Shiozawa Tanri, Miyamoto Tsutomu, Kashima Hiroyasu, Nakayama Kohzo, Nikaido Toshio, Konishi Ikuo
Department of Obstetrics and Gynecology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan.
Oncogene. 2004 Nov 11;23(53):8603-10. doi: 10.1038/sj.onc.1207849.
To explore the mechanism of estrogen-induced growth of normal endometrium, the transactivation system of the cyclin D1 gene was analysed using cultured normal endometrial glandular cells. Estradiol (E2) treatment of cultured normal endometrial glandular cells induced upregulation of c-Jun, and then cyclin D1 proteins, followed by serial expressions of cyclins E, A and B1 proteins. Increase in the mRNA expression of cyclin D1 preceded the protein expression of cyclin D1 under E2 treatment. A luciferase assay using deletion constructs of the cyclin D1 promoter indicated that E2-induced increase in transcriptional activity was observed in reporters containing AP-1-binding site sequence, and that in the absence of E2, cotransfection of c-Jun also showed increase of transcriptional activity in the same reporters with AP-1 sequence. A gel shift assay using nuclear extract from E2-treated endometrial glandular cells and AP-1 sequences of the cyclin D1 promoter indicated specific binding between c-Jun protein and the promoter. Transfection of c-jun antisense oligonucleotides to the glandular cells resulted in the suppression of the E2-induced upregulation of cyclin D1 mRNA and protein. These findings suggest that E2-induced proliferation of normal endometrial glandular cells is initiated by transcriptional activation of cyclin D1 via binding of c-Jun to the AP-1 sequences.
为探究雌激素诱导正常子宫内膜生长的机制，利用培养的正常子宫内膜腺细胞分析了细胞周期蛋白D1基因的反式激活系统。用雌二醇（E2）处理培养的正常子宫内膜腺细胞可诱导c-Jun蛋白上调，随后细胞周期蛋白D1蛋白上调，接着依次出现细胞周期蛋白E、A和B1蛋白的表达。在E2处理下，细胞周期蛋白D1的mRNA表达增加先于其蛋白表达。使用细胞周期蛋白D1启动子缺失构建体进行的荧光素酶测定表明，在含有AP-1结合位点序列的报告基因中观察到E2诱导的转录活性增加，并且在没有E2的情况下，共转染c-Jun也显示相同的含AP-1序列的报告基因中的转录活性增加。使用来自E2处理的子宫内膜腺细胞的核提取物和细胞周期蛋白D1启动子的AP-1序列进行的凝胶迁移试验表明c-Jun蛋白与启动子之间存在特异性结合。将c-jun反义寡核苷酸转染到腺细胞中导致E2诱导的细胞周期蛋白D1 mRNA和蛋白上调受到抑制。这些发现表明，E2诱导的正常子宫内膜腺细胞增殖是通过c-Jun与AP-1序列结合，从而转录激活细胞周期蛋白D1启动的。
