title: Wnt/beta-catenin signaling in embryonic stem cell converted tumor cells.
abstract: BACKGROUND
  Embryonic stem cells (ESCs) are pluripotent stem cells and can form tumors containing cells from all three germ layers. Similarities between pluripotent stem cells and malignant tumor cells have been identified. The purpose of this study was to obtain ESCs-converted tumor cell lines and to investigate the mechanism of malignancy in pluripotent stem cells.
  
  
  METHODS
  Mouse ESCs were subcutaneously injected into nude mice to obtain tumors from which a tumor-like cell line (ECCs1) was established by culturing the cells in chemical-defined N2B27 medium supplied with two small molecular inhibitors CHIR99021 and PD0325901 (2i). The ECCs1 were then subcutaneously injected into nude mice again to obtain tumors from which another tumor-like cells line (ECCs2) was established in the same 2i medium. The malignant degree of ESCs, ECCs1 and ECCs2 was compared and the underlying mechanism involved in the malignancy development of ESCs was examined.
  
  
  RESULTS
  The three ESCs, ECCs1 and ECCs2 cell lines were cultured in the same 2i condition and showed some likeness such as Oct4-expression and long-term expansion ability. However, the morphology and the tumor-formation ability of the cell lines were different. We identified that ECCs1 and ECCs2 gradually acquired malignancy. Moreover, Wnt signaling-related genes such as CD133 and β-catenin expression were up-regulated and Frizzled related protein (FRP) was down-regulated during the tumor development of ESCs.
  
  
  CONCLUSIONS
  The two tumor-like cell lines ECCs1 and ECCs2 stand for early malignant development stage of ESCs and the ECCs2 was more malignant than the ECCs1. Moreover, we identified that Wnt/β-catenin signaling played an important role in the malignancy process of ESCs.
authors.affiliation: Laboratory of Viral and Gene Therapy, Eastern Hepatobiliary Surgical Hospital, The Second Military Medical University, Shanghai, China.
authors.forename: Xinrong
authors.initials: X
authors.lastname: Peng
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Qiaoling
authors.initials: Q
authors.lastname: Yan
authors.forename: Huajun
authors.initials: H
authors.lastname: Jin
authors.forename: Linfang
authors.initials: L
authors.lastname: Li
authors.forename: Qijun
authors.initials: Q
authors.lastname: Qian
authors.forename: Mengchao
authors.initials: M
authors.lastname: Wu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003470:Culture Media; D053595:Embryonic Stem Cells / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D015398:Signal Transduction; D051153:Wnt Proteins / Q000378:metabolism*; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D003470:Culture Media; D051153:Wnt Proteins; D051176:beta Catenin