A druggable conformational switch in the c-MYC transactivation domain.

The c-MYC oncogene is activated in over 70% of all human cancers. The intrinsic disorder of the c-MYC transcription factor facilitates molecular interactions that regulate numerous biological pathways, but severely limits efforts to target its function for cancer therapy. Here, we use a reductionist strategy to characterize the dynamic and structural heterogeneity of the c-MYC protein. Using probe-based Molecular Dynamics (MD) simulations and machine learning, we identify a conformational switch in the c-MYC amino-terminal transactivation domain (termed coreMYC) that cycles between a closed, inactive, and an open, active conformation. Using the polyphenol epigallocatechin gallate (EGCG) to modulate the conformational landscape of coreMYC, we show through biophysical and cellular assays that the induction of a closed conformation impedes its interactions with the transformation/transcription domain-associated protein (TRRAP) and the TATA-box binding protein (TBP) which are essential for the transcriptional and oncogenic activities of c-MYC. Together, these findings provide insights into structure-activity relationships of c-MYC, which open avenues towards the development of shape-shifting compounds to target c-MYC as well as other disordered transcription factors for cancer treatment.

A proof-of-principle study for the point-of-care detection of ESBL (CTX-M) by NG-Test® CTX-M MULTI lateral flow assay in urine samples using a simplified method for use in a resource-limited setting.

Background: The rise of extended-spectrum ß-lactamase-producing Enterobacterales (ESBL-E) in low- and middle-income countries limits treatment options, leading to the frequent use of broad-spectrum antibiotics. Reducing time-to-result for a urinary infection can facilitate correct antibiotic treatment and support antimicrobial and diagnostic stewardship measures. This study compared two simplified enrichment methods for detecting CTX-M directly from urine specimens. Methods: Two enrichment methods, namely centrifugation of 2 mL urine and filtration of 1 mL urine using the DirecTool adaptor, were compared using 20 culture-positive urine samples (20 suspected ESBL-E and 20 non-ESBL-E). CTX-M production was detected using a lateral flow assay (LFA), NG-Test® CTX-MMULTI. The presence of bla CTX-M genes was confirmed by whole-genome sequencing (WGS). Results: The results of both enrichment methods were identical, with a sensitivity of 87.5% and a specificity of 100%. In 19/20 (95%) of the urine samples, the results of the CTX-M LFA were identical with the phenotypic confirmation and WGS. Both methods could detect ESBL-E bacteriuria with ≥104 cfu/mL. All ESBL-E-negative samples were identified accurately. Both enrichment methods yielded negative results in one ESBL-E-positive (CTX-M-15) sample despite phenotypic and genotypic confirmation of ESBL production. High leukocyte count (>500 cells/µL), the presence of boric acid or polymicrobial samples did not appear to impact the performance of both enrichment methods. Conclusions: Our study underscores the feasibility of directly detecting CTX-M in urine. Simplified enrichment methods, particularly with a filtration kit, enhance the assay's practicality, rendering it suitable for use in primary care, emergency departments or remote laboratories without sophisticated equipment.

Wall Shear Stress Measured with 4D Flow CMR Correlates with Biomarkers of Inflammation and Collagen Synthesis in Mild-to-Moderate Ascending Aortic Dilation and Tricuspid Aortic Valves.

AIMS: Understanding the mechanisms underlying ascending aortic dilation is imperative for refined risk stratification of these patients, particularly among incidentally identified patients, most commonly presenting with tricuspid valves. The aim of this study was to explore associations between ascending aortic hemodynamics, assessed using four-dimensional flow cardiovascular magnetic resonance imaging (4D Flow CMR), and circulating biomarkers in aortic dilation. METHODS AND RESULTS: Forty-seven cases with aortic dilation (diameter ≥40 mm) and 50 sex-and age-matched controls (diameter <40 mm), all with tricuspid aortic valves, underwent 4D flow CMR and venous blood sampling. Associations between flow displacement, wall shear stress (WSS), and oscillatory shear index in the ascending aorta derived from 4D Flow CMR, and biomarkers including interleukin-6, collagen type I α1 chain, metalloproteinases (MMPs), and inhibitors of MMPs derived from blood plasma, were investigated. Cases with dilation exhibited lower peak systolic WSS, higher flow displacement, and higher mean oscillatory shear index compared to controls without dilation. No significant differences in biomarkers were observed between the groups. Correlations between hemodynamics and biomarkers were observed, particularly between maximum time-averaged WSS and interleukin-6 (r = 0.539, p < 0.001), and maximum oscillatory shear index and collagen type I α1 chain (r = -0.575, p < 0.001 in cases). CONCLUSION: Significant associations were discovered between 4D flow CMR derived whole-cardiac cycle WSS and circulating biomarkers representing inflammation and collagen synthesis, suggesting an intricate interplay between hemodynamics and the processes of inflammation and collagen synthesis in patients with early aortic dilation and tricuspid aortic valves.

Evaluation of screening algorithms to detect rectal colonization with carbapenemase-producing Enterobacterales in a resource-limited setting.

Objectives: To improve and rationalize the detection of carbapenemase-producing Enterobacterales (CPE) in rectal swabs in a high-prevalence and resource-constrained setting, addressing surveillance challenges typically encountered in laboratories with limited resources. Methods: A point prevalence survey (PPS) was conducted on 15 August 2022, in a provincial children's hospital in northern Vietnam. Rectal swab samples of all admitted children were collected and plated on a selective medium for carbapenem-resistant Enterobacterales (CRE). Species identification and antimicrobial susceptibility testing (AST) were performed by MALDI-TOF, and VITEK2 XL and interpreted according to CLSI breakpoints (2022). Carbapenemases were detected by the carbapenem inactivation method (CIM) and quantitative real-time PCR (qRT-PCR). Results: Rectal swab samples were obtained from 376 patients. Of 178 isolates growing on the CRE screening agar, 140 isolates were confirmed as Enterobacterales of which 118 (84.3%) isolates were resistant to meropenem and/or ertapenem. CIM and PCR showed that 90/118 (76.3%) were carbapenemase producers. Overall, 83/367 (22.6%) were colonized by CPE. Klebsiella pneumoniae, Escherichia coli and Enterobacter cloacae complex were the most common CPE detected, with NDM as the predominant carbapenemase (78/90; 86.7%). Phenotypic resistance to meropenem was the best predictor of CPE production (sensitivity 85.6%, specificity 100%) compared with ertapenem resistance (95.6% sensitivity, 36% specificity). CIM was 100% concordant with PCR in detecting carbapenemases. Conclusions: These findings underscore the effectiveness of meropenem resistance as a robust indicator of the production of carbapenemases and the reliability of the CIM method to detect such carbapenemases in resource-limited settings where the performance of molecular methods is not possible.