Immortalization of human dental papilla, dental pulp, periodontal ligament cells and gingival fibroblasts by telomerase reverse transcriptase.

Background: Human telomerase reverse transcriptase (hTERT) is catalytic subunit of human telomerase.
Methods: We studied the immortalization of a series of human dental and periodontal cells by ectopic expression of hTERT and co-expression of hTERT with human papilloma virus 16 (HPV16) or simian virus 40 (SV40). Differentiation abilities of the established cell lines were studied in terms of the mineralized matrix formation and gene expression.
Results: We established immortalized gingival fibroblasts by hTERT, dental papilla and periodontal ligament cells by hTERT and HPV16, and pulp cells by hTERT and SV40. The papilla and pulp cells showed mineralization and dentin sialophosphoprotein (DSPP) expression when cultured in the presence of beta-glycerophosphate. The immortalized periodontal ligament cells did not show mineralization or DSPP expression, although expressions of alkaline phosphatase, osteopontin and osteocalcin were detected.
Conclusions: These cell lines will be useful tools for studying the repair and regeneration of dental and periodontal tissues and various diseases including odontogenic tumors.