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Photopharmacology is an emerging approach for achieving light-controlled drug activity. Herein, we design and synthesize a novel series of photoswitchable PI3K inhibitors by replacing a sulfonamide moiety with an azo group in a 4-methylquinazoline-based scaffold. Through structure-activity relationship studies, compound 6g is identified to be effectively switched between its trans - and cis -configuration under irradiation with proper wavelengths. Molecular docking studies show the cis -isomer of 6g is favorable to bind to the PI3K target, supporting compound 6g in the PSS 365 ( cis -isomer enriched) was more potent than that in the PSS dark ( trans -isomer dominated) in PI3K enzymatic assay, cell antiproliferative assay, Western blotting analysis on PI3K downstream effectors, cell cycle analysis, colony formation assay, and wound-healing assay. Relative to the cis -isomer, the trans -isomer is more metabolically stable and shows good pharmacokinetic properties in mice. Moreover, compound 6g inhibits tumor growth in nude mice and a zebrafish HGC-27 xenograft model.

PARP-1/2 inhibitors have become an important therapeutic strategy for the treatment of HR-deficient tumors. However, discovery of new inhibitors with an improved and distinct pharmacological file still need enormous explorations. Herein, a series of novel highly potent PARP-1/2 inhibitors bearing an N -substituted piperazinone moiety were achieved. In particular, Cpd36 was identified as a distinct PARP inhibitor, showing remarkable enzymatic activity not only toward PARP-1 (IC 50 = 0.94 nM) and PARP-2 (IC 50 = 0.87 nM) but also toward PARP-7 (IC 50 = 0.21 nM), as well as high selectivity over other PARP isoforms. Furthermore, Cpd36 was orally bioavailable and significantly repressed the tumor growth in both breast cancer and prostate cancer xenograft model. The crystal structures of Cpd36 within PARP-1 and PARP-2 together with the predicted binding mode within PARP-7 revealed its binding features and provided insightful information for further developing highly potent and selective PARP-1 and/or PARP-7 inhibitors.

Signal transducer and activator of transcription 3 (STAT3) is an attractive target for cancer therapy. However, identifying potent and selective STAT3 small-molecule inhibitors with drug-like properties remains challenging. Based on a scaffold combination strategy, compounds with a novel N -(benzimidazol-5-yl)-1,3,4-thiadiazol-2-amine scaffold were designed and their inhibition of the interleukin-6 (IL-6)/JAK/STAT3 pathway was tested in HEK-Blue IL-6 reporter cells. After optimization of lead compound 12 , compound 40 was identified as a selective STAT3 inhibitor that directly binds the SH2 domain to inhibit STAT3 phosphorylation, translocation, and downstream gene transcription. Compound 40 exhibited antiproliferative activities against STAT3-overactivated DU145 (IC 50 value = 2.97 μM) and MDA-MB-231 (IC 50 value = 3.26 μM) cancer cells and induced cell cycle arrest and apoptosis. In the DU145 xenograft model, compound 40 showed in vivo antitumor efficacy following intraperitoneal administration, with a tumor growth inhibition rate of 65.3% at 50 mg/kg, indicating promise for further development.

Osimertinib resistance is an unmet clinical need for the treatment of non-small cell lung cancer (NSCLC), and the main mechanism is tertiary C797S mutation of epidermal growth factor receptor (EGFR). To date, there is no inhibitor approved for the treatment of Osimertinib-resistant NSCLC. Herein, we reported a series of Osimertinib derivatives as fourth-generation inhibitors which were rationally designed. Top candidate D51 potently inhibited the EGFR L858R/T790M/C797S mutant with an IC 50 value of 14 nM and suppressed the proliferation of H1975-TM cells with an IC 50 value of 14 nM, which show over 500-fold selectivity against wild-type forms. Moreover, D51 inhibited the EGFR del19/T790M/C797S mutant and the proliferation of the PC9-TM cell line with IC 50 values of 62 and 82 nM. D51 also exhibited favorable in vivo druggability, including PK parameters, safety properties, in vivo stability, and antitumor activity.

Prostate cancer (PCa) is a common male cancer with high incidence and mortality, and hormonal therapy as the major treatment for PCa patients is troubled by the inevitable resistance that makes us identify novel targets for PCa. Dual-specificity tyrosine phosphorylation-regulated kinase 2 (DYRK2) was found to be an effective target for the treatment of PCa, but the research on its inhibitors is rather little. In this work, a potent DYRK2 inhibitor 43 (IC 50 = 0.6 nM) was acquired through virtual screening and structural optimization, which displayed high selectivity among 205 kinases; meanwhile, detailed interactions of 43 with DYRK2 were illustrated by the cocrystal. Furthermore, 43 possessed great water solubility (29.5 mg/mL), favorable safety properties (LD 50 > 10,000 mg/kg), and potent anti-PCa activities, which could be used as a potential candidate in further preclinical studies.

High levels of steady-state mitochondrial reactive oxygen species (ROS) and glycolysis are hallmarks of cancer. An improved understanding of interactions between tumor energetics and mitochondrial ROS modulation is useful for the development of new anticancer strategies. Here, we show that the natural product chlorogenic acid ( CGA ) specifically scavenged abnormally elevated mitochondrial O 2 •- and exhibited a two-photon fluorescence turn-on response to tumor cells under hypoxia and tumor tissues in vivo . Furthermore, we illustrated that CGA treatment reduced O 2 •- levels in cells, hampered activation of AMP-activated protein kinase (AMPK), and shifted metabolism from glycolysis to oxidative phosphorylation (OXPHOS), resulting in inhibition of tumor growth under hypoxia. This study demonstrates an efficient two-photon fluorescent tool for real-time assessment of mitochondrial O 2 •- and a clear link between reducing intracellular ROS levels by CGA treatments and regulating metabolism, as well as undeniably helpful insights for the development of new anticancer strategies.

Targeting the colchicine binding site on tubulin is a promising strategy to develop cancer therapeutics. Herein, we describe our systematic structure-activity relationship studies of benzamide derivatives that lead to an identification of a potent and orally active tubulin inhibitor 48 , which occupied all three zones of the colchicine binding site in the X-ray co-crystal structure, inhibited tubulin polymerization, promoted mitotic blockade and apoptosis, and exhibited significant antiproliferative activities against various cancer cell lines. Compound 48 demonstrated favorable pharmacokinetic profiles, robust in vivo antitumor efficacies, and acceptable safety profiles. Furthermore, 48 overcame drug resistance in the paclitaxel-resistant A549 xenograft model. Collectively, 48 has been advanced into further preclinical evaluation for the development of next-generation microtubule-targeting drugs.

Breast cancer is the most common tumor in women, and selective cyclin-dependent kinase (CDK) 4/6 inhibitors played an important role in the treatment of breast cancer. Therefore, discovering selective CDK4/6 inhibitors with great safety and potent efficacy is beneficial for the breast cancer treatment. In our work, the lead compound 8 was identified through virtual screening; then, systematic structural optimization was conducted to afford 42 , which exhibited strong inhibition on CDK4/6 and showed high selectivity among 205 kinases. 42 possessed excellent safety profiles (LD 50 > 5,000 mg/kg), favorable pharmacokinetic properties ( F % = 43%), and potent efficacy in reducing the burden of breast cancer in vivo. In conclusion, we offered a highly selective CDK4/6 inhibitor, which could be used as a great candidate for further preclinical studies of breast cancer.

Nowadays, the simultaneous inhibition of two or more pathways plays an increasingly important role in cancer treatment due to the complex and diverse pathogenesis of cancer, and the combination of the cyclin-dependent kinase 6 (CDK6) inhibitor and PIM1 inhibitor was found to generate synergistic effects in acute myeloid leukemia (AML) treatment. Therefore, we discovered a novel lead 1 targeting CDK6/PIM1 via pharmacophore-based and structure-based virtual screening, synthesized five different series of new derivates, and obtained a potent and balanced dual CDK6/PIM1 inhibitor 51 , which showed high kinase selectivity. Meanwhile, 51 displayed an excellent safety profile and great pharmacokinetic properties. Furthermore, 51 displayed stronger potency in reducing the burden of AML than palbociclib and SMI-4a in vivo . In summary, we offered a new direction for AML treatment and provided a great lead compound for AML preclinical studies.

Increasing evidence shows that the CXC chemokine receptor 2 (CXCR2) signaling pathway is essentially implicated in the recruitment of myeloid-derived suppressor cells (MDSCs) to the tumor microenvironment and leads to MDSC-mediated immune suppression. Therefore, CXCR2 has recently emerged as a promising drug target for cancer immunotherapy. In this paper, benzocyclic sulfone derivatives were designed as potent CXCR2 antagonists. Structure-activity relationship studies resulted in two lead compounds 9b and 11h , which demonstrated double-digit nanomolar potencies against CXCR2 and significantly inhibited neutrophil infiltration into the air pouch in an in vivo setting. More importantly, 9b and 11h dose-dependently inhibited the tumor growth through oral administration in the Pan02 mouse model. Further cytometry and immunohistochemical analyses revealed that 9b and 11h could reduce the infiltration of neutrophils and MDSCs and enhance the infiltration of CD3 + T lymphocytes into the Pan02 tumor tissues, shedding light on their mechanisms of action in cancer immunotherapy.

Inhibiting PARP-1/2 offered an important arsenal for cancer treatments via interfering with DNA repair of cancer cells. Novel PARP-1/2 inhibitors were designed by capitalizing on methyl- or ethyl-substituted piperizine ring to capture the characteristics of adenine-ribose binding site (AD site), and their unique binding features were revealed by the cocrystal structures of compounds 4 and 6 in PARP-1. The investigation on structure-activity relationship resulted in compounds 24 and 32 with high enzymatic potency, binding selectivity, and significantly longer residence time for PARP-1 over PARP-2 (compound 24 , PARP-1: IC 50 = 0.51 nM, PARP-2: IC 50 = 23.11 nM; compound 32 , PARP-1: IC 50 = 1.31 nM, PARP-2: IC 50 = 15.63 nM). Furthermore, compound 24 was determined to be an attractive candidate molecule, which possessed an acceptable pharmacokinetic profile and produced remarkable antitumor activity in both breast cancer xenograft model and glioblastoma orthotopic model in mice, either alone or in combination treatment.

Aberrant activation of the PI3K pathway has been intensively targeted for cancer therapeutics for decades, leading to more than 40 PI3K inhibitors advanced into clinical trials. However, it is increasingly noticed that PI3K inhibitors often showed limited efficacy as well as a number of serious on-target adverse effects during the clinical development. In this work, we designed and synthesized a novel photocaged PI3K inhibitor 1 , which could be readily activated by UV irradiation to release a highly potent PI3K inhibitor 2 . Upon UV irradiation, the photocaged inhibitor 1 demonstrated remarkably enhanced antiproliferative activity against multiple cancer cell lines and significant efficacy in the patient-derived tumor organoid model. Furthermore, 1 also showed favorable anticancer activity in an in vivo zebrafish xenograft model. Taken together, the photocaged PI3K inhibitor 1 represents a promising avenue for novel therapeutics toward precise cancer treatment.

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease, and its molecular pathogenesis remains poorly understood. Recently, emerging evidence demonstrates that the PI3K signaling transduction pathway is linked to the pathology of IPF. In this work, we rationally designed a new series of 4-methylquinazoline derivatives as highly potent PI3K inhibitors that significantly suppress the phosphorylation of the main PI3K downstream effectors and displays marked antiproliferative activity in mouse MLg2908 lung fibroblasts. In a bleomycin-induced mouse pulmonary fibrosis model, 5d from the series improved mouse lung function and slowed the progression of pulmonary fibrosis. Overall, this work promises a therapeutic potential for PI3K inhibitors to treat IPF.

Recent efforts to identify new highly potent arginase inhibitors have resulted in the discovery of a novel family of (3 R ,4 S )-3-amino-4-(3-boronopropyl)pyrrolidine-3-carboxylic acid analogues with up to a 1000-fold increase in potency relative to the current standards, 2-amino-6-boronohexanoic acid (ABH) and N -hydroxy-nor-l-arginine (nor-NOHA). The lead candidate, with an N -2-amino-3-phenylpropyl substituent (NED-3238), example 43 , inhibits arginase I and II with IC 50 values of 1.3 and 8.1 nM, respectively. Herein, we report the design, synthesis, and structure-activity relationships for this novel series of inhibitors, along with X-ray crystallographic data for selected examples bound to human arginase II.

Polypharmacology is a promising paradigm in modern drug discovery. Herein, we have discovered a series of novel PI3K and HDAC dual inhibitors in which the hydroxamic acid moiety as the zinc binding functional group was introduced to a quinazoline-based PI3K pharmacophore through an appropriate linker. Systematic structure-activity relationship studies resulted in lead compounds 23 and 36 that simultaneously inhibited PI3K and HDAC with nanomolar potencies and demonstrated favorable antiproliferative activities. Compounds 23 and 36 efficiently modulated the expression of p-AKT and Ac-H3, arrested the cell cycle, and induced apoptosis in HCT116 cancer cells. Following pharmacokinetic studies, 23 was further evaluated in HCT116 and HGC-27 xenograft models to show significant in vivo anticancer efficacies with tumor growth inhibitions of 45.8% (po, 150 mg/kg) and 62.6% (ip, 30 mg/kg), respectively. Overall, this work shows promise in discovering new anticancer therapeutics by the approach of simultaneously targeting PI3K and HDAC pathways with a single molecule.

Cyclophilins are a family of peptidyl-prolyl isomerases that are implicated in a wide range of diseases including hepatitis C. Our aim was to discover through total synthesis an orally bioavailable, non-immunosuppressive cyclophilin (Cyp) inhibitor with potent anti-hepatitis C virus (HCV) activity that could serve as part of an all oral antiviral combination therapy. An initial lead 2 derived from the sanglifehrin A macrocycle was optimized using structure based design to produce a potent and orally bioavailable inhibitor 3. The macrocycle ring size was reduced by one atom, and an internal hydrogen bond drove improved permeability and drug-like properties. 3 demonstrates potent Cyp inhibition ( K d = 5 nM), potent anti-HCV 2a activity (EC 50 = 98 nM), and high oral bioavailability in rat (100%) and dog (55%). The synthetic accessibility and properties of 3 support its potential as an anti-HCV agent and for interrogating the role of Cyp inhibition in a variety of diseases.

Increased phosphatidylinositol 3-kinase (PI3K) signaling is among the most common alterations in cancer, spurring intensive efforts to develop new cancer therapeutics that target this pathway. In this work, we discovered a series of novel 2-amino-4-methylquinazoline derivatives through a hybridization and subsequent scaffold hopping approach that were highly potent class I PI3K inhibitors. Lead optimization resulted in several promising compounds (e.g., 19, 20, 37, and 43) with nanomolar PI3K potencies, prominent antiproliferative activities, favorable PK profiles, and robust in vivo antitumor efficacies. More interestingly, compared with 19 and 20, 37 and 43 demonstrated improved brain penetration and in vivo efficacy in an orthotopic glioblastoma xenograft model. Furthermore, preliminary safety assessments including hERG channel inhibition, AMES, CYP450 inhibition, and single-dose toxicity were performed to characterize their toxicological properties.

The exploration of novel inhibitors of the HCV NS4B protein that are based on a 2-oxadiazoloquinoline scaffold is described. Optimization to incorporate activity across genotypes led to a potent new series with broad activity, of which inhibitor 1 displayed the following EC50 values: 1a, 0.08 nM; 1b, 0.10 nM; 2a, 3 nM; 2b, 0.6 nM, 3a, 3.7 nM; 4a, 0.9 nM; 6a, 3.1 nM.