Determination of the Role of CBP- and p300-Mediated Wnt Signaling on Colonic Cells.
Determination of the Role of CBP- and p300-Mediated Wnt Signaling on Colonic Cells.
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DOI：
10.2196/resprot.5495
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发表时间：
2016-05-13
影响因子：
1.7
通讯作者：
Lazarova DL
中科院分区：
文献类型：
--
作者：
Bordonaro M;Lazarova DL
通过活性β-连环蛋白介导的Wnt信号通路是引发大多数人结直肠癌（CRC）病例的原因，我们先前已经表明，组蛋白脱乙酰酶抑制剂（HDACis）（如丁酸盐）对该通路的过度激活可诱导CRC细胞死亡。介导Wnt信号传导激活作用的一个重要细胞开关是β-连环蛋白与转录共激活因子cAMP反应元件结合（CREB）结合蛋白（CBP）和p300之间的关联的变化。CBP与β-连环蛋白的结合被认为激活了一组与细胞增殖相关的基因，而p300介导的Wnt遗传程序被认为促进了细胞分化。已经发现小分子试剂通过改变CBP和p300与β-连环蛋白的结合来调节CBP/p300 Wnt转录程序。ICG-001和ICG-427分别抑制CBP和p300介导的Wnt活性，而IQ-1阻止从CBP介导的Wnt活性转变为p300介导的Wnt活性。本提案的目的1旨在确定CBP和p300介导的Wnt信号传导在CRC细胞对HDACis的应答中的作用。目的2是确定CBP和p300在CRC细胞系中维持高和低Wnt组分中的作用。目的3将比较CBP和p300介导的Wnt活性对CRC发生和进展的影响。在目标1中，将用HDACis和ICG-001、ICG-427或IQ-1共处理细胞，并测量Wnt活性、凋亡、增殖、分化和CBP-或p300-β-连环蛋白结合的水平。该建议的目的2可能反映了在人类肿瘤中观察到的相似异质性，并且可能具有临床意义。目的3将使用大肠癌细胞系模型系统：正常结肠细胞系CCD-841 CoN、腺瘤细胞系LT 97、原发性结肠癌细胞系SW 480和淋巴结转移细胞系SW 620。细胞将用HDACis和小分子试剂处理，并如上所述进行测定。我们还将尝试使用CBP和p300介导的Wnt信号传导的变化来改变结肠细胞的细胞类型，改变LT 97腺瘤细胞系中CBP和p300介导的基因表达，以将腺瘤表型转变为更具CCD-841 CoN正常细胞或SW 480癌细胞特征的细胞。我们将使用微阵列分析，以确定负责这些CBP或p300介导的结肠肿瘤表型的变化的基因表达模式。这项研究的结果将导致未来更深入的项目，以进一步剖析CBP/p300 Wnt介导的转录程序在结肠肿瘤中的作用，重点是调节这些遗传程序以实现化学预防效果的方法。
The Wnt signaling pathway, mediated through active beta-catenin, is responsible for initiating the majority of cases of human colorectal cancer (CRC), and we have previously shown that hyperactivation of this pathway by histone deacetylase inhibitors (HDACis), such as butyrate, can induce the death of CRC cells. An important cellular switch that mediates the effects of Wnt-signaling activation is variation in the association between beta-catenin and the transcriptional coactivators cAMP response element binding (CREB) binding protein (CBP) and p300. Association of CBP with beta-catenin is thought to activate a set of genes linked to cell proliferation, while the p300-mediated Wnt genetic program is believed to promote cell differentiation. Small molecule agents have been discovered that modulate CBP/p300 Wnt transcriptional programs by altering the association of CBP and p300 to beta-catenin. ICG-001 and ICG-427 inhibit CBP- and p300-mediated Wnt activity, respectively, while IQ-1 prevents the shift from CBP-mediated to a p300-mediated Wnt activity. Aim 1 of this proposal is designed to determine the role of CBP- and p300-mediated Wnt signaling in the response of CRC cells to HDACis. Aim 2 is to determine the role of CBP and p300 in the maintenance of high- and low-Wnt fractions in CRC cell line. Aim 3 will compare the effects of CBP- and p300-mediated Wnt activity on CRC initiation and progression. In Aim 1, cells will be cotreated with HDACis and ICG-001, ICG-427, or IQ-1 and the levels of Wnt activity, apoptosis, proliferation, differentiation, and CBP- or p300-beta-catenin binding measured. Aim 2 of this proposal may mirror similar heterogeneity observed in human tumors and which may be of clinical significance. Aim 3 will use CRC cell line model systems of initiation and progression: the normal colon cell lines CCD-841CoN, the adenoma line LT97, the primary colon carcinoma cell line SW480, and the lymph node metastasis cell line SW620. Cells will be treated with HDACis and the small molecule agents, and assayed as described above. We will also attempt to use changes in CBP- and p300-mediated Wnt signaling to shift colonic cells between cell type, modifying CBP- and p300-mediated gene expression in the LT97 adenoma line to shift the adenoma phenotype to more characteristic of the CCD-841CoN normal cells, or the SW480 carcinoma cells. We will use microarray analyses to determine the patterns of gene expression responsible for these CBP- or p300-mediated changes in colonic neoplastic phenotype. The findings generated from this study will lead to future, more in-depth projects to further dissect the action of CBP/p300 Wnt–mediated transcriptional programs in colonic neoplasia, with an emphasis on methods to modulate these genetic programs for chemopreventive effect.