Comparison of telomerase levels before and after differentiation of two cell lines of human neuroblastoma

Background. Telomerase is the enzyme that is responsible for maintaining te lomere length in human germ cells, tumor cells, and immortalized cells. Its specific role in the immortilization process is unknown. This study was pe rformed to determined whether the level of telomerase activity in human neu roblastoma cell lines correlated with their level of differentiation. We pr oposed that as neuroblastoma cells differentiated into more mature or benig n cells, the levels of telomerase expression would decrease, Material and Methods, Two human neuroblastoma cells lines, SK-N-AS and SK-N -DZ, were differentiated using retinoic acid. These cells were assayed for telomerase activity by the telomere repeat amplication protocol (TRAP) befo re, during, and after treatment with retinoic acid for 8 days, Untreated ce lls were used for control and were compared to the retinoic acid-treated ce lls. Differentiation of the cell lines was confirmed by assaying expression of ret mRNA using the reverse-transcriptase polymerase chain reaction (RT- PCR) and gel electrophoresis of the radiolabeled products. Results. No statistical difference in telomerase activity was noted between control and treated groups. Conclusions. While telomerase activity has been shown by others to correlat e with tumor aggressiveness in human neuroblastoma cells, the mechanism tha t is involved appears to be separate from cellular differentiation.