Design, synthesis and structure-activity relationship of malonic acid non-nucleoside derivatives as potent CD73 inhibitors.

High levels of extracellular adenosine in tumor microenvironment (TME) has extensive immunosuppressive effect. CD73 catalyzes the conversion of AMP into adenosine and regulates its production. Inhibiting CD73 can reduce the level of adenosine and reverse adenosine-mediated immune suppression. Therefore, CD73 has emerged as a valuable target for cancer immunotherapy. Here, a new series of malonic acid non-nucleoside derivatives were designed, synthesized and evaluated as CD73 inhibitors. Among them, compounds 18 and 19 exhibited significant inhibition activities against hCD73 with IC50 values of 0.28 µM and 0.10 µM, respectively, suggesting the feasibility of replacing the benzotriazole moiety in the lead compound. This study explored the novelty and structural diversity of CD73 inhibitors.

Cross-view contrastive representation learning approach to predicting DTIs via integrating multi-source information.

Drug-target interaction (DTI) prediction serves as the foundation of new drug findings and drug repositioning. For drugs/targets, the sequence data contains the biological structural information, while the heterogeneous network contains the biochemical functional information. These two types of information describe different aspects of drugs and targets. Due to the complexity of DTI machinery, it is necessary to learn the representation from multiple perspectives. We hereby try to design a way to leverage information from multi-source data to the maximum extent and find a strategy to fuse them. To address the above challenges, we propose a model, named MOVE (short for integrating multi-source information for predicting DTI via cross-view contrastive learning), for learning comprehensive representations of each drug and target from multi-source data. MOVE extracts information from the sequence view and the network view, then utilizes a fusion module with auxiliary contrastive learning to facilitate the fusion of representations. Experimental results on the benchmark dataset demonstrate that MOVE is effective in DTI prediction.

Fluorinated plant activators induced dual-pathway signal transduction and long-lasting ROS burst in chloroplast.

Synthetic plant activators represent a promising novel class of green pesticides that can triggering endogenous plant immunity against pathogen invasion. In our previous study, we developed a series of fluorinated compounds capable of eliciting disease resistance in plants; however, the underlying regulatory mechanisms remained unclear. In this study, we systematically investigated the mechanism of plant immune activation using four synthetic plant activators in Arabidopsis thaliana (A. thaliana), including two fluorine-substituted and two non­fluorine-substituted molecules. Our findings revealed that the fluorinated compounds exhibited superior disease resistance activity compared to the non-fluorinated molecules. Gene expression analysis in systemic acquired resistance (SAR)- and induced systemic resistance (ISR)-related pathways demonstrated that fluorine substitution effectively regulated both SAR- and ISR-pathway activation, highlighting the distinct roles of fluorine in modulating the plant immune system. Notably, the prolonged ROS burst was observed in chloroplasts following treatment with all four plant activators, contrasting with the transient ROS burst induced by natural elicitors. These results provide insights into the unique mechanisms underlying synthetic plant activator-induced plant immunity. Furthermore, comprehensive proteomic analysis revealed a robust immune response mediated by fluorine-substituted plant activators. These findings offer novel insights into the role of fluorine substitution in SAR- and ISR-associated immune signaling pathways and their distinct impact on ROS production within chloroplasts.

Binding Free Energy Calculation Based on the Fragment Molecular Orbital Method and Its Application in Designing Novel SHP-2 Allosteric Inhibitors.

The accurate prediction of binding free energy is a major challenge in structure-based drug design. Quantum mechanics (QM)-based approaches show promising potential in predicting ligand-protein binding affinity by accurately describing the behavior and structure of electrons. However, traditional QM calculations face computational limitations, hindering their practical application in drug design. Nevertheless, the fragment molecular orbital (FMO) method has gained widespread application in drug design due to its ability to reduce computational costs and achieve efficient ab initio QM calculations. Although the FMO method has demonstrated its reliability in calculating the gas phase potential energy, the binding of proteins and ligands also involves other contributing energy terms, such as solvent effects, the 'deformation energy' of a ligand's bioactive conformations, and entropy. Particularly in cases involving ionized fragments, the calculation of solvation free energy becomes particularly crucial. We conducted an evaluation of some previously reported implicit solvent methods on the same data set to assess their potential for improving the performance of the FMO method. Herein, we develop a new QM-based binding free energy calculation method called FMOScore, which enhances the performance of the FMO method. The FMOScore method incorporates linear fitting of various terms, including gas-phase potential energy, deformation energy, and solvation free energy. Compared to other widely used traditional prediction methods such as FEP+, MM/PBSA, MM/GBSA, and Autodock vina, FMOScore showed good performance in prediction accuracies. By constructing a retrospective case study, it was observed that incorporating calculations for solvation free energy and deformation energy can further enhance the precision of FMO predictions for binding affinity. Furthermore, using FMOScore-guided lead optimization against Src homology-2-containing protein tyrosine phosphatase 2 (SHP-2), we discovered a novel and potent allosteric SHP-2 inhibitor (compound 8).

A simple monoselective C-H oxygenation approach for the synthesis of ursane triterpenoids.

Herein, we presented a simple approach for C-H oxidation in the C23 or/and C24 of ursane triterpenoids without any protection of a Δ12,13 double bond. As a result, from commercial ursolic acid (UA), six naturally occurring ursane triterpenoids were synthesized in overall yields of 3.4% to 36.8%, which implied the importance of this approach for the derivation of natural products and their application in biological activity.

Design, synthesis and biological evaluation of pteridine-7(8H)-one derivatives as potent and selective CDK4/6 inhibitors.

Cyclin-dependent kinases play an important role in the regulation of cell cycle and transcription. Selective CDK4/6 inhibitors have been demonstrated to be effective in the treatment of cancer. In this article, we described the design and synthesis of a series of pteridine-7(8H)-one derivatives as dual CDK4/6 inhibitors. Among them, the most promising compound L2 exhibited significant inhibitory activity against CDK4 and CDK6 with IC50 values of 16.7 nM and 30.5 nM respectively and showed excellent selectivity to CDK1/2/7/9. Moreover, compound L2 displayed potent antiproliferative activities at low digital micromolar range via inducing apoptosis in breast and colon cancer cells. In all, we developed a new series of pteridine-7(8H)-one derivatives which exhibited promising antitumor activities as selective CDK4/6 inhibitors.

Discovery of pyrido[3,4-b]indol-1-one derivatives as novel non-covalent Bruton's tyrosine kinase (BTK) inhibitors.

Bruton's tyrosine kinase (BTK) is an attractive target for the treatment of malignancy and inflammatory/autoimmune diseases. Most of the covalent BTK inhibitors would induce off-target side effects and drug resistance. To improve the drug safety of BTK inhibitors, non-covalent inhibitors have attracted more and more attention. We designed a series of novel pyrido[3,4-b]indol-1-one derivatives (N-A and N-B) via scaffold hopping from CGI-1746. The structure-activity relationship (SAR) of the newly-synthesized compounds was explored. The results showed that compounds 12 and 18 exhibited potent enzymatic potency against BTK with IC50 values of 0.22 µM and 0.19 µM, respectively. In lymphoma cell lines U-937 cells and Ramos cells, compounds 12 and 18 displayed comparative antiproliferative activity with Ibrutinib. Moreover, compound 12 induced G1-phase cell cycle arrest and apoptosis in U-937 cells. And it could effectively inhibit tumor growth in U-937 xenograft mouse model (TGI = 41.90% at 50 mg/kg). In all, the new pyrido[3,4-b]indol-1-one derivatives have the antitumor potency by BTK inhibition and were worthy of further exploration.

Discovery of pyrrolo[1,2-a]quinoxalin-4(5H)-one derivatives as novel non-covalent Bruton's tyrosine kinase (BTK) inhibitors.

Bruton's tyrosine kinase (BTK) is a promising target in the treatment of B cell malignancies and autoimmune disorders. Developing selective non-covalent BTK inhibitors is an important strategy to overcome the side effects and drug resistance induced by covalent BTK inhibitors. In this article, we designed and synthesized pyrrolo[1,2-a]quinoxalin-4(5H)-one and imidazo[1,2-a]quinoxalin-4(5H)-one based selective noncovalent BTK inhibitors via scaffold hopping from BMS-986142 and investigated their biological activities. Among the synthesized compounds, pyrrolo[1,2-a]quinoxalin-4(5H)-one derivatives 2 and 4 showed great BTK inhibition potency with IC50 value at 7.41 nM and 11.4 nM, respectively. Besides, they showed equivalent or even better potency in U937 and Ramos cells than BMS-986142. The kinase selectivity profiling study illustrated the excellent selectivity of compound 2 against a panel of 468 kinases. In U937 xenograft models, compound 2 could significantly inhibit tumor growth with TGI = 65.61%. In all, we provided a new scaffold as non-covalent selective BTK inhibitors and the representative compounds exhibited potency both in vitro and in vivo.

Design, Synthesis, and Structure-Activity Relationship Study of Potent MAPK11 Inhibitors.

Huntington's disease (HD) is a rare single-gene neurodegenerative disease, which can only be treated symptomatically. Currently, there are no approved drugs for HD on the market. Studies have found that MAPK11 can serve as a potential therapeutic target for HD. Regrettably, no MAPK11 small molecule inhibitors have been approved at present. This paper presents three series of compounds that were designed and synthesized based on the structure of skepinone-L, a known MAPK14 inhibitor. Among the synthesized compounds, 13a and 13b, with IC50 values of 6.40 nM and 4.20 nM, respectively, displayed the best inhibitory activities against MAPK11. Furthermore, the structure-activity relationship (SAR) is discussed in detail, which is constructive in optimizing the MAPK11 inhibitors for better activity and effect against HD.

Discovery and optimization of 2-aminopyridine derivatives as novel and selective JAK2 inhibitors.

Janus kinases (JAKs) including JAK1, JAK2, JAK3, and TYK2 are members of a family of intracellular nonreceptor tyrosine kinases, which have been demonstrated to be critical in the cell signaling pathway and involved in inflammatory diseases and cancer. V617F mutation in JAK2 has been implicated in polycythaemia vera (PV), essential thrombocythaemia (ET) and myelofibrosis (MF). Here, we described the design, synthesis, and biological evaluation of a series of 2-aminopyridine derivatives. The results of enzymatic activity assays supported compound 16m-(R) as a potential and selective JAK2 inhibitor, which exhibited high inhibitory activity with an IC50 of 3 nM against JAK2, and 85- and 76-fold selectivity over JAK1 and JAK3, respectively. Structure-activity relationships (SAR) and mechanistic analysis demonstrated that 16m-(R) might be a promising selective JAK2 inhibitor for further study.

Design, synthesis and biological evaluation of potent EGFR kinase inhibitors against 19D/T790M/C797S mutation.

The efficacy of EGFR inhibitors is frequently affected by acquired resistance. EGFR19D/T790M/C797S mutation is one of the primary reasons for the emergence of resistance after treatment with the third-generation EGFR inhibitors such as AZD9291, CO1686 and Olmutinib. To overcome the resistance mutation 19D/T790M/C797S, we designed and prepared a series of indole derivatives with the terminal hydroxyl of alkyl chain to increase extra interaction with the Asp855 in the conservative DFG site. Activity evaluation, structure-activity relationship and docking analysis were also carried out. Among them, compound 12e displayed significant inhibitory activity against EGFR19D/T790M/C797S (IC50 = 15.3 nM) and good selectivity over EGFR WT (IC50 > 1000 nM), L858R/T790M (IC50, 156.6 nM) and L858R/T790M/C797S (IC50, 218.3 nM) respectively. Furthermore, 12e exhibited good growth inhibition activity, induced G1 phase cell cycle arrest and apoptosis in BaF3/EGFR19D/T790M/C797S cells by suppressing EGFR phosphorylation signaling pathway. In all, our study might provide a novel structural design method and lay the solid foundation for the development of the 4th generation EGFR19D/T790M/C797S inhibitors.

Aurora B kinase as a novel molecular target for inhibition the growth of osteosarcoma.

Osteosarcoma is the primary human malignant tumor affecting bone. This cancer most frequently arises in children and adolescents, with a second peak in those over the age of 50. Currently, surgery followed by radiotherapy and chemotherapy are the main treatments, but long-term positive effects are very poor. Aurora B kinase is a serine/threonine kinase that is a key regulator of cell cycle and mitosis. Tissue array analysis revealed that Aurora B kinase is overexpressed in osteosarcoma compared with normal bone tissue. We developed a compound, HOI-07 (i.e., (E)-3-((E)-4-(benzo[d] [1,3]dioxol-5-yl)-2-oxobut-3-en-1-ylidene)indolin-2-one), as a specific Aurora B kinase inhibitor and examined its effectiveness against osteosarcoma cell growth in this study. This compound inhibited Aurora B kinase activity in osteosarcoma and induced apoptosis, caused G2-M phase arrest, and attenuated osteosarcoma anchorage-independent cell growth. Moreover, knocking down the expression of Aurora B effectively reduced the sensitivity of osteosarcoma to HOI-07. Results of a xenograft mouse study indicated that HOI-07 treatment effectively suppressed the growth of 143B and KHOS xenografts, without affecting the body weight of mice. The expression of phosphorylated histone H3 (Ser10) was reduced in mice treated with HOI-07. Overall, we identified HOI-07 as a specific Aurora B kinase inhibitor for osteosarcoma treatment and this compound warrants further investigation.

Design, synthesis and structure-activity relationship study of aminopyridine derivatives as novel inhibitors of Janus kinase 2.

Janus Kinase 2 (JAK2) is a kind of intracellular non-receptor protein tyrosine kinase and has been certified as an important target for the treatment of myeloproliferative neoplasms and rheumatoid arthritis. However, the low selectivity and potential safety issues restrict the clinical applications of JAK2 inhibitors. Here we found that crizotinib showed good inhibitory activity against JAK2 by enzymatic assays (IC50 = 27 nM). Then we carried out structure-based drug design and synthesized a series of compounds with an aminopyridine scaffold. Finally, compound 12k and 12l were identified as the promising inhibitors of JAK2, which exhibited high inhibitory activity (IC50 = 6 nM and 3 nM, respectively) and selectivity for JAK2 over JAK1 and JAK3, and showed potent antiproliferative activities toward HEL human erythroleukemia cells. Moreover, 12k suppressed symptoms of the collagen-induced arthritis (CIA) model in rats.

Discovery and Biological evaluation of pyrimido[4,5-d]pyrimidine-2,4(1H,3H)-dione derivatives as potent Bruton's tyrosine kinase inhibitors.

Aberrant activation of B cell receptor (BCR) signal transduction cascade contributes to the propagation and maintenance of B cell malignancies. The discovery of mall molecules with high potency and selectivity against Bruton's tyrosine kinase (BTK), a key signaling molecule in this cascade, is particularly urgent in modern treatment regimens. Herein, a series of pyrimido[4,5-d]pyrimidine-2,4(1H,3H)-dione derivatives were reported as potent BTK inhibitors. Compounds 17 and 18 displayed strong BTK inhibitory activities in the enzymatic inhibition assay, with the IC50 values of 1.2 and 0.8 nM, respectively, which were comparable to that of ibrutinib (IC50 = 0.6 nM). Additionally, compound 17 had a more selective profile over EGFR than ibrutinib. According to the putative binding poses, the molecular basis of this series of compounds with respect to potency against BTK and selectivity over EGFR was elucidated. In further experiments at cellular level, compounds 17 and 18 significantly inhibited the proliferation of Ramos and TMD8 cells. And they arrested 75.4% and 75.2% of TMD8 cells in G1 phase, respectively, at the concentration of 1 µM.

Naringenin inhibits migration of breast cancer cells via inflammatory and apoptosis cell signaling pathways.

BACKGROUND: Naringenin, a flavonoid compound, has a wide variety of uses in the pharmaceutical industry for its antioxidant and anti-inflammatory potential. OBJECTIVES: The current experiment aimed to investigate the anticancer effect of naringenin in triple-negative human breast cancer cells (MDA-MR-231) and an animal model with 7,12-dimethylbenz[a] anthracene (DMBA)-induced breast cancer in female rats to determine the mechanisms and molecular targets. METHODS: The cytotoxic effects of naringenin against MDA-MB-231 cells were assessed by MTT assay. Apoptosis and cell cycle alterations were analyzed via flow cytometry. Morphological and biochemical changes in DMBA-induced cancer with naringenin treatment were assayed using our protocol. The potential mechanisms of action were verified via qRT-PCR. RESULTS: Naringenin was found to inhibit cell proliferation in a time- and concentration-dependent manner. This effect was associated with cell cycle arrest at the G0/G1 phase, along with apoptosis and deposition at the sub-G1 phase (75%). Treatment with naringenin reduced tumor incidence (45.55, 40, and 27.67%) and tumor burden (78.7, 35.4, and 1.2 g) in a dose-dependent manner. Naringenin treatment altered the biochemical and antioxidant parameters related to inflammation necessary for anticancer activity. The qRT-PCR studies further confirmed the mitochondrial-mediated apoptotic effects of naringenin. CONCLUSION: On the basis of these results, we can conclude that naringenin exerts an anticancer effect in the MDA-MB-231 cell line that arrests cell development at the G0/G1 phase, and in vivo it alters the mitochondrial-mediated intrinsic pathway responsible for apoptosis.

68Ga tagged dendrimers for molecular tumor imaging in animals.

Dear Editor, Angiogenesis is an essential physiological process that involves formation of new blood vessels from the pre-existing ones and is one of the fundamental processes required for normal growth and development. The ability to non-invasively evaluate angiogenesis might provide new insights into cancer biology pathway. This approach might lead to opportunities to more appropriately select patients likely to respond to anti-angiogenic drugs. Polyamidoamine dendrimers are a member of a versatile, new class of dendritic polymers and are the most well characterized and widely used polymers. In the present study we have utilized them for imaging of a crucial process of angiogenesis in a cancer model of mice. Amongst, several PET radionuclides, there has been a renewed interest in 68Ga for many reasons. Gallium-68 is well suited for use as a radiolabel for PET because of its comparatively shorter half-life of 68min. The emission of two divergent photons per decay allows the construction of three-dimensional images. Furthermore, the advances in generator technology for 68Ga production and its favorable chemistry for radiocomplexation have paved the way for emerging applications of 68Ga radiopharmaceuticals. A recent study reported the blood pharmacokinetics of different generations of PAMAM dendrimers (generations 3-6) derivatized with large chelating ligands to facilitate complexation of gadolinium ions for imaging applications. It was observed that the resulted PAMAM gadolinium complexes cleared from the blood circulation in a biphasic manner (fast component-10min; slow component-1h). The rapid clearance of the dendrimers from blood observed in our study was in accordance with previous observations. The biodistribution studies of 68Ga-DOTA-G4 PAMAM showed the major uptake at an early time interval of 15min in the kidneys. This confirmed that kidneys are the major excretory organs for DOTA conjugated G4 PAMAM dendrimers. The radioactivity in kidneys, as compared with other organs was higher initially and declined with time. A study in the recent past also reported a high uptake of indium-111 (111In)-DOTA analog-PAMAM dendrimer in rats' kidneys, immediately after administration of radioactivity. A considerable amount of radioactivity was also recovered from lungs which were higher in case of 68Ga-DOTA-G4 PAMAM conjugate. Lung is an important component of the reticulo-endothelial system (RES) and thus is involved in the clearance of macromolecules. Additionally, due to its rich vasculature, lungs are likely targets for the location of intravenously injected dendrimer nanoparticles. The animal biodistribution data in tumor bearing mice demonstrated that the tumor uptake (at 1h) of 68Ga-DOTA-G4 PAMAM dendrimer was 0.33%. It has been reported that using higher generation PAMAM dendrimers, magnetic resonance imaging (MRI) agents affect the biodistribution patterns in animal tumor models. Animal PET imaging data showed that maximum tumor to background ratio was obtained at 1h post injection of 68Ga DOTA-G4 PAMAM dendrimer suggesting that the designed nanoprobes could efficiently target tumor tissues and be retained there due to their enhanced permeability and retention (EPR) effect. Dendrimers can achieve passive EPR mediated targeting to a tumor by controlling their size and physicochemical properties. Further, an earlier study reported that branched PAMAM dendrimer showed significantly higher accumulation in ovarian tumor bearing mice than the conventional linear N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer of comparable molecular weight. The use of radiolabeled dendrimers due to their topology, functionality and dimensions has been described as a promising approach for the molecular visualization of tumor angiogenesis. So, the successful radiolabeling of 68Ga-DOTA-G4 PAMAM dendrimers is encouraging as it showed good localization of both the radiolabeled by 68Ga and 111In products in the tumor.

Synthesis, Design, and Structure⁻Activity Relationship of the Pyrimidone Derivatives as Novel Selective Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase.

The inhibition of Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) potentially represents a new treatment option for malaria, as P. falciparum relies entirely on a de novo pyrimidine biosynthetic pathway for survival. Herein, we report a series of pyrimidone derivatives as novel inhibitors of PfDHODH. The most potent compound, 26, showed high inhibition activity against PfDHODH (IC50 = 23 nM), with >400-fold species selectivity over human dihydroorotate dehydrogenase (hDHODH). The brand-new inhibitor scaffold targeting PfDHODH reported in this work may lead to the discovery of new antimalarial agents.

Development of Degraders of Cyclin-Dependent Kinases 4 and 6 Based on Rational Drug Design.

Degradation of target proteins has been considered to be a promising therapeutic approach, but the rational design of compounds for degradation remains a challenge. In this study, we reasonably designed and synthesized only 10 compounds to discover effective CDK4/6 protein degraders. Among the newly synthesized compounds, 7f achieved dual degradation of CDK4/6 protein, with DC50 values of 10.5 and 2.5 nM, respectively. Compound 7f also exhibited inhibitory proliferative activity against Jurkat cells with an IC50 value of 0.18 µM. Furthermore, 7f induced cell apoptosis and G1 phase cell cycle arrest in a dose-dependent manner in Jurkat cells. In conclusion, these findings demonstrate the potential of 7f as a CDK4/6 degrader and a potential therapeutic strategy against cancer, thereby expanding the potential of CDK4/6 dual PROTACs.

Discovery of Novel Non-Nucleoside Inhibitors Interacting with Dizinc Ions of CD73.

High extracellular concentrations of adenosine triphosphate (ATP) in the tumor microenvironment generate adenosine by sequential dephosphorylation of CD39 and CD73, resulting in potent immunosuppression to inhibit T cell and natural killer (NK) cell function. CD73, as the determining enzyme for adenosine production, has been shown to correlate with poor clinical tumor prognosis. Conventional inhibitors as analogues of adenosine 5'-monophosphate (AMP) may have a risk of further metabolism to adenosine analogues. Here, we report a new series of malonic acid non-nucleoside inhibitors coordinating with zinc ions of CD73. Compound 12f was found to be a superior CD73 inhibitor (IC50 = 60 nM) by structural optimization, and its pharmacokinetic properties were investigated. In mouse tumor models, compound 12f showed excellent efficacy and reversal of immunosuppression in combination with chemotherapeutic agents or checkpoint inhibitors, suggesting that it deserves further development as a novel CD73 inhibitor.

Design, synthesis, and biological evaluation of diphenyl ether substituted quinazolin-4-amine derivatives as potent EGFRL858R/T790M/C797S inhibitors.

Epidermal growth factor receptor (EGFR) is a validated target for non-small-cell lung cancer (NSCLC). However, the treatment for EGFR-C797S mutation induced by third-generation EGFR inhibitors remains a concern. Therefore, the development of the fourth-generation EGFR inhibitors to overcome the EGFR-C797S mutation has great potential for clinical treatment. In this article, we designed and synthesized a series of diphenyl ether substituted quinazolin-4-amine derivatives that simultaneously occupy the ATP binding pocket and the allosteric site of EGFR. Among the newly synthesized compounds, 9d displayed excellent kinase activity against EGFRL858R/T790M/C797S with an IC50 value of 0.005 µM, and exhibited anti-proliferation activity in BaF3-EGFRL858R/T790M/C797S cells with the IC50 value of 0.865 µM. Furthermore, 9d could suppress phosphorylation of EGFR and induce cell apoptosis and cycle arrest at G2 phase in a dose-dependent manner in BaF3-EGFRL858R/T790M/C797S cells. More importantly, 9d displayed significant antitumor effects in BaF3-EGFRL858R/T790M/C797S xenograft mouse model (30 mg/kg, TGI = 71.14 %). All the results indicated compound 9d might be a novel fourth-generation EGFR inhibitor for further development in overcoming the EGFR-C797S resistance mutation.