The active ClpP protease from M. tuberculosis is a complex composed of a heptameric ClpP1 and a ClpP2 ring

Mycobacterium tuberculosis (Mtb) contains two clpP genes, both of which are essential for viability. We expressed and purified Mtb ClpP1 and ClpP2 separately. Although each formed a tetradecameric structure and was processed, they lacked proteolytic activity. We could, however, reconstitute an active, mixed ClpP1P2 complex after identifying N-blocked dipeptides that stimulate dramatically (>1000-fold) ClpP1P2 activity against certain peptides and proteins. These activators function cooperatively to induce the dissociation of ClpP1 and ClpP2 tetradecamers into heptameric rings, which then re-associate to form the active ClpP1P2 2-ring mixed complex. No analogous small molecule-induced enzyme activation mechanism involving dissociation and re-association of multimeric rings has been described. ClpP1P2 possesses chymotrypsin and caspase-like activities, and ClpP1 and ClpP2 differ in cleavage preferences. The regulatory ATPase ClpC1 was purified and shown to increase hydrolysis of proteins by ClpP1P2, but not peptides. ClpC1 did not activate ClpP1 or ClpP2 homotetradecamers and stimulated ClpP1P2 only when both ATP and a dipeptide activator were present. ClpP1P2 activity, its unusual activation mechanism and ClpC1 ATPase represent attractive drug targets to combat tuberculosis.     

Design,synthesis and biological evaluation of novel HIV-1 protease inhibitors with pentacyclic triterpenoids as P2-ligands

The design, synthesis and SAR study of a new series of HIV-1 protease inhibitors with pentacyclic triterpenoids as P2 ligands and phenylsulfonamide as P2′ ligands were discussed. These compounds exhibited micromolar inhibitory potency, among which compound T1c displayed HIV-1 protease inhibition with IC₅₀ values of 0.12?μM, which was 67 times the inhibitory activity of its raw material Ursolic acid (8.0?μM).     

Design,synthesis, and biological evaluation of novel triazoloquinazolinone derivatives as SHP2 protein inhibitors

A novel series of triazoloquinazolinone derivatives were designed, synthesised, and evaluated for their in vitro biological activities against the SHP2 protein. Moreover, some compounds were evaluated against A375 cells. The results revealed that target compounds possessed moderate to excellent inhibitory activity against SHP2 protein, whereas compounds 12f, 12l, 12j, 17e, and 17f have strong antiproliferative activity on A375 cells. The compound 12l showed remarkable cytotoxicity against A375 cells and a strong inhibitory effect against SHP2 protein when compared with SHP244. The structure-activity relationships (SARs) indicated that electron-donating groups (EDGs) on phenyl rings are beneficial for improving the antitumor activity; compounds with a hydroxyl substituent at the 2-position of phenyl ring exhibited superior activities than compounds with a substituent at the 4-position. In addition, compound 12l displayed improved physicochemical properties as well as metabolic stability compared to SHP244. Our efforts identified 12l as a promising SHP2 protein inhibitor, warranting its further investigation.     

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 and biological evaluation of novel pteridinone derivatives possessing a hydrazone moiety as potent PLK1 inhibitors

A series of novel pteridinone derivatives possessing a hydrazone moiety were designed, synthesized and evaluated for their biological activity. Most of the synthesized compounds demonstrated moderate to excellent activity against A549, HCT116 and PC-3 cancer cell lines. In particular, compound L₁₉ exhibited the most potent antiproliferative effects on three cell lines with IC₅₀ values of 3.23 μM, 4.36 μM and 8.20 μM, respectively. In kinase assays, the compound L₁₉ also showed potent inhibition activity toward PLK1 with % inhibition values of 75.1. Further mechanism studies revealed that compound L₁₉ significantly inhibited proliferation of HCT-116 cell lines, induced a great decrease in mitochondrial membrane potential resulting in apoptosis of cancer cells, inhibited the migration of tumor cells, and arrested G1 phase of HCT116 cells.     

Design,synthesis and biological evaluation of matrine derivatives as potential anticancer agents

Using matrine (1) as the lead compound, a series of new 14-(N-substituted-2-pyrrolemethylene) matrine and 14-(N-substituted-indolemethylene) matrine derivatives was designed and synthesized for their potential application as anticancer agents. The structure of these compounds was characterized by ¹H NMR, ¹³C NMR and ESI-MS spectral analyses. The target compounds were evaluated for their in vitro cytotoxicity against three human cancer cell lines (SMMC-7721, A549 and CNE2). The results revealed that compound A6 and B21 displayed the most significant anticancer activity against three cancer cell lines with IC₅₀ values in range of 3.42–8.05?μM, which showed better activity than the parent compound (Matrine) and positive control Cisplatin. Furthermore, the Annexin V-FITC/PI dual staining assay revealed that compound A6 and B21 could significantly induce the apoptosis of SMMC-7721 and CNE2 cells in a dose-dependent manner. The cell cycle analysis also revealed that compound A6 could cause cell cycle arrest of SMMC-7721 and CNE2 cells at G2/M phase.     

Design,synthesis, biological evaluation and molecular modelling studies of novel quinoline derivatives against Mycobacterium tuberculosis

We herein describe the synthesis and antimycobacterial activity of a series of 27 different derivatives of 3-benzyl-6-bromo-2-methoxy-quinolines and amides of 2-[(6-bromo-2-methoxy-quinolin-3-yl)-phenyl-methyl]-malonic acid monomethyl ester. The antimycobacterial activity of these compounds was evaluated in vitro against Mycobacterium tuberculosis H37Rv for nine consecutive days upon a fixed concentration (6.25 μg/mL) at day one in Bactec assay and compared to untreated TB cell culture as well as one with isoniazide treated counterpart, under identical experimental conditions. The compounds 3, 8, 17 and 18 have shown 92–100% growth inhibition of mycobacterial activity, with minimum inhibitory concentration (MIC) of 6.25 μg/mL. Based on our molecular modelling and docking studies on well-known diarylquinoline antitubercular drug R207910, the presence of phenyl, naphthyl and halogen moieties seem critical. Comparison of docking studies on different stereoisomers of R207910 as well as compounds from our data set, suggests importance of electrostatic interactions. Further structural analysis of docking studies on our compounds suggests attractive starting point to find new lead compounds with potential improvements.     

Design,synthesis and biological evaluation of novel aryl-acrylic derivatives as novel indoleamine-2,3-dioxygenase 1 (IDO1) inhibitors

Two series of novel aryl-acrylic derivatives were designed, synthesized, and screened in enzymatic and cellular inhibitory activities. All compounds showed moderate to significant potency. The SAR analyses indicated that the semicarbazone linker is better than the 1,2,3-triazole linker. Among semicarbazone compounds that R₁ bearing di-chain amino groups exhibited superior activities to those with morpholino group. Furthermore, compounds with electron-withdrawing groups at the 2-position or 4-position on the terminal phenyl ring were more active. Among these, compounds 7g, 7i, 7m and 7n exhibited the inhibitory potency in the low micromolar range and displayed negligible level of cytotoxicity against normal HeLa cells. In addition, the study suggested that the aryl-acrylic is an interesting novel scaffold for IDO1 inhibition for further development.     

Design,synthesis and biological evaluation of Lenalidomide derivatives as tumor angiogenesis inhibitor

Lenalidomide is a type of immunomodulatory agent with anti-tumor activity by mainly expressed in the anti-angiogenesis. In order to enhance the pharmacological activity of Lenalidomide, a series of Lenalidomide derivatives were designed as tumor angiogenesis inhibitors. The potential anti-angiogenesis targets of Lenalidomide derivatives were virtual screened on Auto-Dock 4.0 by using reverse docking method. The six target proteins, such as vascular endothelial growth factor receptor, epidermal growth factor receptor, fibroblast growth factor receptor, BCR-ABL tyrosine kinase, p38 mitogen activated protein kinase and metal protein kinase, were chosen as the targets. The Lenalidomide derivatives were synthesized by alkylated, acylated or sulfonylated Lenalidomide and verified by the ¹H NMR, ¹³C NMR and LC–MS. Their anti-cancer activities were detected by using CCK-8 in the esophageal carcinoma cell line EC9706. The results indicate that the inhibitory activities of Lenalidomide derivatives were higher than that of Lenalidomide.     

Synthesis and biological evaluation of novel indole-pyrazoline hybrid derivatives as potential topoisomerase 1 inhibitors

A series of novel indole-pyrazoline hybrid derivatives were designed, synthesized, and evaluated for topoisomerase 1 (Top1) inhibitory activity. Top1-mediated relaxation assays showed that our synthesized compounds had variable Top1 inhibitory activity. Among these compounds, 3-(5-(naphthalen-1-yl)-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl)-1-(phenylsulfonyl)-1H-indole (6n) was found to be a strong Top1 inhibitor with better inhibitory activity than CPT and hit compounds. Our further experiments rationalized the mode of action for this new type of inhibitors, which showed no significant binding to supercoiled DNA.     

Design,synthesis and biological evaluation of pyrimidine-based derivatives as VEGFR-2 tyrosine kinase inhibitors

Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in tumor angiogenesis, and inhibition of the VEGFR-2 signaling pathway has already become an attractive approach for cancer therapy. In this study, a novel pyrimidine-based derivative 7j was designed as lead compound, and three series of potent VEGFR-2 inhibitors were synthesized and biologically evaluated against A549 and HepG2 cell lines. Compounds 7d, 9s and 13n exhibited superior inhibitory activities against A549 cell with IC₅₀ ranged from 9.19 to 13.17 μM and HepG2 cell with IC₅₀ ranged from 11.94 to 18.21 μM compared to those of Pazopanib (IC₅₀ = 21.18 and 36.66 μM). In addition, molecular docking study was performed to investigate the binding capacity and binding mode between target compounds and VEGFR-2.     

Design,synthesis and biological evaluation of novel triazole,urea and thiourea derivatives of quinoline against Mycobacterium tuberculosis

A new series of 20 quinoline derivatives possessing triazolo, ureido and thioureido substituents have been synthesized and their antimycobacterial properties have been evaluated. Compounds 10, 22 and 24 inhibited Mycobacterium tuberculosis H37Rv up to 96%, 98% and 94% respectively, at a fixed concentration of 6.25 μg/mL. Minimum inhibitory concentration of 3.125 μg/mL was obtained for compound 10 and 24, while for compound 22 it was 6.25 μg/mL. Molecular docking calculations suggest critical hydrogen bonding and electrostatic interactions between polar functional groups (such as quinoline-nitrogen, urea-carbonyl and hydroxyl) of anti-mycobacterial (anti-TB) compounds and amino acids (Arg186 and Glu61) of ATP-synthase of M. tuberculosis, could be the probable reason for observed anti-mycobacterial action.     

Synthesis and biological evaluation of novel cYY analogues targeting Mycobacterium tuberculosis CYP121A1

The rise in multidrug resistant (MDR) cases of tuberculosis (TB) has led to the need for the development of TB drugs with different mechanisms of action. The genome sequence of Mycobacterium tuberculosis (Mtb) revealed twenty different genes coding for cytochrome P450s. CYP121A1 catalyzes a CC crosslinking reaction of dicyclotyrosine (cYY) producing mycocyclosin and current research suggests that either mycocyclosin is essential or the overproduction of cYY is toxic to Mtb. A series of 1,4-dibenzyl-2-imidazol-1-yl-methylpiperazine derivatives were designed and synthesised as cYY mimics. The derivatives substituted in the 4-position of the phenyl rings with halides or alkyl group showed promising antimycobacterial activity (MIC 6.25?μg/mL), with the more lipophilic branched alkyl derivatives displaying optimal binding affinity with CYP121A1 (ⁱPr K_D?=?1.6?μM; ^tBu K_D?=?1.2?μM). Computational studies revealed two possible binding modes within the CYP121A1 active site both of which would effectively block cYY from binding.     

Design,synthesis, and biological evaluation of 1,2,4-triazole bearing 5-substituted biphenyl-2-sulfonamide derivatives as potential antihypertensive candidates

A series of novel 1,2,4-triazole bearing 5-substituted biphenyl-2-sulfonamide derivatives were designed and synthesized to develop new angiotensin II subtype 2 (AT₂) receptor agonists as novel antihypertensive candidates. It was found that 14f (IC₅₀ = 0.4 nM) and 15e (IC₅₀ = 5.0 nM) displayed potent AT₂ receptor affinity and selectivity in binding assays. Biological evaluation in vivo suggested that 14f is obviously superior to that of reference drug losartan in RHRs, and meanwhile, 14f has no significant impact on heart rate. The interesting activities of these compounds may make them promising candidates as antihypertensive agents.     

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 4-phenoxyquinoline derivatives as potent c-Met kinase inhibitor

A series of novel 4-phenoxyquinoline derivatives containing 3-oxo-3,4-dihydro-quinoxaline moiety were synthesized and evaluated for their antiproliferative activity against five human cancer cell lines (A549, H460, HT-29, MKN-45 and U87MG) in vitro. Most of the tested compounds exhibited more potent inhibitory activities than the positive control foretinib. Compound 1b, 1s and 1t were further examined for their inhibitory activity against c-Met kinase. The most promising compound 1s (with c-Met IC₅₀ value of 1.42 nM) showed remarkable cytotoxicity against A549, H460, HT-29, MKN45 and U87MG cell lines with IC₅₀ values of 0.39 μM, 0.18 μM, 0.38 μM, 0.81 μM, respectively. Their preliminary structure-activity relationships (SARs) study indicated that the replacement of the aromatic ring with the cyclohexane improved their antiproliferative activity.     

Design,synthesis and biological evaluation of benzimidazole derivatives as novel human Pin1 inhibitors

In this work, a series of novel benzimidazole derivatives were designed and synthesized as Pin1 inhibitors. Protease-coupled assay was used to investigate the Pin1 inhibitory potency of all synthesized compounds. Thirteen of them showed preferable Pin1 inhibitory effects with IC₅₀ values lower than 5 μM, and 12a, 15b, 15d and 16c exhibited the most promising Pin1 inhibitory activity at low micromolar level (0.33–1.00 μM) than the positive control compound Juglone. Flow cytometry results showed that treating PC-3 cells with 16c caused slight cycle arrest in a concentration-dependent manner. The structure-activity relationships of R¹, R², R³ and linker of the benzimidazole derivatives were analyzed in detail, which would help further exploration of new Pin1 inhibitors.     

Design,synthesis and biological evaluation of novel L-isoserine tripeptide derivatives as aminopeptidase N inhibitors

Aminopeptidase N (APN/CD13) is one of the essential proteins for tumour invasion, angiogenesis and metastasis as it is over-expressed on the surface of different tumour cells. Based on our previous work that L-isoserine dipeptide derivatives were potent APN inhibitors, we designed and synthesized L-isoserine tripeptide derivatives as APN inhibitors. Among these compounds, one compound 16l (IC₅₀?=?2.51?±?0.2 µM) showed similar inhibitory effect compared with control compound Bestatin (IC₅₀?=?6.25?±?0.4 µM) and it could be used as novel lead compound for the APN inhibitors development as anticancer agents in the future.     

Design,synthesis and biological evaluation of novel quinazoline derivatives as potential anti-cancer agents

Twenty-two quinazoline derivatives have been synthesised and examined for their anti-tumour activity against three tumour cell lines, namely human breast cancer cell line (MCF-7), human cervical cancer cell line (HeLa) and human hepatoma cell line (HepG2). Twelve of the tested compounds have shown promising anti-tumour activity with an IC₅₀ range of 5.0–9.7 µg/mL. Regarding the spectrum of activity, five compounds exhibited interesting anti-proliferative properties against the three tested cell lines comparable to the reference drug (dasatinib).     

Design,synthesis and biological evaluation of novel 3-substituted 4-anilino-coumarin derivatives as antitumor agents

Various 3-substituted 4-anilino-coumarin derivatives have been designed, synthesized and their anti-proliferative properties have been studied. The in vitro cytotoxicity screening was performed against MCF-7, HepG2, HCT116 and Panc-1 cancer cell lines by MTT assay. Most of the synthesized compounds exhibited comparable anti-proliferative activity to the positive control 5-Fluorouracil against these four tested cancer cell lines. Among the different substituents at C-3 position of coumarin scaffold, 3-trifluoroacetyl group showed the most promising results. Especially, compounds 33d (IC₅₀ = 16.57, 5.45, 4.42 and 5.16 μM) and 33e (IC₅₀ = 20.14, 6.71, 4.62 and 5.62 μM) showed excellent anti-proliferative activities on MCF-7, HepG2, HCT116 and Panc-1 cell lines respectively. In addition, cell cycle analysis and apoptosis activation revealed that 33d induced G2/M phase arrest and apoptosis in MCF-7 cells in a dose-dependent manner. Low toxicity of compounds 33d and 33e was observed against human umbilical vein endothelial cells (HUVECs), suggesting their acceptable safety profiles in normal cells. Furthermore, the results of in silico ADME studies indicated that both 33d and 33e exhibited good pharmacokinetic properties.