Endocrine Abstracts

In vitro human thyroid follicular cells have been shown to secrete vascular endothelial growth factors (VEGFs). VEGFs transduce their effects by binding to their receptors, VEGFRs, leading to receptor phosphorylation and recruitment of downstream signalling molecules. Using RT-PCR we found that normal human thyroid follicular cells in culture express VEGFR-1, VEGFR-2 and VEGFR-3. Western blotting using antisera specific for phosphotyrosine at 1214 of the GRB2 SH2 bindin...

The plasminogen activator (PA) system plays a central role in biological processes that involve extracellular proteolysis including tissue remodelling, blood clotting, angiogenesis and metastases. The thyroid gland is highly vascular and undergoes extensive remodelling in goitre. We found that primary cultures of human thyroid follicular cells secrete large amounts of PAs (2.5-110 U per ml per day per 105 cells), both urokinase-like (uPA) and tissue-type (tPA), and ...

VEGF exerts its effects by binding to two tyrosine kinase receptors, KDR and VEGFR1. KDR is critical for transmitting signals for proliferation and migration of endothelial cells but is also expressed in several non-endothelial cells, and is elevated in some human tumour cells. We investigated KDR expression in human thyroid epithelial cells in vitro and thyroid cancers compared with normal thyroid samples examined ex vivo. Expression of KDR was demonstrated usin...

The sodium iodide symporter (NIS) mediates the uptake of iodide into thyroid follicular cells. The pituitary tumor transforming gene (PTTG) is a multifunctional oncogene which stimulates expression of fibroblast growth factor-2 (FGF-2) via the PTTG binding factor (PBF). PTTG, FGF-2 and PBF are all up-regulated in thyroid cancer. PTTG and FGF-2 inhibit NIS mRNA expression and iodide uptake in rat thyroid FRTL5 cells. We have shown previously that both PTTG and PBF repres...