Synthesis and biological evaluation of panaxadiol ester derivatives possessing pyrazole and pyrrole moiety as HIF-1α inibitors.

Hypoxia-inducing factor-1α (HIF-1α) is overexpressed in variety of tumor patients and plays an important role in the regulation of hypoxia response in tumor cells. Therefore, its inhibitors have become one of the targets for the treatment of a variety of cancers. Two series of panaxadiol (PD) ester derivatives containing pyrazole (18a-j) and pyrrole (19a-n) moiety were synthesized and their HIF-1α inhibitory activities were evaluated. Among all the target compouds, compounds 18c, 19d, and 19n (IC50 = 8.70-10.44 µM) showed better HIF-1α inhibitory activity than PD (IC50 = 13.35 µM). None of these compounds showed cytotoxicity above 100 µM and inhibited HIF-1α transcription in a dose-dependent manner. These compounds showed good antitumor activity and provide lead compounds for further design and activity study of PD ester derivatives.

Synthesis and evaluation of the epithelial-to- mesenchymal inhibitory activity of indazole-derived imidazoles as dual ALK5/p38α MAP inhibitors.

Drugs of targeting both activin receptor-like kinase 5 (ALK5) and p38α have therapeutic advantages, making them attractive treatment options for tumors. Two series of 4-(1H-indazol-5-yl)-5-(6-methylpyridin-2-yl)-1H-imidazoles 13a-g and 4-(1-methyl-1H-indazol-5-yl)-5-(6-methylpyridin-2-yl)-1H-imidazoles 20a-g were synthesized and evaluated for ALK5 and p38α mitogen-activated protein kinase inhibitory activity. The most potent compound, 13c (J-1090), inhibited ALK5- and p38α-mediated phosphorylation with half-maximal inhibitor concentrations of 0.004 µM and 0.004 µM, respectively, in the enzymatic assay. In this study, the effectiveness of 13c in transforming growth factor (TGF-ß)-exposed U87MG cells was investigated using western blotting, immunofluorescence assays, cell migration assay, invasion assay, and RT-PCR analysis. 13c inhibited the protein expression of Slug and the protein and RNA expression of the mesenchymal-related proteins N-cadherin and vimentin. Furthermore, 13c markedly suppressed TGF-ß-induced epithelial-to-mesenchymal transition (EMT), migration, and invasion in U87MG cells. These results suggest that 13c is a novel inhibitor of ALK5 with potential utility in the treatment of human glioma.

Design, synthesis and evaluation of carbazole derivatives as potential antimicrobial agents.

Five series of novel carbazole derivatives containing an aminoguanidine, dihydrotriazine, thiosemicarbazide, semicarbazide or isonicotinic moiety were designed, synthesised and evaluated for their antimicrobial activities. Most of the compounds exhibited potent inhibitory activities towards different bacterial strains (including one multidrug-resistant clinical isolate) and one fungal strain with minimum inhibitory concentrations (MICs) between 0.5 and 16 µg/ml. Compounds 8f and 9d showed the most potent inhibitory activities (MICs of 0.5-2 µg/ml). Furthermore, compounds 8b, 8d, 8f, 8k, 9b and 9e with antimicrobial activities were not cytotoxic to human gastric cancer cell lines (SGC-7901 and AGS) or a normal human liver cell line (L-02). Structure-activity relationship analyses and docking studies implicated the dihydrotriazine group in increasing the antimicrobial potency and reducing the toxicity of the carbazole compounds. In vitro enzyme activity assays suggested that compound 8f binding to dihydrofolate reductase might account for the antimicrobial effect.

Synthesis and evaluation of HIF-1α inhibitory activities of novel panaxadiol derivatives.

Hypoxia-inducible factor 1α (HIF-1α) is a known regulator of tumor cell proliferation, migration, and angiogenesis. The presence of a high concentration of HIF-1α is positively correlated with the severity of cancer. Therefore, the inhibition of this pathway represents an important therapeutic target for the treatment of various types of cancer. Here, we designed and synthesized 30 panaxadiol (PD) derivatives and evaluated their inhibitory activities against HIF-1α transcription. Of these, compound 3l exhibited the most promising inhibitory activity (IC50 = 3.7 µM) and showed significantly decreased cytotoxicity compared with PD. Compound 9e exhibited the strongest cytotoxic effect and may be considered for further preclinical development.

Arctigenin protects against depression by inhibiting microglial activation and neuroinflammation via HMGB1/TLR4/NF-κB and TNF-α/TNFR1/NF-κB pathways.

BACKGROUND AND PURPOSE: Arctigenin, a major bioactive component of Fructus arctii, has been reported to have antidepressant-like effects. However, the mechanisms underlying these effects are still unclear. Neuroinflammation can be caused by excessive production of proinflammatory cytokines in microglia via high-mobility group box 1 (HMGB1)/TLR4/NF-κB and TNF-α/TNFR1/NF-κB signalling pathways, leading to depression. In this study, we have investigated the antidepressant mechanism of arctigenin by conducting in vitro and in vivo studies. EXPERIMENTAL APPROACH: The effects of chronic unpredictable mild stress (CUMS) on wild-type (WT) and TLR4-/- mice were examined. Antidepressant-like effects of arctigenin were tested using the CUMS-induced model of depression in WT mice. The effects of arctigenin were assessed on the HMGB1/TLR4/NF-κB and TNF-α/TNFR1/NF-κB signalling pathways in the prefrontal cortex (PFC) of mouse brain and HMGB1- or TNF-α-stimulated primary cultured microglia. The interaction between HMGB1 and TLR4 or TNF-α and TNFR1 with or without arctigenin was examined by localized surface plasmon resonance (LSPR) and co-immunoprecipitation assays. KEY RESULTS: The immobility times in the tail suspension test (TST) and forced swimming test (FST) were reduced in TLR4-/- mice, compared with WT mice. Arctigenin exhibited antidepressant-like effects. Arctigenin also inhibited microglia activation and inflammatory responses in the PFC of mouse brain. Arctigenin inhibited HMGB1 and TLR4 or TNF-α and TNFR1 interactions, and suppressed both HMGB1/TLR4/NF-κB and TNF-α/TNFR1/NF-κB signalling pathways. CONCLUSIONS AND IMPLICATIONS: Arctigenin has antidepressant-like effects by attenuating excessive microglial activation and neuroinflammation through the HMGB1/TLR4/NF-κB and TNF-α/TNFR1/NF-κB signalling pathways. This suggests that arctigenin has potential as a new drug candidate suitable for clinical trials to treat depression.

Synthesis and evaluation of the HIF-1α inhibitory activity of 3(5)-substituted-4-(quinolin-4-yl)- and 4-(2-phenylpyridin-4-yl)pyrazoles as inhibitors of ALK5.

The transcription factor hypoxia-inducible factor-1α (HIF-1α) plays an important role in apoptosis, metastasis, and proliferation and is recognized as an important potential therapeutic target for cancer. Six series of 3(5)-(6-methylpyridin-2-yl)-4-(quinolin-4-yl)pyrazoles (11a-d, 12a-d, and 18a-d) and 3(5)-(6-methylpyridin-2-yl)-4-(2-phenyl-pyridin-4-yl)pyrazoles (19a-d, 20a-d, and 21a-d) were synthesized and evaluated for activin receptor-like kinase 5 (ALK5) and HIF-1α inhibitory activity at the enzyme and cell levels. The effect of the lead compound 20d (J-1012) on HIF-1α activation in HCT116 cells was investigated. J-1012 markedly decreased the hypoxia-induced or TNF-induced accumulation of HIF-1α protein dose-dependently. Analysis revealed that J-1012 inhibited HIF-1α protein synthesis, without affecting the degradation of HIF-1α protein. Furthermore, by inhibiting the activation of HIF-1α, J-1012 suppressed the metastasis and proliferation and promoted apoptosis of HCT116 cells. These results suggest that J-1012 may be a potential therapeutic agent against human colon cancer.

Synthesis and biological evaluation of novel benzo[c][1,2,5]thiadiazol-5-yl and thieno[3,2-c]- pyridin-2-yl imidazole derivatives as ALK5 inhibitors.

Transforming growth factor (TGF-ß), a key mediator of tumor growth and metastasis, has been recognized as an important cancer drug target. A series of benzo[c][1,2,5]thiadiazol-5-yl imidazoles (14a-g) and thieno[3,2-c]-pyridin-2-yl imidazoles (20a-g) were designed, synthesized, and evaluated for their activin receptor-like kinase 5 (ALK5) activities. Among these compounds, 14c showed the highest activity (IC50 = 0.008 µM) against ALK5 kinase, which was 16.1-fold and 1.8-fold higher than those of positive control compounds LY-2157299 (IC50 = 0.129 µM) and EW-7197 (IC50 = 0.014 µM), respectively. Compound 14g (350) showed the highest selectivity index of ALK5 against p38α MAP kinase, which was significantly higher than that of positive control compounds LY-2157299 (4) and EW-7197 (211). The inhibitory effects of compound 14c on TGF-ß-induced Smad signaling and cell motility were studied in SPC-A1, HepG2 and HUVEC cells using western blot analysis and wound healing assay. ADMET prediction analysis showed that compounds 14c and 14g had good pharmacokinetics and drug-likeness behaviors.

Synthesis and evaluation of the HIF-1α inhibitory activities of novel ursolic acid tetrazole derivatives.

The hypoxia-inducible factor-1α (HIF-1α) pathway has been implicated in tumor angiogenesis, growth, and metastasis. Therefore, the inhibition of this pathway is an important therapeutic target for the treatment of various types of cancers. Here, we designed and synthesized 31 ursolic acid (UA) derivatives containing a tetrazole moiety and evaluated them for their potential anti-tumor activities as HIF-1α transcriptional inhibitors. Of these, compound 14d (IC50 0.8 ±â€¯0.2 µM) displayed the most potent activity and compounds 14a (IC50 4.7 ±â€¯0.2 µM) exhibited the most promising biological profile. Analysis of the structure-activity relationships of these compounds with HIF-1α suggested that the presence of a tetrazole group located at C-28 of the UA derivatives was critical for their inhibitory activities.

Design and Synthesis of Novel Anti-Proliferative Emodin Derivatives and Studies on their Cell Cycle Arrest, Apoptosis Pathway and Migration.

Emodin is a cell arrest and apoptosis-inducing compound that is widely distributed in different plants (rhubarb, aloe), lichens and terrestrial fungi, and also isolated from marine-derived fungi and marine sponge-associated fungi. In this study, we designed and synthesized a novel series of emodin derivatives by binding emodin to an amino acid using linkers of varying lengths and composition, and evaluated their anti-proliferative activities using HepG2 cells (human hepatic carcinoma), MCF-7 cells (human breast cancer) and human normal liver L02 cells. Most of these derivatives showed moderate to potent anti-proliferative activities. Notably, compound 7a exhibited potent anti-proliferative activity against HepG2 cells with the half maximal inhibitory concentration (IC50) value of 4.95 µM, which was enhanced 8.8-fold compared to the parent compound emodin (IC50 = 43.87 µM), and it also exhibited better selective anti-proliferative activity and specificity than emodin. Moreover, further experiments demonstrated that compound 7a displayed a significant efficacy of inducing apoptosis through mitochondrial pathway via release of cytochrome c from mitochondria and subsequent activation of caspase-9 and caspase-3, inducing cell arrest at G0/G1 phase, as well as suppression of cell migration of tumor cells. The preliminary results suggested that compound 7a could be a promising lead compound for the discovery of novel anti-tumor drugs and has the potential for further investigations as an anti-cancer drug.

Design, synthesis, and screening of novel ursolic acid derivatives as potential anti-cancer agents that target the HIF-1α pathway.

The transcription factor hypoxia-inducible factor-1α (HIF-1α) plays an important role in tumor angiogenesis, growth, and metastasis and is recognized as an important potential therapeutic target for cancer. Here, we designed and synthesized three novel series of ursolic acid derivatives containing an aminoguanidine moiety and evaluated them as HIF-1α inhibitors and anti-cancer agents using human cancer cell lines. Most of the compounds exhibited significant inhibition of HIF-1α transcriptional activity, as measured using a Hep3B cell-based luciferase reporter assay. Among these compounds, 7b was the most potent inhibitor of HIF-1α expression under hypoxic conditions (IC50 4.0 µM) and did not display significant cytotoxicity against any cell lines tested. The mechanism of action of 7b was investigated, we found that 7b downregulated HIF-1α protein expression, possibly by suppressing its synthesis, reduced production of vascular endothelial growth factor, and inhibited the proliferation of cancer cells.

Synthesis and Evaluation of 3-Substituted-4-(quinoxalin-6-yl) Pyrazoles as TGF-ß Type I Receptor Kinase Inhibitors.

The transforming growth factor-ß (TGF-ß), in which overexpression has been associated with various diseases, has become an attractive molecular target for the treatment of cancers. Thirty-two quinoxaline-derivatives of 3-substituted-4-(quinoxalin-6-yl) pyrazoles 14a⁻d, 15a⁻d, 16a⁻d, 17a⁻d, 18a⁻d, 19a⁻d, 25a, 25b, 25d, 26a, 26b, 26d, 27b, and 27d were synthesized and evaluated for their activin TGF-ß type I receptor kinase and p38α mitogen activated protein (MAP) kinase inhibitory activity in enzymatic assays. Among these compounds, the most active compound 19b inhibited TGF-ß type I receptor kinase phosphorylation with an IC50 value of 0.28 µM, with 98% inhibition at 10 µM. Compound 19b also had good selectivity index of >35 against p38α MAP kinase, with 9.0-fold more selective than clinical candidate, compound 3 (LY-2157299). A molecular docking study was performed to identify the mechanism of action of the synthesized compounds and their good binding interactions were observed. ADMET prediction of good active compounds showed that these ones possess good pharmacokinetics and drug-likeness behavior.

Synthesis and characterisation of celastrol derivatives as potential anticancer agents.

In the present study, three series of novel celastrol derivatives were designed and synthesised by modifying the carboxylic acid at the 20th position with amino acid, amine, and triazole derivatives. All the synthesised compounds were screened for their anticancer activities using MTT assay against AGS, MGC-803, SGC-7901, HCT-116, A549, HeLa, BEL-7402, and HepG-2 cell lines. Most of the synthesised compounds exhibited potent antiproliferative effects. The most promising compound 3-Hydroxy-9ß,13α-dimethyl-2-oxo-24,25,26-trinoroleana-1(10),3,5,7-tetraen-29-oic amide, N-(R)-methyl-3-(1H-indol-2-yl)propanoate (11) showed considerable high anticancer activity against AGS cell lines, with an IC50 value of 0.44 µM, and considerably higher activities against HCT-116, BEL-7402, and HepG-2 cell lines, with IC50 values of 0.78, 0.63, and 0.76 µM, respectively. The results of apoptosis tests and molecular docking study of compound 11 binding to Caspase-3 revealed that its mechanism of action with antiproliferative was possibly involved in inducing apoptosis by inducing the activation of caspase-3.

Design, synthesis, and evaluation of novel ursolic acid derivatives as HIF-1α inhibitors with anticancer potential.

Hypoxia-inducible factor-1α (HIF-1α), a key mediator in tumor metastasis and angiogenesis, is associated with poor patient prognosis and has been recognized as an important cancer drug target. In this work, four novel series of ursolic acid derivatives containing oxadiazole, triazolone, and piperazine moieties were designed, synthesized, and evaluated for anti-tumor activity as HIF-1α inhibitors. The majority of the compounds showed an excellent ability to inhibit the expression of HIF-1α. In particular, 11b inhibited HIF-1α transcriptional activity under hypoxic conditions with IC50=36.9µM. The cytotoxicity of these compounds was also assessed in human colon cancer cell HCT116 cells by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, and no compounds showed any appreciable cytotoxic activity (IC50>100µmol/L), which was lower than that of ursolic acid (IC50=23.8µmol/L). The mechanism of action of the representative compound 11b was also investigated.

Design, synthesis, and negative inotropic evaluation of 4-phenyl-1H-1,2,4-triazol-5(4H)-one derivatives containing triazole or piperazine moieties.

In this study, four novel series of 4-phenyl-1H-1,2,4-triazol-5(4H)-one derivatives containing triazole or piperazine moieties were designed, synthesized, and evaluated for negative inotropic activity by measuring the left atrium stroke volume in isolated rabbit heart preparations. Almost all of the compounds showed an ability to moderate the cardiac workload by decreasing the heart rate and contractility. Among them, 7h was found to be the most potent with a change in stroke volume of -48.22 ± 0.36% at a concentration of 3 × 10-5  mol/L (metoprolol: -9.74 ± 0.14%). The cytotoxicity of these compounds was evaluated using the human cervical cancer cell line HeLa, the liver cancer cell line Hep3B, and the human normal hepatic cell line LO2. A preliminary study of the mechanism of action for the compound 7h on the regulation of atrial dynamics with ATP-sensitive K+ channel and L-type Ca2+ channel blockers glibenclamide and nifedipine was performed in the isolated perfused beating rabbit atria.

Synthesis and biological evaluation of CHX-DAPYs as HIV-1 non-nucleoside reverse transcriptase inhibitors.

A series of new diarylpyrimidines (DAPYs) characterized by a halogen atom on the methylene linker between wing I and the central pyrimidine ring was synthesized and evaluated for their anti-HIV activity in MT-4 cell cultures. The two most promising compounds 7f and 7g showed excellent activity against wild-type HIV-1 with low nanomolar EC50 values of 0.005 and 0.009 µM, respectively, which were comparable to or more potent than all the reference drugs zidovudine (AZT), lamivudine (3TC), nevirapine (NEV), efavirenz (EFV), delaviridine (DLV) and etravirine (ETV). In particular, 7g also displayed strong activity against the double mutant strain 103N + 181C with an EC50 value of 8.2 µM. The preliminary structure-activity relationship (SAR) and molecular docking analysis of this new series of CHX-DAPYs were also investigated.

25-Methoxylprotopanaxadiol derivatives and their anti-proliferative activities.

(20R)-25-Methoxyl-dammarane-3ß,12ß,20-triol (25-OCH3-PPD) is a dammarane-type sapogenin showing anti-proliferative potential. In our study, two series of analogs substituted at the C-3 or C-3 and C-12 positions with fatty acids were prepared conveniently. The cytotoxic activity of these compounds was evaluated using four different human tumor cell lines (A549, Hela, HT-29 and MCF-7) and a normal cell line (IOSE144). As compared with 25-OCH3-PPD, compounds 1a, 1b, 2a and 2b showed better anti-proliferative activities against all tumor cell lines and all the derivatives, with low toxicities in the normal cell line. Compound 1a (C-3 monoformiate) exhibited the strongest activity with the IC50 value of 5.2 µM towards HT29 cells. The results indicated that the difference in the substituents may affect the anti-proliferative activity of the compounds. The longer the side chain of 25-OCH3-PPD is, the lower the anti-proliferative activity would be. This information may be useful for evaluating the structure-activity relationship of other dammarane-type sapogenins and for development of novel antineoplastic agents.

Synthesis and anti-tumor evaluation of novel 25-hydroxyprotopanaxadiol analogs incorporating natural amino acids.

In the current study, derivatives of 25-hydroxyprotopanaxadiol (25-OH-PPD) were prepared and their in vitro anti-tumor activities were tested on six different human tumor cell lines by standard MTT assay. The results showed that combining an ester group combined with the presence of an amino acid moiety led to a 10-fold improved anti-tumor activity. Compound 1c exhibited the best anti-tumor activity in the in vitro assays. Compounds 2c, 3c, 4c, 5c, 6c and 8b showed better anti-tumor activities compared to the parent compound 25-OH-PPD. The current results may provide useful data for researching and developing new anti-cancer agents.

Semi-synthesis and anti-tumor evaluation of novel 25-hydroxyprotopanaxadiol derivatives.

30 novel compounds have been synthesized from 25-hydroxyprotopanaxadiol (25-OH-PPD) and their in vitro anti-tumor activities were tested on three cancer cell lines and one normal cell line (IOSE144) by standard MTT assay. The results showed that compound 27 exhibited the best anti-tumor activity in the in vitro assays. Compounds 1, 2, 16, 17, 18, 27, 28 and 29 have better anti-tumor activities against MCF-7 and A549 cancer cell lines than 25-OH-PPD, together with low toxicity in the normal cell. The results may provide useful data for researching and developing new antitumor agents.

Synthesis and antitumor activity of dehydroepiandrosterone derivatives on Es-2, A549, and HepG2 cells in vitro.

A series of dehydroepiandrosterone derivatives containing an acid ester was synthesized and evaluated for their antitumor activity on ES-2, A549, and HepG2 cells by the MTT assay. Most compounds showed antitumor activity, while compounds 1c, 2i, and 2o exhibited more potential inhibitory effects compared with dehydroepiandrosterone on ES-2 cells, A549 cells, and HepG2 cells, respectively.

Synthesis and anti-tumor evaluation of panaxadiol derivatives.

A series of panaxadiol derivatives have been synthesized by the simple acylation of the 3-hydroxy group of panaxadiol. The anti-tumor activities of the synthesized compounds were evaluated against a panel of human tumor cell lines by the standard MTT assay. Compounds 2, 11, 12, 13, 14, 15 and 16 showed stronger antiproliferative activities than that of Rg3 and PD on the growth of the distinct cancer cell lines in vitro.