Bush Craig R, Havens Jennifer M, Necela Brian M, Su Weidong, Chen Lu, Yanagisawa Masahiro, Anastasiadis Panos Z, Guerra Rudy, Luxon Bruce A, Thompson E Aubrey
Cancer Genomics Center, Texas Children's Hospital, Houston, Texas 77030, USA.
J Biol Chem. 2007 Aug 10;282(32):23387-401. doi: 10.1074/jbc.M702708200. Epub 2007 Jun 12.
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.
在MOSER细胞中，过氧化物酶体增殖物激活受体γ（PPARγ）的激活可抑制锚定依赖性和非锚定依赖性生长以及通过基质胶包被的Transwell膜的侵袭。我们进行了一项纵向两类微阵列分析，其中在噻唑烷二酮PPARγ激动剂或溶剂处理的细胞中，将mRNA丰度作为时间的函数进行测量。使用一种采用多元Hotelling T2评分的经验贝叶斯实现的统计机器学习算法来鉴定差异调节基因。Hotelling T2评分、MB统计量和最大中位数差异用作评估这些靶标的基因组本体的品质因数。有三大类基因受到调控：那些参与代谢、DNA复制和迁移/运动的基因，反映了伴随PPARγ激活的细胞表型。生物信息学分析还推断PPARγ调节钙信号传导。这种反应出乎意料，因为钙信号传导以前未与PPARγ激活相关联。通路分析推断这种相互作用中的节点是唐氏综合征关键区域1（DSCR1）。DSCR1是一种内源性钙调神经磷酸酶抑制剂，可阻断活化T细胞核因子转录因子细胞质成分成员的去磷酸化和激活。慢病毒短发夹RNA介导的DSCR1敲低可阻断PPARγ对增殖和侵袭的抑制作用，表明DSCR1是PPARγ抑制早期结直肠癌细胞转化特性所必需的。这些数据揭示了PPARγ与钙信号传导之间一种新的、以前未被认识的联系，并表明DSCR1以前被认为通过抑制内皮细胞中的血管生成反应发挥作用，也可能在上皮细胞转化中起直接作用。
