title: Acyclic retinoid induces partial differentiation, down-regulates telomerase reverse transcriptase mRNA expression and telomerase activity, and induces apoptosis in human hepatoma-derived cell lines.
abstract: OBJECTIVE
  Acyclic retinoid (AR; all trans-3,7,11,15-tetramethyl-2,4,6,10,14-hexadecapentaenoic acid) prevented hepatocarcinogenesis in animal models and in a randomized clinical trial by eradicating premalignant and latent malignant clones of transformed cells from the liver. We investigated the possible mechanism of this clonal deletion at the cellular level.
  
  
  METHODS
  Human hepatoma-derived cell lines, PLC/PRF/5, HuH-7, and JHH-7, were treated in vitro with AR. Secretion of albumin and that of lectin-reactive isoform of alpha-fetoprotein (AFP-L3) were measured as markers of differentiation and dedifferentiation of the cells, respectively. Telomerase reverse transcriptase (TERT) mRNA expression and telomerase activity were measured by reverse transcriptase polymerase chain reaction (RT-PCR) and stretch PCR assay, respectively. Caspase activities were measured by colorimetric protease assay. Mitochondrial membrane permeability transition was examined by Rhodamine staining.
  
  
  RESULTS
  Production of albumin was recovered while that of AFP-L3 was reduced after exposure of the cells to 10 microM AR for 2 days. This differentiation was maintained for another 2 days without retinoid. In parallel, both TERT mRNA expression and telomerase activity were down-regulated. The cells subsequently died due to apoptosis after 4-6 experimental days. Serial increases in mitochondrial membrane permeability and caspase-9 and -3 activities induced apoptosis.
  
  
  CONCLUSIONS
  AR first induces differentiation and reduces telomerase activity. Subsequent apoptosis may contribute to the eradication of the clone.
authors: First Department of Internal Medicine, Gifu University School of Medicine, 40 Tsukasa-machi, Gifu 500-8705, Japan.
authors: Ichiro
authors: I
authors: Yasuda
authors: Yoshimune
authors: Y
authors: Shiratori
authors: Seiji
authors: S
authors: Adachi
authors: Akihiro
authors: A
authors: Obora
authors: Masao
authors: M
authors: Takemura
authors: Masataka
authors: M
authors: Okuno
authors: Yoshihiro
authors: Y
authors: Shidoji
authors: Mitsuru
authors: M
authors: Seishima
authors: Yasutoshi
authors: Y
authors: Muto
authors: Hisataka
authors: H
authors: Moriwaki
mesh_terms: D000077556:Alitretinoin; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D006528:Carcinoma, Hepatocellular; D020169:Caspases / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D004268:DNA-Binding Proteins; D015536:Down-Regulation / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms; D008928:Mitochondria / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D019098:Telomerase / Q000235:genetics* / Q000378:metabolism*; D014212:Tretinoin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D000077556:Alitretinoin; D014212:Tretinoin; C034534:3,7,11,15-tetramethyl-2,4,6,10,14-hexadecapentaenoic acid; C509186:TERT protein, human; D019098:Telomerase; D020169:Caspases