Tynan Sharon, Pacia Emmanuel, Haynes-Johnson Donna, Lawrence Danielle, D'Andrea Michael R, Guo Jian-Zhong, Lundeen Scott, Allan George
Reproductive Therapeutics, Johnson & Johnson Pharmaceutical Research and Development, L.L.C., Room B-115, 1000 US Route 202 South, P.O. Box 300, Raritan, New Jersey 08869, USA.
Endocrinology. 2005 Mar;146(3):1066-73. doi: 10.1210/en.2004-1304. Epub 2004 Nov 24.
Deleted in malignant brain tumors 1 (DMBT1) is a candidate suppressor of malignancies of the brain, lung, gut, and breast. We have been studying gene expression in the uterus in the presence of estrogens and their antagonists. Here, we show that DMBT1 RNA levels are robustly increased by estrogen treatment in the uteri of ovariectomized monkeys and rats. In monkeys, the progestin antagonist mifepristone inhibits estrogen-dependent uterine proliferation. As determined by a microarray experiment and quantitative analysis of RNA levels, mifepristone inhibited estrogenic induction of DMBT1. DMBT1 was not expressed in intact monkeys that were treated with a gonadotropin agonist to suppress steroidogenesis. An in vitro transfection study with human DMBT1 promoter constructs showed that an Alu site approximately 3000 nucleotides upstream of the gene mediates estrogenic regulation. Surprisingly, the estrogen antagonists tamoxifen, raloxifene, and ICI 182,780 also induced gene expression via this Alu site. Rodents represent a more convenient model system for studying uterine biology than monkeys. In rats, uterine DMBT1 RNA levels were dramatically up-regulated by estrogen. Consistent with the transfection study, tamoxifen and raloxifene increased DMBT1 RNA levels in vivo, but ICI 182,780 inhibited an estrogen-induced increase. Immunohistochemical studies showed that DMBT1 is specifically induced in glandular and luminal epithelia of the rat endometrium. Our experiments establish that DMBT1 is an estrogen-responsive gene with a possible role in endometrial proliferation or differentiation, and they have implications for the putative tumor suppressive and mucosal protective functions of DMBT1 in the uterus.
恶性脑肿瘤缺失基因1（DMBT1）是脑、肺、肠道和乳腺恶性肿瘤的候选抑制基因。我们一直在研究雌激素及其拮抗剂存在时子宫中的基因表达。在此，我们表明，雌激素处理可使去卵巢猴子和大鼠子宫中的DMBT1 RNA水平显著升高。在猴子中，孕激素拮抗剂米非司酮可抑制雌激素依赖性子宫增殖。通过微阵列实验和RNA水平定量分析确定，米非司酮抑制雌激素对DMBT1的诱导作用。用促性腺激素激动剂抑制类固醇生成的完整猴子中未检测到DMBT1表达。用人DMBT1启动子构建体进行的体外转染研究表明，该基因上游约3000个核苷酸处的一个Alu位点介导雌激素调节。令人惊讶的是，雌激素拮抗剂他莫昔芬、雷洛昔芬和ICI 182,780也通过该Alu位点诱导基因表达。与猴子相比，啮齿动物是研究子宫生物学更方便的模型系统。在大鼠中，雌激素可显著上调子宫DMBT1 RNA水平。与转染研究一致，他莫昔芬和雷洛昔芬在体内增加了DMBT1 RNA水平，但ICI 182,780抑制了雌激素诱导的增加。免疫组织化学研究表明，DMBT1在大鼠子宫内膜的腺上皮和腔上皮中特异性诱导表达。我们的实验证实，DMBT1是一个雌激素反应基因，可能在子宫内膜增殖或分化中发挥作用，这对DMBT1在子宫中假定的肿瘤抑制和黏膜保护功能具有重要意义。
