Objective To screen for CLCN2 mutations in apparently sporadic cases of aldosterone-producing adenomas (APAs). Description Recently, CLCN2, encoding for the voltage-gated chloride channel protein 2 (ClC-2), was identified to be mutated in familial hyperaldosteronism II (FH II). So far, somatic mutations in CLCN2 have not been reported in sporadic cases of APAs. We screened 80 apparently sporadic APAs for mutations in CLCN2. One somatic mutation was identified at p.Gly24Asp in CLCN2. The male patient had a small adenoma in size but high aldosterone levels preoperatively. Postoperatively, the patient had normal aldosterone levels and was clinically cured. Conclusion In this study, we identified a CLCN2 mutation in a sporadic APA comprising about 1% of all APAs investigated. This mutation was complementary to mutations in other susceptibility genes for sporadic APAs and may thus be a driving mutation in APA formation.

n/

BackgroundNOTCH1 PEST domain mutations in chronic lymphocytic leukemia have recently been shown to be of prognostic relevance. Both NOTCH1 and NOTCH2 are constitutively activated in B-cell CLL but not expressed in normal B cells and may be involved in survival and resistance to apoptosis in CLL. We screened for mutations in different parts of both NOTCH1 and NOTCH2 genes and related the changes to survival and other known risk factors.MethodsIn a cohort of 209 CLL patients, we used single strand conformation analysis to determine which of the samples carrying the NOTCH mutations and direct dideoxy sequencing was used to determine the exact nucleotide changes. Kaplan-Meier curves and log rank test were used to determine overall survival for NOTCH1 mutated cases and Cox regression analysis was used to calculate hazardous ratios.ResultsIn the present study, we found NOTCH1 PEST domain mutations in 6.7% of the cases. A shorter overall survival was found in patients with NOTCH1 mutations compared to wildtype (p = 0.049). Further, we also examined the extracellular and the heterodimerisation domains of the NOTCH1 gene and the PEST domain and heterodimerisation domain of the NOTCH2 gene, but no mutations were found in these regions. NOTCH1 mutations were most commonly observed in patients with unmutated IGHV gene (10/14), and associated with a more aggressive disease course. In addition, NOTCH1 mutations were almost mutually exclusive with TP53 mutations. In the combined group of NOTCH1 (6.7%) or TP53 (6.2%) mutations, a significant difference in overall survival compared to the wildtype NOTCH1 and TP53 was found (p = 0.002).ConclusionsBoth NOTCH1 and TP53 mutations seem to be independent predictive markers for worse outcome in CLL-patients and this study emphasizes the contention that NOTCH1 mutations is a novel risk marker.

Hypertension is a common medical condition and affects approximately 20% of the population in developed countries. Primary aldosteronism is the most common form of secondary hypertension and affects 8-13% of patients with hypertension. The two most common causes of primary aldosteronism are aldosterone-producing adenoma and bilateral adrenal hyperplasia. Familial hyperaldosteronism types I, II and III are the known genetic syndromes, in which both adrenal glands produce excessive amounts of aldosterone. However, only a minority of patients with primary aldosteronism have one of these syndromes. Several novel susceptibility genes have been found to be mutated in aldosterone-producing adenomas: KCNJ5, ATP1A1, ATP2B3, CTNNB1, CACNA1D, CACNA1H and ARMC5. This review describes the genes currently known to be responsible for primary aldosteronism, discusses the origin of aldosterone-producing adenomas and considers the future clinical implications based on these novel insights.

Targeted protein degradation is a rapidly advancing and expanding therapeutic approach. Drugs that degrade GSPT1 via the CRL4 CRBN ubiquitin ligase are a new class of cancer therapy in active clinical development with evidence of activity against acute myeloid leukemia in early phase trials.However, other than activation of the integrated stress response, the downstream effects of GSPT1 degradation leading to cell death are largely undefined, and no murine models are available to study these agents. We identified the domains of GSPT1 essential for cell survival and show that GSPT1 degradation leads to impaired translation termination, activation of the integrated stress response pathway, and TP53-independent cell death. CRISPR-Cas9 screens implicated decreased translation initiation as protective to GSPT1 degradation, suggesting that cells with higher levels of translation are more susceptible to GSPT1 degradation. We defined two Crbn amino acids that prevent Gspt1 degradation in mice, generated a knock-in mouse with alteration of these residues, and demonstrated the efficacy of GSPT1-degrading drugs in vivo with relative sparing of numbers and function of long-term hematopoietic stem cells. Our results provide a mechanistic basis for the use of GSPT1 degraders for the treatment of cancer, including

No abstract

Background: Enzymes of tricarboxylic acid (TCA) have recently been recognized as tumor suppressors. Mutations in the SDHB subunit of succinate dehydrogenase (SDH) cause pheochromocytomas and paragangliomas (PCCs/PGLs) and predispose patients to malignant disease with poor prognosis. Methods: Using the human pheochromocytoma cell line (hPheo1), we knocked down SDHB gene expression using CRISPR-cas9 technology. Results: Microarray gene expression analysis showed that >500 differentially expressed gene targets, about 54%, were upregulated in response to SDHB knock down. Notably, genes involved in glycolysis, hypoxia, cell proliferation, and cell differentiation were up regulated, whereas genes involved in oxidative phosphorylation (OXPHOS) were downregulated. In vitro studies show that hPheo1 proliferation is not affected negatively and the cells that survive by shifting their metabolism to the use of glutamine as an alternative energy source and promote OXPHOS activity. Knock down of SDHB expression results in a significant increase in GLUD1 expression in hPheo1 cells cultured as monolayer or as 3D culture. Analysis of TCGA data confirms the enhancement of GLUD1 in SDHB mutated/low expressed PCCs/PGLs. Conclusions: Our data suggest that the downregulation of SDHB in PCCs/PGLs results in increased GLUD1 expression and may represent a potential biomarker and therapeutic target in SDHB mutated tumors and SDHB loss of activity-dependent diseases.

Phaeochromocytomas and paragangliomas (PPGLs) are neuroendocrine catecholamine-producing tumours that may progress into inoperable metastatic disease. Treatment options for metastatic disease are limited, indicating a need for functional studies to identify pharmacologically targetable pathophysiological mechanisms, which require biologically relevant experimental models. Recently, a human progenitor phaeochromocytoma cell line named “hPheo1” was established, but its genotype has not been characterised. Performing exome sequencing analysis, we identified a KIF1B T827I mutation, and the oncogenic NRAS Q61K mutation. While KIF1B mutations are recurring somatic events in PPGLs, NRAS mutations have hitherto not been detected in PPGLs. Therefore, we aimed to assess its implications for the hPheo1 cell line, and possible relevance for the pathophysiology of PPGLs. We found that transient downregulation of NRAS in hPheo1 led to elevated expression of genes associated with cell adhesion, and enhanced adhesion to hPheo1 cells’ extracellular matrix. Analyses of previously published mRNA data from two independent PPGL patient cohorts (212 tissue samples) revealed a subcluster of PPGLs featuring hyperactivated RAS pathway-signalling and under-expression of cell adhesion-related gene expression programs. Thus, we conclude that NRAS activity in hPheo1 decreases adhesion to their own extracellular matrix and mirrors a transcriptomic RAS-signalling-related phenomenon in PPGLs.