The Role of E-cadherin in the Motility and Invasion of Implantation Site Intermediate Trophoblast.

During early pregnancy, intermediate (extravillous) trophoblast infiltrates the basal plate and invades the spiral arteries, a physiological process required to establish the maternal-fetal circulation. Immunostaining studies have shown that differentiation of trophoblast into this invasive subpopulation is associated with down-regulation of E-cadherin expression. To study the function of E-cadherin in trophoblast in vitro, we restored E-cadherin expression in an E-cadherin negative human implantation site intermediate trophoblastic cell line, IST-1, using a recombinant adenovirus, E-cad/Ad5 which constitutively expresses E-cadherin. In contrast to the control IST-1 cells which were individual and pleomorphic in shape, E-cad/Ad5 transduced cells were cohesive, uniform, and round. The motility and invasiveness of E-cad/Ad5 transduced IST-1 cells, as compared with the control cells, was significantly reduced. These effects were contact-dependent and were attenuated by a function-perturbing anti-E-cadherin antibody. In conclusion, our results indicate that expression of E-cadherin in IST-1 cells results in a contact-mediated inhibition of motility and invasion and suggest an important role for E-cadherin down-regulation in the intermediate trophoblast during implantation.

Primary and secondary drug screening assays for Friedreich ataxia.

Friedreich ataxia (FRDA) is an autosomal recessive neuro- and cardiodegenerative disorder for which there are no proven effective treatments. FRDA is caused by decreased expression and/or function of the protein frataxin. Frataxin chaperones iron in the mitochondrial matrix for the assembly of iron-sulfur clusters (ISCs), which are prosthetic groups critical for the function of the Krebs cycle and the mitochondrial electron transport chain (ETC). Decreased expression of frataxin or the yeast frataxin orthologue, Yfh1p, is associated with decreased ISC assembly, mitochondrial iron accumulation, and increased oxidative stress, all of which contribute to mitochondrial dysfunction. Using yeast depleted of Yfh1p, a high-throughput screening (HTS) assay was developed in which mitochondrial function was monitored by reduction of the tetrazolium dye WST-1 in a growth medium with a respiration-only carbon source. Of 101 200 compounds screened, 302 were identified that effectively rescue mitochondrial function. To confirm activities in mammalian cells and begin understanding mechanisms of action, secondary screening assays were developed using murine C2C12 cells and yeast mutants lacking specific complexes of the ETC, respectively. The compounds identified in this study have potential relevance for other neurodegenerative disorders associated with mitochondrial dysfunction, such as Parkinson disease.

Molecular genetic analysis of placental site trophoblastic tumors and epithelioid trophoblastic tumors confirms their trophoblastic origin.

Trophoblastic tumors represent a unique group of human neoplasms because they are derived from fetal tissue. Except for choriocarcinoma, the neoplasms that develop from human trophoblast are poorly characterized. Placental site trophoblastic tumors and epithelioid trophoblastic tumors are thought to arise from intermediate (extravillous) trophoblasts based on histopathological studies, but direct molecular evidence of a trophoblastic origin has not been established. In this study, we performed molecular analysis in an attempt to confirm their presumable trophoblastic origin. We demonstrated that such tumors contain a Y-chromosomal locus and/or new (paternal) alleles not present in adjacent normal uterine tissue in all 31 informative cases. Loss of heterozygosity was found in 60% of tumors and all 42 tumors assessed contained wild-type K-ras. All of the trophoblastic tumors were heterozygous in at least 1 of 10 single-nucleotide polymorphism markers studied in contrast to homozygosity in all 10 single-nucleotide polymorphism markers in most complete hydatidiform moles indicating that these tumors are not related to complete hydatidiform moles. This study provides the first molecular evidence that placental site trophoblastic tumors and epithelioid trophoblastic tumors are of fetal (trophoblastic) origin.