The MYCN 5' UTR as a therapeutic target in neuroblastoma.

Tumor MYCN amplification is seen in high-risk neuroblastoma, yet direct targeting of this oncogenic transcription factor has been challenging. Here, we take advantage of the dependence of MYCN-amplified neuroblastoma cells on increased protein synthesis to inhibit the activity of eukaryotic translation initiation factor 4A1 (eIF4A1) using an amidino-rocaglate, CMLD012824. Consistent with the role of this RNA helicase in resolving structural barriers in 5' untranslated regions (UTRs), CMLD012824 increased eIF4A1 affinity for polypurine-rich 5' UTRs, including that of the MYCN and associated transcripts with critical roles in cell proliferation. CMLD012824-mediated clamping of eIF4A1 spanned the full lengths of mRNAs, while translational inhibition was mediated through 5' UTR binding in a cap-dependent and -independent manner. Finally, CMLD012824 led to growth inhibition in MYCN-amplified neuroblastoma models without generalized toxicity. Our studies highlight the key role of eIF4A1 in MYCN-amplified neuroblastoma and demonstrate the therapeutic potential of disrupting its function.

Proteomic Discovery of RNA-Protein Molecular Clamps Using a Thermal Shift Assay with ATP and RNA (TSAR).

Uncompetitive inhibition is an effective strategy for suppressing dysregulated enzymes and their substrates, but discovery of suitable ligands depends on often-unavailable structural knowledge and serendipity. Hence, despite surging interest in mass spectrometry-based target identification, proteomic studies of substrate-dependent target engagement remain sparse. Herein, we describe the Thermal Shift Assay with ATP and RNA (TSAR) as a template for proteome-wide discovery of substrate-dependent ligand binding. Using proteomic thermal shift assays, we show that simple biochemical additives can facilitate detection of target engagement in native cell lysates. We apply our approach to rocaglates, a family of molecules that specifically clamp RNA to eukaryotic translation initiation factor 4A (eIF4A), DEAD-box helicase 3X (DDX3X), and potentially other members of the DEAD-box (DDX) family of RNA helicases. To identify unexpected interactions, we optimized a target class-specific thermal denaturation window and evaluated ATP analog and RNA probe dependencies for key rocaglate-DDX interactions. We report novel DDX targets of the rocaglate clamping spectrum, confirm that DDX3X is a common target of several widely studied analogs, and provide structural insights into divergent DDX3X affinities between synthetic rocaglates. We independently validate novel targets of high-profile rocaglates, including the clinical candidate Zotatifin (eFT226), using limited proteolysis-mass spectrometry and fluorescence polarization experiments. Taken together, our study provides a model for screening uncompetitive inhibitors using a systematic chemical-proteomics approach to uncover actionable DDX targets, clearing a path towards characterization of novel molecular clamps and associated RNA helicase targets.

A chemical screen identifies structurally diverse metal chelators with activity against the fungal pathogen Candida albicans.

Candida albicans, one of the most prevalent human fungal pathogens, causes diverse diseases extending from superficial infections to deadly systemic mycoses. Currently, only three major classes of antifungal drugs are available to treat systemic infections: azoles, polyenes, and echinocandins. Alarmingly, the efficacy of these antifungals against C. albicans is hindered both by basal tolerance toward the drugs and the development of resistance mechanisms such as alterations of the drug's target, modulation of stress responses, and overexpression of efflux pumps. Thus, the need to identify novel antifungal strategies is dire. To address this challenge, we screened 3,049 structurally-diverse compounds from the Boston University Center for Molecular Discovery (BU-CMD) chemical library against a C. albicans clinical isolate and identified 17 molecules that inhibited C. albicans growth by >80% relative to controls. Among the most potent compounds were CMLD013360, CMLD012661, and CMLD012693, molecules representing two distinct chemical scaffolds, including 3-hydroxyquinolinones and a xanthone natural product. Based on structural insights, CMLD013360, CMLD012661, and CMLD012693 were hypothesized to exert antifungal activity through metal chelation. Follow-up investigations revealed all three compounds exerted antifungal activity against non-albicans Candida, including Candida auris and Candida glabrata, with the xanthone natural product CMLD013360 also displaying activity against the pathogenic mould Aspergillus fumigatus. Media supplementation with metallonutrients, namely ferric or ferrous iron, rescued C. albicans growth, confirming these compounds act as metal chelators. Thus, this work identifies and characterizes two chemical scaffolds that chelate iron to inhibit the growth of the clinically relevant fungal pathogen C. albicansIMPORTANCEThe worldwide incidence of invasive fungal infections is increasing at an alarming rate. Systemic candidiasis caused by the opportunistic pathogen Candida albicans is the most common cause of life-threatening fungal infection. However, due to the limited number of antifungal drug classes available and the rise of antifungal resistance, an urgent need exists for the identification of novel treatments. By screening a compound collection from the Boston University Center for Molecular Discovery (BU-CMD), we identified three compounds representing two distinct chemical scaffolds that displayed activity against C. albicans. Follow-up analyses confirmed these molecules were also active against other pathogenic fungal species including Candida auris and Aspergillus fumigatus. Finally, we determined that these compounds inhibit the growth of C. albicans in culture through iron chelation. Overall, this observation describes two novel chemical scaffolds with antifungal activity against diverse fungal pathogens.

Synthesis of Neocannabinoids Using Controlled Friedel-Crafts Reactions.

A one-step transformation to produce 8,9-dihydrocannabidiol (H2CBD) and related "neocannabinoids" via controlled Friedel-Crafts reactions is reported. Experimental and computational studies probing the mechanism of neocannabinoid synthesis from cyclic allylic alcohol and substituted resorcinol reaction partners provide understanding of the kinetic and thermodynamic factors driving regioselectivity for the reaction. Herein, we present the reaction scope for neocannabinoid synthesis including the production of both normal and abnormal isomers under both kinetic and thermodynamic control. Discovery and optimization of this one-step protocol between various allylic alcohols and resorcinol derivatives are discussed and supported with density functional theory calculations.

Patients' Perceived Level of Clinician Knowledge of Transgender Health Care, Self-rated Health, and Psychological Distress Among Transgender Adults.

Importance: Transgender, gender nonbinary, and genderqueer people are at increased risk for negative health outcomes, and medical school education is currently lacking on inclusion of these topics. However, there is little evidence of an association of clinician knowledge with the health of transgender people. Objective: To evaluate the associations of patients' perceptions of clinician knowledge with self-rated health and severe psychological distress among transgender people. Design, Setting, and Participants: In this cross-sectional study, a secondary data analysis of the 2015 US Transgender Survey (a survey of transgender, gender nonbinary, and genderqueer adults conducted across 50 states) Washington, DC, US territories, and US military bases in 2015 was performed. Data were analyzed from February to November 2022. Exposures: Patients' perception of their clinician's knowledge about transgender health care. Main Outcomes and Measures: Self-rated health, dichotomized as poor or fair vs excellent, very good, or good, and severe psychological distress (scoring a validated threshold of ≥13 on the Kessler Psychological Distress Scale). Results: The sample included a total of 27 715 respondents (9238 transgender women [33.3%; 55.1% weighted; 95% CI, 53.4%-56.7%], 22 658 non-Hispanic White individuals [81.8%; 65.6% weighted; 95% CI, 63.7%-67.5%], and 4085 individuals aged 45-64 years [14.7%; 33.8% weighted; 95% CI, 32.0%-35.5%]). Of 23 318 individuals who answered questions regarding their perceptions of their clinicians' level of knowledge, 5732 (24.6%) reported their clinician knows almost everything about transgender care, 4083 (17.5%) reported their clinician knows most things, 3446 (14.8%) reported their clinician knows some things, 2680 (11.5%) reported their clinician knows almost nothing, and 7337 (31.5%) reported they were unsure. Nearly 1 in 4 transgender adults (5612 of 23 557 individuals [23.8%]) reported having to teach their clinician about transgender people. In total, 3955 respondents (19.4%; 20.8% weighted; 95% CI, 19.2%-22.6%) reported fair or poor self-rated health and 7392 (36.9%; 28.4% weighted, 95% CI, 26.9%-30.1%) met the criteria for severe psychological distress. After adjusting for covariates, compared with individuals who reported their clinician knows almost everything about transgender care, exposure to clinicians with lower perceived levels of knowledge about transgender care was associated with significantly higher odds of fair or poor self-rated health (adjusted odds ratio [aOR] for knowing almost nothing, 2.63; 95% CI, 1.76-3.94; aOR for unsure, 1.81; 95% CI, 1.28-2.56) and severe psychological distress (aOR for knowing almost nothing, 2.33; 95% CI, 1.61-3.37; aOR for unsure, 1.37; 95% CI, 1.05-1.79). Respondents who had to teach a clinician about transgender people had higher odds of reporting fair or poor self-rated health (aOR, 1.67; 95% CI, 1.31-2.13) and severe psychological distress (aOR, 1.49; 95% CI, 1.21-1.83) compared with those who did not. Conclusion and Relevance: The findings of this cross-sectional study suggest that there is an association between perceived clinician knowledge about transgender people and self-rated health and psychological distress among transgender people. These results highlight the importance of integration and enhancement of transgender health in medical education curriculum as a necessary intervention to improve the health of transgender people.

Exploring the targeting spectrum of rocaglates among eIF4A homologs.

Inhibition of eukaryotic translation initiation through unscheduled RNA clamping of the DEAD-box (DDX) RNA helicases eIF4A1 and eIF4A2 has been documented for pateamine A (PatA) and rocaglates-two structurally different classes of compounds that share overlapping binding sites on eIF4A. Clamping of eIF4A to RNA causes steric blocks that interfere with ribosome binding and scanning, rationalizing the potency of these molecules since not all eIF4A molecules need to be engaged to elicit a biological effect. In addition to targeting translation, PatA and analogs have also been shown to target the eIF4A homolog, eIF4A3-a helicase necessary for exon junction complex (EJC) formation. EJCs are deposited on mRNAs upstream of exon-exon junctions and, when present downstream from premature termination codons (PTCs), participate in nonsense-mediated decay (NMD), a quality control mechanism aimed at preventing the production of dominant-negative or gain-of-function polypeptides from faulty mRNA transcripts. We find that rocaglates can also interact with eIF4A3 to induce RNA clamping. Rocaglates also inhibit EJC-dependent NMD in mammalian cells, but this does not appear to be due to induced eIF4A3-RNA clamping, but rather a secondary consequence of translation inhibition incurred by clamping eIF4A1 and eIF4A2 to mRNA.

Discovery of pyrazolopyrrolidinones as potent, broad-spectrum inhibitors of Leishmania infection.

Introduction: Leishmaniasis is a parasitic disease that affects more than 1 million people worldwide annually, predominantly in resource-limited settings. The challenge in compound development is to exhibit potent activity against the intracellular stage of the parasite (the stage present in the mammalian host) without harming the infected host cells. We have identified a compound series (pyrazolopyrrolidinones) active against the intracellular parasites of Leishmania donovani and L. major; the causative agents of visceral and cutaneous leishmaniasis in the Old World, respectively. Methods: In this study, we performed medicinal chemistry on a newly discovered antileishmanial chemotype, with over 100 analogs tested. Studies included assessments of antileishmanial potency, toxicity towards host cells, and in vitro ADME screening of key drug properties. Results and discussion: Members of the series showed high potency against the deadliest form, visceral leishmaniasis (approximate EC50 ≥ 0.01 µM without harming the host macrophage up to 10.0 µM). In comparison, the most efficient monotherapy treatment for visceral leishmaniasis is amphotericin B, which presents similar activity in the same assay (EC50 = 0.2 µM) while being cytotoxic to the host cell at 5.0 µM. Continued development of this compound series with the Discovery Partnership with Academia (DPAc) program at the GlaxoSmithKline Diseases of the Developing World (GSK DDW) laboratories found that the compounds passed all of GSK's criteria to be defined as a potential lead drug series for leishmaniasis. Conclusion: Here, we describe preliminary structure-activity relationships for antileishmanial pyrazolopyrrolidinones, and our progress towards the identification of candidates for future in vivo assays in models of visceral and cutaneous leishmaniasis.

BRCA mutational status shapes the stromal microenvironment of pancreatic cancer linking clusterin expression in cancer associated fibroblasts with HSF1 signaling.

Tumors initiate by mutations in cancer cells, and progress through interactions of the cancer cells with non-malignant cells of the tumor microenvironment. Major players in the tumor microenvironment are cancer-associated fibroblasts (CAFs), which support tumor malignancy, and comprise up to 90% of the tumor mass in pancreatic cancer. CAFs are transcriptionally rewired by cancer cells. Whether this rewiring is differentially affected by different mutations in cancer cells is largely unknown. Here we address this question by dissecting the stromal landscape of BRCA-mutated and BRCA Wild-type pancreatic ductal adenocarcinoma. We comprehensively analyze pancreatic cancer samples from 42 patients, revealing different CAF subtype compositions in germline BRCA-mutated vs. BRCA Wild-type tumors. In particular, we detect an increase in a subset of immune-regulatory clusterin-positive CAFs in BRCA-mutated tumors. Using cancer organoids and mouse models we show that this process is mediated through activation of heat-shock factor 1, the transcriptional regulator of clusterin. Our findings unravel a dimension of stromal heterogeneity influenced by germline mutations in cancer cells, with direct implications for clinical research.

Identification of Small Molecules with Improved Potency against Orthopoxviruses from Vaccinia to Smallpox.

The genus Orthopoxvirus contains several human pathogens, including vaccinia, monkeypox, cowpox, and variola virus, the causative agent of smallpox. Although there are a few effective vaccines, widespread prophylactic vaccination has ceased and is unlikely to resume, making therapeutics increasingly important to treat poxvirus disease. Here, we described efforts to improve the potency of the anti-poxvirus small molecule CMLDBU6128. This class of small molecules, referred to as pyridopyrimidinones (PDPMs), showed a wide range of biological activities. Through the synthesis and testing of several exploratory chemical libraries based on this molecule, we identified several compounds that had increased potency from the micromolar into the nanomolar range. Two compounds, designated (12) and (16), showed inhibitory concentrations of 326 nM and 101 nM, respectively, which was more than a 10-fold increase in potency to CMLDBU6128 with an inhibitory concentration of around 6 µM. We also expanded our investigation of the breadth of action of these molecules and showed that they can inhibit the replication of variola virus, a related orthopoxvirus. Together, these findings highlighted the promise of this new class of antipoxviral agents as broad-spectrum small molecules with significant potential to be developed as antiviral therapy. This would add a small molecule option for therapy of spreading diseases, including monkeypox and cowpox viruses, that would also be expected to have efficacy against smallpox.

Neighborhood cohesion and psychological distress across race and sexual orientation.

Introduction: We investigate the association neighborhood cohesion, as source of social support, has with psychological distress among white, Black, and Latinx lesbian, gay, and bisexual (LGB) individuals, compared to heterosexual individuals in the United States. Method: We estimate zero-order multinomial logistic regression models to assess the likelihood of moderate and severe psychological distress among respondents. Result: In the models accounting for neighborhood cohesion and all other covariates, white, Black, and Latinx lesbian, gay, and bisexual individuals are more likely to meet the criteria for moderate and severe psychological distress than non-LGB people. Conclusion: Neighborhood cohesion has differing impact on psychological distress outcomes by racial/ethnic-sexual orientation groups, but in general provides a greater magnitude of protection against moderate psychological distress for non-LGB groups and a greater magnitude of protection against severe psychological distress for LGB groups.

Inhibition of the Translation Initiation Factor eIF4A Enhances Tumor Cell Radiosensitivity.

A fundamental component of cellular radioresponse is the translational control of gene expression. Because a critical regulator of translational control is the eukaryotic translation initiation factor 4F (eIF4F) cap binding complex, we investigated whether eIF4A, the RNA helicase component of eIF4F, can serve as a target for radiosensitization. Knockdown of eIF4A using siRNA reduced translational efficiency, as determined from polysome profiles, and enhanced tumor cell radiosensitivity as determined by clonogenic survival. The increased radiosensitivity was accompanied by a delayed dispersion of radiation-induced γH2AX foci, suggestive of an inhibition of DNA double-strand break repair. Studies were then extended to (-)-SDS-1-021, a pharmacologic inhibitor of eIF4A. Treatment of cells with the rocaglate (-)-SDS-1-021 resulted in a decrease in translational efficiency as well as protein synthesis. (-)-SDS-1-021 treatment also enhanced the radiosensitivity of tumor cell lines. This (-)-SDS-1-021-induced radiosensitization was accompanied by a delay in radiation-induced γH2AX foci dispersal, consistent with a causative role for the inhibition of double-strand break repair. In contrast, although (-)-SDS-1-021 inhibited translation and protein synthesis in a normal fibroblast cell line, it had no effect on radiosensitivity of normal cells. Subcutaneous xenografts were then used to evaluate the in vivo response to (-)-SDS-1-021 and radiation. Treatment of mice bearing subcutaneous xenografts with (-)-SDS-1-021 decreased tumor translational efficiency as determined by polysome profiles. Although (-)-SDS-1-021 treatment alone had no effect on tumor growth, it significantly enhanced the radiation-induced growth delay. These results suggest that eIF4A is a tumor-selective target for radiosensitization.

Identification of structurally re-engineered rocaglates as inhibitors against hepatitis E virus replication.

Hepatitis E virus (HEV) infections are a leading cause of acute viral hepatitis in humans and pose a considerable threat to public health. Current standard of care treatment is limited to the off-label use of nucleoside-analog ribavirin (RBV) and PEGylated interferon-α, both of which are associated with significant side effects and provide limited efficacy. In the past few years, a promising natural product compound class of eukaryotic initiation factor 4A (eIF4A) inhibitors (translation initiation inhibitors), called rocaglates, were identified as antiviral agents against RNA virus infections. In the present study, we evaluated a total of 205 synthetic rocaglate derivatives from the BU-CMD compound library for their antiviral properties against HEV. At least eleven compounds showed inhibitory activities against the HEV genotype 3 (HEV-3) subgenomic replicon below 30 nM (EC50 value) as determined by Gaussia luciferase assay. Three amidino-rocaglates (ADRs) (CMLD012073, CMLD012118, and CMLD012612) possessed antiviral activity against HEV with EC50 values between 1 and 9 nM. In addition, these three selected compounds inhibited subgenomic replicons of different genotypes (HEV-1 [Sar55], wild boar HEV-3 [83-2] and human HEV-3 [p6]) in a dose-dependent manner and at low nanomolar concentrations. Furthermore, tested ADRs tend to be better tolerated in primary hepatocytes than hepatoma cancer cell lines and combination treatment of CMLD012118 with RBV and interferon-α (IFN-α) showed that CMLD012118 acts additive to RBV and IFN-α treatment. In conclusion, our results indicate that ADRs, especially CMLD012073, CMLD012118, and CMLD012612 may prove to be potential therapeutic candidates for the treatment of HEV infections and may contribute to the discovery of pan-genotypic inhibitors in the future.

Divergent, C-C Bond Forming Macrocyclizations Using Modular Sulfonylhydrazone and Derived Substrates.

A divergent approach to C-C bond forming macrocycle construction is described. Modular sulfonylhydrazone and derived pyridotriazole substrates with three key building blocks have been constructed and cyclized to afford diverse macrocyclic frameworks. Broad substrate scope and functional group tolerance have been demonstrated. In addition, site-selective postfunctionalization allowed for further diversification of macrocyclic cores.

Condensation tendency and planar isotropic actin gradient induce radial alignment in confined monolayers.

A monolayer of highly motile cells can establish long-range orientational order, which can be explained by hydrodynamic theory of active gels and fluids. However, it is less clear how cell shape changes and rearrangement are governed when the monolayer is in mechanical equilibrium states when cell motility diminishes. In this work, we report that rat embryonic fibroblasts (REF), when confined in circular mesoscale patterns on rigid substrates, can transition from the spindle shapes to more compact morphologies. Cells align radially only at the pattern boundary when they are in the mechanical equilibrium. This radial alignment disappears when cell contractility or cell-cell adhesion is reduced. Unlike monolayers of spindle-like cells such as NIH-3T3 fibroblasts with minimal intercellular interactions or epithelial cells like Madin-Darby canine kidney (MDCK) with strong cortical actin network, confined REF monolayers present an actin gradient with isotropic meshwork, suggesting the existence of a stiffness gradient. In addition, the REF cells tend to condense on soft substrates, a collective cell behavior we refer to as the 'condensation tendency'. This condensation tendency, together with geometrical confinement, induces tensile prestretch (i.e. an isotropic stretch that causes tissue to contract when released) to the confined monolayer. By developing a Voronoi-cell model, we demonstrate that the combined global tissue prestretch and cell stiffness differential between the inner and boundary cells can sufficiently define the cell radial alignment at the pattern boundary.

Channeling macrophage polarization by rocaglates increases macrophage resistance to Mycobacterium tuberculosis.

Macrophages contribute to host immunity and tissue homeostasis via alternative activation programs. M1-like macrophages control intracellular bacterial pathogens and tumor progression. In contrast, M2-like macrophages shape reparative microenvironments that can be conducive for pathogen survival or tumor growth. An imbalance of these macrophages phenotypes may perpetuate sites of chronic unresolved inflammation, such as infectious granulomas and solid tumors. We have found that plant-derived and synthetic rocaglates sensitize macrophages to low concentrations of the M1-inducing cytokine IFN-gamma and inhibit their responsiveness to IL-4, a prototypical activator of the M2-like phenotype. Treatment of primary macrophages with rocaglates enhanced phagosome-lysosome fusion and control of intracellular mycobacteria. Thus, rocaglates represent a novel class of immunomodulators that can direct macrophage polarization toward the M1-like phenotype in complex microenvironments associated with hypofunction of type 1 and/or hyperactivation of type 2 immunity, e.g., chronic bacterial infections, allergies, and, possibly, certain tumors.

Socioeconomic Disadvantage and Distance to Pediatric Critical Care.

OBJECTIVES: To describe the geography of pediatric critical care services and the relationship between poverty and distance to these services across the United States. DESIGN: Retrospective, cross-sectional study. SETTING: Contiguous United States. PATIENTS: Children less than 18 years as represented in the 2016 American Community Survey. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Pediatric critical care services were geographically concentrated within urban areas, with half of all PICUs located within 9.5 miles of another (interquartile range, 3.4-51.5 miles). Median distances from neighborhoods to the nearest unit increased linearly with Area Deprivation Index (p < 0.001), such that the median distance from the least privileged neighborhoods was nearly three times that of the most privileged neighborhoods (first decile = 7.8 miles [interquartile range, 3.4-15.8 miles] vs tenth decile = 22.6 miles [interquartile range, 4.2-52.5 miles]; p < 0.001). A relationship between neighborhood poverty and distance to a PICU was present across all U.S. regions and within urban/suburban and rural areas. CONCLUSIONS: In the United States, the distance to pediatric critical care services increases with poverty. This carries implications for access to care and health outcome disparities.

Defining and navigating macrocycle chemical space.

Macrocyclic compounds (MCs) are of growing interest for inhibition of challenging drug targets. We consider afresh what structural and physicochemical features could be relevant to the bioactivity of this compound class. Using these features, we performed Principal Component Analysis to map oral and non-oral macrocycle drugs and clinical candidates, and also commercially available synthetic MCs, in structure-property space. We find that oral MC drugs occupy defined regions that are distinct from those of the non-oral MC drugs. None of the oral MC regions are effectively sampled by the synthetic MCs. We identify 13 properties that can be used to design synthetic MCs that sample regions overlapping with oral MC drugs. The results advance our understanding of what molecular features are associated with bioactive and orally bioavailable MCs, and illustrate an approach by which synthetic chemists can better evaluate MC designs. We also identify underexplored regions of macrocycle chemical space.

Fungal-Selective Resorcylate Aminopyrazole Hsp90 Inhibitors: Optimization of Whole-Cell Anticryptococcal Activity and Insights into the Structural Origins of Cryptococcal Selectivity.

The essential eukaryotic chaperone Hsp90 regulates the form and function of diverse client proteins, many of which govern thermotolerance, virulence, and drug resistance in fungal species. However, use of Hsp90 inhibitors as antifungal therapeutics has been precluded by human host toxicities and suppression of immune responses. We recently described resorcylate aminopyrazoles (RAPs) as the first class of Hsp90 inhibitors capable of discriminating between fungal (Cryptococcus neoformans, Candida albicans) and human isoforms of Hsp90 in biochemical assays. Here, we report an iterative structure-property optimization toward RAPs capable of inhibiting C. neoformans growth in culture. In addition, we report the first X-ray crystal structures of C. neoformans Hsp90 nucleotide binding domain (NBD), as the apoprotein and in complexes with the non-species-selective Hsp90 inhibitor NVP-AUY922 and three RAPs revealing unique ligand-induced conformational rearrangements, which reaffirm the hypothesis that intrinsic differences in protein flexibility can confer selective inhibition of fungal versus human Hsp90 isoforms.

Sources of 2,3,7,8-Tetrachlorodibenzo-p-dioxin and Other Dioxins in Lower Passaic River, New Jersey, Sediments.

Elevated levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and other contaminants have been reported in lower Passaic River, New Jersey, USA, sediments since the 1980s. Nearly 8000 surficial and buried sediment samples have been collected along the 17 miles (27.4 km) of river and analyzed for various contaminants, including the seventeen 2,3,7,8-substituted PCDD/F congeners. Principal component analysis and hierarchical cluster analysis reveal spatial heterogeneity in the distribution of dioxin congeners, with respect to both sediment depth and river mile. Polytopic vector analysis resolved 11 unique 2,3,7,8-substituted dioxin congener profiles in the river sediment. The profiles were consistent with multiple dioxin source types, including manufacture of certain dyes and pigments, chlorinated industrial chemicals, hexachlorophene, polychlorinated biphenyls, waste disposal and incineration, the production and use of 2,4,5-trichorophenol (2,4,5-TCP), and other industrial processes. The distribution of dioxin profiles in surface and buried river sediments is indicative of multiple inputs of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and other dioxins at different locations along the lower Passaic River. These findings are inconsistent with historical claims that a former herbicide manufacturing plant in the lower reach of the river is the only significant 2,3,7,8-TCDD source and consistent with evidence of several different inputs associated with the production, use, and/or disposal of 2,4,5-TCP at several locations along the lower Passaic River. Environ Toxicol Chem 2021;40:1499-1519. © 2020 SETAC.

An oxindole efflux inhibitor potentiates azoles and impairs virulence in the fungal pathogen Candida auris.

Candida auris is an emerging fungal pathogen that exhibits resistance to multiple drugs, including the most commonly prescribed antifungal, fluconazole. Here, we use a combinatorial screening approach to identify a bis-benzodioxolylindolinone (azoffluxin) that synergizes with fluconazole against C. auris. Azoffluxin enhances fluconazole activity through the inhibition of efflux pump Cdr1, thus increasing intracellular fluconazole levels. This activity is conserved across most C. auris clades, with the exception of clade III. Azoffluxin also inhibits efflux in highly azole-resistant strains of Candida albicans, another human fungal pathogen, increasing their susceptibility to fluconazole. Furthermore, azoffluxin enhances fluconazole activity in mice infected with C. auris, reducing fungal burden. Our findings suggest that pharmacologically targeting Cdr1 in combination with azoles may be an effective strategy to control infection caused by azole-resistant isolates of C. auris.