[Biological characterization of immortalized porcine chondrocytes by introduction of telomerase].

The aim of this project was to acquire a clonal immortalized porcine chondrocyte cell line and to determine its biological characterization. Porcine auricle chondrocytes were infected with a retroviral vector pBABE-hTERT followed by selection with 2 micrograms/ml puromycin. RT-PCR and PCR-ELISA performed on separated colonies showed a cell line (TL1) with high and stable ectopic expression of hTERT. The growth curve, HE staining, flow cytometry, and tumorigenicity were analyzed to define the biological characterization of the immortalized chondrocytes. TL1 cells showed an increase in cellular viability and the reduction in apoptosis. But there was no malignant transformation and tumor development in nude mice. The changes of chondrocyte marker expression in this cell line revealed that it remained unstable phenotype. So high ectopic expression of hTERT is able to extend the life span of chondrocytes, but it unable to keep their differentiated phenotype during serial monolayer culture in vitro.