Trophoblastic tumors: ultrastructural comparison of choriocarcinoma and placental-site trophoblastic tumor

Ten trophoblastic tumors, including seven classical choriocarcinomas, two choriocarcinomas with atypical histology, and one placental-site trophoblastic tumor (PSTT), were studied to compare their fine structural features. Ultrastructurally, the classical choriocarcinomas showed well-defined cytotrophoblasts and syncytiotrophoblasts. The cytotrophoblasts were primitive epithelial cells, while the syncytiotrophoblasts were complex cells with multiple nuclei and dense cytoplasm containing dilated endoplasmic reticulum, lysosomes, vesicles, and tonofilaments. The syncytiotrophoblast cell membranes often contained numerous microvilli. In the choriocarcinomas, scattered intermediate trophoblasts showed features transitional between the cytotrophoblasts and the syncytiotrophoblasts, with moderately complex cytoplasm containing some of the organelles found in the syncytiotrophoblasts. Histologically, the atypical choriocarcinomas showed a predominance of mononucleate and binucleate cells and indistinct syncytiotrophoblasts. Ultrastructurally, these atypical tumors were composed largely of intermediate trophoblasts, yet contained scattered syncytiotrophoblasts with microvilli in compressed aggregates. The PSTT was composed primarily of intermediate trophoblasts that contained prominent paranuclear filaments not seen in the intermediate trophoblasts of the choriocarcinomas. Rare cells resembling syncytiotrophoblasts were found in the PSTT, but no cytotrophoblasts were observed. Immunoreactivity for human chorionic gonadotropin and human placental lactogen was found in the intermediate trophoblasts and syncytiotrophoblasts of both the choriocarcinomas and the PSTT, demonstrating functional homology between these tumors despite some ultrastructural differences. These results demonstrate ultrastructural features of trophoblastic cells that correlate with the morphologic diversity seen in these tumors by light microscopy. Furthermore, the comparisons suggest that the PSTT is composed of a distinct form of intermediate trophoblast that appears to reflect its origin from the extravillous trophoblast.     

The expression and localization of neutral endopeptidase 24.11/CD10 in human gestational trophoblastic diseases

Neutral endopeptidase 24.11 (NEP)/CD10 is a cell-surface peptidase that hydrolyzes various bioactive peptides. NEP is distributed in both normal and neoplastic cells and plays a functional role by modulating cellular responses to peptide substrates. Recently, NEP has been shown to be expressed in normal placental trophoblasts, suggesting its physiological role during pregnancy. In the present study, we investigated the expression of NEP in hyperplastic and anaplastic trophoblasts in gestational trophoblastic diseases (GTDs). Flow cytometric analysis demonstrated that NEP was expressed in all choriocarcinoma cell lines examined. The NEP enzyme activity in these cell lines correlated with cell-surface protein levels and was abolished by the NEP inhibitor phosphoramidon. On immunoblot analysis, NEP protein was detected in both hydatidiform mole and choriocarcinoma tissues as a double band of 95 and 100 kDa similar to that of the normal placental tissues. Immunohistochemical analysis revealed that NEP was present on syncytiotrophoblasts, while no or very faint NEP immunoreactivity was observed on cytotrophoblasts in the normal placenta. Similarly, NEP in hydatidiform mole and invasive mole was localized on the membrane of syncytiotrophoblasts, but not on hyperplastic cytotrophoblasts. In contrast, in choriocarcinoma, NEP was highly expressed not only on syncytiotrophoblastic cells but also on invading anaplastic cytotrophoblasts. In addition, NEP was also expressed on intermediate trophoblasts in placental site trophoblastic tumors. In summary, this is the first study demonstrating the expression of NEP/CD10 in GTDs. The differential localization of NEP among various trophoblastic tumors suggests that NEP may play a functional role in the regulation of trophoblast transformation and human chorionic gonadotropin secretion.     

Human Trophoblast Cell Adhesion to Extracellular Matrix Protein,Entactin

PROBLEM: Trophoblast interaction with endometrial extracellular matrix (ECM) is crucial during human embryo implantation and placentation. Entactin, a ubiquitous basement membrane glycoprotein, plays a central role in ECM assembly, cell attachment, and chemotaxis. The present study was conducted to examine the possible role of entactin in promoting human trophoblast adhesion. METHODS: Using an extended life span first trimester trophoblast cell line HTR-8/SVneo (HTR) and a cell adhesion assay, we measured the adherence of human first trimester trophoblasts to recombinant entactin and its domains. Also, we used flow cytometry and indirect immunofluorescence to detect the presence of integrins that may be involved in human trophoblast-entactin interaction; these methods were used to analyze HTR cells, as well as tissue sections and freshly isolated human trophoblasts from first trimester and term placenta. RESULTS: We found that first trimester trophoblast cells were highly adherent to entactin and its E and G2 domains but not to G1 or G3 domains. Using indirect immunofluorescence and flow cytometry, we found that both β1 and β3 integrin subunits were expressed on the surface of HTR trophoblast cells adhering to entactin; in contrast, β2 and β4 integrin subunits were not detected. In addition, we found that αvβ3 was expressed on freshly isolated villous cytotrophoblasts and cytotrophoblast and syncytiotrophoblasts in tissue sections from term placenta. The β3 integrin subunit was expressed in cytotrophoblasts and syncytiotrophoblasts in villi of first trimester placental tissue sections. CONCLUSION: Recombinant entactin promotes human trophoblast cell adhesion through both its E and G2 domains and these specific adhesive interactions may be mediated by β1 and/or β3 class integrins.     

Plasminogen activator inhibitor types 1 and 2 in human trophoblasts. PAI-1 is an immunocytochemical marker of invading trophoblasts

Trophoblast implantation, vascular remodeling, and maintenance of intervillous blood flow may depend on the regulated production of proteolytic enzymes such as plasminogen activator (PA). Since the functional activity of plasminogen activators is determined not only by the quantity of protease but also by levels of specific plasminogen activator inhibitors (PAI), we examined trophoblasts both in vitro and in vivo for the presence of two PAIs, PAI-1 and PAI-2. Cytotrophoblasts were isolated from first trimester or term placentae, cultured, and immunocytochemically stained using specific anti-PAI antibodies. The antiserum against PAI-1 demonstrated prominent cell-surface staining and some cytoplasmic staining. The antiserum generated against PAI-2 revealed a cytoplasmic localization, with some trophoblasts staining intensely, whereas others had no apparent reactivity. We also found that cultured cytotrophoblasts contain the mRNAs for PAI-1 and PAI-2. Immunohistochemical analysis of tissue sections from 8-, 16-, and 40-week implantation sites using antisera against PAI-1 demonstrated weak staining of villous syncytiotrophoblasts but prominent cytoplasmic staining of trophoblasts invading the decidua and myometrium. Antisera against PAI-2 stained the cytoplasm of villous syncytiotrophoblasts, but no staining was evident in villous cytotrophoblasts or in invading trophoblasts. We conclude that 1) human trophoblasts can express both PAI-1 and PAI-2 in vitro and in vivo and 2) prominent PAI-1 immunostaining defines invading trophoblasts, whereas PAI-2 is the predominant PAI accumulated in villous syncytiotrophoblasts. Thus, the various trophoblast forms have distinctive patterns of PAI expression.     

Src family kinases play multiple roles in differentiation of trophoblasts from human term placenta

Tyrosine phosphorylation plays a major role in controlling many biological processes in different cell types. Src family kinases (SFKs) are one of the most studied groups of tyrosine kinases and can mediate a variety of signalling pathways. However, little is known about the expression of SFKs in human term placenta and their implication in trophoblast differentiation. Therefore, we examined the expression profile of SFK members over time in culture and their implication in differentiation. In vitro , freshly isolated cytotrophoblast cells, cultured in 10% fetal bovine serum (FBS), spontaneously aggregate and fuse to form multinucleated cells that resemble phenotypically mature syncytiotrophoblasts, that concomitantly produce human chorionic gonadotropin (hCG) and human placental lactogen (hPL). In this study, we showed that trophoblasts expressed all SFK members and some of them are expressed as different splice variants. Moreover, using real-time PCR, this study showed two different expression profiles of SFKs in human trophoblasts during culture. In addition, the protein level and phosphorylation status of Src were evaluated using specific antibodies. Src was rapidly phosphorylated at Tyr-416 and dephosphorylated at Tyr-527 after FBS addition. Surprisingly, inhibition of SFKs by 4-amino-5-(4-chlorophenyl)-7-( t -butyl) pyrazolo[3,4-d] pyrimidine (PP2) or herbimycin A had different effects on trophoblast differentiation. While herbimycin A inhibited morphological and hormonal differentiation, PP2 stimulated hormonal differentiation and inhibited cell adhesion and spreading with no effect on cell fusion. In summary, this study showed that SFKs play different roles in trophoblast differentiation, probably depending on SFK members activated. Thus, this study increases our knowledge and understanding of pathology related to impaired trophoblast differentiation such as pre-eclampsia and trophoblast neoplasm.     

ERK1/2 and p38 regulate trophoblasts differentiation in human term placenta

Mitogen-activated protein kinases (MAPKs) control many cellular events from complex programmes, such as embryogenesis, cell differentiation and proliferation, and cell death, to short-term changes required for homeostasis and acute hormonal responses. However, little is known about expression and activation of classical MAPKs, extracellular signal-regulated kinase1/2 (ERK1/2) and p38 in human placenta. Therefore, we examined the expression of ERK1/2 and p38 in trophoblasts from human term placenta, and their implication in differentiation. In vitro , freshly isolated cytotrophoblast cells, cultivated in 10% fetal bovine serum (FBS), spontaneously aggregate and fuse to form multinucleated cells that phenotypically resemble mature syncytiotrophoblasts, that concomitantly produce human chorionic gonadotropin (hCG) and human placental lactogen (hPL). This study shows that the level of ERK1/2 and p38 decreases with increasing days of culture, to reach an undetectable level after 5 days of culture. Moreover, pretreatment of cells with an ERK1/2-specific inhibitor (PD98059) and/or a p38-specific inhibitor (SB203580) suppressed trophoblast differentiation. Our results also demonstrate that the p38 pathway is highly solicited as compared to the ERK1/2 pathway in the differentiation process. Furthermore, ERK1/2 and p38 are rapidly activated upon addition of FBS, but the activation of p38 is delayed compared to that of ERK1/2. In summary, this study showed that ERK1/2 and p38 pathways are essential to mediate initiation of trophoblast differentiation.     

子痫前期患者胎盘组织中visfatin蛋白与mRNA表达及意义

目的:探讨内脂素(visfatin,VF)在子痫前期(PE)患者胎盘组织中的表达及意义。方法:选择2011年8月至2013年12月在温州医科大学附属第一医院住院分娩的孕妇共计100例,根据病情轻重分为重度PE组、轻度PE组和正常妊娠组。采用苏木素-伊红染色法观察3组胎盘组织病理变化;免疫组化法及real-time PCR技术分别检测3组胎盘VF蛋白及mRNA的表达并分析其与子痫前期发病的关系。结果:PE的病理改变主要表现为细胞滋养细胞及合体滋养细胞结构紊乱且形态不完整;细胞滋养细胞增生,合体滋养细胞结节增多;绒毛毛细血管减少、淤血。免疫组化及real-time PCR结果显示胎盘组织中内脂素定位于合体及细胞滋养层细胞的胞浆,随着病情的加重,VF蛋白及mRNA表达量逐渐升高,重度PE组明显高于正常妊娠组,差异有统计学意义(P0.05)。结论:PE患者存在绒毛血管内皮细胞损伤和功能紊乱。胎盘VF蛋白及mRNA在PE孕妇中高表达,表明VF与PE的发生具有一定关系。     

Interleukin-10 receptors are expressed by basement membrane anchored, alpha(6) integrin(+) cytotrophoblast cells in early human placenta.

Cytotrophoblast cells produce interleukin (IL)-10 and express IL-10 receptor mRNA in culture. Furthermore, IL-10 dramatically reduces the synthesis of matrix metalloproteinase (MMP)-9 and the invasivity of cytotrophoblast cells in vitro, suggesting that an autocrine regulatory role in vivo is also possible. To test this hypothesis we investigated the expression of IL-10 receptor protein by first trimester cytotrophoblasts both in vitro and in situ, using flow cytometry and immunohistochemistry. Flow cytometric analyses demonstrated that 75-80% of cytotrophoblasts are able to bind labelled IL-10, suggesting that these cells possess IL-10 receptors in vitro. Serial sections of early human placentae stained for either alpha(5) and alpha(6) integrin subunits, or for IL-10 receptors respectively, revealed that placental cytotrophoblasts possess cell surface IL-10 receptors not only in vitro, but also in vivo. IL-10 receptors were present mainly on alpha(6) integrin expressing villous cytotrophoblast cells and on alpha(6)-positive cells of invasive cell columns located nearest the villous stroma. Differentiated trophoblasts (i.e. alpha(5)-positive cells and villous syncytiotrophoblasts) showed no reactivity. This differential expression of IL-10 receptors suggests that IL-10 might suppress the invasivity of undifferentiated cytotrophoblast cells, in vivo, preserving their non-invasive state in an autocrine manner. The possible involvement in cytotrophoblast proliferation and/or differentiation is also discussed.     

Mucin 15 is expressed in human placenta and suppresses invasion of trophoblast-like cells in vitro

BACKGROUND: Trophoblast invasion is crucial for the development of normal placentas. Mucins are suggested to be involved in cancer invasion. However, the function of mucins in trophoblast invasion has never been reported. This study was to investigate the expression of mucin (MUC) 15 in human placenta and its role in trophoblast invasion. METHODS: MUC15 mRNA in human tissues was analyzed by Northern blot. MUC15 mRNA and protein in human placenta were detected by real-time RT-PCR and Western blot, respectively. The distribution of MUC15 was revealed by immunohistochemistry. The effects of MUC15 on trophoblast invasion in vitro were analyzed by matrigel invasion assay in human choriocarcinoma JAR and JEG-3 cells. RESULTS: MUC15 was expressed most highly in human placenta. MUC15 mRNA and protein increased with gestational age (P < 0.05, first versus third trimester). Immunohistochemistry showed that MUC15 protein was expressed by both cytotrophoblasts and syncytiotrophoblasts, especially at the apical membrane of syncytiotrophoblasts. In addition, MUC15 was found to be present in the glandular epithelium of the decidua. Overexpression of MUC15 substantially decreased matrigel invasion of JAR and JEG-3 cells by 87.5 +/- 1.1 and 83.8 +/- 5.7%, respectively, versus control, which was closely associated with an increase in mRNA expression of tissue inhibitors of metalloproteinases (TIMP)-1 and TIMP-2. Knockdown of MUC15 with small interfering RNA significantly reversed these effects (P < 0.05). CONCLUSIONS: Differential expression of MUC15 in human placentas may play a critical role in the regulation of trophoblast invasion.     

A repertoire of cell cycle regulators whose expression is coordinated with human cytotrophoblast differentiation

Although placental development depends on careful coordination of trophoblast proliferation and differentiation, little is known about the mitotic regulators that are key to synchronizing these events. We immunolocalized a broad range of these regulators in tissue sections of the maternal-fetal interface (first trimester through term) that contained floating villi (which include cytotrophoblasts differentiating into syncytiotrophoblasts) and anchoring villi (which include cytotrophoblasts differentiating into invasive cells). Trophoblast populations at the maternal-fetal interface stained for 16 of the cell cycle regulators whose expression we studied. The staining patterns changed as a function of both differentiation and gestational age. Differentiation along the invasive pathway was associated with entrance into, then permanent withdrawal from, the cell cycle, as evidenced by the orchestrated expression of cyclins, their catalytic subunits, and inhibitors. Surprisingly, we found coexpression of molecules that regulate different portions of the cell cycle in the syncytium. These data, which constitute one of the few examples to date of in situ localization of an extensive repertoire of mitotic regulators, provide the basis for studies aimed at understanding factors that lead to abnormal placentation.     

Changed expression of heat shock proteins in various pathological findings in placentas with intrauterine fetal growth restriction

Heat shock proteins (HSPs) are activated in the cells of most organisms in response to sublethal heat shock and other stressors. It has been reported that HSP27, HSP60, HSP70, and HSP90 are expressed in normal human placenta, and it was thought that these HSPs play a role in the demonstration of cell viability and function. In this study, we performed an immunohistochemical (IHC) study of these HSPs for 27 placentas that had complicated intrauterine fetal growth restriction (IUGR) and compared the IHC findings with the pathological findings. To quantify HSP27, HSP60, HSP70, and HSP90, immunoreacted cells in the chorionic villi, syncytiotrophoblasts (ST), and cytotrophoblasts (CT) were counted. In thrombus, excessive syncytial knots, and avascular villi, the expression of HSPs was higher in the pathological sections compared to control in both ST and CT. In contrast, all HSPs decreased in both ST and CT around the infarction region. The data suggested that chorionic villi cells locally responded to some stresses, e.g., hypoxia and increase or decrease in the expression of HSPs. Although the villous cells around the infarction histologically appear viable, they may have received lethal damage, and as a result the expression of HSPs was decreased. These results are expected to improve our understanding of the pathological findings of IUGR in placentas, including the quality, damage, and function of the chorionic villi.     

Expression and tissue localization of collectin placenta 1 (CL-P1, SRCL) in human tissues

Collectin placenta-1 (CL-P1), also known as scavenger receptor with C-type lectin (SRCL), is a type II membrane glycoprotein that shares structural features with both collectins and type A scavenger receptors. CL-P1 was originally cloned from the placenta and found to be associated with endothelial cells. It binds via its lectin domain to desialyated Lewis X containing glycoproteins and it is able to facilitate internalization of bound ligands. Via positively charged residues in the collagen-like region it binds to negatively charged components of microbial membranes. It has previously been proposed that CL-P1 plays a role in the host defense system and in the clearance of glycoproteins from the blood. With the aims of determining the detailed tissue expression of human CL-P1 we expressed CL-P1 recombinantly in both E. coli and CHO cells, and raised monoclonal antibodies against human CL-P1. Three monoclonal antibodies were characterized and used in immunohistochemical analyses of a panel of cryo- and formalin-fixed sections. We find that CL-P1 mainly associates with cytotrophoblasts and syncytiotrophoblasts of the placenta, alveolar macrophages and to a less degree with macrophage-like and stromal cells of the tonsils. By real-time RT-PCR we verified that the placenta is also the main organ of CL-P1 synthesis. The only source of endothelial cells whereto CL-P1 associates are umbilical cord vein endothelial cells (human umbilical vein endothelial cells, HUVEC). In vitro cultured HUVECs express both the CL-P1 mRNA and show anti-CL-P1 immunoreactivity but CL-P1 locates mainly to the cytosol and not to the membrane of these cells. We conclude that CL-P1 is not a common membrane protein on endothelial cells found in normal tissues under steady state conditions.     

Tissue expression of the S100 protein family-related MRP8 gene in human chorionic villi by in situ hybridization techniques.

The present study examined the tissue-expression of MRP8 in human placenta using a biotinylated DNA-probe for in situ hybridization. During the first and second trimesters high level and synchronous expression of MRP8 was detected in cytotrophoblasts (Langhans' cells), placental-tissue macrophages (Hofbauer cells), fibroblast-like cells, endothelial cells and monocytic lineages in the foetal capillaries. The highest expression was seen in large and oval-shaped cytotrophoblasts and stromal-cell populations at around 8-11 weeks. At term placentas had low level MRP8 expression chiefly in the myelomonocytic lineages in foetal blood vessels. The peripheral monocytes in the maternal space also expressed MRP8 at high levels during the first and second trimesters, which subsequently decreased at term. We suggest three hypotheses based on these results; (1) The initial expression of MRP8 may occur in two cell lineages of extra-embryonic and intra-embryonic origin in the first two trimesters; (2) the cytotrophoblasts, placental-tissue macrophages and fibroblasts may play important roles in the production of placental hormones and the immuno-regulation of foetal acceptance; and (3) MRP8-expression may be synchronously inhibited once the trophoblasts and stromal cell-constituents have differentiated in the chorionic villi.     

解整合素金属蛋白酶19/ADAM19在子痫前期胎盘组织中的表达及其对滋养细胞分泌MMPs的调节

目的通过对子痫前期及正常孕妇胎盘组织中解整合素金属蛋白酶19（ADAM19）的检测及ADAM19对绒毛滋养细胞分泌MMP2,9的调节,探讨ADAM19与子痫前期发病的关系。方法应用免疫组织化学（免疫组化）链霉素抗生物素-过氧化物酶法、免疫印迹技术和RT-PCR技术检测24例正常胎盘组织及46例子痫前期（其中26例为重度子痫前期,20例为轻度子痫前期）胎盘组织中ADAM19蛋白及mRNA的表达;用明胶酶谱方法检测抗ADAM19抗体作用后滋养细胞MMP2,9的分泌变化。结果胎盘组织中,ADAM19主要分布在多种滋养层细胞中,包括细胞滋养层细胞、合体滋养层细胞一和些绒毛间质结缔组织细胞、毛细血管中,其阳性信号不仅定位于细胞膜上,在细胞质中也有分布。正常胎盘中ADAM19的蛋白表达量为0.372±0.016,重度和轻度子痫前期组ADAM19蛋白定量分别为0.766±0.029和0.693±0.041,轻、重度子痫前期组分别与正常组比较,差异均有统计学意义（P〈0.01）,轻度子痫前期与重度子痫前期比较,差异无统计学意义（P〉0.05）。ADAM19mRNA在正常组胎盘中的量为0.205±0.084,在重度和轻度子痫前期组中分别为0.481±0.057和0.454±0.033,轻、重度子痫前期组分别与正常组比较,差异均有统计学意义（P〈0.01）,轻度子痫前期与重度子痫前期比较,差异无统计学意义（P〉0.05）。在体外培养的滋养层细胞中,100μg/L浓度的抗ADAM19抗体在作用12h即可以抑制滋养细胞MMP2,MMP9的分泌,其作用呈浓度依赖。结论子痫前期胎盘组织中ADAM19过表达可能与子痫前期的发生和发展有关;在子痫前期的发生中,ADAM19可能是在妊娠早期抑制滋养细胞的浸润而导致胎盘浅着床的。     

Maternal antibodies enhance or prevent cytomegalovirus infection in the placenta by neonatal Fc receptor-mediated transcytosis

How human cytomegalovirus (CMV) reaches the fetus across the placenta is unknown. The major viral cause of congenital disease, CMV infects the uterine-placental interface with varied outcomes depending on the strength of maternal humoral immunity and gestational age. Covering the surface of villi that float in blood, syncytiotrophoblasts express the neonatal Fc receptor (FcRn) that transports IgG for passive immunity. Immunohistochemical analysis of early-gestation biopsy specimens showed an unusual pattern of CMV replication proteins in underlying villus cytotrophoblasts, whereas syncytiotrophoblasts were spared. Found in placentas with low to moderate CMV-neutralizing antibody titers, this pattern suggested virion transcytosis across the surface. In contrast, syncytiotrophoblasts from placentas with high neutralizing titers contained viral DNA and caveolin-1-positive vesicles in which IgG and CMV glycoprotein B co-localized. In villus explants, IgG-virion transcytosis and macrophage uptake were blocked with trypsin-treatment and soluble protein A. Quantitative analysis in polarized epithelial cells showed that FcRn-mediated transcytosis was blocked by the Fc fragment of IgG, but not F(ab')(2). Our results suggest that CMV virions could disseminate to the placenta by co-opting the receptor-mediated transport pathway for IgG. These findings could explain the efficacy of hyperimmune IgG for treatment of primary CMV infection during gestation and support vaccination.     

Promyelocytic leukaemia (PML) protein expression in human placenta and choriocarcinoma

Promyelocytic leukaemia (PML) protein, the product of the pml gene, is heterogeneously expressed in various normal and neoplastic tissues, and the fusion of the pml gene with retinoic acid receptor-alpha is believed to be a central mechanism in acute PML tumourigenesis. As PML is important for controlling major cellular processes, such as growth and differentiation, it is believed that it plays an important role during human gestation. The human placenta is a critical organ for the maintenance of gestation, but the expression pattern and functional significance of PML in the placenta have not been documented. The present study has therefore investigated the expression of PML in the human placenta and in choriocarcinoma, and has observed the biological effects following the overexpression of PML in choriocarcinoma cell lines (BeWo and JEG-3). In the human placenta, PML expression was readily found in villous stromal fibroblasts, capillary endothelial cells, Hofbauer cells, and occasionally in amnion cells. Moreover, immunoblotting of placental lysates demonstrated increased PML expression with increasing gestation. Interestingly, PML expression was confined to intermediate trophoblasts and syncytiotrophoblastic giant cells at the placental site (placental site giant cells) in the trophoblastic cell population. Intermediate trophoblasts at non-placental sites, and villous cytotrophoblasts and syncytiotrophoblasts consistently did not express PML. Further screening of PML expression in hydatidiform moles (n = 4) and choriocarcinomas (n = 7) also revealed selective PML expression in intermediate trophoblastic cells and syncytiotrophoblastic cells, but not in the cytotrophoblastic populations, which corresponds well with observations in the placental bed. Adenoviral transduction of PML resulted in a marked reduction in cell growth in both choriocarcinoma cell lines, which was associated with increased apoptosis. The findings of the present study strongly suggest that PML plays an important role in human placental development and growth, and in the pathobiology of trophoblasts and trophoblastic neoplasia.     

人早期胎盘绒毛运动神经诱向因子1及其受体的免疫组织化学定位

为了解人胎盘绒毛是不存在运动神经诱向因子及其可能的功能意义，本实验用ＭＮＴＦ１单克隆抗体及抗独特型单克隆抗体在人早期胎盘绒毛石蜡切片上进行免疫组织化学反应，对人早期胎盘绒毛的ＭＮＴＦ１及其受体进行定位。结果显示，胎盘绒毛的细胞滋养层细胞，合体滋养层细胞和基质细胞均呈ＭＮＴＦ１强免疫反尖，ＭＮＴＦ１样免疫反应物质分布在胞质内，胞核内阴性。