The molecular basis of adrenocortical cancer

The Role of Fascin-1 in Human Urologic Cancers: A Promising Biomarker or Therapeutic Target?

Human cancer statistics show that an increased incidence of urologic cancers such as bladder cancer, prostate cancer, and renal cell carcinoma. Due to the lack of early markers and effective therapeutic targets, their prognosis is poor. Fascin-1 is an actin-binding protein, which functions in the formation of cell protrusions by cross-linking with actin filaments. Studies have found that fascin-1 expression is elevated in most human cancers and is related to outcomes such as neoplasm metastasis, reduced survival, and increased aggressiveness. Fascin-1 has been considered as a potential therapeutic target for urologic cancers, but there is no comprehensive review to evaluate these studies. This review aimed to provide an enhanced literature review, outline, and summarize the mechanism of fascin-1 in urologic cancers and discuss the therapeutic potential of fascin-1 and the possibility of its use as a potential marker. We also focused on the correlation between the overexpression of fascin-1 and clinicopathological parameters. Mechanistically, fascin-1 is regulated by several regulators and signaling pathways (such as long noncoding RNA, microRNA, c-Jun N-terminal kinase, and extracellular regulated protein kinases). The overexpression of fascin-1 is related to clinicopathologic parameters such as pathological stage, bone or lymph node metastasis, and reduced disease-free survival. Several fascin-1 inhibitors (G2, NP-G2-044) have been evaluated in vitro and in preclinical models. The study proved the promising potential of fascin-1 as a newly developing biomarker and a potential therapeutic target that needs further investigation. The data also highlight the inadequacy of fascin-1 to serve as a novel biomarker for prostate cancer.

Molecular Cluster Mining of Adrenocortical Carcinoma via Multi-Omics Data Analysis Aids Precise Clinical Therapy

Adrenocortical carcinoma (ACC) is a malignancy of the endocrine system. We collected clinical and pathological features, genomic mutations, DNA methylation profiles, and mRNA, lncRNA, microRNA, and somatic mutations in ACC patients from the TCGA, GSE19750, GSE33371, and GSE49278 cohorts. Based on the MOVICS algorithm, the patients were divided into ACC1-3 subtypes by comprehensive multi-omics data analysis. We found that immune-related pathways were more activated, and drug metabolism pathways were enriched in ACC1 subtype patients. Furthermore, ACC1 patients were sensitive to PD-1 immunotherapy and had the lowest sensitivity to chemotherapeutic drugs. Patients with the ACC2 subtype had the worst survival prognosis and the highest tumor-mutation rate. Meanwhile, cell-cycle-related pathways, amino-acid-synthesis pathways, and immunosuppressive cells were enriched in ACC2 patients. Steroid and cholesterol biosynthetic pathways were enriched in patients with the ACC3 subtype. DNA-repair-related pathways were enriched in subtypes ACC2 and ACC3. The sensitivity of the ACC2 subtype to cisplatin, doxorubicin, gemcitabine, and etoposide was better than that of the other two subtypes. For 5-fluorouracil, there was no significant difference in sensitivity to paclitaxel between the three groups. A comprehensive analysis of multi-omics data will provide new clues for the prognosis and treatment of patients with ACC.

Ang-Tie Angiogenic Pathway Is Distinctively Expressed in Benign and Malignant Adrenocortical Tumors

The differential diagnosis between adrenocortical adenomas (ACAs) and adrenocortical carcinomas (ACCs) relies on unspecific clinical, imaging and histological features, and, so far, no single molecular biomarker has proved to improve diagnostic accuracy. Similarly, prognostic factors have an insufficient capacity to predict the heterogeneity of ACC clinical outcomes, which consequently lead to inadequate treatment strategies. Angiogenesis is a biological process regulated by multiple signaling pathways, including VEGF and the Ang–Tie pathway. Many studies have stressed the importance of angiogenesis in cancer development and metastasis. In the present study, we evaluated the expression of VEGF and Ang–Tie pathway mediators in adrenocortical tumors (ACTs), with the ultimate goal of assessing whether these molecules could be useful biomarkers to improve diagnostic accuracy and/or prognosis prediction in ACC. The expression of the proteins involved in angiogenesis, namely CD34, VEGF, VEGF-R2, Ang1, Ang2, Tie1 and Tie2, was assessed by immunohistochemistry in ACC (n = 22), ACA with Cushing syndrome (n = 8) and non-functioning ACA (n = 13). ACC presented a significantly higher Ang1 and Ang2 expression when compared to ACA. Tie1 expression was higher in ACC with venous invasion and in patients with shorter overall survival. In conclusion, although none of these biomarkers showed to be useful for ACT diagnosis, the Ang–Tie pathway is active in ACT and may play a role in regulating ACT angiogenesis.

Clinical Outcomes of Children With Adrenocortical Carcinoma in the Context of Germline TP53 Status

Adrenocortical carcinoma (ACC) is a rare, aggressive malignancy of the adrenal cortex. This study characterizes a single-institution cohort of children treated for ACC, and explores the relationship between clinical outcomes of ACC and germline TP53 mutation status. We performed a retrospective chart review of 23 consecutive pediatric patients with ACC treated at The Hospital for Sick Children, Toronto, Canada, between 1977 and 2017. Clinical, biochemical, radiologic, pathologic, and genetic data were collected for each patient. ACC diagnosis followed a bimodal age distribution of 0 to 6 (n=17) and 12+ (n=6) years, with a female:male ratio of 3.6:1. Ten of 20 patients tested for germline TP53 status carried a pathogenic (9) or likely pathogenic (1) variant, including all but 1 male patient. Only 3 patients died of ACC-related causes, each 5 months post-diagnosis. When treated with resection and combination chemotherapy, carriers of germline TP53 mutations may respond more favorably than their wild-type counterparts. In addition, the survival of patients reported in our cohort with high-stage ACC was appreciably greater than previously described (100.0% for stage II, 50.0% for stage III, and 42.9% for stage IV), favoring aggressive intervention in these patient populations.

Emerging drugs for the treatment of adrenocortical carcinoma

Introduction: Adrenocortical cancer (ACC) is a rare and aggressive disease with a median survival of 14-17 months and 5-year survival of around 20% for advanced disease. Emerging evidence of sub-groups of ACC with specific molecular drivers indicate ACC may be amenable to inhibition of receptor tyrosine kinases involved in growth and angiogenic signaling. A significant subset of patients may also be responsive to immune strategies.Areas covered: This review outlines approaches of targeting upregulated growth pathways including Insulin-like Growth Factor, Vascular Endothelial Growth Factor, Fibroblast Growth Factor and Epidermal Growth Factor Receptor in ACC. Data of immune checkpoint blockade with nivolumab, ipilimumab, pembrolizumab and avelumab is explored in detail. Genomic studies indicate that up to 40% of ACC are driven by dysregulated WNT and glucocorticoid signaling, special focus is placed on emerging drugs in these pathways.Expert opinion: Progress in the treatment of ACC has faced challenges stemming from the rarity of the disease. Given recent advances in the understanding of the molecular pathogenesis of ACC, a window of opportunity has now opened to make significant progress in developing therapeutic options that target key pathways such as excessive glucocorticoid signaling, WNT signaling, cell cycle and immune checkpoints.

The Potential of Steroid Profiling by Mass Spectrometry in the Management of Adrenocortical Carcinoma

Radiological and endocrinological work up of adrenal neoplasms is aimed at distinguishing between frequent non-functioning adenomas and rare but very aggressive adrenocortical carcinoma (ACC). Relevant research has addressed the identification of molecular, genetic and hormonal markers that could have clinical significance for malignancy, as well as a prognostic value. Regarding endocrine aspects, attention has been paid to the pattern of steroid secretion that can be affected by altered steroidogenic pathway in ACC. The advent of mass spectrometry techniques has overcome many limitations usually associated with immunoassays, allowing the determination of both common and rarely measured steroids in a single analysis with high specificity and sensitivity. Indeed, mass spectrometry strategies may be able to identify an individualized steroid profile of ACC, allowing a rapid diagnosis and a specific follow-up. In this review, insights, strengths and limitations of mass spectrometry-based approaches in steroid profiling, as well as of immunoassay in steroid measurements, will be specifically discussed. Moreover, the latest findings on steroid profiling by mass spectrometry-based techniques, the most promising analytical tool, will be summarized to evaluate if steroid profiling might be the clue for solving the clinical dilemma in differentiating ACC from non-functioning adrenocortical adenomas (ACA).

The effects of mitotane and 1α,25-dihydroxyvitamin D3 on Wnt/beta-catenin signaling in human adrenocortical carcinoma cells

PURPOSE

Mitotane is the only chemotherapeutic agent available for the treatment of adrenocortical carcinoma (ACC), however, the anti-neoplastic efficacy is limited due to several side-effects in vivo. There is, therefore, a need of exploring for new anti-tumoral agents which can be used either alone or in combination with mitotane. The active vitamin D metabolite 1α,25-dihydroxyvitamin D₃ (1α,25(OH)₂D₃) acts as an anti-proliferative agent in human cancer by inhibiting the Wnt/beta-catenin pathway through the vitamin D receptor (VDR). The aim of this study was to study the effects of mitotane and 1α,25(OH)₂D₃, individually or in combination, in an in vitro model with H295R ACC cells, and to elucidate the molecular events behind their effects involving the Wnt/beta-catenin signaling.

METHODS AND RESULTS

Multiple concentrations of mitotane and 1α,25(OH)₂D₃, individually or in combination, were tested on H295R cells for 24-96 h, and the effects analysed by MTT. A reduction in cell growth was observed in a dose/time-dependent manner for both mitotane and 1α,25(OH)₂D₃. In addition, a combination of clinically sub-therapeutic concentrations of mitotane with 1α,25(OH)₂D₃, had an additive anti-proliferative effect (Combination Index = 1.02). In a wound healing assay, individual treatments of both mitotane and 1α,25(OH)₂D₃ reduced the migration ability of H295R cells, with the effect further enhanced on combining both the agents. Western blotting and qRT-PCR analysis showed a modulation of the Wnt/beta-catenin and VDR signaling pathways.

CONCLUSION

Our results show an additive effect of mitotane and 1α,25(OH)₂D₃ on the inhibition of H295R ACC cell growth and viability, and suggest that molecular mechanisms of their effects involve a functional link between VDR and Wnt/beta-catenin pathways.

IGF2 role in adrenocortical carcinoma biology

PURPOSE

Clinical outcomes of adrenocortical carcinomas (ACC) could be improved by using novel treatment targets based on the recent advances of tumor biology knowledge. Insulin-like growth factor 2 (IGF2) protein expression is usually 8-80 fold higher in ACC when compared to normal adrenal glands (N-AG) or adrenocortical adenomas (ACA), despite the fact that the biological features of high vs. low IGF2 expressing ACC have not yet been well characterized. Our goal was to understand the IGF2 role in ACC biology by focusing in several cancer hallmarks, including cell proliferation, viability, invasion, and metabolism.

METHODS

IGF2 immunohistochemistry expression was evaluated in ACC (n = 13), non-functioning adrenocortical adenoma (ACAn) (n = 14), and N-AG (n = 9). The effects of IGF2 (50, 100 ng/mL) in cell proliferation, viability, invasion, and metabolism, as well as in MAPK/ERK and mTOR pathways activation and N-cadherin expression, were evaluated in the ACC human cell line H295R.

RESULTS

IGF2 expression was increased in ACC compared to ACAn and N-AG. Exposure to 100 ng/mL of IGF2 increased H295R cell proliferation and viability. mTOR inhibition reverted IGF2 triggered cell proliferation and viability while MEK/MAPK/ERK inhibition only reverted IGF2 effects on cell proliferation. IGF2 at a 50 ng/mL concentration increased the glycolytic flux and decreased glutamine consumption.

CONCLUSIONS

IGF2 is an excellent marker to differentiate ACC from ACAn. In addition, IGF2 was demonstrated to influence adrenocortical cancer cell proliferation, metabolism, and viability, but not the cell invasion. These data support that different IGF2 concentrations in ACC can be responsible for different biological behaviors of ACC.

Management of Adrenocortical Carcinoma

PURPOSE OF REVIEW

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy typically with poor prognosis. This review aims to summarize the current knowledge regarding the clinical management of ACC.

RECENT FINDINGS

Surgery remains the cornerstone for localized ACC management. In more advanced cases, debulking surgery when feasible can help with hormonal control and may allow the initiation of systemic therapy. Over the last few years, our understanding of ACC molecular pathogenesis has expanded with no significant change in treatment options. Platinum-based chemotherapy is the gold standard in metastatic ACC despite suboptimal efficacy. Tyrosine kinase inhibitor use did not result in meaningful benefit in ACC patients. Multiple clinical trials are currently exploring the role of immunotherapy in ACC. Despite the remarkable improvement in our understanding of the molecular signature and pathways in ACC, this knowledge did not yield a major breakthrough in management of advanced ACC. Multi-institutional and international collaborations are needed to identify promising treatments and new therapeutic targets to improve the care of ACC patients.

A novel FOXO1-mediated dedifferentiation blocking role for DKK3 in adrenocortical carcinogenesis

Background

Dysregulated WNT signaling dominates adrenocortical malignancies. This study investigates whether silencing of the WNT negative regulator DKK3 (Dickkopf-related protein 3), an implicated adrenocortical differentiation marker and an established tumor suppressor in multiple cancers, allows dedifferentiation of the adrenal cortex.

Methods

We analyzed the expression and regulation of DKK3 in human adrenocortical carcinoma (ACC) by qRT-PCR, immunofluorescence, promoter methylation assay, and copy number analysis. We also conducted functional studies on ACC cell lines, NCI-H295R and SW-13, using siRNAs and enforced DKK3 expression to test DKK3’s role in blocking dedifferentiation of adrenal cortex.

Results

While robust expression was observed in normal adrenal cortex, DKK3 was down-regulated in the majority (>75%) of adrenocortical carcinomas (ACC) tested. Both genetic (gene copy loss) and epigenetic (promoter methylation) events were found to play significant roles in DKK3 down-regulation in ACCs. While NCI-H295R cells harboring β-catenin activating mutations failed to respond to DKK3 silencing, SW-13 cells showed increased motility and reduced clonal growth. Conversely, exogenously added DKK3 also increased motility of SW-13 cells without influencing their growth. Enforced over-expression of DKK3 in SW-13 cells resulted in slower cell growth by an extension of G1 phase, promoted survival of microcolonies, and resulted in significant impairment of migratory and invasive behaviors, largely attributable to modified cell adhesions and adhesion kinetics. DKK3-over-expressing cells also showed increased expression of Forkhead Box Protein O1 (FOXO1) transcription factor, RNAi silencing of which partially restored the migratory proficiency of cells without interfering with their viability.

Conclusions

DKK3 suppression observed in ACCs and the effects of manipulation of DKK3 expression in ACC cell lines suggest a FOXO1-mediated differentiation-promoting role for DKK3 in the adrenal cortex, silencing of which may allow adrenocortical dedifferentiation and malignancy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3152-5) contains supplementary material, which is available to authorized users.

Suppression of cytochrome P450 4B1: An early event in adrenocortical tumorigenesis

BACKGROUND

Adrenocortical carcinoma is a rare neoplasm with a poor prognosis. Conversely, adrenocortical adenomas are common and benign. Despite their shared histologic origin, little evidence exists to suggest that adrenocortical adenoma arises from adrenocortical carcinoma. Recent genetic analyses of adrenocortical carcinoma have shown recurrent gene copy deletion of CYP4B1, a cytochrome P450 isozyme. This study investigates a potential role for CYP4B1 in modulating adrenocortical tumorigenesis and/or conferring chemoresistance to adrenocortical carcinomas.

METHODS

Using TaqMan, real-time quantitative polymerase chain reaction techniques, we investigated CYP4B1 expression in normal adrenal cortex (n = 10), histologically confirmed adrenocortical adenomas (n = 10), and adrenocortical carcinomas (n = 10). Adrenocortical carcinoma cell lines were enforced to express CYP4B1, and effects on cell death and enhanced mitotane and cisplatin sensitivity were tested.

RESULTS

Gene expression analyses demonstrated suppression of CYP4B1 in 100% of both the adrenocortical adenomas (10/10) and adrenocortical carcinomas (10/10) tested. Average relative expression of CYP4B1 was decreased at 0.19 (0.01-0.50; P < .01) in adrenocortical adenomas and nearly absent in adrenocortical carcinomas (0.01; 0.00-0.05; P < .01). Protein expression correlated with mRNA expression. Ectopic expression of CYP4B1 promoted cytotoxicity and increased chemosensitivity in adrenocortical carcinoma cell lines.

CONCLUSION

CYP4B1 is silenced in both benign and malignant adrenocortical tumors and may contribute to tumorigenesis and chemoresistance. Sensitization of adrenocortical carcinoma cells engineered to overexpress CYP4B1 further supports this notion.

Proteome analysis of adrenal cortical tumors

INTRODUCTION

Adrenal tumor is a relatively common tumor. The discrimination between adrenal cortical adenoma (ACA) and adrenal cortical carcinoma (ACC) is crucial as these two diseases have distinct prognosis. ACA is a benign tumor curable by surgical excision, while the prognosis of ACC is extremely poor, with a 5-year mortality of 75-90%. Therefore, previous proteomic studies focused on markers allowing the differentiation between ACA and ACC.

AREAS COVERED

Several proteomic approaches based on the analysis of various samples such as human tissues, urine, and cell lines. In this review, we focused on proteomic studies performed to improve adrenal tumor diagnosis and identify ACC therapeutic targets. Expert commentary: The rapid development of cancer genomics provided a lot of information, which affects functional proteomics. In practice, differentially expressed proteins between ACA and ACC have been suggested in several proteomic studies and had a biologic implication in ACC.

2D-DIGE proteomic analysis identifies new potential therapeutic targets for adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare aggressive tumor with poor prognosis when metastatic at diagnosis. The tumor biology is still mostly unclear, justifying the limited specificity and efficacy of the anti-cancer drugs currently available. This study reports the first proteomic analysis of ACC by using two-dimensional-differential-in-gel-electrophoresis (2D-DIGE) to evaluate a differential protein expression profile between adrenocortical carcinoma and normal adrenal. Mass spectrometry, associated with 2D-DIGE analysis of carcinomas and normal adrenals, identified 22 proteins in 27 differentially expressed 2D spots, mostly overexpressed in ACC. Gene ontology analysis revealed that most of the proteins concurs towards a metabolic shift, called the Warburg effect, in adrenocortical cancer. The differential expression was validated by Western blot for Aldehyde-dehydrogenase-6-A1,Transferrin, Fascin-1,Lamin A/C,Adenylate-cyclase-associated-protein-1 and Ferredoxin-reductase. Moreover, immunohistochemistry performed on paraffin-embedded ACC and normal adrenal specimens confirmed marked positive staining for all 6 proteins diffusely expressed by neoplastic cells, compared with normal adrenal cortex.

In conclusion, our preliminary findings reveal a different proteomic profile in adrenocortical carcinoma compared with normal adrenal cortex characterized by overexpression of mainly metabolic enzymes, thus suggesting the Warburg effect also occurs in ACC. These proteins may represent promising novel ACC biomarkers and potential therapeutic targets if validated in larger cohorts of patients.

Epigenetic alterations in endocrine-related cancer

Aberrant epigenetics is a hallmark of cancer, and endocrine-related tumors are no exception. Recent research has been identifying an ever-growing number of epigenetic alterations in both genomic DNA methylation and histone post-translational modification in tumors of the endocrine system. Novel microarray and ultra-deep sequencing technologies have allowed the identification of genome-wide epigenetic patterns in some tumor types such as adrenocortical, parathyroid, and breast carcinomas. However, in other cancer types, such as the multiple endocrine neoplasia syndromes and thyroid cancer, tumor information is limited to candidate genes alone. Future research should fill this gap and deepen our understanding of the functional role of these alterations in cancer, as well as defining their possible clinical uses.

Next-generation sequencing of adrenocortical carcinoma reveals new routes to targeted therapies

Aims

Adrenocortical carcinoma (ACC) carries a poor prognosis and current systemic cytotoxic therapies result in only modest improvement in overall survival. In this retrospective study, we performed a comprehensive genomic profiling of 29 consecutive ACC samples to identify potential targets of therapy not currently searched for in routine clinical practice.

Methods

DNA from 29 ACC was sequenced to high, uniform coverage (Illumina HiSeq) and analysed for genomic alterations (GAs).

Results

At least one GA was found in 22 (76%) ACC (mean 2.6 alterations per ACC). The most frequent GAs were in TP53 (34%), NF1 (14%), CDKN2A (14%), MEN1 (14%), CTNNB1 (10%) and ATM (10%). APC, CCND2, CDK4, DAXX, DNMT3A, KDM5C, LRP1B, MSH2 and RB1 were each altered in two cases (7%) and EGFR, ERBB4, KRAS, MDM2, NRAS, PDGFRB, PIK3CA, PTEN and PTCH1 were each altered in a single case (3%). In 17 (59%) of ACC, at least one GA was associated with an available therapeutic or a mechanism-based clinical trial.

Conclusions

Next-generation sequencing can discover targets of therapy for relapsed and metastatic ACC and shows promise to improve outcomes for this aggressive form of cancer.

Microwave-assisted derivatization: application to steroid profiling by gas chromatography/mass spectrometry

Gas chromatography-mass spectrometry (GC-MS) remains as the gold-standard technique for the study of the steroid metabolome. A main limitation is the need of performing a derivatization step since incubation with strong silylations agents for long periods of time (usually 16 h) is required for the derivatization of hindered hydroxyls present in some steroids of interest. In the present work, a rapid, simple and reproducible microwave-assisted derivatization method was developed. In the method, 36 steroids already treated with methoxyamine (2% in pyridine) were silylated with 50 μl of N-trimethylsilylimidazole by using microwave irradiation, and the formed methyloxime-trimethylsilyl derivatives were analyzed by GC-MS. Microwave power and derivatization time silylation conditions were optimized being the optimum conditions 600 W and 3 min respectively. In order to evaluate the usefulness of this technique, the urine steroid profiles for 20 healthy individuals were analyzed. The results of a comparison of microwave irradiation with the classical heating protocol showed similar derivatization yields, thus suggesting that microwave-assisted silylation is a valid tool for the rapid steroid metabolome study.

The 'omics' of adrenocortical tumours for personalized medicine

Pan-genomic analyses of genetic and epigenetic alterations and gene expression profiles are providing important new insights into the pathogenesis and molecular classification of cancers. The technologies and methods used for these studies are rapidly diversifying and improving. The use of such methodologies for the analysis of adrenocortical tumours has revealed clear transcriptomic (mRNA and microRNA expression profiles), epigenomic (DNA methylation profiles) and genomic (DNA mutations and chromosomal alterations) differences between benign and malignant tumours. Interestingly, genomic studies of adrenal cancers have also identified subtypes of malignant tumours, which demonstrate distinct patterns of molecular alterations and are associated with different clinical outcomes. These discoveries have created the opportunity for classifying adrenocortical tumours on the basis of molecular analyses. Following these genomic studies, efforts to develop new molecular tools that improve diagnosis and prognostication of patients with adrenocortical tumours have also been made. This Review describes the progress that has been made towards classification of adrenocortical tumours to date based on key genomic approaches. In addition, the potential for the development and use of various molecular tools to personalize the management of patients with adrenocortical tumours is discussed.

Analysis of circulating microRNAs in adrenocortical tumors

Differential diagnosis of adrenocortical adenoma (ACA) and carcinoma is of pivotal clinical relevance, as the prognosis and clinical management of benign and malignant adrenocortical tumors (ACTs) is entirely different. Circulating microRNAs (miRNAs) are promising biomarker candidates of malignancy in several tumors; however, there are still numerous technical problems associated with their analysis. The objective of our study was to investigate circulating miRNAs in ACTs and to evaluate their potential applicability as biomarkers of malignancy. We have also addressed technical questions including the choice of profiling and reference gene used. A total of 25 preoperative plasma samples obtained from patients with ACAs and carcinomas were studied by microarray and quantitative real-time PCR. None of the three miRNAs (hsa-miR-192, hsa-mir-197 and hsa-miR-1281) found as differentially expressed in plasma samples in our microarray screening could be validated by quantitative real-time PCR. In contrast, of the selected eight miRNAs reported in the literature as differentially expressed in ACT tissues, five (hsa-miR-100, hsa-miR-181b, hsa-miR-184, hsa-miR-210 and hsa-miR-483-5p) showed a statistically significant overexpression in adrenocortical cancer vs adenoma when normalized on hsa-miR-16 as a reference gene. Receiver operator characteristic analysis of data revealed that the combination of dCThsa-miR-210 - dCThsa-miR-181b and dCThsa-miR-100/dCThsa-miR-181b showed the highest diagnostic accuracy (area under curve 0.87 and 0.85, respectively). In conclusion, we have found significant differences in expression of circulating miRNAs between ACAs and carcinomas, but their diagnostic accuracy is not yet high enough for clinical application. Further studies on larger cohorts of patients are needed to assess the diagnostic and prognostic potential application of circulating miRNA markers.

Molecular markers and targeted therapies for adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a lethal disease with poor prognosis and lack of effective therapeutic options. Systemic treatment is often employed to treat patients with advanced ACC, but outcomes are disappointing. During the last decade, some of the causative genetic mutations in sporadic ACCs have been identified. Molecular analysis has had a significant impact on the understanding of the pathogenetic mechanism of ACC development and the evaluation of prognostic and predictive markers. Preclinical investigations and clinical trials of tyrosine kinase inhibitors and anti-angiogenic compounds have been initiated to seek target therapy of ACCs. This review summarizes the current view of molecular alterations involved in the pathophysiology of adrenocortical carcinogenesis. The rationale for testing targeted therapies of ACC is also presented.

MiR-34a and miR-483-5p are candidate serum biomarkers for adrenocortical tumors

BACKGROUND

Nonfunctioning adrenal incidentalomas are common and many patients undergo adrenalectomy to exclude adrenocortical carcinoma (ACC). Recent studies have shown dysregulated microRNA (miRNA) expression in ACC. The objective of this study was to determine the feasibility and diagnostic accuracy of measuring serum miRNAs in patients with benign and malignant adrenocortical neoplasms.

METHOD

Five miRNAs were selected from miRNA profiling studies in ACC (miR-let-7d, -34a, -195, -214, and 483-5p). Total miRNA was extracted from serum samples in patients with malignant and benign adrenal neoplasms. miRNAs levels were measured by quantitative reverse transcript polymerase chain reaction and normalized to miR-16. To determine if miRNAs were secreted from ACC cells, we measured miRNA levels in culture.

RESULTS

Serum samples from 22 patients with cortical adenomas and 17 patients with ACC were analyzed, and all 5 miRNAs were detected. We found greater levels of miR-34a (P = .001) and miR-483-5p (P = .011) in patients with ACC. The area under the receiver operating characteristic curve was 0.81 for miR-34a and 0.74 for miR-438-5p. MiR-34a and miR-483-5p levels in ACC cells were greater in the supernatant at 48 hours compared with intracellular levels.

CONCLUSION

We show that dysregulated miRNAs in ACC are detectable in human serum samples. MiR-34a and miR-483-5p are candidate serum biomarkers for distinguishing between benign and malignant adrenocortical tumors.

Single nucleotide polymorphism array profiling of adrenocortical tumors--evidence for an adenoma carcinoma sequence?

Adrenocortical tumors consist of benign adenomas and highly malignant carcinomas with a still incompletely understood pathogenesis. A total of 46 adrenocortical tumors (24 adenomas and 22 carcinomas) were investigated aiming to identify novel genes involved in adrenocortical tumorigenesis. High-resolution single nucleotide polymorphism arrays (Affymetrix) were used to detect copy number alterations (CNAs) and copy neutral losses of heterozygosity (cnLOH). Genomic clustering showed good separation between adenomas and carcinomas, with best partition including only chromosome 5, which was highly amplified in 17/22 malignant tumors. The malignant tumors had more relevant genomic aberrations than benign tumors, such as a higher median number of recurrent CNA (2631 vs 94), CNAs >100 Kb (62.5 vs 7) and CN losses (72.5 vs 5.5), and a higher percentage of samples with cnLOH (91% vs 29%). Within the carcinoma cohort, a precise genetic pattern (i.e. large gains at chr 5, 7, 12, and 19, and losses at chr 1, 2, 13, 17, and 22) was associated with a better prognosis (overall survival: 72.2 vs 35.4 months, P=0.063). Interestingly, >70% of gains frequent in beningn were also present in malignant tumors. Notch signaling was the most frequently involved pathway in both tumor entities. Finally, a CN gain at imprinted “IGF2” locus chr 11p15.5 appeared to be an early alteration in a multi-step tumor progression, followed by the loss of one or two alleles, associated with increased IGF2 expression, only in carcinomas. Our study serves as database for the identification of genes and pathways, such as Notch signaling, which could be involved in the pathogenesis of adrenocortical tumors. Using these data, we postulate an adenoma-carcinoma sequence for these tumors.

Epigenetic silencing of RASSF1A deregulates cytoskeleton and promotes malignant behavior of adrenocortical carcinoma

Background

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with high mutational heterogeneity and a generally poor clinical outcome. Despite implicated roles of deregulated TP53, IGF-2 and Wnt signaling pathways, a clear genetic association or unique mutational link to the disease is still missing. Recent studies suggest a crucial role for epigenetic modifications in the genesis and/or progression of ACC. This study specifically evaluates the potential role of epigenetic silencing of RASSF1A, the most commonly silenced tumor suppressor gene, in adrenocortical malignancy.

Results

Using adrenocortical tumor and normal tissue specimens, we show a significant reduction in expression of RASSF1A mRNA and protein in ACC. Methylation-sensitive and -dependent restriction enzyme based PCR assays revealed significant DNA hypermethylation of the RASSF1A promoter, suggesting an epigenetic mechanism for RASSF1A silencing in ACC. Conversely, the RASSF1A promoter methylation profile in benign adrenocortical adenomas (ACAs) was found to be very similar to that found in normal adrenal cortex. Enforced expression of ectopic RASSF1A in the SW-13 ACC cell line reduced the overall malignant behavior of the cells, which included impairment of invasion through the basement membrane, cell motility, and solitary cell survival and growth. On the other hand, expression of RASSF1A/A133S, a loss-of-function mutant form of RASSF1A, failed to elicit similar malignancy-suppressing responses in ACC cells. Moreover, association of RASSF1A with the cytoskeleton in RASSF1A-expressing ACC cells and normal adrenal cortex suggests a role for RASSF1A in modulating microtubule dynamics in the adrenal cortex, and thereby potentially blocking malignant progression.

Conclusions

Downregulation of RASSF1A via promoter hypermethylation may play a role in the malignant progression of adrenocortical carcinoma possibly by abrogating differentiation-promoting RASSF1A- microtubule interactions.