Influence of Complexation of Thiosemicarbazone Derivatives with Cu (II) Ions on Their Antitumor Activity against Melanoma Cells

A series of thiosemicarbazone derivatives was prepared and their anti-tumor activity in vitro was tested. The X-ray investigation performed for compounds T2, T3 and T5 confirmed the synthesis pathway and assumed molecular structures of analyzed thiosemicarbazones. The conformational preferences of the thiosemicarbazone system were characterized using theoretical calculations by AM1 method. Selected compounds were converted into complexes of Cu (II) ions. The effect of complexing on anti-tumor activity has been investigated. The copper(II) complexes, with Schiff bases T1, T10, T12, T13, and T16 have been synthesized and characterized by chemical and elemental analysis, FTIR spectroscopy and TGA method. Thermal properties of coordination compounds were studied using TG-DTG techniques under dry air atmosphere. G361, A375, and SK-MEL-28 human melanoma cells and BJ human normal fibroblast cells were treated with tested compounds and their cytotoxicity was evaluated with MTT test. The compounds with the most promising anti-tumour activity were then selected and their cytotoxicity was verified with cell cycle analysis and apoptosis/necrosis detection. Additionally, DNA damages in the form of a basic sites presence and the expression of oxidative stress and DNA damage response genes were evaluated. The obtained results indicate that complexation of thiosemicarbazone derivatives with Cu (II) ions improves their antitumor activity against melanoma cells. The observed cytotoxic effect is associated with DNA damage and G2/M phase of cell cycle arrest as well as disorders of the antioxidant enzymes expression.     

苦参碱衍生物的合成及抗肿瘤活性测试

以苦参碱为原料合成去氧苦参碱和苦参酸.其结构经EI-MS、1H NMR、IR和元素分析确证.采用MTT法测试所合成化合物的体外抗肿瘤活性,结果表明,去氧苦参碱抗肝癌细胞HepG2和SMMC7721的活性强于苦参碱.     

Indolocarbazole glycosides in inactive conformations

Indolocarbazole glycosides related to rebeccamycin represent a promising category of antitumor agents targeting DNA and topoisomerase I. These drugs prefer to adopt a closed conformation with an intramolecular hydrogen bond between the indole NH group and the pyranose oxygen atom. Three pairs of indolocarbazole monoglycosides bearing an NH or an N-methyl indole moiety were synthesized and their biological properties investigated at the molecular and cellular level. Replacing the indole NH proton with a methyl group reduces DNA interaction and abolishes activity against DNA topoisomerase I. Surface plasmon resonance studies performed with a pair of water-soluble indolocarbazole glycosides and two hairpin oligonucleotides containing an [AT]4 or a [CG]4 sequence indicate that both the NH and the N-methyl derivative maintain a relatively high affinity for DNA (Keq = 2 - 6 x 10(5) M(-1)) but the incorporation of the methyl group restricts access to the DNA. The number of ligand binding sites (n) on the oligonucleotides is about twice as high for the NH compound compared to its N-methyl analogue. Modeling and 1H NMR studies demonstrate that addition of the N-methyl group drives a radical change in conformation in which the orientation of the aglycone relative to the beta-glucoside is reversed. The loss of the closed conformation by the N-methyl derivatives perturbs thir ability to access DNA binding sites and prevents the drug from inhibiting topoisomerase I. As a consequence, the NH compounds exhibit potent cytotoxicity against CEM leukemia cells with an IC50 value in the 1 microM range, whereas the N-methyl analogues are 10 to 100 times less cytotoxic. These studies offer circumstantial evidence supporting the importance of the closed conformation in the interaction of indolocarbazole glycosides with their molecular targets, DNA and topoisomerase I.     

Synthesis of novel poly 2‐vinylpyridine‐mixed metal complexes and studying their effect as antitumor chemotherapeutic agents,part 2

The poly2‐vinylpyridine and cationic polymer‐mixed metal complexes (P2VPMC) have been prepared and characterized by analytical measurement such as: molecular weight, elemental analysis, IR‐spectroscopy, NMR‐spectroscopy, XRD, and UV. The degree of N‐alkylation of poly vinyl pyridine (P‐2VP) was 10% determined by chlorine content according to elemental microanalysis. Through ICP instrument the complexation between P‐2VPC and the mixed metal chlorides was proven. The structure of the samples was characterized using X‐ray diffraction. It was found that the complexes have amorphous properties. The antitumor activity of this compound was examined in vitro on cell lines. The results reflect pronounced cytotoxicity of P‐2VPMC against animal experimental EAC cells line, and human, HeLa, HCT116 and Hep‐G2, cell lines. Antitumor activity of the novel compound as applied on mice bearing Ehrlich solid carcinoma, revealed delays tumor growth compared with untreated animals and decreases tumor volume. The antitumor activity of the P2VPMC might be due to its ability to pass through the membrane and interact with, DNA causing cross‐linking action which might be the key factor for great antitumor activity of the P2VPMC compound. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Novel Bcl-2 inhibitors: Discovery and mechanism study of small organic apoptosis-inducing agents

Apoptosis as a novel target for cancer chemotherapy has generated an intense demand for new apoptosis-inducing agents. The newly revealed role of protein families involved in the apoptosis pathway, and resistance to cytotoxic therapies have opened new avenues for the development of novel anticancer strategies. We have established a novel strategy to rapidly obtain protein-targeted, instead of conventional DNA-targeted, apoptosis inducers as antitumor leads. First, a novel organic non-DNA intercalative compound S1 (8-oxo-3-thiomorpholin-4-yl-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile, M(W) = 331) was found with an IC50 of 10(-7)-10(-8) microM against diverse cancer cell lines. Further biological evaluation demonstrated that it was an apoptosis-inducer both in vivo and in vitro. The treatment of hydroperitoneum hepatoma cells (H22 cell line) with S1 at various concentrations (from 0.01 to 10 microM) for 24 h triggered these cells to enter the apoptosis process. The antitumor efficiency was also tested in the H22 xenotransplant models in mice. At a dosage of 0.3 mg kg(-1), S1 exhibited significant antitumor activity with a much longer survival time, a decrease in tumor size, and increased apoptosis cells in tumor tissue. More importantly, studies of the molecular mechanism of apoptosis induction by S1 revealed that S1 inactivated the Bcl-2 protein by binding to it, depolarizing the mitochondrial membrane, and then activating caspase 9, followed by caspase 3. Finally, structure-based virtual modification was performed by computer modeling. As a result, a derivative, S2 (8-oxo-3-[(thienylmethyl)amino]-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile, M(W) = 341) was identified that possessed a lower binding energy to Bcl-2, and demonstrated better antitumor potency, even on the Bcl-2-overexpressing human acute myeloid leukemia (HL-60) cells (IC50 = 1.3 microM) in vitro. S1 and S2 are the well-defined Bcl-2 inhibitors that give us a promising platform for the development of new therapeutic agents.     

Identification of Spiro-Fused [3-azabicyclo[3.1.0]hexane]oxindoles as Potential Antitumor Agents: Initial In Vitro Evaluation of Anti-Proliferative Effect and Actin Cytoskeleton Transformation in 3T3 and 3T3-SV40 Fibroblast

Novel heterocyclic compounds containing 3-spiro[3-azabicyclo[3.1.0]hexane]oxindole framework (4a, 4b and 4c) have been studied as potential antitumor agents. The in silico ADMET (adsorption, distribution, metabolism, excretion and toxicity) analysis was performed on 4a–c compounds with promising antiproliferative activity, previously synthetized and screened against human erythroleukemic cell line K562 tumor cell line. Cytotoxicity of 4a–c against murine fibroblast 3T3 and SV-40 transformed murine fibroblast 3T3-SV40 cell lines were evaluated. The 4a and 4c compounds were cytotoxic against 3T3-SV40 cells in comparison with those of 3T3. In agreement with the DNA cytometry studies, the tested compounds have achieved significant cell-cycle perturbation with higher accumulation of cells in G0/G1 phase. Using confocal microscopy, we found that with 4a and 4c treatment of 3T3 cells, actin filaments disappeared, and granular actin was distributed diffusely in the cytoplasm in 82–97% of cells. The number of 3T3-SV40 cells with stress fibers increased to 7–30% against 2% in control. We discovered that transformed 3T3-SV40 cells after treatment with compounds 4a and 4c significantly reduced the number of cells with filopodium-like membrane protrusions (from 86 % in control cells to 6–18% after treatment), which indirectly suggests a decrease in cell motility. We can conclude that the studied compounds 4a and 4c have a cytostatic effect, which can lead to a decrease in the number of filopodium-like membrane protrusions.     

Novel A-Ring Chalcone Derivatives of Oleanolic and Ursolic Amides with Anti-Proliferative Effect Mediated through ROS-Triggered Apoptosis

A series of A-ring modified oleanolic and ursolic acid derivatives including C28 amides (3-oxo-C2-nicotinoylidene/furfurylidene, 3β-hydroxy-C2-nicotinoylidene, 3β-nicotinoyloxy-, 2-cyano-3,4-seco-4(23)-ene, indolo-, lactame and azepane) were synthesized and screened for their cytotoxic activity against the NCI-60 cancer cell line panel. The results of the first assay of thirty-two tested compounds showed that eleven derivatives exhibited cytotoxicity against cancer cells, and six of them were selected for complete dose–response studies. A systematic study of local SARs has been carried out by comparative analysis of potency distributions and similarity relationships among the synthesized compounds using network-like similarity graphs. Among the oleanane type triterpenoids, C2-[4-pyridinylidene]-oleanonic C28-morpholinyl amide exhibited sub-micromolar potencies against 15 different tumor cell lines and revealed particular selectivity for non-small cell lung cancer (HOP-92) with a GI₅₀ value of 0.0347 μM. On the other hand, superior results were observed for C2-[3-pyridinylidene]-ursonic N-methyl-piperazinyl amide 29, which exhibited a broad-spectrum inhibition activity with GI₅₀ < 1 μM against 33 tumor cell lines and <2 μM against all 60 cell lines. This compound has been further evaluated for cell cycle analysis to decipher the mechanism of action. The data indicate that compound 29 could exhibit both cytostatic and cytotoxic activity, depending on the cell line evaluated. The cytostatic activity appears to be determined by induction of the cell cycle arrest at the S (MCF-7, SH-SY5Y cells) or G₀/G₁ phases (A549 cells), whereas cytotoxicity of the compound against normal cells is nonspecific and arises from apoptosis without significant alterations in cell cycle distribution (HEK293 cells). Our results suggest that the antiproliferative effect of compound 29 is mediated through ROS-triggered apoptosis that involves mitochondrial membrane potential depolarization and caspase activation.     

Biphasic Dose-Dependent G0/G1 and G2/M Cell-Cycle Arrest by Synthetic 2,3-Arylpyridylindole Derivatives in A549 Lung Cancer Cells

A collection of 2,3-arylpyridylindole derivatives were synthesized via the Larock heteroannulation and evaluated for their in vitro cytotoxic activity against A549 human lung cancer cells. Two derivatives expressed good cytotoxicity with IC₅₀ values of 1.18±0.25 μM and 0.87±0.10 μM and inhibited tubulin polymerization in vitro, with molecular docking studies suggesting the binding modes of the compounds in the colchicine binding site. Both derivatives have biphasic cell cycle arrest effects depending on their concentrations. At a lower concentration (0.5 μM), the two compounds induced G0/G1 cell cycle arrest by activating the JNK/p53/p21 pathway. At a higher concentration (2.0 μM), the two derivatives arrested the cell cycle at the G2/M phase via Akt signaling and inhibition of tubulin polymerization. Additional cytotoxic mechanisms of the two compounds involved the decreased expression of Bcl-2 and Mcl-1 antiapoptotic proteins through inhibition of the STAT3 and Akt signaling pathways.     

Synthesis, structure analysis, and antitumor evaluation of 3,6-dimethyl-1,2,4,5-tetrazine-1,4-dicarboxamide derivatives

3,6-Dimethyl-1,2,4,5-tetrazine-1,4-dicarboxamide derivatives were synthesized, and their structures were confirmed by single-crystal X-ray diffraction. This reaction yields the 1,4-dicarboxamide derivatives rather than the 1,2-dicarboxamide derivatives. Their in vitro antitumor activities were evaluated against SGC-7901, HO-8910, MCF-7, and A-549 cells. The results showed several compounds to be endowed with cytotoxicity in the low micromolar range. One compound (IC(50) =0.57 μM) was further evaluated in vivo against an A-549 xenograft in BALB/cA nude mice; it effected 76.4% inhibition of tumor weight through intraperitoneal (i.p.) administration of 40 mgkg(-1) body weight. Moreover, its acute toxicity was evaluated, and the i.p. LD(50) value was 325 mgkg(-1) in mice.     

Evaluation of Interactions of Selected Olivacine Derivatives with DNA and Topoisomerase II

Olivacine and ellipticine are model anticancer drugs acting as topoisomerase II inhibitors. Here, we present investigations performed on four olivacine derivatives in light of their antitumor activity. The aim of this study was to identify the best antitumor compound among the four tested olivacine derivatives. The study was performed using CCRF/CEM and MCF-7 cell lines. Comet assay, polarography, inhibition of topoisomerase II activity, histone acetylation, and molecular docking studies were performed. Each tested compound displayed interaction with DNA and topoisomerase II, but did not cause histone acetylation. Compound 2 (9-methoxy-5,6-dimethyl-1-({[1-hydroxy-2-(hydroxymethyl)butan-2-yl]amino}methyl)-6H-pyrido[4,3-b]carbazole) was found to be the best candidate as an anticancer drug because it had the highest affinity for topoisomerase II and caused the least genotoxic damage in cells.     

Novel 2-substituted quinolin-4-yl-benzenesulfonate derivatives: synthesis, antiproliferative activity, and inhibition of cellular tubulin polymerization

A series of 2‐substituted quinolin‐4‐yl‐benzenesulfonate derivatives were synthesized for the purpose of evaluating antiproliferative activity. Structure–activity relationships of the newly synthesized compounds against human lymphoblastic leukemia and various solid tumor cell growths in culture are discussed. Of these derivatives, 2‐phenyl‐6‐pyrrolidinyl‐4‐quinoline sulfonate analogues 10 f , 10 g , and 10 k , and 4′‐nitrophenyl sulfonate 10 m exhibit superior cytotoxicity over other sulfonates. The antiproliferative activities of these compounds correlate well with their abilities to induce mitotic arrest and apoptosis. Mechanistic studies indicate that they target the vinblastine binding site of tubulin and inhibit cellular tubulin polymerization. Hence, these compounds induce the formation of aberrant mitotic spindles and mitotic arrest, resulting in intensive apoptosis. The tested compounds were shown to be poor substrates for membrane multidrug resistance transporters. The present studies suggest that these newly synthesized compounds are promising tubulin polymerization inhibitors and are worthy of further investigation as antitumor agents.     

Overcoming tumor drug resistance with high-affinity taxanes: a SAR study of C2-modified 7-acyl-10-deacetyl cephalomannines

A series of C2-modified 10-deacetyl-7-propionyl cephalomannine derivatives was designed, prepared, and biologically evaluated. Some C2 meta-substituted benzoate analogues showed potent activity against both drug-sensitive and drug-resistant tumor cells in which resistance is mediated through either P-gp overexpression or beta-tubulin mutation mechanisms. The taxoid 15 b and related compounds are of particular interest, as they are much more cytotoxic than paclitaxel, especially against drug-resistant tumor cells; they are able to kill both drug-resistant and drug-sensitive cells (low R/S ratio), and they have high affinity for beta-tubulin. Our research results led to an important hypothesis, that is, a taxane with very high binding affinity for beta-tubulin is able to counteract drug resistance, which may assist in future taxane-based drug-discovery efforts.     

DNA interstrand cross-linking efficiency and cytotoxic activity of novel cadmium(II)-thiocarbodiazone complexes

We have prepared mono- and binuclear complexes of Zn(II) and Cd(II) with bis(2-pyridyl aldehyde) thiocarbodiazone (H(2)L(1)) and bis(methyl 3-pyridyl ketone) thiocarbodiazone (H(2)L(2)). Cytotoxicity data against the ovarian tumor cell line A2780cisR (acquired resistance to cisplatin) indicate that the mononuclear complex Cd/H(2)L(2) (1) and the binuclear complex Cd(2)/H(2)L(1) (4) are able to circumvent cisplatin resistance and that their cytotoxic activity does not substantially vary after depletion of intracellular levels of glutathione. Moreover, DNA binding studies show that complexes 1 and 4 have higher efficiency than cisplatin at forming DNA interstrand cross-links in both naked pBR322 plasmid and A2780cisR cellular DNA. Interestingly, the thiocarbodiazone ligands alone do not show the biological properties of complexes 1 and 4. Altogether these results suggest that DNA interstrand cross-link formation by compounds 1 and 4 might be related with their cytotoxic activity in cisplatin-resistant cells. We think that compounds 1 and 4 may represent a novel structural lead for the development of cadmium cytotoxic agents capable of improving antitumor activity in cisplatin-resistant tumors.     

Incorporation of Sulfonamide Moiety into Biguanide Scaffold Results in Apoptosis Induction and Cell Cycle Arrest in MCF-7 Breast Cancer Cells

Metformin, apart from its glucose-lowering properties, has also been found to demonstrate anti-cancer properties. Anti-cancer efficacy of metformin depends on its uptake in cancer cells, which is mediated by plasma membrane monoamine transporters (PMAT) and organic cation transporters (OCTs). This study presents an analysis of transporter mediated cellular uptake of ten sulfonamide-based derivatives of metformin in two breast cancer cell lines (MCF-7 and MDA-MB-231). Effects of these compounds on cancer cell growth inhibition were also determined. All examined sulfonamide-based analogues of metformin were characterized by greater cellular uptake in both MCF-7 and MDA-MB-231 cells, and stronger cytotoxic properties than those of metformin. Effective intracellular transport of the examined compounds in MCF-7 cells was accompanied by high cytotoxic activity. For instance, compound 2 with meta-methyl group in the benzene ring inhibited MCF-7 growth at micromolar range (IC₅₀ = 87.7 ± 1.18 µmol/L). Further studies showed that cytotoxicity of sulfonamide-based derivatives of metformin partially results from their ability to induce apoptosis in MCF-7 and MDA-MB-231 cells and arrest cell cycle in the G0/G1 phase. In addition, these compounds were found to inhibit cellular migration in wound healing assay. Importantly, the tested biguanides are more effective in MCF-7 cells at relatively lower concentrations than in MDA-MB-231 cells, which proves that the effectiveness of transporter-mediated accumulation in MCF-7 cells is related to biological effects, including MCF-7 cell growth inhibition, apoptosis induction and cell cycle arrest. In summary, this study supports the hypothesis that effective transporter-mediated cellular uptake of a chemical molecule determines its cytotoxic properties. These results warrant a further investigation of biguanides as putative anti-cancer agents.     

Synthesis of 9,9‐Dialkyl‐4,5‐diazafluorene Derivatives and Their Structure–Activity Relationships Toward Human Carcinoma Cell Lines

A homologous set of 9,9‐dialkyl‐4,5‐diazafluorene compounds were prepared by alkylation of 4,5‐diazafluorene with the appropriate alkyl bromide and under basic conditions. The structures of these simple organic compounds were confirmed by spectroscopic techniques (FTIR, NMR, and FABMS). Their biological effects toward a panel of human carcinoma cells, including Hep3B hepatocellular carcinoma, MDAMB‐231 breast carcinoma, and SKHep‐1 hepatoma cells, were investigated; a structure–activity correlation was established with respect to the length of the alkyl chain and the fluorene ring structure. The relationship between the mean potency [log(1/IC₅₀)] and alkyl chain length was systematically studied. The results show that compounds with butyl, hexyl, and octyl chains exhibit good growth inhibitory effects toward these three human carcinoma cell lines, and the 9,9‐dihexyl‐4,5‐diazafluorene further exhibits antitumor activity in athymic nude mice Hep3B xenograft models. For the structurally related dialkylfluorenes that lack the diaza functionality, in vitro cytotoxicity was not observed at clinically relevant concentrations.     

Growth Effects of Some Platinum(II) Complexes with Sulfur-Containing Carrier Ligands on MCF7 Human Breast Cancer Cell Line upon Simultaneous Administration with Taxol

The platinum (II)complexes, cis-[PtCl(2)(CH(3)SCH(2)CH(2)SCH(3))] (Pt1), cis-[PtCl(2)(dmso)(2)] (dmso is dimethylsulfoxide; Pt2) and cis-[PtCl(2)(NH(3))(2)] (cisplatin), and taxol (T) have been tested at different equimolar concentrations. Cells were exposed to complexes for 2 h and left to recover in fresh medium for 24, 48 or 72 h. Growth inhibition was measured by tetrazolium WST1 assay Analyses of the cell cycle, and apoptosis were performed by flow cytometry, at the same exposure times. The IC50 value of each platinum(II) complex as well as combination index (CI; platinum(II) complex + taxol) for various cytotoxicity levels were determined by median effects analysis.MCF7 cells were found to be sensitive to both Pt1 and Pt2 complexe These cisplatin analogues influenced the cell growth more effectively as compared to cisplatin. Cytotoxic effect was concentration and time-dependent. Profound growth inhibitory effect was observed for Pt1 complex, across all its concentrations at all recovery periods. A plateau effect was achieved three days after treatment at Pt1 concentrations 相似文献   

Antiparasitic Derivatives of the Furoquinoline Alkaloids Kokusaginine And Flindersiamine

We report the synthesis of 16 new compounds obtained from kokusaginine and flindersiamine, the main alkaloids isolated from the bark of Balfourodendron riedelianum. The activity of the compounds against axenic cultures of Trypanosoma cruzi epimastigtotes and trypomastigotes, as well as intracellular amastigotes, is described, together with their cytotoxic activity against three different human cell lines. The synthetic strategy for the preparation of the new compounds was based on the reactivity at the C4 position of the furoquinoline core towards nucleophiles. The new derivatives were synthesized by a Buchwald-Hartwig reaction, in most cases under green, solvent-free conditions. Compounds 1 c and 1 e displayed better in-vitro activity against trypomastigotes than benznidazole and nifurtimox (positive controls) with IC₅₀<4 μM. In addition, both compounds were not cytotoxic against the three human cell lines K562 (erytroleukimia), LM2 (breast cancer), and HaCat (keratinocyte). Interestingly, when evaluated against intracellular amastigotes, compound 1 c was able to significantly reduce the number of this parasite form, compared to the negative control.     

Synthesis and biological evaluation of pyrazolylnaphthoquinones as new potential antiprotozoal and cytotoxic agents

The importance of American trypanosomiasis (Chagas' disease) in human pathology is widely known. The prognosis of this disease is poor and the choice of effective medicines limited, thus study of new drugs is absolutely necessary. In this work, the activities of three new pyrazolylnaphthoquinones, heterocyclic naphthoquinones bearing 3-aminopyrazole rings, were evaluated on Trypanosoma cruzi, the etiological agent of Chagas' disease. These activities were compared with those of three 5-aminoisoxazole analogues. In addition, since these compounds belong to a family of antiprotozoal and cytotoxic/antitumor agents, the activities of all six against Plasmodium falciparum, Trypanosoma brucei rhodesiense, and murine L-6 cells were also investigated. In the biological tests, five of the compounds showed significant in vitro trypanocidal activities against T. cruzi, with activities similar to that of benznidazole. Two of the 5-aminoisoxazole analogues also showed good activities, in one case highly selective, against the K1 and NF54 strains of P. falciparum (IC(50)<0.12 microg mL(-1)). Three of the compounds were cytotoxic to murine L-6 cells (IC(50)=0.21-0.50 microg mL(-1)). The results suggested that the three pyrazolylnaphthoquinones and one of the 5-aminoisoxazole analogues could be starting points for lead optimization programs against T. cruzi and P. falciparum, respectively.