Quantitative proteomics analysis of sporadic parathyroid adenoma tissue samples

Sporadic parathyroid adenoma: an updated review of molecular genetics

Introduction

Primary HPT (PHPT) is a common disorder, affecting approximately 1% of the general population. Parathyroid adenomas emerge as non-familial sporadic in 90% of cases. The aim of this review is to give a detailed update of molecular genetics of sporadic parathyroid adenoma reported in international literature.

Methods

A bibliographic research was conducted in PubMed, Google Scholar, and Scopus.

Results

Seventy-eight articles were included in our review. CaSR, MEN1, CCND1/PRAD, CDKI, angiogenic factors like VEGF, FGF, TGFβ, and IGF1, and apoptotic factors are important genes in parathyroid adenomas pathogenesis that have been established by several studies. A huge list of proteins is differently expressed in parathyroid adenomas measured by Western Blotting, MALDI/TOF, MS spectrometry, and immunohistochemistry. These proteins take part in several cell processes such as cell metabolism, cytoskeleton structural stability, cell oxidative stress regulation, cell death, transcription, translation, cell connection, and cell signaling transmission, while they can be found over- or underexpressed in abnormal tissues.

Conclusion

This review gives a detailed analysis of all reported data on genomics and proteomics of parathyroid adenoma. Further studies should be applied on understanding parathyroid adenoma pathogenesis and introducing new biomarkers for early detection of primary hyperparathyroidism.

Hormones Secretion and Rho GTPases in Neuroendocrine Tumors

Neuroendocrine tumors (NETs) belong to a heterogeneous group of neoplasms arising from hormone secreting cells. These tumors are often associated with a dysfunction of their secretory activity. Neuroendocrine secretion occurs through calcium-regulated exocytosis, a process that is tightly controlled by Rho GTPases family members. In this review, we compiled the numerous mutations and modification of expression levels of Rho GTPases or their regulators (Rho guanine nucleotide-exchange factors and Rho GTPase-activating proteins) that have been identified in NETs. We discussed how they might regulate neuroendocrine secretion.

Dysregulated mitogen-activated protein kinase pathway mediated cell cycle disruption in sporadic parathyroid tumors

OBJECTIVES

The study was designed to evaluate expression profiling of mitogen-activated protein kinase (MAPK) signalling pathway genes in sporadic parathyroid adenoma.

METHODS

Expression of MAPK signalling pathway genes including activated transcription factors and cell cycle regulatory genes was analysed by real-time PCR- based array in parathyroid adenoma (N = 20) and normal parathyroid tissue (N = 4).

RESULTS

MAPK signalling pathway as studied by PCR array revealed that a total of 22 genes were differentially expressed (≥ twofold change, p ≤ 0.05) in parathyroid adenoma. Up-regulated genes were ARAF, MAPK12, CREBBP, MYC, HSPB1, HRAS, CDK4, CCND1, and E2F1, and down-regulated genes were MAP4K1, DLK1, MAP3K4, MAPK10, MAPK8, ATF2, SMAD4, MEF2C, LAMTOR3, FOS, CDKN2A CDKN2B, and RB1. The present study revealed that ERK1/2 signalling pathway with up-regulation of HRAS, ARAF, and MEK1 genes and up-regulation of positive regulators of cell cycle (CCND1, CDK4, and E2F1) and down-regulation negative regulators of cell cycle (CDKN2A, CDKN2B, and RB1) made highly dysregulated MAPK signalling pathway in parathyroid adenoma. Expression of CDK4 was positively associated with plasma PTH level (r = 0.60, p = 0.04) and tumor weight (r = 0.80, p = 0.02) of the adenoma patients, respectively. Expression of CDKN2A was correlated negatively with PTH level (r = - 0.52, p = 0.04) of the adenoma patients.

CONCLUSION

The current study revealed that ERK pathway and associated cell cycle regulator genes are dysregulated in sporadic parathyroid adenoma.