Effects of EpCAM overexpression on human breast cancer cell lines

<p>Abstract</p> <p>Background</p> <p>Recently, EpCAM has attracted major interest as a target for antibody- and vaccine-based cancer immunotherapies. In breast cancer, the EpCAM antigen is overexpressed in 30-40% of all cases and this increased expression correlates with poor prognosis. The use of EpCAM-specific monoclonal antibodies is a promising treatment approach in these patients.</p> <p>Methods</p> <p>In order to explore molecular changes following EpCAM overexpression, we investigated changes of the transcriptome upon EpCAM gene expression in commercially available human breast cancer cells lines Hs578T and MDA-MB-231. To assess cell proliferation, a tetrazolium salt based assay was performed. A TCF/LEF Reporter Kit was used to measure the transcriptional activity of the Wnt/β-catenin pathway. To evaluate the accumulation of β-catenin in the nucleus, a subcellular fractionation assay was performed.</p> <p>Results</p> <p>For the first time we could show that expression profiling data of EpCAM transfected cell lines Hs578T^EpCAMand MDA-MB-231^EpCAMindicate an association of EpCAM overexpression with the downregulation of the Wnt signaling inhibitors SFRP1 and TCF7L2. Confirmation of increased Wnt signaling was provided by a TCF/LEF reporter kit and by the finding of the nuclear accumulation of ß-catenin for MDA-MB-231^EpCAMbut not Hs578T^EpCAMcells. In Hs578T cells, an increase of proliferation and chemosensitivity to Docetaxel was associated with EpCAM overexpression.</p> <p>Conclusions</p> <p>These data show a cell type dependent modification of Wnt signaling components after EpCAM overexpression in breast cancer cell lines, which results in marginal functional changes. Further investigations on the interaction of EpCAM with SFRP1 and TCF7L2 and on additional factors, which may be causal for changes upon EpCAM overexpression, will help to characterize unique molecular properties of EpCAM-positive breast cancer cells.</p

Cellular and complement-dependent cytotoxicity of Ep-CAM-specific monoclonal antibody MT201 against breast cancer cell lines

MT201 is a fully human monoclonal IgG1 antibody with moderate affinity for epithelial cell adhesion molecule (Ep-CAM) being clinically developed for the treatment of carcinomas. Like many other clinically validated IgG1 monoclonal antibodies, MT201 primarily acts by antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Here, we analysed ADCC and CDC induced by MT201 and, as reference, trastuzumab against a panel of nine human breast cancer cell lines expressing distinct surface levels of Ep-CAM and human epithelial growth factor receptor type 2 antigen. Maximal cell lysis by ADCC by MT201 and trastuzumab in the presence of peripheral mononuclear cells did not significantly differ when averaged over the nine cell lines, but showed marked differences with respect to individual cell lines. The extent of cell lysis at intermediate surface target density was highly variable, suggesting a dominant influence of other susceptibility factors. Only one breast cancer cell line was eliminated via CDC, but only by MT201. Resistance to CDC appeared to correlate with high expression levels of complement resistance factors. Our present data as well as recent data on the prevalence and prognostic relevance of Ep-CAM expression in metastatic breast cancer suggest that Ep-CAM-specific monoclonal IgG1 antibodies may have a significant therapeutic potential in the treatment of breast cancer

Ecological divergence and calcaneal-cuboid morphology in gorillas

Objectives: Gorillas are diverse behaviorally and ecologically with higher frequencies of arboreality and frugivory observed in populations living at lower altitudes compared to those living at higher altitudes. Previous studies have shown that the more arboreal western lowland gorilla has hallucial tarsometatarsal and talocrural joint morphologies associated with enhanced hallucial abduction and foot inversion capabilities whereas the more terrestrial eastern gorilla does not. Here we examine how known ecological and behavioral differences among gorillas relate to variation in calcaneal and cuboid morphology. Specifically, we test whether gorillas that climb more frequently (i.e., western lowland and lowland grauer gorillas) have cuboid-metatarsal and calcaneocuboid morphologies that facilitate increased foot mobility compared to those that climb less often (i.e., mountain and highland grauer gorillas). Methods: We quantify the relative areas of articular and nonarticular surfaces, angles between articular surfaces, articular surface curvatures, the relative length and depth of the calcaneocuboid joint, and the relative size of the calcaneal tuber using three-dimensional models of gorilla calcanei and cuboids (n = 90 and 81, respectively). Results: Our results, based on univariate and multivariate analyses, show that western and eastern gorillas follow our predicted arboreal-terrestrial morphocline in terms of their calcaneal and cuboid morphology; however, highland and lowland grauer gorilla populations do not. Conclusions: This study has implications for understanding gorilla foot function and the evolutionary processes responsible for producing the morphological patterns among living gorilla populations. Future studies of gorilla morphological diversity may provide a useful comparative model for studies of locomotor evolution in extinct clades

A pesca e o conhecimento ecológico local dos pescadores de acará-disco (Symphysodon aequifasciatus, Pellegrin 1904: Cichlidae) na Reserva de Desenvolvimento Sustentável Piagaçu-Purus, baixo rio Purus, Brasil

O acará-disco (Symphysodon aequifasciatus, Pellegrin 1904), peixe endêmico da bacia amazônica, é uma das espécies ornamentais mais conhecidas do mundo. Apesar disso, informações sobre a explotação desse animal em vida livre são quase inexistentes na literatura científica. Nesse artigo, a pesca de pequena escala do acará-disco na Reserva de Desenvolvimento Sustentável Piagaçu-Purus (RDS-PP), baixo rio Purus, Amazonas, é caracterizada com base em entrevistas estruturadas e abertas com pescadores e habitantes, bem como em observações de campo. A pesca do acará-disco é sazonal, ocorrendo durante o período de seca. É realizada por pescadores locais, utilizando atratores de pesca e uma técnica de detecção e estimativa de abundância por mergulho em apneia. O armazenamento local é feito em tanques de madeira e os peixes são transportados em recipientes plásticos para distribuição nos mercados regionais por meio de barcos dos próprios pescadores, barcos de linha ou jangadas. Os peixes são vendidos para empresas exportadoras especializadas de Manaus. Neste estudo, descrevemos o conhecimento ecológico local dos pescadores de acará-disco na RDS-PP e discutimos sua importância para a gestão da pesca nessa unidade de conservação