Search

6-Substituted purine and 9-β-d-ribofuranosyl purine analogues were synthesized and their biological activities were evaluated. CD Spectra and thermal melting studies showed that compounds 8, 9, 10 could interact with RNA and DNA in solution. Compound 8 and 10 may bind with RNA single strand and interfere the formation of RNA duplex. Among of these compounds, compound 8 showed middle inhibition on the growth of HeLa cells (70.21%) and HL-60 cells (70.85%) at 10 μM. Comparing to the structures of these synthetic compounds, it may indicate that the sugar moiety and the 6-amino side chain of nucleoside 8 play an important role in the biological activities. [Copyright &y& Elsevier]

Abstract: A new SASRIN resin derivative, SASRIN–TOPCAT resin, was synthesized by the reaction of SASRIN resin with 2-thiopyridyl chloroformate. The new resin can be used for the loading of alcohols and thiols under neutral conditions, and the release of alcohol from the resin is achieved by the treatment of 1% TFA in CH2Cl2 for 15–60min. Compared to the other reported resins, SASRIN–TOPCAT resin is more suitable for the loading of alcohols in solid-phase organic synthesis. [Copyright &y& Elsevier]

Abstract: Selective deprotection of primary acetyl ester in nucleosides and carbohydrates using 1% iodine–methanol solution (w/v) was described and the mechanism was also discussed. [Copyright &y& Elsevier]

Two series of 6′-halovinyl-adenosine stereoisomers including 5′-ethylenic and acetylenic substituted l-adenosine, 5′-ethylenic and acetylenic substituted isonucleosides were synthesized. In the l-nucleoside series, compounds 6b, 8b, 10b and 13b showed modest inhibition of SAH hydrolase (21, 44, 50 and 26% respectively) at 100μM. The l-isomers of 5′-ethylenic and acetylenic modified isonucleoside 23, 24 exhibited no activity for the inhibition of SAH hydrolase, however, the d-isomers 30 and 31 showed some activities in the same test (35 and 21%). It indicated clearly the strict stereochemical requirement for the substrate of SAH hydrolase. Compounds 6b, 8b, 8c, 11b exhibited modest to good inhibition effects on the growth of HeLa cells or Bel-7420 cells at 1μM (64, 44, 53 and 82% respectively). [Copyright &y& Elsevier]

Background: The toxicity of excessive glutamate release has been implicated in various acute and chronic neurodegenerative conditions. Vesicular glutamate transporters (VGLUTs) are the major mediators for the uptake of glutamate into synaptic vesicles. However, the dynamics and mechanism of this process in glutamatergic neurons are still largely unknown.Objective: This study aimed to investigate the candidate protein partners of VGLUT1 and their regulatory roles in the vesicles in rat brain.Methods: Pull down assay, co-immunoprecipitation assay, or split-ubiquitin membrane yeast two hybrid screening coupled with nanoRPLC-MS/MS were used to identify the candidate protein partners of VGLUT1 in the vesicles in rat brain. The in vitro and in vivo models were used to test effects of AβPP, Atp6ap2, Gja1, and Synataxin on VGLUT1 expression.Results: A total of 255 and 225 proteins and 172 known genes were identified in the pull down assay, co-immunoprecipitation assay, or split-ubiquitin yeast two-hybrid screening respectively. The physiological interactions of SV2A, Syntaxin 12, Gja1, AβPP, and Atp6ap2 to VGLUT1 were further confirmed. Knockdown of Atp6ap2, Gja1, and Synataxin increased VGLUT1 mRNA expression and only knockdown of AβPP increased both mRNA and protein levels of VGLUT1 in PC12 cells. The regulatory function of AβPP on VGLUT1 expression was further confirmed in the in vitro and in vivo models.Conclusion: These results elucidate that the AβPP and VGLUT1 interacts at vesicular level and AβPP plays a role in the regulation of VGLUT1 expression which is essential for maintaining vesicular activities. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a series of bioreducible poly(amidoamine)s grafting different percentages of cholesterol (rPAA-Ch14: 14%, rPAA-Ch29: 29%, rPAA-Ch57: 57% and rPAA-Ch87: 87%) was synthesized and used for siRNA delivery. These amphiphilic polymers were able to self-assemble into cationic nanoparticles in aqueous solution at low concentrations. The nanoparticle formation was evidenced via cryo-transmission electron microscope (Cryo-TEM) and dynamic light scattering analysis. The average hydrodynamic size of rPAA-Ch blank nanoparticles was about 80–160 nm with zeta potential of 50–60 mV. Also, the effects of different percentages of cholesterol grafted onto rPAA on physicochemical characteristics, in vitro cytotoxicity, cellular uptake, VEGF gene silencing efficacy and translocation mechanism of rPAA-Ch/siRNA complexes were investigated. The results showed that rPAA-Ch57 polymer was not only able to form stable nanocomplexes and possess high cell uptake, but also to exhibit the best in vitro VEGF gene silencing efficacy and the best in vivo tumor growth inhibition effect when it was formulated with VEGF-siRNA. Moreover, the observations of confocal laser scanning microscope (CLSM) and the study of cholesterol competitive inhibition demonstrated that endosomal/lysosomal escape and cytoplasmic dissociation of rPAA-Ch57/siRNA complexes were dependent on the “proton sponge effect” and disulfide cleavage, following internalization with cholesterol-related endocytosis pathway and subsequent transportion into endosomes/lysosomes. These findings indicated that the rPAA-Ch57 polymer should be a promising and potent carrier for siRNA delivery. [Copyright &y& Elsevier]

Abstract: Due to the absence of safe and effective carriers for in vivo delivery, the applications of small interference RNA (siRNA) in clinic for therapeutic purposes have been limited. In this study, a biodegradable amphiphilic tri-block copolymer (mPEG2000-PLA3000-b-R15) composed of monomethoxy poly(ethylene glycol), poly(d,l-lactide) and polyarginine was synthesized and further self-assembled to cationic polymeric nanomicelles for in vivo siRNA delivery, with an average diameter of 54.30 ± 3.48 nm and a zeta potential of approximately 34.8 ± 1.77 mV. The chemical structures of the copolymers were well characterized by 1H NMR spectroscopy and FT-IR spectra. In vitro cytotoxicity and hemolysis assays demonstrated that the polymeric nanomicelles showed greater cell viability and haemocompatibility than those of polyethyleneimine (PEI) or R15 peptide. In vitro experiments demonstrated that EGFR targeted siRNA formulated in micelleplexes exhibited approximately 65% inhibition of EGFR expression on MCF-7 cells in a sequence-specific manner, which was comparable to Lipofectamine™ 2000. The results of intravenous administration showed Micelleplex/EGFR-siRNA significantly inhibited tumor growth in nude mice xenografted MCF-7 tumors, with a remarkable inhibition of EGFR expression. Furthermore, no positive activation of the innate immune responses and no significant body weight loss was observed during treatment suggested that this polymeric micelle delivery system is non-toxic. In conclusion, the present nanomicelles based on cationic mPEG2000-PLA3000-b-R15 copolymer would be a safe and efficient nanocarrier for in vivo delivery of therapeutic siRNA. [Copyright &y& Elsevier]

Abstract: Gemcitabine (GEM) is a nucleoside analog agent against a wide variety of tumors. To overcome its limitation of rapid metabolism in vivo that results in short circulation time and poor antitumor efficacy, a novel prodrug (CLA–GEM conjugate) has been developed through the covalent coupling of conjugated linoleic acid (CLA) to N4-amino group of GEM. The chemical structure of CLA–GEM conjugate was identified by NMR, FTIR and other methods. From in vitro tests, it was demonstrated that the linkage with CLA increased the plasma stability of GEM as well as the antitumor activity against human breast tumor cells (MCF-7). Importantly, it also altered the transport pattern of GEM across cell membrane (MCF-7 and MDA-MB-231), evidenced by the little effect of nucleoside transporter inhibitors (NBMPR and dipyridamole) on the IC50 values of CLA–GEM, instead of the great effect on that of unmodified GEM. In vivo pharmacokinetic study showed that the CLA–GEM conjugate had a longer plasma half-life and a higher bioavailability compared to that of unmodified GEM. Significant stronger antitumor activity was observed in the nude mice xenografted MCF-7 breast tumor after treated with CLA–GEM than that of unmodified GEM, while no significant body weight loss was found in all treatments. In conclusion, the novel CLA–GEM conjugate prepared in this study would be a promising prodrug of gemcitabine for future clinical use. [Copyright &y& Elsevier]

Abstract: Purpose: The restriction of drug transporting across the blood–brain barrier (BBB) and the limit of drug penetrating into the tumor tissue remain the major obstacles for brain tumor chemotherapy. In the present study, we developed a functionalized liposomal nanoconstruct, epirubicin liposomes modified with tamoxifen (TAM) and transferrin (TF), for transporting drug across the BBB and afterwards targeting the brain glioma. Methods: Evaluations were performed on the murine C6 glioma cells, the C6 glioma spheroids, the BBB model in vitro and the brain glioma-bearing rats. Results: When compared with controls, epirubicin liposomes modified with TAM and TF showed the strongest inhibitory effect to C6 glioma cells or glioma spheroids in vitro, significant transport ability across the BBB model in vitro, an evident effect of targeting the brain tumor cells in vitro, and an extended median survival time in the brain glioma-bearing rats. Conclusion: Epirubicin liposomes modified with TAM and TF significantly improve the therapeutic efficacy of brain glioma in vitro and in animals, hence providing a new strategy for brain tumor chemotherapy. [ABSTRACT FROM AUTHOR]

Abstract: Chemotherapy for brain glioma has been of limited value due to the inability of transport of drug across the blood-brain barrier (BBB) and poor penetration of drug into the tumor. For overcoming these hurdles, the dual-targeting daunorubicin liposomes were developed by conjugating with p-aminophenyl-α-D-manno-pyranoside (MAN) and transferrin (TF) for transporting drug across the BBB and then targeting brain glioma. The dual-targeting effects were evaluated on the BBB model in vitro, C6 glioma cells in vitro, avascular C6 glioma tumor spheroids in vitro, and C6 glioma-bearing rats in vivo, respectively. After applying dual-targeting daunorubicin liposomes, the transport ratio across the BBB model was significantly increased up to 24.9%. The most significant uptake by C6 glioma was evidenced by flow cytometry and confocal microscope. The C6 glioma spheroid volume ratio was significantly lowered to 54.7%. The inhibitory rate to C6 glioma cells after crossing the BBB was significantly enhanced up to 64.0%. The median survival time of tumor bearing rats after administering dual-targeting daunorubicin liposomes (22days) was significantly longer than that after giving free daunorubicin (17days, P =0.001) or other controls. In conclusion, the dual-targeting daunorubicin liposomes are able to improve the therapeutic efficacy of brain glioma in vitro and in animals. [Copyright &y& Elsevier]

Intracellular Ca2+ mobilization plays an important role in a wide variety of cellular processes, and multiple second messengers are responsible for mediating intracellular Ca2+ changes. Here we explored the role of one endogenous Ca2+-mobilizing nucleotide, cyclic adenosine diphosphoribose (cADPR), in the proliferation and differentiation of neurosecretory PC12 cells. We found that cADPR induced Ca2+ release in PC12 cells and that CD38 is the main ADP-ribosyl cyclase responsible for the acetylcholine (ACh)-induced cADPR production in PC12 cells. In addition, the CD38/cADPR signaling pathway is shown to be required for the ACh-induced Ca2+ increase and cell proliferation. Inhibition of the pathway, on the other hand, accelerated nerve growth factor (NGF)-induced neuronal differentiation in PC12 cells. Conversely, overexpression of CD38 increased cell proliferation but delayed NGF-induced differentiation. Our data indicate that cADPR plays a dichotomic role in regulating proliferation and neuronal differentiation of PC12 cells. [ABSTRACT FROM AUTHOR]

Abstract: Two types of neamine derivatives, neamine-dinucleotide conjugates 8a–g and neamine-PNA conjugates 12a–c and 14a–d, were synthesized. Compound 8a–g were synthesized by the condensation of azido-neamine with dinucleotide-5′-carboxylic acids, followed by reduction and deprotection. Compound 12a–c and 14a–d were synthesized by the similar strategy. The binding affinities of conjugates 8a–g, 12a–c, and 14a–d towards 16S RNA, 18S RNA, and TAR RNA were evaluated by SPR. It indicates that conjugates 12a–c and 14a–d interact with 16S, 18S RNA at the same level as that of neamine, 14a and 14d show about twofold binding affinities to TAR RNA compared to that of neamine. However, the neamine-dinucleotide conjugates 8a–g exhibit very weak binding affinities to 16S, 18S, and TAR RNA, computer modelling results that negative–negative electrostatic repulsion of phosphate group in compound 8a–g and RNA leads to a sharp decrease of the binding affinities compared with that of neamine, neamine-nucleoside and neamine-PNA conjugates. [Copyright &y& Elsevier]

Abstract: Two synthetic strategies were developed to obtain isonucleosides 2a and 2b. Starting from the known compound 4, an extension of one carbon unit at sugar 6-terminal was achieved by Wittig reaction and Stannyl-desulfonylation reaction. After oxidation of the double bond, the isonucleosides with elongated side chain 2a and 2b were synthesized. For the synthesis of isonucleosides containing different bases, an epoxide intermediate approach was developed. Isonucleosides 2a and 2b were synthesized by regioselective epoxide opening reaction of 18 in good yield. [Copyright &y& Elsevier]

Abstract: Our studies of the TIBAL-promoted Claisen rearrangement reaction and ring-closing metathesis (RCM) resulted in the development of an efficient synthetic route to polyfunctional seven-membered carbasugar synthons from d-arabinose. Moreover, the construction of 8-oxa-bicyclo[3.2.1]octane derivatives 10 and 13 was achieved by BCl3 or iodide-promoted intramolecular electrophilic addition reactions, which were regio- and stereoselective. [Copyright &y& Elsevier]

Abstract: 3,6-Di-O-methanesulfonyl-2,5-anhydro-l-idofuranose dimethyl acetal 9 was reacted with NaN3 in DMF to give 6-azido substituted carbohydrate 10 selectively. A series of 6-amino-isonucleosides 4a–d were synthesized by the reaction of nucleobases with epoxide 13, followed by hydrolysis, reduction, and deprotection, in good yield. [Copyright &y& Elsevier]

Abstract: Two types of aminodisaccharide–nucleoside conjugates were synthesized by the condensation of azidodisaccharide and nucleoside using aliphatic diamine as a linker. The corresponding azidodisaccharides could be yielded from neamine in good yield. The binding properties to 16S RNA of these conjugates were evaluated by SPR. It was found that the nucleobase played a significant role in the binding of these conjugates to 16S RNA and a shorter linker between the aminodisaccharide and nucleoside was favorable for 16S RNA binding. [Copyright &y& Elsevier]

Abstract: Several tricyclic azido-isonucleosides were formed in high yields by the treatment of pyrimidine isonucleosides with triphenylphosphine, tetrabromomethane, and sodium azide. The regioselective ring opening of these tricyclic azido-isonucleosides was also investigated. [Copyright &y& Elsevier]

Focuses on the synthesis of the chiral specificity of platinum complexes in their cross-membrane transport and DNA molecular recognition. Effects of the chiral features and stereochemistry of newly-synthesized complexes on their anticancer activity; Specific integration of DNA with three different chiral complexes.

N-glycosylation is instrumental to the regulation of CD147 functions, including the maturation of CD147, secretion of matrix metalloproteinases (MMPs), and promotion of tumor metastasis. Glycosylated CD147 is highly expressed in various cancer types, participates in metastasis, and is associated with the poor prognosis of malignant tumors. However, to date, there has been little development of target-specific inhibitors for CD147 glycosylation. In this work, we report a strategy for discovering CD147 glycosylation inhibitors through computer-aided screening and inhibition assays. Four compounds were screened as potential CD147 glycosylation inhibitors. Of these, compound 72 was finally identified as the best candidate. Further experiments confirmed that compound 72 inhibited the production of MMPs and the metastasis of cancer cells in the Hela cell line. Results further suggest that compound 72 could promote the expression of E-cadherin by targeting CD147, thereby inhibiting tumor migration. Finally, the structures of the other potential CD147 N-glycosylation inhibitors may eventually provide guidance for future optimization. [ABSTRACT FROM AUTHOR]

Concomitant inhibition of MAPK and PI3K signaling pathways has been recognized as a promising strategy for cancer therapy, which effectively overcomes the drug resistance of MAPK signaling pathway-related inhibitors. Herein, we report the scaffold-hopping generation of a series of 1H-pyrazolo[3,4-d]pyrimidine dual ERK/PI3K inhibitors. Compound 32d was the most promising candidate, with potent inhibitory activities against both ERK2 and PI3Kα which displays superior anti-proliferative profiles against HCT116 and HEC1B cancer cells. Meanwhile, compound 32d possessed acceptable pharmacokinetic profiles and showed more efficacious anti-tumor activity than GDDC-0980 and the corresponding drug combination (BVD-523 + GDDC-0980) in HCT-116 xenograft model, with a tumor growth inhibitory rate of 51% without causing observable toxic effects. All the results indicated that 32d was a highly effective anticancer compound and provided a promising basis for further optimization towards dual ERK/PI3K inhibitors. [ABSTRACT FROM AUTHOR]

Chalcone is a common scaffold found in many biologically active compounds. The chalcone scaffold was also frequently utilized to design novel anticancer agents with potent biological efficacy. Aiming to continue the research of effective chalcone derivatives to treat cancers with potent anticancer activity, fourteen amino chalcone derivatives were designed and synthesized. The antiproliferative activity of amino chalcone derivatives was studied in vitro and 5-Fu as a control group. Some of the compounds showed moderate to good activity against three human cancer cells (MGC-803, HCT-116 and MCF-7 cells) and compound 13e displayed the best antiproliferative activity against MGC-803 cells, HCT-116 cells and MCF-7 cells with IC50 values of 1.52 μM (MGC-803), 1.83 μM (HCT-116) and 2.54 μM (MCF-7), respectively which was more potent than the positive control (5-Fu). Further mechanism studies were explored. The results of cell colony formatting assay suggested compound 10e inhibited the colony formation of MGC-803 cells. DAPI fluorescent staining and flow cytometry assay showed compound 13e induced MGC-803 cells apoptosis. Western blotting experiment indicated compound 13e induced cell apoptosis via the extrinsic/intrinsic apoptosis pathway in MGC-803 cells. Therefore, compound 13e might be a valuable lead compound as antiproliferative agents and amino chalcone derivatives worth further effort to improve amino chalcone derivatives' potency. [ABSTRACT FROM AUTHOR]

Stimulator of interferon genes (STING) is an endoplasmic reticulum adaptor transmembrane protein that plays a pivotal role in innate immune system. STING agonists, such as endogenous cyclic dinucleotide (CDN) cyclic GMP-AMP (cGAMP), have been used in diverse clinical research for immunogenic tumor clearance, antiviral treatments and vaccine adjuvants. CDNs containing noncanonical mixed 3′-5′ and 2′-5′ phosphodiester linkages show higher potency in the activation of the STING pathway. In this study, a series of 2′3′-CDNs were designed and synthesized through a modified one-pot strategy. We then established a surface plasmon resonance (SPR)-based binding assay to quantify the binding affinities of synthesized CDNs for human STING, which requested a minuscule amount of sample without any pretreatment. Using this assay, we identified compound 8d (KD = 0.038 μM), a novel CDN that showed higher binding affinity with hSTING than cGAMP (KD = 0.543 μM). Cellular assays confirmed that 8d could trigger the expression of type I IFNs and other proinflammatory cytokines more robust than cGAMP. 8d also exhibited more resistant than cGAMP to enzymatic cleavage in vitro, indicating the successful improvement in drug availability. These findings provide guidelines for the design and structural optimization of CDNs as STING agonists. [ABSTRACT FROM AUTHOR]

As rate-limited enzyme of polyol pathway, aldose reductase (ALR2) is one of the key inhibitory targets for alleviating diabetic complications. To reduce the toxic side effects of the inhibitors and to decrease the level of oxidative stress, the inhibitory selectivity towards ALR2 against detoxicating aldehyde reductase (ALR1) and antioxidant activity are included in the design of multifunctional ALR2 inhibitors. Hydroxypyridinone derivatives were designed, synthesized and evaluated their inhibitory behavior and antioxidant activity. Notably, {2-[2-(3,4-dihydroxy-phenyl)-vinyl]-5-hydroxy-4-oxo-4H-pyridin-1-yl}-acetic acid (7l) was the most potent, with IC50 values of 0.789 μM. Moreover, 7l showed excellent selectivity towards ALR2 with selectivity index 25.23, which was much higher than that of eparlestat (17.37), the positive control. More significantly, 7l performed powerful antioxidative action. At a concentration of 1 μM, phenolic compounds 7l scavenged DPPH radical with an inhibitory rate of 41.48%, which was much higher than that of the well-known antioxidant Trolox, at 11.89%. Besides, 7l remarkably suppressed lipid peroxidation with a rate of 88.76% at a concentration of 100 μM. The binding mode derived from molecular docking proved that the derivatives were tightly bound to the activate site, suggesting strongly inhibitory action of derivatives against ALR2. Therefore, these results provided an achievement of multifunctional ALR2 inhibitors capable with potency for both selective ALR2 inhibition and as antioxidants. [ABSTRACT FROM AUTHOR]

Paecilomyces, a common saprobic filamentous fungus, not only plays an important role in biological control, but also has applications in medicine, food, and environmental protection. In this paper, 223 secondary metabolites and their bioactivities from 13 known species and various unidentified strains of Paecilomyces are reviewed. Their structures can be described as polyketide, terpenoid, peptide, alkaloid, quinone, pyrone, sterol, and fatty acid. They have been demonstrated varying biological activities, including antimicrobial, antitumor, insecticidal, antiplasmodial, antimalarial, nematicidal, herbicidal, and enzyme-inhibiting. This review provides a comprehensive overview of secondary metabolites and their biological activities from strains of Paecilomyces. [ABSTRACT FROM AUTHOR]

Andrographolide is a labdene diterpenoid with potential applications against a number of viruses, including the mosquito-transmitted dengue virus (DENV). In this study, we evaluated the anti-viral activity of three 14-aryloxy analogues (ZAD-1 to ZAD-3) of andrographolide against Zika virus (ZIKV) and DENV. Interestingly, one analogue, ZAD-1, showed better activity against both ZIKV and DENV than the parental andrographolide. A two-dimension (2D) proteomic analysis of human A549 cells treated with ZAD-1 compared to cells treated with andrographolide identified four differentially expressed proteins (heat shock 70 kDa protein 1 (HSPA1A), phosphoglycerate kinase 1 (PGK1), transketolase (TKT) and GTP-binding nuclear protein Ran (Ran)). Western blot analysis confirmed that ZAD-1 treatment downregulated expression of HSPA1A and upregulated expression of PGK1 as compared to andrographolide treatment. These results suggest that 14-aryloxy analogues of andrographolide have the potential for further development as anti-DENV and anti-ZIKV agents. [ABSTRACT FROM AUTHOR]