title: BET protein inhibitor JQ1 inhibits growth and modulates WNT signaling in mesenchymal stem cells.
abstract: BACKGROUND
  Efficacy and safety of anticancer drugs are traditionally studied using cancer cell lines and animal models. The thienodiazepine class of BET inhibitors, such as JQ1, has been extensively studied for the potential treatment of hematological malignancies and several small molecules belonging to this class are currently under clinical investigation. While these compounds are well known to inhibit cancer cell growth and cause apoptosis, their effects on stem cells, particularly mesenchymal stem cells (MSCs), which are important for regeneration of damaged cells and tissues, are unknown. In this study we employed umbilical cord derived MSCs as a model system to evaluate the safety of JQ1.
  
  
  METHODS
  Cord derived MSCs were treated with various doses of JQ1 and subjected to cell metabolic activity, apoptosis, and cell cycle analyses using MTT assay, Annexin-V/FITC and PI staining, and flow cytometry, respectively. The effect of JQ1 on gene expression was determined using microarray and quantitative real-time reverse transcriptase polymerase chain reaction analysis. Furthermore, protein expression of apoptotic and neuronal markers was carried out using western blot and immunostaining, respectively.
  
  
  RESULTS
  Our results showed that JQ1 inhibited cell growth and caused cell cycle arrest in G1 phase but did not induce apoptosis or senescence. JQ1 also down-regulated genes involved in self-renewal, cell cycle, DNA replication, and mitosis, which may have negative implications on the regenerative potential of MSCs. In addition, JQ1 interfered with signaling pathways by down regulating the expression of WNT, resulting in limiting the self-renewal. These results suggest that anticancer agents belonging to the thienodiazepine class of BET inhibitors should be carefully evaluated before their use in cancer therapy.
  
  
  CONCLUSIONS
  This study revealed for the first time that JQ1 adversely affected MSCs, which are important for repair and regeneration. JQ1 specifically modulated signal transduction and inhibited growth as well as self-renewal. These findings suggest that perinatal MSCs could be used to supplement animal models for investigating the safety of anticancer agents and other drugs.
authors.affiliation: Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. soalgham@oakland.eduff.|OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA. soalgham@oakland.eduff.
authors.forename: Saeed
authors.initials: S
authors.lastname: Alghamdi
authors.affiliation: Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. irfan_khan2009@yahoo.com.|OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA. irfan_khan2009@yahoo.com.
authors.forename: Irfan
authors.initials: I
authors.lastname: Khan
authors.affiliation: Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. nbeeravo@oakland.edu.|OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA. nbeeravo@oakland.edu.
authors.forename: Naimisha
authors.initials: N
authors.lastname: Beeravolu
authors.affiliation: Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. cmmckee@oakland.edu.|OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA. cmmckee@oakland.edu.
authors.forename: Christina
authors.initials: C
authors.lastname: McKee
authors.affiliation: Beaumont Health System, Royal Oak, MI, 48073, USA. Bryan.Thibodeau@beaumont.org.
authors.forename: Bryan
authors.initials: B
authors.lastname: Thibodeau
authors.affiliation: OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA. George.Wilson@beaumont.edu.|Beaumont Health System, Royal Oak, MI, 48073, USA. George.Wilson@beaumont.edu.
authors.forename: George
authors.initials: G
authors.lastname: Wilson
authors.affiliation: Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. chaudhry@oakland.edu.|OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA. chaudhry@oakland.edu.
authors.forename: G Rasul
authors.initials: GR
authors.lastname: Chaudhry
mesh_terms: D017209:Apoptosis; D001381:Azepines / Q000494:pharmacology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D015870:Gene Expression; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000378:metabolism*; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D016601:RNA-Binding Proteins / Q000037:antagonists & inhibitors; D014157:Transcription Factors / Q000037:antagonists & inhibitors; D014230:Triazoles / Q000494:pharmacology*; D060449:Wnt Signaling Pathway / Q000187:drug effects*; D000092468:Bromodomain Containing Proteins
chemical_list: D001381:Azepines; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D017346:Protein Serine-Threonine Kinases; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D014230:Triazoles; C561695:(+)-JQ1 compound; C098415:BRD2 protein, human; D000092468:Bromodomain Containing Proteins; C109106:BRD3 protein, human; C441289:BRD4 protein, human; C109570:BRDT protein, human
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