Photochemical α-selective radical ring-opening reactions of 1,3-disubstituted acyl bicyclobutanes with alkyl halides: modular access to functionalized cyclobutenes.

Although ring-opening reactions of bicyclobutanes bearing electron-withdrawing groups, typically with ß-selectivity, have evolved as a powerful platform for synthesis of cyclobutanes, their application in the synthesis of cyclobutenes remains underdeveloped. Here, a novel visible light induced α-selective radical ring-opening reaction of 1,3-disubstituted acyl bicyclobutanes with alkyl radical precursors for the synthesis of functionalized cyclobutenes is described. In particular, primary, secondary, and tertiary alkyl halides are all suitable substrates for this photocatalytic transformation, providing ready access to cyclobutenes with a single all-carbon quaternary center, or with two contiguous centers under mild reaction conditions.

Silver-Catalyzed Dearomative [2π+2σ] Cycloadditions of Indoles with Bicyclobutanes: Access to Indoline Fused Bicyclo[2.1.1]hexanes.

Bicyclo[2.1.1]hexanes (BCHs) are becoming ever more important in drug design and development as bridged scaffolds that provide underexplored chemical space, but are difficult to access. Here a silver-catalyzed dearomative [2π+2σ] cycloaddition strategy for the synthesis of indoline fused BCHs from N-unprotected indoles and bicyclobutane precursors is described. The strain-release dearomative cycloaddition operates under mild conditions, tolerating a wide range of functional groups. It is capable of forming BCHs with up to four contiguous quaternary carbon centers, achieving yields of up to 99 %. In addition, a scale-up experiment and the synthetic transformations of the cycloadducts further highlighted the synthetic utility.

C(sp2)-H cyclobutylation of hydroxyarenes enabled by silver-π-acid catalysis: diastereocontrolled synthesis of 1,3-difunctionalized cyclobutanes.

Ring-opening of bicyclo[1.1.0]butanes (BCBs) is emerging as a powerful strategy for 1,3-difunctionalized cyclobutane synthesis. However, reported radical strain-release reactions are typically plagued with diastereoselectivity issues. Herein, an atom-economic protocol for the highly chemo- and diastereoselective polar strain-release ring-opening of BCBs with hydroxyarenes catalyzed by a π-acid catalyst AgBF4 has been developed. The use of readily available starting materials, low catalyst loading, high selectivity (up to >98 : 2 d.r.), a broad substrate scope, ease of scale-up, and versatile functionalizations of the cyclobutane products make this approach very attractive for the synthesis of 1,1,3-trisubstituted cyclobutanes. Moreover, control experiments and theoretical calculations were performed to illustrate the reaction mechanism and selectivity.

Atom-economic and stereoselective catalytic synthesis of fully substituted enol esters/carbonates of amides in acyclic systems enabled by boron Lewis acid catalysis.

Carboacyloxylation of internal alkynes is emerging as a powerful and straightforward strategy for enol ester synthesis. However, the reported examples come with limitations, including the utilization of noble metal catalysts, the control of regio- and Z/E selectivity, and an application in the synthesis of enol carbonates. Herein, a boron Lewis acid-catalyzed intermolecular carboacyloxylation of ynamides with esters to access fully substituted acyclic enol esters in high yield with generally high Z/E selectivity (up to >96 : 4) is reported. Most importantly, readily available allylic carbonates are also compatible with this difunctionalization reaction, representing an atom-economic, catalytic and stereoselective protocol for the construction of acyclic ß,ß-disubstituted enol carbonates of amides for the first time. The application of the carboacyloxylation products to decarboxylative allylations provided a ready access to enantioenriched α-quaternary amides. Moreover, experimental studies and theoretical calculations were performed to illustrate the reaction mechanism and rationalize the stereochemistry.

Boron Lewis Acid Catalysis Enables the Direct Cyanation of Benzyl Alcohols by Means of Isonitrile as Cyanide Source.

The development of an efficient and straightforward method for cyanation of alcohols is of great value. However, the cyanation of alcohols always requires toxic cyanide sources. Herein, an unprecedented synthetic application of an isonitrile as a safer cyanide source in B(C6F5)3-catalyzed direct cyanation of alcohols is reported. With this approach, a wide range of valuable α-aryl nitriles was synthesized in good to excellent yields (up to 98%). The reaction can be scaled up and the practicability of this approach is further manifested in the synthesis of an anti-inflammatory drug, naproxen. Moreover, experimental studies were performed to illustrate the reaction mechanism.

SUMO1-modified DNA methyltransferase 1 induces DNA hypermethylation of VWC2 in the development of colorectal cancer.

Aberrant DNA methylation of genes is closely linked to many aspects of tumor development. This study focuses on the effect of DNA hypermethylation of von Willebrand factor C domain containing 2 (VWC2) on colorectal cancer (CRC) progression and the underpinning mechanism. According to data in the bioinformatic systems, VWC2 had the highest degree of DNA methylation in colonic adenocarcinoma, and it showed DNA hypermethylation in rectal adenocarcinoma as well. CRC and the para-tumorous tissues were collected from 86 patients. VWC2 was expressed at low levels in CRC samples and inversely correlated with tumor stage and tumor biomarker expression. DNA hypermethylation and reduced expression of VWC2 were also detected in CRC cell lines HCT-116 and HT29. VWC2 overexpression suppressed the malignant growth of cells in vitro and in vivo. Co-immunoprecipitation and western blot assays showed that small ubiquitin-like modifier 1 (SUMO1) mediated SUMOylation of DNA methyltransferase 1 (DNMT1) and strengthened its protein stability, which promoted DNA methylation and suppression of the VWC2 gene. In summary, this study demonstrates that SUMO1-mediated activation of DNMT1 induces DNA methylation and downregulation of VWC2 in CRC to augment cancer development.

Boron Lewis Acid Catalyzed Intermolecular trans-Hydroarylation of Ynamides with Hydroxyarenes.

An atom-economic protocol for the efficient and highly chemo- and stereoselective trans-hydroarylation of ynamides with hydroxyarenes catalyzed by B(C6F5)3 has been developed. Use of readily available starting materials, low catalyst loading, mild reaction conditions, a broad substrate scope, ease of scale-up, and versatile functionalizations of the enamide products make this approach very practical and attractive.

Ferroptosis: Opportunities and Challenges in Myocardial Ischemia-Reperfusion Injury.

Ferroptosis is a newly discovered form of regulated cell death dependent on iron and reactive oxygen species (ROS). It directly or indirectly affects the activity of glutathione peroxidases (GPXs) under the induction of small molecules, causing membrane lipid peroxidation due to redox imbalances and excessive ROS accumulation, damaging the integrity of cell membranes. Ferroptosis is mainly characterized by mitochondrial shrinkage, increased density of bilayer membranes, and the accumulation of lipid peroxidation. Myocardial ischemia-reperfusion injury (MIRI) is an unavoidable risk event for acute myocardial infarction. Ferroptosis is closely associated with MIRI, and this relationship is discussed in detail here. This review systematically summarizes the process of ferroptosis and the latest research progress on the role of ferroptosis in MIRI to provide new ideas for the prevention and treatment of MIRI.

miR-451-3p alleviates myocardial ischemia/reperfusion injury by inhibiting MAP1LC3B-mediated autophagy.

OBJECTIVE AND DESIGN: We aim to explore the molecular mechanism of myocardial ischemia-reperfusion injury (MIRI). METHODS: The H9C2 cells were cultured under hypoxia/reoxygenation (H/R) condition to induce myocardial injury in vitro. The expression of miR-451-3p and MAP1LC3B was detected by RT-qPCR. Dual-luciferase reporter assay and RNA pull-down assay were performed to examine the relationship between microRNA (miR)-451-3p and MAP1LC3B. CCK8 was used to test cell viability. The level of LDH and CK was evaluated via ELISA. Immunofluorescence assay and flow cytometry were applied to detect autophagy and apoptosis, respectively. Autophagy-related protein expressions were determined by western blotting. Furthermore, an in vivo rat model of MIRI was established by subjection to 30 min ischemia and subsequently 24 h reperfusion for validation of the role of miR-451-3p in regulating MIRI in vivo. RESULTS: miR-451-3p was down-regulated in MIRI, and miR-451-3p mimics transfection alleviated autophagy and apoptosis induced by MIRI. miR-451-3p could target MAP1LC3B directly. Co-transfection miR-451-3p mimics and pcDNA 3.1 MAP1LC3B curbed the protected effects of miR-451-3p mimics on MIRI. CONCLUSIONS: miR-451-3p played a protective role in MIRI via inhibiting MAP1LC3B-mediated autophagy, which may provide new molecular targets for the treatment of MIRI and further improves the clinical outcomes of heart diseases.

Immune Cell Infiltration as Signatures for the Diagnosis and Prognosis of Malignant Gynecological Tumors.

Background Malignant gynecological tumors are the main cause of cancer-related deaths in women worldwide and include uterine carcinosarcomas, endometrial cancer, cervical cancer, ovarian cancer, and breast cancer. This study aims to determine the association between immune cell infiltration and malignant gynecological tumors and construct signatures for diagnosis and prognosis. Methods We acquired malignant gynecological tumor RNA-seq transcriptome data from the TCGA database. Next, the "CIBERSORT" algorithm calculated the infiltration of 22 immune cells in malignant gynecological tumors. To construct diagnosis and prognosis signatures, step-wise regression and LASSO analyses were applied, and nomogram and immune subtypes were further identified. Results Notably, Immune cell infiltration plays a significant role in tumorigenesis and development. There are obvious differences in the distribution of immune cells in normal, and tumor tissues. Resting NK cells, M0 Macrophages, and M1 Macrophages participated in the construction of the diagnostic model, with an AUC value of 0.898. LASSO analyses identified a risk signature including T cells CD8, activated NK cells, Monocytes, M2 Macrophages, resting Mast cells, and Neutrophils, proving the prognostic value for the risk signature. We identified two subtypes according to consensus clustering, where immune subtype 3 presented the highest risk. Conclusion We identified diagnostic and prognostic signatures based on immune cell infiltration. Thus, this study provided a strong basis for the early diagnosis and effective treatment of malignant gynecological tumors.

Efficacy and Safety of a Combination of Shenmai Injection plus Chemotherapy for the Treatment of Lung Cancer: A Meta-Analysis.

OBJECTIVE: To perform a systematic evaluation of the efficacy and safety of combined treatment of Shenmai injection and chemotherapy for lung cancer. METHODS: A literature search for randomized controlled trials (RCTs) describing the treatment of lung cancer by Shenmai injection and chemotherapy or chemotherapy alone was performed using the PubMed, Cochrane Library, China National Knowledge Infrastructure (CNKI), Value In Paper (VIP), China BioMed, and Wanfang databases. The databases were searched for entries published before September 1, 2019. RESULTS: Thirty-seven RCTs, comprising a total of 2808 cases, were included in the present meta-analysis. Of these, 1428 cases were treated by Shenmai injection plus chemotherapy, and 1380 cases were treated only by chemotherapy. The results of meta-analysis showed that the combined treatment (Shenmai injection plus chemotherapy) increased the short-term efficacy of treatment (relative risk [RR] = 1.183, 95% confidence interval [CI] = 1.043-1.343, P < 0.01) and improved patients' quality of life (RR = 1.514, 95%CI = 1.211-1.891, P < 0.01) compared with chemotherapy alone. With regard to the adverse effects, the combined treatment markedly reduced the incidence of white blood cell (WBC) reduction (RR = 0.846, 95%CI = 0.760-0.941, P < 0.01), platelet reduction (RR = 0.462, 95% CI = 0.330-0.649, P < 0.01), and hemoglobin reduction (RR = 0.462, 95% CI = 0.330-0.649, P < 0.01) and alleviated drug-induced liver injury (RR = 0.677, 95%CI = 0.463-0.990, P < 0.05). However, it did not offer a significant protective effect (RR = 0.725, 95%CI = 0.358-1.468, P < 0.05). The effect of the combined treatment on the occurrence of vomiting was considerable (RR = 0.889, 95%CI = 0.794-0.996, P < 0.05), and the combined treatment markedly increased the immunity of patients with lung cancer. CONCLUSION: The combined treatment of Shenmai injection plus chemotherapy enhanced the short-term efficacy of chemotherapy, improved the patient quality of life, alleviated the adverse effects of chemotherapeutics, and increased the patient immunity. These results should be confirmed by large-scale, high-quality RCTs.

Frustrated nonsequential double ionization of Ar atoms in counter-rotating two-color circular laser fields.

We theoretically investigate the frustrated double ionization (FDI) of Ar atoms with counter-rotating two-color circular (CRTC) laser fields using the three-dimensional (3D) classical ensemble method. Our results show that the FDI probability depends upon the intensity ratio of the CRTC laser fields. The FDI event accompanied with the recollision excitation with subsequent ionization is prevalent and three pathways exist in FDI processes driven by CRTC laser fields. The momentum distribution of a recaptured electron at the ionization time after recollision indicates that the momentum being close to the vector potential is a necessary condition for FDI events to occur. In addition, the recaptured electron most probably transitions to a Rydberg state of which the quantum number is ten in the CRTC fields.

Safety and Efficacy of Ginkgo-Damole and Nitroglycerin or Sodium Nitroprusside on Hypertensive Cerebropathies: A Meta-Analysis.

OBJECTIVE: To systematically evaluate the safety and efficacy of ginko-damole combined with nitroglycerin or unitary sodium nitroprusside on hypertensive cerebropathy. METHODS: Four Chinese databases (VIP, CBM, Wanfang database, and CNKI database) and three English databases (Cochrane, PubMed, and EMBASE) were used to screen randomised controlled trials (RCTs) on treatments of hypertensive cerebropathy using both ginko-damole and nitroglycerin or unitary sodium nitroprusside. Outcomes included clinical effect, blood pressure after treatment, and adverse effects. These indicators were then analysed statistically using the RevMan 5.3 and Stata 12.0 software. RESULTS: Altogether, 16 RCTs including 1507 patients with hypertensive cerebropathy were included in the present meta-analysis, of which, 755 patients treated with combined ginko-damole and nitroglycerin were included in the observation group and 752 patients treated with sodium nitroprusside were included in the control group. The curative effect of the observation group was significantly better than that of the control group (RR: 1.115 [1.077, 1.155], p < 0.05). DBPs of the observation and control groups were both lower after treatment, and no significant difference was observed between the observation and control groups (MD: -1.072 [-2.578, 0.434], p > 0.05). SBPs in the observation group were significantly lower than those in the control group (MD: -2.842 [-5.222, -0.462], p < 0.05). The probability of adverse response in both groups did not differ significantly (RR: 0.752 [0.412, 1.374], p > 0.05). CONCLUSION: Compared with sodium nitroprusside, the combined ginkgo-damole and nitroglycerin could better control blood pressure in patients with hypertensive cerebropathy and showed enhanced clinical effects and improved safety. However, due to poor quality of the included studies, results of the present meta-analysis should be confirmed by more stringent RCTs.

Histone deacetylase HDAC4 promotes the proliferation and invasion of glioma cells.

Glioma is the most lethal type of primary brain tumor characterized by aggressiveness and a poor prognosis. Histone deacetylase 4 (HDAC4) is frequently dysregulated in human malignancies. However, its biological functions in the development of glioma are not fully understood. The present study aimed to evaluate HDAC4 expression in human glioma and to elucidate the mechanistic role of HDAC4 in glioma. The results suggested that HDAC4 was significantly upregulated in glioma tissues and a number of glioma cell lines compared with adjacent non-tumor tissues and the non-cancerous human glial cell line SVG p12, respectively (P<0.05). The proliferation, adenosine triphosphate (ATP) levels and invasion ability were substantially enhanced in U251 cells with HDAC4 overexpression, and suppressed in U251 cells with a knockdown of HDAC4 compared with that in U251 cells transfected with the negative control. Knockdown of HDAC4 resulted in cell cycle arrest at the G0/G1 phase and induced the increase of reactive oxygen species level in U251 cells. Furthermore, HDAC4 overexpression was revealed to substantially inhibit the expression of cyclin-dependent kinase (CDK) inhibitors p21 and p27, and the expression of E-cadherin and ß­catenin in glioma U251 cells. Knockdown of HDAC4 substantially promoted the expression of CDK1 and CDK2 and vimentin in glioma U251 cells. Mechanistically, the results of the present study demonstrated that HDAC4 displayed a significant upregulation in glioma, and promoted glioma cell proliferation and invasion mediated through the repression of p21, p27, E-cadherin and ß­catenin, and the potentiation of CDK1, CDK2 and vimentin. Altogether, the present study revealed that HDAC4 overexpression was central for the tumorigenesis of glioma, which may serve as a useful prognostic biomarker and potential therapeutic target for glioma.

Multiple recollisions in nonsequential double ionization by counter-rotating two-color circularly polarized laser fields.

With the three-dimensional (3D) classical ensemble method, we theoretically investigate the recollision dynamics in strong-field nonsequential double ionization (NSDI) of Ar by counter-rotating two-color circularly polarized laser fields. With the analysis of the NSDI trajectories, we find that not only multiple-recollision but also single-recollision processes occur in the double ionization events. Furthermore, the multiple-recollision and single-recollision processes both undergo the recollision-induced excitation with subsequent ionization (RESI) and recollision-induced ionization (RII). The angle between the momentum and the force of the laser field at the recollision moment can affect the times of the recollision.

Nonsequential double ionization of Mg from a doubly excited complex driven by circularly polarized laser field.

With the classical ensemble method, the correlated-electron dynamics of Mg atom from a doubly excited, transition Coulomb complex in few-cycle circularly polarized (CP) laser field at low laser intensity is theoretically investigated. The low energy transfer during the recollision process indicates that the two electrons cannot release directly, but it can pass through a doubly excited state, and then escape with the ionization time difference. The numerical results show that the feature of the sequential double ionization (SDI) can be observed in the nonsequential double ionization (NSDI) process. The SDI-like results demonstrate that the intermediate state has lost any memory of its formation dynamics. The distribution of the angle between the two release directions of the two electrons also depends on the ionization time difference. Finally, the influence of e-e Coulomb repulsion is discussed.

[Amelioration of myocardial ischemia/reperfusion injury by leptin pretreatment and ischemic preconditioning in mouse].

OBJECTIVE: To study the effects and role of leptin pretreatment and ischemic preconditioning (IPC) on the reduction of myocardial ischemia/reperfusion injury (MIRI) in mouse. METHODS: Thirty-six male C57BL/6 mice were randomized into five groups: (1)sham operation group (n=12); (2) brief ischemia/reperfusion (I/R) treatment group (n=6), in which the mice were subjected to three cycles of a 3-minute regional ischemia followed by a 5-minute reperfusion (I/R cycle); (3) MIRI group (n=6), in which MIRI was established in the mice by blocking anterior descending branch of left coronary artery for 30 minutes, followed by 120 minutes reperfusion; (4) IPC group (n=6), in which three I/R cycles were performed on the mice followed by the MIRI protocol; (5) leptin pretreatment group (leptin group, n=6), in which 50 microg/kg of leptin was injected intraperitoneally to the mice 30 minutes before myocardial ischemia. From 6 mice of the sham operation group and from the mice of brief I/R group, serum samples were collected at different time points (0, 5, 30 and 120 minutes) after reperfusion to measure changes in serum leptin level. From the rest of the mice, blood and heart samples were harvested at 120 minutes after reperfusion to analyze the myocardial function and infarct size, leptin, myeloperoxidase (MPO), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) levels. RESULTS: IPC procedure resulted in an increase in serum leptin level shortly after reperfusion. The leptin level increased significantly than that of sham operation group [(6.24+/-2.34) microg/L vs. (1.35+/-0.45) microg/L] at 5 minutes after I/R, and reached the peak value of (12.36+/-1.33) microg/L at 30 minutes after I/R. Then it gradually decreased to its original (0 minute after reperfusion) value [(1.96+/-1.33) microg/L] at 120 minutes after I/R. There was no difference compared with sham operation group [(1.16+/-0.25) microg/L, P>0.05]. Administration of leptin or IPC before MIRI significantly reduced infarct size [(11.50+/-2.26)%, (9.00+/-1.90)% vs. (37.00+/-2.53)%], the myocardial leptin levels [(8.36+/-3.42) microg/g, (6.71+/-2.03) microg/g vs. (15.51+/-3.92) microg/g], MPO [(17.10+/-3.95) microg/g, (13.33+/-2.88) microg/g vs. (30.83+/-4.06) microg/g], serum leptin levels [(15.03+/-1.87) microg/L, (11.85+/-0.72) microg/L vs. (29.55+/-2.31) microg/L], serum TNF-alpha [(35.10+/-10.12) ng/L, (27.04+/-5.18) ng/L vs. (81.34+/-14.20) ng/L], and IL-6 levels [(167.39+/-72.83) ng/L, (149.13+/-37.69) ng/L vs. (477.30+/-29.09) ng/L, all P<0.01]. CONCLUSION: Pretreatment using leptin results in preconditioning-like tolerance against infarction dysfunction. This cardiac protection effect is mediated, in part, via suppression of inflammation in preconditioned myocardium.

Metabolism of hibifolin by human intestinal bacteria.

Hibifolin, the highest-content bioactive flavonoid of the flowers of Abelmoschus manihot, was incubated with human intestinal bacteria, and four metabolites (1-4) were obtained from the incubated solution by chromatographic methods. The structures of the four metabolites were elucidated as gossypetin 8-O-beta-D-4''-deoxy- Delta(4'')-glucuropyranoside (1), gossypetin (2), quercetin (3), and 8-methoxy-quercetin (4), respectively, on the basis of UV, NMR, and MS data. Metabolite 1 was obtained as a new compound with a specific beta-D-4''-deoxy-Delta(4'')-glucuropyranosyl moiety, which was formed through a unique and novel metabolic pathway that has not been reported previously.