Synthesis and evaluation of N-acyl-substituted 1,2-benzisothiazol-3-one derivatives as caspase-3 inhibitors

A small molecule library of N-acyl-substituted 1,2-benzisothiazol-3-one derivatives has been synthesized and evaluated as inhibitors of caspase-3 and -7, in which some of them showed nanomolar potency against caspase-3 and -7 in vitro. Meanwhile, in 10 μM concentration, both compounds 24 and 25 showed significant protection against apoptosis in camptothecin-induced Jurkat T cells system. The docking studies predicted the interactions and binding modes of the synthesized inhibitors in the caspase-3 active site.     

1,2-Benzisothiazol-3-one derivatives as a novel class of small-molecule caspase-3 inhibitors

A novel series of 1,2-benzisothiazol-3-one derivatives was synthesized and their biological activities were evaluated for inhibiting caspase-3 and -7 activities, in which some of them showed low nanomolar potency against caspase-3 in vitro and significant protection against apoptosis in a camptothecin-induced Jurkat T cells system. Among the tested compounds, compound 5i exhibited the most potent caspase-3 inhibitory activity (IC₅₀ = 1.15 nM). The molecular docking predicted the interactions and binding modes of the synthesized inhibitor in the caspase-3 active site.     

Isatin 1,2,3-triazoles as potent inhibitors against caspase-3

Sixteen disubstituted 1,2,3-triazoles were prepared using the Huisgen cycloaddition reaction and evaluated as inhibitors against caspase-3. The two most potent inhibitors were found to be (S)-1-((1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-1H-1,2,3-triazol-4-yl)methyl)-5-((2-(methoxymethyl)pyrrolidin-1-yl)sulfonyl)indoline-2,3-dione (7f) and (S)-1-((1-benzyl-1H-1,2,3-triazol-5-yl)methyl)-5-((2-(methoxymethyl)pyrrolidin-1-yl)sulfonyl)indoline-2,3-dione (8g) with IC₅₀-values of 17 and 9 nM, respectively. Lineweaver-Burk plots revealed that these two triazoles show competitive inhibitory mechanism against caspase-3.     

Synthesis and evaluation of isatin analogs as caspase-3 inhibitors: introduction of a hydrophilic group increases potency in a whole cell assay

A series of isatin analogs containing a hydrophilic group, including a pyridine ring, ethylene glycol group, and a triazole ring, have been synthesized, and their inhibition potency for caspase-3 was measured both in vitro (i.e., recombinant enzyme) and in whole cells (HeLa cells). The analogs having a hydrophilic group, including 12, 13, 16, 38, and 40, have dramatically increased activity in vitro and in HeLa cells compared to the corresponding unsubstituted N-phenyl isatin analogs.     

Design,synthesis and evaluation of phthalazinone thiohydantoin-based derivative as potent PARP-1 inhibitors

Two new series of compounds were designed and synthesized as potent PARP-1 inhibitors. These compounds were evaluated for PARP-1 enzyme and cellular inhibitory activities. All efforts lead to the identification of 9k (named as LG-12) with efficient potency both for PARP-1 and BRCA1 deficient MDA-MB-436 cells. Additionally, the novel PARP-1 inhibitor LG-12 is an efficient chemosensitizer, which could potentiate the anti-cancer effect of TMZ. Our data presented herein provide a comprehensive preclinical in vitro evaluation of the potential therapeutic efficacy and potency of chemotherapeutic agent-PARP-1 inhibitor combinations for LG-12. The combined results indicated that LG-12 could be a promising candidate for further study.     

Design,synthesis and biological evaluation of novel oseltamivir derivatives as potent neuraminidase inhibitors

Neuraminidase (NA) is one of the particular potential targets for novel antiviral therapy. In this work, a series of neuraminidase inhibitors with the cyclohexene scaffold were studied based upon the combination of 3D-QSAR, molecular docking, and molecular dynamics techniques. The results indicate that the built 3D-QSAR models yield reliable statistical information: the correlation coefficient (r²) and cross-validation coefficient (q²) of CoMFA (comparative molecular field analysis) are 0.992 and 0.819; the r² and q² of CoMSIA (comparative molecular similarity analysis) are 0.992 and 0.863, respectively. Molecular docking and MD simulations were conducted to confirm the detailed binding mode of enzyme-inhibitor system. The new NA inhibitors had been designed, synthesized, and their inhibitory activities against group-1 neuraminidase were determined. One agent displayed excellent neuraminidase inhibition, with IC₅₀ value of 39.6?μM against NA, while IC₅₀ value for oseltamivir is 61.1?μM. This compound may be further investigated for the treatment of infection by the new type influenza virus.     

Design,synthesis and biological evaluation of novel zanamivir derivatives as potent neuraminidase inhibitors

Neuraminidase (NA) is an important antiviral drug target. Zanamivir is one of the most potent NA inhibitors. In this paper, a series of zanamivir derivatives as potential NA inhibitors were studied by combination of molecular modeling techniques including 3D-QSAR, molecular docking, and molecular dynamics (MD) simulation. The results show that the best CoMFA (comparative molecular field analysis) model has q²?=?0.728 and r²?=?0.988, and the best CoMSIA (comparative molecular similarity indices analysis) model has q²?=?0.750 and r²?=?0.981, respectively. The built 3D-QSAR models show significant statistical quality and excellent predictive ability. Seven new NA inhibitors were designed and predicted. 20?ns of MD simulations were carried out and their binding free energies were calculated. Two designed compounds were selected to be synthesized and biologically evaluated by NA inhibition and virus inhibition assays. One compound (IC₅₀?=?0.670?µM, SI?>?149) exhibits excellent antiviral activity against A/WSN/33 H1N1, which is superior to the reference drug zanamivir (IC₅₀?=?0.873?µM, SI?>?115). The theoretical and experimental results may provide reference for development of new anti-influenza drugs.     

Design,synthesis, anticancer evaluation and docking studies of new pyrimidine derivatives as potent thymidylate synthase inhibitors

Cancer is a perplexing and challenging problem for researchers. In this study, a series of 6-aryl-5-cyano-pyrimidine derivatives were designed, synthesized and evaluated for their anticancer activity against HePG-2, MCF-7 and HCT-116 cell lines. Compounds 2, 3d, 4a-c, 5, 8 and 12 displayed high anticancer activity, comparable to that of 5-fluorouracil. Additionally, those compounds with effective anticancer activity were further assessed for their ability to inhibit thymidylate synthase (TS) enzyme. All the tested compounds demonstrated a marked TS inhibitory activity (33.66–74.98%), with IC₅₀ ranging from 3.89 to 15.74 nM. Moreover, apoptosis studies were conducted on the most potent compound 8, to evaluate its proapoptotic potential. Interestingly, compound 8 induced the level of active caspase 3, and elevated the Bax/Bcl2 ratio 44 folds in comparison to the control. Finally, a molecular docking study was conducted to detect the probable interaction between the active compounds and the thymidylate synthase active site.     

Discovery of substituted 6-pheny-3H-pyridazin-3-one derivatives as novel c-Met kinase inhibitors

We report a series of phenyl substituted pyridazin-3-ones substituted with morpholino-pyrimidines. The SAR of the phenyl was explored and their c-Met kinase and cell-based inhibitory activity toward c-Met driven cell lines were evaluated. Described herein is a potent c-Met inhibitor by structural modification of the parent morpholino-pyridazinone scaffold, with particular focus on the phenyl and pyrimidine substituents.     

Design, synthesis and evaluation of flavonoid derivatives as potent AChE inhibitors

A new series of flavonoid derivatives have been designed, synthesized and evaluated as potent AChE inhibitors. Most of them showed more potent inhibitory activities to AChE than rivastigmine. The most potent inhibitor isoflavone derivative 10d inhibit AChE with a IC₅₀ of 4 nM and showed high BChE/AChE inhibition ratio (4575-fold), superior to donepezil (IC₅₀ = 12 nM, 389-fold). Molecular docking studies were also performed to explore the detailed interaction with AChE.     

Design,synthesis, and biological evaluation of novel 3-pyrrolo[b]cyclohexylene-2-dihydroindolinone derivatives as potent receptor tyrosine kinase inhibitors

A novel series of 3-pyrrolo[b]cyclohexylene-2-dihydroindolinone derivatives targeting VEGFR-2, PDGFR-β and c-Kit kinases were designed and synthesized. The molecular design was based on the SAR features of indolin-2-ones as kinase inhibitors. SAR study of the series allowed us to identify compounds possessing more potent inhibitory activities against the three kinases than sunitinb with IC₅₀ values in the low nanomolar range in vitro. Additionally, some compounds also showed favorable antiproliferative activities against a panel of cancer cell lines (BXPC-3, T24, BGC, HEPG2 and HT29).     

Design,synthesis and biological evaluation of anthranilamide derivatives as potent SMO inhibitors

A series of anthranilamide derivatives were designed and synthesized as novel smoothened (SMO) inhibitors based on the SMO inhibitor taladegib (LY2940680), which can also inhibit the SMO-D473H mutant, via a ring-opening strategy. The phthalazine core in LY2940680 was replaced with anthranilamide, which retained the inhibitory activity towards the hedgehog (Hh) signaling pathway as evidenced by a dual luciferase reporter gene assay. Compound 12a displayed the best inhibitory activity against the Hh signaling pathway with IC₅₀ value of 34.09 nM, and exhibited better proliferation inhibitory activity towards the Daoy cell line (IC₅₀ = 0.48 μM) than LY2940680 (IC₅₀ = 0.79 μM).     

Design,synthesis and biological evaluation of indeno[1,2-d]thiazole derivatives as potent histone deacetylase inhibitors

Novel indeno[1,2-d]thiazole hydroxamic acids were designed, synthesized, and evaluated for histone deacetylases (HDACs) inhibition and antiproliferative activities on tumor cell lines. Most of the tested compounds exhibited HDAC inhibition and antiproliferative activity against both MCF7 and HCT116 cells with GI₅₀ values in the sub-micromolar range. Among them, compound 6o showed good inhibitory activity against pan-HDAC with IC₅₀ value of 0.14 μM and significant growth inhibition on MCF7 and HCT116 cells with GI₅₀ values of 0.869 and 0.535 μM, respectively.     

Dykellic acid inhibits drug-induced caspase-3-like protease activation

Dykellic acid is a novel microbial metabolite isolated from the broth of Westerdykella multispora F50733. Investigations on the molecular function of dykellic acid revealed that this compound partially inhibits calcium influx, resulting in a decrease in Ca(2+)-dependent endonuclease activation and DNA fragmentation induced by camptothecin. In our experiments, active caspase-3-like protease cleavage of procaspase-3, PARP, and cytosolic cytochrome c was inhibited by dykellic acid in a concentration-dependent manner when the apoptosis was induced by camptothecin as well as doxorubicin. We confirmed that dykellic acid did not bind to camptothecin using surface plasmon resonance analysis. These results suggest that dykellic acid inhibits drug-induced apoptosis via a caspase-3-like protease-suppressing mechanism. Our data provide important information on the mechanism of action of dykellic acid and indicate that this compound may be employed in the treatment of specific caspase-3-like protease-mediated diseases.     

Design, synthesis, and evaluation of 2-phenoxy-indan-1-one derivatives as acetylcholinesterase inhibitors

A series of 2-phenoxy-indan-1-one derivatives have been designed, synthesized, and tested as acetylcholinesterase inhibitors. The most potent compound exhibited high AChE inhibitory activity (IC50 = 50 nM), and the molecular docking study indicated that it was nicely accommodated by AChE.     

Design,synthesis, and anti-cancer evaluation of new pyrido[2,3-d]pyrimidin-4(3H)-one derivatives as potential EGFRWT and EGFRT790M inhibitors and apoptosis inducers

A new series of pyrido[2,3-d]pyrimidin-4(3H)-one derivatives having the essential pharmacophoric features of EGFR inhibitors has been designed and synthesised. Cell viability screening was performed for these compounds against A-549, PC-3, HCT-116, and MCF-7 cell lines at a dose of 100 μM. The highest active derivatives (8a, 8 b, 8d, 9a, and 12b) were selected for IC₅₀ screening. Compounds 8a, 8 b, and 9a showed the highest cytotoxic activities and were further investigated for wild EGFR^WT and mutant EGFR^T790M inhibitory activities. Compound 8a showed the highest inhibitory activities against EGFR^WT and EGFR^T790M with IC₅₀ values of 0.099 and 0.123 µM, respectively. In addition, it arrested the cell cycle at pre-G1 phase and induced a significant apoptotic effect in PC-3 cells. Furthermore, compound 8a induced a 5.3-fold increase in the level of caspase-3 in PC-3 cells. Finally, docking studies were carried out to examine the binding mode of the synthesised compounds against both EGFR^WT and EGFR^T790M.     

Design,synthesis and biological evaluation of novel thiazole derivatives as potent FabH inhibitors

Fatty acid biosynthesis is essential for bacterial survival. Components of this biosynthetic pathway have been identified as attractive targets for the development of new antibacterial agents. FabH, β-ketoacyl-acyl carrier protein (ACP) synthase III, is a particularly attractive target, since it is central to the initiation of fatty acid biosynthesis and is highly conserved among Gram positive and negative bacteria. Three series of Schiff bases containing thiazole template were synthesized and developed as potent inhibitors of FabH. This inhibitor class demonstrates strong antibacterial activity. Escherichia coli FabH inhibitory assay and docking simulation indicated that the compounds 11 and 18 were potent inhibitors of E. coli FabH.     

Design,synthesis and biological evaluation of spiropyrazolopyridone derivatives as potent dengue virus inhibitors

The effective treatment for dengue virus infection continues to be a challenge. We herein reported our continued SAR exploration on the spiropyrazolopyridone scaffold. Introducing different substituents at the 3́- or 5́-site of the pyrazolopyridone core or moving the benzyl chain to the adjacent nitrogen led to a significant loss of potency on DENV-2. While a narrow range of substitutions were tolerated at the para-position of the phenyl ring, di-substitution on the phenyl ring is beneficial for DENV-2 potency and has variable influences on DENV-3 potency depending on the exact compound. Among these molecules, compounds 22 (JMX0376) with 4-chloro-3-fluorobenzyl and 24 (JMX0395) with 2,4-bis(trifluoromethyl)benzyl showed the most potent and broadest inhibitory activities against DENV-1 to −3 with nanomolar to low micromolar EC₅₀ values.     

Design,synthesis, and evaluation of 4,6-diaminonicotinamide derivatives as novel and potent immunomodulators targeting JAK3

In organ transplantation, T cell-mediated immune responses play a key role in the rejection of allografts. Janus kinase 3 (JAK3) is specifically expressed in hematopoietic cells and associated with regulation of T cell development via interleukin-2 signaling pathway. Here, we designed novel 4,6-diaminonicotinamide derivatives as immunomodulators targeting JAK3 for prevention of transplant rejection. Our optimization of C4- and C6-substituents and docking calculations to JAK3 protein confirmed that the 4,6-diaminonicotinamide scaffold resulted in potent inhibition of JAK3. We also investigated avoidance of human ether-a-go-go related gene (hERG) inhibitory activity. Selected compound 28 in combination with tacrolimus prevented allograft rejection in a rat heterotopic cardiac transplantation model.     

Design,synthesis and biological evaluation of benzyloxyphenyl-methylaminophenol derivatives as STAT3 signaling pathway inhibitors

STAT3 signaling pathway has been validated as a vital therapeutic target for cancer therapy. Based on the novel STAT3 inhibitor of a benzyloxyphenyl-methylaminophenol scaffold hit (1) discovered through virtual screening, a series of analogues had been designed and synthesized for more potent inhibitors. The preliminary SAR had been discussed and the unique binding site in SH2 domain was predicted by molecular docking. Among them, compounds 4a and 4b exhibited superior activities than hit compound (1) against IL-6/STAT3 signaling pathway with IC₅₀ values as low as 7.71 μM and 1.38 μM, respectively. Compound 4a also displayed potent antiproliferative activity against MDA-MB-468 cell line with an IC₅₀ value of 9.61 μM. We believe that these benzyloxyphenyl-methylaminophenol derivatives represent a unique mechanism for interrogating STAT3 as well as a potential structure type for further exploration.