The mechanism of SP1/p300 complex promotes proliferation of multiple myeloma cells through regulating IQGAP1 transcription
The mechanism of SP1/p300 complex promotes proliferation of multiple myeloma cells through regulating IQGAP1 transcription
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SP1/p300复合物通过调节IQGAP1转录促进多发性骨髓瘤细胞增殖的机制
DOI：
10.1016/j.biopha.2019.109434
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发表时间：
2019-11-01
影响因子：
7.5
通讯作者：
Ma, Yongyong
中科院分区：
文献类型：
--
作者：
Jin, Zhouxiang;Zhou, Shujuan;Ma, Yongyong
本课题组前期研究首次发现MM细胞中IQGAP 1基因过表达，激活Ras/Raf/MEK/ERK信号通路。但IQGAP 1过表达及其基因转录调控的机制尚不清楚。本研究旨在探讨IQGAP 1基因在骨髓瘤细胞中的过表达及其转录调控机制。通过生物信息学分析和预测，预测并筛选出可能为IQGAP 1上游调控因子的转录因子Sp1。将siRNA-IQGAP 1转染骨髓瘤细胞后，检测细胞增殖、细胞周期及下游ERK 1/2和p-ERK 1/2蛋白的表达。分别抑制或过表达Sp1和p300后，检测Sp1、p300、IQGAP 1、p-ERK 1/2和ERK 1/2的表达。采用双荧光素酶报告系统检测IQGAP 1基因启动子的活性。用CHIP检测Sp1和IQGAP 1启动子区的结合，用CO-IP检测Sp1和p300的相互作用，检测骨髓瘤患者Sp1、p300和IQGAP 1的mRNA表达水平，并进行相关性分析。结果显示，IQGAP 1-siRNA能抑制细胞增殖、细胞周期、IQGAP 1表达及ERK 1/2蛋白磷酸化。抑制Sp1或p300可下调ERK 1/2和IQGAP 1的表达，过表达Sp1或p300可上调ERK 1/2和IQGAP 1的表达，Sp1和p300对IQGAP 1有正调控作用，过表达Sp1或p300可显著提高IQGAP 1基因启动子的活性。转录因子Sp1在IQGAP 1启动子区起调节作用。在骨髓瘤细胞中，Sp1与p300之间存在相互作用。MM组织中Sp1、IQGAP 1和p300的mRNA表达水平呈正相关。总之，IQGAP 1是MM细胞增殖所必需的，并且Sp1/p300复合物的转录调节IQGAP 1基因的表达。
Our previous research had firstly shown that MM cells overexpressed IQGAP1 gene and activated Ras/Raf/MEK/ERK pathway. But the mechanism of IQGAP1 overexpression and IQGAP1 gene transcription regulation remains uncertain. The mechanism of IQGAP1 overexpression and transcriptional regulation of IQGAP1 gene in myeloma cells was explored in the study. Through bioinformatics analysis and prediction we predicted and screened transcription factor Sp1 as a possible upstream regulator of IQGAP1.The proliferation, cell cycle and downstream ERK1/2 and p-ERK1/2 proteins were detected after siRNA-IQGAP1 was transfected to myeloma cells. The expression of Sp1, p300, IQGAP1, p-ERK1/2 and ERK1/2 were detected after Sp1 and p300 were inhibited or overexpressed respectively. The dual-luciferase reporter system was used to detect the activity of IQGAP1 gene promoter. CHIP was used to detect the binding of the Sp1 and IQGAP1 promoter regions.CO-IP was used to explore the interaction between Sp1 and p300.The mRNA expression levels of Sp1, p300 and IQGAP1 of the myeloma patients were detected, and the correlation analysis of their mRNA expression levels were carried out. The results showed IQGAP1-siRNA inhibits cell proliferation, cell cycle, IQGAP1 expression and phosphorylation of ERK1/2 protein. Inhibition of Sp1 or p300 down-regulated ERK1/2 and IQGAP1 expression; overexpression of Sp1 or p300 up-regulated ERK1/2 and IQGAP1 expression; Sp1 and p300 had a positive regulation effect on IQGAP1.Over expression of Sp1 or p300 significantly increased activity of IQGAP1 gene promoter. The transcription factor Sp1 plays a regulatory role in the IQGAP1 promoter region. There is an interaction between Sp1 and p300 in myeloma cells. The mRNA expression levels of Sp1, IQGAP1 and p300 in MM samples showed a positive correlation. In summary IQGAP1 is required for cell proliferation in MM cells, and the transcription of Sp1/p300 complex regulates expression of IQGAP1 gene.