Drug Discovery against Psoriasis: Identification of a New Potent FMS-like Tyrosine Kinase 3 (FLT3) Inhibitor, 1-(4-((1H-Pyrazolo[3,4-d]pyrimidin-4-yl)oxy)-3-fluorophenyl)-3-(5-(tert-butyl)isoxazol-3-yl)urea, That Showed Potent Activity in a Psoriatic Animal Model

An overview of small-molecule agents for the treatment of psoriasis

Psoriasis is a prevalent, chronic inflammatory disease characterized by abnormal skin plaques. To date, physical therapy, topical therapy, systemic therapy and biologic drugs are the most commonly employed strategies for treating psoriasis. Recently, many agents have advanced to clinical trials, and some anti-psoriasis drugs have been approved, including antibody drugs and small-molecule drugs. Many antibody drugs targeting cytokines and receptors, such as interleukin (IL-17 and IL-23) and tumor necrosis factor-α (TNF-α), have been approved for the treatment of psoriasis. And numerous small-molecule agents have displayed promising activities in the treatment of psoriasis. The targets of anti-psoriasis drugs encompass phosphodiesterase IV (PDE4), Janus kinase (JAK), tyrosine kinase (TYK), retinoic acid-related orphan receptors (ROR), vitamin D receptor (VDR), Interleukin (IL), Aryl hydrocarbon receptor (AhR), Interleukin-1 receptor-associated kinase 4 (IRAK), chemoattractant-like receptor 1 (ChemR23), Sphingosine-1-phosphate receptor (S1P), A3 adenosine receptor (A3AR), Heat shock protein 90 (HSP90), The Rho-associated protein kinases (ROCK), The bromodomain and extra-terminal domain (BET), FMS-like tyrosine kinase 3 (FLT3), Tumor Necrosis Factor α Converting Enzyme (TACE), Toll-like receptors (TLR), NF-κB inducing kinase (NIK), DNA topoisomerase I (Topo I), among others. Herein, this review mainly recapitulates the advancements in the structure and enzyme activity of small-molecule anti-psoriasis agents over the last ten years, and their binding modes were also explored. Hopefully, this review will facilitate the development of novel small-molecule agents as potential anti-psoriasis drugs.

Discovery of novel phenyl urea SHP2 inhibitors with anti-colon cancer and potential immunomodulatory effects

Src Homology-2 Domain Containing Protein Tyrosine Phosphatase-2 (SHP2) is a non-receptor-type protein tyrosine phosphatase (PTP), which is recognized as potential and attractive cancer therapeutic target. Currently, no SHP2 inhibitors have been approved for clinical use, and colorectal cancer (CRC) cells exhibited frequent resistance to reported SHP2 inhibitors, such as SHP099 and TNO155. Herein, we reported our discovery and optimization of phenyl urea as novel SHP2 inhibitors. A8, the most potential SHP2 inhibitor, exhibited great antiproliferative activities against SHP099/TNO155-insensitive tumor cell lines, and rescued PD-L1-mediated immunosuppression. A8 significantly suppressed in vivo tumor growth in a CT26 mouse model and activated immunomodulatory effects in tumor microenvironment. Our work demonstrated that A8 has the potential to be a lead compound for the further development of SHP2 inhibitor and the treatment of CRC.

The Expression of Cytokines and Chemokines Potentially Distinguishes Mild and Severe Psoriatic Non-Lesional and Resolved Skin from Healthy Skin and Indicates Different Stages of Inflammation

In the psoriatic non-lesional (PS-NL) skin, the tissue environment potentially influences the development and recurrence of lesions. Therefore, we aimed to investigate mechanisms involved in regulating tissue organization in PS-NL skin. Cytokine, chemokine, protease, and protease inhibitor levels were compared between PS-NL skin of patients with mild and severe symptoms and healthy skin. By comparing mild and severe PS-NL vs. healthy skin, differentially expressed cytokines and chemokines suggested alterations in hemostasis-related processes, while protease inhibitors showed no psoriasis severity-related changes. Comparing severe and mild PS-NL skin revealed disease severity-related changes in the expression of proteases, cytokines, and chemokines primarily involving methyl-CpG binding protein 2 (MECP2) and extracellular matrix organization-related mechanisms. Cytokine and chemokine expression in clinically resolved versus healthy skin showed slight interleukin activity, differing from patterns in mild and severe PS-NL skin. Immunofluorescence analysis revealed the severity-dependent nuclear expression pattern of MECP2 and decreased expression of 5-methylcytosine and 5-hydroxymethylcytosine in the PS-NL vs. healthy skin, and in resolved vs. healthy skin. Our results suggest distinct cytokine-chemokine signaling between the resolved and PS-NL skin of untreated patients with varying severities. These results highlight an altered inflammatory response, epigenetic regulation, and tissue organization in different types of PS-NL skin with possibly distinct, severity-dependent para-inflammatory states.

Artemisia monosperma essential oil nanoformulations alleviate imiquimod-induced psoriasis-like dermatitis in mice

Psoriasis is an inflammatory immune-mediated skin disease that affects nearly 2-3 % of the global population. The current study aimed to develop safe and efficient anti-psoriatic nanoformulations from Artemisia monosperma essential oil (EO). EO was extracted using hydrodistillation (HD), microwave-assisted hydrodistillation (MAHD), and head-space solid-phase microextraction (HS-SPME), as well as GC/ MS was used for its analysis. EO nanoemulsion (NE) was prepared using the phase inversion method, while the biodegradable polymeric film (BF) was prepared using the solvent casting technique. A.monosperma EO contains a high percentage of non-oxygenated compounds, being 90.45 (HD), 82.62 (MADH), and 95.17 (HS-SPME). Acenaphthene represents the major aromatic hydrocarbon in HD (39.14 %) and MADH (48.60 %), while sabinene as monoterpene hydrocarbon (44.2 %) is the primary compound in the case of HS-SPME. The anti-psoriatic Effect of NE and BF on the successful delivery of A.monosperma EO was studied using the imiquimod (IMQ)-induced psoriatic model in mice. Five groups (n = 6 mice) were classified into control group, IMQ group, IMQ+standard group, IMQ+NE group, and IMQ+BF group. NE and BF significantly alleviated the psoriatic skin lesions and decreased the psoriasis area severity index, Baker's score, and spleen index. Also, they reduced the expression of Ki67 and attenuated the levels of tumor necrosis factor-alpha, interleukin 6, and interleukin 17. Additionally, NE and NF were able to downregulate the NF-κB and GSK-3β signaling pathways. Despite the healing properties of BF, NE showed a more prominent effect on treating the psoriatic model, which could be referred to as its high skin penetration ability and absorption. These results potentially contribute to documenting experimental and theoretical evidence for the clinical uses of A.monosperma EO nanoformulations for treating psoriasis.

Small-molecule agents for treating skin diseases

Skin diseases are a class of common and frequently occurring diseases that significantly impact daily lives. Currently, the limited effective therapeutic drugs are far from meeting the clinical needs; most drugs typically only provide symptomatic relief rather than a cure. Developing small-molecule drugs with improved efficacy holds paramount importance for treating skin diseases. This review aimed to systematically introduce the pathogenesis of common skin diseases in daily life, list related drugs applied in the clinic, and summarize the clinical research status of candidate drugs and the latest research progress of candidate compounds in the drug discovery stage. Also, it statistically analyzed the number of publications and global attention trends for the involved skin diseases. This review might provide practical information for researchers engaged in dermatological drugs and further increase research attention to this disease area.

Design, synthesis, and biological evaluation with molecular dynamics study of novel pyrazolo[3,4-d]pyrimidine derivatives as anti-cancer agents

In continuation of our efforts to discover new structural chemotypes with significant chemotherapeutic activities, a novel series of pyrazolo[3,4-d]pyrimidine-based compounds linked to a piperazine ring, bearing different aromatic moieties, through different linkages was designed and synthesized as FLT3 inhibitors. All of the newly synthesized compounds were evaluated for their cytotoxicity on 60-NCI cell lines. Compounds with the piperazine acetamide linkage XIIa-f & XVI exhibited a remarkable anticancer activity among all of the tested compounds, especially against non-small cell lung cancer, melanoma, leukemia and renal cancer models. Furthermore, compound XVI (NSC no - 833644) was further screened with a 5-dose assay on nine subpanels and exhibited a GI₅₀ between 1.17 and 18.40 μM. On the other hand, molecular docking and dynamics studies were performed to predict the binding mode of the newly synthesized compounds in the FLT3 binding domain. Finally, through a predictive kinetic study, several ADME descriptors were calculated.

Rational Design, Synthesis, and Biological Evaluation of Fluorine- and Chlorine-Substituted Pyrazol-5-yl-benzamide Derivatives as Potential Succinate Dehydrogenase Inhibitors

To develop novel succinate dehydrogenase inhibitors (SDHIs), two series of novel N-4-fluoro-pyrazol-5-yl-benzamide and N-4-chloro-pyrazol-5-yl-benzamide derivatives were designed and synthesized, and their antifungal activities were evaluated against Valsa mali, Sclerotinia sclerotiorum, FusaHum graminearum Sehw, Physalospora piricola, and Botrytis cinerea. The bioassay results showed that some of the target compounds exhibited good antifungal activities in vitro against V. mali and S. sclerotiorum. Remarkably, compound 9Ip displayed good in vitro activity against V. mali with an EC₅₀ value of 0.58 mg/L. This outcome was 21-fold greater than that of fluxapyroxad (12.45 mg/L) and close to that of the commercial fungicide tebuconazole (EC₅₀ = 0.36 mg/L). In addition, in vivo experiments proved that compound 9Ip has good protective fungicidal activity with an inhibitory rate of 93.2% against V. mali at 50 mg/L, which was equivalent to that of the positive control tebuconazole (95.5%). The results of molecular docking indicated that there were obvious hydrogen bonds and p-π interactions between compound 9Ip and succinate dehydrogenase (SDH), which could explain the probable action mechanism. In addition, the SDH enzymatic inhibition assay was carried out to further prove its mode of action. Our studies suggest that compound 9Ip could be a fungicidal lead to discover more potent SDHIs for crop protection.

P. granatum Peel Polysaccharides Ameliorate Imiquimod-Induced Psoriasis-Like Dermatitis in Mice via Suppression of NF-κB and STAT3 Pathways

Psoriasis is a chronic and refractory inflammatory and autoimmune-mediated cutaneous disease affecting approximately 2%–3% of the global population. Most of the current therapies could relieve symptoms rapidly, while the side effects cannot be negligible. Hence, it is urgent to explore much safer and more effective treatments. In the current work, we evaluated the potential beneficial effect of Punica granatum peel polysaccharides (PPPs) in an imiquimod-elicited psoriasis-like mouse model and unraveled their mechanism of action. Firstly, PPPs were isolated from P. granatum peels, and then the molecular weight was determined and monosaccharide analysis was performed. The results revealed that PPPs significantly ameliorated psoriasis-like skin lesions and reduced the Psoriasis Area and Severity Index (PASI) scores and transepidermal water loss (TEWL). PPPs also attenuated the expressions of CD3 and Ki67 in psoriasis-like mouse skin and suppressed the serum or skin levels of pro-inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), IL-1β, IL-8, IL-17, and IL-23. Moreover, PPPs were able to upregulate the mRNA and protein expressions of aquaporin-3 (AQP3) and filaggrin (FLG) in the skin of mice. In addition, PPPs inhibited the NF-κB and STAT3 signaling pathways. Overall, these results indicated that PPPs ameliorated the symptoms of psoriasis through inhibition of the inflammatory cytokines by suppressing the NF-κB and STAT3 signaling pathways and improved skin barrier protection via enhancing AQP3 and FLG. These observations potentially contribute to providing theoretical and experimental evidence for the clinical application of PPPs for psoriasis.

ProfKin: A comprehensive web server for structure-based kinase profiling

Protein kinases are central mediators of signal-transduction cascades and attractive drug targets for therapeutic intervention. Since kinases are structurally and mechanistically related to each other, kinase inhibitor selectivity is often investigated by kinase profiling and considered as an important index for drug discovery. We here describe a versatile web server termed ProfKin for structure-based kinase profiling, which is based on a kinase-ligand focused database (KinLigDB). It provides all ready-to-use 3D structure coordinates of 4219 kinase-ligand complex structures covering 297 human kinases and the associated information, particularly including binding site type, binding ligand type, interaction fingerprints, downstream molecules and related human diseases. The web server works via predicting possible binding modes for the query molecule, prioritizing the binding modes guided by an interaction fingerprint analysis method, and giving a list of ranked kinases by a comprehensive index. Users can freely select entire or part of the KinLigDB database, e.g. via subfamily and binding site type, to customize the profiling contents. The superimpositions of the predicted binding poses of the query molecule with reference binding modes can be visually inspected on the website. The additional classification attributes and phylogenetic tree are also given for each top-ranked kinase.

Galangin ameliorates Imiquimod-Induced psoriasis-like skin inflammation in BALB/c mice via down regulating NF-κB and activation of Nrf2 signaling pathways

Psoriasis is a most common chronic autoimmune-arbitrated cutaneous inflammatory skin disorder by unclear pathogenesis. In this current study we demonstrated the effect of galangin (GAL) on imiquimod (IMQ)-induced psoriasis-like skin inflammation and decipher its possible protective mechanism which has not been investigated. The in vivo results revealed that GAL at 1% w/w and 2% w/w for six consecutive days markedly reduced IMQ-induced PASI scoring, skin, ear thickness, hematological markers, levels of nitrites, TBARS, MPO, histopathological, as well modulated the protein levels of pro-inflammatory mediators of COX-2, iNOS, NF-κB pathway and pro-inflammatory cytokines IL-17, IL-23, IL-1β in the skin and also IL-6, TNF-α in both skin and serum. Besides, GAL restored the levels of antioxidants markers such as SOD, CAT, GST, GSH, GR and Vit-C, anti-inflammatory cytokine of IL-10, and the protein levels of Nrf2/HO-1 in the skin compared to the IMQ group. Finally, our study demonstrates that GAL exerted its protective effect by up-regulating the anti-inflammatory and the antioxidant markers against psoriasis pre-clinical models indicating its potency for treating psoriasis in humans.

X-ray Structure-Guided Discovery of a Potent, Orally Bioavailable, Dual Human Indoleamine/Tryptophan 2,3-Dioxygenase (hIDO/hTDO) Inhibitor That Shows Activity in a Mouse Model of Parkinson's Disease

Human indoleamine 2,3-dioxygenase 1 (hIDO1) and tryptophan 2,3-dioxygenase (hTDO) have been closely linked to the pathogenesis of Parkinson's disease (PD); nevertheless, development of dual hIDO1 and hTDO inhibitors to evaluate their potential efficacy against PD is still lacking. Here, we report biochemical, biophysical, and computational analyses revealing that 1H-indazole-4-amines inhibit both hIDO1 and hTDO by a mechanism involving direct coordination with the heme ferrous and ferric states. Crystal structure-guided optimization led to 23, which manifested IC50 values of 0.64 and 0.04 μM to hIDO1 and hTDO, respectively, and had good pharmacokinetic properties and brain penetration in mice. 23 showed efficacy against the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse motor coordination deficits, comparable to Madopar, an anti-PD medicine. Further studies revealed that different from Madopar, 23 likely has specific anti-PD mechanisms involving lowering IDO1 expression, alleviating dopaminergic neurodegeneration, reducing inflammatory cytokines and quinolinic acid in mouse brain, and increasing kynurenic acid in mouse blood.

Synthesis and Biological Activity of Novel Pyrazol-5-yl-benzamide Derivatives as Potential Succinate Dehydrogenase Inhibitors

To promote the discovery and development of new fungicides, a series of novel pyrazol-5-yl-benzamide derivatives were designed, synthesized by hopping and inversion of amide groups of pyrazole-4-carboxamides, and evaluated for their antifungal activities. The bioassay data revealed that compound 5IIc exhibited an excellent in vitro activity against Sclerotinia sclerotiorum with an EC₅₀ value of 0.20 mg/L, close to that of commercial fungicide Fluxapyroxad (EC₅₀ = 0.12 mg/L) and Boscalid (EC₅₀ = 0.11 mg/L). For Valsa mali, compound 5IIc (EC₅₀ = 3.68 mg/L) showed a significantly higher activity than Fluxapyroxad (EC₅₀ = 12.67 mg/L) and Boscalid (EC₅₀ = 14.83 mg/L). In addition, in vivo experiments proved that compound 5IIc has an excellent protective fungicidal activity with an inhibitory rate of 97.1% against S. sclerotiorum at 50 mg/L, while the positive control Fluxapyroxad showed a 98.6% inhibitory effect. The molecular docking simulation revealed that compound 5IIc interact with TRP173, SER39, and ARG43 of succinate dehydrogenase (SDH) through a hydrogen bond and p-π interaction, which could explain the probable mechanism of the action between compound 5IIc and target protein. Also, the SDH enzymatic inhibition assay was carried out to further validate its mode of action. These results demonstrate that compound 5IIc could be a promising fungicide candidate and provide a valuable reference for further investigation.

Studies on the anti-psoriasis effects and its mechanism of a dual JAK2/FLT3 inhibitor flonoltinib maleate

Psoriasis is a chronic, inflammatory autoimmune disease mediated by T cells, and characterized with abnormal proliferation and differentiation of keratinocytes, and inflammatory infiltration. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway has been identified to play essential roles in mediating various of biological processes, and is closely related to autoimmune diseases. Dendritic cells (DCs) are important antigen presenting cells and play an important regulatory role in T cells. The proliferation, differentiation and function of DCs are regulated by JAK and FMS-like tyrosine kinase 3 (FLT3) signal pathways. Flonoltinib maleate (FM), a high selectivity dual JAK2/FLT3 inhibitor with IC50 values of 0.8 nM and 15 nM for JAK2 and FLT3, respectively, was developed by our laboratory. Moreover, FM was a potent JAK2 inhibitor with 863-fold and 696-fold selectivity over JAK1 and JAK3, respectively. In this study, the anti-psoriasis activity of FM was evaluated both in vitro and in vivo. FM effectively inhibited the proliferation of HaCaT, the inflammatory keratinocyte induced by M5 and markedly suppressed the generation and differentiation of DCs from bone marrow (BM), and inhibited the expression of FLT3 in DCs in vitro. FM effectively inhibited the ear thickening and improved the pathological changes of the ear in interleukin (IL)-23-induced psoriasis-like acanthosis mouse model. Further in keratin 14-vascular endothelial growth factor (K14-VEGF) transgenic homozygous mice model, FM could obviously improve the psoriatic symptom and pathological changes, significantly inhibit the generations of Th1 and Th17 cells in the spleen, and the accumulations of DCs in the ears. FM could also significantly reduce the expression of various inflammatory factors both in C57BL/6 and K14-VEGF mice ears, and the serum of K14-VEGF mice. Mechanism revealed that FM effectively suppressed the phosphorylation of JAK2, STAT3 and STAT5 in inflammatory keratinocytes and the mice ears of C57BL/6 and K14-VEGF, as well as the phosphorylation of FLT3 in K14-VEGF mice ears. In conclusion, FM plays an excellent anti-psoriasis activity, including inhibiting keratinocyte proliferation and regulating inflammatory response through inhibiting JAK2 and FLT3 signaling pathway.

Small-Molecule Kinase Inhibitors for the Treatment of Nononcologic Diseases

Great successes have been achieved in developing small-molecule kinase inhibitors as anticancer therapeutic agents. However, kinase deregulation plays essential roles not only in cancer but also in almost all major disease areas. Accumulating evidence has revealed that kinases are promising drug targets for different diseases, including cancer, autoimmune diseases, inflammatory diseases, cardiovascular diseases, central nervous system disorders, viral infections, and malaria. Indeed, the first small-molecule kinase inhibitor for treatment of a nononcologic disease was approved in 2011 by the U.S. FDA. To date, 10 such inhibitors have been approved, and more are in clinical trials for applications other than cancer. This Perspective discusses a number of kinases and their small-molecule inhibitors for the treatment of diseases in nononcologic therapeutic fields. The opportunities and challenges in developing such inhibitors are also highlighted.

Transcriptomic landscaping of core genes and pathways of mild and severe psoriasis vulgaris

Psoriasis is a common chronic inflammatory skin disease affecting >125 million individuals worldwide. The therapeutic course for the disease is generally designed upon the severity of the disease. In the present study, the gene expression profile GSE78097, was retrieved from the National Centre of Biotechnology (NCBI)‑Gene Expression Omnibus (GEO) database to explore the differentially expressed genes (DEGs) in mild and severe psoriasis using the Affy package in R software. The Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways of the DEGs were analysed using clusterProfiler, Bioconductor, version 3.8. In addition, the STRING database was used to develop DEG‑encoded proteins and a protein‑protein interaction network (PPI). Cytoscape software, version 3.7.1 was utilized to construct a protein interaction association network and analyse the interaction of the candidate DEGs encoding proteins in psoriasis. The top 2 hub genes in Cytohubba plugin parameters were validated using immunohistochemical analysis in psoriasis tissues. A total of 382 and 3,001 dysregulated mild and severe psoriasis DEGs were reported, respectively. The dysregulated mild psoriasis genes were enriched in pathways involving cytokine‑cytokine receptor interaction and rheumatoid arthritis, whereas cytokine‑cytokine receptor interaction, cell cycle and cell adhesion molecules were the most enriched pathways in severe psoriasis group. PL1N1, TLR4, ADIPOQ, CXCL8, PDK4, CXCL1, CXCL5, LPL, AGT, LEP were hub genes in mild psoriasis, whereas BUB1, CCNB1, CCNA2, CDK1, CDH1, VEGFA, PLK1, CDC42, CCND1 and CXCL8 were reported hub genes in severe psoriasis. Among these, CDC42, for the first time (to the best of our knowledge), has been reported in the psoriasis transcriptome, with its involvement in the adaptive immune pathway. Furthermore, the immunoexpression of CDK1 and CDH1 proteins in psoriasis skin lesions were demonstrated using immunohistochemical analysis. On the whole, the findings of the present integrated bioinformatics and immunohistochemical study, may enhance our understanding of the molecular events occurring in psoriasis, and these candidate genes and pathways together may prove to be therapeutic targets for psoriasis vulgaris.

Discovery of small molecule FLT3 inhibitors that are able to overcome drug-resistant mutations

Herein we report the discovery of 1-(5-(tert-butyl)isoxazol-3-yl)-3- (3-fluorophenyl)urea derivatives as new FLT3 inhibitors that are able to overcome the drug resistance mutations: the secondary D835Y and F691L mutations on the basis of the internal tandem duplications (ITD) mutation of FLT3 (FLT3-ITD/D835Y and FLT3-ITD/F691L, respectively). The most potent compound corresponds to 1-(5-(tert-butyl)isoxazol-3-yl)-3-(4-((6,7-dimethoxyquinolin-4-yl)oxy)-3- fluorophenyl)urea (4d), which showed IC₅₀s (half maximal inhibitory concentrations) of 0.072 nM, 5.86 nM and 3.48 nM against FLT3-ITD, FLT3-ITD/F691L and FLT3-ITD/D835Y, respectively. Compound 4d also showed good selectivity for FLT3 in a kinase profiling assay. Collectively, 4d could be a good lead compound and deserves further in-depth studies.

Recent advances in FLT3 inhibitors for acute myeloid leukemia

Fms-like tyrosine kinase-3 (FLT3) mutations occur in approximately 30% of acute myeloid leukemia (AML) cases, suggesting FLT3 as an attractive target for AML treatment. Early FLT3 inhibitors enhance antileukemia efficacy by inhibiting multiple targets, and thus had stronger off-target activity, increasing their toxicity. Recently, a number of potent and selective FLT3 inhibitors have been developed, many of which are effective against multiple mutations. This review outlines the evolution of AML-targeting FLT3 inhibitors by focusing on their chemotypes, selectivity and activity over FLT3 wild-type and FLT3 mutations as well as new techniques related to FLT3. Compounds that currently enter the late clinical stage or have entered the market are also briefly reported.

Urea Derivatives in Modern Drug Discovery and Medicinal Chemistry

The urea functionality is inherent to numerous bioactive compounds, including a variety of clinically approved therapies. Urea containing compounds are increasingly used in medicinal chemistry and drug design in order to establish key drug-target interactions and fine-tune crucial drug-like properties. In this perspective, we highlight physicochemical and conformational properties of urea derivatives. We provide outlines of traditional reagents and chemical procedures for the preparation of ureas. Also, we discuss newly developed methodologies mainly aimed at overcoming safety issues associated with traditional synthesis. Finally, we provide a broad overview of urea-based medicinally relevant compounds, ranging from approved drugs to recent medicinal chemistry developments.

Identification of Pyrrolo[2,3- d]pyrimidine-Based Derivatives as Potent and Orally Effective Fms-like Tyrosine Receptor Kinase 3 (FLT3) Inhibitors for Treating Acute Myelogenous Leukemia

A series of pyrrolo[2,3- d]pyrimidine derivatives were prepared and optimized for cytotoxic activities against FLT3-ITD mutant cancer cells. Among them, compound 9u possessed nanomolar FLT3 inhibitory activities and subnanomolar inhibitory activities against MV4-11 and Molm-13 cells. It also showed excellent inhibitory activities in FLT3-ITD-D835V and FLT3-ITD-F691L cells which were resistant to quizartinib. Furthermore, 9u exhibited over 40-fold selectivity toward FLT3 relative to c-Kit kinase, which might reduce myelosuppression toxicity. Cellular assays demonstrated that 9u inhibited phosphorylated FLT3 and downstream signaling factors and also induced cell cycle arrest in the G₀/G₁ stage and apoptosis in MV4-11 and Molm-13 cells. Oral administration of 9u at 10 mg/kg could achieve rapid tumor extinction in the MV4-11 xenograft model and significantly inhibit the tumor growth in the MOLM-13 xenograft model with a tumor growth inhibitory rate of 96% without obvious toxicity. Additionally, 9u demonstrated high bioavailability ( F = 59.5%) and suitable eliminated half-life time ( T_1/2 = 2.06 h), suggesting that 9u may be a potent candidate for treating acute myelogenous leukemia.

Design, synthesis, and biological evaluation of polo-like kinase 1/eukaryotic elongation factor 2 kinase (PLK1/EEF2K) dual inhibitors for regulating breast cancer cells apoptosis and autophagy

Both PLK1 and EEF2K are serine⁄threonine kinases that play important roles in the proliferation and programmed cell death of various types of cancer. They are highly expressed in breast cancer tissues. Based on the multiple-complexes generated pharmacophore models of PLK1 and homology models of EEF2K, the integrated virtual screening is performed to discover novel PLK1/EEF2K dual inhibitors. The top ten hit compounds are selected and tested in vitro, and five of them display PLK1 and EEF2K inhibition in vitro. Based on the docking modes of the most potent hit compound, a series of derivatives are synthesized, characterized and biological assayed on the PLK1, EEF2K as well as breast cancer cell proliferation models. Compound 18i with satisfied inhibitory potency are shifted to molecular mechanism studies contained molecular dynamics simulations, cell cycles, apoptosis and autophagy assays. Our results suggested that these novel PLK1/EEF2K dual inhibitors can be used as lead compounds for further development breast cancer chemotherapy.

Structure-based discovery of new maternal embryonic leucine zipper kinase inhibitors

The new MELK inhibitor16showed no inhibitory effect on cancer growth, but can suppress the phosphorylation of focal adhesion kinase, a key kinase in regulating cancer cell migration and invasion.

Discovery of pyrazolo[1,5-a]pyrimidine-3-carbonitrile derivatives as a new class of histone lysine demethylase 4D (KDM4D) inhibitors

Herein we report the discovery of a series of new small molecule inhibitors of histone lysine demethylase 4D (KDM4D). Molecular docking was first performed to screen for new KDM4D inhibitors from various chemical databases. Two hit compounds were retrieved. Further structural optimization and structure-activity relationship (SAR) analysis were carried out to the more selective one, compound 2, which led to the discovery of several new KDM4D inhibitors. Among them, compound 10r is the most potent one with an IC₅₀ value of 0.41±0.03μM against KDM4D. Overall, compound 10r could be taken as a good lead compound for further studies.