Structural optimizations on the 7H-pyrrolo[2,3-d]pyrimidine scaffold to develop highly selective, safe and potent JAK3 inhibitors for the treatment of Rheumatoid arthritis.

Janus Kinase 3 (JAK3) is important for the signaling transduction of cytokines in immune cells and is identified as potential target for treatment of rheumatoid arthritis (RA). Recently, we designed and synthesized two JAK3 inhibitors J1b and J1f, which featured with high selectivity but mild bioactivity. Therefore, in present study the structure was optimized to increase the potency. As shown in the results, most of the compounds synthesized showed stronger inhibitory activities against JAK3 in contrast to the lead compounds, among which 9a was the most promising candidate because it had the most potent effect in ameliorating carrageenan-induced inflammation of mice and exhibited low acute in vivo toxicity (MTD > 2 g/kg). Further analysis revealed that 9a was highly selective to JAK3 (IC50 = 0.29 nM) with only minimal effect on other JAK members (>3300-fold) and those kinases bearing a thiol in a position analogous to that of Cys909 in JAK3 (>150-fold). Meanwhile, the selectivity of JAK3 was also confirmed by PBMC stimulation assay, in which 9a irreversibly bound to JAK3 and robustly inhibited the signaling transduction with mild suppression on other JAKs. Moreover, it was showed that 9a could remarkably inhibited the proliferation of lymphocytes in response to concanavalin A and significantly mitigate disease severity in collagen induced arthritis. Therefore, present data indicate that compound 9a is a selective JAK3 inhibitor and could be a promising candidate for clinical treatment of RA.

Development of novel nitric oxide production inhibitors based on the 7H-pyrrolo[2,3-d]pyrimidine scaffold.

Nitric oxide (NO), the smallest signaling molecule known, can be excessively produced by overexpressed inducible nitric oxide synthase (iNOS), and eventually leads to multiple inflammatory related diseases. Thus, reducing the overexpression of NO represents as very potential anti-inflammatory strategy. In current study, a series of compounds were designed and synthesized based on the hybridization of 7H-pyrrolo[2,3-d]pyrimidine and cinnamamide fragments in order to develop novel NO production inhibitors. Among them, compound S2h displayed a vigorous inhibitory activity on NO production with an IC50 value of 3.21 ± 0.67 µM, which was much lower than that of the positive control Nω-nitro-L-arginine (L-NNA, IC50 = 28.36 ± 3.13 µM). Due to its obeying Lipinski's and Veber's rules that guarantee compounds with good oral bioavailability, S2h effectively suppressed the paw swelling in carrageenan-induced mice. Additionally, compound S2h formed clear interactions with iNOS protein according to the docking analysis. Therefore, compounds S2h is a promising lead compound for further development of potent iNOS inhibitors or anti-inflammatory agents.

Design and synthesis of highly selective Janus kinase 3 covalent inhibitors for the treatment of rheumatoid arthritis.

Selective inhibition of Janus kinase 3 (JAK3) is a promising strategy for the treatment of autoimmune diseases. Based on the discovery of a hydrophobic pocket unutilized between the lead compound RB1 and the JAK3 protein, a series of covalent JAK3 inhibitors were prepared by introducing various aromatic fragments to RB1. Among them, J1b (JAK3 IC50 = 7.2 nM, other JAKs IC50 > 1000 nM) stood out because of its low toxicity (MTD > 2 g/kg) and superior anti-inflammatory activity in Institute of Cancer Research mice. Moreover, the acceptable bioavailability (F% = 31.69%) ensured that J1b displayed excellent immune regulation in collagen-induced arthritis mice, whose joints in the high-dose group were almost recovered to a normal state. Given its clear kinase selectivity (Bmx IC50 = 539.9 nM, other Cys909 kinases IC50 > 1000 nM), J1b was nominated as a highly selective JAK3 covalent inhibitor, which could be used to safely treat arthritis and other autoimmune diseases.

Detection of the freshness of rice by chemiluminescence.

Reactive oxygen species (ROS) are usually produced in rice under aerobic environmental conditions, resulting in peroxidative changes in polyunsaturated fatty acids, and affecting the deterioration of rice during storage. In addition, as an important enzyme that participates in removing ROS, peroxidase is also present in rice, and takes part in protecting rice from attack by ROS. Moreover, loss of peroxidase activity may give rise to rice deterioration during storage. Therefore, measuring peroxidase activity makes it possible to ascertain the freshness of rice. In addition, peroxidase can also catalyze the luminol-hydrogen peroxide system. Based on this, in this work we established a new chemiluminescence (CL) method that was used to detect the freshness of stored rice. Under optimal experimental conditions, we showed that the freshness of rice can be measured using this CL method. This study is the first to detect the freshness of rice using a CL method, opening up a novel direction for the application of CL.

Engineering highly efficient Li+ responsive nanochannels via host-guest interaction and photochemistry regulation.

Artificial nanochannels have seen great progress in energy storage, molecular filters, nanofluidic diodes, and biosensors. Precisely recognizing and transporting molecules or ions underpin the basis of artificial nanochannels. Here, we report highly efficient Li+ responsive nanochannels by design of functionalized porous anodic aluminum oxide (AAO) membranes. The 12-crown-4 unit was tethered to the synthesized spiropyran molecule, creating a smart Li+ responsive element, photochromic crowned spiropyran (CE-SP). The crown unit can specifically bind with Li+ while exempting the harassment of other metallic cations; and importantly, the spiropyran moiety possesses reversible photochemistry response, adding the flexibility to regulate ion transport behaviors. Upon the ultraviolet light stimulus, hydrophobic CE-SP molecules transform to positively charged crowned merocyanine (CE-MC), which can further convert to oxygen-negative ions in weak alkaline environment, thereby forming O--Li+ interaction. Such structural evolutions enable to deftly tune the surface charge and wettability of the nanochannels, and thus ingeniously manipulate Li+ recognition profiled by ionic current signal. Moreover, electrically-driven release of the captured Li+ can be realized in an amiable condition, showing controllable capture-to-release ability. Finite element simulation unveils the fundamental mechanisms of ion transport pertaining to Li+ recognition events in the nanoconfinement. This work thus paves a way to construct high-performance Li+-selective nanodevice, and holds promise for Li+-related electrochemistry energy research.

Optimization of the benzamide fragment targeting the S2' site leads to potent dipeptidyl peptidase-IV inhibitors.

Our recently successful identification of benzoic acid-based DPP-4 inhibitors spurs the further quest for in-depth structure-activity relationships (SAR) study in S2' site DPP-4. Thus novel benzamide fragments were designed to target the S2' site to compromise lipophilicity and improve oral activity. Exploring SAR by introduction of a variety of amide and halogen on benzene ring led to identification of several compounds, exerting moderated to excellent DPP-4 activities, in which 4'-chlorine substituted methyl amide 17g showed most potent DPP-4 activity with the IC50 value of 1.6 nM. Its activity was superior to reference alogliptin. Docking study ideally verified and interpreted the obtained SAR of designed compounds. As a continuation, DPP-8/9 assays revealed the designed compounds exhibited good selectivity over DPP-8 and DPP-9. Subsequent cell-based test indicated compound 17g displayed low toxicity toward the LO2 cell line up to 100 µM. In vivo evaluation showed compound 17g robustly improved the glucose tolerance in normal mice. Importantly, 17g exhibited reasonable pharmacokinetic (PK) profiles for oral delivery. Overall, compound 17g has the potential to a safe and efficacious DPP-4 inhibitor for T2DM treatment.

Design, synthesis, and biological evaluation of quinazoline derivatives as dual HDAC1 and HDAC6 inhibitors for the treatment of cancer.

Fifty-eight quinazoline-based compounds were designed and synthesized based on the structural optimizations from the lead compound 23bb in an attempt to search for more potent dual HDAC1 and HDAC6 inhibitors. Among them, 32c (HDAC1, IC50  = 31.10 ± 0.37 nM; HDAC6, IC50  = 16.15 ± 0.62 nM) and 32d (HDAC1, IC50  = 37.00 ± 0.24 nM; HDAC6, IC50  = 35.00 ± 0.71 nM) were not only identified as potent dual-acting HDAC1 and HDAC6 inhibitors with over 10-fold selectivity to the other HDACs, but also displayed activities in tubulin acetylation and histone H3 acetylation induction. Importantly, both of them displayed strong antiproliferative activities against various tumor cell lines in vitro with IC50 values less than 40 nM, especially for hematologic tumors cells (U266 and RPMI8226, IC50  < 1 nM), which were even better than 23bb and SAHA. Furthermore, 32c showed a significant tumor growth inhibition (antitumor rate = 63.98%, p < 0.05) in the resistant MCF-7/ADR xenograft model without any obvious body weight changes and abnormal behaviors. Our findings validate that 32c is a potent dual inhibitor of HDAC1/6 that can be an efficacious treatment for breast cancer with Adriamycin resistance.

Discovery of a highly selective JAK3 inhibitor for the treatment of rheumatoid arthritis.

Janus tyrosine kinase 3 (JAK3) is expressed in lymphoid cells and is involved in the signalling of T cell functions. The development of a selective JAK3 inhibitor has been shown to have a potential benefit in the treatment of autoimmune disorders. In this article, we developed the 4-aminopiperidine-based compound RB1, which was highly selective for JAK3 inhibition, with an IC50 of value of 40 nM, but did not inhibit JAK1, JAK2 or tyrosine kinase 2 (TYK2) at concentrations up to 5 µM. Furthermore, RB1 also exhibited favourable selectivity against a panel of representative kinases. In a battery of cytokine-stimulated cell-based assays, this potent inhibitor of JAK3 activity with good selectivity against other kinases could potently inhibit JAK3 activity over the activity of JAK1 or JAK2 (over at least 100-fold). A combination of liquid chromatography-mass spectrometry (LC-MS) experiments validated that RB1 covalently modified the unique cysteine 909 residue in JAK3. In vivo, RB1 exerted significantly improved pathology in the joints of a collagen-induced arthritis mouse model. The reasonable pharmacokinetics properties (F = 72.52%, T1/2 = 14.6 h) and favourable results of toxicology experiments (LD50 > 2 g/kg) suggest that RB1 has the potential to be an efficacious treatment for RA.

Design, synthesis, and SAR study of highly potent, selective, irreversible covalent JAK3 inhibitors.

Here, we report the design and synthesis of pyrimidinyl heterocyclic compounds containing terminal electrophiles as irreversible covalent JAK3 inhibitors that exploit a unique cysteine (Cys909) residue in JAK3. Investigation of the structure-activity relationship utilizing kinase assays resulted in the identification of potent and selective JAK3 inhibitors such as T1, T8, T15, T22, and T29. Among them, T29 was verified as a promising JAK3 irreversible inhibitor that possessed the best bioactivity and selectivity against JAKs and kinases containing a cysteine in the residue analogous to Cys909 in JAK3, suggesting that covalent modification of this Cys residue allowed the identification of a highly selective JAK3 inhibitor. Moreover, T29 also displayed a significant anti-inflammatory effect in ICR mice through the inhibition of increased paw thickness, which is worth further optimization to increase its potency and medicinal properties.

Design, synthesis and biological evaluation of 7H-pyrrolo[2,3-d]pyrimidin-4-amine derivatives as selective Btk inhibitors with improved pharmacokinetic properties for the treatment of rheumatoid arthritis.

Bruton's tyrosine kinase (Btk) is a Tec family kinase with a well-defined role in the B cell receptor (BCR) and Fcγ receptor (FcR) signaling pathways, which makes it a uniquely attractive target for the treatment of autoimmune diseases, such as rheumatoid arthritis (RA). We reported a series of compounds bearing 7H-pyrrolo [2,3-d]pyrimidin-4-amine scaffold that potently inhibited Btk in vitro. Analysis of the structure-activity relationships (SAR) and drug-like profiles led to the discovery of the optimal compound B16. B16 preferentially inhibited Btk (IC50 = 21.70 ±â€¯0.82 nM) over closely related kinases with moderate selectivity. Cell-based tests also confirmed that B16 significantly inhibited Btk Y223 auto-phosphorylation and PLCγ2 Y1217 phosphorylation. MTT revealed that B16 displayed weak suppression against normal LO2, HEK293 and THP-1 cell lines with IC50 values over 30 µM. Moreover, B16 showed very weak potential to block the hERG channel (IC50 = 11.10 µM) in comparison to ibrutinib (IC50 = 0.97 µM). Owing to its favorable physicochemical properties (ClogP = 2.53, aqueous solubility ≈ 0.1 mg/mL), pharmacokinetic profiles (F = 49.15%, t1/2 = 7.02 h) and reasonable CYP450 profile, B16 exhibited potent anti-arthritis activity and similar efficacy to ibrutinib in reducing paw thickness in CIA mice. In conclusion, B16 is a potent, selective and durable inhibitor of Btk and has the potential to a safe and efficacious treatment for arthritis.

Design and Synthesis of a Highly Selective JAK3 Inhibitor for the Treatment of Rheumatoid Arthritis.

Selective inhibition of Janus kinase 3 (JAK3) has been identified as an important strategy for the treatment of autoimmune disorders. Based on the unique cysteine 909 residue (Cys909) of JAK3 at the gatekeeper position, we have developed a new irreversible covalent inhibitor, III-4, which is highly potent and selective in targeting JAK3. Importantly, III-4 selectively inhibited JAK3 (IC50 = 57 ± 1.21 nM) over other JAKs (IC50 > 10 µM) and Cys909 kinome members (IC50 > 1 µM). A cellular selectivity study also confirmed that III-4 preferentially inhibited JAK3 over JAK1 in JAK/STAT signaling. Moreover, the fact that III-4 covalently modified the Cys909 residue in JAK3 was clearly validated by mass spectrometry and covalent docking analysis. Based on the favorable target profiles, the pharmacokinetic properties and its low toxicity, III-4 exhibited better efficacy than tofacitinib in impeding disease progression in CIA mice, without any significant adverse effects. Taken together, III-4 is a potent, selective, and durable inhibitor of JAK3 and has the potential for the treatment of inflammatory disorders and autoimmune diseases, such as rheumatoid arthritis.

Structure-based design, synthesis and in vitro antiproliferative effects studies of novel dual BRD4/HDAC inhibitors.

Histone acetylation marks play important roles in controlling gene expressions and are removed by histone deacetylases (HDACs). These marks are read by bromodomain and extra-terminal (BET) proteins, whose targeted inhibitors are under clinical investigation. BET and HDAC inhibitors have been demonstrated to be synergistically killing in Mycinduced murine lymphoma. Herein, we combine the inhibitory activities of BET and HDAC into one molecule through structure-based design method and evaluate its function. The majority of these synthesized compounds showed inhibitory activity against second bromdomains(BRD) of BRD4 and HDAC1. Among them, 16ae presented anti-proliferative effects against human acute myelogenous leukemia (AML) cell lines in vitro, and 16ae is confirmed to reduce the expression of Myc by Western blot analysis. Those results indicated that 16ae is a potent dual BRD4/HDAC inhibitor and deserves further investigation.

Design, synthesis and biological evaluation of 4-anilinoquinoline derivatives as novel potent tubulin depolymerization agents.

A series of novel 4-anilinoquinoline derivatives were synthesized and evaluated for their antiproliferative activities. Among them, 14h exhibited the most potent cytotoxic activity with IC50 values ranging from 1.5 to 3.9 nM against all tested cancer cell lines, and showed promising efficacy in multidrug resistant cancer cells. Flow cytometry assay, immune-fluorescence staining, microtubule dynamics assays and competition assays with EBI identified that 14h was a novel tubulin depolymerization agent by binding to the colchicine site. Importantly, in vivo efficacy evaluation of HCT116 xenograft model, 14h showed efficient antitumor activity without significant loss in body weight. All the results indicated that 14h could be a promising candidate for the treatment of cancer.

Discovery of (R)-5-(benzo[d][1,3]dioxol-5-yl)-7-((1-(vinylsulfonyl)pyrrolidin-2-yl)methyl)-7H-pyrrolo[2,3-d]pyrimidin-4-amine (B6) as a potent Bmx inhibitor for the treatment of NSCLC.

Described as a Btk inhibitor, ibrutinib also potently inhibits Bmx and EGFR, two good targets for lung cancer. Owing to its high CLogP (4.07) and low aqueous solubility (<0.01mg/ml), resulting in unfavorable bioavailability, ibrutinib requires high dosages to achieve good clinical response in the treatment of non-small cell lung cancer (NSCLC). In our effort to improve the CLogP of ibrutinib by structural optimization led to the discovery of a potent anti-cancer agent B6, with beneficial physicochemical parameters (CLogP=2.56, solubility in water≈0.1mg/ml) meeting the principles of oral drugs. B6 exhibited anti-proliferation activities against EGFR-expressing cells, especially the mutant ones, such as H1975 (L858R/T790M, IC50=0.92±0.19µM) and HCC827 (Del119 IC50=0.014±0.01µM). Moreover, B6 significantly slowed down H1975 tumor growth with anti-tumor rate of 73.9% (p<0.01). Enzyme potencies assay demonstrated B6 moderately selectively inhibited Bmx (IC50=35.7±0.1nM) over other kinases. So, as a potent Bmx inhibitor, B6 has the potential to be an efficacious treatment for NSCLC with acquired drug resistance.

Discovery of 5-methyl-2-(4-((4-(methylsulfonyl)benzyl)oxy)phenyl)-4-(piperazin-1-yl)pyrimidine derivatives as novel GRP119 agonists for the treatment of diabetes and obesity.

A series of fused-pyrimidine derivatives were prepared and evaluated for their agonistic activities against human GPR119. Compound 9i showed high potent agonistic activity against HEK293T cells over-expressing human GPR119 and improved glucose tolerance in dose-dependent manner, as well as promoted insulin secretion. In a DIO mice model, 9i also ameliorated the obese-related symptoms by decreasing the body weights without markedly changing food intake, normalized some serum biomarkers, such as ALT, AST, ALP, GLU, CHOL, HDL, and LDL, and exerted therapeutic activity on fat deposition in liver tissue. We consider 9i to have utility as a GPR119 agonists for the treatment of type 2 diabetes mellitus and obese-related symptoms.

Discovery of novel CDK8 inhibitors using multiple crystal structures in docking-based virtual screening.

The cyclin dependent kinase CDK8, along with Med12 and Med13, form the kinase module of the Mediator complex. CDK8 expression associates with the activation of ß-catenin in colon and gastric cancers. Herein, we applied docking-based virtual screening (VS) using the multiple crystal structures to identify several potent CDK8 inhibitors. The appropriate use of multiple crystal structures obtained a better enrichment of CDK8 conformations to cope with the protein flexibility. Later on, the 2D similarity search was used to find the derivatives of the high inhibitory CDK8 inhibitors we discovered by VS. Finally, we measured the dose response behaviors, the IC50 values of compound W-34, W-37, W-8, WS-2 are 6.5 nM, 36 nM, 93 nM, 9 nM, respectively. These novel leads provided good starting points to design and synthesis a series of highly selective and potent CDK8 inhibitors.

Synthesis and biological evaluation of novel pyrazoline derivatives as potent anti-inflammatory agents.

Twenty-eight pyrazoline derivatives, which originated from pyranochalcones, have been synthesized and evaluated for their inhibitory potency on the production of inflammatory mediator nitric oxide (NO) in LPS-stimulated RAW 264.7 cells. Among them, three compounds (1c, 11c, and 15c) exhibited potent inhibitory effects on NO production and iNOS activity superior to positive control Indomethacin, with 1c being most efficacious. Furthermore, 1c could suppress the progress of carrageenan-induced hind paw edema at a dosage of 50 mg/kg/day and dose-dependently ameliorate the development of adjuvant-induced arthritis (AIA). Docking study confirmed that 1c was an iNOS inhibitor with good binding into the active site of murine iNOS.

Structural exploration, synthesis and pharmacological evaluation of novel 5-benzylidenethiazolidine-2,4-dione derivatives as iNOS inhibitors against inflammatory diseases.

In our previous work, 3I inhibited the LPS-induced iNOS activity and NO production in RAW 264.7 cells and improved joint inflammation and cartilage destruction in inflammatory model. In this study, we synthesized 59 derivatives and bioisosteres on the basis of 3I by Knoevenagel condensation and biologically evaluated for the study of structure-activity relationship (SAR). We found that 7-44 suppressed the iNOS activity (IC50 25.2 µM) and LPS-induced NO production (IC50 45.6 µM) in RAW 264.7 cells. As for the SAR study, the dimethoxylphenyl group of 7-44 was potential for a further modification. At a dose of 10 mg/kg, oral administration of 7-44 possessed protective properties in both carrageenan-induced paw edema of male ICR mice and adjuvant-induced arthritis of Lewis female rats. Although the activity of 7-44 was slightly inferior, the PK profiles of 7-44 were superior to those of 3I.

Discovery of a Potent 9-Deazaxanthine-based Agent for the Treatment of Obesity-Related Non-alcoholic Fatty Liver Disease.

A series of deazaxanthine-based derivatives were rationally prepared and evaluated. 8g exhibited the most potent glucose-lowering effect on HepG2 cell line and modulated adiponectin and leptin expression in 3T3-L1 adipocytes. Oral administration of 8g at 25 mg/kg/day for 4 weeks manifested therapeutic effects on high-fat diet-induced non-alcoholic fatty liver disease (NAFLD) by decreasing the weights of the body, liver, and fat. 8g also modulated the serum levels of fasting glucose and adiponectin, triglycerides, low-density lipoprotein-cholesterol, and alanine aminotransferase, as well as the hepatic concentrations of triglycerides, total cholesterol. Moreover, 8g significantly decreased steatosis and blocked the increase of adipocytes and the size of adipose tissues from NAFLD. In the DIO mice model, 8g ameliorated the obesity-related symptoms and normalized serum biomarkers.