title: Telomerase activity in esophageal squamous cell carcinoma: down-regulation by chemotherapeutic agent.
abstract: OBJECTIVE
  Telomerase has been suggested as being necessary for continued cell growth and progression of cancer. Esophageal cancer and matched normal esophageal tissue from 54 patients were analyzed for telomerase activity, human telomerase reverse transcriptase (hTERT) mRNA expression, and their correlation with clinicopathological factors.
  
  
  METHODS
  Telomeric repeat amplification protocol was used for detection of telomerase activity and real time quantitative RT-PCR was used for hTERT mRNA. An esophageal carcinoma cell line was used to study the effect of chemotherapeutic agent on telomerase.
  
  
  RESULTS
  Telomerase activity was detectable in 79.6% of the tumor and 59.3% of the normal esophageal tissue. The level of telomerase activity in the tumor was significantly higher than that in the normal tissue. A significantly higher telomerase activity was observed in tumors with extensive blood vessel invasion. A significantly lower telomerase activity was observed in tumors that showed good response to preoperative chemotherapy than those with poor response. TE-9 cells exposed to 5-FU showed a diminished telomerase activity preceded by a time-dependent decrease in the mRNA expression of hTERT.
  
  
  CONCLUSIONS
  Telomerase activity was high in esophageal cancer tissue and showed positive correlation with blood vessel invasion. Chemotherapeutic agents may down-regulate telomerase activity.
authors.affiliation: Department of Surgery II, Nagoya City University Medical School, Nagoya, Japan. a.mitsui@med.nagoya-cu.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Mitsui
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kuwabara
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Iwase
authors.forename: Masami
authors.initials: M
authors.lastname: Mitani
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Shinoda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sato
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Toyama
authors.forename: Masahiko
authors.initials: M
authors.lastname: Sugiura
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Suzuki
authors.forename: Joji
authors.initials: J
authors.lastname: Kato
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Fujii
mesh_terms: D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology* / Q000627:therapeutic use; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000378:metabolism*; D016022:Case-Control Studies; D004268:DNA-Binding Proteins; D015536:Down-Regulation; D004938:Esophageal Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019098:Telomerase / Q000187:drug effects / Q000378:metabolism*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
chemical_list: D000964:Antimetabolites, Antineoplastic; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D019098:Telomerase; D005472:Fluorouracil