@article{SbieraTryfonidouWeigandetal.2016, author = {Sbiera, Silviu and Tryfonidou, Marianna A. and Weigand, Isabel and Grinwis, Guy C. M. and Broeckx, Bart and Herterich, Sabine and Allolio, Bruno and Deutschbein, Timo and Fassnacht, Martin and Meij, Bj{\"o}rn P.}, title = {Lack of Ubiquitin Specific Protease 8 (USP8) Mutations in Canine Corticotroph Pituitary Adenomas}, series = {Plos One}, volume = {11}, journal = {Plos One}, number = {12}, doi = {10.1371/journal.pone.0169009}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148020}, pages = {e0169009}, year = {2016}, abstract = {Purpose Cushing's disease (CD), also known as pituitary-dependent hyperadrenocorticism, is caused by adrenocorticotropic hormone (ACTH)-secreting pituitary tumours. Affected humans and dogs have similar clinical manifestations, however, the incidence of the canine disease is thousand-fold higher. This makes the dog an obvious model for studying the pathogenesis of pituitary-dependent hyperadrenocorticism. Despite certain similarities identified at the molecular level, the question still remains whether the two species have a shared oncogenetic background. Recently, hotspot recurrent mutations in the gene encoding for ubiquitin specific protease 8 (USP8) have been identified as the main driver behind the formation of ACTH-secreting pituitary adenomas in humans. In this study, we aimed to verify whether USP8 mutations also play a role in the development of such tumours in dogs. Methods Presence of USP8 mutations was analysed by Sanger and PCR-cloning sequencing in 38 canine ACTH-secreting adenomas. Furthermore, the role of USP8 and EGFR protein expression was assessed by immunohistochemistry in a subset of 25 adenomas. Results None of the analysed canine ACTH-secreting adenomas presented mutations in the USP8 gene. In a subset of these adenomas, however, we observed an increased nuclear expression of USP8, a phenotype characteristic for the USP8 mutated human tumours, that correlated with smaller tumour size but elevated ACTH production in those tumours. Conclusions Canine ACTH-secreting pituitary adenomas lack mutations in the USP8 gene suggesting a different genetic background of pituitary tumourigenesis in dogs. However, elevated nuclear USP8 protein expression in a subset of tumours was associated with a similar phenotype as in their human counterparts, indicating a possible end-point convergence of the different genetic backgrounds in the two species. In order to establish the dog as a useful animal model for the study of CD, further comprehensive studies are needed.}, language = {en} } @article{AltieriSbieraDellaCasaetal.2017, author = {Altieri, Barbara and Sbiera, Silviu and Della Casa, Silvia and Weigand, Isabel and Wild, Vanessa and Steinhauer, Sonja and Fadda, Guido and Kocot, Arkadius and Bekteshi, Michaela and Mambretti, Egle M. and Rosenwald, Andreas and Pontecorvi, Alfredo and Fassnacht, Martin and Ronchi, Cristina L.}, title = {Livin/BIRC7 expression as malignancy marker in adrenocortical tumors}, series = {Oncotarget}, volume = {8}, journal = {Oncotarget}, number = {6}, doi = {10.18632/oncotarget.14067}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171887}, pages = {9323-9338}, year = {2017}, abstract = {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.}, language = {en} } @article{WeigandRonchiRizkRabinetal.2017, author = {Weigand, Isabel and Ronchi, Cristina L. and Rizk-Rabin, Marthe and Dalmazi, Guido Di and Wild, Vanessa and Bathon, Kerstin and Rubin, Beatrice and Calebiro, Davide and Beuschlein, Felix and Bertherat, J{\´e}r{\^o}me and Fassnacht, Martin and Sbiera, Silviu}, title = {Differential expression of the protein kinase A subunits in normal adrenal glands and adrenocortical adenomas}, series = {Scientific Reports}, volume = {7}, journal = {Scientific Reports}, number = {49}, doi = {10.1038/s41598-017-00125-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157952}, year = {2017}, abstract = {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.}, language = {en} } @article{SbieraKunzWeigandetal.2019, author = {Sbiera, Silviu and Kunz, Meik and Weigand, Isabel and Deutschbein, Timo and Dandekar, Thomas and Fassnacht, Martin}, title = {The new genetic landscape of Cushing's disease: deubiquitinases in the spotlight}, series = {Cancers}, volume = {11}, journal = {Cancers}, number = {11}, issn = {2072-6694}, doi = {10.3390/cancers11111761}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193194}, pages = {1761}, year = {2019}, abstract = {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.}, language = {en} } @article{LacombeSoaresMarianietal.2020, author = {Lacombe, Amanda Meneses Ferreira and Soares, Iber{\^e} Cauduro and Mariani, Beatriz Marinho de Paula and Nishi, Mirian Yumie and Bezerra-Neto, Jo{\~a}o Evangelista and Charchar, Helaine da Silva and Brondani, Vania Balderrama and Tanno, Fabio and Srougi, Victor and Chambo, Jos{\´e} Luiz and Costa de Freitas, Ricardo Miguel and Mendonca, Berenice Bilharinho and Hoff, Ana O. and Almeida, Madson Q. and Weigand, Isabel and Kroiss, Matthias and Zerbini, Maria Claudia Nogueira and Fragoso, Maria Candida Barisson Villares}, title = {Sterol O-acyl transferase 1 as a prognostic marker of adrenocortical carcinoma}, series = {Cancers}, volume = {12}, journal = {Cancers}, number = {1}, issn = {2072-6694}, doi = {10.3390/cancers12010247}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200857}, year = {2020}, abstract = {Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with an unfavorable prognosis. Despite the poor prognosis in the majority of patients, no improvements in treatment strategies have been achieved. Therefore, the discovery of new prognostic biomarkers is of enormous interest. Sterol-O-acyl transferase 1 (SOAT1) is involved in cholesterol esterification and lipid droplet formation. Recently, it was demonstrated that SOAT1 inhibition leads to impaired steroidogenesis and cell viability in ACC. To date, no studies have addressed the impact of SOAT1 expression on ACC prognosis and clinical outcomes. We evaluated SOAT1 expression by quantitative real-time polymerase chain reaction and immunohistochemistry in a tissue microarray of 112 ACCs (Weiss score ≥ 3) from adults treated in a single tertiary center in Brazil. Two independent pathologists evaluated the immunohistochemistry results through a semiquantitative approach (0-4). We aimed to evaluate the correlation between SOAT1 expression and clinical, biochemical and anatomopathological parameters, recurrence-free survival (RFS), progression-free survival (PFS), and overall survival (OS). SOAT1 protein expression was heterogeneous in this cohort, 37.5\% of the ACCs demonstrated a strong SOAT1 protein expression (score > 2), while 62.5\% demonstrated a weak or absent protein expression (score ≤ 2). Strong SOAT1 protein expression correlated with features of high aggressiveness in ACC, such as excessive tumor cortisol secretion (p = 0.01), an advanced disease stage [European Network for the Study of Adrenal Tumors (ENSAT) staging system 3 and 4 (p = 0.011)] and a high Ki67 index (p = 0.002). In multivariate analysis, strong SOAT1 protein expression was an independent predictor of a reduced OS (hazard ratio (HR) 2.15, confidence interval (CI) 95\% 1.26-3.66; p = 0.005) in all patients (n = 112), and a reduced RFS (HR 2.1, CI 95\% 1.09-4.06; p = 0.027) in patients with localized disease at diagnosis (n = 83). Our findings demonstrated that SOAT1 protein expression has prognostic value in ACC and reinforced the importance of investigating SOAT1 as a possible therapeutic target for patients with ACC.}, language = {en} } @article{LandwehrAltieriSchreineretal.2020, author = {Landwehr, Laura-Sophie and Altieri, Barbara and Schreiner, Jochen and Sbiera, Iuliu and Weigand, Isabel and Kroiss, Matthias and Fassnacht, Martin and Sbiera, Silviu}, title = {Interplay between glucocorticoids and tumor-infiltrating lymphocytes on the prognosis of adrenocortical carcinoma}, series = {Journal for ImmunoTherapy of Cancer}, volume = {8}, journal = {Journal for ImmunoTherapy of Cancer}, doi = {10.1136/jitc-2019-000469}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229893}, year = {2020}, abstract = {Background Adrenocortical carcinoma (ACC) is a rare endocrine malignancy. Tumor-related glucocorticoid excess is present in similar to 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.}, language = {en} } @phdthesis{Weigand2021, author = {Weigand, Isabel}, title = {Consequences of Protein Kinase A mutations in adrenocortical cells and tumours}, doi = {10.25972/OPUS-16064}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-160646}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {Adrenal Cushing's Syndrome (CS) is a rare but life-threatening disease and therefore it is of great importance to understand the pathogenesis leading to adrenal CS. It is well accepted that Protein Kinase A (PKA) signalling mediates steroid secretion in adrenocortical cells. PKA is an inactive heterotetramer, consisting of two catalytic and two regulatory subunits. Upon cAMP binding to the regulatory subunits, the catalytic subunits are released and are able to phosphorylate their target proteins. Recently, activating somatic mutations affecting the catalytic subunit a of PKA have been identified in a sub-population of cortisol-producing adenomas (CPAs) associated with overt CS. Interestingly, the PKA regulatory subunit IIb has long been known to have significantly lower protein levels in a sub-group of CPAs compared to other adrenocortical tumours. Yet, it is unknown, why these CPAs lack the regulatory subunit IIb, neither are any functional consequences nor are the underlying regulation mechanisms leading to reduced RIIb levels known. The results obtained in this thesis show a clear connection between Ca mutations and reduced RIIb protein levels in CPAs but not in other adrenocortical tumours. Furthermore, a specific pattern of PKA subunit expression in the different zones of the normal adrenal gland is demonstrated. In addition, a Ca L206R mutation-mediated degradation of RIIb was observed in adrenocortical cells in vitro. RIIb degradation was found to be mediated by caspases and by performing mutagenesis experiments of the regulatory subunits IIb and Ia, S114 phosphorylation of RIIb was identified to make RIIb susceptible for degradation. LC-MS/MS revealed RIIb interaction partners to differ in the presence of either Ca WT and Ca L206R. These newly identified interaction partners are possibly involved in targeting RIIb to subcellular compartments or bringing it into spatial proximity of degrading enzymes. Furthermore, reducing RIIb protein levels in an in vitro system were shown to correlate with increased cortisol secretion also in the absence of PRKACA mutations. The inhibiting role of RIIb in cortisol secretion demonstrates a new function of this regulatory PKA subunit, improving the understanding of the complex regulation of PKA as key regulator in many cells.}, subject = {Cushing-Syndrom}, language = {en} } @article{WeigandRonchiVanselowetal.2021, author = {Weigand, Isabel and Ronchi, Cristina L. and Vanselow, Jens T. and Bathon, Kerstin and Lenz, Kerstin and Herterich, Sabine and Schlosser, Andreas and Kroiss, Matthias and Fassnacht, Martin and Calebiro, Davide and Sbiera, Silviu}, title = {PKA Cα subunit mutation triggers caspase-dependent RIIβ subunit degradation via Ser\(^{114}\) phosphorylation}, series = {Science Advances}, volume = {7}, journal = {Science Advances}, number = {8}, doi = {10.1126/sciadv.abd4176}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-270445}, year = {2021}, abstract = {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 Ser\(^{114}\) 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.}, language = {en} } @article{EckhardtSbieraKrebsetal.2022, author = {Eckhardt, Carolin and Sbiera, Iuliu and Krebs, Markus and Sbiera, Silviu and Spahn, Martin and Kneitz, Burkhard and Joniau, Steven and Fassnacht, Martin and K{\"u}bler, Hubert and Weigand, Isabel and Kroiss, Matthias}, title = {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}, series = {Prostate Cancer and Prostatic Diseases}, volume = {25}, journal = {Prostate Cancer and Prostatic Diseases}, number = {3}, issn = {1476-5608}, doi = {10.1038/s41391-021-00431-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-271819}, pages = {484-490}, year = {2022}, abstract = {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.}, language = {en} }