Dataset Information

Ex Vivo Intact Tissue Analysis Reveals Alternative Calcium-sensing Behaviors in Parathyroid Adenomas.

ABSTRACT:

Context

The biochemical basis for clinical variability in primary hyperparathyroidism (PHPT) is poorly understood.

Objective

This study aimed to define parathyroid tumor biochemical properties associated with calcium-sensing failure in PHPT patients, and to relate differences in these profiles to variations in clinical presentation.

Methods

Preoperative clinical data from a sequential series of 39 patients undergoing surgery for PHPT at an endocrine surgery referral center in a large, public university hospital were evaluated for correlation to parathyroid tumor biochemical behavior. An intact tissue, ex vivo interrogative assay was employed to evaluate the calcium-sensing capacity of parathyroid adenomas relative to normal donor glands. Tumors were functionally classified based on calcium dose-response curve profiles, and clinical parameters were compared among the respective classes. Changes in the relative expression of 3 key components in the calcium/parathyroid hormone (PTH) signaling axis-CASR, RGS5, and RCAN1-were evaluated as potential mechanisms for calcium-sensing failure.

Results

Parathyroid adenomas grouped into 3 distinct functional classes. Tumors with diminished calcium sensitivity were the most common (18 of 39) and were strongly associated with reduced bone mineral density (P = 0.0009). Tumors with no calcium-sensing deficit (11 of 39) were associated with higher preoperative PTH (P = 0.036). A third group (6/39) displayed a nonsigmoid calcium/PTH response curve; 4 of these 6 tumors expressed elevated RCAN1.

Conclusion

Calcium-sensing capacity varies among parathyroid tumors but downregulation of the calcium-sensing receptor (CASR) is not an obligate underlying mechanism. Differences in tumor calcium responsiveness may contribute to variations in PHPT clinical presentation.

SUBMITTER: Koh J

PROVIDER: S-EPMC8530711 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature

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Publications

Ex Vivo Intact Tissue Analysis Reveals Alternative Calcium-sensing Behaviors in Parathyroid Adenomas.

Koh James J Zhang Run R Roman Sanziana S Duh Quan-Yang QY Gosnell Jessica J Shen Wen W Suh Insoo I Sosa Julie A JA

The Journal of clinical endocrinology and metabolism 20211001 11

<h4>Context</h4>The biochemical basis for clinical variability in primary hyperparathyroidism (PHPT) is poorly understood.<h4>Objective</h4>This study aimed to define parathyroid tumor biochemical properties associated with calcium-sensing failure in PHPT patients, and to relate differences in these profiles to variations in clinical presentation.<h4>Methods</h4>Preoperative clinical data from a sequential series of 39 patients undergoing surgery for PHPT at an endocrine surgery referral center ...[more]

PMID: 34272844

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Project description:The functional impact of intratumoral heterogeneity has been difficult to assess in the absence of a means to interrogate dynamic, live-cell biochemical events in the native tissue context of a human tumor. Conventional histological methods can reveal morphology and static biomarker expression patterns but do not provide a means to probe and evaluate tumor functional behavior and live-cell responsiveness to experimentally controlled stimuli. Here, we describe an approach that couples vibratome-mediated viable tissue sectioning with live-cell confocal microscopy imaging to visualize human parathyroid adenoma tumor cell responsiveness to extracellular calcium challenge. Tumor sections prepared as 300 micron-thick tissue slices retain viability throughout a >24 hour observation period and retain the native architecture of the parental tumor. Live-cell observation of biochemical signaling in response to extracellular calcium challenge in the intact tissue slices reveals discrete, heterogeneous kinetic waveform categories of calcium agonist reactivity within each tumor. Plotting the proportion of maximally responsive tumor cells as a function of calcium concentration yields a sigmoid dose-response curve with a calculated calcium EC50 value significantly elevated above published reference values for wild-type calcium-sensing receptor (CASR) sensitivity. Subsequent fixation and immunofluorescence analysis of the functionally evaluated tissue specimens allows alignment and mapping of the physical characteristics of individual cells within the tumor to specific calcium response behaviors. Evaluation of the relative abundance of intracellular PTH in tissue slices challenged with variable calcium concentrations demonstrates that production of the hormone can be dynamically manipulated ex vivo. The capability of visualizing live human tumor tissue behavior in response to experimentally controlled conditions opens a wide range of possibilities for personalized ex vivo therapeutic testing. This highly adaptable system provides a unique platform for live-cell ex vivo provocative testing of human tumor responsiveness to a range of physiological agonists or candidate therapeutic compounds.

Project description:Primary hyperparathyroidism is a common endocrine disorder frequently affecting postmenopausal women. In this study we have investigated expression of the prolactin receptor (PRLr) in a panel of 37 sporadic parathyroid tumours, as well as functionality in vitro in cultured parathyroid tumour cells. High levels of the prolactin receptor gene (PRLR) transcripts were demonstrated in parathyroid tissues as compared to other reference tissues and breast cancer cells. PRLr products of 60/70 kDa were highly expressed in all parathyroid tumours. In addition varying levels of the 80 kDa PRLr isoform, with known proliferative activity, were demonstrated. In parathyroid tumours PRLr immunoreactivity was observed in cytoplasm in all cases and in addition in the plasma membrane (n = 12) or enlarged lysosomes (n = 4). In normal parathyroid rim PRLr was expressed in cytoplasm and granulae. In in vitro studies of short-term cultured human parathyroid tumour cells prolactin stimulation was associated with transcriptional changes in JAK/STAT, RIG-I like receptor and type II interferon signaling pathways as documented by gene expression profiling. Moreover, PRLR gene expression in parathyroid tumors was significantly inversely correlated with plasma total Ca2+ levels. In conclusion, the prolactin receptor was found highly abundant in human parathyroid gland, parathyroid tumours, correlated with patient Ca2+ levels and functionally responsive to physiological levels of prolactin. These findings suggest a role for the prolactin receptor in human parathyroid adenomas. Expression profiling was done in parathyroid adenomas subjected to prolactin treatment in culture. In addition, corresponding paraffin sections were obtained for verification of PRLr expression by immunohistochemistry. 200 mg/L prolactin (recombinant human prolactin, Cat. No. JM-4687-50, MBL Woburn, MA) was added to 1× 10^6 attached parathyroid tumour cells. Cells were harvested using RNAlater (QIAGEN) and homogenized with QIAshredder for RNA extraction after 3 h and 24 h in culture, respectively. Negative controls were collected in parallel with each case at the same time points. RNA was extracted using QIA Cube, and quality assessed with Bioanalyser and Nanodrop. Expression array profiling and data analysis was done at the KI core facility Bioinformatics and Expression Analysis (BEA, Novum, Huddinge) using the Affymetrix platform and the TITAN ST 1.1 array. A total of 16 samples were analysed including 4 parathyroid adenomas cultured for 3 h or 24 h in the presence of prolactin plus control samples cultured in parallel without prolactin.

Dataset Information

Ex Vivo Intact Tissue Analysis Reveals Alternative Calcium-sensing Behaviors in Parathyroid Adenomas.

Context

Objective

Methods

Results

Conclusion

Publications

Ex Vivo Intact Tissue Analysis Reveals Alternative Calcium-sensing Behaviors in Parathyroid Adenomas.

Similar Datasets

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