Publications by authors named "Richard Trilles"

11 Publications

  • Page 1 of 1

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

J Med Chem 2021 01 14;64(2):1139-1169. Epub 2021 Jan 14.

Department of Chemistry and Center for Molecular Discovery (BU-CMD), Boston University, Boston, Massachusetts 02215, United States.

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 (, ) and human isoforms of Hsp90 in biochemical assays. Here, we report an iterative structure-property optimization toward RAPs capable of inhibiting growth in culture. In addition, we report the first X-ray crystal structures of 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.
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http://dx.doi.org/10.1021/acs.jmedchem.0c01777DOI Listing
January 2021

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

Nat Commun 2020 12 22;11(1):6429. Epub 2020 Dec 22.

Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.

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.
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http://dx.doi.org/10.1038/s41467-020-20183-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7755909PMC
December 2020

Structural basis for species-selective targeting of Hsp90 in a pathogenic fungus.

Nat Commun 2019 01 24;10(1):402. Epub 2019 Jan 24.

Department of Molecular Genetics, University of Toronto, Toronto, ON, M5G 1M1, Canada.

New strategies are needed to counter the escalating threat posed by drug-resistant fungi. The molecular chaperone Hsp90 affords a promising target because it supports survival, virulence and drug-resistance across diverse pathogens. Inhibitors of human Hsp90 under development as anticancer therapeutics, however, exert host toxicities that preclude their use as antifungals. Seeking a route to species-selectivity, we investigate the nucleotide-binding domain (NBD) of Hsp90 from the most common human fungal pathogen, Candida albicans. Here we report structures for this NBD alone, in complex with ADP or in complex with known Hsp90 inhibitors. Encouraged by the conformational flexibility revealed by these structures, we synthesize an inhibitor with >25-fold binding-selectivity for fungal Hsp90 NBD. Comparing co-crystals occupied by this probe vs. anticancer Hsp90 inhibitors revealed major, previously unreported conformational rearrangements. These insights and our probe's species-selectivity in culture support the feasibility of targeting Hsp90 as a promising antifungal strategy.
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http://dx.doi.org/10.1038/s41467-018-08248-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6345968PMC
January 2019

Discovery of Macrocyclic Inhibitors of Apurinic/Apyrimidinic Endonuclease 1.

J Med Chem 2019 02 6;62(4):1971-1988. Epub 2019 Feb 6.

Department of Chemistry and Chemical Biology, Purdue School of Science , Indiana University-Purdue University Indianapolis , Indianapolis , Indiana 46202 , United States.

Apurinic/apyrimidinic endonuclease 1 (APE1) is an essential base excision repair enzyme that is upregulated in a number of cancers, contributes to resistance of tumors treated with DNA-alkylating or -oxidizing agents, and has recently been identified as an important therapeutic target. In this work, we identified hot spots for binding of small organic molecules experimentally in high resolution crystal structures of APE1 and computationally through the use of FTMAP analysis ( http://ftmap.bu.edu/ ). Guided by these hot spots, a library of drug-like macrocycles was docked and then screened for inhibition of APE1 endonuclease activity. In an iterative process, hot-spot-guided docking, characterization of inhibition of APE1 endonuclease, and cytotoxicity of cancer cells were used to design next generation macrocycles. To assess target selectivity in cells, selected macrocycles were analyzed for modulation of DNA damage. Taken together, our studies suggest that macrocycles represent a promising class of compounds for inhibition of APE1 in cancer cells.
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http://dx.doi.org/10.1021/acs.jmedchem.8b01529DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6583781PMC
February 2019

High-throughput Screening in Larval Zebrafish Identifies Novel Potent Sedative-hypnotics.

Anesthesiology 2018 09;129(3):459-476

From the Department of Anesthesiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China (X.Y., B.Y.) the Department of Anesthesia, Critical Care and Pain Medicine (X.Y., Y.J., J.B.D., F.M.-O., E.S.H., S.A.F.) the Center for Regenerative Medicine (R.D.) Massachusetts General Hospital, Boston, Massachusetts; and the Department of Chemistry and Center for Molecular Discovery, Boston University, Boston, Massachusetts (L.E.B., R.T., W.X., S.E.S., J.A.P.).

What We Already Know About This Topic: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Many general anesthetics were discovered empirically, but primary screens to find new sedative-hypnotics in drug libraries have not used animals, limiting the types of drugs discovered. The authors hypothesized that a sedative-hypnotic screening approach using zebrafish larvae responses to sensory stimuli would perform comparably to standard assays, and efficiently identify new active compounds.

Methods: The authors developed a binary outcome photomotor response assay for zebrafish larvae using a computerized system that tracked individual motions of up to 96 animals simultaneously. The assay was validated against tadpole loss of righting reflexes, using sedative-hypnotics of widely varying potencies that affect various molecular targets. A total of 374 representative compounds from a larger library were screened in zebrafish larvae for hypnotic activity at 10 µM. Molecular mechanisms of hits were explored in anesthetic-sensitive ion channels using electrophysiology, or in zebrafish using a specific reversal agent.

Results: Zebrafish larvae assays required far less drug, time, and effort than tadpoles. In validation experiments, zebrafish and tadpole screening for hypnotic activity agreed 100% (n = 11; P = 0.002), and potencies were very similar (Pearson correlation, r > 0.999). Two reversible and potent sedative-hypnotics were discovered in the library subset. CMLD003237 (EC50, ~11 µM) weakly modulated γ-aminobutyric acid type A receptors and inhibited neuronal nicotinic receptors. CMLD006025 (EC50, ~13 µM) inhibited both N-methyl-D-aspartate and neuronal nicotinic receptors.

Conclusions: Photomotor response assays in zebrafish larvae are a mechanism-independent platform for high-throughput screening to identify novel sedative-hypnotics. The variety of chemotypes producing hypnosis is likely much larger than currently known.
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http://dx.doi.org/10.1097/ALN.0000000000002281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6092221PMC
September 2018

Dihydropyrimidine-Thiones and Clioquinol Synergize To Target β-Amyloid Cellular Pathologies through a Metal-Dependent Mechanism.

ACS Chem Neurosci 2017 09 12;8(9):2039-2055. Epub 2017 Jul 12.

Whitehead Institute for Biomedical Research , Cambridge, Massachusetts 02142, United States.

The lack of therapies for neurodegenerative diseases arises from our incomplete understanding of their underlying cellular toxicities and the limited number of predictive model systems. It is critical that we develop approaches to identify novel targets and lead compounds. Here, a phenotypic screen of yeast proteinopathy models identified dihydropyrimidine-thiones (DHPM-thiones) that selectively rescued the toxicity caused by β-amyloid (Aβ), the peptide implicated in Alzheimer's disease. Rescue of Aβ toxicity by DHPM-thiones occurred through a metal-dependent mechanism of action. The bioactivity was distinct, however, from that of the 8-hydroxyquinoline clioquinol (CQ). These structurally dissimilar compounds strongly synergized at concentrations otherwise not competent to reduce toxicity. Cotreatment ameliorated Aβ toxicity by reducing Aβ levels and restoring functional vesicle trafficking. Notably, these low doses significantly reduced deleterious off-target effects caused by CQ on mitochondria at higher concentrations. Both single and combinatorial treatments also reduced death of neurons expressing Aβ in a nematode, indicating that DHPM-thiones target a conserved protective mechanism. Furthermore, this conserved activity suggests that expression of the Aβ peptide causes similar cellular pathologies from yeast to neurons. Our identification of a new cytoprotective scaffold that requires metal-binding underscores the critical role of metal phenomenology in mediating Aβ toxicity. Additionally, our findings demonstrate the valuable potential of synergistic compounds to enhance on-target activities, while mitigating deleterious off-target effects. The identification and prosecution of synergistic compounds could prove useful for developing AD therapeutics where combination therapies may be required to antagonize diverse pathologies.
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http://dx.doi.org/10.1021/acschemneuro.7b00187DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5705239PMC
September 2017

Discovery of new piperidine amide triazolobenzodiazepinones as intestinal-selective CCK1 receptor agonists.

Bioorg Med Chem Lett 2012 Apr 23;22(8):2943-7. Epub 2012 Feb 23.

Department of Cardiovascular, Metabolic, and Endocrine Diseases, Pfizer Global Research and Development, Groton, CT 06340, USA.

New cholecystokinin-1 receptor (CCK1R) agonist 'triggers' were identified using iterative library synthesis. Structural activity relationship studies led to the discovery of compound 10e, a potent CCK1R agonist that demonstrated robust weight loss in a diet-induced obese rat model with very low systemic exposure. Pharmacokinetic data suggest that efficacy is primarily driven through activation of CCK1R's located within the intestinal wall.
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http://dx.doi.org/10.1016/j.bmcl.2012.02.049DOI Listing
April 2012

Discovery of new antimalarial chemotypes through chemical methodology and library development.

Proc Natl Acad Sci U S A 2011 Apr 15;108(17):6775-80. Epub 2011 Apr 15.

Department of Chemistry and Center for Chemical Methodology and Library Development, Boston University, 590 Commonwealth Avenue, Boston, MA 02215.

In an effort to expand the stereochemical and structural complexity of chemical libraries used in drug discovery, the Center for Chemical Methodology and Library Development at Boston University has established an infrastructure to translate methodologies accessing diverse chemotypes into arrayed libraries for biological evaluation. In a collaborative effort, the NIH Chemical Genomics Center determined IC(50)'s for Plasmodium falciparum viability for each of 2,070 members of the CMLD-BU compound collection using quantitative high-throughput screening across five parasite lines of distinct geographic origin. Three compound classes displaying either differential or comprehensive antimalarial activity across the lines were identified, and the nascent structure activity relationships (SAR) from this experiment used to initiate optimization of these chemotypes for further development.
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http://dx.doi.org/10.1073/pnas.1017666108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3084078PMC
April 2011

N-benzylimidazole carboxamides as potent, orally active stearoylCoA desaturase-1 inhibitors.

Bioorg Med Chem Lett 2011 Mar 31;21(6):1621-5. Epub 2011 Jan 31.

Pfizer Global Research & Development, Groton Laboratories, Pfizer Inc., Groton, CT 06340, USA.

A potent, small molecule inhibitor with a favorable pharmacokinetic profile to allow for sustained SCD inhibition in vivo was identified. Starting from a low MW acyl guanidine (5a), identified with a RapidFire High-Throughput Mass Spectrometry (RF-MS) assay, iterative library design was used to rapidly probe the amide and tail regions of the molecule. Singleton synthesis was used to probe core changes. Biological evaluation of a SCD inhibitor (5b) included in vitro potency at SCD-1 and in vivo modulation of the plasma desaturation index (DI) in rats on a low essential fatty acid (LEFA) diet. In addition to dose-dependent decrease in DI, effects on rodent ocular tissue were noted. Therefore, in rat, these SCD inhibitors only recapitulate a portion of phenotype exhibited by the SCD-1 knockout mouse.
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http://dx.doi.org/10.1016/j.bmcl.2011.01.113DOI Listing
March 2011

Focused library approach for identification of new N-acylphenylalanines as VCAM/VLA-4 antagonists.

Bioorg Med Chem Lett 2002 Jun;12(12):1679-82

Roche Research Center, Hoffmann-La Roche Inc., 340 Kingsland Street, Nutley, NJ 07110, USA.

A structure-based focused library approach was employed in an effort to identify more lipophilic replacements for the N-benzylpyroglutamyl group of the VCAM/VLA-4 antagonist 2. This effort led to the discovery of two new classes of potent antagonists characterized by the N-(alpha-phenylcyclopentanoyl- and the N-(2,6-dimethylbenzoyl)-derivatives 60 and 64.
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http://dx.doi.org/10.1016/s0960-894x(02)00201-9DOI Listing
June 2002

N-acyl-L-phenylalanine derivatives as potent VLA-4 antagonists that mimic a cyclic peptide conformation.

Bioorg Med Chem Lett 2002 Jan;12(2):137-40

Roche Research Center, Hoffmann-La Roche Inc, Nutley, NJ 07110, USA.

A series of N-benzylpyroglutamyl-L-phenylalanine derivatives bearing carbamoyl substituents in the 3- or 4-positions was prepared and assayed for inhibition of the interaction between VCAM and VLA-4. Potent inhibition was observed in a number of analogues with substitution in the 4-position favored over the 3-position. A crystal structure of the key intermediate 25 indicates that it accesses a low energy conformation which closely matches key pharmacophores of a structurally characterized cyclic peptide.
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http://dx.doi.org/10.1016/s0960-894x(01)00711-9DOI Listing
January 2002