Establishment of novel human esophageal cancer cell line in relation to telomere dynamics and telomerase activity

The telomere and the telomerase in human esophageal cancer are not yet comp letely understood. The regulatory mechanism of telomerase activity and telo mere dynamics has drawn considerable attention. It is generally assumed tha t when telomerase has been activated, no further telomere shortening should ensue; however, a much more complex pattern of telomere dynamics may exist in telomerase-positive cancer cells. A novel human esophageal cancer tell line (KAN-ES) was established and characterized. Using KAN-ES and its seria lly passaged subclones up to the 55th generation, we determined the alterat ion of telomere length (TRF), telomerase activity (TA), telomerase RNA expr ession (hTR), population doubling time, karyotype, and cytokeratin 14 expre ssion during the process of establishing a cancer cell line. We found that the TRF was maintained between 4.0 and 5.0 kh during the serial passages, d espite sustained high TA (assessed by an in vitro TRAP assay). No close rel ationships were found among TRF, TA, and hTR expression. TA and telomere dy namics were not associated with cellular growth ability and differentiation . However, the number of population doublings showed significant correlatio ns with both the TA and doubling times. In conclusion, these dissociations between telomere dynamics and TA support the existence of additional contro ls on TRF in cancer cells. KAN-ES and its restored subclones should prove a valuable resourse for esophageal cancer research.