title: Long-term culture following ES-like gene-induced reprogramming elicits an aggressive phenotype in mutated cholangiocellular carcinoma cells.
abstract: BACKGROUND
  We recently reported that gastrointestinal (GI) cancer cells can be reprogrammed to a pluripotent state by the ectopic expression of defined embryonic stem (ES)-like transcriptional factors. The induced pluripotent cancer (iPC) cells from GI cancer were sensitized to chemotherapeutic agents and differentiation-inducing treatment during a short-term culture, although a phenotype induced by long-term culture needs to be studied.
  
  
  METHODS
  A long-term cultured (Lc)-iPC cells were produced in GI cancer cell lines by virus-mediated introduction of four ES-like genes-c-MYC, SOX2, OCT3/4, and KLF4-followed by a culture more than three months after iPC cells induction. An acquired state was studied by expression of immature-related surface antigens, Tra-1-60, Tra-1-81, Tra-2-49, and Ssea-4; and epigenetic trimethyl modification at lysine 4 of histone H3. Sensitivity to chemotherapeutic agents and tumorigenicity were studied in Lc-iPC cells.
  
  
  RESULTS
  Whereas the introduction of defined factors of iPC cells once induced an immature state and sensitized cells to therapeutic reagents, the endogenous expression of the ES-like genes except for activated endogenous c-MYC was down-regulated in a long-term culture, suggesting a high magnitude of the reprogramming induction by defined factors and the requirement of therapeutic maintenance in Lc-iPC cells from cholangiocellular carcinoma HuCC-T1 cells, which harbor TP53(R175H) and KRAS(G12D). The Lc-iPC cells showed resistance to 5-fluorouracil in culture, and high tumorigenic ability with activated endogenous c-MYC in immunodeficient mice.
  
  
  CONCLUSIONS
  The Lc-iPC cells from HuCC-T1 might be prone to an undesirable therapeutic response because of an association with the activated endogenous c-MYC. To consider the possible therapeutic approach in GI cancer, it would be necessary to develop a predictive method for evaluating the improper reprogramming-associated aggressive phenotype of iPC cells.
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Yamadaoka 2-2, Suita, Osaka 565-0871, Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Nagai
authors.forename: Hideshi
authors.initials: H
authors.lastname: Ishii
authors.forename: Norikatsu
authors.initials: N
authors.lastname: Miyoshi
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Hoshino
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Saito
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Sato
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Tomimaru
authors.forename: Shogo
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nagano
authors.forename: Mitsugu
authors.initials: M
authors.lastname: Sekimoto
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Doki
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D001650:Bile Duct Neoplasms / Q000235:genetics / Q000473:pathology*; D001653:Bile Ducts, Intrahepatic / Q000378:metabolism / Q000473:pathology*; D018929:Cell Culture Techniques; D049109:Cell Proliferation / Q000187:drug effects; D065150:Cellular Reprogramming / Q000235:genetics; D018281:Cholangiocarcinoma / Q000235:genetics / Q000473:pathology*; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D053595:Embryonic Stem Cells / Q000378:metabolism; D044127:Epigenesis, Genetic; D005472:Fluorouracil / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D000090062:Kruppel-Like Factor 4; D051379:Mice; D016513:Mice, SCID; D009154:Mutation; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics*; D015533:Transcriptional Activation
chemical_list: D000964:Antimetabolites, Antineoplastic; C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D016271:Proto-Oncogene Proteins c-myc; D005472:Fluorouracil