Takeda A, Shimizu S
Aichi Cancer Center Research Institute, Nagoya, Japan.
Endocrinology. 1988 Jul;123(1):258-63. doi: 10.1210/endo-123-1-258.
We have previously identified and characterized a 97K secretory glycoprotein (uterine secretory protein-1:USP-1) synthesized and secreted by rat uterine epithelial cells under estrogen stimulation. We now have analyzed the qualitative and quantitative effects of antiestrogens (tamoxifen and LY117018) on the induction of USP-1 biosynthesis when administered alone or combined with 17 beta-estradiol (E2). By radioimmune precipitation assay of [35S]methionine-labeled uterine luminal fluid proteins, it was shown that tamoxifen and LY117018 could weakly induce USP-1 compared with E2. Concomitant administration of either tamoxifen or LY117018 with E2 significantly diminished the effects of E2 on USP-1 induction. Hence, both tamoxifen and LY117018 possess agonistic as well as antagonistic properties affecting the induction of USP-1. These agonistic effects of antiestrogens were also evident from the presence of USP-1 in rat uterine epithelial cells treated with antiestrogens, as revealed by immunohistochemical staining. Sodium dodecylsulfate-polyacrylamide gel analysis of immunoprecipitable [35S]methionine-labeled protein revealed that USP-1 induced by tamoxifen is larger (110K) than that induced by estrogen or LY117018 (97K). Peptide-N-glycosidase treatment of USP-1 induced by E2 or tamoxifen removed asparagine-linked carbohydrate chains and resulted in the appearance of polypeptides with apparent mol wt of 91K and 105K, respectively. Thus, the higher mol wt of tamoxifen-induced USP-1 is not due to changes in asparagine-linked carbohydrates. Since LY117018 could not induce any qualitative change in the USP-1 molecule, tamoxifen may act on uterine epithelial cells through a different molecular mechanism than LY117018.
我们之前已鉴定并表征了一种97K分泌性糖蛋白（子宫分泌蛋白-1：USP-1），它是大鼠子宫上皮细胞在雌激素刺激下合成并分泌的。我们现在分析了抗雌激素药物（他莫昔芬和LY117018）单独给药或与17β-雌二醇（E2）联合给药时，对USP-1生物合成诱导的定性和定量影响。通过对[35S]甲硫氨酸标记的子宫腔液蛋白进行放射免疫沉淀分析，结果显示，与E2相比，他莫昔芬和LY117018对USP-1的诱导作用较弱。他莫昔芬或LY117018与E2同时给药，会显著减弱E2对USP-1诱导的作用。因此，他莫昔芬和LY117018都具有影响USP-1诱导的激动和拮抗特性。抗雌激素药物的这些激动作用在用抗雌激素药物处理的大鼠子宫上皮细胞中USP-1的存在情况中也很明显，免疫组织化学染色显示了这一点。对免疫沉淀的[35S]甲硫氨酸标记蛋白进行十二烷基硫酸钠-聚丙烯酰胺凝胶分析表明，他莫昔芬诱导的USP-1（110K）比雌激素或LY117018诱导的USP-1（97K）更大。用肽-N-糖苷酶处理E2或他莫昔芬诱导的USP-1，可去除天冬酰胺连接的碳水化合物链，分别产生表观分子量为91K和105K的多肽。因此，他莫昔芬诱导的USP-1较高的分子量并非由于天冬酰胺连接的碳水化合物的变化。由于LY117018不会在USP-1分子上引起任何定性变化，他莫昔芬可能通过与LY117018不同的分子机制作用于子宫上皮细胞。
