title: Inhibition of NANOG/NANOGP8 downregulates MCL-1 in colorectal cancer cells and enhances the therapeutic efficacy of BH3 mimetics.
abstract: OBJECTIVE
  High levels of BCL-2 family members in colorectal carcinoma cause resistance to treatment. Inhibition of NANOG or its paralog NANOGP8 reduces the proliferation, stemness, and tumorigenicity of colorectal carcinoma cells. Our hypothesis was that inhibition of NANOG/NANOGP8 enhances the cytotoxic effect of BH3 mimetics targeting BCL-2 family members in colorectal carcinoma cells through reducing expression of MCL-1, a prosurvival BCL-2 protein.
  
  
  METHODS
  Lentiviral vector (LV) shRNA to NANOG (shNG-1) or NANOGP8 (shNp8-1) transduced colorectal carcinoma cells that were also exposed to the BH3 mimetics ABT-737 or ABT-199 in vivo in colorectal carcinoma xenografts and in vitro where proliferation, protein and gene expression, and apoptosis were measured.
  
  
  RESULTS
  Clone A and CX-1 were sensitive to ABT-737 and ABT-199 at IC50s of 2 to 9 μmol/L but LS174T was resistant with IC50s of 18 to 30 μmol/L. Resistance was associated with high MCL-1 expression in LS174T. LVshNG-1 or LVshNp8-1 decreased MCL-1 expression, increased apoptosis, and decreased replating efficiency in colorectal carcinoma cells treated with either ABT-737 or ABT-199 compared with the effects of either BH3 mimetic alone. Inhibition or overexpression of MCL-1 alone replicated the effects of LVshNG-1 or LVshNp8-1 in increasing or decreasing the apoptosis caused with the BH3 mimetic. The combination therapy inhibited the growth of LS174T xenografts in vivo compared with untreated controls or treatment with only LV shRNA or ABT-737.
  
  
  CONCLUSIONS
  Inhibition of NANOGP8 or NANOG enhances the cytotoxicity of BH3 mimetics that target BCL-2 family members. Gene therapy targeting the NANOGs may increase the efficacy of BH3 mimetics in colorectal carcinoma.
authors.affiliation: Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland.
authors.forename: Abid R
authors.initials: AR
authors.lastname: Mattoo
authors.affiliation: Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Espinoza
authors.affiliation: Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland. Cancer Diagnosis Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, Maryland. jessupj@mail.nih.gov.
authors.forename: J Milburn
authors.initials: JM
authors.lastname: Jessup
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D051023:BH3 Interacting Domain Death Agonist Protein / Q000235:genetics*; D001713:Biphenyl Compounds / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002460:Cell Line; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000235:genetics*; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics*; D057809:HEK293 Cells; D019073:HT29 Cells; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors*; D006801:Humans; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D064549:Myeloid Cell Leukemia Sequence 1 Protein / Q000235:genetics*; D000071317:Nanog Homeobox Protein; D009596:Nitrophenols / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D013449:Sulfonamides / Q000494:pharmacology; D023041:Xenograft Model Antitumor Assays
chemical_list: C501332:ABT-737; D051023:BH3 Interacting Domain Death Agonist Protein; D001713:Biphenyl Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D018398:Homeodomain Proteins; C579095:MCL1 protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D009596:Nitrophenols; D010879:Piperazines; D034741:RNA, Small Interfering; D013449:Sulfonamides; C579720:venetoclax