A series of unconjugated ferrocenyl phenols: prospects as anticancer agents

We recently reported that a ferrocenyl diphenol butene derivative showed a very strong cytotoxic effect on both hormone-dependent and -independent breast cancer cell lines. In order to obtain more information about the structure-activity relationship in the cytotoxicity of small ferrocene compounds, we have prepared a series of simple unconjugated ferrocenyl diphenol complexes (ortho,para; meta,para; para,para). These compounds retain a reasonable to good affinity for both estrogen receptor types, with higher values for the beta form, and superior binding for the para,para diphenol complex (RBA=28%). In vitro these complexes exhibit significant cytotoxic effects on hormone-independent prostate (PC3) and breast cancer cell lines (MDA-MB231), with IC50 values between 2.5 and 4.1 microM. This effect is more marked with PC3, the ortho,para diphenol complex proving the most effective. On the hormone-dependent MCF7 breast cancer cell line, the observed effect seems to be the result of two components, one cytotoxic (antiproliferative), the other estrogenic (proliferative). Electrochemical studies show that the cytotoxic effect of the complexes correlates with the ease of oxidation of the ferrocene group. All these complexes are much less cytotoxic than the ferrocenyl diphenol butene derivative.     

Cellular uptake, cytotoxicity, and metabolic profiling of human cancer cells treated with ruthenium(II) polypyridyl complexes [Ru(bpy)2(N--N)]Cl2 with N--N=bpy, phen, dpq, dppz, and dppn

A series of five ruthenium(II) polypyridyl complexes [Ru(bpy)2(N--N)]Cl2 was tested against human HT-29 and MCF-7 cancer cell lines. Cellular uptake efficiency and cytotoxicity were found to increase with the size of the aromatic surface area of the N--N ligand. The most active compound carrying the dppn ligand exhibits a low micromolar IC(50) value against both cell lines comparable to that of cisplatin under similar conditions. Continuous measurement of oxygen consumption, extracellular acidification rate, and impedance of the cell layer with a chip-based sensor system upon exposure to the complexes showed only small changes for the first two parameters throughout the series. A significant and irreversible decrease in impedance was, however, found for the dppn compound. This suggests that its biological activity is related to modifications in cell morphology or cell-cell and cell-matrix contacts.     

Kinetic Studies of Newly Patented Aminoalkanol Derivatives with Potential Anticancer Activity as Competitive Inhibitors of Prostate Acid Phosphatase

Background: Acid phosphatase and its regulation are important objects of biological and clinical research and play an important role in the development and treatment of prostate and bone diseases. The newly patented aminoalkanol (4-[2-hydroxy-3-(propan-2-ylamino)propyl]-1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5,10-trione hydrochloride) (I) and (4-[3-(dimethylamino)-2-hydroxypropyl]-1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5,10-trione hydrochloride) (II) derivatives have potential anticancer activity, and their influence on enzymatic activity can significantly impact the therapeutic effects of acid phosphatase against many diseases. Therefore, in this study, we investigated the action of compounds (I) and (II) on acid phosphatase. Methods: Capillary electrophoresis was used to evaluate the inhibition of acid phosphatase. Lineweaver–Burk plots were constructed to compare the Km of this enzyme in the presence of inhibitors (I) or (II) with the Km in solutions without these inhibitors. Results: Compound (I) showed a stronger competitive inhibition against acid phosphatase, whereas derivative (II) showed a weaker competitive type of inhibition. The detailed kinetic studies of these compounds showed that their type and strength of inhibition as well as affinity depend on the kind of substituent occurring in the main chemical molecule. Conclusions: This study is of great importance because the disclosed inhibition of acid phosphatase by compounds (I) and (II) raises the question of whether these compounds could have any effect on the treatment possibilities of prostate diseases.     

超高效液相色谱-串联质谱法测定化妆品中38种抗感染药

建立了同时测定2种不同基质类型化妆品中非法添加38种抗感染禁用药的超高效液相色谱-串联质谱方法。样品经溶剂提取后,采用Waters Acquity BEH C;(50 mm×2.1 mm,1.7μm)色谱柱,流动相A为0.1%乙酸铵缓冲液(pH=4.0),流动相B为0.1%甲酸甲醇,梯度洗脱;使用三重四极杆质谱多反应监测模式(MRM)检测,以保留时间和相对离子丰度定性,外标法定量。结果表明,氯霉素在质量浓度100~1 000μg/L范围内,其余37种抗感染药在质量浓度15~150μg/L范围内均呈现良好的线性关系,相关系数均大于0.99;方法检出限和定量限分别为0.3~240.4μg/kg和1.1~801.2μg/kg。3个不同浓度加标水平下,38种抗感染化合物的加标回收率为79.0%~119.8%,相对标准偏差为0.3%~9.7%(n=6)。该方法准确、灵敏、快速,适用于水剂和膏霜化妆品中38种抗感染药的同时测定。     

Synthesis and cytotoxicity of enantiomerically pure [1,2-diamino-1-(4-fluorophenyl)-3-methylbutane]platinum(II) complexes

A series of leaving group derivatives of enantiomerically pure [1,2-diamino-1-(4-fluorophenyl)-3-methylbutane]platinum(II) complexes were synthesized and tested for cytotoxicity. The enantiomeric purity was determined by 1H NMR spectroscopy on the final diamines after derivation with (1R)-myrtenal. For coordination to platinum, the diamines were reacted with K2PtI4. The treatment of diiodoplatinum(II) complexes (4F-Ph/iProp-PtI2) with Ag2SO4 resulted in the sulfatoplatinum(II) complexes (4F-Ph/iProp-PtSO4), which can be easily transformed to dichloroplatinum(II) complexes (4F-Ph/iProp-PtCl2) with 2 n HCl. The importance of the leaving groups and the configuration at the diamine ligand on the antiproliferative effects was evaluated on the hormone-dependent MCF-7 and the hormone-independent MDA-MB 231 breast cancer cell lines as well as the LNCaP/FGC prostate cancer cell line. (R,R)-4F-Ph/iProp-PtCl2 was identified as the most active platinum(II) complex. The 3-methyl group increased antiproliferative effects relative to the [1,2-diamino-1-(4-fluorophenyl)butane]platinum(II) complexes described in an earlier study.     

Sorption of ruthenium by dipropylmethyl-2-(N,N-diisobutyl) acetamidoammonium iodide impregnated Amberlite XAD-4 resin from nitric acid medium

Dipropylmethyl-2-(N,N-diisobutyl)acetamidoammonium iodide has been impregnated on Amberlite XAD-4 resin and investigated for sorption of Ru from nitric acid medium. Equilibrium sorption data for Ru uptake were represented well by the Langmuir isotherm equation (R² = 0.98) compared to Freundlich isotherm equation (R² = 0.86). The maximum monolayer coverage (Q₀) value of 6.25 mg/g as obtained from Langmuir isotherm was close to the experimental value (5.63 mg/g). The heterogeneity parameter (1/n) = 0.37 obtained from the slope of Freundlich isotherm indicates slight heterogeneity in sorption process. Aqueous solutions of 5% ammonia or 10% sodium hydroxide were found suitable for desorption. The method can be applied for separation of Ru from acidic waste solutions.     

Design and synthesis of conformationally constrained cyclophilin inhibitors showing a cyclosporin-A phenotype in C. elegans

Cyclophilin A (CypA) is a member of the immunophilin family of proteins and receptor for the immunosuppressant drug cyclosporin A (CsA). Here we describe the design and synthesis of a new class of small-molecule inhibitors for CypA that are based upon a dimedone template. Electrospray mass spectrometry is utilised as an initial screen to quantify the protein affinity of the ligands. Active inhibitors and fluorescently labelled derivatives are then used as chemical probes for investigating the biological role of cyclophilins in the nematode Caenorhabditis elegans.     

Identifying and characterizing binding sites on the irreversible inhibition of human glutathione S-transferase P1-1 by S-thiocarbamoylation

Human glutathione S-transferase P1-1 (hGST P1-1) is involved in cell detoxification processes through the conjugation of its natural substrate, reduced glutathione (GSH), with xenobiotics. GSTs are known to be overexpressed in tumors, and naturally occurring isothiocyanates, such as benzyl isothiocyanate (BITC), are effective cancer chemopreventive compounds. To identify and characterize the potential inhibitory mechanisms of GST P1-1 induced by isothiocyanate conjugates, we studied the binding of GST P1-1 and some cysteine mutants to the BITC-SG conjugate as well as to the synthetic S-(N-benzylcarbamoylmethyl)glutathione conjugate (BC-SG). We report here the inactivation of GST P1-1 through the covalent modification of two Cys47 residues per dimer and one Cys101. The evidence has been compiled by isothermal titration calorimetry (ITC) and electrospray ionization mass spectrometry (ESI-MS). ITC experiments suggest that the BITC-SG conjugate generates adducts with Cys47 and Cys101 at physiological temperatures through a corresponding kinetic process, in which the BITC moiety is covalently bound to these enzyme cysteines through an S-thiocarbamoylation reaction. ESI-MS analysis of the BITC-SG incubated enzymes indicates that although the Cys47 in each subunit is covalently attached to the BITC ligand moiety, only one of the Cys101 residues in the dimer is so attached. A plausible mechanism is given for the emergence of inactivation through the kinetic processes with both cysteines. Likewise, our molecular docking simulations suggest that steric hindrance is the reason why only one Cys101 per dimer is covalently modified by BITC-SG. No covalent inactivation of GST P1-1 with the BC-SG inhibitor has been observed. The affinities and inhibitory potencies for both conjugates are high and very similar, but slightly lower for BC-SG. Thus, we conclude that the presence of the sulfur atom from the isothiocyanate moiety in BITC-SG is crucial for its irreversible inhibition of GST P1-1.     

13-cis-维A酸-5-氟尿嘧啶酯的合成、表征及其活性研究

在比较DCC-DMAP和HMPA两种不同合成方法的基础上,在室温下顺利地将在通常反应条件下极易异构化的13-cis-维A酸合成了其衍生物13-cis-维A酸-N1-(2-四氢呋喃烷基)-N3-乙基-5-氟尿嘧啶酯(5,RAFU),其结构通过1HNMR、13CNMR和MS进行了表征。生物活性测试表明,该化合物对肝癌细胞、舌癌细胞等癌细胞都具有抗癌活性。     

The potential of P1 site alterations in peptidomimetic protease inhibitors as suggested by virtual screening and explored by the use of C-C-coupling reagents

A synthetic concept is presented that allows the construction of peptide isostere libraries through polymer-supported C-acylation reactions. A phosphorane linker reagent is used as a carbanion equivalent; by employing MSNT as a coupling reagent, the C-acylation can be conducted without racemization. Diastereoselective reduction was effected with L-selectride. The reagent linker allows the preparation of a norstatine library with full variation of the isosteric positions including the P1 side chain that addresses the protease S1 pocket. Therefore, the concept was employed to investigate the P1 site specificity of peptide isostere inhibitors systematically. The S1 pocket of several aspartic proteases including plasmepsin II and cathepsin D was modeled and docked with approximately 500 amino acid side chains. Inspired by this virtual screen, a P1 site mutation library was designed, synthesized, and screened against three aspartic proteases (plasmepsin II, HIV protease, and cathepsin D). The potency of norstatine inhibitors was found to depend strongly on the P1 substituent. Large, hydrophobic residues such as biphenyl, 4-bromophenyl, and 4-nitrophenyl enhanced the inhibitory activity (IC50) by up to 70-fold against plasmepsin II. In addition, P1 variation introduced significant selectivity, as up to 9-fold greater activity was found against plasmepsin II relative to human cathepsin D. The active P1 site residues did not fit into the crystal structure; however, molecular dynamics simulation suggested a possible alternative binding mode.     

Generation and Screening of Oxime Libraries Addressing the Neuronal GABA Transporter GAT1

The objective of the present study was to transfer the concept of library screening by MS binding assays, so far applied to pseudostatic hydrazine libraries, to static oxime libraries to screen for new potent inhibitors of mGAT1, the most abundant GABA transporter in the central nervous system that represents a validated drug target for the treatment of epilepsy. Library generation was performed by reaction of guvacine derivatives possessing a hydroxylamine functionality with various sets of four aldehydes. After dilution, the libraries were screened by competitive MS binding assays. Deconvolution experiments allowed hits in the most active libraries to be identified, and they were resynthesized for biological evaluation. That way a series of compounds was identified that displayed binding affinities ≥8.00 (pK_i) at mGAT1, one of which was found to be the most potent mGAT1 inhibitor known to date in a functional GABA uptake assay with a pIC₅₀ value of 8.27±0.03.     

Design, synthesis, and biological evaluation of aminoboronic acids as growth-factor receptor inhibitors of EGFR and VEGFR-1 tyrosine kinases

A series of aminoboronic acids was synthesized based on the structure of lavendustin pharmacophore 1. Their inhibitory activities against the epidermal growth-factor receptor (EGFR) and vascular endothelial growth-factor receptor-1 (VEGFR-1, Flt-1) protein tyrosine kinases, and various protein kinases, PKA, PKC, PTK, and eEF2K were evaluated. Selective inhibition activities were observed in a series of aminoboronic acids. 4-Methoxy-3-((2- methoxyphenylamino)methyl)phenylboronic acid 10 inhibited EGFR tyrosine kinase, whereas 4-(2,5-dihydroxybenzylamino)phenylboronic acid 12 inhibited Flt-1 protein kinase, although lavendustin pharmacophore 1 inhibited both EGFR and Flt-1 kinases at a compound concentration of 1.0 microg mL(-1). The selective inhibition of EGFR by 10 is considered to be due to the substitution of the dihydroxy groups on the benzyl moiety for a boronic acid group at the para position, whereas the selective inhibition of Flt-1 by 12 is due to the substitution of the carboxyl group on the aniline moiety in the lavendustin pharmacophore 1 for a boronic acid group.     

Design, synthesis, biological evaluation, and molecular modeling studies of TIBO-like cyclic sulfones as non-nucleoside HIV-1 reverse transcriptase inhibitors

TIBO- and TBO-like sulfone derivatives 1 and 2 were designed, synthesized, and tested for their ability to block the replication cycle of HIV-1 in infected cells. The anti-HIV-1 activities of sulfones 3, which were intermediates in the syntheses of 1 and 2, were also evaluated. Surprisingly, the sulfone analogues of TIBO R82913 (compounds 1) were inactive, whereas interesting results were obtained for truncated derivatives 2. Compound 2 w was the most potent among this series in cell-based assays (EC50=0.07 microM, CC50>200 microM, SI>2857). It was twofold less potent than R82913, but more selective. An X-ray crystallographic analysis was carried out to establish the absolute configuration of 2 w and its enantiomer 2 x, which were obtained by semipreparative HPLC of 2 v, one of the most potent racemates. Compounds 1-3 were proven to target HIV-1 RT. In fact, representative derivatives inhibited recombinant HIV-1 RT in vitro at concentrations similar to those active in cell-based assays. 3D QSAR studies and docking simulations were developed on TIBO- and TBO-like sulfone derivatives to rationalize their anti-HIV-1 potencies and to predict the activity of novel untested sulfone derivatives. Predictive 3D QSAR models were obtained with a receptor-based alignment by docking of TIBO- and TBO-like derivatives into the NNBS of RT.     

Gamma-Radiolytic Stability of Solvents Containing C5-BPP (2,6-Bis(5-(2,2-dimethylpropyl)-1H-pyrazol-3-yl)pyridine) for Actinide(III)/Lanthanide(III) Separation

The stability of solvents containing the C5-BPP (2,6-Bis(5-(2,2-dimethylpropyl)-1H-pyrazol-3-yl)pyridine) extractant against gamma-irradiation up to 330 kGy adsorbed dose was evaluated using HPLC mass spectrometric and solvent extraction methods. The main radiolysis products were identified using high-resolution mass spectrometry. Quantitative analysis of the residual C5-BPP concentration in irradiated samples was accomplished by a specifically developed MRM (Multiple Reaction Monitoring) method. A mixture of C5-BPP with 2-bromohexanoic acid in kerosene and 1-octanol, which had been used in an actinide(III)/lanthanide(III) separation process demonstration test, was also studied for its radiolytic stability and a remarkable protective effect of the presence of nitric acid during irradiation was found.     

MS-binding assays: kinetic, saturation, and competitive experiments based on quantitation of bound marker as exemplified by the GABA transporter mGAT1

A new kind of binding assay is described in which the amount of a nonlabeled marker bound to the target is quantified by LC-ESI-MS-MS. This new approach was successfully implemented with nonlabeled NO 711 as marker and the GABA transporter subtype mGAT1 as target. The native marker bound to the target was liberated from the receptor protein by methanol denaturation after filtration. A reliable and sensitive LC-ESI-MS-MS method for the quantitation of NO 711 was developed, and data from mass spectrometric detection were analyzed by nonlinear regression. Kinetic MS-binding experiments yielded values for k+1 and k-1, while in saturation MS-binding experiments, Kd and Bmax values were determined. In competitive MS-binding experiments, Ki values were obtained for various test compounds covering a broad range of affinities for mGAT1. All experiments were performed in 96-well plate format with a filter plate for the separation step which improved the efficiency and throughput of the procedure. The method was validated by classical radioligand-binding experiments with the labeled marker [3H2]NO 711 in parallel. The results obtained from MS-binding experiments were found to be in good agreement with the results of the radioligand-binding assays. The new kind of MS-binding assay presented herein is further adapted to the conventional radioligand-binding assay in that the amount of bound marker is securely quantified. This promises easy implementation in accordance with conventional binding assays without the major drawbacks that are inherent in radioligand or fluorescence binding assays. Therefore, MS-binding assays are a true alternative to classical radioligand-binding assays.     

1-（3-磺酸基）丙基-3-甲基咪唑磷钨酸盐催化合成柠檬酸三丁酯

以1-（3-磺酸基）丙基-3-甲基咪唑磷钨酸盐（［MIMPS］₃PW₁₂O₄₀）为催化剂,考察了醇酸物质的量比、反应时间和催化剂用量对合成柠檬酸三丁酯的影响及催化剂重复使用性能。结果表明,在醇酸物质的量比为4.0∶1、反应时间5 h、催化剂用量为柠檬酸质量的2%和反应温度不高于140 ℃条件下,酯化率高达99.7%,并具有良好重复使用效果。