title: The effects of telomerase inhibitors on lymphocyte function.
abstract: BACKGROUND
  Telomerase is an enzyme that is present in both cancerous cells and lymphocytes. Telomerase inhibitors block tumor cell growth and are being considered for chemotherapy. This study tested whether telomerase inhibitors suppress growth of leukemic cell lines and blood lymphocytes (PBMC).
  
  
  RESULTS
  Reverse transcriptase inhibitors azidothymidine (AZT) and 3'-deoxy-2:3'-didehydrothymidine (d4T) decreased growth of all cells while dideoxyinosine (ddI) had no effect on Jurkat cells but increased growth of PBMC. The oligonucleotide (TTAGGG)3, which mimics the telomeric sequence, decreased growth of all cells. Inhibition by AZT, d4T and (TTAGGG)3 was manifested at 48-96 hours after addition to the cultures but not at 24 hours. The inhibition was partially to totally reversible upon inhibitor removal, indicating that the compounds were not cytotoxic but only suppressed cell growth temporarily.
  
  
  CONCLUSIONS
  Immunosuppression may result from the use of telomerase inhibitors during chemotherapy but should only be temporary.
authors.affiliation: Department of Biology, University of Northern Iowa, Cedar Falls 50614, USA.
authors.forename: L
authors.initials: L
authors.lastname: Beltz
authors.forename: R
authors.initials: R
authors.lastname: Moran
authors.forename: O
authors.initials: O
authors.lastname: Elsawy
authors.forename: J
authors.initials: J
authors.lastname: Sadler
authors.forename: J
authors.initials: J
authors.lastname: Jurgenson
mesh_terms: D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects*; D019098:Telomerase / Q000037:antagonists & inhibitors*; D014407:Tumor Cells, Cultured
chemical_list: D004791:Enzyme Inhibitors; D019098:Telomerase