Cellular landscape of adrenocortical carcinoma at single-nuclei resolution

Adrenocortical carcinoma (ACC) is a rare yet devastating tumour of the adrenal gland with a molecular pathology that remains incompletely understood. To gain novel insights into the cellular landscape of ACC, we generated single-nuclei RNA sequencing (snRNA-seq) data sets from twelve ACC tumour samples and analysed these alongside snRNA-seq data sets from normal adrenal glands (NAGs). We find the ACC tumour microenvironment to be relatively devoid of immune cells compared to NAG tissues, consistent with known high tumour purity values for ACC as an immunologically "cold" tumour. Our analysis identifies three separate groups of ACC samples that are characterised by different relative compositions of adrenocortical cell types. These include cell populations that are specifically enriched in the most clinically aggressive and hormonally active tumours, displaying hallmarks of reorganised cell mechanobiology and dysregulated steroidogenesis, respectively. We also identified and validated a population of mitotically active adrenocortical cells that strongly overexpress genes POLQ, DIAPH3 and EZH2 to support tumour expansion alongside an LGR4+ progenitor-like or cell-of-origin candidate for adrenocortical carcinogenesis. Trajectory inference suggests the fate adopted by malignant adrenocortical cells upon differentiation is associated with the copy number or allelic balance state of the imprinted DLK1/MEG3 genomic locus, which we verified by assessing bulk tumour DNA methylation status. In conclusion, our results therefore provide new insights into the clinical and cellular heterogeneity of ACC, revealing how genetic perturbations to healthy adrenocortical renewal and zonation provide a molecular basis for disease pathogenesis.

"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.

Erythropoiesis in Cushing syndrome: sex-related and subtype-specific differences. Results from a monocentric study

CONTEXT

Cushing syndrome (CS) is associated with different hematological abnormalities. Nevertheless, conflicting data about erythropoiesis in CS have been reported. Furthermore, it is unclear whether CS sex and subtype-specific alterations in red blood cells (RBC) parameters are present.

OBJECTIVE

To investigate sex and subtype-specific changes in RBC in patients with CS at initial diagnosis and after remission.

DESIGN

Retrospective, monocentric study including 210 patients with CS (women, n = 162) matched 1:1 for sex and age to patients with pituitary microadenomas or adrenal incidentalomas (both hormonally inactive). RBC parameters were evaluated at initial diagnosis and after remission.

RESULTS

Women with CS had higher hematocrit (median 42.2 vs 39.7%), hemoglobin (14.1 vs 13.4 g/dl) and mean corpuscular volume (MCV) (91.2 vs 87.9 fl) compared to the controls (all p < 0.0001). Women with Cushing disease (CD) showed higher hematocrit, RBC and hemoglobin levels than those with ectopic Cushing (ECS) (all p < 0.005). Men with CS had lower hematocrit (42.9 vs 44.7%), RBC count (4.8 vs 5.1n*106/µl) and hemoglobin (14.2 vs 15.4 g/dl), but higher MCV (90.8 vs 87.5 fl) than controls (all p < 0.05). In men with CS, no subtype-specific differences were identified. Three months after remission hemoglobin decreased in both sexes.

CONCLUSION

CS is characterized by sexual and subtype-specific differences in RBC parameters. Compared to controls, women with CS showed higher hematocrit/hemoglobin levels, whereas men had lower hematocrit/hemoglobin, which further decreased directly after remission. Therefore, anemia should be considered as complication of CS in men. In women, differences in RBC parameters may help to differentiate CD from ECS.

PPARG dysregulation as a potential molecular target in adrenal Cushing's syndrome

Background

We performed a transcriptomic analysis of adrenal signaling pathways in various forms of endogenous Cushing's syndrome (CS) to define areas of dysregulated and druggable targets.

Methodology

Next-generation sequencing was performed on adrenal samples of patients with primary bilateral macronodular adrenal hyperplasia (PBMAH, n=10) and control adrenal samples (n=8). The validation groups included cortisol-producing adenoma (CPA, n=9) and samples from patients undergoing bilateral adrenalectomy for Cushing's disease (BADX-CD, n=8). In vivo findings were further characterized using three adrenocortical cell-lines (NCI-H295R, CU-ACC2, MUC1).

Results

Pathway mapping based on significant expression patterns identified PPARG (peroxisome proliferator-activated receptor gamma) pathway as the top hit. Quantitative PCR (QPCR) confirmed that PPARG (l2fc<-1.5) and related genes - FABP4 (l2fc<-5.5), PLIN1 (l2fc<-4.1) and ADIPOQ (l2fc<-3.3) - were significantly downregulated (p<0.005) in PBMAH. Significant downregulation of PPARG was also found in BADX-CD (l2fc<-1.9, p<0.0001) and CPA (l2fc<-1.4, p<0.0001). In vitro studies demonstrated that the PPARG activator rosiglitazone resulted in decreased cell viability in MUC1 and NCI-H295R (p<0.0001). There was also a significant reduction in the production of aldosterone, cortisol, and cortisone in NCI-H295R and in Dihydrotestosterone (DHT) in MUC1 (p<0.05), respectively.

Outcome

This therapeutic effect was independent of the actions of ACTH, postulating a promising application of PPARG activation in endogenous hypercortisolism.

High Filamin a Expression in Adrenocortical Carcinomas Is Associated with a Favourable Tumour Behaviour: A European Multicentric Study

The insulin-like growth factor 2 (IGF2) promotes cell growth by overactivating the IGF system in an autocrine loop in adrenocortical carcinomas (ACCs). The cytoskeleton protein filamin A (FLNA) acts as a repressor of IGF2 mitogenic signalling in ACC cells. The aims of this study were to test FLNA expression by immunohistochemistry in 119 ACCs and 26 adrenocortical adenomas (ACAs) and to evaluate its relationship with clinicopathological features and outcome in ACCs. We found that 71.4% of ACCs did not express FLNA, whereas FLNA absence was a rare event in ACAs (15.4%, p < 0.001 vs. ACCs). In addition, the expression of FLNA was associated with a less aggressive tumour behaviour in ACCs. Indeed, the subgroup of ACCs with high FLNA showed a lower ENSAT stage, Weiss score, and S-GRAS score compared to ACCs with low FLNA expression (p < 0.05). Moreover, patients with high FLNA had a longer overall survival than those with low FLNA (p < 0.05). In conclusion, our data suggest that FLNA may represent a "protective" factor in ACCs, and the integration of FLNA immunohistochemical expression in ACC tissues along with other clinical and molecular markers could be helpful to improve diagnostic accuracy and prognosis prediction in ACCs.

FGF/FGFR signaling in adrenocortical development and tumorigenesis: novel potential therapeutic targets in adrenocortical carcinoma

FGF/FGFR signaling regulates embryogenesis, angiogenesis, tissue homeostasis and wound repair by modulating proliferation, differentiation, survival, migration and metabolism of target cells. Understandably, compelling evidence for deregulated FGF signaling in the development and progression of different types of tumors continue to emerge and FGFR inhibitors arise as potential targeted therapeutic agents, particularly in tumors harboring aberrant FGFR signaling. There is first evidence of a dual role of the FGF/FGFR system in both organogenesis and tumorigenesis, of which this review aims to provide an overview. FGF-1 and FGF-2 are expressed in the adrenal cortex and are the most powerful mitogens for adrenocortical cells. Physiologically, they are involved in development and maintenance of the adrenal gland and bind to a family of four tyrosine kinase receptors, among which FGFR1 and FGFR4 are the most strongly expressed in the adrenal cortex. The repeatedly proven overexpression of these two FGFRs also in adrenocortical cancer is thus likely a sign of their participation in proliferation and vascularization, though the exact downstream mechanisms are not yet elucidated. Thus, FGFRs potentially offer novel therapeutic targets also for adrenocortical carcinoma, a type of cancer resistant to conventional antimitotic agents.

Subtype-specific pattern of white blood cell differential in endogenous hypercortisolism

OBJECTIVE

Endogenous hypercortisolism predisposes to impaired immune function and infections. To date, however, it is unknown whether there is a subtype-specific pattern in white blood cell (WBC) and WBC differential (WBCD) count.

METHODS

A retrospective monocentric cohort study was carried out in patients with overt endogenous Cushing's syndrome (CS) or adrenal incidentalomas and autonomous cortisol secretion (ACS), with WBC/WBCD analysis at initial diagnosis and after biochemical remission. Cut-offs were obtained by receiver-operating characteristics analysis.

RESULTS

In total, 253 patients were analyzed (Cushing's disease (CD); n = 88; ectopic CS (ECS), n = 31; cortisol-producing adrenal adenomas (CPA), n = 40; ACS, n = 45; adrenocortical carcinomas (ACC), n = 49). Total leukocytes and neutrophils correlated positively with serum cortisol after 1-mg dexamethasone (r = 0.314 and r = 0.428), while a negative correlation was observed for lymphocytes and eosinophils (r = -0.374 and r= -0.380) (each P < 0.0001). Similar observations were made for 24 h-urinary free cortisol. CD and ECS differed in numbers of neutrophils and lymphocytes (P < 0.0001) and were well differentiated at a cut-off of 6.1 for the neutrophil/lymphocyte ratio (sensitivity 90.0%, specificity 89.4%, and areas under the curve (AUC) 0.918). For adrenocorticotropic hormone (ACTH)-independent CS, the best diagnostic outcome was obtained for the discrimination of CPA and ACC at a cut-off of 187.9 for the platelet/lymphocyte ratio (sensitivity 59.6%, specificity 80.6%, and AUC 0.713). For ECS, CPA, and CD, neutrophils decreased (delta -47.0, -29.7, and -26.2%) and lymphocytes increased (+123.2, +78.1, and +17.7%) already 3 months after remission.

CONCLUSION

Most immune cells correlate with the degree of hypercortisolism and differ among CS subtypes. WBCD changes are already identified 3 months after remission from endogenous hypercortisolism.

MicroRNAs and Long Non-Coding RNAs in Adrenocortical Carcinoma

Non-coding RNAs (ncRNAs) are a type of genetic material that do not encode proteins but regulate the gene expression at an epigenetic level, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). The role played by ncRNAs in many physiological and pathological processes has gained attention during the last few decades, as they might be useful in the diagnosis, treatment and management of several human disorders, including endocrine and oncological diseases. Adrenocortical carcinoma (ACC) is a rare and aggressive endocrine cancer, still characterized by high mortality and morbidity due to both endocrine and oncological complications. Despite the rarity of this disease, recently, the role of ncRNA has been quite extensively evaluated in ACC. In order to better explore the role of the ncRNA in human ACC, this review summarizes the current knowledge on ncRNA dysregulation in ACC and its potential role in the diagnosis, treatment, and management of this tumor.

Characterization of Adrenal miRNA-Based Dysregulations in Cushing's Syndrome

MiRNAs are important epigenetic players with tissue- and disease-specific effects. In this study, our aim was to investigate the putative differential expression of miRNAs in adrenal tissues from different forms of Cushing’s syndrome (CS). For this, miRNA-based next-generation sequencing was performed in adrenal tissues taken from patients with ACTH-independent cortisol-producing adrenocortical adenomas (CPA), from patients with ACTH-dependent pituitary Cushing’s disease (CD) after bilateral adrenalectomy, and from control subjects. A confirmatory QPCR was also performed in adrenals from patients with other CS subtypes, such as primary bilateral macronodular hyperplasia and ectopic CS. Sequencing revealed significant differences in the miRNA profiles of CD and CPA. QPCR revealed the upregulated expression of miR-1247-5p in CPA and PBMAH (log2 fold change > 2.5, p < 0.05). MiR-379-5p was found to be upregulated in PBMAH and CD (log2 fold change > 1.8, p < 0.05). Analyses of miR-1247-5p and miR-379-5p expression in the adrenals of mice which had been exposed to short-term ACTH stimulation showed no influence on the adrenal miRNA expression profiles. For miRNA-specific target prediction, RNA-seq data from the adrenals of CPA, PBMAH, and control samples were analyzed with different bioinformatic platforms. The analyses revealed that both miR-1247-5p and miR-379-5p target specific genes in the WNT signaling pathway. In conclusion, this study identified distinct adrenal miRNAs as being associated with CS subtypes.

SOAT1: A Suitable Target for Therapy in High-Grade Astrocytic Glioma?

Targeting molecular alterations as an effective treatment for isocitrate dehydrogenase-wildtype glioblastoma (GBM) patients has not yet been established. Sterol-O-Acyl Transferase 1 (SOAT1), a key enzyme in the conversion of endoplasmic reticulum cholesterol to esters for storage in lipid droplets (LD), serves as a target for the orphan drug mitotane to treat adrenocortical carcinoma. Inhibition of SOAT1 also suppresses GBM growth. Here, we refined SOAT1-expression in GBM and IDH-mutant astrocytoma, CNS WHO grade 4 (HGA), and assessed the distribution of LD in these tumors. Twenty-seven GBM and three HGA specimens were evaluated by multiple GFAP, Iba1, IDH1 R132H, and SOAT1 immunofluorescence labeling as well as Oil Red O staining. To a small extent SOAT1 was expressed by tumor cells in both tumor entities. In contrast, strong expression was observed in glioma-associated macrophages. Triple immunofluorescence labeling revealed, for the first time, evidence for SOAT1 colocalization with Iba1 and IDH1 R132H, respectively. Furthermore, a notable difference in the amount of LD between GBM and HGA was observed. Therefore, SOAT1 suppression might be a therapeutic option to target GBM and HGA growth and invasiveness. In addition, the high expression in cells related to neuroinflammation could be beneficial for a concomitant suppression of protumoral microglia/macrophages.

Steroid profiling using liquid chromatography mass spectrometry during adrenal vein sampling in patients with primary bilateral macronodular adrenocortical hyperplasia

INTRODUCTION

Adrenal vein sampling (AVS) is not a routine procedure in patients with primary bilateral macronodular adrenocortical hyperplasia (PBMAH), but has been used to determine lateralization of cortisol secretion in order to guide decision of unilateral adrenalectomy. Our aim was to characterize the steroid fingerprints in AVS samples of patients with PBMAH and hypercortisolism and to identify a reference hormone for AVS interpretation.

METHOD

Retrospectively, we included 17 patients with PBMAH from the German Cushing's registry who underwent AVS. 15 steroids were quantified in AVS and peripheral blood samples using LC-MS/MS. We calculated lateralization indices and conversion ratios indicative of steroidogenic enzyme activity to elucidate differences between individual adrenal steroidomes and in steroidogenic pathways.

RESULTS

Adrenal volume was negatively correlated with peripheral cortisone (r=0.62, p<0.05). 24-hour urinary free cortisol correlated positively with peripheral androgens (rDHEA=0.57, rDHEAS=0.82, rA=0.73, rT=0.54, p<0.05). DHEA was found to be a powerful reference hormone with high selectivity index, which did not correlate with serume cortisol and has a short half-life. All investigated steroids showed lateralization in single patients indicating the heterogenous steroid secretion pattern in patients with PBMAH. The ratios of corticosterone/aldosterone (catalyzed by CYP11B2), androstenedione/dehydroepiandrosterone (catalyzed by HSD3B2) and cortisone/cortisol (catalyzed by HSD11B2) in adrenal vein samples were higher in smaller adrenals (p<0.05). ARMC5 mutation carriers (n=6) showed lower androstenedione/17-hydroxyprogesterone and higher testosterone/androstenedione (p<0.05) ratios in peripheral blood, in line with lower peripheral androstenedione concentrations (p<0.05).

CONCLUSION

Steroid profiling by LC-MS/MS led us to select DHEA as a candidate reference hormone for cortisol secretion. Lateralization and different steroid ratios showed that each steroid and all three steroidogenic pathways may be affected in PBMAH patients. In patients with germline ARMC5 mutations, the androgen pathway was particularly dysregulated.

High expression of Sterol-O-Acyl transferase 1 (SOAT1), an enzyme involved in cholesterol metabolism, is associated with earlier biochemical recurrence in high risk prostate cancer

Background

Prostate cancer (PCa) is the most frequent cancer in men. The prognosis of PCa is heterogeneous with many clinically indolent tumors and rare highly aggressive cases. Reliable tissue markers of prognosis are lacking. Active cholesteryl ester synthesis has been associated with prostate cancer aggressiveness. Sterol-O-Acyl transferases (SOAT) 1 and 2 catalyze cholesterol esterification in humans.

Objective

To investigate the value of SOAT1 and SOAT2 tissue expression as prognostic markers in high risk PCa.

Patients and methods

Formalin-fixed paraffin-embedded tissue samples from 305 high risk PCa cases treated with radical prostatectomy were analyzed for SOAT1 and SOAT2 protein expression by semi-quantitative immunohistochemistry. The Kaplan–Meier method and Cox proportional hazards modeling were used to compare outcome.

Main outcome measure

Biochemical recurrence (BCR) free survival.

Results

SOAT1 expression was high in 73 (25%) and low in 219 (75%; not evaluable: 13) tumors. SOAT2 was highly expressed in 40 (14%) and at low levels in 249 (86%) samples (not evaluable: 16). By Kaplan–Meier analysis, we found significantly shorter median BCR free survival of 93 months (95% confidence interval 23.6–123.1) in patients with high SOAT1 vs. 134 months (112.6–220.2, Log-rank p < 0.001) with low SOAT1. SOAT2 expression was not significantly associated with BCR. After adjustment for age, preoperative PSA, tumor stage, Gleason score, resection status, lymph node involvement and year of surgery, high SOAT1 but not SOAT2 expression was associated with shorter BCR free survival with a hazard ratio of 2.40 (95% CI 1.57–3.68, p < 0.001). Time to clinical recurrence and overall survival were not significantly associated with SOAT1 and SOAT2 expression

Conclusions

SOAT1 expression is strongly associated with BCR free survival alone and after multivariable adjustment in high risk PCa. SOAT1 may serve as a histologic marker of prognosis and holds promise as a future treatment target.

A novel patient-derived cell line of adrenocortical carcinoma shows a pathogenic role of germline MUTYH mutation and high tumour mutational burden

BACKGROUND

The response of advanced adrenocortical carcinoma (ACC) to current chemotherapies is unsatisfactory and a limited rate of response to immunotherapy was observed in clinical trials. High tumour mutational burden (TMB) and the presence of a specific DNA signature are characteristic features of tumours with mutations in the gene MUTYH encoding the mutY DNA glycosylase. Both have been shown to potentially predict the response to immunotherapy. High TMB in an ACC cell line model has not been reported yet.

DESIGN AND METHODS

The JIL-2266 cell line was established from a primary ACC tumour, comprehensively characterised and oxidative damage, caused by a dysfunctional mutY DNA glycosylase, confirmed.

RESULTS

Here, we characterise the novel patient-derived ACC cell line JIL-2266, which is deficient in mutY-dependent DNA repair. JIL-2266 cells have a consistent STR marker profile that confirmed congruousness with primary ACC tumour. Cells proliferate with a doubling time of 41 ± 13 h. Immunohistochemistry revealed positivity for steroidogenic factor-1. Mass spectrometry did not demonstrate significant steroid hormone synthesis. JIL-2266 have hemizygous mutations in the tumour suppressor gene TP53 (c.859G>T:p.E287X) and MUTYH (c.316C>T:p.R106W). Exome sequencing showed 683 single nucleotide variants and 4 insertions/deletions. We found increased oxidative DNA damage in the cell line and the corresponding primary tumour caused by impaired mutY DNA glycosylase function and accumulation of 8-oxoguanine.

CONCLUSION

This model will be valuable as a pre-clinical ACC cell model with high TMB and a tool to study oxidative DNA damage in the adrenal gland.

Epithelial and Mesenchymal Markers in Adrenocortical Tissues: How Mesenchymal Are Adrenocortical Tissues?

A clinically relevant proportion of adrenocortical carcinoma (ACC) cases shows a tendency to metastatic spread. The objective was to determine whether the epithelial to mesenchymal transition (EMT), a mechanism associated with metastasizing in several epithelial cancers, might play a crucial role in ACC. 138 ACC, 29 adrenocortical adenomas (ACA), three normal adrenal glands (NAG), and control tissue samples were assessed for the expression of epithelial (E-cadherin and EpCAM) and mesenchymal (N-cadherin, SLUG and SNAIL) markers by immunohistochemistry. Using real-time RT-PCR we quantified the alternative isoform splicing of FGFR 2 and 3, another known indicator of EMT. We also assessed the impact of these markers on clinical outcome. Results show that both normal and neoplastic adrenocortical tissues lacked expression of epithelial markers but strongly expressed mesenchymal markers N-cadherin and SLUG. FGFR isoform splicing confirmed higher similarity of adrenocortical tissues to mesenchymal compared to epithelial tissues. In ACC, higher SLUG expression was associated with clinical markers indicating aggressiveness, while N-cadherin expression inversely associated with these markers. In conclusion, we could not find any indication of EMT as all adrenocortical tissues lacked expression of epithelial markers and exhibited closer similarity to mesenchymal tissues. However, while N-cadherin might play a positive role in tissue structure upkeep, SLUG seems to be associated with a more aggressive phenotype.

Interplay between glucocorticoids and tumor-infiltrating lymphocytes on the prognosis of adrenocortical carcinoma

Background

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy. Tumor-related glucocorticoid excess is present in ~60% of patients and associated with particularly poor prognosis. Results of first clinical trials using immune checkpoint inhibitors were heterogeneous. Here we characterize tumor-infiltrating T lymphocytes (TILs) in ACC in association with glucocorticoids as potential explanation for resistance to immunotherapy.

Methods

We performed immunofluorescence analysis to visualize tumor-infiltrating T cells (CD3⁺), T helper cells (CD3⁺CD4⁺), cytotoxic T cells (CD3⁺CD8⁺) and regulatory T cells (Tregs; CD3⁺CD4⁺FoxP3⁺) in 146 ACC tissue specimens (107 primary tumors, 16 local recurrences, 23 metastases). Quantitative data of immune cell infiltration were correlated with clinical data (including glucocorticoid excess).

Results

86.3% of ACC specimens showed tumor infiltrating T cells (7.7 cells/high power field (HPF)), including T helper (74.0%, 6.7 cells/HPF), cytotoxic T cells (84.3%, 5.7 cells/HPF) and Tregs (49.3%, 0.8 cells/HPF). The number of TILs was associated with better overall survival (HR for death: 0.47, 95% CI 0.25 to 0.87), which was true for CD4⁺− and CD8⁺ subpopulations as well. In localized, non-metastatic ACC, the favorable impact of TILs on overall and recurrence-free survival was manifested even independently of ENSAT (European Network for the Study of Adrenal Tumors) stage, resection status and Ki67 index. T helper cells were negatively correlated with glucocorticoid excess (Phi=−0.290, p=0.009). Patients with glucocorticoid excess and low TILs had a particularly poor overall survival (27 vs. 121 months in patients with TILs without glucocorticoid excess).

Conclusion

Glucocorticoid excess is associated with T cell depletion and unfavorable prognosis. To reactivate the immune system in ACC by checkpoint inhibitors, an inhibition of adrenal steroidogenesis might be pivotal and should be tested in prospective studies.

Corticotroph tumor progression after bilateral adrenalectomy (Nelson's syndrome): systematic review and expert consensus recommendations

BACKGROUND

Corticotroph tumor progression (CTP) leading to Nelson's syndrome (NS) is a severe and difficult-to-treat complication subsequent to bilateral adrenalectomy (BADX) for Cushing's disease. Its characteristics are not well described, and consensus recommendations for diagnosis and treatment are missing.

METHODS

A systematic literature search was performed focusing on clinical studies and case series (≥5 patients). Definition, cumulative incidence, treatment and long-term outcomes of CTP/NS after BADX were analyzed using descriptive statistics. The results were presented and discussed at an interdisciplinary consensus workshop attended by international pituitary experts in Munich on October 28, 2018.

RESULTS

Data covered definition and cumulative incidence (34 studies, 1275 patients), surgical outcome (12 studies, 187 patients), outcome of radiation therapy (21 studies, 273 patients), and medical therapy (15 studies, 72 patients).

CONCLUSIONS

We endorse the definition of CTP-BADX/NS as radiological progression or new detection of a pituitary tumor on thin-section MRI. We recommend surveillance by MRI after 3 months and every 12 months for the first 3 years after BADX. Subsequently, we suggest clinical evaluation every 12 months and MRI at increasing intervals every 2-4 years (depending on ACTH and clinical parameters). We recommend pituitary surgery as first-line therapy in patients with CTP-BADX/NS. Surgery should be performed before extrasellar expansion of the tumor to obtain complete and long-term remission. Conventional radiotherapy or stereotactic radiosurgery should be utilized as second-line treatment for remnant tumor tissue showing extrasellar extension.

Circulating microRNA Expression in Cushing's Syndrome

Context

Cushing's syndrome (CS) is a rare disease of endogenous hypercortisolism associated with high morbidity and mortality. Diagnosis and classification of CS is still challenging.

Objective

Circulating microRNAs (miRNAs) are minimally invasive diagnostic markers. Our aim was to characterize the circulating miRNA profiles of CS patients and to identify distinct profiles between the two major CS subtypes.

Methods

We included three groups of patients from the German Cushing's registry: ACTH-independent CS (Cortisol-Producing-Adenoma; CPA), ACTH-dependent pituitary CS (Cushing's Disease; CD), and patients in whom CS had been ruled out (controls). Profiling of miRNAs was performed by next-generation-sequencing (NGS) in serum samples of 15 CS patients (each before and after curative surgery) and 10 controls. Significant miRNAs were first validated by qPCR in the discovery cohort and then in an independent validation cohort of 20 CS patients and 11 controls.

Results

NGS identified 411 circulating miRNAs. Differential expression of 14 miRNAs were found in the pre- and postoperative groups. qPCR in the discovery cohort validated 5 of the significant miRNAs from the preoperative group analyses. Only, miR-182-5p was found to be significantly upregulated in the CD group of the validation cohort. Comparing all CS samples as a group with the controls did not reveal any significant differences in expression.

Outcome

In conclusion, our study identified miR-182-5p as a possible biomarker for CD, which has to be validated in a prospective cohort. Furthermore, our results suggest that presence or absence of ACTH might be at least as relevant for miRNA expression as hypercortisolism itself.

PKA Cα subunit mutation triggers caspase-dependent RIIβ subunit degradation via Ser114 phosphorylation

Mutations in the PRKACA gene are the most frequent cause of cortisol-producing adrenocortical adenomas leading to Cushing's syndrome. PRKACA encodes for the catalytic subunit α of protein kinase A (PKA). We already showed that PRKACA mutations lead to impairment of regulatory (R) subunit binding. Furthermore, PRKACA mutations are associated with reduced RIIβ protein levels; however, the mechanisms leading to reduced RIIβ levels are presently unknown. Here, we investigate the effects of the most frequent PRKACA mutation, L206R, on regulatory subunit stability. We find that Ser¹¹⁴ phosphorylation of RIIβ is required for its degradation, mediated by caspase 16. Last, we show that the resulting reduction in RIIβ protein levels leads to increased cortisol secretion in adrenocortical cells. These findings reveal the molecular mechanisms and pathophysiological relevance of the R subunit degradation caused by PRKACA mutations, adding another dimension to the deregulation of PKA signaling caused by PRKACA mutations in adrenal Cushing's syndrome.

Case Report: Consecutive Adrenal Cushing's Syndrome and Cushing's Disease in a Patient With Somatic CTNNB1, USP8, and NR3C1 Mutations

The occurrence of different subtypes of endogenous Cushing's syndrome (CS) in single individuals is extremely rare. We here present the case of a female patient who was successfully cured from adrenal CS 4 years before being diagnosed with Cushing's disease (CD). The patient was diagnosed at the age of 50 with ACTH-independent CS and a left-sided adrenal adenoma, in January 2015. After adrenalectomy and histopathological confirmation of a cortisol-producing adrenocortical adenoma, biochemical hypercortisolism and clinical symptoms significantly improved. However, starting from 2018, the patient again developed signs and symptoms of recurrent CS. Subsequent biochemical and radiological workup suggested the presence of ACTH-dependent CS along with a pituitary microadenoma. The patient underwent successful transsphenoidal adenomectomy, and both postoperative adrenal insufficiency and histopathological workup confirmed the diagnosis of CD. Exome sequencing excluded a causative germline mutation but showed somatic mutations of the β-catenin protein gene (CTNNB1) in the adrenal adenoma, and of both the ubiquitin specific peptidase 8 (USP8) and the glucocorticoid receptor (NR3C1) genes in the pituitary adenoma. In conclusion, our case illustrates that both ACTH-independent and ACTH-dependent CS may develop in a single individual even without evidence for a common genetic background.

Single-cell molecular profiling of all three components of the HPA axis reveals adrenal ABCB1 as a regulator of stress adaptation

Chronic activation and dysregulation of the neuroendocrine stress response have severe physiological and psychological consequences, including the development of metabolic and stress-related psychiatric disorders. We provide the first unbiased, cell type-specific, molecular characterization of all three components of the hypothalamic-pituitary-adrenal axis, under baseline and chronic stress conditions. Among others, we identified a previously unreported subpopulation of Abcb1b+ cells involved in stress adaptation in the adrenal gland. We validated our findings in a mouse stress model, adrenal tissues from patients with Cushing's syndrome, adrenocortical cell lines, and peripheral cortisol and genotyping data from depressed patients. This extensive dataset provides a valuable resource for researchers and clinicians interested in the organism's nervous and endocrine responses to stress and the interplay between these tissues. Our findings raise the possibility that modulating ABCB1 function may be important in the development of treatment strategies for patients suffering from metabolic and stress-related psychiatric disorders.

Role of FGF Receptors and Their Pathways in Adrenocortical Tumors and Possible Therapeutic Implications

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy and treatment of advanced disease is challenging. Clinical trials with multi-tyrosine kinase inhibitors in the past have yielded disappointing results. Here, we investigated fibroblast growth factor (FGF) receptors and their pathways in adrenocortical tumors as potential treatment targets. We performed real-time RT-PCR of 93 FGF pathway related genes in a cohort of 39 fresh frozen benign and malignant adrenocortical, 9 non-adrenal tissues and 4 cell lines. The expression of FGF receptors was validated in 166 formalin-fixed paraffin embedded (FFPE) tissues using RNA in situ hybridization (RNAscope) and correlated with clinical data. In malignant compared to benign adrenal tumors, we found significant differences in the expression of 16/94 FGF receptor pathway related genes. Genes involved in tissue differentiation and metastatic spread through epithelial to mesechymal transition were most strongly altered. The therapeutically targetable FGF receptors 1 and 4 were upregulated 4.6- and 6-fold, respectively, in malignant compared to benign adrenocortical tumors, which was confirmed by RNAscope in FFPE samples. High expression of FGFR1 and 4 was significantly associated with worse patient prognosis in univariate analysis. After multivariate adjustment for the known prognostic factors Ki-67 and ENSAT tumor stage, FGFR1 remained significantly associated with recurrence-free survival (HR=6.10, 95%CI: 1.78 - 20.86, p=0.004) and FGFR4 with overall survival (HR=3.23, 95%CI: 1.52 - 6.88, p=0.002). Collectively, our study supports a role of FGF pathways in malignant adrenocortical tumors. Quantification of FGF receptors may enable a stratification of ACC for the use of FGFR inhibitors in future clinical trials.

RNA Sequencing and Somatic Mutation Status of Adrenocortical Tumors: Novel Pathogenetic Insights

CONTEXT

Pathogenesis of autonomous steroid secretion and adrenocortical tumorigenesis remains partially obscure.

OBJECTIVE

To investigate the relationship between transcriptome profile and genetic background in a large series of adrenocortical tumors and identify new potential pathogenetic mechanisms.

DESIGN

Cross-sectional study.

SETTING

University Hospitals of the European Network for the Study of Adrenal Tumors (ENSAT).

PATIENTS

We collected snap-frozen tissue from patients with adrenocortical tumors (n = 59) with known genetic background: 26 adenomas with Cushing syndrome (CS- cortisol-producing adenoma [CPA]), 17 adenomas with mild autonomous cortisol secretion (MACS-CPAs), 9 endocrine-inactive adenomas (EIAs), and 7 adrenocortical carcinomas (ACCs).

INTERVENTION

Ribonucleic acid (RNA) sequencing.

MAIN OUTCOME MEASURES

Gene expression, long noncoding RNA (lncRNA) expression, and gene fusions. Correlation with genetic background defined by targeted Sanger sequencing, targeted panel- or whole-exome sequencing.

RESULTS

Transcriptome analysis identified 2 major clusters for adenomas: Cluster 1 (n = 32) mainly consisting of MACS-CPAs with CTNNB1 or without identified driver mutations (46.9% of cases) and 8/9 EIAs; Cluster 2 (n = 18) that comprised CP-CPAs with or without identified driver mutation in 83.3% of cases (including all CS-CPAs with PRKACA mutation). Two CS-CPAs, 1 with CTNNB1 and 1 with GNAS mutation, clustered separately and relatively close to ACC. lncRNA analysis well differentiate adenomas from ACCs. Novel gene fusions were found, including AKAP13-PDE8A in one CS-CPA sample with no driver mutation.

CONCLUSIONS

MACS-CPAs and EIAs showed a similar transcriptome profile, independently of the genetic background, whereas most CS-CPAs clustered together. Still unrevealed molecular alterations in the cAMP/PKA or Wnt/beta catenin pathways might be involved in the pathogenesis of adrenocortical tumors.

Steroidogenesis in the NCI-H295 Cell Line Model is Strongly Affected By Culture Conditions and Substrain

CONTEXT

NCI-H295 cells are the most widely used model for adrenal steroidogenesis and adrenocortical carcinoma and have been used for decades in laboratories worldwide. However, reported steroidogenic properties differ considerably.

OBJECTIVE

To evaluate heterogeneity of steroidogenesis among NCI-H295 cell strains, clarify the influence of culture media and test response to inhibitors of steroidogenesis by using liquid chromatography tandem mass spectrometry (LC-MS/MS).

METHODS

NCI-H295 cells were obtained from two cell banks and cultivated in different media. An LC-MS/MS-based panel analysis of thirteen steroids was adapted for cell culture supernatant. Cells were treated with metyrapone, abiraterone and mitotane.

RESULTS

Mineralocorticoid synthesis was strongly affected by passaging as reflected by reduction of aldosterone secretion from 0.158±0.006 to 0.017±0.001 µg/106 cells (p<0.05). Relevant differences were also found for cells from two vendors in terms of aldosterone secretion (0.180±0.001 vs. 0.09±0.002 µg/106 cells, p<0.05). Selection of medium strongly impacted on cortisol secretion with>4-fold difference (40.6±5.5 vs. 182.1±23 µg/106 cells) and reflected differential activation of the glucocorticoid pathway. Exposure to abiraterone, metyrapone and mitotane resulted in characteristic steroidogenic profiles consistent with known mechanism of drug action with considerable differences in metabolites upstream of the blocked enzyme.

CONCLUSION

We demonstrate that steroid hormone secretion in NCI-H295 cells is strongly affected by the individual strain, passage and growing conditions. These factors should be taken into account in the evaluation of experiments analyzing steroid parameters directly or as surrogate parameters of cell viability.

Expression of SOAT1 in Adrenocortical Carcinoma and Response to Mitotane Monotherapy: An ENSAT Multicenter Study

CONTEXT

Objective response rate to mitotane in advanced adrenocortical carcinoma (ACC) is approximately 20%, and adverse drug effects are frequent. To date, there is no marker established that predicts treatment response. Mitotane has been shown to inhibit sterol-O-acyl transferase 1 (SOAT1), which leads to endoplasmic reticulum stress and cell death in ACC cells.

OBJECTIVE

To investigate SOAT1 protein expression as a marker of treatment response to mitotane.

PATIENTS

A total of 231 ACC patients treated with single-agent mitotane as adjuvant (n = 158) or advanced disease therapy (n = 73) from 12 ENSAT centers were included. SOAT1 protein expression was determined by immunohistochemistry on formalin-fixed paraffin-embedded specimens.

SETTING

Retrospective study at 12 ACC referral centers.

MAIN OUTCOME MEASURE

Recurrence-free survival (RFS), progression-free survival (PFS), and disease-specific survival (DSS).

RESULTS

Sixty-one of 135 patients (45%) with adjuvant mitotane treatment had recurrences and 45/68 patients (66%) with mitotane treatment for advanced disease had progressive disease. After multivariate adjustment for sex, age, hormone secretion, tumor stage, and Ki67 index, RFS (hazard ratio [HR] = 1.07; 95% confidence interval [CI], 0.61-1.85; P = 0.82), and DSS (HR = 1.30; 95% CI, 0.58-2.93; P = 0.53) in adjuvantly treated ACC patients did not differ significantly between tumors with high and low SOAT1 expression. Similarly, in the advanced stage setting, PFS (HR = 1.34; 95% CI, 0.63-2.84; P = 0.45) and DSS (HR = 0.72; 95% CI, 0.31-1.70; P = 0.45) were comparable and response rates not significantly different.

CONCLUSIONS

SOAT1 expression was not correlated with clinical endpoints RFS, PFS, and DSS in ACC patients with mitotane monotherapy. Other factors appear to be relevant for mitotane treatment response and ACC patient survival.

SUN-211 Active Steroid Hormone Synthesis Renders Adrenocortical Cells Highly Susceptible to Type II Ferroptosis Induction

Context: Cell death in the adrenal cortex is ill understood but of high clinical relevance. Resistance of adrenocortical carcinoma (ACC) to current treatment with mitotane and chemotherapy calls for an improved understanding of adrenal cortical cell death processes. Ferroptosis is an iron-dependent form of regulated cell death which is characterized by polyunsaturated lipids adrenic (AdA) and arachidonic acid (AA) peroxidation. Aim: To address the potential role of ferroptosis in the adrenal gland as a potential treatment target of ACC. Methods: Human ACC cells H295R, CU-ACC1 and 2 were used. Protein expression of key enzymes was determined by western blotting. Lipid peroxidation was quantified with BODIPY 581/591 and cell viability with CellTiterGlo after treatment with known inducers and inhibitors of ferroptosis and steroidogenesis, respectively. Results: Adrenocortical tissues are enriched in AdA and AA and express high levels of genes relevant to ferroptosis, such as glutathione peroxidase 4 (GPX4) and long-chain-fatty-acid CoA ligase 4 (ACSL4). Inhibition of GPX4 with RSL3 led to cell death in H295R, CU-ACC1 and 2 cells at EC₅₀ values of 2.4x10^-7, 8.1x10^-7 and 1.5x10^-8 M, respectively. The steroidogenesis inhibitor ketoconazole completely reversed RSL3 cytotoxicity in all three steroidogenic cell lines by reducing lipid peroxidation. Mitotane induced lipid peroxidation but inhibition of ferroptosis with liproxstatin did not protect mitotane-induced cell death. Conclusion: Adrenocortical cells are highly sensitive to ferroptosis due to active steroidogenesis. Triggering this form of cell death could present future novel treatment options against ACC.

Early Postoperative Circulating miR-483-5p Is a Prognosis Marker for Adrenocortical Cancer

We have previously identified serum miR-483-5p as a preoperative diagnosis and prognosis biomarker for adrenocortical cancer (ACC). Here, we aimed to determine whether circulating miR-483-5p levels measured 3 months post-operatively distinguished patients with good prognosis (no recurrence for at least 3 years; NR3yrs) from patients with poor prognosis (recurrence or death within 3 years after surgery; R < 3yrs). We conducted a single-center retrospective analysis using sera from 48 patients with ACC that were initially non-metastatic and treated by surgery. Sera sampled within 3 months after surgery were available in 26 patients. MiR-483-5p absolute circulating levels were measured using quantitative PCR. Thirteen patients showed a recurrence before 3 years (=R < 3yrs). Thirteen patients showed no recurrence within 3 years, including 11 patients with a follow-up longer than 3 years (=NR3yrs). Serum miR-483-5p levels were higher in R < 3yrs than in NR3yrs: 1,541,990 ± 428,377 copies/mL vs. 388,457 ± 62,169 copies/mL (p = 0.002). Receiver operating characteristic analysis showed that a value of 752,898 copies/mL distinguished R < 3yrs from NR3yrs with 61.5% sensitivity (CI 31.6-86.1) and 100% specificity (CI 71.5-100) with an area under the curve of 0.853. Patients with a value below this threshold had a significantly longer recurrence-free and overall survival. In multivariate analysis, miR-483-5p provided the single best prognostic value for recurrence-free survival (RFS) (hazard ratio (HR) for recurrence 5.98, p < 0.011) but not for overall survival. Our study suggests that serum miR-483-5p is a potent early post-operative biomarker for ACC prognosis that might be a better predictor of RFS than currently used markers.

Cancer-testis Antigen FATE1 Expression in Adrenocortical Tumors Is Associated with A Pervasive Autoimmune Response and Is A Marker of Malignancy in Adult, but Not Children, ACC

The SF-1 transcription factor target gene FATE1 encodes a cancer-testis antigen that has an important role in regulating apoptosis and response to chemotherapy in adrenocortical carcinoma (ACC) cells. Autoantibodies directed against FATE1 were previously detected in patients with hepatocellular carcinoma. In this study, we investigated the prevalence of circulating anti-FATE1 antibodies in pediatric and adult patients with adrenocortical tumors using three different methods (immunofluorescence, ELISA and Western blot). Our results show that a pervasive anti-FATE1 immune response is present in those patients. Furthermore, FATE1 expression is a robust prognostic indicator in adult patients with ACC and is associated with increased steroidogenic and decreased immune response gene expression. These data can open perspectives for novel strategies in ACC immunotherapy.

Effects of Germline CYP2W1*6 and CYP2B6*6 Single Nucleotide Polymorphisms on Mitotane Treatment in Adrenocortical Carcinoma: A Multicenter ENSAT Study

Mitotane is the only approved drug for advanced adrenocortical carcinoma (ACC) and no biomarkers are available to predict attainment of therapeutic plasma concentrations and clinical response. Aim of the study was to evaluate the suitability of cytochrome P450(CYP)2W1 and CYP2B6 single nucleotide polymorphisms (SNPs) as biomarkers. A multicenter cohort study including 182 ACC patients (F/M = 121/61) treated with mitotane monotherapy after radical resection (group A, n = 103) or in not completely resectable, recurrent or advanced disease (group B, n = 79) was performed. CYP2W1*2, CYP2W1*6, CYP2B6*6 and CYP2B6 rs4803419 were genotyped in germline DNA. Mitotane blood levels were measured regularly. Response to therapy was evaluated as time to progression (TTP) and disease control rate (DCR). Among investigated SNPs, CYP2W1*6 and CYP2B6*6 correlated with mitotane treatment only in group B. Patients with CYP2W1*6 (n = 21) achieved less frequently therapeutic mitotane levels (>14 mg/L) than those with wild type (WT) allele (76.2% vs 51.7%, p = 0.051) and experienced shorter TTP (HR = 2.10, p = 0.019) and lower DCR (chi-square = 6.948, p = 0.008). By contrast, 55% of patients with CYP2B6*6 vs. 28.2% WT (p = 0.016) achieved therapeutic range. Combined, a higher rate of patients with CYP2W1*6WT+CYP2B6*6 (60.6%) achieved mitotane therapeutic range (p = 0.034). In not completely resectable, recurrent or advanced ACC, CYP2W1*6 SNP was associated with a reduced probability to reach mitotane therapeutic range and lower response rates, whereas CYP2B6*6 correlated with higher mitotane levels. The association of these SNPs may predict individual response to mitotane.

Targeted Gene Expression Profile Reveals CDK4 as Therapeutic Target for Selected Patients With Adrenocortical Carcinoma

Adrenocortical carcinomas (ACC) are aggressive tumors with a heterogeneous prognosis and limited therapeutic options for advanced stages. This study aims to identify novel drug targets for a personalized treatment in ACC. RNA was isolated from 40 formalin-fixed paraffin-embedded ACC samples. We evaluated gene expression of 84 known cancer drug targets by reverse transcriptase quantitative real time-PCR and calculated fold change using 5 normal adrenal glands as reference (overexpression by fold change >2.0). The most promising candidate cyclin-dependent kinase 4 (CDK4) was investigated at protein level in 104 ACC samples and tested by in vitro experiments in two ACC cell lines (NCI-H295R and MUC1). The most frequently overexpressed genes were TOP2A (100% of cases, median fold change = 16.5), IGF2 (95%, fold change = 52.9), CDK1 (80%, fold change = 6.7), CDK4 (62%, fold change = 2.6), PLK4 (60%, fold change = 2.8), and PLK1 (52%, fold change = 2.3). CDK4 was chosen for functional validation, as it is actionable by approved CDK4/6-inhibitors (e.g., palbociclib). Nuclear immunostaining of CDK4 significantly correlated with mRNA expression (R = 0.52, P < 0.005). We exposed both NCI-H295R and MUC1 cell lines to palbociclib and found a concentration- and time-dependent reduction of cell viability, which was more pronounced in the NCI-H295R cells in line with higher CDK4 expression. Furthermore, we tested palbociclib in combination with insulin-like growth factor 1/insulin receptor inhibitor linsitinib showing an additive effect. In conclusion, we demonstrate that RNA profiling is useful to discover potential drug targets and that CDK4/6 inhibitors are promising candidates for treatment of selected patients with ACC.

The New Genetic Landscape of Cushing's Disease: Deubiquitinases in the Spotlight

Cushing’s disease (CD) is a rare condition caused by adrenocorticotropic hormone (ACTH)-producing adenomas of the pituitary, which lead to hypercortisolism that is associated with high morbidity and mortality. Treatment options in case of persistent or recurrent disease are limited, but new insights into the pathogenesis of CD are raising hope for new therapeutic avenues. Here, we have performed a meta-analysis of the available sequencing data in CD to create a comprehensive picture of CD’s genetics. Our analyses clearly indicate that somatic mutations in the deubiquitinases are the key drivers in CD, namely USP8 (36.5%) and USP48 (13.3%). While in USP48 only Met415 is affected by mutations, in USP8 there are 26 different mutations described. However, these different mutations are clustering in the same hotspot region (affecting in 94.5% of cases Ser718 and Pro720). In contrast, pathogenic variants classically associated with tumorigenesis in genes like TP53 and BRAF are also present in CD but with low incidence (12.5% and 7%). Importantly, several of these mutations might have therapeutic potential as there are drugs already investigated in preclinical and clinical setting for other diseases. Furthermore, network and pathway analyses of all somatic mutations in CD suggest a rather unified picture hinting towards converging oncogenic pathways.

Driver mutations in USP8 wild-type Cushing's disease

BACKGROUND

Medical treatment in Cushing's disease (CD) is limited due to poor understanding of its pathogenesis. Pathogenic variants of ubiquitin specific peptidase 8 (USP8) have been confirmed as causative in around half of corticotroph tumors. We aimed to further characterize the molecular landscape of those CD tumors lacking USP8 mutations in a large cohort of patients.

METHODS

Exome sequencing was performed on 18 paired tumor-blood samples with wild-type USP8 status. Candidate gene variants were screened by Sanger sequencing in 175 additional samples. The most frequent variant was characterized by further functional in vitro assays.

RESULTS

Recurrent somatic hotspot mutations in another deubiquitinase, USP48, were found in 10.3% of analyzed samples. Several possibly damaging variants were found in TP53 in 6 of 18 samples. USP48 variants were associated with smaller tumors and trended toward higher frequency in female patients. They also changed the structural conformation of USP48 and increased its catalytic activity toward its physiological substrates histone 2A and zinc finger protein Gli1, as well as enhanced the stimulatory effect of corticotropin releasing hormone (CRH) on pro-opiomelanocortin production and adrenocorticotropic hormone secretion.

CONCLUSIONS

USP48 pathogenic variants are relatively frequent in USP8 wild-type tumors and enhance CRH-induced hormone production in a manner coherent with sonic hedgehog activation. In addition, TP53 pathogenic variants may be more frequent in larger CD tumors than previously reported.

Value of Molecular Classification for Prognostic Assessment of Adrenocortical Carcinoma

Importance

The risk stratification of adrenocortical carcinoma (ACC) based on tumor proliferation index and stage is limited. Adjuvant therapy after surgery is recommended for most patients. Pan-genomic studies have identified distinct molecular groups closely associated with outcome.

Objective

To compare the molecular classification for prognostic assessment of ACC with other known prognostic factors.

Design, Setting, and Participants

In this retrospective biomarker analysis, ACC tumor samples from 368 patients who had undergone surgical tumor removal were collected from March 1, 2005, to September 30, 2015 (144 in the training cohort and 224 in the validation cohort) at 21 referral centers with a median follow-up of 35 months (interquartile range, 18-74 months). Data were analyzed from March 2016 to March 2018.

Exposures

Meta-analysis of pan-genomic studies (transcriptome, methylome, chromosome alteration, and mutational profiles) was performed on the training cohort. Targeted biomarker analysis, including targeted gene expression (BUB1B and PINK1), targeted methylation (PAX5, GSTP1, PYCARD, and PAX6), and targeted next-generation sequencing, was performed on the training and validation cohorts.

Main Outcomes and Measures

Disease-free survival. Cox proportional hazards regression and C indexes were used to assess the prognostic value of each model.

Results

Of the 368 patients (mean [SD] age, 49 [16] years), 144 were in the training cohort (100 [69.4%] female) and 224 were in the validation cohort (142 [63.4%] female). In the training cohort, pan-genomic measures classified ACC into 3 molecular groups (A1, A2, and A3-B), with 5-year survival of 9% for group A1, 45% for group A2, and 82% for group A3-B (log-rank P < .001). Molecular class was an independent prognostic factor of recurrence in stage I to III ACC after complete surgery (hazard ratio, 55.91; 95% CI, 8.55-365.40; P < .001). The combination of European Network for the Study of Adrenal Tumors (ENSAT) stage, tumor proliferation index, and molecular class provided the most discriminant prognostic model (C index, 0.88). In the validation cohort, the molecular classification, determined by targeted biomarker measures, was confirmed as an independent prognostic factor of recurrence (hazard ratio, 5.96 [95% CI, 1.81-19.58], P = .003 for the targeted classifier combining expression, methylation, and chromosome alterations; and 2.61 [95% CI, 1.31-5.19], P = .006 for the targeted classifier combining methylation, chromosome alterations, and mutational profile). The prognostic value of the molecular markers was limited for patients with stage IV ACC.

Conclusions and Relevance

The findings suggest that in localized ACC, targeted classifiers may be used as independent markers of recurrence. The determination of molecular class may improve individual prognostic assessment and thus may spare unnecessary adjuvant treatment.

Prognostic Relevance of Steroid Sulfation in Adrenocortical Carcinoma Revealed by Molecular Phenotyping Using High-Resolution Mass Spectrometry Imaging

BACKGROUND

Adrenocortical carcinoma (ACC) is a rare tumor with variable prognosis even within the same tumor stage. Cancer-related sex hormones and their sulfated metabolites in body fluids can be used as tumor markers. The role of steroid sulfation in ACC has not yet been studied. MALDI mass spectrometry imaging (MALDI-MSI) is a novel tool for tissue-based chemical phenotyping.

METHODS

We performed phenotyping of formalin-fixed, paraffin-embedded tissue samples from 72 ACC by MALDI-MSI at a metabolomics level.

RESULTS

Tumoral steroid hormone metabolites-estradiol sulfate [hazard ratio (HR) 0.26; 95% CI, 0.10-0.69; P = 0.005] and estrone 3-sulfate (HR 0.22; 95% CI, 0.07-0.63; P = 0.003)-were significantly associated with prognosis in Kaplan-Meier analyses and after multivariable adjustment for age, tumor stage, and sex (HR 0.29; 95% CI, 0.11-0.79; P = 0.015 and HR 0.30; 95% CI, 0.10-0.91; P = 0.033, respectively). Expression of sulfotransferase SULT2A1 was associated with prognosis to a similar extent and was validated to be a prognostic factor in two published data sets. We discovered the presence of estradiol-17β 3,17-disulfate (E2S2) in a subset of tumors with particularly poor overall survival. Electron microscopy revealed novel membrane-delimited organelles in only these tumors. By applying cluster analyses of metabolomic data, 3 sulfation-related phenotypes exhibited specific metabolic features unrelated to steroid metabolism.

CONCLUSIONS

MALDI-MSI provides novel insights into the pathophysiology of ACC. Steroid hormone sulfation may be used for prognostication and treatment stratification. Sulfation-related metabolic reprogramming may be of relevance also in conditions beyond the rare ACC and can be directly investigated by the use of MALDI-MSI.

Impact of USP8 Gene Mutations on Protein Deregulation in Cushing Disease

CONTEXT

Cushing disease (CD) is a rare disorder with severe sequels and incompletely understood pathogenesis. The underlying corticotroph adenomas harbor frequently somatic mutations in the ubiquitin-specific peptidase 8 (USP8) gene. These mutations render USP8 hyperactive and prevent client proteins from degradation.

OBJECTIVE

To investigate the impact of USP8 mutations on proteins deregulated in CD.

DESIGN

One hundred eight pituitary adenomas (75 corticotroph [58 USP8 wild type (WT) and 17 USP8 mutated], 14 somatotroph, and 19 nonfunctioning) were investigated by immunohistochemistry. All evaluated proteins [USP8, arginine vasopressin receptor 1b and 2, corticotropin-releasing hormone receptor, cAMP response element-binding protein (CREB), p27/kip1, cyclin E, heat shock protein 90 (HSP90), orphan nuclear receptor 4, epidermal growth factor receptor, histone deacetylase 2, glucocorticoid receptor, cyclin-dependent kinase 5 and Abelson murine leukemia viral oncogene homolog 1 enzyme substrate 1] were known to be deregulated in CD. Furthermore, AtT20 cells were transfected with USP8 to investigate the expression of possible downstream proteins by immunoblot.

RESULTS

Whereas most of the investigated proteins were not differentially expressed, the cell-cycle inhibitor p27 was significantly reduced in USP8 mutated corticotroph adenoma (H-score 2.0 ± 1.0 vs 1.1 ± 1.1 in WT adenomas; P = 0.004). In contrast, the chaperone HSP90 was expressed higher (0.5 ± 0.4 vs 0.2 ± 0.4; P = 0.29), and the phosphorylation of the transcription factor CREB was increased in USP8 mutated adenomas (1.30.5 ± 0.40.9 vs 0.70.5 ± 0.40.7; P = 0.014). Accordingly, AtT20 cells transfected with the USP8 P720R mutant had higher phosphorylated CREB (pCREB) levels than WT transfected cells (1.3 ± 0.14 vs 1 ± 0.23; P = 0.13).

CONCLUSIONS

We could demonstrate that USP8 mutations are associated with deregulation of p27/kip1, HSP90, and pCREB. These findings suggest that these proteins are direct or indirect clients of USP8 and could therefore be potential targets for therapeutic approaches in patients with CD.

SAT-354 Characterization of Cell Death Induced by SOAT1 Inhibition in Adrenocortical Carcinoma Cells

Background: Mitotane is the only drug approved for treatment of adrenocortical carcinoma (ACC). We have found that mitotane inhibits Sterol-O-Acyl transferase 1 (SOAT1) which leads to depletion of cholesterol esters and increase of free cholesterol in the ACC cell line NCI-H295. We demonstrated activation of endoplasmic reticulum response pathway that resulted in decreased cell viability. Aim: To characterize the mechanisms underlying cell death resulting from SOAT1 inhibition with inhibitors mitotane, ATR101, AZD3988 and Sandoz58-035. Methods: SOAT1 inhibition was quantified in vitro, ER-stress marker expression by qPCR, cell viability by cell titer glo assay, lipid composition by GC-MS, and lipid peroxidation with BODIPY 581/591 C11. Cell death in NCIH295R cells induced by mitotane was determined by mitotane treatment alone and in combination with either the pan caspase inhibitor zvad-fmk, necroptose inhibitor necrostatin-1, ferroptosis inhibitor liproxstatin or ferroptosis activators erastin and RSL-3. Results: Mitotane and ATR101 but not AZD3988 and Sandoz58-035 induced lipid peroxidation in NCI-H295R cells in a concentration dependent manner. ATR101, AZD3988 and Sandoz58-035 were inhibitors of SOAT1 with IC₅₀ of 3 nM, 13 nM and 0.9 nM. Correspondingly, expression of ER-stress marker CHOP and splicing of X-box protein 1 mRNA was activated by mitotane, ATR101 and poorly by AZD3988. Mitotane and ATR101 but not AZD3988 and Sandoz58-035 treatment induced the accumulation of free cholesterol in NCI-H295 cells after 6h. Cell viability was impaired with mitotane, ATR101 and AZD3988 but not Sandoz58-035. None of the inhibitors could reverse the effects of mitotane while synergistic effects were observed for RSL3. Erastin was shown to reverse the effects of mitotane treatment. Conclusion: Although SOAT1 inhibition was confirmed for all compounds, downstream effects on ER-stress markers and cell viability exhibit marked differences. Hence it is likely that targets different from SOAT1 are relevant for in vitro cytotoxic activity of mitotane and ATR101. Caspases do not seem to be predominantly involved in mitotane-induced cell death. Although we observed a synergistic effect of mitotane with RSL3, ferroptosis inhibitors were not able to block mitotane-induced cell death. The precise mechanism of cell death and immunogenic cell death pathways require further investigation.

SUN-350 Sterol-O-Acyl Transferase 1 Protein Expression Alone Is Not Sufficient to Predict Response to Mitotane Treatment in Adrenocortical Carcinoma

Background: Objective response rate to mitotane in advanced ACC is only ~20% and adverse drug effects are frequent and potentially serious. Markers of treatment response are not established. We have previously discovered that mitotane is an inhibitor of sterol-O-Acyl transferase 1 (SOAT1) which leads to depletion of cholesterol esters, endoplasmic reticulum stress and cell death in the ACC cell line NCI-H295. Data from a small cohort of patients with advanced ACC treated with mitotane monotherapy suggested longer progression-free survival in patients with high SOAT1 expression in ACC tissue. Aim: To investigate SOAT1 protein expression as a marker of treatment response to mitotane. Methods: SOAT1 protein expression was semiquantitatively determined by immunohistochemistry in full sections of 223 ACC treated with mitotane monotherapy in an adjuvant (n=151) and palliative setting (n=72) from eleven ENSAT centers. Expression was classified as high (H-score ≥2) and low (H-score <2) and correlated with recurrence-free (RFS) and progression-free survival (PFS), overall survival (OS), and mitotane levels after three and six months. Results: After multivariate adjustment for sex, ENSAT stage and Ki67 index, RFS (HR=1.3, log rank p=0.09) and OS (HR=1.6, log rank p=0.14) in adjuvantly treated ACC patients did not differ significantly between tumours with high and low SOAT1 expression. Similarly in the palliative setting, OS (HR=1.0, p=0.47) and PFS (HR=0.6, p=0.66) were not different. In line, high SOAT1 expression did not predict if patients reach the therapeutic window of mitotane. Conclusion: SOAT1 expression alone was not correlated with clinically significantly RFS, PFS, and OS in ACC patients neither in the adjuvant nor in the palliative setting.

Alterations in Protein Kinase A Substrate Specificity as a Potential Cause of Cushing Syndrome

Cushing syndrome is a severe endocrine disorder of cortisol excess associated with major metabolic and cardiovascular sequelae. We recently identified somatic mutations in PRKACA, the gene encoding the catalytic (C) α subunit of protein kinase A (PKA), as being responsible for cortisol-producing adrenocortical adenomas (CPAs), which are a major cause of Cushing syndrome. In spite of previous studies on the two initially identified mutations (L206R, 199_200insW), the mechanisms of action of the clinically highly relevant PRKACA mutations remain poorly understood. Here, by investigating a large panel of PRKACA mutations, including all those identified so far in Cushing syndrome, we unexpectedly found that not all mutations interfere with the binding of regulatory (R) subunits as previously hypothesized. Because several mutations lie in a region of PKA Cα involved in substrate recognition, we investigated their consequences on substrate specificity by quantitative phosphoproteomics. We found that all three mutations analyzed (L206R, 200_201insV, and d244-248+E249Q) cause major changes in the preference of PKA for its targets, leading to hyperphosphorylation of several PKA substrates, most notably including histone H1.4 at Ser36, which is required for and promotes mitosis. This is reflected by a ninefold hyperphosphorylation of H1.4 in CPAs carrying the L206R mutation. Thus, our findings suggest that in addition to hampering binding to R subunits, PRKACA mutations act by altering PKA substrate specificity. These findings shed light on the molecular events leading to Cushing syndrome and illustrate how mutations altering substrate specificity of a protein kinase may cause human disease.

Hsp90 inhibition in adrenocortical carcinoma: Limited drug synergism with mitotane

90 kDa heat shock proteins (Hsp90) act as protein chaperones and play a role in modulating endoplasmic reticulum (ER) stress. Hsp90 inhibitors are under clinical investigation as cancer treatment. Mitotane therapy of adrenocortical carcinoma (ACC) has been shown to act through lipid-induced ER-stress. To explore the potential of Hsp90 inhibitors in ACC as a single agent and in combination with mitotane, we analyzed two independent gene expression data sets of adrenal tumors in silico and treated the ACC cell line model NCI-H295 with Hsp90 inhibitors BIIB021 (B) and CCT18159 (C) alone and in combination with mitotane. ER-stress markers were monitored by immunoblotting. Drug synergism was quantified using the median effect model with cell viability as read-out. Cytosolic Hsp90 isoforms AA1 and AB1 were significantly overexpressed in ACC. Viability of H295 cells was impaired by B and C as single agents with an EC₅₀ of 5.7 × 10^-6M and 12.1 × 10^-6M. B but not C dose-dependently increased XBP1 splicing and CHOP expression indicative of ER-stress activation. ER-stress marker expression was enhanced by co-incubation of B with 10  μM but not 5  μM mitotane. Maximal CHOP expression was induced by 25 μM mitotane alone with no additional effect of B. Combination indices (CI) of B and C with mitotane ranged from 0.64 to 1.38 and 0.68 to 1.30, respectively where CI values < 0.5 support clinically-relevant drug synergism. In conclusion, Hsp90 paralogs are differentially expressed in ACC and B but not C activates ER-stress in ACC cells. No meaningful drug synergism of Hsp90 inhibitors with mitotane was observed.

Targeted Molecular Analysis in Adrenocortical Carcinomas: A Strategy Toward Improved Personalized Prognostication

CONTEXT

Adrenocortical carcinoma (ACC) has a heterogeneous prognosis, and current medical therapies have limited efficacy in its advanced stages. Genome-wide multiomics studies identified molecular patterns associated with clinical outcome.

OBJECTIVE

Here, we aimed at identifying a molecular signature useful for both personalized prognostic stratification and druggable targets, using methods applicable in clinical routine.

DESIGN

In total, 117 tumor samples from 107 patients with ACC were analyzed. Targeted next-generation sequencing of 160 genes and pyrosequencing of 4 genes were applied to formalin-fixed, paraffin-embedded (FFPE) specimens to detect point mutations, copy number alterations, and promoter region methylation. Molecular results were combined with clinical/histopathological parameters (tumor stage, age, symptoms, resection status, and Ki-67) to predict progression-free survival (PFS).

RESULTS

In addition to known driver mutations, we detected recurrent alterations in genes not previously associated with ACC (e.g., NOTCH1, CIC, KDM6A, BRCA1, BRCA2). Best prediction of PFS was obtained integrating molecular results (more than one somatic mutation, alterations in Wnt/β-catenin and p53 pathways, high methylation pattern) and clinical/histopathological parameters into a combined score (P < 0.0001, χ2 = 68.6). Accuracy of prediction for early disease progress was 83.3% (area under the receiver operating characteristic curve: 0.872, 95% confidence interval 0.80 to 0.94). Furthermore, 17 potentially targetable alterations were found in 64 patients (e.g., in CDK4, NOTCH1, NF1, MDM2, and EGFR and in DNA repair system).

CONCLUSIONS

This study demonstrates that molecular profiling of FFPE tumor samples improves prognostication of ACC beyond clinical/histopathological parameters and identifies new potential drug targets. These findings pave the way to precision medicine in this rare disease.

High-Resolution Tissue Mass Spectrometry Imaging Reveals a Refined Functional Anatomy of the Human Adult Adrenal Gland

In the adrenal gland, neuroendocrine cells that synthesize catecholamines and epithelial cells that produce steroid hormones are united beneath a common organ capsule to function as a single stress-responsive organ. The functional anatomy of the steroid hormone-producing adrenal cortex and the catecholamine-producing medulla is ill defined at the level of small molecules. Here, we report a comprehensive high-resolution mass spectrometry imaging (MSI) map of the normal human adrenal gland. A large variety of biomolecules was accessible by matrix-assisted laser desorption/ionization-Fourier transform-ion cyclotron resonance MSI, including nucleoside phosphates indicative of oxidative phosphorylation, sterol and steroid metabolites, intermediates of glycolysis and the tricarboxylic acid cycle, lipids, and fatty acids. Statistical clustering analyses yielded a molecularly defined adrenal anatomy of 10 distinct molecular zones including a highly structured corticomedullary interface. By incorporating pathway information, activities of carbohydrate, amino acid, and lipid metabolism as well as endocrine bioactivity were revealed to be highly spatially organized, which could be visualized as different molecularly defined zones. Together, these findings provide a molecular definition of human adult adrenal gland structure beyond classical histological anatomy.

Livin/BIRC7 expression as malignancy marker in adrenocortical tumors

Livin/BIRC7 is a member of the inhibitors of apoptosis proteins family, which are involved in tumor development through the inhibition of caspases. Aim was to investigate the expression of livin and other members of its pathway in adrenocortical tumors and in the adrenocortical carcinoma (ACC) cell line NCI-H295R.

The mRNA expression of livin, its isoforms α and β, XIAP, CASP3 and DIABLO was evaluated by qRT-PCR in 82 fresh-frozen adrenal tissues (34 ACC, 25 adenomas = ACA, 23 normal adrenal glands = NAG). Livin protein expression was assessed by immunohistochemistry in 270 paraffin-embedded tissues (192 ACC, 58 ACA, 20 NAG). Livin, CASP3 and cleaved caspase-3 were evaluated in NCI-H295R after induction of livin overexpression.

Relative livin mRNA expression was significantly higher in ACC than in ACA and NAG (0.060 ± 0.116 vs 0.004 ± 0.014 and 0.002 ± 0.009, respectively, p < 0.01), being consistently higher in tumors than in adjacent NAG and isoform β more expressed than α. No significant differences in CASP3, XIAP and DIABLO levels were found among these groups. In immunohistochemistry, livin was localized in both cytoplasm and nuclei. The ratio between cytoplasmic and nuclear staining was significantly higher in ACC (1.51 ± 0.66) than in ACA (0.80 ± 0.35) and NAG (0.88 ± 0.27; p < 0.0001). No significant correlations were observed between livin expression and histopathological parameters or clinical outcome. In NCI-H295R cells, the livin overexpression slightly reduced the activation of CASP3, but did not correlate with cell viability.

In conclusion, livin is specifically over-expressed in ACC, suggesting that it might be involved in adrenocortical tumorigenesis and represent a new molecular marker of malignancy.

ERCC1 as predictive biomarker to platinum-based chemotherapy in adrenocortical carcinomas

OBJECTIVE

Platinum-based chemotherapy (PBC) is the most effective cytotoxic treatment for advanced adrenocortical carcinoma (ACC). Excision repair cross complementing group 1 (ERCC1) plays a critical role in the repair of platinum-induced DNA damage. Two studies investigating the role of ERCC1 immunostaining as a predictive marker for the response to PBC in ACC had reported conflicting results. Both studies used the ERCC1-antibody clone 8F1 that later turned out to be not specific. The aim of this study was to evaluate the predictive role of ERCC1 with a new specific antibody in a larger series of ACC.

DESIGN AND METHODS

146 ACC patients with available FFPE slides were investigated. All patients underwent PBC (median cycles = 6), including cisplatin (n = 131) or carboplatin (n = 15), in most cases combined with etoposide (n = 144), doxorubicin (n = 131) and mitotane (n = 131). Immunostaining was performed with the novel ERCC1-antibody clone 4F9. The relationship between ERCC1 expression and clinicopathological parameters, as well as best objective response to therapy and progression-free survival (PFS) during PBC was evaluated.

RESULTS

High ERCC1 expression was observed in 66% of ACC samples. During PBC, 43 patients experienced objective response (29.5%), 49 stable disease (33.6%), 8 mixed response (5.5%) and 46 progressive disease (31.5%) without any relationship with the ERCC1 immunostaining. No significant correlation was also found between ERCC1 expression and progression-free survival (median 6.5 vs 6 months, P  =  0.33, HR = 1.23, 95% CI = 0.82-2.0).

CONCLUSION

ERCC1 expression is not directly associated with sensitivity to PBC in ACC. Thus, other predictive biomarkers are required to support treatment decisions in patients with ACC.

Gemcitabine-Based Chemotherapy in Adrenocortical Carcinoma: A Multicenter Study of Efficacy and Predictive Factors

CONTEXT

Adrenocortical carcinoma (ACC) is rare and confers an unfavorable prognosis in advanced stages. Other than combination chemotherapy with cisplatin, etoposide, doxorubicin, and mitotane, the second- and third-line regimens are not well-established. Gemcitabine (GEM)-based chemotherapy was suggested in a phase 2 clinical trial with 28 patients. In other solid tumors, human equilibrative nucleoside transporter type 1 (hENT1) and/or ribonucleotide reductase catalytic subunit M1 (RRM1) expression have been associated with resistance to GEM.

OBJECTIVE

To assess the efficacy of GEM-based chemotherapy in ACC in a real-world setting and the predictive role of molecular parameters.

DESIGN

Retrospective multicenter study.

SETTING

Referral centers of university hospitals.

PATIENTS AND MATERIALS

A total of 145 patients with advanced ACC were treated with GEM-based chemotherapy (132 with concomitant capecitabine). Formalin-fixed paraffin-embedded tumor material was available for 70 patients for immunohistochemistry.

OUTCOME MEASURES

The main outcome measures were progression-free survival (PFS) and an objective response to GEM-based chemotherapy. The secondary objective was the predictive role of hENT1 and RRM1.

RESULTS

The median PFS for the patient population was 12 weeks (range, 1 to 94). A partial response or stable disease was achieved in 4.9% and 25.0% of cases, with a median duration of 26.8 weeks. Treatment was generally well tolerated, with adverse events of grade 3 or 4 occurring in 11.0% of cases. No substantial effect of hENT1 and/or RRM1 expression was observed in response to GEM-based chemotherapy.

CONCLUSIONS

GEM-based chemotherapy is a well-tolerated, but modestly active, regimen against advanced ACC. No reliable molecular predictive factors could be identified. Owing to the scarce alternative therapeutic options, GEM-based chemotherapy remains an important option for salvage treatment for advanced ACC.

Assessment of VAV2 Expression Refines Prognostic Prediction in Adrenocortical Carcinoma

CONTEXT

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with overall poor prognosis. The Ki67 labeling index (LI) has a major prognostic role in localized ACC after complete resection, but its estimates may suffer from considerable intra- and interobserver variability. VAV2 overexpression induced by increased Steroidogenic Factor-1 dosage is an essential factor driving ACC tumor cell invasion.

OBJECTIVE

To assess the prognostic role of VAV2 expression in ACC by investigation of a large cohort of patients.

DESIGN, SETTING, AND PARTICIPANTS

A total of 171 ACC cases (157 primary tumors, six local recurrences, eight metastases) from seven European Network for the Study of Adrenal Tumors centers were studied.

OUTCOME MEASUREMENTS

H-scores were generated to quantify VAV2 expression. VAV2 expression was divided into two categories: low (H-score, <2) and high (H-score, ≥2). The Ki67 LI retrieved from patients' pathology records was also categorized into low (<20%) and high (≥20%). Clinical and immunohistochemical markers were correlated with progression-free survival (PFS) and overall survival (OS).

RESULTS

VAV2 expression and Ki67 LI were significantly correlated with each other and with PFS and OS. Heterogeneity of VAV2 expression inside the same tumor was very low. Combined assessment of VAV2 expression and Ki67 LI improved patient stratification to low-risk and high-risk groups.

CONCLUSION

Combined assessment of Ki67 LI and VAV2 expression improves prognostic prediction in ACC.

Topoisomerase 2α and thymidylate synthase expression in adrenocortical cancer

Topoisomerase II alpha (TOP2A) and thymidylate synthase (TS) are known prognostic parameters in several tumors and also predictors of efficacy of anthracyclines, topoisomerase inhibitors and fluoropirimidines, respectively. Expression of TOP2A and TS mRNA was assessed in 98 patients with adrenocortical carcinoma (ACC) and protein expression was assessed by immunohistochemistry in a subset of 39 tumors. Ninety-two patients were radically resected for stage II-III disease and 38 of them received adjuvant mitotane. Twenty-six patients with metastatic disease received the EDP-M (etoposide, doxorubicin, Adriamycin, cisplatin plus mitotane). TOP2A and TS expression in ACC tissue was directly correlated with the clinical data. Both markers were not associated with either disease free survival (DFS) or overall survival (OS) in multivariate analyses and failed to be associated to mitotane efficacy. Disease response or stabilization to EDP-M treatment was observed in 12/17 (71%) and 1/9 (11%) patients with high and low TOP2A expressing tumors (P = 0.0039) and 9/13 (69%) and 4/13 (31%) patients with high and low TS expressing ACC, respectively (P = 0.049). High TOP2A expression was significantly associated with longer time to progression (TTP) after EDP-M. TOP2A and TS proteins assessed by immunohistochemistry significantly correlated with mRNA expression. Immunohistochemical TOP2A expression was associated with a non-significant better response and longer TTP after EDP-M. TOP2A and TS were neither prognostic nor predictive of mitotane efficacy in ACC patients. The predictive role of TOP2A expression of EDP-M activity suggests a significant contribution of Adriamycin and etoposide for the efficacy of the EDP scheme.

Differential expression of the protein kinase A subunits in normal adrenal glands and adrenocortical adenomas

Somatic mutations in protein kinase A catalytic α subunit (PRKACA) were found to be causative for 30-40% of cortisol-producing adenomas (CPA) of the adrenal gland, rendering PKA signalling constitutively active. In its resting state, PKA is a stable and inactive heterotetramer, consisting of two catalytic and two regulatory subunits with the latter inhibiting PKA activity. The human genome encodes three different PKA catalytic subunits and four different regulatory subunits that are preferentially expressed in different organs. In normal adrenal glands all regulatory subunits are expressed, while CPA exhibit reduced protein levels of the regulatory subunit IIβ. In this study, we linked for the first time the loss of RIIβ protein levels to the PRKACA mutation status and found the down-regulation of RIIβ to arise post-transcriptionally. We further found the PKA subunit expression pattern of different tumours is also present in the zones of the normal adrenal cortex and demonstrate that the different PKA subunits have a differential expression pattern in each zone of the normal adrenal gland, indicating potential specific roles of these subunits in the regulation of different hormones secretion.

Dosage-dependent regulation of VAV2 expression by steroidogenic factor-1 drives adrenocortical carcinoma cell invasion

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with a dismal prognosis. Genomic studies have enabled progress in our understanding of the molecular bases of ACC, but factors that influence its prognosis are lacking. Amplification of the gene encoding the transcription factor steroidogenic factor-1 (SF-1; also known as NR5A1) is one of the genetic alterations common in ACC. We identified a transcriptional regulatory mechanism involving increased abundance of VAV2, a guanine nucleotide exchange factor for small GTPases that control the cytoskeleton, driven by increased expression of the gene encoding SF-1 in ACC. Manipulating SF-1 and VAV2 abundance in cultured ACC cells revealed that VAV2 was a critical factor for SF-1-induced cytoskeletal remodeling and invasion in culture (Matrigel) and in vivo (chicken chorioallantoic membrane) models. Analysis of ACC patient cohorts indicated that greater VAV2 abundance robustly correlated with poor prognosis in ACC patients. Because VAV2 is a druggable target, our findings suggest that blocking VAV2 may be a new therapeutic approach to inhibit metastatic progression in ACC patients.

DNA Methylation Is an Independent Prognostic Marker of Survival in Adrenocortical Cancer

CONTEXT

Adrenocortical cancer (ACC) is an aggressive tumor with a heterogeneous outcome. Prognostic stratification is difficult even based on tumor stage and Ki67. Recently integrated genomics studies have demonstrated that CpG islands hypermethylation is correlated with poor survival.

OBJECTIVE

The goal of this study was to confirm the prognostic value of CpG islands methylation on an independent cohort.

DESIGN

Methylation was measured by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA).

SETTING

MS-MLPA was performed in a training cohort of 50 patients with ACC to identify the best set of probes correlating with disease-free survival (DFS) and overall survival (OS). These outcomes were validated in an independent cohort from 21 ENSAT centers.

PATIENTS

The validation cohort included 203 patients (64% women, median age 50 years, 80% localized tumors).

MAIN OUTCOME MEASURES

DFS and OS.

RESULTS

In the training cohort, mean methylation of 4 genes (PAX5, GSTP1, PYCARD, PAX6) was the strongest methylation marker. In the validation cohort, methylation was a significant prognostic factor of DFS (P < 0.0001) and OS (P < 0.0001). Methylation, Ki67, and ENSAT stage were combined in multivariate models. For DFS, methylation (P = 0.0005) and stage (P < 0.0001) but not Ki67 (P = 0.19) remained highly significant. For OS, methylation (P = 0.0006), stage (P < 0.0001), and Ki67 (P = 0.024) were independent prognostic factors.

CONCLUSIONS

Tumor DNA methylation emerges as an independent prognostic factor in ACC. MS-MLPA is readily compatible with clinical routine and should enhance our ability for prognostication and precision medicine.