HTR-8/SVneo Cells

HTR-8/SVneo is a human trophoblast cell line derived from the chorionic villi of a first-trimester placenta, specifically from a 6-to-12-week-old embryo. These cells were immortalized by transfecting them with the gene encoding the simian virus 40 (SV40) large T antigen, which extends their lifespan while maintaining characteristics typical of extravillous invasive trophoblasts. This cell line expresses several key markers associated with extravillous trophoblasts, including insulin-like growth factor II (IGF-II), NDOG-5, proliferating cell nuclear antigen (PCNA), and a range of integrins (α1, α3, α5, αv, and β1 subunits, along with the αvβ3/β5 vitronectin receptor). It is negative for macrophage marker 63/D3, endothelial cell marker factor VIII, and α6 and β4 integrin subunits, confirming its trophoblast lineage and distinguishing it from other cell types such as macrophages and endothelial cells.

HTR-8/SVneo cells are widely used as a model to study trophoblast invasion and placental biology, particularly the epithelial-to-mesenchymal transition (EMT), which is crucial for trophoblasts’ invasive behavior during placental development. Research has shown that these cells exhibit a mixed population of epithelial and mesenchymal phenotypes, with the ability to undergo EMT under standard culture conditions. This transition is mediated by TGF-β signaling, which promotes the mesenchymal phenotype, as evidenced by the upregulation of mesenchymal markers such as vimentin and the downregulation of epithelial markers like E-cadherin. This makes HTR-8/SVneo a valuable in vitro model for studying the molecular mechanisms underlying EMT in trophoblasts and its implications in both normal placental development and pregnancy-related disorders.

Studies have further demonstrated that HTR-8/SVneo cells can form spheroids, which predominantly express epithelial markers. When these spheroids are re-plated in 2D culture, the cells exhibit a shift towards a mesenchymal phenotype, indicating an ongoing EMT process. This cell line’s unique properties, including its responsiveness to TGF-β and its mixed epithelial-mesenchymal nature, provide critical insights into the complex cellular dynamics of trophoblast invasion and the regulation of placental development, offering a robust platform for investigating pregnancy-related pathologies such as pre-eclampsia and intrauterine growth restriction.