Design, synthesis and anticancer activity of novel dihydrobenzofuro[4,5-b][1,8]naphthyridin-6-one derivatives

On the basis of the chemical structures of psorospermin with a xanthone template and acronycine derivatives with an acridone template, rac-1 and rac-2 constructed on an 1,2-dihydrobenzofuro[4,5-b][1,8]naphthyridin-6(11H)-one scaffold were designed and synthesized as potential anticancer agents. Their anticancer activities were evaluated against five human cancer cell lines. Rac-2 showed similar anticancer activity to doxorubicin and rac-1 exhibited even higher anticancer activity against LNCaP (IC(50)=0.14 μM), DU145 (IC(50)=0.15 μM), PC3 (IC(50)=0.30 μM) and MCF-7 (IC(50)=0.26 μM) cancer lines than doxorubicin and rac-2. Also, rac-1 revealed very potent anticancer activity (IC(50)=0.15 μM) against MCF-7/ADR cell (doxorubicin-resistant breast cancer cell) lines and induced G2/M phase arrest of the cell cycle in MCF-7/ADR cells.     

Design, synthesis, and biological evaluation of callophycin A and analogues as potential chemopreventive and anticancer agents

Callophycin A was originally isolated from the red algae Callophycus oppositifolius and shown to mediate anticancer and cytotoxic effects. In our collaborative effort to identify potential chemopreventive and anticancer agents with enhanced potency and selectivity, we employed a tetrahydro-β-carboline-based template inspired by callophycin A for production of a chemical library. Utilizing a parallel synthetic approach, 50 various functionalized tetrahydro-β-carboline derivatives were prepared and assessed for activities related to cancer chemoprevention and cancer treatment: induction of quinone reductase 1 (QR1) and inhibition of aromatase, nitric oxide (NO) production, tumor necrosis factor (TNF)-α-induced NFκB activity, and MCF7 breast cancer cell proliferation. Biological results showed that the n-pentyl urea S-isomer 6a was the strongest inducer of QR1 with an induction ratio (IR) value of 4.9 at 50 μM [the concentration to double the activity (CD)=3.8 μM] and its corresponding R-isomer 6f had an IR value of 4.3 (CD=0.2 μM). The isobutyl carbamate derivative 3d with R stereochemistry demonstrated the most potent inhibitory activity of NFκB, with the half maximal inhibitory concentration (IC(50)) value of 4.8 μM, and also showed over 60% inhibition at 50 μM of NO production (IC(50)=2.8 μM). The R-isomer urea derivative 6j, having an appended adamantyl group, exhibited the most potent MCF7 cell proliferation inhibitory activity (IC(50)=14.7 μM). The S-isomer 12a of callophycin A showed the most potent activity in aromatase inhibition (IC(50)=10.5 μM).     

Antiproliferative and Apoptotic Effects of pH-Responsive Veratric Acid-Loaded Polydopamine Nanoparticles in Human Triple Negative Breast Cancer Cells

Veratric acid (VA) is plant-derived phenolic acid known for its therapeutic potential, but its anticancer effect on highly invasive triple-negative breast cancer (TNBC) is yet to be evaluated. Polydopamine nanoparticles (nPDAs) were chosen as the drug carrier to overcome VA's hydrophobic nature and ensure a sustained release of VA. We prepared pH-sensitive nano-formulations of VA-loaded nPDAs and subjected them to physicochemical characterization and in vitro drug release studies, followed by cell viability and apoptotic assays on TNBC cells (MDA-MB-231 cells). The SEM and zeta analysis revealed spherical nPDAs were uniform size distribution and good colloidal stability. In vitro drug release from VA-nPDAs was sustained, prolonged and pH-sensitive, which could benefit tumor cell targeting. MTT and cell viability assays showed that VA-nPDAs (IC50=17.6 μM) are more antiproliferative towards MDA-MB-231 cells than free VA (IC50=437.89 μM). The induction of early and late apoptosis by VA-nPDAs in the cancer cells was identified using annexin V and dead cell assay. Thus, the pH response and sustained release of VA from nPDAs showed the potential to enter the cell, inhibit cell proliferation, and induce apoptosis in human breast cancer cells, indicating the anticancer potential of VA.     

Synthesis of chalcone-amidobenzothiazole conjugates as antimitotic and apoptotic inducing agents

A series of chalcone-amidobenzothiazole conjugates (9a-k and 10a,b) have been synthesized and evaluated for their anticancer activity. All these compounds exhibited potent activity and the IC(50) of two potential compounds (9a and 9f) against different cancer cell lines are in the range of 0.85-3.3 μM. Flow cytometric analysis revealed that these compounds induced cell cycle arrest at G2/M phase in A549 cell line leading to caspase-3 dependent apoptotic cell death. The tubulin polymerization assay (IC(50) of 9a is 3.5 μM and 9f is 5.2 μM) and immuofluorescence analysis showed that these compounds effectively inhibit microtubule assembly at both molecular and cellular levels in A549 cells. Further, Annexin staining also suggested that these compounds induced cell death by apoptosis. Moreover, docking experiments have shown that they interact and bind efficiently with tubulin protein. Overall, the current study demonstrates that the synthesis of chalcone-amidobenzothiazole conjugates as promising anticancer agents with potent G2/M arrest and apoptotic-inducing activities via targeting tubulin.     

Metronidazole acid acyl sulfonamide: a novel class of anticancer agents and potential EGFR tyrosine kinase inhibitors

A series of novel metronidazole derivatives were recently reported as potent anticancer agents targeting EGFR and HER-2 by our group [Qian, Y.; Zhang, H. J.; Zhang, H.; Xu, C.; Zhao, J.; Zhu, H. L. Bioorg. Med. Chem.2010, 18, 4991]. Based on the previous results, we designed and synthesized a new series of metronidazole acid acyl sulfonamide derivatives and a new series of phenylacetyl benzenesulfonamide derivatives and their anticancer activities were evaluated as potential EGFR and HER-2 kinase inhibitors. Among all the compounds, compound 12 displayed the most potent inhibitory activity EGFR and HER-2 (IC(50)=0.39 μM for EGFR and IC(50)=1.53 μM for HER-2) and it also showed the most potent growth inhibitory activity against A549 and B16-F10 cancer cell line in vitro, with an IC(50) value of 1.26 μg/mL for A549 and 0.35 μg/mL for B16-F10. Docking simulation was further performed to position compound 12 into the EGFR active site to determine the probable binding model.     

Design and synthesis of benzo[c,d]indolone-pyrrolobenzodiazepine conjugates as potential anticancer agents

A series of benzo[c,d]indol-2(1H)one-PBD conjugates (11a-l) have been designed and synthesized as potential anticancer agents. These compounds were prepared by linking the C8-position of DC-81 with a benzo[c,d]indol-2(1H)one moiety through different alkane spacers in good yields and confirmed by (1)H NMR, mass and HRMS data. The DNA binding ability of these conjugates was evaluated by thermal denaturation studies and interestingly, compound 11l showed enhanced DNA binding ability. These compounds were also evaluated for their anticancer activity in selected human cancer cell lines of lung, skin, colon and prostate by using MTT assay method. These new conjugates showed promising anticancer activity with IC(50) values ranging from 1.05 to 36.49 μM. Moreover, cell cycle arrest in SubG1 phase was observed upon treatment of A549 cells with 1 and 2 μM (IC(50)) concentrations of compound 11l and it induced apoptosis. This is confirmed by Annexin V-FITC, Hoechst staining, caspase-3 activity as well as DNA fragmentation analysis.     

New bichalcone analogs as NF-κB inhibitors and as cytotoxic agents inducing Fas/CD95-dependent apoptosis

A series of novel bichalcone analogs were synthesized and evaluated in lipopolysaccharide (LPS)-activated microglial cells as inhibitors of nitric oxide (NO) and for in vitro anticancer activity using a limited panel of four human cancer cell lines. All analogs inhibited NO production. Compounds 4 and 11 exhibited optimal activity with IC(50) values of 0.3 and 0.5 μM, respectively, and were at least 38-fold better than the positive control. A mechanism of action study showed that both compounds significantly blocked the nuclear translocation of NF-κB p65 and up-regulation of iNOS at 1.0 μM. Compound 4 and three other analogs (3, 20, and 23) exerted significant in vitro anticancer activity GI(50) values ranging from 0.70 to 13.10 μM. A mode of action study using HT-29 colon cancer cells showed that 23 acts by inducing apoptosis signaling.     

Synthesis, molecular docking and evaluation of thiazolyl-pyrazoline derivatives as EGFR TK inhibitors and potential anticancer agents

Fourty-two thiazolyl-pyrazoline derivatives were synthesized to screen for their EGFR kinase inhibitory activity. Compound 4-(4-chlorophenyl)-2-(3-(3,4-dimethylphenyl)-5-p-tolyl-4,5-dihydro-1H-pyrazol-1-yl)thiazole (11) displayed the most potent EGFR TK inhibitory activity with IC(50) of 0.06 μM, which was comparable to the positive control. Molecular docking results indicated that compound 11 was nicely bound to the EGFR kinase. Compound 11 also showed significant antiproliferative activity against MCF-7 with IC(50) of 0.07 μM, which would be a potential anticancer agent.     

Design, synthesis and preliminary bioactivity studies of 1,3,4-thiadiazole hydroxamic acid derivatives as novel histone deacetylase inhibitors

Histone deacetylase (HDAC) inhibitors have emerged as a new class of anticancer agents, targeting the biological processes including cell cycle, apoptosis and differentiation. In the present study, a series of 1,3,4-thiadiazole based hydroxamic acids were developed as potent HDAC inhibitors. Some of them showed good inhibitory activity in HDAC enzyme assay and potent growth inhibition in some tumor cell lines. Among them, compound 6i (IC(50) = 0.089 μM), exhibited better inhibitory effect compared with SAHA (IC(50) = 0.15 μM).     

朱砂根抑制α-葡萄糖苷酶与抗氧化活性研究

对朱砂根抑制α-葡萄糖苷酶与抗氧化活性进行研究.利用96微孔板法筛选α-葡萄糖苷酶抑制活性;采用DPPH、ABTS和FRAP方法分析抗氧化活性.结果表明,乙酸乙酯部位抑制α-葡萄糖苷酶的活性最高(IC50=39.27 μg/mL),石油醚部位次之(IC50 =56.11 μg/mL),正丁醇部位活性最弱(IC50=62.05μg/mL),但均远大于阳性对照Acarbose(IC50=1081.27 μg/mL);乙酸乙酯部位抗氧化能力最强,正丁醇部位次之.乙酸乙酯部位清除DPPH自由基(IC50=38.55 mg/L)的能力比BHT( IC50=18.71 mg/L)低1/2,清除ABTS自由基的能力(IC50=3.60 mg/L)比BHT(IC50=7.44 mg/L)强,但比BHA(IC50=1.74 mg/L)弱,还原Fe3+的能力(FRAP=512.99 ±6.80 μmoTE/g)为BHT(FRAP=1581.68±97.41μmol TE/g)的1/3.结果显示朱砂根乙酸乙酯部位抑制α-葡萄糖苷酶和抗氧化活性最好.     

Somatostatin subtype-2 receptor-targeted metal-based anticancer complexes

Conjugates of a dicarba analogue of octreotide, a potent somatostatin agonist whose receptors are overexpressed on tumor cells, with [PtCl(2)(dap)] (dap = 1-(carboxylic acid)-1,2-diaminoethane) (3), [(η(6)-bip)Os(4-CO(2)-pico)Cl] (bip = biphenyl, pico = picolinate) (4), [(η(6)-p-cym)RuCl(dap)](+) (p-cym = p-cymene) (5), and [(η(6)-p-cym)RuCl(imidazole-CO(2)H)(PPh(3))](+) (6), were synthesized by using a solid-phase approach. Conjugates 3-5 readily underwent hydrolysis and DNA binding, whereas conjugate 6 was inert to ligand substitution. NMR spectroscopy and molecular dynamics calculations showed that conjugate formation does not perturb the overall peptide structure. Only 6 exhibited antiproliferative activity in human tumor cells (IC(50) = 63 ± 2 μM in MCF-7 cells and IC(50) = 26 ± 3 μM in DU-145 cells) with active participation of somatostatin receptors in cellular uptake. Similar cytotoxic activity was found in a normal cell line (IC(50) = 45 ± 2.6 μM in CHO cells), which can be attributed to a similar level of expression of somatostatin subtype-2 receptor. These studies provide new insights into the effect of receptor-binding peptide conjugation on the activity of metal-based anticancer drugs, and demonstrate the potential of such hybrid compounds to target tumor cells specifically.     

Design and synthesis of novel imidazo[4,5-b]pyridine based compounds as potent anticancer agents with CDK9 inhibitory activity

New imidazo[4,5-b]pyridine derivatives were designed, synthesized and screened for their anticancer activity against breast (MCF-7) and colon (HCT116) cancer cell lines. Nine compounds (I, II, IIIa, IIIb, IV, VI, VIIa, VIII, IX) showed significant activity against MCF-7, while six compounds (I, VIIc, VIIe, VIIf, VIII, IX) elicited a remarkable activity against HCT116. Compounds showing significant anticancer activity revealed remarkable CDK9 inhibitory potential (IC₅₀ = 0.63–1.32 μM) relative to sorafenib (IC₅₀ = 0.76 μM). Moreover, a molecular docking study was performed to illustrate the binding mode of the most active compounds in the active site of CDK9 where it revealed superior binding affinity relative to the natural ligand (T3C).     

凹叶厚朴抑制α-糖苷酶与抗氧化活性研究

首次采用96微孔板法检测贵州和河南产凹叶厚朴抑制α-葡萄糖苷酶活性;并采用DPPH、ABTS和FRAP三种方法测定其抗氧化活性.贵州产凹叶厚朴乙酸乙酯(IC50 =7.22 μg,/mL)和正丁醇提取部位(IC50=36.59 μg/mL),河南产凹叶厚朴石油醚(IC50=107.04 μg/mL)和乙酸乙酯提取部位(IC50=17.17μg/mL),它们的活性都远高于于阳性对照Acarhose( IC50=1081.27 μg/mL).贵州产凹叶厚朴乙酸乙酯提取部位清除ABTS自由基的能力最强(IC50=8.81 μg/mL),强于阳性对照BHT(IC50=11.94 μg/mL);其次为河南产凹叶厚朴乙酸乙酯提取部位(IC50=12.73 μg/mL).研究结果表明,贵州产凹叶厚朴乙酸乙酯提取部位抑制α-葡萄糖苷酶和抗氧化活性最好.     

Synthesis, biological evaluation, and molecular docking studies of N,1,3-triphenyl-1H-pyrazole-4-carboxamide derivatives as anticancer agents

A series of N,1,3-triphenyl-1H-pyrazole-4-carboxamide derivatives have been designed, synthesized and evaluated for their potential antiproliferation activity and Aurora-A kinase inhibitory activity. Among all the compounds, compound 10e possessed the most potent biological activity against HCT116 and MCF-7 cell lines with IC(50) values of 0.39±0.06μM and 0.46±0.04 μM, respectively, which were comparable to the positive control. Compound 10e also exhibited significant Aurora-A kinase inhibitory activity (IC(50)=0.16±0.03 μM). Docking simulation was performed to position compound 10e into the active site of Aurora-A kinase, in order to get the probable binding model for further study. The results of Western-blot assay demonstrated that compound 10e possessed good Aurora-A kinase inhibitory activity against HCT116. Based on the preliminary results, it is deduced that compound 10e with potent Aurora-A kinase inhibitory activity may be a potential anticancer agent.     

Synthesis, biological evaluation and molecular docking studies of 3-(1,3-diphenyl-1H-pyrazol-4-yl)-N-phenylacrylamide derivatives as inhibitors of HDAC activity

In present study, a series of 3-(1,3-diphenyl-1H-pyrazol-4-yl)-N-phenylacrylamide derivatives (5a-8d) were designed, synthesized, and evaluated for HDAC inhibition and tumor cell antiproliferation. All of these compounds are reported for the first time, the chemical structures of these compounds were confirmed by means of (1)H NMR, ESI-MS and elemental analyzes. Among the compounds, compound 8c showed the most potent biological activity against HCT116 cancer cell line (IC(50) of 0.42 ± 0.02 μM for HDAC-1 and IC(50)=0.62 ± 0.02 for HCT116). Docking simulation was performed to position compound 8c into the HDAC active site to determine the probable binding model. The results of antiproliferative assay and western-blot demonstrated that compound 8c with potent inhibitory activity in tumor growth inhibition may be a potential anticancer agent against HCT116 cancer cell.     

Design, synthesis and biological evaluation of N-phenylsulfonylnicotinamide derivatives as novel antitumor inhibitors

A series of novel N-phenylsulfonylnicotinamide derivatives (1-24) have been synthesized and evaluated as potential EGFR tyrosine kinase (TK) inhibitors. Among all the compounds, compound 10 (5-bromo-N-(4-chlorophenylsulfonyl)nicotinamide) showed the most potent growth inhibitory activity against EGFR TK and antiproliferative activity of MCF-7 cancer cell line in vitro, with IC(50) value of 0.09 and 0.07 μM. Docking simulation was performed to insert compound 10 into the EGFR TK active site to determine the probable binding model. Based on the preliminary results, compound 10 with potent inhibitory activity to tumor growth may be a potential anticancer agent.     

Design and synthesis of the novel oleanolic acid-cinnamic acid ester derivatives and glycyrrhetinic acid-cinnamic acid ester derivatives with cytotoxic properties

Oleanolic acid (OA) and glycyrrhetinic acid (GA) are natural products with anticancer effects. Cinnamic acid (CA) and its derivatives also exhibited certain anticancer activity. In order to improve the anticancer activity of OA and GA, we designed and synthesized a series of novel OA-CA ester derivatives and GA-CA ester derivatives by using molecular hybridization approach. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was used to assess their in vitro cytotoxicity on three cell lines (HeLa (cervical cancer), MCF-7 (breast cancer) and L-O2 (a normal hepatic cell)). Among the evaluated compounds, 3o presented the strongest selective cytotoxicity on HeLa cells (IC₅₀ = 1.35 μM) and showed no inhibitory activity against MCF-7 cells (IC₅₀ > 100 μM) and L-O2 cells (IC₅₀ > 100 μM), and 3e presented the strongest selective inhibition of the MCF-7 cells (IC₅₀ = 1.79 μM). What’s more, compound 2d also showed very strong selective inhibitory activity against HeLa cells (IC₅₀ = 1.55 μM). The further research using Hoechst 33342, AO/EB dual-staining, flow cytometric analysis and DCFH-DA fluorescent dye staining assay presented that 2d and 3o could induce HeLa cells apoptosis and autophagy.     

Synthesis, biological evaluation, and molecular docking studies of 1,3,4-thiadiazol-2-amide derivatives as novel anticancer agents

A series of 1,3,4-thiadiazol-2-amide derivatives (5a-5y) have been designed and synthesized, and their biological activities were also evaluated as potential antiproliferation and FAK inhibitors. Among all the compounds, 5h showed the most potent activity in vitro, which inhibited the growth of MCF-7 and B16-F10 cell lines with IC(50) values of 0.45 and 0.31 μM, respectively. Compound 5h also exhibited significant FAK inhibitory activity (IC(50)=5.32 μM). Docking simulation was performed to position compound 5h into the FAK structure active site to determine the probable binding model. The results of antiproliferative and Western-blot assay demonstrated that compound 5h possessed good antiproliferative activity. Therefore, compound 5h with potent FAK inhibitory activity may be a potential anticancer agent.     

Studies on the secondary metabolites of a Pseudoalteromonas sp. isolated from sediments collected at the northeastern coast of Brazil

Continuing search for anticancer compounds from the marine environment, we have studied microorganisms that inhabit intertidal sediments of the northeastern Brazilian coast. Of the 32 strains isolated, 13 were selected for biological evaluation of their crude extracts. The acetate extract obtained from a Gram-negative bacterium was strongly active against cancer cell lines with IC(50) values that ranged from 0.04 (HL60 leukemia cells) to 0.26 μg/ml (MDA MB-435 melanoma cells). The bacterium was identified as a Pseudoalteromonas sp. based on 16S rRNA gene sequencing. A bioassay-guided fractionation of the active extract led to the isolation of prodigiosin, a well-known tripyrrole red pigment with immunosuppressive and anticancer activities. Further experiments with ErbB-2 overexpressing cell lines, including HB4a-C3.6 (moderate overexpression), HB4a-C5.2 (high overexpression), and the parental HB4a cell line, were performed. Prodigiosin was moderately active toward HB4a cells with an IC(50) of 4.6 μg/ml, while it was 115 and 18 times more active toward HB4a-C3.6 cells (IC(50) of 0.04 μg/ml) and HB4a-C5.2 (IC(50) of 0.26 μg/ml) cells, respectively. These data suggest that, in spite of its previously described apoptosis-inducing properties, prodigiosin can selectively recognize cells overexpressing ErbB-2, which could be highly appealing in human breast cancer therapy.     

Synthesis of novel inhibitors of β-glucuronidase based on benzothiazole skeleton and study of their binding affinity by molecular docking

Benzothiazole derivatives 1-26 have been synthesized and their in vitro β-glucuronidase potential has been evaluated. Compounds 4 (IC(50)=8.9 ± 0.25 μM), 5 (IC(50)=36.1 ± 1.80 μM), 8 (IC(50)=8.9 ± 0.38 μM), 13 (IC(50)=19.4 ± 1.00 μM), 16 (IC(50)=4.23 ± 0.054 μM), and 18 (IC(50)=2.26 ± 0.06 μM) showed β-glucuronidase activity potent than the standard (d-saccharic acid 1,4-lactone, IC(50)=48.4 ± 1.25 μM). Compound 9 (IC(50)=94.0 ± 4.16 μM) is found to be the least active among the series. All active analogs were also evaluated for cytotoxicity and none of the compounds showed any cytotoxic effect. Furthermore, molecular docking studies were performed using the gold 3.0 program to investigate the binding mode of benzothiazole derivatives. This study identifies a novel class of β-glucuronidase inhibitors.