A stuby on expression mechanisms and functions of a novel adhesion molecule, trophinin

肌营养素是一种具有亲脂性的粘附分子。使用来自畸胎癌的HT-H细胞和来自子宫内膜癌的SNG-M（它们彼此粘附），通过表达克隆技术克隆该蛋白。鉴于滋养层蛋白在绒毛膜细胞、子宫内膜癌细胞中的表达可能是细胞增殖和进展的一个介导因子，我们首先研究了滋养层蛋白在早期胎盘、葡萄胎、绒毛膜癌和子宫内膜腺癌中的表达方式。应用抗滋养层蛋白功能区重组肽的单克隆抗体进行免疫组化研究，发现滋养层蛋白在早期胎盘和葡萄胎的合体滋养层细胞中有表达，而在绒毛膜癌和子宫内膜腺癌细胞中未见表达。就原位免疫反应的强度而言，在正常胎盘组织上看到的最强阳性反应在磨牙组织中减少，然后在绒毛膜癌中消失，提示滋养蛋白参与了恶性肿瘤细胞的转移活动，由于滋养蛋白被认为在囊胚与子宫内膜上皮的粘附或附着中起重要作用，并受月经周期的严格调节，第二阶段检测其在子宫内膜各期的表达变化。从人子宫内膜组织中提取的总RNA进行竞争性RT-PCR分析表明，滋养蛋白转录本的相对表达量在增殖晚期达到最高。这些发现表明，营养素的表达是由激素的变化，创造月经周期。

Trophinin is one of the adhesion molecules showing the homophilic manner. This protein was cloned by an expression cloning technique using HT-H cell derived from teratocarcinoma and SNG-M from uterine endometrial cancer, which adhere to each other. Since there is a possibility that trophinin could be a mediator for proliferation and progression of cells such as chorionic cells or endometrial cancer cells if they expressed it, we first invesdgated its expression manner on early placenta, hydatidiform mole, choriocarcimoma, and endometrial adenocarcinoma. The immunohistochemical investigation using the monoclonal antibody against the recombinant peptide corresponding to the functional domain in trophinin revealed that the immunoreacitve protein was seen in syncytiotrophoblasts of early placenta and hydatidiform mole, but not in choriocarcimoma or endometrial adenocarcinoma cells. Regarding to an intensity of the immunoreactivity in situ, the strongest positive reaction seen on the normal placental tissue was decreased in molar tissue, then disappeared in choriocarcinoma, suggesting that trophinin is involved with the metastatic activity of the malignant cells.Since trophinin is thought to divide an important role of the adhesion or attachment between blastcyst and endometrial epithelium and to be strictly regulated due to the menstrual cycles, we secondly examined the changes of its expression in various phases of endometrium. The analysis by competitive RT-PCR using total RNA taken from human endometrial tissue showed that the relative expression of trophinin transcripts reached the highest at the late proliferative phase. These findings suggest that the expression of trophinin is regulated by the hormonal changes which create the menstrual cycle.