Endocrine Abstracts

Whilst the majority of familial medullary thyroid cancer (MTC) is caused by germline mutations of the RET proto-oncogene, there are families and individuals with predisposition to MTC in whom no RET mutation has been identified (non-RET MTC). Recently, we identified novel mutations in a single gene termed MTC2 in non-RET MTC individuals by whole exome sequencing. The precise role of these MTC2 germline mutations in MTC tumorigenesis is however unclear. Here, we examined the fu...

Although the sodium iodide symporter (NIS) is expressed in 70–80% of breast cancers, only 20–30% is located at the plasma membrane (PM) and therefore functional. Previous work in thyroid cells leads demonstrated that PBF redistributes NIS from the PM into intracellular vesicles, potently reducing radioiodide uptake. We therefore examined whether increased membranous NIS could facilitate radioiodide therapy for breast cancer. Immunofluorescent microscopy revealed co-l...

Pituitary tumor-transforming gene binding factor (PBF) is a ubiquitous glycoprotein which is over-expressed in thyroid, breast and other endocrine cancers, and modulates cellular invasion, radioiodine uptake and thyroid hormone efflux. Papillary thyroid cancer patients with high PBF expression show decreased disease-specific survival compared to those with lower expression. PBF expression has recently been correlated with breast cancer metastasis and colon cancer extra-mural v...

PBF is a ubiquitous glycoprotein which is over-expressed particularly in endocrine and endocrine-related cancers. Previously classified as a proto-oncogene, 11 substitution-missense mutations of PBF have now been reported in tumours from patients with ovarian, prostate and colorectal cancers via the COSMIC database, suggesting PBF may in fact be an oncogene. We have therefore examined the biological implications of all 11 mutations. Substitution mutations, which occurred acros...

Whilst, radioiodine ablation is an effective therapy for many patients with thyroid cancer, a subset of patients are incapable of accumulating sufficient iodide-131 for effective treatment, due to low sodium–iodide symporter (NIS) activity. Previous work has identified that the overexpression of pituitary tumor transforming gene (PTTG) binding factor (PBF) in thyroid cells leads to the redistribution of NIS from the plasma membrane into intracellular vesicles, thereby red...

Thyroid growth and differentiation are regulated by TSH via its receptor (TSHR), whilst growth factors signal in parallel via the MAPK/ERK and PI3K/AKT pathways. Aberrant thyroid growth is largely driven by molecular alterations within these signalling pathways. The proto-oncogene pituitary tumor-transforming gene-binding factor (PBF) is expressed in normal thyroid and upregulated in human goitre and thyroid cancer. High PBF expression is associated with tumour recurrence, dis...

The clinical effectiveness of ablative radioiodine treatment is limited by the ability of the sodium iodide symporter (NIS) to uptake 131I. A significant proportion of well-differentiated thyroid tumours are unable to concentrate sufficient radioiodine for effective therapy, and in other tumour models such as breast, where radioiodine uptake would be an attractive therapeutic option, uptake is insufficient. Pituitary tumor-transforming gene-binding factor (PBF/ PTTG...

The pituitary tumor-transforming gene-binding factor (PBF) is a relatively uncharacterised proto-oncogene, which is overexpressed in thyroid tumours. PBF elicits tumor growth in nude mice, whilst thyroid targeted transgenic overexpression in the PBF-Tg mouse induces hyperplasia and macrofollicular lesions, accompanied by induction of the E2 ubiquitin ligase Rad6. Our previous unpublished data showed that PBF binds to p53, and reduces stimulation of downstream target genes by c...

Pituitary tumor transforming gene (PTTG) binding factor (PBF) is a proto-oncogene which is frequently upregulated in endocrine cancers. PBF has previously been determined to contain several putative signal sequences within its 180 amino acids. Previous studies have shown the nuclear localisation signal (NLS) to be functional and prediction software now suggests the presence of a putative leucine-rich nuclear export signal (NES) between residues 17 and 27. PBF is known to shutt...

p53 is rarely mutated in thyroid papillary carcinomas, despite the thyroid being highly sensitive to ionising radiation. The pituitary tumor transforming gene binding factor (PBF) is a proto-oncogene overexpressed in thyroid cancer. Oncogenic levels of PBF result in cell transformation in vitro and tumourigenesis in vivo. By serendipity we have found that PBF interacts directly with the tumour suppressor protein p53. In light of these data we have investigated th...