The effect of a novel dinuclear platinum complex with berenil and 2-picoline ligands on growth of human breast cancer cells

Evaluation of the cytotoxicity of a novel dinuclear platinum(II) complex of formula Pt2(2-picoline)4(berenil)2 employing a MTT assay and inhibition of [3H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that the complex was more potent anti-proliferative agent than cisplatin. Data from the ethidium displacement assay indicated that the complex showed specificity for AT base pairs of DNA. Our study showed that Pt2(2-picoline)4(berenil), was a potent catalytic inhibitor of topoisomerase II in opposition to cisplatin.     

DNA-binding activity and cytotoxicity of Pt-berenil compounds in MDA-MB-231 and MCF-7 breast cancer cells

The compounds of formula [Pt2Cl4(berenil)2]Cl4 and [Pt2Cl2(NH3)2(berenil)2]Cl4 were examined for cytotoxicity in breast cancer cell cultures and for inhibition of topoisomerases I and II. Evaluation of the cytotoxicity of these compounds employing a MTT assay and inhibition of [3H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that these compounds were more active than cisplatin. The DNA-binding ability of these compounds was evaluated by an ultrafiltration method using calf thymus DNA, poly(dA-dT)2 and poly(dG-dC)2, indicated that these compounds show strong specificity for AT base pairs. Binding studies indicate that these compounds bind more tightly to double-stranded DNA than cisplatin. The degree to which these compounds inhibited cell growth breast cancer cells was generally consistent with their relative DNA binding affinity. Mechanistic studies revealed that these compounds act as topoisomerase II (topo II) inhibitors in plasmid relaxation assays.     

Structure-activity studies of novel amidine analogues of chlorambucil: correlation of cytotoxic activity with DNA-binding affinity and topoisomerase II inhibition

A series of amidine analogues of chlorambucil (9-12), where 5-[4-(N-alkylamidino)phenyl]-2-furancarboxamide and the chlorambucil moiety are linked by a NH(CH(2))(2)NH chain, was synthesized and their cytotoxicity has been tested against the growth of human breast cancer MCF-7 cells. Evaluation of the cytotoxicity of compounds 9-12 employing a MTT assay and inhibition of [(3)H]thymidine incorporation into DNA demonstrated that these conjugates were more active than chlorambucil. Data from the ethidium displacement assay indicated that these compounds bind in the minor groove of DNA and show moderate specificity for AT base pairs. Compounds 9-12 were potent topoisomerase II inhibitors, with 50% inhibitory concentrations (IC(50))ranging from 10 to 40 microM. The cytotoxicity of the compounds 9-12 correlates with their DNA-binding affinities and their relative potency as topoisomerase II inhibitors. Altogether, these data suggest (i) that the cytotoxic activity of compounds 9-12 may be due to the combined effects of alkylation, DNA-minor groove binding, and (ii) that N-(2-aminoethyl)-5-(4-N-alkylamidinophenyl)-2-furancarboxamides (5-8) ligands are suitable linkers that favors DNA targeting by chlorambucil derivatives.     

Synthesis, DNA binding, topoisomerase inhibition and cytotoxic properties of 2-chloroethylnitrosourea derivatives of hoechst 33258

A number of novel 2-chloroethylnitrosourea derivatives of Hoechst 33258 were synthesized and examined for cytotoxicity in breast cancer cell cultures and for inhibition of topoisomerases I and II. Evaluation of the cytotoxicity of these compounds employing a MTT assay and inhibition of [3H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that these compounds were more active than Hoechst 33258. The DNA-binding ability of these compounds was evaluated by an ultrafiltration method using calf thymus DNA, poly(dA-dT)2 and poly(dG-dC)2, indicated that these compounds as well as Hoechst 33258 well interact with AT base pair compared with GC pair. Binding studies indicate that these compounds bind more tightly to double-stranded DNA than the parent compound Hoechst 33258. The degree to which these compounds inhibited cell growth breast cancer cells was generally consistent with their relative DNA binding affinity. Mechanistic studies revealed that these compounds act as topoisomerase I (topo I) or topoisomerase II (topo II) inhibitors in plasmid relaxation assays.     

Synthesis and biological evaluation of new cyclic amidine analogs of chlorambucil

A number of novel cyclic amidine analogs of chlorambucil were synthesized and examined for cytotoxicity in breast cancer cell cultures and for inhibition of topoisomerases I and II. Evaluation of the cytotoxicity of these compounds employing a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and inhibition of [(3)H]-thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that these compounds were more active than chlorambucil. The degree to which these compounds inhibited cell growth breast cancer cells was directly correlated to DNA-binding affinity. These studies indicate that cyclic amidine analogs of chlorambucil are a potent catalytic inhibitor of topoisomerase II but not topoisomerase I. The highest degree of DNA binding and cytotoxicity in both MDA-MB-231 and MCF-7 breast cancer cells was observed for the compound, which possess a 4,5-dihydro-1H-imidazol moiety.     

Antiproliferative activity of derivatives of ouabain, digoxin and proscillaridin A in human MCF-7 and MDA-MB-231 breast cancer cells

Three derivatives of ouabain, digoxin and proscillaridin A containing the carboxylic group instead of the lactone moiety were synthesized and examined for cytotoxicity in human breast cancer cells. Evaluation of the cytotoxicity of these compounds employing an MTT assay and inhibition of [3H]thymidine incorporation into DNA in both MCF-7 and MDA-MB-231 breast cancer cells demonstrated that compound 3, the most active of the series, proved to be only slightly less potent than proscillaridin A. We evaluated the effects of these compounds 1-3 on change in intracellular Ca2+, appearance of apoptosis, inhibition of DNA topoisomerase I and II, and the activity of caspase-3 in breast cancer cells. These studies indicate that the increase in potency for 3 may be related, in part, to an activation of caspase-3, increasing free calcium concentration and topoisomerase II inhibition. All these data emphasize the potential usefulness of these derivatives of cardiac glycosides as anticancer agents.     

新型6,7-二甲氧基-4-(2-氟苯氧基)喹啉类c-Met抑制剂的设计、合成及生物活性研究

基于卡博替尼(cabozantinib)和foretinib的化学结构,通过改变中间链,设计合成了一系列含有哌嗪酰胺的6,7-二甲氧基-4-(2-氟苯氧基)喹啉类c-Met抑制剂。这些化合物未见文献报道,其结构通过MS和NMR确证。采用酶联免疫吸附测定(ELISA)法和MTT法测定了目标化合物对c-Met的抑制活性和对人结肠癌细胞(HT-29)、人肺癌细胞(H460)、人非小细胞肺癌细胞(A549)和人胃癌细胞(MKN-45)的细胞毒性。结果表明,4-(4-氯苯基)-N-[4-[(6,7-二甲氧基-4-喹啉)氧基]-3-氟苯基]哌嗪-1-甲酰胺(1b)、4-(3-氯苯基)-N-[4-[(6,7-二甲氧基-4-喹啉)氧基]-3-氟苯基]哌嗪-1-甲酰胺(1h)和4-(2-氯苯基)-N-[4-[(6,7-二甲氧基-4-喹啉)氧基]-3-氟苯基]哌嗪-1-甲酰胺(1j)对HT-29、H460、A549和MKN-45细胞的抑制活性明显优于对照药卡博替尼。其中,化合物1h和1j对c-Met具有较强的抑制活性,其IC50值分别为0.007 2和0.009 8 μmol/L。     

Synthesis and Cytotoxic Activity of Novel Amidine Analogues of Bis(2‐chloroethyl)amine

Novel nitrogen mustard agents 7 – 12 involving 4‐(N,N‐bis(2‐chloroethyl)aminophenyl)propylamine linked to a 5‐(4‐N‐alkylamidinophenyl)‐2‐furancarboxylic acid moiety by the formation of an amide bond have been synthesized, characterized, and evaluated for their in‐vitro cytotoxic activity against MDA‐MB‐231 and MCF‐7 human breast cancer cells. Evaluation of the cytotoxicity of 7 – 12 employing a MTT assay and inhibition of [³H]thymidine incorporation into DNA demonstrated that these compounds exhibit remarkable cytotoxic effects in comparison with 4‐[bis(2‐chloroethyl)amino]benzenebutanoic acid. Compounds 7 and 9 , which possess a cationic amidine and 4,5‐dihydro‐1H‐imidazol function moiety are approximately ten times more potent than 4‐[bis(2‐chloroethyl)amino]benzenebutanoic acid. The new compounds were evaluated as DNA topoisomerase II inhibitors. The cytotoxicity of the compounds 7 – 12 correlates with their DNA‐binding affinities and their relative potency as topoisomerase II inhibitors.     

Proline-linked nitrosoureas as prolidase-convertible prodrugs in human breast cancer cells

A number of novel proline-linked nitrosoureas (1-4) were synthesized and examined for cytotoxicity and influence on DNA and collagen biosynthesis in MDA-MB-231 and MCF-7 human breast cancer cells. Evaluation of the cytotoxicity of these compounds employing a MTT assay and inhibition of [(3)H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that compound 2, the most active of the series, proved to be only slightly less potent than carmustine. It has also been found that carmustine did not inhibit MCF&-7 cells prolidase activity, while compounds 1-4 significantly increased its activity, when used at 50-250 muM concentrations. Proline-linked nitrosoureas (1-4) also had lower ability to inhibit collagen biosynthesis in MCF-7 cells, compared to carmustine. The expression of beta(1)-integrin receptor and phosphorylated MAPK, ERK(1) and ERK(2) was significantly decreased in MCF-7 cells incubated for 24 h with 60 muM of compounds 2 and 4 compared to the control, untreated cells, whereas under the same conditions carmustine did not evoke any changes in expression of all these signaling proteins, as shown by Western immunoblot analysis. These results indicate the proline-linked nitrosoureas (1-4), represent multifunctional inhibitors of breast cancer cell growth and metabolism.     

Cytotoxicity and induction of apoptosis of human breast cancer cells by novel platinum(II) complexes

The current work investigates the influence of novel dinuclear platinum(II) compounds of structure: Pt₂(3-ethylpyridine)₄(berenil)₂ (Pt10) and Pt₂(3-butylpyridine)₄(berenil)₂ (Pt11) on growth and viability of MDA-MB-231 and MCF-7 breast cancer cells as well as their putative mechanism of cytotoxicity. Evaluation of the cytotoxicity of Pt10 and Pt11 employing a MTT assay and inhibition of [³H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that these compounds were more potent antiproliferative agents than cisplatin. In our study the induction of apoptosis by Pt10 and Pt11 in human breast cancer cells was confirmed by several biochemical markers, such as: phosphatidylserine externalization, loss of mitochondrial membrane potential ΔΨ_m, caspase-3, -8, -9 activity, and DNA degradation. Pt10 and Pt11 induce apoptosis of breast cancer cells via mechanisms dependent on caspases activation and associated with mitochondrial membrane potential disruption.     

Amidine analogues of melphalan: synthesis, cytotoxic activity, and DNA binding properties

Design, synthesis, and cytotoxic activity of amidine derivatives of melphalan are described and structure-activity relationships are discussed. Evaluation of the cytotoxicity of these compounds employing a MTT assay and inhibition of [(3)H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 human breast cancer cells demonstrated that these compounds were more active than melphalan. Data from the ethidium displacement assay showed that these compounds were able to bind in the minor groove-binding mode in AT sequences of DNA. The cytotoxic properties of the amidine analogues of melphalan towards cultured human breast cancer cells correlate with topoisomerase II inhibitory properties but not with DNA-binding properties.     

Cytotoxic efficacy of a novel dinuclear platinum(II) complex in human breast cancer cells

Evaluation of the cytotoxicity of a novel dinuclear platinum(II) complex of formula Pt₂(2-picoline)₄(berenil)₂ employing a MTT assay and inhibition of [³H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that the complex was more of a potent antiproliferative agent than cisplatin. The DNA-binding ability of Pt₂(2-picoline)₄(berenil)₂ estimated by an ethidium displacement assay indicated that the complex showed strong specificity for AT base pairs in the minor groove of DNA. Our study showed that Pt₂(2-picoline)₄(berenil)₂ was a potent catalytic inhibitor of topoisomerase II in opposition to cisplatin. Pt₂(2-picoline)₄(berenil)₂ was found to be a more active inhibitor of collagen biosynthesis than cisplatin. The up regulation of β₁-integrin and insulin-like growth factor I (IGF-I) receptor expression by the complex was shown to be accompanied by an increase in the expression of mitogen activated protein kinases in breast cell lines. The phenomenon was related to the increased expression of nuclear factor-kappaB (ΝF-κΒ) by Pt₂(2-picoline)₄(berenil)₂ as shown by the Western immunoblot analysis. Flow cytometric analysis and a fluorescent microscopy assay demonstrated that cell death appeared to result from apoptosis, with the possibility of secondary necrosis. The data presented suggested that Pt₂(2-picoline)₄(berenil)₂ impaired growth and metabolism of breast cancer cells more efficiently than cisplatin. These results indicated also the different properties of Pt₂(2-picoline)₄(berenil)₂ and cisplatin.     

1, 2-Bis(2, 6-difluoro-3-hydroxyphenyl)ethylene-diamine]platinum(II) complexes, compounds for the endocrine therapy of breast cancer - mode of action II: contribution of drug inactivation, cellular drug uptake and sterical factors in the drug-target interaction to the antitumor activity

The marked activity of [meso-1, 2-bis(2, 6-difluoro-3-hydroxyphenyl)ethylenediamine]platinum(II) (meso-3-PtLL', L, L' = Cl(2) or L = OH(2), L' = OSO(3)) on the hormone-sensitive MXT-M-3, 2 breast cancer implanted in mice is most probably due to a mechanism based on the reduction of the endogenous estrogen level. Cytotoxic effects which are poorly pronounced in experiments on several breast cancer cell lines (e.g. MCF-7), do not significantly contribute to the anti-breast cancer activity of this compound. In contrast to this, the standard cisplatin and the structurally related comparison compound [meso-1, 2-bis(4-fluorophenyl)ethylenediamine]platinum(II) (meso-4-PtLL', L, L' = Cl(2) or L = OH(2), L' = OSO(3)) are strongly active in vivo as well as in vitro. Both effects entail programmed cell death, which is responsible for the inhibition of the tumor growth. The minor cytotoxicity of meso-3-PtLL' in breast cancer cell cultures is caused neither by an inappropriate rate of reaction with bionucleophiles (e.g. by a too fast inactivation by plasma proteins) nor solely by the observed poor absorption by the tumor cells resulting in an insufficient drug concentration at the DNA. Additionally, an impeded reaction with biologically important, guanine-rich sequences of DNA (owing to the 2, 6-standing F atoms which hinder the drug-target inter action) must be assumed as cause of its marginal cytotoxicity.     

3-methyl-2-(4-substituted phenyl)-4,5-dihydronaphtho[1,2-c]-pyrazoles: synthesis and in-vitro biological evaluation as antitumour agents

The synthetic strategies and characterization of some novel derivatives of 3-methyl-2-(4-substituted phenyl)-4,5-dihydronaphtho[1,2-c]pyrazoles carrying different pharmacophores and heterocyclic rings that are relevant to potential antitumour and cytotoxic activities are described. The antitumour activities of the newly synthesized compounds were evaluated according to the protocol of the National Cancer Institute (NCI) in-vitro disease-oriented human cells screening panel assay. The results revealed that six compounds, namely 6, 8, 11, 15, 17 and 18; displayed promising in-vitro antitumour activity in the 60-cell lines assay. The sulfonylthioureido group emerged as the most favourable pharmacophore. Incorporating such thioureido counterpart into the 6-membered 1,3-thiazinan-5-one resulted in better antitumour activities than those displayed by the 5-membered thiazoles and the 6-membered 1,3-thiazinan-4-one ring systems. Further ring expansion led to a total loss of the antitumour activity. The analog 18, 3-benzyl-2-[4-(3-methyl-4,5-dihydronaphtho-[1,2-c]pyrazol-2-yl)-benzenesulfonylimino]-1,3-thiazinan-5-one, proved to be the most active member identified in this series of compounds (GI(50), TGI, and LC(50) MG-MID values of 34.7, 85.1 and 97.7 microM, respectively). The differential cytotoxicity of the six active compounds to cancer and normal cells was studied utilizing the standard MTT cell viability assay. Compounds 17 and 18 were totally selective for the breast cancer cell line MCF7 (IC(50 )8.5 and 4.7 microM), without exerting any inhibitory effect on the normal breast cell line MCF-10A at the concentration level used (25 microM).     

Dinuclear alkyldiamine platinum antitumor compounds: a structure-activity relationship study

Six related dinuclear trans-platinum complexes, with the formula [[trans-PtCl(2)(NH(3))(L)](2)(mu-H(2)N(CH(2))(n)NH(2))](2+) (L = pyridine, 2-picoline, 4-picoline; n = 4, 6) and chloride or nitrate anions, are compared with known cytotoxic dinuclear compounds (L = NH(3); n = 4, 6) that overcome cisplatin resistance. The cytotoxicity of the compounds was determined in L1210 murine leukemia and L1210/2, a cisplatin-resistant derivative. Unlike the L = NH(3) compounds, the substituted n = 4 compounds are more susceptible toward the resistance mechanisms in L1201/2. The n = 6 compounds, however, have comparable IC(50) values in both cell lines. In general, the substituted compounds are less cytotoxic than their NH(3) counterparts. After incubation with equimolar concentrations, the amount of platinum bound to cellular DNA was determined. The compounds show comparable binding, except for the sterically hindered 2-picoline compounds that bind significantly less. The amounts of platinum bound to DNA do not correlate with the cytotoxicity data. As DNA is considered to be the cellular target of platinum antitumor drugs, structural details of the DNA adducts probably account for the differences in cytotoxic activity.     

Aromatic extended bisamidines: synthesis, inhibition of topoisomerases, and anticancer cytotoxicity in vitro

A series of four aromatic extended bisamidines (12-15) differing in the nature of their terminal basic side chains were synthesized and evaluated for cytotoxic activity in MCF-7 cultured breast cancer cells. The concentrations of 12, 13, 14, and 15 needed to inhibit [3H]thymidine incorporation into DNA by 50% (IC50) were found to be 63 microM, 85 microM, 77 microM, and 97 microM, respectively. To test whether cytotoxic properties were related to DNA-binding and topoisomerase action, the bisamidines 12-15 were evaluated in a cell-free system. Data from the ethidium displacement assay showed that bisamidines 12-15 have significant affinity for DNA and show moderate specificity for AT base pairs. In the topoisomerase II assay, the relaxation of DNA was inhibited with all four drugs and the extent of inhibition was directly proportional to the drug concentration. This suggests that DNA binding may be implicated in the cytotoxicity of these bisamidines, possibly by inhibiting interactions between topoisomerase II and their DNA targets.     

Synthesis and cytotoxicity of bis-1,3,4-oxadiazoles and bis-pyrazoles derived from 1,4-bis[5-thio-4-substituted-1,2,4-triazol-3-yl]-butane and their DNA binding studies

A new series of 1,4-bis[5-(5-mercapto-1,3,4-oxadiazol-2-yl-methyl)-thio-4-substituted-1,2,4-triazol-3-yl]-butane 7-12 and 1,4-bis[5-(1-oxo-1-(3,5 dimethyl pyrazol-1-yl)-methyl)-thio-4-substitued-1,2,4-triazol-3-yl]-butane 13-18 were prepared from 1,4-bis(5[hydrazinocarbonylmethylthio]-4-substituted-1,2,4-triazol-3-yl) butane based derivativess were synthesized 1-6. All the synthesized compounds were characterized by IR, NMR and Mass spectral studies. The synthesized compounds 7-18 were screened for in-vitro cytotoxicity potential using the standard MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay against a panel of three human cancer cell lines: Lung carcinoma A-549, colon carcinoma HT-29 and breast cancer MDA MB-231. DNA binding studies were conducted for three potent molecules by absorption titration method.     

Mono- and polynuclear [alkylamine]platinum(II) complexes of [1,2-bis(4-fluorophenyl)ethylenediamine]platinum(II): synthesis and investigations on cytotoxicity, cellular distribution, and DNA and protein binding

A series of mononuclear and dinuclear alkylamine derivatives of [meso-1,2-bis(4-fluorophenyl)ethylenediamine]platinum(II) (m-4F-PtL-R1 and (m-4F-PtL)2-R2; R(1) = alkylamine, R(2) = alkyldiamine, L = DMSO or Cl) as well as the DAB(PA)(4) polyimine dendrimer complex ((m-4F-PtDMSO)4DAB(PA)4; DAB(PA)4 = N,N,N',N'-tetrakis(3-aminopropyl)butane-1,4-diamine) were synthesized and tested for cytotoxicity, intracellular distribution, and DNA and protein binding. All compounds strongly bound to human serum albumin by hydrophobic and electrostatic interactions. These inactivation reactions hindered the uptake into tumor cells and prevented strong cytotoxic effects. If serum-free medium was used, a high accumulation grade in MCF-7 breast cancer cells and a high DNA binding was observed. As most efficient compound (m-4F-PtDMSO)4DAB(PA)4 was identified. It showed a 20-fold higher cellular uptake and an approximately 700-fold higher DNA binding than cisplatin.     

丹酚酸A抑制核苷转运并增强化疗药物的抗肿瘤作用丹酚酸A抑制核苷转运并增强化疗药物的抗肿瘤作用

目的观察丹酚酸A(SAA)的抑制核苷转运活性及其抗肿瘤作用。方法用3H-TdR和3H-UR转运测定法,克隆生成测定法以及小鼠移植性肉瘤180模型。结果SAA抑制艾氏腹水癌细胞的胸苷和尿苷的转运,其IC₅₀分别为18.1和17.1 μmol·L^-1。SAA能明显增强5-FU、丝裂霉素C、MTX对KB细胞、肝癌BEL-7402细胞的细胞毒性。体内试验,SAA 200 mg·kg^-1和5-FU 10 mg·kg^-1单独使用的抑瘤率分别为41%和27%;SAA和5-FU联合使用的抑瘤率为63%(CDI=0.86)。结论SAA有抑制肿瘤细胞核苷转运的活性,可增强5-氟尿嘧啶等药物的抗肿瘤作用,有可能用于肿瘤联合化疗。