Reduced Levels of Misfolded and Aggregated Mutant p53 by Proteostatic Activation.

In malignant cancer, excessive amounts of mutant p53 often lead to its aggregation, a feature that was recently identified as druggable. Here, we describe that induction of a heat shock-related stress response mediated by Foldlin, a small-molecule tool compound, reduces the protein levels of misfolded/aggregated mutant p53, while contact mutants or wild-type p53 remain largely unaffected. Foldlin also prevented the formation of stress-induced p53 nuclear inclusion bodies. Despite our inability to identify a specific molecular target, Foldlin also reduced protein levels of aggregating SOD1 variants. Finally, by screening a library of 778 FDA-approved compounds for their ability to reduce misfolded mutant p53, we identified the proteasome inhibitor Bortezomib with similar cellular effects as Foldlin. Overall, the induction of a cellular heat shock response seems to be an effective strategy to deal with pathological protein aggregation. It remains to be seen however, how this strategy can be translated to a clinical setting.

ALK Amplification and Rearrangements Are Recurrent Targetable Events in Congenital and Adult Glioblastoma.

PURPOSE: Anaplastic lymphoma kinase (ALK) aberrations have been identified in pediatric-type infant gliomas, but their occurrence across age groups, functional effects, and treatment response has not been broadly established. EXPERIMENTAL DESIGN: We performed a comprehensive analysis of ALK expression and genomic aberrations in both newly generated and retrospective data from 371 glioblastomas (156 adult, 205 infant/pediatric, and 10 congenital) with in vitro and in vivo validation of aberrations. RESULTS: ALK aberrations at the protein or genomic level were detected in 12% of gliomas (45/371) in a wide age range (0-80 years). Recurrent as well as novel ALK fusions (LRRFIP1-ALK, DCTN1-ALK, PRKD3-ALK) were present in 50% (5/10) of congenital/infant, 1.4% (3/205) of pediatric, and 1.9% (3/156) of adult GBMs. ALK fusions were present as the only candidate driver in congenital/infant GBMs and were sometimes focally amplified. In contrast, adult ALK fusions co-occurred with other oncogenic drivers. No activating ALK mutations were identified in any age group. Novel and recurrent ALK rearrangements promoted STAT3 and ERK1/2 pathways and transformation in vitro and in vivo. ALK-fused GBM cellular and mouse models were responsive to ALK inhibitors, including in patient cells derived from a congenital GBM. Relevant to the treatment of infant gliomas, we showed that ALK protein appears minimally expressed in the forebrain at perinatal stages, and no gross effects on perinatal brain development were seen in pregnant mice treated with the ALK inhibitor ceritinib. CONCLUSIONS: These findings support use of brain-penetrant ALK inhibitors in clinical trials across infant, pediatric, and adult GBMs. See related commentary by Mack and Bertrand, p. 2567.

Acetazolamide to increase natriuresis in congestive heart failure at high risk for diuretic resistance.

AIMS: To investigate the effects of acetazolamide on natriuresis, decongestion, kidney function and neurohumoral activation in acute heart failure (AHF). METHODS AND RESULTS: This prospective, two-centre study included 34 AHF patients on loop diuretics with volume overload. All had a serum sodium concentration < 135 mmol/L and/or serum urea/creatinine ratio > 50 and/or an admission serum creatinine increase of > 0.3 mg/dL compared to baseline. Patients were randomised towards acetazolamide 250-500 mg daily plus bumetanide 1-2 mg bid vs. high-dose loop diuretics (bumetanide bid with daily dose twice the oral maintenance dose). The primary endpoint was natriuresis after 24 h. Natriuresis after 24 h was similar in the combinational treatment vs. loop diuretic only arm (264 ± 126 vs. 234 ± 133 mmol; P = 0.515). Loop diuretic efficiency, defined as natriuresis corrected for loop diuretic dose, was higher in the group receiving acetazolamide (84 ± 46 vs. 52 ± 42 mmol/mg bumetanide; P = 0.048). More patients in the combinational treatment arm had an increase in serum creatinine levels > 0.3 mg/dL (P = 0.046). N-terminal pro-B-type natriuretic peptide reduction and peak neurohumoral activation within 72 h were comparable among treatment arms. There was a non-significant trend towards lower all-cause mortality or heart failure readmissions in the group receiving acetazolamide with low-dose loop diuretics vs. high-dose loop diuretic monotherapy (P = 0.098). CONCLUSION: Addition of acetazolamide increases the natriuretic response to loop diuretics compared to an increase in loop diuretic dose in AHF at high risk for diuretic resistance. TRIAL REGISTRATION: ClinicalTrials.gov NCT01973335.

Spironolactone to increase natriuresis in congestive heart failure with cardiorenal syndrome.

BACKGROUND: Signs and symptoms of volume overload are the most frequent reason for hospital admission in acute heart failure (AHF). Diuretics are mainstay treatment, but their optimal type and dose regimen remain unclear, especially in patients with cardiorenal syndrome. METHODS: This prospective study aimed to include 80 AHF patients with volume overload and cardiorenal syndrome. Through a 2 × 2 factorial design, patients were randomised towards (1) combinational treatment with acetazolamide and low-dose loop diuretics versus high-dose loop diuretics; and (2) open-label oral spironolactone 25 mg OD given upfront versus at discharge. Here reported are the results of the spironolactone treatment arm after complete follow-up of 34/80 patients (since the study was stopped because of slow recruitment). The primary study end-point was incident hypokalaemia (<3.5 mmol/L) or hyperkalaemia (>5.5 mmol/L). RESULTS: Serum potassium derangements were numerically less frequent in the upfront versus discharge spironolactone group, yet this result was underpowered due to incomplete study recruitment (hyperkalaemia: 6% vs. 11%; hypokalaemia: 13% vs. 28%, respectively; p-value = .270). Natriuresis after 24 h was higher in the upfront vs. discharge spironolactone group (314 ± 142 vs. 200 ± 91 mmol/L, respectively; p-value = .010). Relative change in plasma NT-proBNP level after 72 h was similar among both groups (-16 ± 29% vs. -5 ± 45%, respectively; p value = .393), with no difference in all-cause mortality (p-value = .682) or the combination of all-cause mortality and heart failure readmission (p-value = .799). DISCUSSION: Spironolactone use upfront in AHF patients at high risk for cardiorenal syndrome is safe and increases natriuresis.