Synthesis,structure and calculated NLO properties of [(n-Bu)2Sn-μ-O-μ-OH-Sn(n-Bu)2(CH3CO2)]2 and its putative derivatives

Title compound[(n-Bu)₂Sn-μ-O-μ-OH-Sn(n-Bu)₂(CH₃CO₂)]₂ was obtained accidentally by the reaction of n-Bu₂SnCl₂ with the metalloligand K₂[Ni(CDC)₂] in ethanol - water mixture while synthesizing a heterobimetallic complex [n-Bu₂Sn Ni(CDC)₂]. This has been characterized by micro analysis, UV–Vis, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy and the single crystal X-ray. The complex forms an interesting supramolecular architecture via (acetate)O?HO hydrogen bonding interactions which generates hydrophobic “pseudo-cage”. The electronic absorption bands of the title complex were assigned with the help of the time dependent density functional theory (TD-DFT) calculations. Density functional theory (DFT) calculations have been performed at the optimized molecular geometry of some of its putative derivatives e. g. trans p-amino cinnamic acid derivative 2; trans p-amino cinnamic acid and trans p-nitro cinnamic acid derivative 3; trans p-amino cinnamic acid and trans p-(N,N dimethylamino) cinnamic acid derivative 4. The first static hyperpolarizability (β) of the title compound and its derivatives were calculated with double numerical differentiation of total energies. The derivatives 3 and 4 showed three times and five times enhancement in the non-linear optical (NLO) responses than the standard p-nitroaniline (pNA).     

Study of the anticancer properties of tin(IV) carboxylate complexes on a panel of human tumor cell lines

A group of organotin(IV) complexes were prepared: [SnCy₃(DMNI)] ( 1 ), [SnCy₃(BZDO)] ( 2 ), [SnCy₃(DMFU)] ( 3 ), and [SnPh₂(BZDO)₂] ( 4 ), for which DMNIH=2,6‐dimethoxynicotinic acid, BZDOH=1,4‐benzodioxane‐6‐carboxylic acid, and DMFUH=2,5‐dimethyl‐3‐furoic acid. The cytotoxic activities of compounds 1 – 4 were tested against pancreatic carcinoma (PANC‐1), erythroleukemia (K562), and two glioblastoma multiform (U87 and LN‐229) human cell lines; they show very high antiproliferative activity, with IC₅₀ values in the 150–700 nM range after incubation for 72 h. Distribution of cellular DNA upon treatment with 1 – 4 revealed that whereas compounds 1 – 3 induce apoptosis in most of the cell lines, compound 4 does not affect cell viability in any cell line tested, indicating a possible difference in cytotoxic mechanism. Studies with the daunomycin‐resistant K562/R cell line expressing P‐glycoprotein (Pgp) showed that compounds 1 – 4 are not substrates of this protein efflux pump, indicating that these compounds do not induce acquisition of multidrug resistance, which is associated with the overexpression of Pgp.     

Preparation and some spectroscopic properties ofN-heterocyclic derivatives of a novel 1-pyrroline C18 fatty ester

A C₁₈ 1-pyrroline fatty ester, methyl 8-(5-hexyl-2-pyrrolin-1-yl)octanoate (1), was prepared from methyliso-ricinoleate. The C=N bond of the pyrroline ring was oxidized bym-chloroperoxy-benzoic acid to yield a mixture of oxaziridine isomers 2a,2b, which decomposed during gas chromatographic analysis to a 2,5-disubstituted pyrrole derivative, methyl 8-(5-hexyl-1H-pyrrole-2-)octanoate (3). Compound 3 was also obtained by reaction of 2a,2b with dilute HCl in methanol. Reaction of compound 1 with iodo-methane formed anN-methyl iminium iodide intermediate 4, which on reduction with sodium borohydride furnished a mixture ofcis/trans-N-methyl-2,5-disubstituted pyrrolidine derivatives, methyl 8-(cis/trans-5-hexyl-N-methyl-pyrrolidine-2-)octanoates 5a,5b. Reduction of compound 1 with NaBH₄ gave a mixture ofcis/trans-isomers of 2,5-disubstituted pyrrolidine derivatives, methyl 8-(5-hexyl-pyrrolidine-2-)octanoates 6a,6b. Acetylation of compounds 6a,6b with acetic anhydride furnished the correspondingN-acetyl pyrrolidines 7a,7b. When compound 1 was treated with perchloric acid, the corresponding iminium perchlorate derivative, methyl 8-(5-hexyl-1-pyrrolinium perchlorate-2-)octanoate 8 was obtained. The structures of the various derivatives were characterized by a combination of chromatographic, mass spectral and spectroscopic techniques.     

Access to New Cytotoxic Triterpene and Steroidal Acid-TEMPO Conjugates by Ugi Multicomponent-Reactions

Multicomponent reactions, especially the Ugi-four component reaction (U-4CR), provide powerful protocols to efficiently access compounds having potent biological and pharmacological effects. Thus, a diverse library of betulinic acid (BA), fusidic acid (FA), cholic acid (CA) conjugates with TEMPO (nitroxide) have been prepared using this approach, which also makes them applicable in electron paramagnetic resonance (EPR) spectroscopy. Moreover, convertible amide modified spin-labelled fusidic acid derivatives were selected for post-Ugi modification utilizing a wide range of reaction conditions which kept the paramagnetic center intact. The nitroxide labelled betulinic acid analogue 6 possesses cytotoxic effects towards two investigated cell lines: prostate cancer PC3 (IC₅₀ 7.4 ± 0.7 μM) and colon cancer HT29 (IC₅₀ 9.0 ± 0.4 μM). Notably, spin-labelled fusidic acid derivative 8 acts strongly against these two cancer cell lines (PC3: IC₅₀ 6.0 ± 1.1 μM; HT29: IC₅₀ 7.4 ± 0.6 μM). Additionally, another fusidic acid analogue 9 was also found to be active towards HT29 with IC₅₀ 7.0 ± 0.3 μM (CV). Studies on the mode of action revealed that compound 8 increased the level of caspase-3 significantly which clearly indicates induction of apoptosis by activation of the caspase pathway. Furthermore, the exclusive mitochondria targeting of compound 18 was successfully achieved, since mitochondria are the major source of ROS generation.     

Synthesis of dimethyl-substituted C18 furanoid fatty ester

Reaction of a C₁₈ furanoic fatty acid with dimethyl dicarboxylate (DMAD) furnished the corresponding bicyclo Diels-Alder adduct, which was partially hydrogenated over Pd/BaSO₄. Heat treatment (160–180°C) of the partially hydrogenated product caused a retro-Diels-Alder reaction to yield a furanoid fatty acid derivative containing methoxycarbonyl (COOCH₃) substituents at the 3-and 4-positions of the furan nucleus. Reduction of the COOCH₃ substituents with LiBH₄ gave the corresponding CH₂OH-substituted furanoid fatty acid. Hydrogenation of the latter over Pd/C furnished the desired dimethyl-substituted furanoid acid derivative (overall yield 60%). The spectroscopic properties of the intermediates and product are reported.     

Cytotoxic effects of ether lipids and derivatives in human nonneoplastic bone marrow cells and leukemic cells in vitro

The effects of 2-lysophosphatidylcholine (2-LPC), the alkyl lysophospholipid derivatives (ALP) 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH₃) and 1-O-hexadecyl-sn-glycero-3-phospho-trimethyl-ammonio-hexanol, the 2-acetamide analog of platelet-activating factor (PAF) 1-O-octadecyl-2-acetamide-sn-glycero-3-phosphocholine, the thioether lysophospholipid derivative (TLP) BM 41.440 and the ether-linked lipoidal amine CP-46,665 on tritiated thymidine uptake and trypan blue dye exclusion were tested in vitro in various freshly explanted cell samples from human nonneoplastic bone marrow and human leukemias. In both assay systems, a dose range of 1–20 μg/ml of the compounds was tested after 24, 48 and 72 hr of coincubation with the cells. The trypan blue dye exclusion revealed statistically significant preferential cytotoxicity in leukemic cells for three compounds with the order of quantitative selectiveness: ET-18-OCH₃>BM41.440>2-acetamide analog of PAF. CP-46,665 was the most toxic compound, but did not reveal significant differences between nonneoplastic bone marrow and leukemic cells when added in concentrations greater than 1 μg/ml. The trimethyl-ammoniohexanol compound showed only minor activity in the majority of tests, when added at concentrations <20 μg/ml. 2-LPC was rather ineffective. The tritiated thymidine uptake showed only preferential antiproliferative effects towards leukemic cells of ET-18-OCH₃ and, sometimes, within the dose time frame tested of BM 41.440. All compounds tested except 2-LPC and the trimethyl-ammonio-hexanol compound were active also in this assay (inhibition of uptake>50% of the controls). Based on these results, ET-18-OCH₃ and BM 41.440 are recommended for experimental bone marrow purging.     

Peptide Synthesis at High Pressure: Activation volume of a peptide coupling,synthesis of a glutathione derivative

From the pressure-induced rate enhancement the activation volume of the peptide coupling 1 with the sodium salt of glycine 2 leading to the corresponding dipeptide derivative 3 was determined to be strongly negative (ΔV^≠ = −(19.3 ± 0.5) cm³mol⁻¹ at 51.7 °C, CH₃OH). This finding indicates that and association with the developing of charge proceeds in the rate-determining transition state. The pressure-induced peptide coupling was exploited to synthesize a derivative ( 12a, b ) of glutathione (γ-Glu-Cys-Gly), a biologically important tripeptide, starting from either glycine or glutamic acid.     

High Efficiency Nucleating Agents of Polyoxymethylene

In this research, the effects of different kinds of nucleating agents on the crystallization and mechanical properties of polyoxymethylene (POM) were studied, including inorganic, organic, and polymer nucleating agents and their compounds. These properties showed that nanoCaCO₃, sorbitol derivative TMB-5, polyamide PA-4, and compound C-1/polyamide (PA)-4 can make spherulites of POM finer and more perfect, and effectively improve its notched impact toughness, in which the compound C-1/PA-4 displayed more remarkable nucleation effect. The study on the nonisothermal crystallization of POM showed that the crystallization temperature and crystallization growth rate of POM increased when C-1/PA-4 was added. The isothermal crystallization kinetics were also analyzed by the Avrami equation. The addition of C-1/PA-4 can increase the values of the Avrami exponent (n) and crystallization rate constant (k), and reduce the half-time of isothermal crystallization, t_1/2, and the time corresponding to the maximum rate of crystallization, t_P, indicating its remarkable nucleating effect on POM.     

Synthesis, Crystal Structure and Antitumor Activity of Ca(II) Coordination Polymer Based on 1,5-Naphthalenedisulfonate

A novel Ca(II) coordination polymer, [CaL(H₂O)₂] _n (L = 1,5-naphthalenedisulfonate), was synthesized by reaction of calcium perchlorate with 1,5-naphthalenedisulfonic acid sodium in CH₃CH₂OH/H₂O. It was characterized by elemental analysis, IR, ¹HNMR and thermal analysis. X-ray crystallographic reveals that the Ca(II) coordination polymer belongs to triclinic system, with space group P-1. The geometry of the Ca(II) ion is a distorted CaO₆ octahedron coordination environment, arising from its coordination by two water molecules, and four oxygen atoms from two l ligands. The Ca(II) ions are linked through the O atoms of 1,5-naphthalenedisulfonate ligands to form 1D chain structure. And then a 2D layered structure is constructed by hydrogen bonds and π–π stacking. The antitumor activity of 1,5-naphthalenedisulfonic acid sodium ligand and its Ca(II) coordination polymer against human hepatoma smmc-7721 cell line and human lung adenocarcinoma A549 cell line have been investigated.     

Synthesis and Pharmacological Evaluation of σ2 Receptor Ligands Based on a 3-Alkoxyisoxazole Scaffold: Potential Antitumor Effects against Osteosarcoma

Since its initial discovery as the basis for nicotinic acetylcholine receptor ligands, the 3-alkoxyisoxazole scaffold has been shown to be a versatile platform for the development of potent σ1 and σ2 receptor ligands. Herein we report a further SAR exploration of the 3-alkoxyisoxazole scaffold with the aim of obtaining potent σ2 receptor ligands. Various substitutions on the benzene ring and at the basic amino regions resulted in a total of 21 compounds that were tested for their binding affinities for the σ2 receptor. In particular, compound 51 [(2S)-1-(4-ammoniobutyl)-2-(((5-((3,4-dichlorophenoxy)methyl)isoxazol-3-yl)oxy)methyl)pyrrolidin-1-ium chloride] was identified as one of the most potent σ2 ligands within the series, with a K_i value of 7.9 nM. It demonstrated potent antiproliferative effects on both osteosarcoma cell lines 143B and MOS−J (IC₅₀ values of 0.89 and 0.71 μM, respectively), relative to siramesine (IC₅₀ values of 1.81 and 2.01 μM). Moreover, compound 51 inhibited clonal formation of osteosarcoma 143B cells at 1 μM, corresponding to half the dose required of siramesine for similar effects. The general cytotoxicity profile of compound 51 was assessed in a number of normal cell lines, including HaCaT, HAF, and LO2 cells. Furthermore, FACS analysis showed that compound 51 likely inhibits osteosarcoma cell growth by disruption of the cell cycle and promotion of apoptosis.     

Characterization of a Novel Amphiphilic Cationic Chlorin Photosensitizer for Photodynamic Applications

A novel amphiphilic cationic chlorin e₆ derivative was investigated as a promising photosensitizer for photodynamic therapy. Two cationic –N(CH₃)₃⁺ groups on the periphery of the macrocycle provide additional hydrophilization of the molecule and ensure its electrostatic binding to the mitochondrial membranes and bacterial cell walls. The presence of a hydrophobic phytol residue in the same molecule results in its increased affinity towards the phospholipid membranes while decreasing its stability towards aggregation in aqueous media. In organic media, this chlorin e₆ derivative is characterized by a singlet oxygen quantum yield of 55%. Solubilization studies in different polymer- and surfactant-based supramolecular systems revealed the effective stabilization of this compound in a photoactive monomolecular form in micellar nonionic surfactant solutions, including Tween-80 and Cremophor EL. A novel cationic chlorin e₆ derivative also demonstrates effective binding towards serum albumin, which enhances its bioavailability and promotes effective accumulation within the target tissues. Laser confocal scanning microscopy demonstrates the rapid intracellular accumulation and distribution of this compound throughout the cells. Together with low dark toxicity and a rather good photostability, this compound demonstrates significant phototoxicity against HeLa cells causing cellular damage most likely through reactive oxygen species generation. These results demonstrate a high potential of this derivative for application in photodynamic therapy.     

2‐Aminothiazoles with Improved Pharmacotherapeutic Properties for Treatment of Prion Disease

Recently, we described the aminothiazole lead (4‐biphenyl‐4‐ylthiazol‐2‐yl)‐(6‐methylpyridin‐2‐yl)‐amine ( 1 ), which exhibits many desirable properties, including excellent stability in liver microsomes, oral bioavailability of ～40 %, and high exposure in the brains of mice. Despite its good pharmacokinetic properties, compound 1 exhibited only modest potency in mouse neuroblastoma cells overexpressing the disease‐causing prion protein PrP^Sc. Accordingly, we sought to identify analogues of 1 with improved antiprion potency in ScN2a‐cl3 cells while retaining similar or superior properties. Herein we report the discovery of improved lead compounds such as (6‐methylpyridin‐2‐yl)‐[4‐(4‐pyridin‐3‐yl‐phenyl)thiazol‐2‐yl]amine and cyclopropanecarboxylic acid (4‐biphenylthiazol‐2‐yl)amide, which exhibit brain exposure/EC₅₀ ratios at least tenfold greater than that of compound 1 .     

Highly diastereoselective synthesis of novel polymers via tandem Diels–Alder–ene reactions

Cis -9,10-dihydro-9,10-ethanoanthracene-11-12-dicarboxylic acid anhydride (1) was converted into its amic acid derivative by reaction with L -leucine. The cyclization reaction was carried out in situ using triethylamine to give the succinic imide-acid derivative (2). Compound (2) was converted to the acid chloride (3) by reaction with thionyl chloride. The reaction of acid chloride (3) with isoeugenol (4) was carried out in chloroform and a novel optically active isoeugenol ester derivative (5) was obtained in high yield. 4-Phenyl-1,2,4-triazoline-3,5-dione (PhTD) (6) was allowed to react with compound (5). The reaction is very fast and gives only one diastereoisomer of (7) via Diels–Alder and ene pathways in quantitative yield. Compound (7) was characterized by ¹H NMR, IR, specific rotation and elemental analysis, and was used as a model for the polymerization reactions. The polymerization reactions of compound (5) with bis-triazolinediones (8), (9) were performed in N,N-dimethylacetamide (DMAc) at room temperature. The reactions are exothermic and fast, and give novel optically active polymers. Some physical properties and structural characterizations of these new polymers have been studied, and are reported. © 1999 Society of Chemical Industry     

Novel silicon-containing analogues of the retinoid agonist bexarotene: syntheses and biological effects on human pluripotent stem cells

Twofold sila‐substitution (C/Si exchange) of the clinically used RXR‐selective retinoid agonist bexarotene leads to disila‐bexarotene, which displays pharmacological potency similar to that of the parent carbon compound, as shown in a HeLa‐cell‐based RXR assay. Formal exchange of the SiCH₂CH₂Si group in disila‐bexarotene with a SiCH₂Si or SiOSi moiety leads to the disila‐bexarotene analogues 8 and 9 . The silicon compounds 8 and 9 were synthesized in multistep syntheses, starting from HC?C(CH₃)₂SiCH₂Si(CH₃)₂C?CH and HC?C(CH₃)₂SiOSi(CH₃)₂C?CH, respectively. The key step in the syntheses of 8 and 9 is a cobalt‐catalyzed [2+2+2] cycloaddition reaction that affords the 1,3‐disilaindane and 2‐oxa‐1,3‐disilaindane skeletons. Disila‐bexarotene and its analogues 8 and 9 were studied for their biological effects relative to all‐trans retinoic acid in cultured human pluripotent stem cells. The parent carbon compound bexarotene was included in some of these biological studies. Although the silicon‐containing bexarotene analogues disila‐bexarotene, 8 , and 9 appear not to regulate the differentiation of TERA2.cl.SP12 stem cells, preliminary evidence indicates that these compounds may possess enhanced functions over the parent compound bexarotene, such as induction and regulation of cell death and cell numbers. The biological data obtained indicate that bexarotene, contrary to the silicon‐containing analogues disila‐bexarotene, 8 , and 9 , may partially act to induce cell differentiation.     

Resveratrol-like Compounds as SIRT1 Activators

The sirtuin 1 (SIRT1) activator resveratrol has emerged as a promising candidate for the prevention of vascular oxidative stress, which is a trigger for endothelial dysfunction. However, its clinical use is limited by low oral bioavailability. In this work, we have applied a previously developed computational protocol to identify the most promising derivatives from our in-house chemical library of resveratrol derivatives. The most promising compounds in terms of SIRT1 activation and oral bioavailability, predicted in silico, were evaluated for their ability to activate the isolated SIRT1 enzyme. Then, we assessed the antioxidant effects of the most effective derivative, compound 3d, in human umbilical vein endothelial cells (HUVECs) injured with H₂O₂ 100 µM. The SIRT1 activator 3d significantly preserved cell viability and prevented an intracellular reactive oxygen species increase in HUVECs exposed to the oxidative stimulus. Such effects were partially reduced in the presence of a sirtuin inhibitor, sirtinol, confirming the potential role of sirtuins in the activity of resveratrol and its derivatives. Although 3d appeared less effective than resveratrol in activating the isolated enzyme, the effects exhibited by both compounds in HUVECs were almost superimposable, suggesting a higher ability of 3d to cross cell membranes and activate the intracellular target SIRT1.     

The microwave-assisted synthesis and characterization of novel metal-free and metallophthalocyanines peripherally fused to four 13-membered diazadithia macrocycles

The novel tetrasubstituted metal-free phthalocyanine and metallophthalocyanines 7, bearing four 13-membered diazadithia macrocycle moieties at peripheral positions were synthesized by cyclotetramerization of the corresponding phthalonitrile derivative in a multi-step reaction sequence. The metal-free phthalocyanine was synthesized by microwave irradiation of the corresponding dicyano compound in 2-(dimethylamino)ethanol for 10 min. Metallophthalocyanines were obtained from the respective dicyano derivative and corresponding anhydrous metal salts NiCl₂ and ZnCl₂, CoCl₂, CuCl₂, respectively, by microwave irradiation in 2-(dimethylamino)ethanol at 175 °C, 350 W for 10 min. The new compounds were characterized by a combination of IR, ¹H NMR, ¹³C NMR, UV–vis, elemental analysis and MS spectral data.     

Deuterated Curcuminoids: Synthesis,Structures, Computational/Docking and Comparative Cell Viability Assays against Colorectal Cancer

A series of deuterated curcuminoids (CUR) were synthesized, bearing two to six OCD₃ groups, in some cases in combination with methoxy groups, and in others together with fluorine or chlorine atoms. A model ring-deuterated hexamethoxy-CUR–BF₂ and its corresponding CUR compound were also synthesized from a 2,4,6-trimethoxybenzaldehyde-3,5-d₂ precursor. As with their protio analogues, the deuterated compounds were found to remain exclusively in the enolic form. The antiproliferative activities of these compounds were studied by in vitro bioassays against a panel of 60 cancer cell lines, and more specifically in human colorectal cancer (CRC) cells (HCT116, HT29, DLD-1, RKO, SW837, and Caco2) and in normal colon cells (CCD841CoN). The deuterated CUR–BF₂ adducts exhibited better overall growth inhibition by NCI-60 assay, while for other CUR–BF₂ adducts the non-deuterated analogues were more cytotoxic. Results of the more focused comparative cell viability assays followed the same trend, but with some variation depending on cell lines. The CUR–BF₂ adducts exhibited significantly higher cytotoxicity than CURs. Structural studies (X-ray and DFT) and computational molecular docking calculations comparing their inhibitory efficacy with those of known anticancer agents used in chemotherapy are also reported.     

Anticancer Gold(III) Peptidomimetics: From Synthesis to in vitro and ex vivo Biological Evaluations

Five new Au^III‐peptidodithiocarbamato complexes of the type [Au^IIIBr₂(dtc‐AA₁‐AA₂‐OR] (in which AA₁=N‐methylglycine (Sar), l /d ‐Pro; AA₂=l /d ‐Ala, α‐aminoisobutyric acid (Aib); R=OtBu, triethylene glycol methyl ether), differing with regard to the amino acid sequence and/or the chiral amino acid configuration, were designed to enhance tumor selectivity and bioavailability. The gold(III)‐based moiety was functionalized to exploit the targeting properties of the peptidomimetic ligand toward two peptide transporters (namely PEPT1 and PEPT2), which are upregulated in several tumor cells. The compounds were synthesized and fully characterized, mainly by means of elemental analysis, one‐ and two‐dimensional NMR spectroscopy, FT‐IR, and UV/Vis spectrophotometry. The crystal structures of three compounds were also solved by X‐ray diffraction. In vitro cytotoxicity studies using a panel of human tumor cell lines (A549 [non‐small‐cell lung carcinoma], MCF‐7 [breast cancer], A2780 [ovarian carcinoma], H1975 [non‐small‐cell lung carcinoma], H460 [large‐cell lung carcinoma], and A431 [human epidermoid carcinoma]) showed the dtc‐Pro‐Aib‐OtBu derivative to be very effective, with GI₅₀ values much lower than those of cisplatin. This complex was thus selected for evaluating stability under physiological conditions and possible interactions with serum albumin, as well in PARP‐1 enzyme inhibition assays and preliminary ex vivo toxicity experiments on healthy rat tissues.     

The Neurotrophin Receptor TrkC as a Novel Molecular Target of the Antineuroblastoma Action of Valproic Acid

Neurotrophins and their receptors are relevant factors in controlling neuroblastoma growth and progression. The histone deacetylase (HDAC) inhibitor valproic acid (VPA) has been shown to downregulate TrkB and upregulate the p75NTR/sortilin receptor complex. In the present study, we investigated the VPA effect on the expression of the neurotrophin-3 (NT-3) receptor TrkC, a favorable prognostic marker of neuroblastoma. We found that VPA induced the expression of both full-length and truncated (TrkC-T1) isoforms of TrkC in human neuroblastoma cell lines without (SH-SY5Y) and with (Kelly, BE(2)-C and IMR 32) MYCN amplification. VPA enhanced cell surface expression of the receptor and increased Akt and ERK1/2 activation by NT-3. The HDAC inhibitors entinostat, romidepsin and vorinostat also increased TrkC in SH-SY5Y, Kelly and BE(2)-C but not IMR 32 cells. TrkC upregulation by VPA involved induction of RUNX3, stimulation of ERK1/2 and JNK, and ERK1/2-mediated Egr1 expression. In SH-SY5Y cell monolayers and spheroids the exposure to NT-3 enhanced the apoptotic cascade triggered by VPA. Gene silencing of both TrkC-T1 and p75NTR prevented the NT-3 proapoptotic effect. Moreover, NT-3 enhanced p75NTR/TrkC-T1 co-immunoprecipitation. The results indicate that VPA upregulates TrkC by activating epigenetic mechanisms and signaling pathways, and sensitizes neuroblastoma cells to NT-3-induced apoptosis.      

Scouting around 1,2,3,4-Tetrahydrochromeno[3,2-c]pyridin-10-ones for Single- and Multitarget Ligands Directed towards Relevant Alzheimer's Targets

A number of 1,2,3,4-tetrahydrochromeno[3,2-c]pyridin-10-one derivatives have been synthesized and screened against different targets involved in the onset and progression of Alzheimer's disease (AD), such as acetyl- and butyrylcholinesterase (AChE and BChE), monoamine oxidases A and B (MAO A and B), aggregation of β-amyloid (Aβ) and reactive oxygen species (ROS) production. Derivatives 1 c , 3 b , 4 and 5 a showed multifaceted profiles of promising anti-AD features and returned well-balanced multitargeting inhibitory activities. Moreover, compound 1 f , a potent and selective human MAO B inhibitor (IC₅₀=0.89 μM), proved to be a safe neuroprotectant in a human neuroblastoma cell line (SH-SY5Y) by improving viability impaired by Aβ_1–42 and pro-oxidant insult. Furthermore, structure–activity relationships (SARs) and docking models were derived in order to assist further hit-to-lead optimization stage.