Domino Michael/Oxa-Michael Reactions of the Unsymmetric Double Michael Acceptor for Access to Bicyclic Furo[2,3-b]pyrrole.

By creating an unsymmetric double Michael acceptor 1, we were able to synthesize the nonaromatic-fused bicyclic furo[2,3-b]pyrrole nucleus using a domino Michael/oxa-Michael reaction. Adopting benzoyl acetonitrile 2d (CN as the electron-withdrawing group) as a substrate, we discovered a (DHQ)2AQN-catalyzed method for high diastereo- and enantioselectivity of those products. The reaction path has been determined by isolating the reaction intermediates, and density functional theory calculations support these findings. Beyond providing a synthetic approach, this work illustrated the compounds' possible use in antitumor activity.

TA-MSCs, TA-MSCs-EVs, MIF: their crosstalk in immunosuppressive tumor microenvironment.

As an important component of the immunosuppressive tumor microenvironment (TME), it has been established that mesenchymal stem cells (MSCs) promote the progression of tumor cells. MSCs can directly promote the proliferation, migration, and invasion of tumor cells via cytokines and chemokines, as well as promote tumor progression by regulating the functions of anti-tumor immune and immunosuppressive cells. MSCs-derived extracellular vesicles (MSCs-EVs) contain part of the plasma membrane and signaling factors from MSCs; therefore, they display similar effects on tumors in the immunosuppressive TME. The tumor-promoting role of macrophage migration inhibitory factor (MIF) in the immunosuppressive TME has also been revealed. Interestingly, MIF exerts similar effects to those of MSCs in the immunosuppressive TME. In this review, we summarized the main effects and related mechanisms of tumor-associated MSCs (TA-MSCs), TA-MSCs-EVs, and MIF on tumors, and described their relationships. On this basis, we hypothesized that TA-MSCs-EVs, the MIF axis, and TA-MSCs form a positive feedback loop with tumor cells, influencing the occurrence and development of tumors. The functions of these three factors in the TME may undergo dynamic changes with tumor growth and continuously affect tumor development. This provides a new idea for the targeted treatment of tumors with EVs carrying MIF inhibitors.

Application of engineered extracellular vesicles for targeted tumor therapy.

All cells, including prokaryotes and eukaryotes, could release extracellular vesicles (EVs). EVs contain many cellular components, including RNA, and surface proteins, and are essential for maintaining normal intercellular communication and homeostasis of the internal environment. EVs released from different tissues and cells exhibit excellent properties and functions (e.g., targeting specificity, regulatory ability, physical durability, and immunogenicity), rendering them a potential new option for drug delivery and precision therapy. EVs have been demonstrated to transport antitumor drugs for tumor therapy; additionally, EVs' contents and surface substance can be altered to improve their therapeutic efficacy in the clinic by boosting targeting potential and drug delivery effectiveness. EVs can regulate immune system function by affecting the tumor microenvironment, thereby inhibiting tumor progression. Co-delivery systems for EVs can be utilized to further improve the drug delivery efficiency of EVs, including hydrogels and liposomes. In this review, we discuss the isolation technologies of EVs, as well as engineering approaches to their modification. Moreover, we evaluate the therapeutic potential of EVs in tumors, including engineered extracellular vesicles and EVs' co-delivery systems.

Iron(III)-catalyzed α-cyanation and carbonylation with 2-pyridylacetonitrile: divergent synthesis of α-amino nitriles and tetrahydroisoquinolinones.

Iron-catalyzed oxidative synthesis of N-aryl-substituted tetrahydroisoquinolines (THIQs) toward tetrahydroisoquinoline-based derivatives is reported. A wide range of α-amino nitriles and tetrahydroisoquinolinones are synthesized in moderate to good yields. This approach involves a new organic nitrile source, a cheap iron catalyst under an oxygen atmosphere, and temperature-controlled divergent synthesis and features complete selectivity and operational simplicity.

Developing Push-Pull Hydroxylphenylpolyenylpyridinium Chromophores as Ratiometric Two-Photon Fluorescent Probes for Cellular and Intravital Imaging of Mitochondrial NQO1.

This work highlights the use of push-pull hydroxylphenylpolyenylpyridinium fluorophores coupled with trimethyl lock quinone to engineer the ratiometric two-photon probes for cellular and intravital imaging of mitochondrial NAD(P)H:quinone oxidoreductase 1 (NQO1), a critical antioxidant enzyme responsible for detoxifying quinones. As a typical representative, QBMP showed favorable binding with NQO1 with a Michaelis constant of 12.74 µM and exhibited a suite of superior properties, including rapid response (4 min), large Stokes shift (162 nm), ultralow detection limit (0.9 nM), favorable two-photon cross section for the released fluorophore (70.5 GM), and deep tissue penetration (225 µm) in fixed brain tissues. More importantly, this probe was successfully applied for distinguishing different NQO1-expressing cancer and normal cells, revealing decreased NQO1 activity in a cellular Parkinson's disease model, screening NQO1 inducers as neuroprotective agents, and imaging of NQO1 in live mouse brain.

Ce(iii)-catalyzed highly efficient synthesis of pyridyl benzamides from aminopyridines and nitroolefins without external oxidants.

An efficient synthesis of a variety of pyridyl benzamides from 2-aminopyridines and nitroolefins is described. This rare-earth-metal-catalyzed reaction provides the corresponding products with broad substrate scope in moderate to excellent yields, in the absence of additives and external oxidants. Water is used as the source of the carbonyl oxygen atom in pyridyl benzamides. Furthermore, 2-substituted oxazolo[4,5-b]pyridines are formed in good yields under the standard conditions when 2-aminopyridin-3-ols are used as the substrates.

Green and highly effective extraction of bioactive flavonoids from Fructus aurantii employing deep eutectic solvents-based ultrasonic-assisted extraction protocol.

In China, Jiang Fructus aurantii (JFA) has attracted increasing interest as a famous traditional herbal medicine and valuable economic food for its valuable medicinal and industrial properties. In the current work, contrasted with conventional extraction techniques, natural flavonoids from JFA (naringin and neohesperidin) were extracted with remarkable effectiveness utilizing a sustainable deep eutectic solvents combined ultrasonic-assisted extraction (DESs-UAE) protocol. The optimal extraction capacity can be achieved by mixing 30 % water with a molar ratio of 1:3 for choline chloride and ethylene glycol, as opposed to the classical extraction solvents of 95 % ethanol, methanol, and water. Moreover, the DESs-UAE extraction programs were also systematically optimized employing Box-Behnken design (BBD) trials, and the eventual findings suggested that the best parameters were a 27 % water content in DES, a 16 mL/g liquid-solid ratio, a 72 min extraction time, and a 62 °C extraction temperature, along with the corresponding greatest contents of NAR (48.18 mg/g) and NEO (34.50 mg/g), respectively. Notably, by comparison with the pre-optimization data, the optimized DES extraction efficiency of flavonoids is markedly higher. Thereafter, the characterization of the solvents before and after extraction, as well as the differences between the four extraction solvent extracts, were compared using the FT-IR analyses. Furthermore, SEM results suggested that the penetration and erosion abilities of the plant cell wall of DES-1 were stronger than those of the other three traditional solvents, thus allowing more release of flavonoid compounds. In conclusion, the present research develops a straightforward, sustainable, and exceedingly efficient approach for the extraction of bioactive flavonoids from JFA, which has the potential to facilitate the efficient acquisition of active ingredients from TCM.

The peripheral messenger RNA expression of glycogen synthase kinase-3ß genes in Alzheimer's disease patients: a preliminary study.

OBJECTIVE: To explore the peripheral leucocytic messenger RNA (mRNA) expression of glycogen synthase kinase-3ß (GSK-3ß) gene in Alzheimer's disease (AD) patients. METHODS: Using TaqMan relative quantitative real-time polymerase chain reaction, we analyzed leucocytic gene expression of GSK-3ß in 48 AD patients and 49 healthy controls. Clinical data of AD patients were also collected. RESULTS: The mRNA expression level of the GSK-3ß gene was significantly higher in the AD group (3.13±0.62) than in the normal group (2.77±0.77). Correlational analyses showed that the mRNA expression level of GSK-3ß gene in AD patients was associated with the age of onset (P=0.047), age (P=0.055), and Behavioral Pathology in Alzheimer's Disease Rating Scale total score (P=0.062) and subscores: aggressiveness score (P=0.073) and anxieties and phobias score (P=0.067). Through multivariate regression model, older age, higher anxieties and phobias score and aggressiveness score were associated with higher mRNA expression level of GSK-3ß gene. CONCLUSION: In AD patients, the mRNA expression level of the GSK-3ß gene is increased and may be related to age and behavioural pathology in AD.

[Effect of Lycium ruthenicum anthocyanins on atherosclerosis in mice].

OBJECTIVE: To study the effect of Lycium ruthenicum anthocyanins on atherosclerosis (AS) in mice. METHOD: Normal mice were taken as the control group, and hyperlipemia mice were divided into the model group, Lycium ruthenicum anthocyanins low, medium and high dose groups, and the simvastatin drug control group. After the oral administration, blood lipid indicators were detected by enzymatic analysis. The histomorphological changes in aortas, hearts and livers were observed, and liver-related indicators were determined by using hematoxylin-eosin (HE) staining. RESULT: Compared with the high-fat group, L. ruthenicum anthocyanins low, medium and high dose groups showed significant decrease in total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and atherosclerotic index (AI) (P < 0.05). However, high-density lipoprotein cholesterol (HDL-C) level showed a trend of higher than the model group. Liver's total antioxidant capacity (T-AOC), Glutathione peroxidase (GSH-PX), lipoprotein lipase (LPL) were significantly increased (P < 0.05), malondialdehyde (MDA) was markedly decreased (P < 0.01); the percentage of aortic plaque area of each anthocyanins dose group in the total area was significantly lower than the model group (P < 0.05); severity of aorta, heart and liver were significantly lighter than the high-fat group. But the media dose group was similar with the simvastatin group. CONCLUSION: L. ruthenicum anthocyanins can interfere the formation of AS, while lowering blood lipid levels in mice.

Base-promoted highly efficient synthesis of nitrile-substituted cyclopropanes via Michael-initiated ring closure.

A convenient and efficient annulation reaction has been developed for the general synthesis of dinitrile-substituted cyclopropanes in moderate to excellent yields. A variety of 2-arylacetonitriles and α-bromoennitriles were compatible under the standard conditions. The reaction was achieved through tandem Michael-type addition followed by intramolecular cyclization. The preliminary application of this method was confirmed by the synthesis of the 2,4-dioxo-3-azabicyclo[3.1.0]hexane scaffold.

Crosstalk among m6A RNA methylation, hypoxia and metabolic reprogramming in TME: from immunosuppressive microenvironment to clinical application.

The tumor microenvironment (TME), which is regulated by intrinsic oncogenic mechanisms and epigenetic modifications, has become a research hotspot in recent years. Characteristic features of TME include hypoxia, metabolic dysregulation, and immunosuppression. One of the most common RNA modifications, N6-methyladenosine (m6A) methylation, is widely involved in the regulation of physiological and pathological processes, including tumor development. Compelling evidence indicates that m6A methylation regulates transcription and protein expression through shearing, export, translation, and processing, thereby participating in the dynamic evolution of TME. Specifically, m6A methylation-mediated adaptation to hypoxia, metabolic dysregulation, and phenotypic shift of immune cells synergistically promote the formation of an immunosuppressive TME that supports tumor proliferation and metastasis. In this review, we have focused on the involvement of m6A methylation in the dynamic evolution of tumor-adaptive TME and described the detailed mechanisms linking m6A methylation to change in tumor cell biological functions. In view of the collective data, we advocate treating TME as a complete ecosystem in which components crosstalk with each other to synergistically achieve tumor adaptive changes. Finally, we describe the potential utility of m6A methylation-targeted therapies and tumor immunotherapy in clinical applications and the challenges faced, with the aim of advancing m6A methylation research.

Mesenchymal stem cell-derived exosome: A tumor regulator and carrier for targeted tumor therapy.

Mesenchymal stem cells (MSCs) are multipotent stromal cells that have the ability to differentiate into multiple cell types. Several studies have shown that exosomes secreted by MSCs (MSCs-Exo) play an important role in tumor growth, angiogenesis, invasion, and drug resistance. However, contradictory results have suggested that MSCs-Exo can also suppress tumors through specific mechanisms, such as regulating immune responses and intercellular signaling. Consequently, the relationship between MSCs-Exo and tumors remains controversial. However, it is undeniable that exosomes, as natural vesicles, can be excellent drug carriers and show promise for application in targeted tumor therapy. Here, we review the current knowledge regarding the involvement of MSCs-Exo in tumor progression and their potential as drug delivery systems in targeted therapy. We argue that MSCs-Exo can be used as safe carriers of antitumor drugs.

Independent risk factors for true malignancy in atypical cytologic diagnostic category in EUS-FNA/FNB of the pancreas: A novel prediction model.

Background and Objects: An atypical cytologic diagnosis arises from inflammation or early neoplastic process. It is commonly found in EUS-guided fine-needle aspiration/biopsy (EUS-FNA/FNB) tissue sampling of pancreatic malignancies. The aims of this study were to evaluate the diagnostic performance of EUS-FNA/FNB in patients with cytologic diagnosis of atypical cells and to develop a prediction model for malignant tumors of the pancreas in the atypical cytologic diagnostic category. Methods: Two hundred and twenty-six patients in the atypical cytologic diagnostic category were analyzed. Multivariate logistic regression analyses were performed to determine predictive factors for pancreatic malignancies. The final diagnoses were confirmed by repeat biopsy; surgical pathology, or clinical follow-up for at least 6 months. Results: The atypical cytologic diagnosis using EUS-FNA/FNB was associated with an absolute risk of malignancy (82.3%). Multivariate logistic regression analyses revealed that older age, long axis of the mass, and increased carbohydrate antigen 19-9 (CA19-9) were independent risk factors for true malignant pancreatic tumors among patients in the atypical cytologic diagnostic category. The calibration curve had a slope of 0.96, and a regression coefficient (R2) of 0.91. The area under the receiver operating characteristic curve of the validation group was 0.803. Conclusions: Atypical lesions of EUS-FNA/FNB have a higher risk of malignancy. Older age, the long axis of the mass, and elevated serum CA19-9 level were identified as independent risk factors for true malignant pancreatic tumors among patients in the atypical cytologic diagnostic category.

Antioxidant and antiproliferative activities of hydroxyl-substituted Schiff bases.

Eight hydroxyl-substituted Schiff bases with the different number and position of hydroxyl group on the two asymmetric aromatic rings (A and B rings) were prepared by the reaction between the corresponding aromatic aldehyde and aniline. Their antioxidant effects against the stable galvinoxyl radical (GO(.)) in ethyl acetate and methanol, and 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH)-induced DNA strand breakage, and their antiproliferative effects on human hepatoma HepG2 cells, were investigated. Structure-activity relationship analysis demonstrates that o-dihydroxyl groups on the aromatic A ring and 4-hydroxyl group attached to the aromatic B ring contribute critically to the antioxidant and antiproliferative activities.

Antioxidant activity of alpha-pyridoin and its derivatives: possible mechanism.

alpha-Pyridoin (1, 1,2-di(2-pyridyl)-1,2-ethenediol) is a unique enediol antioxidant. To explore the detailed antioxidant mechanism of alpha-pyridoin, we synthesized alpha-pyridoin and its 5,5'- or 6,6'-bis-substituted derivatives (2-7) and compared their capacities to scavenge galvinoxyl radical (GO*) and protect human red blood cells (RBCs) from oxidative haemolysis. It was found that the compounds (5 and 6) with a methyl or methoxy group at the 5-position exhibit significantly higher GO*-scavenging and anti-haemolysis activities than other derivatives and vitamin C. Kinetic analysis of the GO*-scavenging reaction and the effect of added base on the reaction rate revealed that in ethyl acetate, the reaction occurs primarily by the direct hydrogen atom transfer (HAT mechanism). However, in ethanol that supports ionization, the kinetics of the process is mostly governed by sequential proton loss electron transfer (SPLET mechanism).

[Association of cyclic adenosine monophosphate response element-binding protein gene and major depressive disorder].

OBJECTIVE: To investigate the association between single nucleotide polymorphisms (SNPs) in cyclic adenosine monophosphate response element-binding protein(CREB1) gene and major depressive disorder (MDD). METHODS: We recruited 105 parent-offspring trios of Chinese descent, extracted whole blood genomic DNA, and genotyped the SNPs in rs10932201 and rs6740584 loci. Single-marker transmission disequilibrium test (TDT), pairwise SNP linkage disequilibrium(LD) and haplotype-based TDT were performed. RESULTS: No significant association with MDD was observed for SNPs rs10932201 and rs6740584 (P=0.1004 and P=0.4986). However, there was strong positive association between the rs10932201-rs6740584 haplotype and MDD (P=0.00003241), and both haplotypes of A-C and A-T were significantly associated with MDD (P=0.020 and P=0.00022). CONCLUSION: The rs10932201-rs6740584 haplotype of the CREB1 gene may play an important role in the pathogenesis of MDD.

Hydroxycinnamic acids as DNA-cleaving agents in the presence of Cu(II) ions: mechanism, structure-activity relationship, and biological implications.

The effectiveness of hydroxycinnamic acids (HCAs), that is, caffeic acid (CaA), chlorogenic acid (ChA), sinapic acid (SA), ferulic acid (FA), 3-hydroxycinnamic acid (3-HCA), and 4-hydroxycinnamic acid (4-HCA), as pBR322 plasmid DNA-cleaving agents in the presence of Cu(II) ions was investigated. Compounds bearing o-hydroxy or 3,5-dimethoxy groups on phenolic rings (CaA, SA, and ChA) were remarkably more effective at causing DNA damage than the compounds bearing no such groups; furthermore, CaA was the most active among the HCAs examined. The involvement of reactive oxygen species (ROS) and Cu(I) ions in the DNA damage was affirmed by the inhibition of the DNA breakage by using specific scavengers of ROS and a Cu(I) chelator. The interaction between CaA and Cu(II) ions and the influence of ethylenediaminetetraacetic acid (EDTA), the solvent, and pH value on the interaction were also studied to help elucidate the detailed prooxidant mechanism by using UV/Vis spectroscopic analysis. On the basis of these observations, it is proposed that it is the CaA phenolate anion, instead of the parent molecule, that chelates with the Cu(II) ion as a bidentate ligand, hence facilitating the intramolecular electron transfer to form the corresponding CaA semiquinone radical intermediate. The latter undergoes a second electron transfer with oxygen to form the corresponding o-quinone and a superoxide, which play a pivotal role in the DNA damage. The intermediacy of the semiquinone radical was supported by isolation of its dimer from the Cu(II)-mediated oxidation products. Intriguingly, CaA was also the most cytotoxic compound among the HCAs toward human promyelocytic leukemia (HL-60) cell proliferation. Addition of exogenous Cu(II) ions resulted in an effect dichotomy on cell viability depending on the concentration of CaA; that is, low concentrations of CaA enhanced the cell viability and, conversely, high concentrations of CaA almost completely inhibited the cell proliferation. On the other hand, when superoxide dismutase was added before, the two stimulation effects of exogenous Cu(II) ions were significantly ameliorated, thus clearly indicating that the oxidative-stress level regulates cell proliferation and death. These findings provide direct evidence for the antioxidant/prooxidant mechanism of cancer chemoprevention.

Radical-scavenging activity and mechanism of resveratrol-oriented analogues: influence of the solvent, radical, and substitution.

Resveratrol (3,5,4'-trihydroxy-trans-stilbene, 3,5,4'-THS) is a well-known natural antioxidant and cancer chemopreventive agent that has attracted much interest in the past decade. To find a more active antioxidant and investigate the antioxidative mechanism with resveratrol as the lead compound, we synthesized 3,5-dihydroxy-trans-stilbene (3,5-DHS), 4-hydroxy-trans-stilbene (4-HS) 3,4-dihydroxy-trans-stilbene (3,4-DHS), 4,4'-dihydroxy-trans-stilbene (4,4'-DHS), 4-hydroxy-3-methoxy-trans-stilbene (3-MeO-4-HS), 4-hydroxy-4'-methoxy-trans-stilbene (4'-MeO-4-HS), 4-hydroxy-4'-methyl-trans-stilbene (4'-Me-4-HS), 4-hydroxy-4'-nitro-trans-stilbene (4'-NO(2)-4-HS), and 4-hydroxy-4'-trifluoromethyl-trans-stilbene (4'-CF(3)-4-HS). The radical-scavenging activity and detailed mechanism of resveratrol and its analogues (ArOHs) were investigated by the reaction kinetics with galvinoxyl (GO(*)) and 2,2-diphenyl-1-picrylhydrazyl (DPPH(*)) radicals in ethanol and ethyl acetate at 25 degrees C, using UV-vis spectroscopy. It was found that the reaction rates increase with increasing the electron-rich environment in the molecules, and the compound bearing o-dihydroxyl groups (3,4-DHS) is the most reactive one among the examined resveratrol analogues. The effect of added acetic acid on the measured rate constant for GO(*)-scavenging reaction reveals that in ethanol that supports ionization solvent besides hydrogen atom transfer (HAT), the kinetics of the process is partially governed by sequential proton loss electron transfer (SPLET). In contrast to GO(*), DPPH(*) has a relatively high reduction potential and therefore enhances the proportion of SPLET in ethanol. The relatively low rate constants for the reactions of ArOHs with GO(*) or DPPH(*) in ethyl acetate compared with the rate constants in ethanol prove that in ethyl acetate these reactions occur primarily by the HAT mechanism. The contribution of SPLET and HAT mechanism depends on the ability of the solvent to ionize ArOH and the reduction potential of the free radical involved. Furthermore, the fate of the ArOH-derived radicals, i.e., the phenoxyl radicals, was investigated by the oxidative product analysis of ArOHs and GO(*) in ethanol. The major products were dihydrofuran dimers in the case of resveratrol, 4,4'-DHS, and 4-HS and a dioxane-like dimer in the case of 3,4-DHS. It is suggested from the oxidative products of these ArOHs that the hydroxyl group at the 4-position is much easier to subject to oxidation than other hydroxyl groups, and the dioxane-like dimer is formed via an o-quinone intermediate.

4,4'-Dihydroxy-trans-stilbene, a resveratrol analogue, exhibited enhanced antioxidant activity and cytotoxicity.

Resveratrol (3,5,4'-trans-trihydroxystibene) is a natural phytoalexin present in grapes and red wine, which possesses a variety of biological activities including antioxidant activity. In order to find more active antioxidant with resveratrol as the lead compound we synthesized 4,4'-dihydroxy-trans-stilbene (4,4'-DHS). The antioxidant activities of resveratrol and 4,4'-DHS were evaluated by the reaction kinetics with galvinoxyl radical or Cu(II) ions, and the inhibition effects against free-radical-induced peroxidation of human erythrocyte ghosts. It was found that 4,4'-DHS exhibits remarkably higher antioxidant activity than resveratrol. The oxidative products of resveratrol and 4,4'-DHS in the presence of Cu(II) in acetonitrile were identified as the dihydrofuran dimers by spectroscopic method, and the antioxidant mechanism for 4,4'-DHS was proposed. In addition, 4,4'-DHS exhibits remarkably higher cytotoxicity against human promyelocytic leukemia (HL-60) cells than resveratrol.

Family-based association study between brain-derived neurotrophic factor gene and major depressive disorder of Chinese descent.

The genetic pathogenesis of major depressive disorder (MDD) has not been elucidated. It has been proposed that brain-derived neurotrophic factor (BDNF), as a member of the neurotrophin family, may be involved in the etiology and antidepressant response of MDD. The present study investigated the possible presence of an association between the BDNF gene and MDD. Single-marker transmission disequilibrium test (TDT), pairwise-SNP linkage disequilibrium (LD) and haplotype-based TDT analyses were performed on single nucleotide polymorphisms (SNPs) rs6265, rs10835210 and rs2030324 in 105 Chinese trios. No significant associations with MDD were demonstrated for three SNPs. Pairwise LD analysis revealed substantial LD among three SNPs. Multiple-marker TDT analysis indicated that there was no association between the haplotypes from rs6265-rs10835210-rs2030324 and MDD. The statistical power of the present study was calculated so we had an idea what kind of effects could be identified. We conclude that SNPs rs6265, rs10835210 and rs2030324 of the BDNF gene are unlikely to play a critical role in the pathogenesis of MDD.