Aryl-to-Vinyl 1,4-Nickel Migration/Reductive Cross-Coupling Reaction for the Stereoselective Synthesis of Multisubstituted Olefins.

The aryl-to-vinyl nickel 1,4-migration (1,4-Ni migration) reaction has been reported for the first time. The generated alkenyl Ni species undergo a reductive coupling reaction with unactivated brominated alkanes affording a series of trisubstituted olefins. This tandem reaction exhibits mild conditions, a broad substrate scope, high regioselectivity, and excellent Z/E stereoselectivity. A series of controlled experiments have shown that the critical 1,4-Ni migration process is reversible. In addition, the alkenyl nickel intermediates obtained after migration are highly Z/E stereoselective and do not undergo Z/E isomerization. The obtained trace isomerization products are caused by the instability of the product.

Photoredox-catalyzed redox-neutral difluoroalkylation to construct perfluoroketones with difluoroenoxysilanes.

A mild and facile approach to construct various perfluoroketones via photo-catalyzed difluoroalkylation of difluoroenoxysilanes is developed. The reaction includes a strategy of combination of two fluorine-containing functional groups, which confers the reaction with characteristics like high efficiency, mild conditions, and broad scope. A variety of fluoroalkyl halides including perfluoroalkyl iodides, bromo difluoro esters and amides can be employed as radical precursors. Control experiments indicate that a single-electron transfer pathway may be involved in the reaction.

Thermal ablation versus hepatic resection for the treatment of liver metastases from gastrointestinal stromal tumors: a retrospective study.

Objective: The study aimed to compare effectiveness and safety of thermal ablation and hepatic resection in patients with liver metastases of gastrointestinal stromal tumors (GISTs).Method: A total of 55 patients (27 in the ablation group and 28 in the surgery group) with liver metastases were included. Overall survival (OS) and progression-free survival (PFS) were assessed with Kaplan-Meier's survival estimate curves. Univariate and multivariate regression analyses were carried out to identify potential prognostic factors.Results: The median OS was 102.0 months in the ablation group and 117.0 months in the surgery group (p = .875). The 1-, 3- and 5-year OS rates were 100%, 88.9% and 74.1% in the ablation group and 92.8%, 82.1% and 78.6% in the surgery group, respectively. The 1-, 3- and 5-year PFS rates were 48.1%, 25.9% and 18.5% in the ablation group and 67.8%, 64.3% and 64.3% in the surgery group, respectively. Multivariate analysis showed that preoperative tyrosine kinase inhibitor (TKI) treatment (progressive disease, PD) (HR, 13.985; 95% CI, 1.791-109.187; p = .012) was the only significant independent prognostic factor for OS. Tumor number (HR, 1.318; 95% CI, 1.021-1.702; p = .034) was identified as an independent predictor for PFS in multivariate analysis. There were fewer postoperative complications (18.5% vs. 78.6%, p = .001) and shorter lengths of hospital stay (8.0 vs. 16.5 days, p = .001) in the ablation group.Conclusion: Compared with resection, thermal ablation offered comparable OS for liver metastases of GISTs. Furthermore, thermal ablation had the advantages of fewer complications and shorter lengths of hospital stay.

Repression of the miR-17-92 cluster by p53 has an important function in hypoxia-induced apoptosis.

We here report that miR-17-92 cluster is a novel target for p53-mediated transcriptional repression under hypoxia. We found the expression levels of miR-17-92 cluster were reduced in hypoxia-treated cells containing wild-type p53, but were unchanged in hypoxia-treated p53-deficient cells. The repression of miR-17-92 cluster under hypoxia is independent of c-Myc. Luciferase reporter assays mapped the region responding to p53-mediated repression to a p53-binding site in the proximal region of the miR-17-92 promoter. Chromatin immunoprecipitation (ChIP), Re-ChIP and gel retardation assays revealed that the binding sites for p53- and the TATA-binding protein (TBP) overlap within the miR-17-92 promoter; these proteins were found to compete for binding. Finally, we show that pri-miR-17-92 expression correlated well with p53 status in colorectal carcinomas. Over-express miR-17-92 cluster markedly inhibits hypoxia-induced apoptosis, whereas blocked miR-17-5p and miR-20a sensitize the cells to hypoxia-induced apoptosis. These data indicated that p53-mediated repression of miR-17-92 expression likely has an important function in hypoxia-induced apoptosis, and thus further our understanding of the tumour suppressive function of p53.

CHD1 deletion stabilizes HIF1α to promote angiogenesis and glycolysis in prostate cancer.

Chromodomain-helicase-DNA-binding protein 1 (CHD1) deletion is among the most common mutations in prostate cancer (PCa), but its role remains unclear. In this study, RNA sequencing was conducted in PCa cells after clustered regularly interspaced palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9)-based CHD1 knockout. Gene set enrichment analysis (GSEA) indicated upregulation of hypoxia-related pathways. A subsequent study confirmed that CHD1 deletion significantly upregulated hypoxia-inducible factor 1α (HIF1α) expression. Mechanistic investigation revealed that CHD1 deletion upregulated HIF1α by transcriptionally downregulating prolyl hydroxylase domain protein 2 (PHD2), a prolyl hydroxylase catalyzing the hydroxylation of HIF1α and thus promoting its degradation by the E3 ligase von Hippel-Lindau tumor suppressor (VHL). Functional analysis showed that CHD1 deletion promoted angiogenesis and glycolysis, possibly through HIF1α target genes. Taken together, these findings indicate that CHD1 deletion enhances HIF1α expression through PHD2 downregulation and therefore promotes angiogenesis and metabolic reprogramming in PCa.

Long noncoding RNA high expression in hepatocellular carcinoma facilitates tumor growth through enhancer of zeste homolog 2 in humans.

UNLABELLED: In recent years, long noncoding RNAs (lncRNAs) have been shown to have critical regulatory roles in cancer biology. However, the contributions of lncRNAs to hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) remain largely unknown. Differentially expressed lncRNAs between HBV-related HCC and paired peritumoral tissues were identified by microarray and validated using quantitative real-time polymerase chain reaction. Liver samples from patients with HBV-related HCC were analyzed for levels of a specific differentially expressed lncRNA High Expression In HCC (termed lncRNA-HEIH); data were compared with survival data using the Kaplan-Meier method and compared between groups by the log-rank test. The effects of lncRNA-HEIH were assessed by silencing and overexpressing the lncRNA in vitro and in vivo. The expression level of lncRNA-HEIH in HBV-related HCC is significantly associated with recurrence and is an independent prognostic factor for survival. We also found that lncRNA-HEIH plays a key role in G(0) /G(1) arrest, and further demonstrated that lncRNA-HEIH was associated with enhancer of zeste homolog 2 (EZH2) and that this association was required for the repression of EZH2 target genes. CONCLUSIONS: Together, these results indicate that lncRNA-HEIH is an oncogenic lncRNA that promotes tumor progression and leads us to propose that lncRNAs may serve as key regulatory hubs in HCC progression.

[Diagnostic value of enhanced computed tomography plus vascular endothelial growth factor C expression in hilar and mediastinal lymph node metastasis of non-small cell lung cancer].

OBJECTIVE: To explore the diagnostic value of preoperative enhanced computed tomography (CT) plus vascular endothelial growth factor C (VEGF-C) expression in hilar and mediastinal lymph nodes metastasis of non-small cell lung cancer. METHODS: A total of 87 patients with non-small cell lung cancer (NSCLC) received preoperative chest enhanced CT scans and underwent standard radical operation and systematic lymph node dissection. Pathologic examination was selected as the gold standard to determine lymph node metastasis. The immunohistochemical method was used to detect the expression of VEGF-C. The predicting values of chest enhanced CT, VEGF-C expression and their combination for the diagnosis of hilar and mediastinal lymph nodes metastasis were evaluated through comparing the sensitivity, specificity and accuracy. RESULTS: The sensitivity of CT scan was 75.0%, specificity 59.6% and accuracy 66.7%. The positive expression rate of VEGF-C was 78.2% (68/87) and strong positive rate 13.8% (12/87). The sensitivity of VEGF-C was 97.5%, specificity 38.3% and accuracy 65.5%. The combination of CT and VEGF-C had a better accuracy (74.7%) and the sensitivity and specificity were 80.0% and 70.2% respectively. CONCLUSION: Compared with CT scan or VEGF-C expression alone, the combination of CT and VEGF-C improves the specificity and accuracy of diagnosing lymph nodes metastasis in NSCLC. If this combination method is employed before therapy, the accuracy of clinical nodal staging may be enhanced.

[Diagnostic accuracy research of needle puncture biopsy during operation for pulmonary single nodules].

OBJECTIVE: To investigate the diagnostic accuracy of needle puncture biopsy and pathological examination of frozen during operation for pulmonary nodules, and whether this diagnostic method can replace tumor resection examination. METHODS: Totally 50 patients (28 males and 22 females, average age was 59 years) who had the single nodule after imaging examination without any pathological diagnostic from January to October 2010 were selected in this research work. During open operation or video assisted thoracic surgery, needle (14 G model) was used to puncture biopsy for pathological examination of frozen. All the adverse events during puncture biopsy would be recorded. The resection specimens would be accepted paraffin pathological examination. The relationship between puncture frozen pathological and paraffin pathological examination was analyzed. RESULTS: All tumor sizes were ranged from 1.0 cm × 0.6 cm to 5.6 cm × 9.0 cm. The paraffin pathological examination after operation as the golden standard, there were 7 cases of benign tumor and 43 cases of malignant tumor. The diagnostic sensitivity of puncture biopsy was 90.7%, the specificity was 100%, the positive predictive value was 100% and the negative predictive value was 63.6%. There were 11 cases of benign tumor diagnosed by needle puncture biopsy, among which 4 cases were proved as malignant tumor by paraffin pathology, and the false negative rate was 9.3%. The main risk of puncture biopsy was bleeding after puncture immediately, and the rate was 4.0% (2/50). CONCLUSIONS: The puncture biopsy during operation had a high specificity for malignant lung tumor, and there was a certain false negative rate for benign tumor. Puncture biopsy and pathological examination of frozen tissue can replace tumor section biopsy in a way.

Three-Component Ru-Catalyzed Regioselective Alkylarylation of Vinylarenes via Meta-Selective C(sp2)-H Bond Functionalization.

We report a novel Ru-catalyzed regioselective alkylarylation of vinylarenes with alkyl halides and arenes via meta-C(sp2)-H bond functionalization to construct 1,1-diarylalkanes that generally show bioactivity. In this transformation, a wide spectrum of primary, secondary, and tertiary alkyl halides and electronically varied arenes was well-tolerated. This reaction is characterized by its exquisite regioselectivity of vinylarenes, unique meta-C(sp2)-H selectivity, and redox-neutral conditions. The mechanism presented was supported by radical probes and kinetic isotope effect studies.

Visible-Light-Driven [3 + 2]/[4 + 2] Annulation Reactions of Alkenes with N-Aminopyridinium Salts.

The annulation reactions of benzoamidyl radicals with alkenes were realized under visible light irradiation with fac-Ir(ppy)3 as catalyst and N-aminopyridinium salts as benzoamidyl radical precursors. The reaction can deliver two distinct types of products: in the case of vinyl arenes, [3 + 2] annulation product dihydrooxazoles were yielded exclusively; when alkyl-substituted alkenes were used, on the other hand, it afforded [4 + 2] annulation product dihydroisoquinolinones. Factors determining the reaction consequence were elucidated by DFT calculations.

Site-selective coupling of remote C(sp3)-H/meta-C(sp2)-H bonds enabled by Ru/photoredox dual catalysis and mechanistic studies.

Construction of C(sp2)-C(sp3) bonds via regioselective coupling of C(sp2)-H/C(sp3)-H bonds is challenging due to the low reactivity and regioselectivity of C-H bonds. Here, a novel photoinduced Ru/photocatalyst-cocatalyzed regioselective cross-dehydrogenative coupling of dual remote C-H bonds, including inert γ-C(sp3)-H bonds in amides and meta-C(sp2)-H bonds in arenes, to construct meta-alkylated arenes has been accomplished. This metallaphotoredox-enabled site-selective coupling between remote inert C(sp3)-H bonds and meta-C(sp2)-H bonds is characterized by its unique site-selectivity, redox-neutral conditions, broad substrate scope and wide use of late-stage functionalization of bioactive molecules. Moreover, this reaction represents a novel case of regioselective cross-dehydrogenative coupling of unactivated alkanes and arenes via a new catalytic process and provides a new strategy for meta-functionalized arenes under mild reaction conditions. Density functional theory (DFT) calculations and control experiments explained the site-selectivity and the detailed mechanism of this reaction.

Visible-Light-Mediated Decarboxylative Radical Addition Bifunctionalization Cascade for the Production of 1,4-Amino Alcohols.

A photocatalytic decarboxylative radical addition bifunctionalization cascade for the synthesis of functionalized alcohols is described. The catalytic cycle is completed through single-electron transfer. The advantages of this reaction are the commercially available materials, wide functional group compatibility, and mild conditions. Notably, some amino acids and bioactive carboxylic acids can provide corresponding products in moderate to good yields, reflecting the potential value in drug development.

Copper-Catalyzed Radical Aryl Migration Approach for the Preparation of Cyanoalkylsulfonylated Oxindoles/Cyanoalkyl Amides.

A copper-catalyzed radical cross-coupling of oxime esters and activated alkenes is accomplished for the synthesis of cyanoalkylsulfonylated oxindoles and cyanoalkyl amides via an aryl migration strategy. Specifically, the subsequent mechanism research indicates that the unique desulfonylation and sulfone addition processes were involved in the transformation. This transformation is identified as having good functional group applicability with two different quaternary stereocenter in a regioselective manner, which is controlled by the substituent group of the nitrogen.

Cu-Catalyzed Direct C-H Alkylation of Polyfluoroarenes via Remote C(sp3)-H Functionalization in Carboxamides.

A novel dehydrogenative coupling reaction of N-fluorocarboxamides with polyfluoroarenes forming C(sp2)-C(sp3) bonds enabled by copper catalysis has been accomplished. N-Fluorocarboxamides are postulated to undergo copper-mediated dehydrogenative cross-coupling reaction with electron-deficient polyfluoroarenes via a radical pathway. Benzylic C-H bonds and aliphatic C-H bonds in N-fluorocarboxamides could proceed smoothly and demonstrated excellent regioselectivity. The detailed mechanism presented is supported by control experiments and density functional theory calculations.

[Role of pulmonary segmental and sub-segmental lymph nodes in pathological staging of lung cancer].

OBJECTIVE: To investigate the metastatic rate of segmental and/or sub-segmental lymph nodes and their roles in pathological staging after a major pulmonary resection. METHODS: This prospective study recruited 90 cases of pulmonary resection performed at our department from February 2007 to February 2008. Hilar lymph nodes (No. 10), interlobar nodes (No. 11), lobar nodes (No. 12), segmental nodes (No. 13) and subsegmental nodes (No. 14) were resected and their clinic data analyzed. RESULTS: (1) The median number of total lymph nodes harvested, mediastinal nodes, nodes from No. 10-14 and nodes from No. 13-14 were 29 (11-50), 17 (6-35), 12 (2-26) and 4 (1-17) respectively. Lymph node metastatic rate from No.10, No. 11, No. 12, No. 13 + 14 were 12.2%, 6.7%, 23.3% and 38.9% respectively. (2) Forty-two cases of N0 and 27 cases of N1 were diagnosed in this group. The N1 subgroup included 12 cases of No. 13-14 metastasis solely and 15 cases of No. 10-12 and No. 13-14 metastasis simultaneously. If an analysis of No. 13-14 was omitted, the diagnostic accuracy of N0 could only reach 77.8% and 44.4% cases would be under-staged from N1. (3) In 33 cases of peripheral lung cancers smaller than 3 cm in diameter, 12.1% of metastatic lymph nodes from No.12-13 would be left in the original place if a segmental resection was performed. Similarly, 18.2% of metastatic lymph nodes could be neglected for wedge resection cases. CONCLUSION: Metastasis to segmental or subsegmental lymph nodes accounts for a large part of lung cancer patients. Therefore an analysis of these nodes can improve the accuracy of pathological staging. Secondly, limited pulmonary resection needs to follow a strict indication in consideration of the potential metastasis to segmental or subsegmental lymph nodes in peripheral small lung cancers.

Visible-Light-Mediated Trifluoromethylation/Benzylation of Styrenes Catalyzed by 4-CzIPN.

Difunctionalization of alkenes is a valuable tool for the synthesis of complicated compounds from simple precursors. Herein, a feasible method for the construction of ß-trifluoromethyl-α-substituted alcohols under visible-light-induced metal-free conditions is described. This catalytic system exhibits mild reaction conditions and good compatibility of functional groups. Trifluoromethyl and alcohols are valuable structural motifs due to their unique biological properties, and this work shows the potential application in the realm of pharmacy and organic synthesis.

Visible-Light-Induced Pd-Catalyzed Radical Strategy for Constructing C-Vinyl Glycosides.

A novel visible-light-induced palladium-catalyzed Heck reaction for bromine sugars and aryl olefins with high regio- and stereochemistry selectivity for the preparation of C-glycosyl styrene is described. This reaction takes place in one step at room temperature by using a simple and readily available starting material. This protocol can be scaled up to a wide range of glycosyl bromide donors and aryl olefin substrates. Mechanistic studies indicate that a radical addition pathway is involved.

Calcium-dependent proapoptotic effect of Taenia solium metacestodes annexin B1 on human eosinophils: a novel strategy to prevent host immune response.

Annexins are a family of calcium-dependent phospholipid-binding proteins that have been proposed to be involved in a wide range of important biological processes. At present, only a few annexins have been identified in parasites, and the physiological roles of these annexins are obscure. Earlier, we cloned a novel annexin (annexin B1) from Taenia solium metacestodes and found that annexin B1 was detectable in the surrounding host-derived layer with granulomaous infiltration. The objective of this study was to investigate the secretion and physiological function of annexin B1. We expressed a green fluorescent protein-tagged annexin B1 (GFP-anxB1) in living SiHa cells and showed that it was secreted upon stimulation with dexamethasone (Dex). This secretion was not inhibited by brefeldin A but was blocked by pre-treatment with the intracellular calcium-specific chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA/AM). Furthermore, we describe for the first time that annexin B1 can bind to the extracellular surface of human eosinophils and produce Ca(2+)-influx. The Ca(2+)-influx induced apoptosis in eosinophils, which was inhibited by pre-loading the Ca(2+) channel blocker 1-[beta-[3-(4-methoxyphenyl)propoxy]-4-metho-xyphenethyl]-1H-imidazole, HCl (SKF-96365). In conclusion, these findings represent direct and substantial evidence for the secretion of annexin B1 by living cells; the apoptosis in eosinophil induced by annexin B1 might be a novel strategy for T. solium metacestodes to prevent the host's immune attack.

Single-nucleotide polymorphisms of mismatch repair genes in healthy Chinese individuals and sporadic colorectal cancer patients.

Mismatch repair (MMR) genes are among of the most important genes associated with colorectal cancer (CRC). Single-nucleotide polymorphisms (SNPs) are generally thought to provide important information across a wide spectrum of life sciences; however, no study of association between SNPs of MMR genes and Chinese sporadic colorectal cancer (SCRC) is available. We chose 29 reported single-nucleotide variants that have rarely been verified in a population-based study. We identified SNPs and the genotype-phenotype association in Chinese populations of 150 healthy individuals and 160 SCRC patients. We extracted the genomic DNA from the blood of these individuals and used sequencing to determine these SNPs. Three SNPs (MLH1 394G-->C, 655A-->G, 1151T-->A) occurred with a frequency of 8.8-11.2% in the Chinese population. These SNPs formed a series with combined effects. The haplotype of concurrent MLH1 655 and 1151 SNPs and the haplotype combinations of MLH1 1151, MLH1 394 occurred exclusively in SCRC. None of the other 26 variants were detected in the Chinese population.