An artificial intelligence accelerated virtual screening platform for drug discovery.

Structure-based virtual screening is a key tool in early drug discovery, with growing interest in the screening of multi-billion chemical compound libraries. However, the success of virtual screening crucially depends on the accuracy of the binding pose and binding affinity predicted by computational docking. Here we develop a highly accurate structure-based virtual screen method, RosettaVS, for predicting docking poses and binding affinities. Our approach outperforms other state-of-the-art methods on a wide range of benchmarks, partially due to our ability to model receptor flexibility. We incorporate this into a new open-source artificial intelligence accelerated virtual screening platform for drug discovery. Using this platform, we screen multi-billion compound libraries against two unrelated targets, a ubiquitin ligase target KLHDC2 and the human voltage-gated sodium channel NaV1.7. For both targets, we discover hit compounds, including seven hits (14% hit rate) to KLHDC2 and four hits (44% hit rate) to NaV1.7, all with single digit micromolar binding affinities. Screening in both cases is completed in less than seven days. Finally, a high resolution X-ray crystallographic structure validates the predicted docking pose for the KLHDC2 ligand complex, demonstrating the effectiveness of our method in lead discovery.

Tryptophan intake and pancreatic cancer: findings from a case-control study.

BACKGROUND: Pancreatic cancer is a leading cause of cancer-related death worldwide. Tryptophan plays a vital role in cell growth and maintenance as a building block of protein and coordination of organismal responses to environmental and dietary cues. Animal model study showed that dietary tryptophan improved treatment response in those who received chemotherapy or immune checkpoint inhibitors. Limited data are available assessing the association between tryptophan intake and risk of pancreatic cancer. We aimed to evaluate this association in a case-control study in Vietnam. METHODS: We analyzed data from a case-control study, including 3759 cancer cases and 2995 control subjects of whom 37 with pancreatic cancer cases. Tryptophan intake was derived from food frequency questionnaire. Unconditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for different levels of tryptophan intake with pancreatic cancer risk. RESULTS: Overall, tryptophan intake was inversely associated with pancreatic cancer risk in a dose-dependent manner. The ORs and 95% CIs of pancreatic cancer were 0.51 (0.29-0.92) for continuous scale, 0.27 (0.10-0.73) for tertile 2 and 0.34 (0.11-1.06) for tertile 3, compared with tertile 1 (the lowest intake) ( Ptrend = 0.02). In stratified analysis, this inverse association pattern was present among those with BMI < 23 kg/m 2 and ever drinkers. CONCLUSION: A diet with a higher intake of tryptophan was significantly associated with a lower incidence of pancreatic cancer among Vietnamese population. These suggest that dietary modification may be an effective strategy for primary prevention of pancreatic cancer development.

AmberTools.

AmberTools is a free and open-source collection of programs used to set up, run, and analyze molecular simulations. The newer features contained within AmberTools23 are briefly described in this Application note.

Channelopathy-causing mutations in the S45A/S45B and HA/HB helices of KCa2.3 and KCa3.1 channels alter their apparent Ca2+ sensitivity.

Small- and intermediate-conductance Ca2+-activated potassium (KCa2.x and KCa3.1, also called SK and IK) channels are activated exclusively by a Ca2+-calmodulin gating mechanism. Wild-type KCa2.3 channels have a Ca2+ EC50 value of ∼0.3 µM, while the apparent Ca2+ sensitivity of wild-type KCa3.1 channels is ∼0.27 µM. Heterozygous genetic mutations of KCa2.3 channels have been associated with Zimmermann-Laband syndrome and idiopathic noncirrhotic portal hypertension, while KCa3.1 channel mutations were reported in hereditary xerocytosis patients. KCa2.3_S436C and KCa2.3_V450L channels with mutations in the S45A/S45B helices exhibited hypersensitivity to Ca2+. The corresponding mutations in KCa3.1 channels also elevated the apparent Ca2+ sensitivity. KCa3.1_S314P, KCa3.1_A322V and KCa3.1_R352H channels with mutations in the HA/HB helices are hypersensitive to Ca2+, whereas KCa2.3 channels with the equivalent mutations are not. The different effects of the equivalent mutations in the HA/HB helices on the apparent Ca2+ sensitivity of KCa2.3 and KCa3.1 channels may imply distinct modulation of the two channel subtypes by the HA/HB helices. AP14145 reduced the apparent Ca2+ sensitivity of the hypersensitive mutant KCa2.3 channels, suggesting the potential therapeutic usefulness of negative gating modulators.

Structure-Activity Relationship Study of Subtype-Selective Positive Modulators of KCa2 Channels.

A series of modified N-cyclohexyl-2-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylpyrimidin-4-amine (CyPPA) analogues were synthesized by replacing the cyclohexane moiety with different 4-substituted cyclohexane rings, tyrosine analogues, or mono- and dihalophenyl rings and were subsequently studied for their potentiation of KCa2 channel activity. Among the N-benzene-N-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-4-pyrimidinamine derivatives, halogen decoration at positions 2 and 5 of benzene-substituted 4-pyrimidineamine in compound 2q conferred a ∼10-fold higher potency, while halogen substitution at positions 3 and 4 of benzene-substituted 4-pyrimidineamine in compound 2o conferred a ∼7-fold higher potency on potentiating KCa2.2a channels, compared to that of the parent template CyPPA. Both compounds retained the KCa2.2a/KCa2.3 subtype selectivity. Based on the initial evaluation, compounds 2o and 2q were selected for testing in an electrophysiological model of spinocerebellar ataxia type 2 (SCA2). Both compounds were able to normalize the abnormal firing of Purkinje cells in cerebellar slices from SCA2 mice, suggesting the potential therapeutic usefulness of these compounds for treating symptoms of ataxia.

Correction to: Oxford House Residents' Attitudes Toward Medication Assisted Treatment Use in Fellow Residents.

The original version of this article unfortunately contained a mistake in the author group, where co-authors Isabel Dovale, Noah Gelfman and Sarah Callahan were missed to include and Brandon Isler should be removed from the author group.

Oxford House Residents' Attitudes Toward Medication Assisted Treatment Use in Fellow Residents.

Methadone and buprenorphine/naloxone are medication assisted treatment (MAT) options for treating opioid use disorder, yet attitudes regarding their use within abstinence-based recovery homes have not been assessed. The present investigation examined attitudes regarding MAT utilization among residents living in Oxford Houses. This cross-sectional investigation compared residents (n = 87) receiving MAT whose recent drug use involved opioids, and two groups not receiving MATs; those who had used opioids and those who had used substances other than opioids. The vast majority of residents were not receiving MAT, yet 32% reported MAT histories. Negative attitudes regarding MAT were observed among residents who were not receiving MAT. Those presently receiving MAT reported mixed attitudes regarding the use of methadone and buprenorphine/naloxone, and two of these residents reported they had never been prescribed MAT. Findings suggest that abstinence-based recovery homes such as Oxford Houses may not be optimal resources for persons receiving MATs.