"Expression and prognostic relevance of PD-1, PD-L1 and CTLA-4 immune checkpoints in adrenocortical carcinoma".

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with poor prognosis in advanced stages. While therapies targeting the checkpoint molecules programmed cell death 1 (PD-1), its ligand PD-L1 and the cytotoxic T lymphocyte-associated protein 4 (CTLA-4) have revolutionized treatment in many cancers, the results in ACC were heterogeneous. Their expression in ACC has not been systematically studied and might explain the variable response to checkpoint inhibitors. The expression of PD-1, PD-L1 and CTLA-4 was examined in 162 tumor samples from 122 ACC patients by immunohistochemistry (threshold of >1%) and correlated with tumoral T lymphocyte infiltration and clinical endpoints. Finally, uni- and multivariate analyses of progression-free and overall survival were performed. PD-1 and PD-L1 were expressed in 26.5% and 24.7% of samples, respectively, with low expression in most tumor samples (median positive cells: 2.1% and 21.7%. In contrast, CTLA-4 expression was observed in 52.5% of ACC with a median of 38.4% positive cells. Positive PD-1 expression was associated with longer progression-free survival (HR: 0.50, 95% CI 0.25-0.98, p=0.04) even after considering prognostic factors. In contrast, PD-L1 and CTLA-4 did not correlate with clinical outcome. Additionally, PD-1 and PD-L1 expression correlated significantly with the amount of CD3+, CD4+, FoxP3+ and CD8+ T cells. The heterogeneous expression of PD1, PD-L1, and CTLA-4 in this large series of well-annotated ACC samples might explain the heterogeneous results of the immunotherapies in advanced ACC. In addition, PD-1 expression is a strong prognostic biomarker that can easily be applied in routine clinical care and histopathological assessment.

Loss of LGR4/GPR48 causes severe neonatal salt wasting due to disrupted WNT signaling altering adrenal zonation.

Disorders of isolated mineralocorticoid deficiency, which cause potentially life-threatening salt-wasting crisis early in life, have been associated with gene variants of aldosterone biosynthesis or resistance; however, in some patients no such variants are found. WNT/ß-catenin signaling is crucial for differentiation and maintenance of the aldosterone-producing adrenal zona glomerulosa (zG). Herein, we describe a highly consanguineous family with multiple perinatal deaths and infants presenting at birth with failure to thrive, severe salt-wasting crises associated with isolated hypoaldosteronism, nail anomalies, short stature, and deafness. Whole exome sequencing revealed a homozygous splice variant in the R-SPONDIN receptor LGR4 gene (c.618-1G>C) regulating WNT signaling. The resulting transcripts affected protein function and stability and resulted in loss of Wnt/ß-catenin signaling in vitro. The impact of LGR4 inactivation was analyzed by adrenal cortex-specific ablation of Lgr4, using Lgr4fl/fl mice mated with Sf1:Cre mice. Inactivation of Lgr4 within the adrenal cortex in the mouse model caused decreased WNT signaling, aberrant zonation with deficient zG, and reduced aldosterone production. Thus, human LGR4 mutations establish a direct link between LGR4 inactivation and decreased canonical WNT signaling, which results in abnormal zG differentiation and endocrine function. Therefore, variants in WNT signaling and its regulators should systematically be considered in familial hyperreninemic hypoaldosteronism.

Loss of SUMO-specific protease 2 causes isolated glucocorticoid deficiency by blocking adrenal cortex zonal transdifferentiation in mice.

SUMOylation is a dynamic posttranslational modification, that provides fine-tuning of protein function involved in the cellular response to stress, differentiation, and tissue development. In the adrenal cortex, an emblematic endocrine organ that mediates adaptation to physiological demands, the SUMOylation gradient is inversely correlated with the gradient of cellular differentiation raising important questions about its role in functional zonation and the response to stress. Considering that SUMO-specific protease 2 (SENP2), a deSUMOylating enzyme, is upregulated by Adrenocorticotropic Hormone (ACTH)/cAMP-dependent Protein Kinase (PKA) signalling within the zona fasciculata, we generated mice with adrenal-specific Senp2 loss to address these questions. Disruption of SENP2 activity in steroidogenic cells leads to specific hypoplasia of the zona fasciculata, a blunted reponse to ACTH and isolated glucocorticoid deficiency. Mechanistically, overSUMOylation resulting from SENP2 loss shifts the balance between ACTH/PKA and WNT/ß-catenin signalling leading to repression of PKA activity and ectopic activation of ß-catenin. At the cellular level, this blocks transdifferentiation of ß-catenin-positive zona glomerulosa cells into fasciculata cells and sensitises them to premature apoptosis. Our findings indicate that the SUMO pathway is critical for adrenal homeostasis and stress responsiveness.

Sexually dimorphic activation of innate antitumor immunity prevents adrenocortical carcinoma development.

Unlike most cancers, adrenocortical carcinomas (ACCs) are more frequent in women than in men, but the underlying mechanisms of this sexual dimorphism remain elusive. Here, we show that inactivation of Znrf3 in the mouse adrenal cortex, recapitulating the most frequent alteration in ACC patients, is associated with sexually dimorphic tumor progression. Although female knockouts develop metastatic carcinomas at 18 months, adrenal hyperplasia regresses in male knockouts. This male-specific phenotype is associated with androgen-dependent induction of senescence, recruitment, and differentiation of highly phagocytic macrophages that clear out senescent cells. In contrast, in females, macrophage recruitment is delayed and dampened, which allows for aggressive tumor progression. Consistently, analysis of TCGA-ACC data shows that phagocytic macrophages are more prominent in men and are associated with better prognosis. Together, these data show that phagocytic macrophages are key players in the sexual dimorphism of ACC that could be previously unidentified allies in the fight against this devastating cancer.