Endocrine Abstracts

Improved therapies for pancreatic and pituitary neuroendocrine tumors (NETs), which may occur in Multiple Endocrine Neoplasia type 1 (MEN1), are needed. We assessed the effects of pasireotide, a somatostatin analogue with high affinity for somatostatin receptors (SSTRs) −1, −2, −3 and −5, in a mouse model of MEN1. Men1+/− mice treated from 12 months of age with 40 μg/g pasireotide (n=71), or phosphate-buffered sal...

Multiple Endocrine Neoplasia type 1 (MEN1) is an autosomal dominant disorder characterised by the combined occurrence of parathyroid, pituitary and pancreatic islet tumours, and is due to mutations of the MEN1 gene, which encodes the tumour suppressor protein menin. MicroRNAs (miRNA) are non-coding single stranded RNAs that post-transcriptionally regulate gene expression. Alterations in miRNA expression, including downregulation of two miRNAs, miR-15a and miR-16-1, have been r...

Adaptor protein-2 (AP2) is a heterotetramer of α, β, μ, and σ subunits that is pivotal in clathrin-mediated endocytosis and facilitates internalisation of plasma membrane constituents such as the calcium-sensing receptor (CaSR). AP2 σ subunit (AP2σ) missense mutations (Arg15Cys, Arg15His and Arg15Leu) result in familial hypocalciuric hypercalcaemia type 3 (FHH3) and decrease the sensitivity of CaSR-expressing cells to changes in extracellular calc...

The calcium-sensing receptor (CaSR) is a guanine-nucleotide-binding protein (G-protein)-coupled receptor that has a central role in calcium homeostasis. Loss-of-function mutations of the CaSR result in familial hypocalciuric hypercalcemia type 1 (FHH1) and loss-of-function coding mutations in the CaSR-associated G-protein subunit Gα11 have been reported to cause FHH2 in only two patients to date. The aim of our study was therefore to characterise additional <em...

Autosomal dominant hypocalcaemia (ADH) is a disorder that needs to be distinguished from hypoparathyroidism, as ADH patients are at risk of nephrocalcinosis and renal failure when treated with activated vitamin D preparations. ADH types 1 and 2 are due to gain-of-function mutations of the calcium-sensing receptor (CaSR) and G-protein α 11 (Gα11), respectively. CaSR targeted drugs, known as calcilytics, rectify the gain-of-function associated with ADH1-causing mutatio...

We have studied clinical and pre-clinical models to investigate neuroendocrine tumour (NET) development and efficacy of novel therapy for NETs. We focused on multiple endocrine neoplasia type 1 (MEN1), an autosomal dominantly inherited condition characterised by the combined occurrence of pancreatic islet and anterior pituitary NETs with parathyroid and adrenocortical tumours. MEN1 is due to MEN1 gene mutations that inactivate Menin, a tumour suppressor. Our clinical studies r...

The calcium-sensing receptor (CaSR) is a guanine-nucleotide-binding protein (G-protein)-coupled receptor that has a central role in calcium homeostasis. Loss-of-function mutations of the CaSR result in familial hypocalciuric hypercalcemia type 1 (FHH1) and gain-of-function mutations in autosomal dominant hypocalcemia (ADH). Recently, loss-of-function Gα11 mutations have been identified to cause FHH2 and we hypothesised that gain-of-function Gα11...

Dent’s disease is a renal proximal tubular Fanconi disorder characterised by generalised loss of solutes incuding insulin, glucose, PTH, amino acids and vitamin-D binding protein and is associated with rickets in 25% and phosphaturia in ~40% of patients. Dent’s disease is caused by mutations in the chloride/proton antiporter CLC-5, which, with megalin and cubilin has a role in receptor-mediated endocytosis and vesicle trafficking. To further elucidate the role of CLC...

The hypoparathyroidism-deafness-renal dysplasia (HDR) syndrome is an autosomal dominant disorder caused by germline mutations of the dual zinc-finger (ZnF) transcription factor, GATA3. To date, 51 GATA3 mutations have been reported, which can be divided broadly into three structural-functional classes: i) mutations that lead to a loss of DNA binding and involve ZnF2; ii) mutations, usually of ZnF1, that bind DNA but result in reduced DNA binding affinity; and iii) mut...

The calcium-sensing receptor (CaSR) is a G-protein coupled receptor that regulates extracellular calcium concentration. The CaSR is also implicated in the pathogenesis of non-calcium disorders such as vascular calcification and diabetes, which are leading causes of cardiovascular disease. Common CaSR single nucleotide polymorphisms (SNPs) have been demonstrated to be determinants of calcium metabolism. The aim of this study was to investigate whether CaSR SNPs may influence va...