the biological characterization and molecular mechanisms of carcinogenesis of normal oral keratinocytes.
