Synthesis, conformation and PKC isozyme surrogate binding of indolinelactam-Vs, new conformationally restricted analogues of (−)-indolactam-V

New conformationally restricted analogues of tumor promoter (−)-indolactam-V (1), indolinelactam-Vs (8, 11) and their hexyl derivatives at position 1 or 7 (9, 10, 12, 13), were synthesized from 1. (3R)-Indolinelactam-V (8) adopted a conformation similar to the twist form of 1 with a cis amide, while the conformation of (3S)-indolinelactam-V (11) was close to that of the sofa form of 1 with a trans amide. 7-Hexyl derivatives of 8 and 11 (10, 13) showed binding affinities for C1 domains of protein kinase C (PKC) isozymes compared to 1, but exhibited little selectivity among these PKC isozymes. However, introduction of the hexyl group at position 1 of 8 and 11 significantly enhanced their binding selectivity for novel PKC isozymes. The best selectivity for novel PKC isozymes was observed in (3S)-1-hexylindolinelactam-V (12) with a sofa-like conformation. These results suggest that a sofa-restricted analogue of 1 with a hydrophobic chain at an appropriate position would be a promising lead for designing agents with a high selectivity for novel PKC isozymes.     

Using simplified protein representation as a reference potential for all-atom calculations of folding free energy

An effective approach for evaluating folding free-energy surfaces of explicit all-atom models is developed and examined. This approach is based on using the potential of a simplified protein model as a reference potential for calculating the free energy of the corresponding explicit model. Preliminary results are presented for the folding free energy of a 12-residue helix. The potential of the method for studies of protein-folding processes is discussed, emphasizing the ability to determine the difference between the results of simplified and explicit models. This can help in establishing the validity of simplified folding models. Received: 30 December 1998 / Accepted: 27 January 1999 / Published online: 5 May 1999     

Total synthesis and anticancer activity studies of the stereoisomers of asperphenamate and patriscabratine

<正>All stereoisomers of asperphenamate 1a and patriscabratine 2a were achieved with a high yield,and total synthesis of 2a is firstly described here.The absolute configuration of patriscabratine was determined as(S,S).The compounds 1a-d and 2a-d have been tested by MTT assay in T47D,MDA-MB231,HL60,Hela and SGC-7901 cell lines in vitro.Among them,the(R,S) stereoisomer shows the strongest anticancer effects,while the(S,R) shows the weakest one.     

Dendrimer-like supramolecular nanovalves based on polypseudorotaxane and mesoporous silica-coated magnetic graphene oxide: a potential pH-sensitive anticancer drug carrier

In the present research, two types of drug carriers based on mesoporous silica-coated magnetic graphene oxide, Fe₃O₄@GO@mSiO₂, were synthesised and the pH-responsive behaviour for doxorubicin release was investigated. One type of the carrier was dendrimer-like multi ethylene amine grafted on Fe₃O₄@GO@mSiO₂ and the other was dendrimer-like supramolecular polypseudorotaxane. Herein, α-cyclodextrin was used in the structure of supramolecular nanoparticles as a gatekeeper to inhibit the drug from escaping at neutral pH (the pH of healthy tissue). The drug release profile showed that the supramolecular nanocarrier was more sensitive to the pH changes. The content of drug release was about 100% at pH 5.5 (endosomal pH) during 48 h; but it was zero at pH 7.4. Also, the dendrimer structure facilitated the triggered release of doxorubicin.     

An efficient synthesis of new thiazolidin-4-one fused s-triazines as potential antimicrobial and anticancer agents

As a part of our endeavor toward the synthesis of new heterocyclic bioactive agents, two series of thiazolidin-4-one fused s-triazines were synthesized by applying an efficient palladium catalyzed C–C Suzuki coupling using catalyst system Pd(OAC)₂, Xphos and K₃PO₄ as a base in toluene solvent. Moreover, the synthesized analogs were further screened for their in vitro antimicrobial as well as anticancer efficacy against prostate cancer PC3 cells. Some compounds displayed remarkable antimicrobial activity and noticeable anticancer activity. It was observed that, both benzonitrile and nicotinonitrile are essential to increase the different pharmacological activities. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and MS analysis.     

The synthesis of new, selected analogues of the pro-apoptotic and anticancer molecule HA 14-1

A new and versatile strategy has been developed towards HA 14-1 analogues, selectively modified on position 4 and/or on the primary amine function. An important aspect was the appropriate selection of the phenol protective group in the 5-bromosalicylaldehyde, allowing the isolation of the key intermediate the 2H-benzopyrane-2-imine 2′.     

IR, Raman and theoretical ab initio RHF study of aminoglutethimide — an anticancer drug

A comparative analysis of the IR and Raman spectra of aminoglutethimide (AG) dissolved in CCl₄, CHCl₃ and CH₃CN was performed. Most of the absorption bands were assigned to characteristic group vibrations with the use of the IR and Raman spectra of deuterated AG, glutethimide, N-methyl glutethimide and glutarimide. The AG samples very weakly interacting with the environment were studied with the use of the Ar matrix isolation IR spectra. For comparison, the IR and Raman spectra of the crystalline samples formed by hydrogen-bonded AG molecules were recorded. The spectra were analyzed also in terms of normal modes and the harmonic approximation with the use of the ab initio restricted Hartree-Fock theory. It was found that increasing the solute concentration in CCl₄ and CHCl₃ leads to formation of the autoassociates. In CH₃CN the solute–solvent AG–CH₃CN dimers occur. Possible structures of the associates were theoretically studied on the model systems: the centrosymmetric glutarimide dimer and the linear AG–CH₃CN dimer. By a comparison of the theoretical and experimental spectra we were able to identify several peaks originating from the solute–solvent interactions.     

Novel efficient anticancer agents and DNA-intercalators of 1,2,3-triazol-1,8-naphthalimides: design, synthesis, and biological activity

Two novel series of 3-1,2,3-triazol-1,8-naphthalimides 5a-e, 7a-e were synthesized easily by employing ‘click reaction’. Their bioactivities were evaluated. Compounds 5a-e were found to be more toxic against MCF-7 cells while 7a-e were more potent against 7721 cells, in particular 7a, the IC₅₀ value of which against cell lines of MCF-7 and 7721 was 0.348 μM and 0.258 μM, respectively. Due to the phenyl group linked to 1,2,3-triazole, compound 5a not only showed higher DNA affinity but also more efficient DNA damaging ability than compound 7a.     

Total synthesis of (-)-balanol, all stereoisomers, their N-tosyl analogues, and fully protected ophiocordin: an easy route to hexahydroazepine cores from garner aldehydes

Total syntheses of (-)-balanol and all of its stereoisomers starting from easily available Garner aldehydes are described. Diastereoselective Grignard reactions on Garner aldehydes and ring-closing metatheses are the key steps for the construction of hexahydroazepine subunits. The benzophenone subunits were constructed through coupling of suitably functionalized aromatic aldehyde and bromo components. The synthetic route constitutes a convenient and scalable reaction sequence to generate all of the stereoisomers of balanol. The methodology is explored further for the synthesis of N-tosyl analogues of balanol and of fully protected ophiocordin.     

In-silico profiling,design, molecular docking computation,and drug kinetic model evaluation of novel curcumin derivatives as potential anticancer agents

The alarming trend of leukemia cell lines that are multidrug-resistant has prompted scientists to scramble for effective new anticancer treatments. Therefore, it remains an intriguing scientific task to optimize curcumin by trying to introduce molecular alteration to its vital structure to improve the biological effect against the P388 cell line or get around resistance phenomena. Regardless of the wide range of medications that are now being studied, Prednisone remains the most important and efficient part of chemotherapy that the WHO recommends. This article discusses the QSAR-oriented model and in silico assessment of some potent curcumin derivatives' anticancer activity against the P388 cell line. The solidity and propensity for prediction of the model were ensured by using stringent validation procedures. The activity of these derivatives was shown to be unrelated to lipophilicity, while shorter N-N distances and short substituents result in quite bioactive molecules. This information was used to design potent molecules that demonstrate good quality as per the assessment based on the Lead-Like Soft rule is acceptable for drug-like molecules. Also, molecule d2 does not possess any toxic effects risk alerts, suggesting drug-adherent conduct. While Prednisone the reference drug has a toxicity risk alert in red, suggesting non-adherent conduct for Prednisone. Hence, the novel molecules are promising anticancer agents.     

Synthesis of Benzofuran Analogue of Go6976, an Isoform‐Selective Protein Kinase C Inhibitor

Based on the structure of Go6976, a known isoform‐selective protein kinase C inhibitor, a benzofuran analogue (1) was designed. This analogue was synthesized by coupling of benzofuran 3‐acetic acid and 8‐oxo‐tryptamine and subsequent intramolecular Dieckmann condensation, alkylation, oxidative photocydization and cyanation reaction of mesylate.     

Metallomics for drug development: Serum protein binding and analysis of an anticancer tris(8-quinolinolato)gallium(III) drug using inductively coupled plasma mass spectrometry

The application of an inductively coupled plasma mass spectrometry (ICP-MS) assay for quantifying in vitro binding of a gallium-based anticancer drug, tris(8-quinolinolato)gallium(III), to serum albumin and transferrin and in human serum is described. The distribution of the drug between the protein-rich and protein-free fractions was assessed via ICP-MS measurement of total gallium in ultrafiltrates. Comparative kinetic studies revealed that the drug exhibits a different reactivity toward individual proteins. While the maximum possible binding to albumin (~10%) occurs practically immediately, interaction with transferrin has a step-like character and the equilibrium state (with more than 50% binding) is reached for about 48 h. Drug transformation into the bound form in serum, also very fast, results in almost quantitative binding (~95%). The relative affinity of protein–drug binding was characterized in terms of the association constants ranging from 10³ to 10⁴ M⁻¹. In order to further promote clinical testing of the gallium drug, the ICP-MS method was applied for direct quantification of gallium in human serum spiked with the drug. The detection limit for gallium was found to be as low as 20 ng L^–1. The repeatability was better than 8% (as RSD) and the achieved recoveries were in the range 99–103%.     

Synthesis,XRD, spectral,structural, quantum mechanical and anticancer studies of di(p-chlorobenzyl) (dibromo) (1, 10-phenanthroline) tin (IV) complex

The tin complex di (p-chlorobenzyl) (dibromo) (1, 10-phenanthroline) tin (IV) (4CLBR) was synthesised and subjected to characterization using spectroscopic techniques like FT-IR, Raman, ¹HNMR, ¹³CNMR, ¹¹⁹SnNMR, and crystallography. DFT method was used to compare theoretical and experimental results, and the theoretical method was done by the B3LYP/LanL2DZ. The VEDA programme package was used to design the entire vibrational spectral investigation. The Multiwfn software package was used to calculate the quantum chemical equations. A 2D network (C–H–Cl (C–Cl–H-benzyl, interactions forming a 2D network) and hydrogen bonding formed by bromine atoms such as C–H–Br (Sn–Br–H-Phen) were confirmed by X-rays as the complex and crystallisation. The crystal structure of the complex 4CLBR reveals that the tin atom is in a regular octahedral configuration. At the end of the day, anticancer activity has been investigated in this complex using a variety of cell lines, including PC3 (human prostate cancer cell), MCF7 (breast cancer cell), U937 (blood cancer cell), and U87 (brain cancer cell). The anticancer activity results clearly show that the complex 4CLBR and cisplatin have the same anticancer activity at concentrations of 15.6 g/ml against the U87 cell line.     

Design,synthesis and docking studies of new hydrazinyl-thiazole derivatives as anticancer and antimicrobial agents

Increase in the number of infections caused by pathogenic microbes in cancer patients has prompted the searcher to invest in the development of agents having dual anticancer and antimicrobial properties. The present study is concerned with synthesis and screening for anticancer and antimicrobial activity of a series of 5-hydrazinyl-2-(2-(1-(thien-2-yl)ethylidene)hydrazinyl)thiazole derivatives. The structure elucidation of the synthesized hydrazinyl thiazole derivatives was illustrated by spectroscopic and elemental analysis. All the newly synthesized compounds 5a-p were evaluated for in-vitro cytotoxic activity against breast carcinoma (MCF-7 cell line), hepatocellular carcinoma (HePG-2) and colorectal cancer (HCT-116) cell lines using MTT assay method. Compounds 5 g, 5h showed broad spectrum activity against three cancer cell lines with IC₅₀ ranged from 3.81 to 11.34 µM in compared to the reference drug Roscovitine (IC₅₀ = 9.32 to 13.82 µM), while compounds 5 l and 5 m were found to be more selective against HePG-2 and HCT-116 cell line (IC₅₀ = 9.29 and 8.93 µM respectively) and compound 5j was more selective against HePG-2 and MCF-7 cell lines (IC₅₀ = 6.73 and 10.87 µM respectively). The inhibitory activity of the most promising compounds was tested against the EGFR and ARO enzymes and were further tested for apoptosis and Annexin V/PI staining. The results of enzyme-based tests revealed that the tested compound 5j has a dual inhibitory effect on the EGFR and ARO enzymes with IC₅₀ = 82.8 and 98.6 nM respectively in compared to the reference drugs Erlotinib and Letrozole (IC₅₀ = 62.4 and 79 nM respectively). Furthermore, the majority of the tested hydrazinyl thiazole derivatives exhibited significant antimicrobial activity against the used pathogenic microbes species. Compounds 4b, 5h, 5j and 5 m exerted a good antibacterial and antifungal activity against all tested pathogenic microbes. Therefore, it was concluded that compounds 5 h, 5j and 5 m proved to possess dual anticancer and antimicrobial agent and may serves as a useful lead compounds in search for further modification or derivatization to give more potent and selective agents.     

Stereoselective synthesis of (3-aminodecahydro-1,4-methanonaphthalen-2-yl)methanols targeted to the C1 domain of protein kinase C

Protein kinase C (PKC) is a widely studied molecular target for the treatment of cancer and other diseases. We have approached the issue of modifying PKC function by targeting the C1 domain in the regulatory region of the enzyme. By using the X-ray crystal structure of the PKCδ C1b domain combined with molecular modeling, we discovered (3-aminodecahydro-1,4-methanonaphthalen-2-yl)methanol as a novel C1 domain ligand. The stereoselective synthesis of this tricyclic γ-amino alcohol was based on two successive Diels-Alder reactions to construct the six continuous stereocenters of the key intermediate.     

Design and characterization of an engineered gp41 protein from human immunodeficiency virus-1 as a tool for drug discovery

Two new proteins of approximately 70 amino acids in length, corresponding to an unnaturally-linked N- and C-helix of the ectodomain of the gp41 protein from the human immunodeficiency virus (HIV) type 1, were designed and characterized. A designed tripeptide links the C-terminus of the C-helix with the N-terminus of the N-helix in a circular permutation so that the C-helix precedes the N-helix in sequence. In addition to the artificial peptide linkage, the C-helix is truncated at its N-terminus to expose a region of the N-helix known as the “Trp-Trp-Ile” binding pocket. Sedimentation, crystallographic, and nuclear magnetic resonance studies confirmed that the protein had the desired trimeric structure with an unoccupied binding site. Spectroscopic and centrifugation studies demonstrated that the engineered protein had ligand binding characteristics similar to previously reported constructs. Unlike previous constructs which expose additional, shallow, non-conserved, and undesired binding pockets, only the single deep and conserved Trp-Trp-Ile pocket is exposed in the proteins of this study. This engineered version of gp41 protein will be potentially useful in research programs aimed at discovery of new drugs for therapy of HIV-infection in humans.     

New biodegradable hydrogels based on a photo-cross-linkable polyaspartamide and poly(ethylene glycol) derivatives. Release studies of an anticancer drug

 The functionalization of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) with glycidyl methacrylate (GMA) gives rise to a water-soluble photosensitive copolymer PHEA-GMA (PHG). Aqueous solutions of PHG alone or in combination with various concentrations of poly(ethylene glycol) dimethacrylate or poly(ethylene glycol) diacrylate (PEGDA) have been exposed to a source of UV rays at 313 nm in order to obtain polymeric networks. All samples have been prepared both as water-swellable microparticles and as gel systems. Microparticles have been characterised by Fourier transform IR spectrophotometry, dimensional analysis and swelling measurements in aqueous media mimicking biological fluids. In vitro chemical and enzymatic hydrolysis studies showed that all the prepared samples undergo a partial degradation at pH 1, 7.4 and 10 as well as after incubation with enzymes such as esterase. The effect of the cross-linking density on the rheological behavior of gel systems has also been investigated. PHG/PEGDA hydrogel is able to incorporate, during UV-irradiation, 5-fluorouracil (5-FU), chosen as a model drug, and to release it in simulated biological fluids, as confirmed by in vitro drug release studies at pH 1 and 7.4. PHG/PEGDA gel containing 5-FU is able to release this drug in a prolonged way, more slowly than a commercial ointment, as confirmed by in vitro studies at pH 5.5 and 7.4 using a Franz diffusion cell system and a synthetic membrane. Received: 3 October 2000 Accepted: 13 December 2000     

Schiff base stabilized silver nanoparticles as potential sensor for Hg(II) detection,and anticancer and antibacterial agent

This study reports a facile synthesis of silver nanoparticles (C3-AgNPs) by chemical route, using C3; 2,2′-((1E,1′E)-(propane-1,3-diylbis(azanylylidene))bis(methanylylidene))diphenol (3) and silver nitrate. The formation of nanoparticles was monitored using UV–Vis spectroscopy by the appearance of typical surface plasmon absorption maxima. The synthesized C3-AgNPs were characterized using Fourier-Transform-infrared (FTIR) and atomic force microscopy (AFM) techniques. In addition, the effect of concentration, temperature, time, pH, and stability in salts solution on C3-AgNPs was determined. From AFM, C3-AgNPs were found polydispersed with average size of 29.93 nm. Furthermore, the study reports C3-AgNPs as sensitive protocol for the detection of toxic metal; Hg(II) in tap water. From ten salts tested, C3-AgNPs demonstrated a sensitive and selective spectrophotometric signal and aggregation induced decrease of surface plasmon resonance (SPR) band. The nanosensor probe displayed a sensitive response to Hg(II) in a wide range of concentrations and pH. In addition, the decrease in SPR band of C3-AgNPs due to Hg(II) was not affected by tap water samples. C3-AgNPs also exhibited a redox catalytic potential in dyes degradation. In biological application, C3-AgNPs exhibited significant anticancer and antibacterial potential of 65 to 94% at 24–72 h, and inhibition zone of 7–18 mm, respectively. Hence, the synthesized C3-AgNPs could have promising application in environmental and pharmacological remediation.     

Microwave-assisted solid phase synthesis of Imatinib, a blockbuster anticancer drug

An expeditious, high yield and convenient synthesis of Imatinib was carried out on an aldehydic, super acid-sensitive resin, through an efficient, microwave-assisted synthetic protocol. The high versatility of the reaction scheme may enable the straightforward preparation of libraries of potential protein kinase inhibitors endowed with large molecular diversity.