G Protein-coupled Receptors in Radioiodine-refractory Thyroid Cancer in the Era of Precision Medicine

CONTEXT

Radioiodine-refractory thyroid cancers have poor outcomes and limited therapeutic options (tyrosine kinase inhibitors) due to transient efficacy and toxicity of treatments. Therefore, combinatorial treatments with new therapeutic approaches are needed. Many studies link G protein-coupled receptors (GPCRs) to cancer cell biology.

OBJECTIVE

To perform a specific atlas of GPCR expression in progressive and refractory thyroid cancer to identify potential targets among GPCRs aiming at drug repositioning.

METHODS

We analyzed samples from tumor and normal thyroid tissues from 17 patients with refractory thyroid cancer (12 papillary thyroid cancers [PTCs] and 5 follicular thyroid cancers [FTCs]). We assessed GPCR mRNA expression using NanoString technology with a custom panel of 371 GPCRs. The data were compared with public repositories and pharmacological databases to identify eligible drugs. The analysis of prognostic value of genes was also performed with TCGA datasets.

RESULTS

With our transcriptomic analysis, 4 receptors were found to be downregulated in FTC (VIPR1, ADGRL2/LPHN2, ADGRA3, and ADGRV1). In PTC, 24 receptors were deregulated, 7 of which were also identified by bioinformatics analyses of publicly available datasets on primary thyroid cancers (VIPR1, ADORA1, GPRC5B, P2RY8, GABBR2, CYSLTR2, and LPAR5). Among all the differentially expressed genes, 22 GPCRs are the target of approved drugs and some GPCRs are also associated with prognostic factors.

DISCUSSION

For the first time, we performed GPCR mRNA expression profiling in progressive and refractory thyroid cancers. These findings provide an opportunity to identify potential therapeutic targets for drug repositioning and precision medicine in radioiodine-refractory thyroid cancer.

In vitro effects of the endocrine disruptor p,p'DDT on human choriogonadotropin/luteinizing hormone receptor signalling

Dichlorodiphenyltrichloroethane (p,p'DDT) is an endocrine-disrupting chemical (EDC). Several studies showed an association between p,p'DDT exposure and reprotoxic effects. We showed that p,p'DDT was a positive allosteric modulator of human follitropin receptor (FSHR). In contrast, we demonstrated that p,p'DDT decreased the cyclic AMP (cAMP) production induced by human choriogonadotropin (hCG). This study evaluated further the effects of p,p'DDT on Gs-, β-arrestin 2- and steroidogenesis pathways induced by hCG or luteinizing hormone (LH). We used Chinese hamster ovary cells line stably expressing hCG/LHR. The effects of 10-100 µM p,p'DDT on cAMP production and on β-arrestin 2 recruitment were measured using bioluminescence and time-resolved resonance energy transfer technology. The impact of 100 µM of p,p'DDT on steroid secretion was analysed in murine Leydig tumor cell line (mLTC-1). In cAMP assays, 100 µM p,p'DDT increased the EC₅₀ by more than 300% and reduced the maximum response of the hCG/LHR to hCG and hLH by 30%. This inhibitory effect was also found in human granulosa cells line and in mLTC-1 cells. Likewise, 100 µM p,p'DDT decreased the hCG- and hLH-promoted β-arrestin 2 recruitment down to 14.2 and 26.6%, respectively. Moreover, 100 µM p,p'DDT decreased by 30 and 47% the progesterone secretion induced by hCG or hLH, respectively, without affecting testosterone secretion. This negative effect of p,p'DDT was independent of cytotoxicity. p,p'DDT acted as a negative allosteric modulator of the hCG/LHR signalling. This emphasizes the importance of analyzing all receptor-downstream pathways to fully understand the deleterious effects of EDC on human health.

MON-287 Expression of Programmed Death-Ligand 1 (PD-L1) in Human Pituitary Neuroendocrine Tumor

Introduction

Some Pituitary NeuroEndocrine Tumors (PitNET) present an aggressive evolution and are resistant to standard management. Immunotherapy have shown durable efficacy in a variety of malignancies. The aim of this study was to explore the programmed death-ligand 1 (PD-L1) expression in varied subtypes of pituitary adenomas with assessment of their clinical behavior at diagnosis and follow-up.

Methods

We conducted a retrospective monocentric study, including all patients operated a PitNET between 2012 and 2018. PDL-1 immunostaining were performed using an European Conformity-In-Vitro-Diagnostic labeled anti-PDL1 antibody (Clone 22C3). PD-L1 immunostaining was evaluated as the percentage of tumor cell showing positive membrane staining, into four grades: grade 0 = <1%, grade 1 = 1 to 5%, grade 2 = 6 to 49% and grade 3 = ≥ 50%. PD-L1 expression was compared with tumor features (secretion, proliferation, invasion) and outcome.

Results

The study included one hundred and thirty-nine PitNET, including 84 (60%) nonfunctioning adenomas. Twenty-five PitNET were PD-L1 positive (18%), including 3 grade 3, 8 grade 2 and 14 grade 1. PD-L1 expression was not different between functioning and non-functioning adenomas (p=0.26). Among sixteen tumors with proliferative markers (Ki-67 ≥ 3% and p53 positive), only one was PD-L1 positive.

Conclusion

In our series, pituitary tumors rarely exhibit PD-L1 expression and this immune marker did not seem to be associated with any biological characteristic or behavior of the pituitary tumors. Thus, PD-L1 staining is necessary before considering PD-L1 blockage in PitNET, in case of therapeutic impasse.

Human amniotic fluid-based exposure levels of phthalates and bisphenol A mixture reduce INSL3/RXFP2 signaling

BACKGROUND

The presence of chemical pollutants in the environment can affect human health. Epidemiological and in vivo experimental studies reveal reprotoxic effects (undescended testis) of phthalates (diethylhexyl phthalate (DEHP), dibutyl phthalate (DBP)) and bisphenol A (BPA), resulting in particular of a decrease in INSL3 (Insulin-Like 3 peptide) production. This hormone is essential for normal testis development and acts on a G protein-coupled receptor: RXFP2.

OBJECTIVES

The aim of this study was to evaluate the individual and combined impacts of DEHP, DBP, and BPA on human RXFP2 (hRXFP2) activity.

METHODS

We used HEK293 cells transiently transfected with hRXFP2 and receptor activity was analyzed by measuring intracellular cAMP production. The mixture was established at concentrations reported in human amniotic fluid, for the three compounds.

RESULTS

Individually, DEHP, DBP and BPA increased the response to INSL3 by 19.3 to 27.5%. This potentiating effect was specific for RXFP2, because it was absent in the cells which did not express this receptor. On the other hand, and interestingly, the mixture of the three compounds reduced significantly the response to INSL3 by 12%, and the observed effects were opposite to those predicted, suggesting an antagonist effect.

DISCUSSION-CONCLUSION

Taken together, our results demonstrate for the first time that a mixture of phthalates and BPA present in human amniotic fluid disturbs the human RXFP2 function. Moreover, we demonstrate that mixture can produce potential antagonistic effects that are not displayed by the compounds, individually.

Association between sleep disturbances, fear of hypoglycemia and psychological well-being in adults with type 1 diabetes mellitus, data from cross-sectional VARDIA study

AIM

To assess the relationship between sleep quality, fear of hypoglycemia, glycemic variability and psychological well-being in type 1 diabetes mellitus.

METHODS

Our data were provided by the VARDIA Study, a multicentric cross-sectional study conducted between June and December 2015. Sleep characteristics were assessed by the Pittsburgh Sleep Quality Index (PSQI). Fear of hypoglycemia and psychological well-being were measured with the Hypoglycemia Fear Survey version II (HFS-II) and the Hospital Anxiety and Depression Scale (HADS), respectively. Glycemic variability (GV) was determined using the CV of three 7-point self-monitoring blood glucose profiles and the mean amplitude of glycemic excursion (MAGE).

RESULTS

315 patients were eligible for PSQI questionnaire analysis: 54% women, mean age 47 ± 15, mean diabetes duration of 24 ± 13 years, HbA1c of 7.6 ± 0.9% (60 ± 7,5mmol/mol). Average PSQI score was 6.0 ± 3.3 and 59.8% of the patients had a PSQI score > 5. HFS-II score and HADS were significantly higher among "poor" sleepers (p < 0.0001) and PSQI score was positively associated with HADS (β = 0.22; 95% CI = 0.08;0.35). GV evaluated by CV or MAGE did not differ between "poor" and "good" sleepers (p = 0.28 and 0.54, respectively).

CONCLUSIONS

Adult patients with type 1 diabetes have sleep disturbances which correlate with psychological well-being. This study suggests that psychological management can be a target to improve sleep quality in adults with type 1 diabetes mellitus.