Effect of Menin Deletion in Early Osteoblast Lineage on the Mineralization of an In Vitro 3D Osteoid-like Dense Collagen Gel Matrix.

Bone has a complex microenvironment formed by an extracellular matrix (ECM) composed mainly of mineralized type I collagen fibres. Bone ECM regulates signaling pathways important in the differentiation of osteoblast-lineage cells, necessary for bone mineralization and in preserving tissue architecture. Compared to conventional 2D cell cultures, 3D in vitro models may better mimic bone ECM and provide an environment to support osteoblastic differentiation.

Genetic Deletion of Menin in Mouse Mesenchymal Stem Cells: An Experimental and Computational Analysis.

Loss-of-function mutations in the tumor-suppressor gene cause the multiple endocrine neoplasia type 1 syndrome. Menin, the gene product, is expressed in many tissues, including bone, where its function remains elusive. We conditionally inactivated menin in mesenchymal stem cells (MSCs) using paired-related homeobox 1 (Prx1)-Cre and compared resultant skeletal phenotypes of ; menin-knockout mice (KO) and wild-type controls using in vivo and in vitro experimental approaches and mechanics simulation.

Novel Glial Cells Missing-2 (GCM2) variants in parathyroid disorders.

Objective: The aim of this study was to analyze variants of the gene glial cells missing-2 (GCM2), encoding a parathyroid cell-specific transcription factor, in familial hypoparathyroidism and in familial isolated hyperparathyroidism (FIHP) without and with parathyroid carcinoma.

Design: We characterized 2 families with hypoparathyroidism and 19 with FIHP in which we examined the mechanism of action of GCM2 variants.

Methods: Leukocyte DNA of hypoparathyroid individuals was Sanger sequenced for CASR, PTH, GNA11 and GCM2 mutations.

The three common polymorphisms p.A986S, p.R990G and p.Q1011E in the calcium sensing receptor (CASR) are not associated with chronic pancreatitis.

Background: The calcium sensing receptor (CASR) is a G protein-coupled receptor that is responsible for assessing extracellular Ca levels and thus plays a crucial role in calcium homeostasis. Hypercalcemia is a metabolic risk factor for pancreatitis and rare CASR variants have been described in patients with chronic pancreatitis. At the carboxy-terminal tail of CASR, there is a cluster of three common polymorphisms, p.

Homozygous Calcium-Sensing Receptor Polymorphism R544Q Presents as Hypocalcemic Hypoparathyroidism.

Context: Autosomal dominant hypocalcemia type 1 (ADH1) is caused by heterozygous activating mutations in the calcium-sensing receptor gene (CASR). Whether polymorphisms that are benign in the heterozygous state pathologically alter receptor function in the homozygous state is unknown.

Objective: To identify the genetic defect in an adolescent female with a history of surgery for bilateral cataracts and seizures.

Transforming Growth Factor-beta Regulation of Ephrin Type-A Receptor 4 Signaling in Breast Cancer Cellular Migration.

Breast cancer consists of a range of tumor subtypes with different clinical characteristics, disease prognosis, and treatment-response. Luminal breast cancer has the best prognosis while basal-like breast cancer (BLBC) represents the worst subtype. Transforming growth factor-beta (TGFβ) plays a prominent role in stimulating the migration and invasion of malignant breast cancer cells contributing to tumor progression.

Calcium-Sensing Receptor Gene: Regulation of Expression.

The human calcium-sensing receptor gene (CASR) has 8 exons, and localizes to chromosome 3q. Exons 1A and 1B encode alternative 5'-untranslated regions (UTRs) that splice to exon 2 encoding the AUG initiation codon. Exons 2-7 encode the CaSR protein of 1078 amino acids.

Calcium-sensing receptor, proinflammatory cytokines and calcium homeostasis.

The calcium-sensing receptor (CaSR) expressed in the parathyroid gland and the kidney tubule acts as the calciostat and orchestrates blood calcium homeostasis by modulating production and release of parathyroid hormone (PTH) and active vitamin D that influence Ca(2+) fluxes across the bone, kidney and intestine. Here we consider the role of the CaSR as a responder to proinflammatory cytokines released as part of the innate immune response to tissue injury and inflammation with resetting of the calciostat on the one hand and as a promoter and mediator of the initial inflammatory response on the other. The importance of the CaSR in systemic calcium homeostasis is exemplified by the fact that inactivating and activating mutations in the gene result in hypercalcemia and hypocalcemia, respectively.

The Retinoblastoma Tumor Suppressor Protein (pRb)/E2 Promoter Binding Factor 1 (E2F1) Pathway as a Novel Mediator of TGFβ-induced Autophagy.

TGFβ is a multifunctional cytokine that regulates cell proliferation, cell immortalization, and cell death, acting as a key homeostatic mediator in various cell types and tissues. Autophagy is a programmed mechanism that plays a pivotal role in controlling cell fate and, consequently, many physiological and pathological processes, including carcinogenesis. Although autophagy is often considered a pro-survival mechanism that renders cells viable in stressful conditions and thus might promote tumor growth, emerging evidence suggests that autophagy is also a tumor suppressor pathway.

Cinacalcet Treatment in an Adolescent With Concurrent 22q11.2 Deletion Syndrome and Familial Hypocalciuric Hypercalcemia Type 3 Caused by AP2S1 Mutation.

Context: The 22q11.2 deletion syndrome (DS) is a common multiple anomaly syndrome in which typical features include congenital heart defects, facial dysmorphism, and palatal anomalies. Hypocalcemia due to hypoparathyroidism is a common endocrine manifestation resulting from variable parathyroid hypoplasia, but hypercalcemia has not previously been reported in 22q11.

The leukemia inhibitory factor (LIF) and p21 mediate the TGFβ tumor suppressive effects in human cutaneous melanoma.

Background: Cutaneous melanoma is the most lethal skin cancer and its incidence in developed countries has dramatically increased over the past decades. Localized tumors are easily treated by surgery, but advanced melanomas lack efficient treatment and are associated with very poor outcomes. Thus, understanding the processes underlying melanoma development and progression is critical.

Osteoblast menin regulates bone mass in vivo.

Menin, the product of the multiple endocrine neoplasia type 1 (Men1) tumor suppressor gene, mediates the cell proliferation and differentiation actions of transforming growth factor-β (TGF-β) ligand family members. In vitro, menin modulates osteoblastogenesis and osteoblast differentiation promoted and sustained by bone morphogenetic protein-2 (BMP-2) and TGF-β, respectively. To examine the in vivo function of menin in bone, we conditionally inactivated Men1 in mature osteoblasts by crossing osteocalcin (OC)-Cre mice with floxed Men1 (Men1(f/f)) mice to generate mice lacking menin in differentiating osteoblasts (OC-Cre;Men1(f/f) mice).

Breast cancer anti-estrogen resistance 3 inhibits transforming growth factor β/Smad signaling and associates with favorable breast cancer disease outcomes.

Introduction: This study helps to define the implications of breast cancer anti-estrogen resistance 3 (BCAR3) in breast cancer and extends the current understanding of its molecular mechanism of action. BCAR3 has been shown to promote cell proliferation, migration and attachment to extracellular matrix components. However, in a cohort of metastatic breast cancer patients who received tamoxifen treatment, high BCAR3 mRNA levels were associated with favorable progression-free survival outcome.

Increased prevalence of the GCM2 polymorphism, Y282D, in primary hyperparathyroidism: analysis of three Italian cohorts.

Context: Glial cells missing-2 (GCM2) is key for parathyroid gland organogenesis. Its persistent expression in the adult parathyroid raises the possibility that overactive forms play a role in the evolution of parathyroid hyperactivity or tumorigenesis. A GCM2 c.

Novel homozygous inactivating mutation of the calcium-sensing receptor gene (CASR) in neonatal severe hyperparathyroidism-lack of effect of cinacalcet.

Background: NSHPT is a life-threatening disorder caused by homozygous inactivating calcium-sensing receptor (CASR) mutations. In some cases, the CaSR allosteric activator, cinacalcet, may reduce serum PTH and calcium levels, but surgery is the treatment of choice.

Objective: To describe a case of NSHPT unresponsive to cinacalcet.

Codon Arg15 mutations of the AP2S1 gene: common occurrence in familial hypocalciuric hypercalcemia cases negative for calcium-sensing receptor (CASR) mutations.

Context: Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant disorder with three known subtypes: FHH1, FHH2, and FHH3. About 65% of FHH cases are FHH1, caused by inactivating mutations of the calcium-sensing receptor (CASR) gene. FHH3 was recently found to be caused by codon Arg15 (p.

Involvement of the osteoinductive factors, Tmem119 and BMP-2, and the ER stress response PERK-eIF2α-ATF4 pathway in the commitment of myoblastic into osteoblastic cells.

The osteoinductive factors BMP-2 and Tmem119 that promote the differentiation of myoblasts into osteoblasts, each increase the levels of the other. However, the relative contributions of BMP-2 and Tmem119 to the osteogenic differentiation and the mechanisms involved are incompletely understood. In the present study, we examined the relationship among BMP-2, Tmem119, and the PERK-eIF2α-ATF4 endoplasmic reticulum (ER) stress response pathway in the differentiation of C2C12 myoblasts into osteoblastic cells.

Identification and functional characterization of three NoLS (nucleolar localisation signals) mutations of the CDC73 gene.

Hyperparathyroidism Jaw-Tumour Syndrome (HPT-JT) is characterized by primary hyperparathyroidism (PHPT), maxillary/mandible ossifying fibromas and by parathyroid carcinoma in 15% of cases. Inactivating mutations of the tumour suppressor CDC73/HRPT2 gene have been found in HPT-JT patients and also as genetic determinants of sporadic parathyroid carcinoma/atypical adenomas and, rarely, typical adenomas, in familial PHPT. Here we report the genetic and molecular analysis of the CDC73/HRPT2 gene in three patients affected by PHPT due to atypical and typical parathyroid adenomas, in one case belonging to familial PHPT.

The CASR gene: alternative splicing and transcriptional control, and calcium-sensing receptor (CaSR) protein: structure and ligand binding sites.

The calcium-sensing receptor (CaSR) is a G protein-coupled receptor encoded by a single copy gene. The human CASR gene spans ~103-kb and has eight exons. Promoters P1 and P2 drive transcription of exons 1A and 1B, respectively, encoding alternative 5'-UTRs that splice to exon 2 encoding the common part of the 5'-UTR.

CDC73 mutations and parafibromin immunohistochemistry in parathyroid tumors: clinical correlations in a single-centre patient cohort.

Objective: To determine if molecular and immunohistochemical (IHC) features of the HRPT2/CDC73 gene and its product, parafibromin, predict the natural history of parathyroid malignancy, particularly atypical adenoma, as seen in a single-centre patient cohort.

Methods: Matched tumor and non-tumor tissues were obtained from 46 patients with parathyroid carcinoma (CA) (n = 15), atypical adenoma (AA) (n = 14) and typical adenoma (TA) (n = 17), as defined by standardized histopathological criteria. Exons and exon-intron boundaries of the CDC73 gene were sequenced to identify germline or somatic mutations.

Smad7 inhibits differentiation and mineralization of mouse osteoblastic cells.

The transforming growth factor (TGF)-β family members, bone morphogenetic protein (BMP)-2 and TGF-β that signal via the receptor-regulated Smads (R-Smads) induce bone formation in vivo. The inhibitory Smads (I-Smads), Smad6 and Smad7, negatively regulate TGF-β family ligand signaling by competing with R-Smads for binding to activated type I receptors, and preventing R-Smad activation, Hence, the I-Smads potentially act as suppressors of bone formation although their effects on phenotypic changes in mature osteoblasts are unclear. While Smad7 inhibits both BMP and TGF-β signaling, Smad6 is less effective in inhibiting TGF-β signaling.

Interaction of Tmem119 and the bone morphogenetic protein pathway in the commitment of myoblastic into osteoblastic cells.

Bone morphogenetic proteins (BMPs) are critical for bone regeneration and induce ectopic bone formation in vivo. The constitutively activating mutation (R206H) of the BMP type 1 receptor, activin A type 1 receptor/activin-like kinase 2 (ACVR1/ALK2), underlies the molecular pathogenesis of fibrodysplasia ossificans progressiva (FOP) in which heterotopic ossification occurs in muscle tissue. In the present study, we performed a comparative DNA microarray analysis between stable empty vector- and ALK2(R206H)-transfected mouse myoblastic C2C12 cells.

Impaired transforming growth factor-β (TGF-β) transcriptional activity and cell proliferation control of a menin in-frame deletion mutant associated with multiple endocrine neoplasia type 1 (MEN1).

Multiple endocrine neoplasia type 1 (MEN1) is characterized by tumors of the parathyroid, enteropancreas, and anterior pituitary. The MEN1 gene encodes the tumor suppressor menin of 610 amino acids that has multiple protein partners and activities. The particular pathways that, when lost, lead to tumorigenesis are not known.