ESE-1/EGR-1 pathway plays a role in tolfenamic acid-induced apoptosis in colorectal cancer cells.
ESE-1/EGR-1 pathway plays a role in tolfenamic acid-induced apoptosis in colorectal cancer cells.
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DOI：
10.1158/1535-7163.mct-08-0548
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发表时间：
2008-12
影响因子：
5.7
通讯作者：
Baek SJ
中科院分区：
文献类型：
--
作者：
Lee SH;Bahn JH;Choi CK;Whitlock NC;English AE;Safe S;Baek SJ
已知非甾体抗炎药（NSAID）可预防结直肠肿瘤发生。虽然NSAID的抗肿瘤作用主要是由于抑制环氧化酶（考克斯）活性，但越来越多的证据表明，COX非依赖性机制也可能发挥重要作用。早期生长反应-1（EGR-1）基因是立即早期基因家族的成员，已被鉴定为肿瘤抑制基因。托芬那酸（TA）是一种在胰腺癌模型中表现出抗癌活性的NSAID。在本研究中，我们研究了TA在人结直肠癌细胞中的抗癌活性。TA处理抑制细胞生长，诱导凋亡，半胱天冬酶活性和生物电阻抗测量。TA在转录水平诱导EGR-1的表达，EGR-1启动子的分析表明，位于-400和-394 bp的假定ETS结合位点（EBS）是TA激活所必需的。电泳迁移率变动试验（EMSA）和染色质免疫沉淀（ChIP）试验证实该序列与ETS家族蛋白ESE-1转录因子特异性结合。TA还促进了内源性和外源性ESE-1在结直肠癌细胞中向细胞核的易位，并且使用ESE-1 siRNA的基因沉默减弱了TA诱导的EGR-1表达和凋亡。EGR-1的过表达增加了细胞凋亡，降低了生物电阻抗，内源性EGR-1的沉默阻止了TA诱导的细胞凋亡。这些结果表明，通过增强核转位激活ESE-1介导TA诱导的EGR-1表达，其在细胞凋亡的激活中起关键作用。
Nonsteroidal anti-inflammatory drugs (NSAIDs) are known to prevent colorectal tumorigenesis. Although anti-tumor effects of NSAIDs are mainly due to inhibition of cyclooxgenase (COX) activity, there is increasing evidence that COX-independent mechanisms may also play an important role. The early growth response-1 (EGR-1) gene is a member of the immediate early gene family and has been identified as a tumor suppressor gene. Tolfenamic acid (TA) is an NSAID that exhibits anti-cancer activity in a pancreatic cancer model. In the present study, we investigated the anti-cancer activity of TA in human colorectal cancer cells. TA treatment inhibited cell growth and induced apoptosis as measured by caspase activity and bioelectric impedance. TA induced EGR-1 expression at the transcription level, and analysis of the EGR-1 promoter showed that a putative ETS binding site (EBS), located at −400 and −394 bp, was required for activation by TA. The electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay confirmed that this sequence specifically bound to the ETS family protein ESE-1 transcription factor. TA also facilitated translocation of endogenous and exogenous ESE-1 to the nucleus in colorectal cancer cells, and gene silencing using ESE-1 siRNA attenuated TA-induced EGR-1 expression and apoptosis. Overexpression of EGR-1 increased apoptosis and decreased bioelectrical impedance, and silencing of endogenous EGR-1 prevented TA-induced apoptosis. These results demonstrate that activation of ESE-1 via enhanced nuclear translocation mediates TA-induced EGR-1 expression, which plays a critical role in the activation of apoptosis.