Highly specific intracellular ubiquitination of a small molecule

Ubiquitin is a small, highly conserved protein that acts as a posttranslational modification in eukaryotes. Ubiquitination of proteins frequently serves as a degradation signal, marking them for disposal by the proteasome. Here, we report a novel small molecule from a diversity-oriented synthesis library, BRD1732, that is directly ubiquitinated in cells, resulting in dramatic accumulation of inactive ubiquitin monomers and polyubiquitin chains causing broad inhibition of the ubiquitin-proteasome system. Ubiquitination of BRD1732 and its associated cytotoxicity are stereospecific and dependent upon two homologous E3 ubiquitin ligases, RNF19A and RNF19B. Our finding opens the possibility for indirect ubiquitination of a target through a ubiquitinated bifunctional small molecule, and more broadly raises the potential for posttranslational modification in trans .

Diversity-oriented synthesis encoded by deoxyoligonucleotides

Diversity-oriented synthesis (DOS) is a powerful strategy to prepare molecules with underrepresented features in commercial screening collections, resulting in the elucidation of novel biological mechanisms. In parallel to the development of DOS, DNA-encoded libraries (DELs) have emerged as an effective, efficient screening strategy to identify protein binders. Despite recent advancements in this field, most DEL syntheses are limited by the presence of sensitive DNA-based constructs. Here, we describe the design, synthesis, and validation experiments performed for a 3.7 million-member DEL, generated using diverse skeleton architectures with varying exit vectors and derived from DOS, to achieve structural diversity beyond what is possible by varying appendages alone. We also show screening results for three diverse protein targets. We will make this DEL available to the academic scientific community to increase access to novel structural features and accelerate early-phase drug discovery.

Identification of inhibitors against interaction between pro-inflammatory sPLA2-IIA protein and integrin αvβ3

Increased concentrations of secreted phospholipase A2 type IIA (sPLA2-IIA), have been found in the synovial fluid of patients with rheumatoid arthritis. It has been shown that sPLA2-IIA specifically binds to integrin αvβ3, and initiates a signaling pathway that leads to cell proliferation and inflammation. Therefore, the interaction between integrin and sPLA2-IIA could be a potential therapeutic target for the treatment of proliferation or inflammation-related diseases. Two one-bead-one-compound peptide libraries were constructed and screened, and seven target hits were identified. Herein we report the identification, synthesis, and biological testing of two pyrazolylthiazole-tethered peptide hits and their analogs. Biological assays showed that these compounds were able to suppress the sPLA2-IIA-integrin interaction and sPLA2-IIA-induced migration of monocytic cells and that the blockade of the sPLA2-IIA-integrin binding was specific to sPLA2-IIA and not to the integrin.

Multicomponent assembly of highly substituted indoles by dual palladium-catalyzed coupling reactions

Highly substituted indoles were synthesized by a palladium-catalyzed reaction involving three independent components in a one-pot reaction. Two distinct palladium-catalyzed coupling reactions occur with a single catalytic system: a Buchwald-Hartwig reaction and an arene-alkene coupling. Quantum chemical computations provide insight into the mechanism of the latter coupling step.

Expedient synthesis of a 72-membered isoxazolino-β-ketoamide library by a 2·3-component reaction

An efficient 2·3-component reaction (2·3CR; a 2-component reaction followed, in one pot, by a3-component reaction) is presented for the synthesis of isoxazolino-β-ketoamides. This 2·3CR proceeds by (i) a Meldrum's acid-generated acyl ketene, which is trapped by an amine to form a β-ketoamide intermediate in a 2CR followed, in one pot, by (ii) a Mannich reaction followed by elimination of dimethyl amine·HCl to generate an α,β-unsaturated β-ketoamide dipolarophile that reacts in a nitrile oxide 1,3-dipolar cycloaddition reaction. This one-pot 2·3CR process delivers the targeted isoxazolino-β-ketoamide product. A total of 72 compounds are presented, all of which have been submitted to the NIH Molecular Libraries Small Molecule Repository for high-throughput biological screening.

Structure-activity relationships of cyanoquinolines with corrector-potentiator activity in ΔF508 cystic fibrosis transmembrane conductance regulator protein

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. The most common CF-causing mutation, ΔF508-CFTR, produces CFTR loss-of-function by impairing its cellular targeting to the plasma membrane and its chloride channel gating. We recently identified cyanoquinolines with both corrector ("Co", normalizing ΔF508-CFTR targeting) and potentiator ("Po", normalizing ΔF508-CFTR channel gating) activities. Here, we synthesized and characterized 24 targeted cyanoquinoline analogues to elucidate the conformational requirements for corrector and potentiator activities. Compounds with potentiator-only, corrector-only, and dual potentiator-corrector activities were found. Molecular modeling studies (conformational search ⇒ force-field lowest energy assessment ⇒ geometry optimization) suggest that (1) a flexible tether and (2) a relatively short bridge between the cyanoquinoline and arylamide moieties are important cyanoquinoline-based CoPo features. Further, these CoPo's may adopt two distinct π-stacking conformations to elicit corrector and potentiator activities.

Multicomponent macrocyclization reactions (MCMRs) employing highly reactive acyl ketene and nitrile oxide intermediates

An efficient synthesis of spiro-fused macrolactams by a multicomponent macrocyclization reaction (MCMR) is reported. The use of highly reactive, transient intermediates in this MCMR permits short reaction times, even at high dilution. The methods employed for this MCMR were first developed as a four-component strategy for the synthesis of β-ketoamide isoxazolines and a new macrocyclization reaction is reported.

Cyanoquinolines with independent corrector and potentiator activities restore ΔPhe508-cystic fibrosis transmembrane conductance regulator chloride channel function in cystic fibrosis

The ΔPhe508 mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) protein impairs its folding, stability, and chloride channel gating. Although small molecules that separately correct defective ΔPhe508-CFTR folding/cellular processing ("correctors") or chloride channel gating ("potentiators") have been discovered and are in clinical trials, single compounds with bona fide dual corrector and potentiator activities have not been identified. Here, screening of ∼110,000 small molecules not tested previously revealed a cyanoquinoline class of compounds with independent corrector and potentiator activities (termed CoPo). Analysis of 180 CoPo analogs revealed 6 compounds with dual corrector and potentiator activities and 13 compounds with only potentiator activity. N-(2-((3-Cyano-5,7-dimethylquinolin-2-yl)amino)ethyl)-3-methoxybenzamide (CoPo-22), which was synthesized in six steps in 52% overall yield, had low micromolar EC(50) for ΔPhe508-CFTR corrector and potentiator activities by short-circuit current assay. Maximal corrector and potentiator activities were comparable with those conferred by the bithiazole Corr-4a and the flavone genistein, respectively. CoPo-22 also activated wild-type and G551D CFTR chloride conductance within minutes in a forskolin-dependent manner. Compounds with dual corrector and potentiator activities may be useful for single-drug treatment of cystic fibrosis caused by ΔPhe508 mutation.

Pyrazolylthiazole as DeltaF508-cystic fibrosis transmembrane conductance regulator correctors with improved hydrophilicity compared to bithiazoles

Deletion of phenylalanine residue 508 (DeltaF508) in the cystic fibrosis (CF) transmembrane conductance regulator protein (CFTR) is a major cause of CF. Small molecule "correctors" of defective DeltaF508-CFTR cellular processing hold promise for CF therapy. We previously identified and characterized bithiazole CF corrector 1 and s-cis-locked bithiazole 2. Herein, we report the regiodivergent synthesis of Ngamma and Nbeta isomers of thiazole-tethered pyrazoles with improved hydrophilicity compared to bithiazoles. We synthesized a focused library of 54 pyrazolylthiazoles 3, which included examples of both regioisomers 4 and 5. The thiazole-tethered pyrazoles allowed incorporation of property-modulating functionality on the pyrazole ring (ester, acid, and amide) while retaining DeltaF508-CFTR corrector activity (EC(50)) of under 1 microM. The most active pyrazolylthiazole (14h) has an experimentally determined log P of 4.1, which is 1.2 log units lower than bithiazole CF corrector 1.

Determinants of compliance with a national smoke-free hospital standard

OBJECTIVE

To determine the extent of compliance with the new Joint Commission on Accreditation of Healthcare Organizations (JCAHO) standard requiring acute care hospitals to be smoke-free, and to identify predictors of adoption of smoke-free hospital policies.

DESIGN

We conducted a survey of a national sample of acute care hospitals and developed a predictive model for implementation of smoke-free policies during multiple logistic regression. We examined numerous factors that might predict adoption of smoke-free policies, such as hospital characteristics, patient care services, and experience with smoke-free initiatives.

SETTING AND PARTICIPANTS

A systematic 20% sample of JCAHO-accredited hospitals in the United States (n = 1278). Military, Department of Veterans Affairs, Indian Health Service, psychiatric, substance abuse treatment, and children's hospitals were excluded.

MAIN OUTCOME MEASURE

Compliance with the JCAHO standard.

RESULTS

The response rate was 85%. Six-five percent of hospitals were in compliance with the standard 16 months after it was introduced. Factors that were independently and positively associated with implementation of smoke-free policies were administrative support (odds ratio [OR], 7.82; 95% confidence interval [Cl], 2.05 to 29.65) and inpatient smoking cessation services (OR, 1.24; 95% Cl, 1.02 to 1.52). Factors negatively associated with implementation of smoke-free policy were the number of psychiatric treatment beds (OR, 0.57; 95% Cl, 0.14 to 0.81), number of substance abuse treatment beds (OR, 0.17; 95% Cl, 0.11 to 0.26), and presence of an active task force to address smoking policy (OR, 0.56; 95% Cl, 0.40 to 0.77).

CONCLUSIONS

The majority of acute care hospitals are in compliance with the JCAHO national smoke-free policy initiative. The standard is well accepted by most patients and employees. It is critical to address the challenges presented by special populations, such as psychiatry patients, to accomplish the goal of completely smoke-free hospitals.

Managing tobacco dependence in chemical dependency treatment facilities: a survey of current attitudes and policies

This paper presents survey results of Minnesota licensed chemical dependency treatment facility directors. The baseline survey was conducted by telephone in May and June of 1988; and the self-administered follow-up survey was conducted in February and March of 1990, subsequent to a statewide tobacco dependence educational campaign which targeted Minnesota's chemical dependency professionals. Both the baseline (n = 227) and the follow-up (n = 257) surveys contained items concerning the directors' beliefs about the health effects of tobacco use, their attitudes regarding tobacco use in chemical dependency treatment, current tobacco policy in the facility, and barriers to banning tobacco use in the facility. The study used a matched-pair analysis (n = 104) of the survey data to assess changes in attitudes and practices during the two years of the study. The majority (71%) of chemical dependency directors at follow-up agree that tobacco dependence should be treated like other drug dependencies. The percentage of matched facilities that treat tobacco dependence increased from 10% at baseline to 18% at follow-up. The percentage of facilities that prohibit smoking increased from 11% at baseline to 27% at follow-up. Implications of the findings and areas for further research are discussed.

A controlled trial to implement smoke-free hospitals

Hospitals would logically become leaders if the nation is to accept former Surgeon General C. Everett Koop's challenge to make its public institutions smoke-free by the year 2000. We tested whether printed materials, workshops, newsletters, and consultations could increase both the number of smoke-free hospitals in a state and the rate at which they became smoke-free. All acute-care hospitals in Minnesota (n = 166) were compared to a sample of 51 acute-care hospitals in a reference area, western Wisconsin, before and after a one-year campaign. While 2.4% of the hospitals in Minnesota were smoke-free before the campaign, none of the hospitals in the reference area sample was smoke-free at this time. Both areas experienced a significant increase in the proportion of hospitals that became smoke-free during the year--30.7% of the Minnesota hospitals and 15.7% of the hospitals in the reference area sample (p less than .01) were smoke-free after the one-year campaign--and the campaign did appear to marginally increase the rate of adoption in Minnesota over that of the reference area (p = .08). The results of this study indicate that smoke-free hospitals are feasible and that a statewide initiative can facilitate the hospitals' decision to become smoke-free.