Cyclooxygenase-2 induction and transforming growth factor beta growth inhibition in rat intestinal epithelial cells.
Cyclooxygenase-2 induction and transforming growth factor beta growth inhibition in rat intestinal epithelial cells.
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发表时间：
1997-04
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通讯作者：
H. Sheng;J. Shao;Hooton Eb;M. Tsujii;R. Dubois;R. Beauchamp
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作者：
H. Sheng;J. Shao;Hooton Eb;M. Tsujii;R. Dubois;R. Beauchamp
永久转导前列腺素内过氧化物合成酶2(又称环氧合酶-2；COX-2)基因的大鼠肠上皮细胞(RIE-1)表现为细胞周期蛋白D1水平降低，CDK4相关激酶活性降低，G1期细胞周期延迟，表现出与转化生长因子-β(TGF-β)处理后相似的表型。在目前的研究中，我们发现在亲代RIE-1细胞中加入转化生长因子-β1(RIE-P)可以迅速诱导COX-2mRNA和蛋白的表达。加入转化生长因子-β1后6h，COX-2蛋白水平逐渐升高，并达到峰值。转染COX-2反义表达载体(RIE-AS细胞)的RIE细胞中，TGF-β1诱导的COX-2蛋白表达下降了90%以上。与RIE-P细胞不同，加入转化生长因子-β1并不能减少RIE-AS细胞中丰富的细胞周期蛋白D1的表达。经转化生长因子-β1处理后，RIE-P细胞的[~3H]胸腺嘧啶核苷掺入峰值降低60%，G1/S期转变延迟至少4h。反之，RIE-AS细胞在16h进入S时相，且不受转化生长因子-β1处理的影响。在巨细胞病毒启动子/增强子的转录调控下，将细胞周期蛋白D1cDNA导入COX-2过表达细胞(RIE-S)，可使进入S相的时间缩短至少4h，并提高[~3H]胸腺嘧啶核苷掺入的峰值水平。综上所述，这些结果表明，转化生长因子-β1在mRNA和蛋白水平上都强烈地诱导了环氧合酶-2的表达，提示环氧合酶-2的诱导可能与转化生长因子-β1引起的大鼠肠上皮细胞周期蛋白D1表达下调和细胞生长抑制有关。
Rat intestinal epithelial cells (RIE-1) permanently transfected with the prostaglandin endoperoxide synthase 2 (also referred to as cyclooxygenase-2; COX-2) gene exhibit decreased cyclin D1 levels, decreased cdk4-associated kinase activity, and delayed G1 cell cycle progression, which represents a phenotype similar to that which follows transforming growth factor beta (TGF-beta) treatment. In the current study, we have found that addition of TGF-beta 1 to the parental RIE-1 cells (designated RIE-P) caused a rapid induction of COX-2 mRNA and protein. COX-2 protein levels progressively increased and reached peak levels 6 h after TGF-beta 1 addition. Cyclin D1 was decreased by 74% at 6 h and was undetectable 24 h after addition of TGF-beta 1. In RIE cells transfected with the COX-2 antisense expression vector (RIE-AS cells), TGF-beta 1 induction of COX-2 protein was reduced greater than 90%. Addition of TGF-beta 1 did not reduce the abundant cyclin D1 protein expression in the RIE-AS cells, unlike the effect in RIE-P cells. TGF-beta 1 treatment reduced peak [3H]thymidine incorporation by 60% and delayed G1/S-phase transition by at least 4 h in the RIE-P cells. In contrast, S-phase entry occurred at 16 h in RIE-AS cells and was not altered by TGF-beta 1 treatment. Restoration of cyclin D1 expression by transfection of the cyclin D1 cDNA under transcriptional control of the cytomegalovirus promoter/enhancer in the COX-2-overexpressing (RIE-S) cells decreased the time required for S-phase entry by at least 4 h and increased the peak level of [3H]thymidine incorporation. Taken together, the results demonstrate that TGF-beta 1 strongly induces COX-2 at both the mRNA and protein levels and suggest that this induction of COX-2 is involved in the down-regulation of cyclin D1 and inhibition of cell growth caused by TGF-beta 1 in rat intestinal epithelial cells.