title: Functional genomic analysis reveals cross-talk between peroxisome proliferator-activated receptor gamma and calcium signaling in human colorectal cancer cells.
abstract: Activation of PPARgamma in MOSER cells inhibits anchorage-dependent and anchorage-independent growth and invasion through Matrigel-coated transwell membranes. We carried out a longitudinal two-class microarray analysis in which mRNA abundance was measured as a function of time in cells treated with a thiazolidinedione PPARgamma agonist or vehicle. A statistical machine learning algorithm that employs an empirical Bayesian implementation of the multivariate HotellingT2 score was used to identify differentially regulated genes. HotellingT2 scores, MB statistics, and maximum median differences were used as figures of merit to interrogate genomic ontology of these targets. Three major cohorts of genes were regulated: those involved in metabolism, DNA replication, and migration/motility, reflecting the cellular phenotype that attends activation of PPARgamma. The bioinformatic analysis also inferred that PPARgamma regulates calcium signaling. This response was unanticipated, because calcium signaling has not previously been associated with PPARgamma activation. Ingenuity pathway analysis inferred that the nodal point in this cross-talk was Down syndrome critical region 1 (DSCR1). DSCR1 is an endogenous calcineurin inhibitor that blocks dephosphorylation and activation of members of the cytoplasmic component of nuclear factor of activated T cells transcription factors. Lentiviral short hairpin RNA-mediated knockdown of DSCR1 blocks PPARgamma inhibition of proliferation and invasion, indicating that DSCR1 is required for suppression of transformed properties of early stage colorectal cancer cells by PPARgamma. These data reveal a novel, heretofore unappreciated link between PPARgamma and calcium signaling and indicate that DSCR1, which has previously been thought to function by suppression of the angiogenic response in endothelial cells, may also play a direct role in transformation of epithelial cells.
authors.affiliation: Cancer Genomics Center, Texas Children's Hospital, Houston, Texas 77030, USA.
authors.forename: Craig R
authors.initials: CR
authors.lastname: Bush
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Havens
authors.forename: Brian M
authors.initials: BM
authors.lastname: Necela
authors.forename: Weidong
authors.initials: W
authors.lastname: Su
authors.forename: Lu
authors.initials: L
authors.lastname: Chen
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yanagisawa
authors.forename: Panos Z
authors.initials: PZ
authors.lastname: Anastasiadis
authors.forename: Rudy
authors.initials: R
authors.lastname: Guerra
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Luxon
authors.forename: E Aubrey
authors.initials: EA
authors.lastname: Thompson
mesh_terms: D020013:Calcium Signaling; D045744:Cell Line, Tumor; D002465:Cell Movement; D015179:Colorectal Neoplasms / Q000378:metabolism*; D019295:Computational Biology / Q000379:methods; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins; D023281:Genomics / Q000379:methods; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000502:physiology*; D016086:Lentivirus / Q000378:metabolism; D008954:Models, Biological; D009124:Muscle Proteins / Q000235:genetics* / Q000502:physiology*; D047495:PPAR gamma / Q000235:genetics* / Q000378:metabolism*; D010766:Phosphorylation; D015398:Signal Transduction
chemical_list: D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009124:Muscle Proteins; D047495:PPAR gamma; C108612:RCAN1 protein, human