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Upregulation of Aurora kinases has been associated with increased tumor progression, and thus they are appealing targets for the development of anti-cancer therapies. In addition to have a critical role in cell cycle regulation, Aurora kinases have been shown to stabilize MYC-family oncoproteins for the maintenance of malignancy. Aurora kinase inhibitors such as Alisertib has demonstrated compelling anti-tumor efficacies; however, the reported side effects including serious haematological disturbances have limited its risk-benefit ratio in clinical use. In this study we discovered a novel pyrimidine-based Aurora kinase inhibitor compound A that degraded MYC- and MYCN- oncoproteins with better potency than Alisertib. The acyl-based prodrug design leads to the discovery of compound B which was able to regress MYC- or MYCN- overexpressing tumor xenografts including small cell lung cancer, neuroblastoma, hepatocellular carcinoma and medulloblastoma using a once-a-week (QW) oral dosing regimen. Pharmacokinetic studies revealed that the tumor/plasma ratio of compound B was about 20 at 24 h post drug administration, and the active compound remained detectable in the tumors after 7 days. No significant haematological or liver/kidney biochemical aberration was observed in mice treated with up to 500 mg/kg of DBPR728 on a QW dosing regimen in a 21-day cycle. The unique pharmacokinetic and molecular properties of compound B hold potential clinical promise for treating MYC- and MYCN- amplified tumors with manageable on-target haematological adverse effects caused by Aurora kinase inhibition. Citation Format: Ya-Hui Chi, Chun-Ping Chang, Teng-Kuang Yeh, Wan-Ping Wang, Yen-Ting Chen, Chia-Hua Tsai, Yan-Fu Chen, Yi-Yu Ke, Jing-Ya Wang, Ching-Ping Chen, Tsung-Chih Hsieh, Mine-Hsine Wu, Chiung-Tong Chen. Targeting myc-amplified cancers with a novel prodrug inhibiting aurora A kinase [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 523.

The A-type Aurora kinase is upregulated in many human cancers, and it stabilizes MYC-family oncoproteins, which have long been considered an undruggable target. Here, we describe the design and synthesis of a series of pyrimidine-based derivatives able to inhibit Aurora A kinase activity and reduce levels of cMYC and MYCN. Through structure-based drug design of a small molecule that induces the DFG-out conformation of Aurora A kinase, lead compound 13 was identified, which potently (IC50 < 200 nM) inhibited the proliferation of high-MYC expressing small-cell lung cancer (SCLC) cell lines. Pharmacokinetic optimization of 13 by prodrug strategies resulted in orally bioavailable 25, which demonstrated an 8-fold higher oral AUC (F = 62.3%). Pharmacodynamic studies of 25 showed it to effectively reduce cMYC protein levels, leading to >80% tumor regression of NCI-H446 SCLC xenograft tumors in mice. These results support the potential of 25 for the treatment of MYC-amplified cancers including SCLC.

Currently, there is a significant unmet need for novel analgesics with fewer side effects. In this study, we carried out structural modification of a hit compound previously identified in an artificial-intelligence (AI) virtual screening and discovered the potent analgesic, benzo[b]thiophene-2-carboxamide analog (compound 25) with new structural scaffold. We investigated the signaling pathways of opioid receptors mediated by compound 25, and found this racemic compound activated mu-opioid receptor through the cyclic adenosine monophosphate (cAMP) and β-arrestin-2-mediated pathways with strong potency and efficacy, and accompanying nociceptin-orphanin FQ opioid peptide and delta-opioid receptors through the cAMP pathway with weak potencies. Compound 25 elicited potent antinociception in thermal-stimulated pain (ED

Machine learning is a well-known approach for virtual screening. Recently, deep learning, a machine learning algorithm in artificial neural networks, has been applied to the advancement of precision medicine and drug discovery. In this study, we performed comparative studies between deep neural networks (DNN) and other ligand-based virtual screening (LBVS) methods to demonstrate that DNN and random forest (RF) were superior in hit prediction efficiency. By using DNN, several triple-negative breast cancer (TNBC) inhibitors were identified as potent hits from a screening of an in-house database of 165,000 compounds. In broadening the application of this method, we harnessed the predictive properties of trained model in the discovery of G protein-coupled receptor (GPCR) agonist, by which computational structure-based design of molecules could be greatly hindered by lack of structural information. Notably, a potent (~ 500 nM) mu-opioid receptor (MOR) agonist was identified as a hit from a small-size training set of 63 compounds. Our results show that DNN could be an efficient module in hit prediction and provide experimental evidence that machine learning could identify potent hits in silico from a limited training set.

Nitro-fatty acids are a class of endogenous electrophilic lipid mediators with anti-inflammatory and cytoprotective effects in a wide range of inflammatory and fibrotic disease models. While these beneficial biological effects of nitro-fatty acids are mainly attributed to their ability to form covalent adducts with proteins, only a small number of proteins are known to be nitro-alkylated and the scope of protein nitro-alkylation remains undetermined. Here we describe the synthesis and application of a clickable nitro-fatty acid probe for the detection and first global identification of mammalian proteins that are susceptible to nitro-alkylation. 184 high confidence nitro-alkylated proteins were identified in THP1 macrophages, majority of which are novel targets of nitro-fatty acids, including extended synaptotagmin 2 (ESYT2), signal transducer and activator of transcription 3 (STAT3), toll-like receptor 2 (TLR2), retinoid X receptor alpha (RXRα) and glucocorticoid receptor (NR3C1). In particular, we showed that 9-nitro-oleate covalently modified and inhibited dexamethasone binding to NR3C1. Bioinformatic analyses revealed that nitro-alkylated proteins are highly enriched in endoplasmic reticulum and transmembrane proteins, and are overrepresented in lipid metabolism and transport pathways. This study significantly expands the scope of protein substrates targeted by nitro-fatty acids in living cells and provides a useful resource towards understanding the pleiotropic biological roles of nitro-fatty acids as signaling molecules or as multi-target therapeutic agents.

Somatic mutation in the KCNJ5 gene is a common driver of autonomous aldosterone overproduction in aldosterone-producing adenomas (APA). KCNJ5 mutations contribute to a loss of potassium selectivity, and an inward Na+ current could be detected in cells transfected with mutated KCNJ5. Among 223 unilateral primary aldosteronism (uPA) individuals with a KCNJ5 mutation, we identified 6 adenomas with a KCNJ5 p.Gly387Arg (G387R) mutation, previously unreported in uPA patients. The six uPA patients harboring mutant KCNJ5-G387R were older, had a longer hypertensive history, and had milder elevated preoperative plasma aldosterone levels than those APA patients with more frequently detected KCNJ5 mutations. CYP11B2 immunohistochemical staining was only positive in three adenomas, while the other three had co-existing multiple aldosterone-producing micronodules. The bioinformatics analysis predicted that function of the KCNJ5-G387R mutant channel could be pathological. However, the electrophysiological experiment demonstrated that transfected G387R mutant cells did not have an aberrantly stimulated ion current, with lower CYP11B2 synthesis and aldosterone production, when compared to that of the more frequently detected mutant KCNJ5-L168R transfected cells. In conclusion, mutant KCNJ5-G387R is not a functional KCNJ5 mutation in unilateral PA. Compared with other KCNJ5 mutations, the observed mildly elevated aldosterone expression actually hindered the clinical identification of clinical unilateral PA. The KCNJ5-G387R mutation needs to be distinguished from functional KCNJ5 mutations during genomic analysis in APA evaluation because of its functional silence.

We identified, via high-throughput screening using a FLIPR® calcium assay, compound 1, which incorporated a dihydroquinolinyl-2-oxoethylsulfanyl-(1H,5H)-pyrimidinedione core and activated the μ-opioid receptor (MOR) in the presence of naloxone or naltrexone. A structure-activity relationship study of the analogs of 1 led to the design of compound 21, which activated MOR in the presence of naloxone with an EC

Nitro-fatty acids are a class of endogenous electrophilic lipid mediators with anti-inflammatory and cytoprotective effects in a wide range of inflammatory and fibrotic disease models. While these beneficial biological effects of nitro-fatty acids are mainly attributed to their ability to form covalent adducts with proteins, only a small number of proteins are known to be nitro-alkylated and the scope of protein nitro-alkylation remains undetermined. Here we describe the synthesis and application of a clickable nitro-fatty acid probe for the detection and first global identification of mammalian proteins that are susceptible to nitro-alkylation. 184 high confidence nitro-alkylated proteins were identified in human macrophages, majority of which are novel targets of nitro-fatty acids, including Extended synaptotagmin 2 (ESYT2), Signal transducer and activator of transcription 3 (STAT3), Toll-like receptor 2 (TLR2), Retinoid X receptor alpha (RXRα) and Glucocorticoid receptor (NR3C1). In particular, we showed that 9-nitro-oleate covalently modified and inhibited dexamethasone binding to NR3C1. Bioinformatic analyses revealed that nitro-alkylated proteins are highly enriched in endoplasmic reticulum and transmembrane proteins, and are overrepresented in lipid metabolism and transport pathways. This study significantly expands the scope of protein substrates targeted by nitro-fatty acids in living cells and provides a useful resource towards understanding the pleiotropic biological roles of nitro-fatty acids as signaling molecules or as multi-target therapeutic agents.

Insulin resistance and obesity are pivotal features of type 2 diabetes mellitus. Peroxisome proliferator-activated receptor γ (PPARγ) is a master transcriptional regulator of systemic insulin sensitivity and energy balance. The anti-diabetic drug thiazolidinediones are potent synthetic PPARγ ligands and insulin sensitizers with undesirable side effects including increased adiposity, fluid retention, and osteoporosis, which limit their clinical use. We and others have proved that 15-keto-PGE2 is an endogenous natural PPARγ ligand. 15-keto-PGE2 is catalyzed by prostaglandin reductase 2 (PTGR2) to become inactive metabolites. We found that 15-keto-PGE2 level is increased in Ptgr2 knockout mice. Ptgr2 knockout mice were protected from diet-induced obesity, insulin resistance, and hepatic steatosis without fluid retention nor reduced bone mineral density. Diet-induced obese mice have drastically reduced 15-keto-PGE2 levels compared to lean mice. Administration of 15-keto-PGE2 markedly improved insulin sensitivity and prevented diet-induced obesity in mice. We demonstrated that 15-keto-PGE2 activates PPARγ through covalent binding to its cysteine 285 residue at helix 3, which restrained its binding pocket between helix 3 and β-sheets of the PPARγ ligand binding domain. This binding mode differs from the helix12-dependent binding mode of thiazolidinediones. We further identified a small-molecule PTGR2 inhibitor BPRPT245, which interferes the interaction between the substrate-binding sites of PTGR2 and 15-keto-PGE2. BPRPT245 increased 15-keto-PGE2 concentration, activated PPARγ, and promoted glucose uptake in adipocytes. BPRPT245 also prevented diet-induced obesity, improved insulin sensitivity and glucose tolerance, lowers fasting glucose without fluid retention and osteoporosis. In humans, reduced serum 15-keto-PGE2 levels were observed in patients with type 2 diabetes compared with controls. Furthermore, serum 15-keto-PGE2 levels correlate inversely with insulin resistance and fasting glucose in non-diabetic humans. In conclusion, we identified a new therapeutic approach to improve insulin sensitivity and protect diet-induced obesity through increasing endogenous natural PPARγ ligands without side effects of thiazolidinediones.

Melanoma is the most serious form of skin cancer but its medication is still far from being safe and thoroughly effective. The search of novel therapeutic approaches represents therefore a health emergency to push through eagerly. In this study, we describe a novel class of dual c-Kit/Aur inhibitors, characterized by a 1,2,4-triazole core and developed by a structure-based optimization of a previously developed hit, and report the evidence of their significance as drug candidates for the treatment of melanoma. Compound 6a, merging the best inhibitory profile against the target kinases, showed anti-proliferative efficacy against the human melanoma cell lines A2058, expressing the BRAF V600D mutation, and WM266-4, expressing BRAF V600E. Significantly, it displayed also a highly synergistic profile when tested in combination with vemurafenib, thus proving its efficacy not only per se but even in a combination therapy, which is nowadays acknowledged as the cornerstone approach of the forthcoming tumour management.

Morphine is widely used for the treatment of severe pain. This analgesic effect is mediated principally by the activation of μ-opioid receptors (MOR). However, prolonged activation of MOR also results in tolerance, dependence, addiction, constipation, nausea, sedation, and respiratory depression. To address this problem, we sought alternative ways to activate MOR – either by use of novel ligands, or via a novel activation mechanism. To this end, a series of compounds were screened using a sensitive CHO-K1/MOR/Gα15 cell-based FLIPR® calcium high-throughput screening (HTS) assay, and the bithiazole compound 5a was identified as being able activate MOR in combination with naloxone. Structural modifications of 5a resulted in the discovery of lead compound 5j, which could effectively activate MOR in combination with the MOR antagonist naloxone or naltrexone. In vivo, naloxone in combination with 100 mg/kg of compound 5j elicited antinociception in a mouse tail-flick model with an ED50 of 17.5 ± 4 mg/kg. These results strongly suggest that the mechanism by which the 5j/naloxone combination activates MOR is worthy of further study, as its discovery has the potential to yield an entirely novel class of analgesics.

Significance A highly selective, safe, and potent CXCR4 antagonist, BPRCX807, has been designed and experimentally validated in various hepatocellular carcinoma models. Through combination therapy, it can synergize with either a kinase (e.g., sorafenib) or checkpoint inhibitor (e.g. anti–PD-1) to augment effectiveness of current anticancer treatments. With its unique mode of action, a new anticancer strategy for preventing cell migration and metastasis is provided., The CXC chemokine receptor type 4 (CXCR4) receptor and its ligand, CXCL12, are overexpressed in various cancers and mediate tumor progression and hypoxia-mediated resistance to cancer therapy. While CXCR4 antagonists have potential anticancer effects when combined with conventional anticancer drugs, their poor potency against CXCL12/CXCR4 downstream signaling pathways and systemic toxicity had precluded clinical application. Herein, BPRCX807, known as a safe, selective, and potent CXCR4 antagonist, has been designed and experimentally realized. In in vitro and in vivo hepatocellular carcinoma mouse models it can significantly suppress primary tumor growth, prevent distant metastasis/cell migration, reduce angiogenesis, and normalize the immunosuppressive tumor microenvironment by reducing tumor-associated macrophages (TAMs) infiltration, reprogramming TAMs toward an immunostimulatory phenotype and promoting cytotoxic T cell infiltration into tumor. Although BPRCX807 treatment alone prolongs overall survival as effectively as both marketed sorafenib and anti–PD-1, it could synergize with either of them in combination therapy to further extend life expectancy and suppress distant metastasis more significantly.

This study investigates the effects of the vent-area on bubble-microstructure and shrinkage variation of gas-assisted foam-injection molding (GAFIM). The molding material is polystyrene (PS), and the gas foaming agent is nitrogen (N 2 ). This study carried out the injection experiment with and without GAFIM to observe the molding characteristics of gas-filling pressure variation. In addition, the integration of vent-area volumes and cavity pressure measurement was developed to achieve foam growth and microstructure inside the sample to observe the effect of with and without vent-area on shrinkage variation and correlated pressure distribution near gate position during the filling process. The experimental results revealed that with the vent-area, the sample dimension shrinkage was relatively improved and the sample weight was reduced. On the other hand, the bubble-distribution increased with the changes in the volume of the vent-area and gas-filling pressure as the foam growth space increased.

Background New therapeutic options to address the ongoing COVID-19 pandemic are urgently needed. One possible strategy is the repurposing of existing drugs approved for other indications as antiviral agents for SARS-CoV-2. Due to the commercial unavailability of SARS-CoV-2 drugs for treating COVID-19, we screened approximately 250 existing drugs or pharmacologically active compounds for their inhibitory activities against feline infectious peritonitis coronavirus (FIPV) and human coronavirus OC43 (HCoV-OC43), a human coronavirus in the same genus (Betacoronavirus) as SARS-CoV-2. Methods FIPV was proliferated in feline Fcwf-4 cells and HCoV-OC43 in human HCT-8 cells. Viral proliferation was assayed by visualization of cytopathic effects on the infected Fcwf-4 cells and immunofluorescent assay for detection of the nucleocapsid proteins of HCoV-OC43 in the HCT-8 cells. The concentrations (EC50) of each drug necessary to diminish viral activity to 50% of that for the untreated controls were determined. The viabilities of Fcwf-4 and HCT-8 cells were measured by crystal violet staining and MTS/PMS assay, respectively. Results Fifteen out of the 252 drugs or pharmacologically active compounds screened were found to be active against both FIPV and HCoV-OC43, with EC50 values ranging from 11 nM to 75 μM. They are all old drugs as follows, anisomycin, antimycin A, atovaquone, chloroquine, conivaptan, emetine, gemcitabine, homoharringtonine, niclosamide, nitazoxanide, oligomycin, salinomycin, tilorone, valinomycin, vismodegib. Conclusion All of the old drugs identified as having activity against FIPV and HCoV-OC43 have seen clinical use in their respective indications and are associated with known dosing schedules and adverse effect or toxicity profiles in humans. Those, when later confirmed to have an anti-viral effect on SARS-CoV-2, should be considered for immediate uses in COVID-19 patients., Graphical abstract Image 1

The coronavirus (CoV) disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is a health threat worldwide. Viral main protease (Mpro, also called 3C‐like protease [3CLpro]) is a therapeutic target for drug discovery. Herein, we report that GC376, a broad-spectrum inhibitor targeting Mpro in the picornavirus-like supercluster, is a potent inhibitor for the Mpro encoded by SARS-CoV-2, with a half-maximum inhibitory concentration (IC50) of 26., The coronavirus (CoV) disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is a health threat worldwide. Viral main protease (Mpro, also called 3C‐like protease [3CLpro]) is a therapeutic target for drug discovery. Herein, we report that GC376, a broad-spectrum inhibitor targeting Mpro in the picornavirus-like supercluster, is a potent inhibitor for the Mpro encoded by SARS-CoV-2, with a half-maximum inhibitory concentration (IC50) of 26.4 ± 1.1 nM. In this study, we also show that GC376 inhibits SARS-CoV-2 replication with a half-maximum effective concentration (EC50) of 0.91 ± 0.03 μM. Only a small portion of SARS-CoV-2 Mpro was covalently modified in the excess of GC376 as evaluated by mass spectrometry analysis, indicating that improved inhibitors are needed. Subsequently, molecular docking analysis revealed that the recognition and binding groups of GC376 within the active site of SARS-CoV-2 Mpro provide important new information for the optimization of GC376. Given that sufficient safety and efficacy data are available for GC376 as an investigational veterinary drug, expedited development of GC376, or its optimized analogues, for treatment of SARS-CoV-2 infection in human is recommended.

Background The ongoing COVID-19 pandemic has caused more than 193,825 deaths during the past few months. A quick-to-be-identified cure for the disease will be a therapeutic medicine that has prior use experiences in patients in order to resolve the current pandemic situation before it could become worsening. Artificial intelligence (AI) technology is hereby applied to identify the marketed drugs with potential for treating COVID-19. Methods An AI platform was established to identify potential old drugs with anti-coronavirus activities by using two different learning databases; one consisted of the compounds reported or proven active against SARS-CoV, SARS-CoV-2, human immunodeficiency virus, influenza virus, and the other one containing the known 3C-like protease inhibitors. All AI predicted drugs were then tested for activities against a feline coronavirus in in vitro cell-based assay. These assay results were feedbacks to the AI system for relearning and thus to generate a modified AI model to search for old drugs again. Results After a few runs of AI learning and prediction processes, the AI system identified 80 marketed drugs with potential. Among them, 8 drugs (bedaquiline, brequinar, celecoxib, clofazimine, conivaptan, gemcitabine, tolcapone, and vismodegib) showed in vitro activities against the proliferation of a feline infectious peritonitis (FIP) virus in Fcwf-4 cells. In addition, 5 other drugs (boceprevir, chloroquine, homoharringtonine, tilorone, and salinomycin) were also found active during the exercises of AI approaches. Conclusion Having taken advantages of AI, we identified old drugs with activities against FIP coronavirus. Further studies are underway to demonstrate their activities against SARS-CoV-2 in vitro and in vivo at clinically achievable concentrations and doses. With prior use experiences in patients, these old drugs if proven active against SARS-CoV-2 can readily be applied for fighting COVID-19 pandemic.

Twenty five novel chemical analogs of the previously reported Aurora kinase inhibitor BPR1K653 (1-(4-(2-((5-chloro-6-phenylfuro[2,3-d]pyrimidin-4-yl)amino)ethyl)phenyl)-3-(2-((dimethylamino)methyl)phenyl)urea) have been designed, synthesized, and evaluated by Aurora-A and Aurora-B enzymatic kinase activity assays. Similar to BPR1K653, analogs 3b-3h bear alkyl or tertiary amino group at the ortho position of the phenylurea, and showed equal or better inhibition activity for Aurora-B over Aurora-A. Conversely, preferential Aurora-A inhibition activity was observed when the same functional group was moved to the meta position of the phenylurea. Compounds 3m and 3n, both of which harbor a tertiary amino group at the meta position of the phenylurea, showed 10–16 fold inhibition selectivity for Aurora-A over Aurora-B. The in vitro kinase inhibition results were verified by Western blot analysis, and indicated that compounds 3m and 3n were more than 75-fold superior in inhibiting T-loop autophosphorylation of Aurora-A (Thr288), compared to Aurora-B (Thr232) in HCT116 colon carcinoma cells. The computational docking analysis suggested that the tertiary amine at the meta position of the phenylurea formed a more stable interaction with residues in the back pocket of Aurora-A than in Aurora-B, a possible explanation for the observed discrepancy in the selectivity. These results support an alternative small molecule design strategy targeting the back pocket of Aurora kinases for selective isoform inhibition.

CXCR4 antagonists (e.g., PlerixaforTM ) have been successfully validated as stem cell mobilizers for peripheral blood stem cell transplantation. Applications of the CXCR4 antagonists have heralded the era of cell-based therapy and opened a potential therapeutic horizon for many unmet medical needs such as kidney injury, ischemic stroke, cancer, and myocardial infarction. In this review, we first introduce the central role of CXCR4 in diverse cellular signaling pathways and discuss its involvement in several disease progressions. We then highlight the molecular design and optimization strategies for targeting CXCR4 from a large number of case studies, concluding that polyamines are the preferred CXCR4-binding ligands compared to other structural options, presumably by mimicking the highly positively charged natural ligand CXCL12. These results could be further justified with computer-aided docking into the CXCR4 crystal structure wherein both major and minor subpockets of the binding cavity are considered functionally important. Finally, from the clinical point of view, CXCR4 antagonists could mobilize hematopoietic stem/progenitor cells with long-term repopulating capacity to the peripheral blood, promising to replace surgically obtained bone marrow cells as a preferred source for stem cell transplantation.

Humans have two glutaminase genes, GLS (GLS1) and GLS2, each of which has two alternative transcripts: the kidney isoform (KGA) and glutaminase C (GAC) for GLS, and the liver isoform (LGA) and glutaminase B (GAB) for GLS2. Initial hit compound (Z)-5-((1-(4-bromophenyl)-2,5-dimethyl-1H-pyrrol-3-yl)methylene)thiazolidine-2,4-dione (2), a thiazolidine-2,4-dione, was obtained from a high throughput screening of 40 000 compounds against KGA. Subsequently, a series of thiazolidine-2,4-dione derivatives was synthesized. Most of these were found to inhibit KGA and GAC with comparable activities, were less potent inhibitors of GAB, and were moderately selective for GLS1 over GLS2. The relationships between chemical structure, activity, and selectivity were investigated. The lead compounds obtained were found to (1) offer in vitro cellular activities for inhibiting cell growth, clonogenicity, and cellular glutamate production, (2) exhibit high concentrations of exposure in plasma by a pharmacokinetic study, and (3) reduce the tumor size of xenografted human pancreatic AsPC-1 carcinoma cells in mice.

Naloxone is an alkaloid antagonist that acts as an antidote to opioids through the mu-opioid receptor (MOR), a G protein-coupled receptor. However, its binding site on the MOR remains unknown. To investigate the binding interfaces necessary for naloxone and MOR, available structural information was combined with a cell-based photocrosslinking approach. Computer prediction revealed that four binding sites on MOR were required for naloxone binding. In addition, in the photocrosslinking approach, an amber stop codon was used to replace the sense codon of the MOR at 266 selected individual positions, in order to introduce the photoreactive amino acid p-benzoyl-l-phenylalanine (BzF) into MOR to evaluate the results of the computer analysis. The BzF-incorporated MOR mutant genes were expressed in CHO cells, in which MOR retained the ability to interact with its ligands, such as morphine, and exhibited MOR-dependent activation of ERK signaling following morphine stimulation. Notably, after treatment with tritium-labeled naloxone and exposure to UV light, we observed naloxone crosslinking with BzF replacement at hydrophobic residues and some polar/uncharged residues in the computer-predicted sites 1 and 3, indicating that these two sites in the MOR interact with naloxone. In conclusion, these results indicate that MOR has two naloxone binding sites and that the hydrophobic and polar/uncharged residues within these sites are important for naloxone binding.

// Yung Chang Hsu 1, * , Mohane Selvaraj Coumar 2, * , Wen-Chieh Wang 1, * , Hui-Yi Shiao 1, * , Yi-Yu Ke 1 , Wen-Hsing Lin 1 , Ching-Chuan Kuo 1 , Chun-Wei Chang 1 , Fu-Ming Kuo 1 , Pei-Yi Chen 1 , Sing-Yi Wang 1 , An-Siou Li 1 , Chun-Hwa Chen 1 , Po-Chu Kuo 1 , Ching-Ping Chen 1 , Ming-Hsine Wu 1 , Chen-Lung Huang 1 , Kuei-Jung Yen 1 , Yun-I Chang 1 , John T.-A. Hsu 1 , Chiung-Tong Chen 1 , Teng-Kuang Yeh 1 , Jen-Shin Song 1 , Chuan Shih 1 , Hsing-Pang Hsieh 1,3 1 Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, Taiwan, ROC 2 Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Kalapet, Puducherry, India 3 Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan, ROC * These authors contributed equally to this work Correspondence to: Hsing-Pang Hsieh, email: hphsieh@nhri.org.tw Keywords: acute myeloid leukemia, aurora kinase, FLT3, quinazoline, multi-kinase inhibitor Received: July 25, 2016 Accepted: November 07, 2016 Published: November 15, 2016 ABSTRACT The design and synthesis of a quinazoline-based, multi-kinase inhibitor for the treatment of acute myeloid leukemia (AML) and other malignancies is reported. Based on the previously reported furanopyrimidine 3, quinazoline core containing lead 4 was synthesized and found to impart dual FLT3/AURKA inhibition (IC 50 = 127/5 nM), as well as improved physicochemical properties. A detailed structure-activity relationship study of the lead 4 allowed FLT3 and AURKA inhibition to be finely tuned, resulting in AURKA selective (5 and 7; 100-fold selective over FLT3), FLT3 selective (13; 30-fold selective over AURKA) and dual FLT3/AURKA selective (BPR1K871; IC 50 = 19/22 nM) agents. BPR1K871 showed potent anti-proliferative activities in MOLM-13 and MV4-11 AML cells (EC 50 ~ 5 nM). Moreover, kinase profiling and cell-line profiling revealed BPR1K871 to be a potential multi-kinase inhibitor. Functional studies using western blot and DNA content analysis in MV4-11 and HCT-116 cell lines revealed FLT3 and AURKA/B target modulation inside the cells. In vivo efficacy in AML xenograft models (MOLM-13 and MV4-11), as well as in solid tumor models (COLO205 and Mia-PaCa2), led to the selection of BPR1K871 as a preclinical development candidate for anti-cancer therapy. Further detailed studies could help to investigate the full potential of BPR1K871 as a multi-kinase inhibitor.

Aurora kinases have emerged as important anticancer targets so that there are several inhibitors have advanced into clinical study. Herein, we identified novel indazole derivatives as potent Aurora kinases inhibitors by utilizing in silico fragment-based approach and knowledge-based drug design. After intensive hit-to-lead optimization, compounds 17 (dual Aurora A and B), 21 (Aurora B selective) and 30 (Aurora A selective) possessed indazole privileged scaffold with different substituents, which provide sub-type kinase selectivity. Computational modeling helps in understanding that the isoform selectivity could be targeted specific residue in the Aurora kinase binding pocket in particular targeting residues Arg220, Thr217 or Glu177.

Epidermal growth factor receptor (EGFR)-targeted therapy in non-small cell lung cancer represents a breakthrough in the field of precision medicine. Previously, we have identified a lead compound, furanopyrimidine 2, which contains a (S)-2-phenylglycinol structure as a key fragment to inhibit EGFR. However, compound 2 showed high clearance and poor oral bioavailability in its pharmacokinetics studies. In this work, we optimized compound 2 by scaffold hopping and exploiting the potent inhibitory activity of various warhead groups to obtain a clinical candidate, 78 (DBPR112), which not only displayed a potent inhibitory activity against EGFRL858R/T790M double mutations but also exhibited tenfold potency better than the third-generation inhibitor, osimertinib, against EGFR and HER2 exon 20 insertion mutations. Overall, pharmacokinetic improvement through lead-to-candidate optimization yielded fourfold oral AUC better that afatinib along with F = 41.5%, an encouraging safety profile, and significant antitumor efficacy in in vivo xenograft models. DBPR112 is currently undergoing phase 1 clinical trial in Taiwan.

Small cell lung cancer (SCLC) accounts for approximately 15% of all lung cancers, leading to ~30,000 deaths each year in the United States. SCLC patients often present with metastasis at time of diagnosis, excluding surgery as a treatment option. While patients show high response rate to standard chemotherapy such as cisplatin/etoposide, they soon develop drug resistance and disease progression. Therefore, new therapeutic strategies are urgently needed for SCLC. BPR6K609S0 is a novel Aurora kinase inhibitor which has been designed to inhibit the kinase activity of Aurora A, and induces proteasome-mediated degradation of MYC. The BPR6K609S0 active molecule provokes cell apoptosis and inhibits proliferation of several SCLC cell lines with IC50 < 100 nM. Oral administration of BPR6K609 induces >60 % tumor regression in a NCI-H446 xenograft mouse model. In addition, BPR6K609 further reduces tumor progression in NCI-H446 xenograft mice pre-treated with LY3295668, an Aurora A-selective inhibitor which is currently under clinical investigation. These results support the clinical potential of BRP6K609S0 for the treatment of SCLC. Citation Format: Ya-Hui Chi, Chun-Ping Chang, Yi-Yu Ke, Wen-Hsing Lin, Wan-Ping Wang, Chia-Hua Tsai, Yen-Ting Chen, Yu-Jie Su, Ming-Chun Hung, Zhong-Wei Wu, Mine-Hsine Wu, Teng-Kuang Yeh, Ching-Ping Chen, Jen-Shin Song, Chiung-Tong Chen, Chuan Shih. BPR6K609: An Aurora kinase inhibitor targeting small cell lung cancer with MYC amplification [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1937.

Background Lung cancer has the highest rate of morbidity and mortality among various cancer types, being responsible for over 1.69 million deaths per year. Approximately 80–85% of the lung cancer patients diagnosed present non-small cell lung cancer (NSCLC), while 10–15% present small cell lung cancer (SCLC). Mutations in the epidermal growth factor receptor (EGFR) have been observed in ∼50% of patients, in particular, in East Asian NSCLC patients. The single-point mutation L858R (exon 21) and amino acids deletions in the tyrosine kinase (TK) domain (exon 19) constitute 90% of all EGFR-activating mutations. Methods We introduced an acrylamide group as a Michael acceptor, resulting in compound 2, which showed potent in vitroactivity in both wild and mutant EGFR kinases and potent anti-proliferative activity in HCC827 lung cancer cell line. In this work, we apply SBDD to guide the optimization of lead compound 2and perform a detailed structure-activity relationship (SAR) study to bring this drug candidate into the next development stage. Results We optimized the compound 2by scaffold hopping and by exploiting the potent inhibitory activity of various warhead groups. The results of the multi-objective optimization obtained the clinical candidate, compound 78 (DBPR112), which not only displayed a potent inhibitory activity against EGFR L858R/T790M double mutations, but also exhibited 10-fold potency better than 3rd generation inhibitor, osimertinib, against three EGFR and one HER2 exon 20 insertion mutations, since there are currently no EGFR-directed therapies approved specifically for the treatment of this mutation. Conclusions X-ray co-crystal study of EGFRWTKinase and compound 78 revealed the potential of future design for mutant-selective inhibitors. Finally, furanopyrimidine 78 was selected as a clinical candidate to conduct all preclinical experiments and is currently undergoing phase 1 clinical trial in Taiwan. Clinical trial identification NCT03246854. Legal entity responsible for the study The authors. Funding National Health Research Institutes, Taiwan. Disclosure All authors have declared no conflicts of interest.

The function of the CXCR4/CXCL12 axis accounts for many disease indications, including tissue/nerve regeneration, cancer metastasis, and inflammation. Blocking CXCR4 signaling with its antagonists may lead to moving out CXCR4+ cell types from bone marrow to peripheral circulation. We have discovered a novel series of pyrimidine-based CXCR4 antagonists, a representative (i.e., 16) of which was tolerated at a higher dose and showed better HSC-mobilizing ability at the maximal response dose relative to the approved drug 1 (AMD3100), and thus considered a potential drug candidate for PBSCT indication. Docking compound 16 into the X-ray crystal structure of CXCR4 receptor revealed that it adopted a spider-like conformation striding over both major and minor subpockets. This putative binding mode provides a new insight into CXCR4 receptor–ligand interactions for further structural modifications.

It is now known that "gain of function" mutations of RET (REarranged during Transfection) kinase are specific and key oncogenic events in the onset of thyroid gland cancers such as the Medullary Thyroid Carcinoma (MTC). Although a number of RET inhibitors exist and are capable of inhibiting RET variants, in which mutations are outside the enzyme active site, the majority becomes dramatically ineffective when mutations are within the protein active site (V804L and V804M). Pursuing a receptor-based virtual screening against the kinase domain of RET, we found that compound 5 is able to inhibit efficiently both wild type and V804L mutant RET. Compound 5 was able to significantly reduce proliferation of both commercially available TT cell lines and surgical thyroid tissues obtained from patients with MTC and displayed a suitable drug-like profile, thus standing out as a promising candidate for further development towards the treatment of clinically unresponsive MTC.

Motivated by the pivotal role of CXCR4 as an HIV entry co-receptor, we herein report a de novo hit-to-lead effort on the identification of subnanomolar purine-based CXCR4 antagonists against HIV-1 infection. Compound 24, with an EC50 of 0.5 nM against HIV-1 entry into host cells and an IC50 of 16.4 nM for inhibition of radioligand stromal-derived factor-1α (SDF-1α) binding to CXCR4, was also found to be highly selective against closely related chemokine receptors. We rationalized that compound 24 complementarily interacted with the critical CXCR4 residues that are essential for binding to HIV-1 gp120 V3 loop and subsequent viral entry. Compound 24 showed a 130-fold increase in anti-HIV activity compared to that of the marketed CXCR4 antagonist, AMD3100 (Plerixafor), whereas both compounds exhibited similar potency in mobilization of CXCR4(+)/CD34(+) stem cells at a high dose. Our study offers insight into the design of anti-HIV therapeutics devoid of major interference with SDF-1α function.

Morphine antinociceptive tolerance is highly correlated with its poor ability to promote mu-opioid– receptor (MOR) endocytosis. Our objective was to discover a novel positive allosteric modulator of MOR to enhance morphine-induced MOR endocytosis. We used high-throughput screening to identify several cardiotonic steroids as positive allosteric modulators of morphine-induced MOR endocytosis having high potency and efficacy, independently of Na+/K+-ATPase inhibition. Convallatoxin was found to enhance morphine-induced MOR endocytosis through an adaptor protein 2/clathrin-dependent mechanism without regulating G protein- or β-arrestin-mediated pathways. Both F243 and I292 residues of MOR were essential to the effect of convallatoxin on MOR endocytosis. Co-treatment with chronic morphine and convallatoxin reduced morphine tolerance in animal models of acute thermal pain and chronic inflammatory pain. Acute convallatoxin administration reversed morphine tolerance in morphine-tolerant mice. These findings suggest that cardiotonic steroids are potentially therapeutic for morphine side effects and open a new avenue for the study of MOR trafficking.

Here we report for the first time the use of fit quality (FQ), a ligand efficiency (LE) based measure for virtual screening (VS) of compound libraries. The LE based VS protocol was used to screen an in-house database of 125,000 compounds to identify aurora kinase A inhibitors. First, 20 known aurora kinase inhibitors were docked to aurora kinase A crystal structure (PDB ID: 2W1C); and the conformations of docked ligand were used to create a pharmacophore (PH) model. The PH model was used to screen the database compounds, and rank (PH rank) them based on the predicted IC50 values. Next, LE_Scale, a weight-dependant LE function, was derived from 294 known aurora kinase inhibitors. Using the fit quality (FQ = LE/LE_Scale) score derived from the LE_Scale function, the database compounds were reranked (PH_FQ rank) and the top 151 (0.12% of database) compounds were assessed for aurora kinase A inhibition biochemically. This VS protocol led to the identification of 7 novel hits, with compound 5 showing aurora kinase A IC50 = 1.29 μM. Furthermore, testing of 5 against a panel of 31 kinase reveals that it is selective toward aurora kinase A & B, with

Computer-guided drug design is a powerful tool for drug discovery. Herein we disclose the use of this approach for the discovery of dual FMS-like receptor tyrosine kinase-3 (FLT3)-Aurora A inhibitors against cancer. An Aurora hit compound was selected as a starting point, from which 288 virtual molecules were screened. Subsequently, some of these were synthesized and evaluated for their capacity to inhibit FLT3 and Aurora kinase A. To further enhance FLT3 inhibition, structure-activity relationship studies of the lead compound were conducted through a simplification strategy and bioisosteric replacement, followed by the use of computer-guided drug design to prioritize molecules bearing a variety of different terminal groups in terms of favorable binding energy. Selected compounds were then synthesized, and their bioactivity was evaluated. Of these, one novel inhibitor was found to exhibit excellent inhibition of FLT3 and Aurora kinase A and exert a dramatic antiproliferative effect on MOLM-13 and MV4-11 cells, with an IC50 value of 7 nM. Accordingly, it is considered a highly promising candidate for further development.

Series of N-substituted carbazole analogues bearing an indole ring were synthesized as anti-methicillin-resistant Staphylococcus aureus (MRSA) agents from a molecular hybridization approach. The representative compound 19 showed an MIC = 1 μg/mL against a panel of MRSA clinical isolates as it possessed comparable in vitro activities to that of vancomycin. Moreover, compound 19 also exhibited MIC = 1 μg/mL activities against a recent identified Z172 MRSA strain (vancomycin-intermediate and daptomycin-nonsusceptible phenotype) and the vancomycin-resistant Enterococcus faecalis (VRE) strain. In a mouse model with lethal infection of MRSA (4N216), a 75% survival rate was observed after a single dose of compound 19 was intravenously administered at 20 mg/kg. In light of their equipotent activities against different MRSA isolates and VRE strain, the data underscore the importance of designed hybrid series for the development of new N-substituted carbazoles as potential anti-MRSA agents.

Small cell lung cancer (SCLC) is one the most aggressive tumors with poor survival rate. SCLC patients often present with metastasis at time of diagnosis, excluding surgery as a treatment option. While patients show high response rate to standard chemotherapy such as cisplatin/etoposide, they soon develop drug resistance and disease progression. Therefore, new therapeutic strategies are urgently needed for SCLC. Several characteristics of SCLC such as aggressiveness and drug resistance could attribute to the existence of a cancer stem cell (CSC) subpopulation in SCLC. The SCLC cell line NCI-H446 has been shown to present high degree of stemness and express stem cell markers including CD133, OCT4, MYC and Nestin. Here we develop a pyrimidine-based small molecule BPR6K471 which potently inhibits Aurora kinase activities in enzymatic- and cell- based assays. BPR6K471 efficiently (IC50 = 66 nM) inhibits proliferation of NCI-H446, and reduces the expression of stem-cell markers. In addition, intravenous injection of BPR6K471 inhibits >90 % progression of NCI-H446 in a mouse xenograft model. These results suggest that targeting Aurora kinases may be a potential therapeutic strategy to combat the CSC subpopulation in SCLC. Citation Format: Chun-Ping Chang, Yi-Yu Ke, Wen-Hsing Lin, Dai-Hui Jhuo, Wan-Ping Wang, Chia-Hua Tsai, Yen-Ting Chen, Yu-Jie Su, Ming-Chun Hung, Zhong-Wei Wu, Po-Chu Kuo, Teng-Kuang Yeh, Ching-Ping Chen, Jen-Shin Song, Chiun-Tong Chen, Chuan Shih, Ya-Hui Chi. An Aurora kinase inhibitor BPR6K471 inhibits tumor growth and reduces the cancer stem cell-like properties of small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3851.

Ligand efficiency (LE) and lipophilic efficiency (LipE) are two important indicators of "drug-likeness", which are dependent on the molecule's activity and physicochemical properties. We recently reported a furano-pyrimidine Aurora kinase inhibitor 4 (LE = 0.25; LipE = 1.75), with potent activity in vitro; however, 4 was inactive in vivo. On the basis of insights obtained from the X-ray co-crystal structure of the lead 4, various solubilizing functional groups were introduced to optimize both the activity and physicochemical properties. Emphasis was placed on identifying potential leads with improved activity as well as better LE and LipE by exercising tight control over the molecular weight and lipophilicity of the molecules. Rational optimization has led to the identification of Aurora kinase inhibitor 27 (IBPR001; LE = 0.26; LipE = 4.78), with improved in vitro potency and physicochemical properties, resulting in an in vivo active (HCT-116 colon cancer xenograft mouse model) anticancer agent.

Wheatgrass is one of the most widely used health foods, but its functional components and mechanisms remain unexplored. Herein, wheatgrass-derived oligosaccharides (WG-PS3) were isolated and found to induce CD69 and Th1 cytokine expression in human peripheral blood mononuclear cells. In particular, WG-PS3 directly activated the purified monocytes by inducing the expression of CD69, CD80, CD86, IL-12, and TNF-α but affected NK and T cells only in the presence of monocytes. After further purification and structural analysis, maltoheptaose was identified from WG-PS3 as an immunomodulator. Maltoheptaose activated monocytes via Toll-like receptor 2 (TLR-2) signaling, as discovered by pretreatment of blocking antibodies against Toll-like receptors (TLRs) and also determined by click chemistry. This study is the first to reveal the immunostimulatory component of wheatgrass with well defined molecular structures and mechanisms.

μ-Opioid receptor (MOR) agonists are analgesics used clinically for the treatment of moderate to severe pain, but their use is associated with severe adverse effects such as respiratory depression, constipation, tolerance, dependence, and rewarding effects. In this study, we identified N-({2-[(4-bromo-2-trifluoromethoxyphenyl)sulfonyl]-1,2,3,4-tetrahydro-1-isoquinolinyl}methyl)cyclohexanecarboxamide (1) as a novel opioid receptor agonist by high-throughput screening. Structural modifications made to 1 to improve potency and blood-brain-barrier (BBB) penetration resulted in compounds 45 and 46. Compound 45 was a potent MOR/KOR (κ-opioid receptor) agonist, and compound 46 was a potent MOR and medium KOR agonist. Both 45 and 46 demonstrated a significant anti-nociceptive effect in a tail-flick test performed in wild type (WT) B6 mice. The ED50 value of 46 was 1.059 mg/kg, and the brain concentrations of 45 and 46 were 7424 and 11696 ng/g, respectively. Accordingly, compounds 45 and 46 are proposed for lead optimization and in vivo disease-related pain studies.

The functional components in soymilk may vary depending upon the fermentation process. A fermented soymilk product (FSP) obtained by incubation with the microorganisms of intestinal microflora was found to reduce the risk of breast cancer. Guided by the inhibitory activities against breast cancer cells, two cytotoxic compounds, daidzein and (S)-latifolicinin A, were isolated from the FSP by repetitive extraction and chromatography. Latifolicinin A is the n-butyl ester of β-(4-hydroxyphenyl)lactic acid (HPLA). A series of the ester and amide derivatives of (S)-HPLA and L-tyrosine were synthesized for evaluation of their cytotoxic activities. In comparison, (S)-HPLA derivatives exhibited equal or superior inhibitory activities to their L-tyrosine counterparts, and (S)-HPLA amides showed better cytotoxic activities than their corresponding esters. In particular, (S)-HPLA farnesyl amide was active to triple-negative MDA-MB-231 breast cancer cells (IC50 = 27 μM) and 10-fold less toxic to Detroit-551 normal cells.

The human immunodeficiency virus type 1 (HIV-1)-encoded RNA-binding protein Tat is known to play an essential role in viral gene expression. In the search for novel compounds to inhibit Tat transactivity, one coumarin derivative, BPRHIV001, was identified, with a 50% effective concentration (EC 50 ) against HIV-1 at 1.3 nM. BPRHIV001 is likely to exert its effects at the stage after initiation of RNAPII elongation since Tat protein expression and the assembly of the Tat/P-TEFb complex remained unchanged. Next, a reduction of the p300 protein level, known to modulate Tat function through acetylation, was observed upon BPRHIV001 treatment, while the p300 mRNA level was unaffected. A concordant reduction of phosphorylated Akt, which was shown to be closely related to p300 stability, was observed in the presence of BPRHIV001 and was accompanied by a decrease of phosphorylated PDPK1, a well-known Akt activator. Furthermore, the docking analysis revealed that the reduced PDPK1 phosphorylation likely resulted from the allosteric effect of interaction between BPRHIV001 and PDPK1. With strong synergistic effects with current reverse transcriptase inhibitors, BPRHIV001 has the potential to become a promising lead compound for the development of a novel therapeutic agent against HIV-1 infection.

Head and neck squamous cell carcinoma (HNSCC), the most common malignant neoplasm arising in the mucosa of the upper aerodigestive tract, remains a significant cause of morbidity worldwide. With respect to the cancer treatment, HNSCC has a moderately good survival rate, however, the disease often recurs, leading to a poor prognostic disease course and tends to fail in treatment. The metabolic properties of cancer cells diverge significantly from those of normal cells. Emerging evidence suggests these metabolic alterations are also linked to therapeutic resistance in cancer treatment. EGFR targeted agents currently approved or under investigation for HNSCC. We recently identified a novel EGFR tyrosine kinase inhibitor (EGFR-TKI), BPR3K007S0, and found that this compound significantly inhibited EGFR phosphorylation in EGFR-overexpressing HNSCC cells in vitro and in vivo than that of gefitinib. BPR3K007S0 significantly suppressed the expression of a wide range of metabolic genes, including metabolic-related transcription factors, glycolysis, TCA cycle, and pentose phosphate pathway genes. Collectively, we also found that BPR3K007S0 significantly decreased glycolytic and mitochondria respiratory capacity. Pharmacological and genetic manipulation demonstrated that c-Myc/hexokinase 2 axis was one of downstream effector in response to EGFR inhibition. Furthermore, we found that EGFR-TKIs were able to suppress succinate dehydrogenase A leading to reduce fumarate, an oncometabolite generates from Kreb cycle, and contributed to EGFR-TKIs mediated antitumor effect. Taken together, these results revealed that blockage of EGFR signaling repurposes tumor metabolism through suppression of hexokinase 2 and succinate dehydrogenase A, in glycolysis and Kreb cycle, respectively, and demonstrated added benefits to treatment of HNSCCs. Citation Format: Ching-Chuan Kuo, Jang-Yang Chang, Hsing-Pang Hsieh, Hsing-Jien Kung, Hsih-Huei Chang, Chih-Hsiang Huang, Cheng-Chin Kuo, Yi-Yu Ke. Blockage of EGFR signaling repurposes tumor metabolism through suppression of glycolysis and Kreb cycle in head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3944.

The inhibition of FMS-like tyrosine kinase 3 (FLT3) activity using small-molecule inhibitors has emerged as a target-based alternative to traditional chemotherapy for the treatment of acute myeloid leukemia (AML). In this study, we report the use of structure-based virtual screening (SBVS), a computer-aided drug design technique for the identification of new chemotypes for FLT3 inhibition. For this purpose, homology modeling (HM) of the DFG-in FLT3 structure was carried using two template structures, including PDB ID: 1RJB (DFG-out FLT3 kinase domain) and PDB ID: 3LCD (DFG-in CSF-1 kinase domain). The modeled structure was able to correctly identify known DFG-in (SU11248, CEP-701 and PKC-412) and DFG-out (sorafenib, ABT-869 and AC220) FLT3 inhibitors, in docking studies. The modeled structure was then used to carry out SBVS of an HTS library of 125,000 compounds. The top scoring 97 compounds were tested for FLT3 kinase inhibition and two hits (BPR056, IC50 = 2.3 and BPR080, IC50 = 10.7 μM) were identified. Molecular dynamics simulation and density functional theory calculation suggest that BPR056 (MW: 325.32; cLogP: 2.48) interacted with FLT3 in a stable manner and could be chemically optimized to realize a drug-like lead in the future.

Guided by computational modeling addressing the back pocket of Aurora kinases, several novel chemical analogs of BPR1K653 were designed and synthesized in two steps with 30-66% yields. All synthesized compounds were evaluated by Aurora-A and Aurora-B enzymatic kinase activity assays, cellular phosphorylation inhibition assays and cell viability assays. Of them, compound 3a that exhibits no substitution at phenylurea showed similar inhibition activity to Aurora-A and -B. Compounds 3b and 3c which harbor tertiary amino group at meta position of phenylurea showed 10-15 fold inhibition selectivity for Aurora-A over Aurora-B in enzymatic assays. In addition, 3b and 3c were more than 200 fold superior in inhibiting T-loop autophosphorylation of Aurora-A compared to Aurora-B in HCT116 colon carcinoma cells. On the other hand, compound 3d with a 4-hydroxypiperidinyl group at ortho position preserves Aurora-B inhibition activity. Molecular docking study revealed that the various steric interaction between the compound and residues in the back pocket of Aurora kinases determines their inhibition selectivity. Citation Format: Ya-Hui Chi, Chun-Ping Chang, Yi-Yu Ke, Wen-Hsing Lin, Hsing-Pang Hsieh. Design and synthesis of BPR1K653 and its derivatives targeting the back pocket of Aurora kinases for selective isoform inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3233. doi:10.1158/1538-7445.AM2017-3233

We describe the 3D-QSAR-assisted design of an Aurora kinase A inhibitor with improved physicochemical properties, in vitro activity, and in vivo pharmacokinetic profiles over those of the initial lead. Three different 3D-QSAR models were built and validated by using a set of 66 pyrazole (Model I) and furanopyrimidine (Model II) compounds with IC(50) values toward Aurora kinase A ranging from 33 nM to 10.5 μM. The best 3D-QSAR model, Model III, constructed with 24 training set compounds from both series, showed robustness (r(2) (CV) =0.54 and 0.52 for CoMFA and CoMSIA, respectively) and superior predictive capacity for 42 test set compounds (R(2) (pred) =0.52 and 0.67, CoMFA and CoMSIA). Superimposition of CoMFA and CoMSIA Model III over the crystal structure of Aurora kinase A suggests the potential to improve the activity of the ligands by decreasing the steric clash with Val147 and Leu139 and by increasing hydrophobic contact with Leu139 and Gly216 residues in the solvent-exposed region of the enzyme. Based on these suggestions, the rational redesign of furanopyrimidine 24 (clog P=7.41; Aurora A IC(50) =43 nM; HCT-116 IC(50) =400 nM) led to the identification of quinazoline 67 (clog P=5.28; Aurora A IC(50) =25 nM; HCT-116 IC(50) =23 nM). Rat in vivo pharmacokinetic studies showed that 67 has better systemic exposure after i.v. administration than 24, and holds potential for further development.