transforming-growth-factor-beta and Parathyroid-Neoplasms

Primary hyperparathyroidism is a common disorder that involves the pathological enlargement of one or more parathyroid glands resulting in excessive production of parathyroid hormone (PTH). The exact pathogenesis of this disease remains to be fully understood. In recent years interest has focussed on the interaction between menin protein and the transforming growth factor (TGF)-beta/Smad signalling pathway. In vitro experimentation has demonstrated that the presence of menin is required for TGF-beta to effectively inhibit parathyroid cell proliferation and PTH production. This observation correlates with the almost universal occurrence of parathyroid tumors accompanying the inactivation of menin in multiple endocrine neoplasia Type 1 (MEN1) syndrome and the high rate of somatic menin gene mutations seen in sporadic parathyroid adenomas. This chapter aims to review the role of menin in primary hyperparathyroidism and parathyroid hormone-regulation, including the influences of MEN1 gene mutations on parathyroid cell proliferation, differentiation and tumorigenesis.

Topics: Humans; Hyperparathyroidism, Primary; Multiple Endocrine Neoplasia Type 1; Mutation; Parathyroid Glands; Parathyroid Hormone; Parathyroid Neoplasms; Proto-Oncogene Proteins; Signal Transduction; Smad Proteins; Transforming Growth Factor beta

HGF (Hepatocyte Growth Factor), TGFbeta1 (Transforming Growth Factor beta1) and IGF-I (Insulin Like Growth Factor I) are cytokines that are involved in the parathyroid tumors formation and growth. We tried to determine, if there are changes and relationships in the production of these cytokines by tumor cells of parathyroid tumors.. We determined concentrations of HGF, TGFbeta1 and IGF-I in serum from peripheral blood of 16 patients with parathyroid adenoma and of 8 patients with parathyroid secondary hyperplasia before and after parathyroidectomy. Results were compared with serum levels in healthy people.. Both preoperative and postoperative HGF serum levels in patients with parathyroid adenoma and secondary hyperplasia are significantly higher than in healthy people. Preoperative and postoperative serum levels of TGFbeta1 in parathyroid adenoma and postoperative TGFb1 serum levels in parathyroid secondary hyperplasia are higher, compared with those in the healthy population and in parathyroid secondary hyperplasia preoperatively. There are no significant differences of IGF-I serum levels among the all investigated groups of patients.. Changes in the growth factors production by parathyroid tumor cells are reflected by their concentrations in peripheral blood. The elevation of HGF serum levels in patients with parathyroid adenoma and hyperplasia can be explained by very high HGF production by tumor cells. Nevertheless, there is no decrease of HGF serum levels after the parathyroidectomy. That may be the result of the extratumoral production of this cytokine. Also TGFbeta1 and IGF-I serum levels indicate high possibility of the extratumoral production of these cytokines. Higher postoperative IGF-I serum levels (but not significantly) in parathyroid secondary hyperplasia are in accordance with its bone production.

Topics: Adenoma; Cytokines; Hepatocyte Growth Factor; Humans; Hyperplasia; Insulin-Like Growth Factor I; Parathyroid Glands; Parathyroid Neoplasms; Reference Values; Transforming Growth Factor beta

Sporadic tumors of the pituitary, parathyroids and adrenal cortex are unique, as their benign forms are very common, but malignant forms are exceptionally rare. Hereditary forms of these tumors occur in multiple endocrine neoplasia syndrome type 1 (MEN1). We hypothesize that the pathogenic link among the sporadic tumors of these organs of different germ layers might be represented by common molecular pathways involving the MEN1 gene and microRNAs (miR). miR-24 might be a microRNA linking the three tumor entities, but other candidates such as miR-142-3p and microRNAs forming the DLK1-MEG3 miRNA cluster might also be of importance.

Topics: Adrenal Cortex Neoplasms; Calcium-Binding Proteins; Cell Transformation, Neoplastic; Computational Biology; Gene Expression Profiling; Humans; Intercellular Signaling Peptides and Proteins; Membrane Proteins; MicroRNAs; Models, Theoretical; Multigene Family; Multiple Endocrine Neoplasia Type 1; Mutation; Parathyroid Neoplasms; Pituitary Gland; Pituitary Neoplasms; Proto-Oncogene Proteins; RNA, Long Noncoding; Smad3 Protein; Transforming Growth Factor beta

The study investigated cyclin D1 regulation by growth factors and calcium sensing receptor (CaSR) in human tumoral parathyroid cells. Basic fibroblast and epidermal growth factors increased cyclin D1 and phosphorylated extracellular signal-regulated kinases (pERK1/2) levels that were both efficiently inhibited by CaSR agonists. By contrast, in growth factors-free medium cyclin D1 levels were either unaffected or stimulated by CaSR activation independently from ERK1/2 pathway. Transforming growth factor beta (TGFbeta) reduced cyclin D1 levels in the majority of tumors, this effect being not influenced by CaSR activation and menin expression levels. In conclusion, in parathyroid tumors cyclin D1 expression was modulated by growth factors and CaSR activation. These data further support the oncogenic role of cyclin D1, which resulted to be target for stimulation by bFGF and EGF and inhibition by CaSR and TGFbeta signalling in the parathyroid.

Topics: Cyclin D1; DNA Methylation; Gene Expression Regulation, Neoplastic; Humans; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Models, Biological; Parathyroid Glands; Parathyroid Neoplasms; Phosphorylation; Proto-Oncogene Proteins; Receptors, Calcium-Sensing; Receptors, Retinoic Acid; Signal Transduction; Transforming Growth Factor beta

In some patients with multiple endocrine neoplasia type 1 (MEN1) it is not possible to identify a germline mutation in the MEN1 gene. We sought to document the loss of expression and function of the MEN1 gene product, menin, in the tumors of such a patient. The proband is an elderly female patient with primary hyperparathyroidism, pancreatic islet tumor, and breast cancer. Her son has primary hyperparathyroidism. No germline MEN1 mutation was identified in the proband or her son. However, loss of heterozygosity at the MEN1 locus and complete lack of menin expression were demonstrated in the proband's tumor tissue. The proband's cultured parathyroid cells lacked the normal reduction in proliferation and parathyroid hormone secretion in response to transforming growth factor- beta. This assessment provided insight into the molecular pathogenesis of the patient and provides evidence for a critical requirement for menin in the antiproliferative action of transforming growth factor-beta.

Topics: Aged; Chromosomes, Human, Pair 11; Female; Germ-Line Mutation; Humans; Hypercalcemia; Hyperthyroidism; Liver Neoplasms; Loss of Heterozygosity; Microsatellite Repeats; Multiple Endocrine Neoplasia Type 1; Parathyroid Hormone; Parathyroid Neoplasms; Polymorphism, Genetic; Proto-Oncogene Proteins; Transforming Growth Factor beta; Tumor Cells, Cultured

Based upon molecular allelotyping and comparative genomic hybridization studies, chromosome 15q is the likely location of a tumor suppressor gene important in the pathogeneses of sporadic enteropancreatic endocrine tumors and parathyroid adenomas. Interest has focused on Smad3 as a candidate endocrine tumor suppressor gene because 1) it is localized to 15q and 2) it encodes a TGF beta signaling molecule that has been identified as a binding partner of the multiple endocrine neoplasm type 1 gene product menin, itself involved in enteropancreatic and parathyroid neoplasia. To determine whether Smad3 plays a primary role in development of these tumors, 20 enteropancreatic tumors and 67 parathyroid adenomas were investigated for loss of heterozygosity at DNA markers surrounding Smad3. Twenty percent of enteropancreatic tumors and 24% of parathyroid adenomas showed loss. All 9 coding exons and intron-exon boundaries of the Smad3 gene were then sequenced in genomic DNA from all 20 enteropancreatic and 25 parathyroid tumors, including every case with loss of heterozygosity. No acquired clonal mutations, insertions, or microdeletions in Smad3 were detected in any tumors. Because inactivating somatic mutation is the hallmark of an authentic tumor suppressor, Smad3 is unlikely to function as a classical tumor suppressor gene in the pathogenesis of sporadic parathyroid or enteropancreatic endocrine tumors.

Topics: Adenoma; DNA Mutational Analysis; DNA-Binding Proteins; Genes, Tumor Suppressor; Humans; Islets of Langerhans; Neoplasm Proteins; Pancreatic Neoplasms; Parathyroid Neoplasms; Polymorphism, Genetic; Proto-Oncogene Proteins; Smad3 Protein; Trans-Activators; Transforming Growth Factor beta