Structure-based design and synthesis of BML284 derivatives: A novel class of colchicine-site noncovalent tubulin degradation agents.

Our previous studies have demonstrated that BML284 is a colchicine-site tubulin degradation agent. To improve its antiproliferative properties, 45 derivatives or analogs of BML284 were designed and synthesized based on the cocrystal structure of BML284 and tubulin. Among them, 5i was the most potent derivative, with IC50 values ranging from 0.02 to 0.05 µM against the five tested tumor cell lines. Structure-activity relationship studies verified that the N1 atom of the pyrimidine ring was the key functional group for its tubulin degradation ability. The 5i-tubulin cocrystal complex revealed that the binding pattern of 5i to tubulin is similar to that of BML284. However, replacing the benzodioxole ring with an indole ring strengthened the hydrogen bond formed by the 2-amino group with E198, which improved the antiproliferative activity of 5i. Compound 5i effectively suppressed tumor growth at an intravenous dose of 40 mg/kg (every 2 days) in paclitaxel sensitive A2780S and paclitaxel resistant A2780T ovarian xenograft models, with tumor growth inhibition values of 79.4% and 82.0%, respectively, without apparent side effects, showing its potential to overcome multidrug resistance. This study provided a successful example of crystal structure-guided discovery of 5i as a colchicine-targeted tubulin degradation agent, expanding the scope of targeted protein degradation.

Fragment growth-based discovery of novel TNIK inhibitors for the treatment of colorectal cancer.

Traf2-and Nck-interacting protein kinase (TNIK) plays an important role in regulating signal transduction of the Wnt/ß-catenin pathway and is considered an important target for the treatment of colorectal cancer. Inhibiting TNIK has potential to block abnormal Wnt/ß-catenin signal transduction caused by colorectal cancer mutations. We discovered a series of 6-(1-methyl-1H-imidazole-5-yl) quinoline derivatives as TNIK inhibitors through Deep Fragment Growth and virtual screening. Among them, 35b exhibited excellent TNIK kinase and HCT116 cell inhibitory activity with IC50 values of 6 nM and 2.11 µM, respectively. 35b also shown excellent kinase selectivity, PK profiles, and oral bioavailability (84.64%). At a p. o. dosage of 50 mg/kg twice daily 35b suppressed tumor growth on the HCT116 xenograft model. Taken together, 35b is a promising lead compound of TNIK inhibitors, which merits further investigation.

Discovery of 4-amino-1,6-dihydro-7H-pyrrolo[2,3-d]pyridazin-7-one derivatives as potential receptor-interacting serine/threonine-protein kinase 1 (RIPK1) inhibitors.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is an important regulatory factor in the necroptosis signaling pathway, and is considered an attractive therapeutic target for treating multiple inflammatory diseases. Herein, we describe the design, synthesis, and structure-activity relationships of 4-amino-1,6-dihydro-7H-pyrrolo [2,3-d]pyridazin-7-one derivatives as RIPK1 inhibitors. Among them, 13c showed favorable RIPK1 kinase inhibition activity with an IC50 value of 59.8 nM, and high RIPK1 binding affinity compared with other regulatory kinases of necroptosis (RIPK1 Kd = 3.5 nM, RIPK3 Kd = 1700 nM, and MLKL Kd > 30,000 nM). 13c efficiently blocked TNFα-induced necroptosis in both human and murine cells (EC50 = 1.06-4.58 nM), and inhibited TSZ-induced phosphorylation of the RIPK1/RIPK3/MLKL pathway. In liver microsomal assay studies, the clearance rate and half-life of 13c were 18.40 mL/min/g and 75.33 min, respectively. 13c displayed acceptable pharmacokinetic characteristics, with oral bioavailability of 59.55%. In TNFα-induced systemic inflammatory response syndrome, pretreatment with 13c could effectively protect mice from loss of body temperature and death. Overall, these compounds are promising candidates for future optimization studies.

Therapeutic potential of a synthetic dual JAK1/TYK2 inhibitor in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic and incurable disease with an increasing incidence rate and low mortality rate. Selectively inhibiting JAK1 and TYK2 has been proposed as a strategy to enhance the efficacy of such inhibitors while minimizing the potential side effects on other JAK isoforms. Our previous studies identified small molecule 18 as a JAK1/TYK2 inhibitor with high selectivity and a new structure. Specifically, the IC50 of 18 at the kinase level reached 39 nM and 21 nM for JAK1 and TYK2, respectively, with 10-fold selectivity over both JAK2 and JAK3. In in vitro studies, 18 dose-dependently inhibited cytokine-induced STAT phosphorylation downstream of the JAK1 and TYK2 signaling pathway. In pharmacokinetic experiments, 18 demonstrated an oral bioavailability of 59.82%, making it a promising candidate for further in vivo studies. Using two mouse models of acute ulcerative colitis (UC) induced by the administration of dextran sulfate sodium (DSS) or oxazolone (OXA), 18 dose-dependently showed a better therapeutic effect than the positive control drug tofacitinib. Additionally, after long-term administration for 32 days, 18 displayed low toxicity to mice and a high safety profile. Taken together, these findings suggest that 18 is a JAK1/TYK2 dual inhibitor with therapeutic effects superior to those of tofacitinib in the treatment of IBD. Moreover, 18 is also a suitable clinical candidate for further investigation in diseases with strong involvement from interferon and/or IL-12/IL-23 in their pathogenesis. This study confirmed the therapeutic effect and long-term safety of inhibiting JAK1 and TYK2 to treat IBD.

Sulfidated microscale zero-valent iron/reduced graphene oxide composite (S-mZVI/rGO) for enhanced degradation of trichloroethylene: The role of hydrogen spillover.

Atomic hydrogen (H*) has long been thought to play an important role in the dechlorination of trichloroethylene (TCE) by carbon-supported zero-valent iron (ZVI), which offers an alternative pathway for TCE dechlorination. Herein, we demonstrate that the reductive dechlorination of TCE by sulfidated microscale ZVI (S-mZVI) can be further enhanced by promoting the formation of H* through the introduction of reduced graphene oxide (rGO). The completely degradation of 10 mg/L TCE can be achieved by S-mZVI/rGO within 24 h, which was 3.3 times faster than that of S-mZVI. The change in the distribution of TCE degradation products over time suggests that the introduction of rGO leads to a change in the dechlorination pathway. The percentage of ethane in the final products of TCE degradation by S-mZVI/rGO was 34.3 %, while that of S-mZVI was only 21.9 %. The electrochemical tests confirmed the occurrence of hydrogen spillover in the S-mZVI/rGO composite, which promoted the reductive dechlorination of TCE by H*. Although the S-mZVI/rGO composite had stronger hydrogen evolution propensity than S-mZVI, the S-mZVI/rGO composite still exhibited higher electron utilization efficiency than S-mZVI thanks to the increased utilization of hydrogen.

Strong influence of degree of substitution on carboxymethyl cellulose stabilized sulfidated nanoscale zero-valent iron.

Carboxymethyl cellulose (CMC) has been widely adopted as stabilizer to enhance the subsurface mobility of nanoscale zerovalent iron (nZVI). However, CMC surface modification also cause severe decrease of the longevity and electron utilization efficiency (εe) of nZVI, which is still not well understood. In this study, we demonstrate the negative influence of CMC on the properties of sulfidated nZVI (S-nZVI) could be reversed by increasing the degree of substitution (D.S.) of CMC. Consistent with previous study, the sample CMC-S-nZVI prepared with commercial CMC with degree of substitution (D.S.) of 0.75 exhibited a considerable low longevity of 33 days with εe of 4.5%, much lower than that of sulfidated nZVI (S-nZVI, 113 days and 13%). In sharp contrast, the sample HCMC-S-nZVI synthesized with CMC with super high D.S. of 1.76 demonstrated significantly enhanced longevity of 139 days and εe of 20%. The enhancement was attributed to compatible molecular structure of CMC with super high D.S. Moreover, the HCMC-S-nZVI also exhibited higher mobility in porous media than CMC-S-nZVI. Our work provides a feasible way to prepare S-nZVI with desired properties including high subsurface transportability, high longevity and high εe.