title: A TALEN-based specific transcript knock-down of PIWIL2 suppresses cell growth in HepG2 tumor cell.
abstract: OBJECTIVE
  PIWIL2 is widely expressed in various tumours and implicated in playing a role in tumourigenesis. For a more thorough study of PIWIL2 functions in tumour cells, we aimed to establish PIWIL2-specific transcript knock-down/knockout HepG2 cell lines using transcription activator-like effector nuclease (TALEN) technology. Furthermore, we proposed to use the cell models to explore PIWIL2 functions in TGF-β signalling in HepG2 cells. HepG2s are human hepatocellular carcinoma cells.
  
  
  METHODS
  We established PIWIL2 knock-down or knock-out cell lines in HepG2 using TALEN technology. Next, we sought to use the cell line models to investigate effects of full length PIWIL2-specific transcripts in cell proliferation induced by TGF-β.
  
  
  RESULTS
  First, we established PIWIL2-specific transcript mono-allele and bi-allele knockout HepG2 cell lines. By using the cell line models, we found that specific transcript knockdown of full length PIWIL2 can suppress cell proliferation, while ectopic expression of PIWIL2 enhanced proliferation of HepG2 by suppressing the TGF-β pathway. Furthermore, we demonstrated that PIWIL2 can interact with HSP90 to prevent formation of HSP90-TβR complexes, which promote degradation of TβRs.
  
  
  CONCLUSIONS
  Taken together, our study revealed critical negative regulation of TGF-β signalling by PIWIL2 in HepG2 tumour cells, and provided an effective strategy to study specific gene transcript functions in cells.
authors.affiliation: Department of Medical Genetics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610000, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: W
authors.initials: W
authors.lastname: Hu
authors.forename: Y
authors.initials: Y
authors.lastname: Lu
authors.forename: S
authors.initials: S
authors.lastname: Jiang
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: D
authors.initials: D
authors.lastname: Tao
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.forename: Y
authors.initials: Y
authors.lastname: Ma
mesh_terms: D060565:Argonaute Proteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000235:genetics*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D015972:Gene Expression Regulation, Neoplastic; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics*; D034622:RNA Interference; D034741:RNA, Small Interfering; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D060565:Argonaute Proteins; D018841:HSP90 Heat-Shock Proteins; C486868:PIWIL2 protein, human; D034741:RNA, Small Interfering; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta