Continuous Intravenous versus Subcutaneous Administration of Insulin for Glycemic Variability in Acute Ischemic Stroke.

Background: Continuous intravenous infusion (IV) or subcutaneous injection (SC) of insulin was widely applied to control hyperglycemia after ischemic stroke. However, the impact of different administration modes on glycemic variability was unknown. Methods: Consecutive stroke patients treated with intravenous thrombolysis were screened. Subjects who received insulin treatment were included and entered into the IV or SC group according to the respective administration mode. Blood glucose was closely monitored within the first 72 hours, and the target range of glucose was from 7.7 to 10.0 mmol/L for all patients. The variabilities of glucose, assessed using standard deviation of the mean, variable coefficient and range from the maximum to the minimum value, were compared between the two groups. Results: A total of 130 patients were enrolled with 66 in the IV groups and 64 in the SC group. Compared with the SC group, the IV group had higher glycemic variability evaluated as either standard deviation (2.7 ± 0.7 mmol/L vs 2.2 ± 0.9 mmol/L, p = 0.002), variable coefficient (0.26 ± 0.06 vs 0.23 ± 0.08, p = 0.011) or range (10.0 ± 3.6 mmol/L vs 8.1 ± 3.1 mmol/L, p = 0.001). Multivariate logistic regression analyses found that continuous intravenous infusion was associated with higher level of the standard deviation (adjusted OR 3.01, 95% CI 1.29-7.28, p = 0.011), variable coefficient (adjusted OR 5.97, 95% CI 2.55-13.96, p < 0.001) and range (adjusted OR 6.08, 95% CI 2.63-14.05, p < 0.001). Conclusion: Continuous intravenous infusion of insulin was associated with higher glycemic variability than subcutaneous injection in acute stroke patients receiving thrombolysis.

Iron metabolism disorders in patients with hepatitis B-related liver diseases.

AIM: To investigate the relationship between levels of iron metabolism markers and hepatitis B virus (HBV)-related chronic liver diseases. METHODS: This case-control study with 318 participants included 78 cases of chronic hepatitis B, 85 cases of HBV-related liver cirrhosis, 77 cases of HBV-related hepatocellular carcinoma, and 78 healthy controls. Markers of iron metabolism were detected in participants. Hematological and biochemical parameters and HBV-DNA were assessed. Child-Pugh grade and Barcelona Clinic Liver Cancer stage were determined for each hepatocellular carcinoma patient. Perls' staining was performed on liver sections. The SPSS program was used for all statistical analyses, and statistical significance was considered if a P-value < 0.05. RESULTS: Significantly higher serum ferritin and lower serum hepcidin levels were detected in all groups of HBV-infected patients compared with healthy controls. Serum iron, total iron binding capacity, and serum transferrin levels were significantly lower in patients with cirrhosis and hepatocellular carcinoma, whereas the hepcidin level was higher than that in chronic hepatitis B patients. Correlation analysis indicated that serum hepcidin was negatively correlated with HBV-DNA load (P < 0.01). Serum ferritin and transferrin saturation levels increased proportionally to the extent of liver cirrhosis and poorer Child-Pugh scores (P < 0.05). The decreased serum iron and transferrin saturation levels were significantly correlated with a smaller hepatocellular carcinoma tumor burden according to Barcelona Clinic Liver Cancer staging. Liver histology showed a clearly increasing trend in iron deposition in the liver tissues with increased fibrosis, which became prominent at stages 3 (severe liver fibrosis) and 4 (cirrhosis). CONCLUSION: Iron metabolism disorders occur in patients with HBV-related liver diseases. The serum markers of iron metabolism disorders vary in different stages of HBV-related liver diseases.

miR-873 suppresses H9C2 cardiomyocyte proliferation by targeting GLI1.

MicroRNAs (miRNAs) are a class of endogenous, non-coding small RNAs that regulate the expression of target genes. Previous studies have suggested that miRNAs are key regulators in cardiovascular systems. This study investigated the role of miR-873 in H9C2 cardiomyocytes by targeting glioma-associated oncogene 1 (GLI1). miR-873 was significantly up-regulated in serum samples from congenital heart disease (CHD) patients compared with those from normal individuals. Furthermore, miR-873 over-expression suppressed H9C2 proliferation and induced cell cycle arrest. Bioinformatic algorithms revealed a predicted target site for miR-873 in the 3'-untranslated region (3'UTR) of GLI1, which was verified using a dual-luciferase reporter assay. qPCR and western blot analysis also showed that miR-873 negatively regulated GLI1 mRNA and protein expression in H9C2 cells. Conversely, GLI1 over-expression partially reversed the growth-inhibitory effect of miR-873. To summarize, our data suggest that miR-873 is a novel miRNA that regulates H9C2 cell proliferation via targeting GLI1, and miR-873 may serve as a new potential biomarker diagnosis in CHD in the future.

The Histone Methyltransferase DOT1L Promotes Neuroblastoma by Regulating Gene Transcription.

Myc oncoproteins exert tumorigenic effects by regulating expression of target oncogenes. Histone H3 lysine 79 (H3K79) methylation at Myc-responsive elements of target gene promoters is a strict prerequisite for Myc-induced transcriptional activation, and DOT1L is the only known histone methyltransferase that catalyzes H3K79 methylation. Here, we show that N-Myc upregulates DOT1L mRNA and protein expression by binding to the DOT1L gene promoter. shRNA-mediated depletion of DOT1L reduced mRNA and protein expression of N-Myc target genes ODC1 and E2F2 DOT1L bound to the Myc Box II domain of N-Myc protein, and knockdown of DOT1L reduced histone H3K79 methylation and N-Myc protein binding at the ODC1 and E2F2 gene promoters and reduced neuroblastoma cell proliferation. Treatment with the small-molecule DOT1L inhibitor SGC0946 reduced H3K79 methylation and proliferation of MYCN gene-amplified neuroblastoma cells. In mice xenografts of neuroblastoma cells stably expressing doxycycline-inducible DOT1L shRNA, ablating DOT1L expression with doxycycline significantly reduced ODC1 and E2F2 expression, reduced tumor progression, and improved overall survival. In addition, high levels of DOT1L gene expression in human neuroblastoma tissues correlated with high levels of MYCN, ODC1, and E2F2 gene expression and independently correlated with poor patient survival. Taken together, our results identify DOT1L as a novel cofactor in N-Myc-mediated transcriptional activation of target genes and neuroblastoma oncogenesis. Furthermore, they characterize DOT1L inhibitors as novel anticancer agents against MYCN-amplified neuroblastoma. Cancer Res; 77(9); 2522-33. ©2017 AACR.

A Myc Activity Signature Predicts Poor Clinical Outcomes in Myc-Associated Cancers.

Myc transcriptional activity is frequently deregulated in human cancers, but a Myc-driven gene signature with prognostic ability across multiple tumor types remains lacking. Here, we selected 18 Myc-regulated genes from published studies of Myc family targets in epithelial ovarian cancer (EOC) and neuroblastoma. A Myc family activity score derived from the 18 genes was correlated to MYC/MYCN/MYCL1 expression in a panel of 35 cancer cell lines. The prognostic ability of this signature was evaluated in neuroblastoma, medulloblastoma, diffuse large B-cell lymphoma (DLBCL), and EOC microarray gene expression datasets using Kaplan-Meier and multivariate Cox regression analyses and was further validated in 42 primary neuroblastomas using qPCR. Cell lines with high MYC, MYCN, and/or MYCL1 gene expression exhibited elevated expression of the signature genes. Survival analysis showed that the signature was associated with poor outcome independently of well-defined prognostic factors in neuroblastoma, breast cancer, DLBCL, and medulloblastoma. In EOC, the 18-gene Myc activity signature was capable of identifying a group of patients with poor prognosis in a "high-MYCN" molecular subtype but not in the overall cohort. The predictive ability of this signature was reproduced using qPCR analysis of an independent cohort of neuroblastomas, including a subset of tumors without MYCN amplification. These data reveal an 18-gene Myc activity signature that is highly predictive of poor prognosis in diverse Myc-associated malignancies and suggest its potential clinical application in the identification of Myc-driven tumors that might respond to Myc-targeted therapies. Cancer Res; 77(4); 971-81. ©2016 AACR.

VASP activation via the Gα13/RhoA/PKA pathway mediates cucurbitacin-B-induced actin aggregation and cofilin-actin rod formation.

Cucurbitacin B (CuB), a potent antineoplastic agent of cucurbitacin triterpenoids, induces rapid disruption of actin cytoskeleton and aberrant cell cycle inhibiting carcinogenesis. However, the underlying molecular mechanism of such anticancer effects remains incompletely understood. In this study, we showed that CuB treatment rapidly induced vasodilator-stimulated phosphoprotein (VASP) phosphorylation (i.e. activation) at the Ser157 residue and generated VASP clumps which were co-localized with amorphous actin aggregates prior to the formation of highly-ordered cofilin-actin rods in melanoma cells. Knockdown of VASP or inhibition of VASP activation using PKA-specific inhibitor H89 suppressed CuB-induced VASP activation, actin aggregation and cofilin-actin rod formation. The VASP activation was mediated by cAMP-independent PKA activation as CuB decreased the levels of cAMP while MDL12330A, an inhibitor of adenylyl cyclase, had weak effect on VASP activation. Knockdown of either Gα13 or RhoA not only suppressed VASP activation, but also ameliorated CuB-induced actin aggregation and abrogated cofilin-actin rod formation. Collectively, our studies highlighted that the CuB-induced actin aggregation and cofilin-actin rod formation was mediated via the Gα13/RhoA/PKA/VASP pathway.

Who is the king? The alpha-hydroxy-beta-oxo-alpha,beta-enone moiety or the catechol B ring: relationship between the structure of quercetin derivatives and their pro-oxidative abilities.

Quercetin and other flavonoids have been reported to exhibit both antioxidant and pro-oxidant properties. Most studies about the pro-oxidative ability were conducted in the presence of metal ions, and the essential functional moiety of quercetin responsible for the pro-oxidative effect is still unclear. In this study, we evaluated the pro-oxidative abilities in the absence of metal ions of two quercetin derivatives, i.e., quercetin-3'-O-beta-D-glucoside (1) and quercetin-3-O-beta-D-glucoside (2), by assessing DNA cleavage and HO(*)-radical production. The binding mode between these compounds and DNA was studied by fluorescence and viscometric titrations. The results showed that 1 can efficiently induce oxidative damage to plasmid DNA, while 2 shows poor activity. Both 1 and 2 bind to DNA via groove-binding. These results proved that the alpha-hydroxy-beta-oxo-alpha,beta-enone moiety contributes to the pro-oxidative activity of quercetin.

Activation of tissue transglutaminase transcription by histone deacetylase inhibition as a therapeutic approach for Myc oncogenesis.

Histone deacetylase (HDAC) inhibitors reactivate tumor suppressor gene transcription; induce cancer cell differentiation, growth arrest, and programmed cell death; and are among the most promising new classes of anticancer drugs. Myc oncoproteins can block cell differentiation and promote cell proliferation and malignant transformation, in some cases by modulating target gene transcription. Here, we show that tissue transglutaminase (TG2) was commonly reactivated by HDAC inhibitors in neuroblastoma and breast cancer cells but not normal cells and contributed to HDAC inhibitor-induced growth arrest. TG2 was the gene most significantly repressed by N-Myc in neuroblastoma cells in a cDNA microarray analysis and was commonly repressed by N-Myc in neuroblastoma cells and c-Myc in breast cancer cells. Repression of TG2 expression by N-Myc in neuroblastoma cells was necessary for the inhibitory effect of N-Myc on neuroblastoma cell differentiation. Dual step cross-linking chromatin immunoprecipitation and protein coimmunoprecipitation assays showed that N-Myc acted as a transrepressor by recruiting the HDAC1 protein to an Sp1-binding site in the TG2 core promoter in a manner distinct from it's action as a transactivator at E-Box binding sites. HDAC inhibitor treatment blocked the N-Myc-mediated HDAC1 recruitment and TG2 repression in vitro. In neuroblastoma-bearing N-Myc transgenic mice, HDAC inhibitor treatment induced TG2 expression and demonstrated marked antitumor activity in vivo. Taken together, our data indicate the critical roles of HDAC1 and TG2 in Myc-induced oncogenesis and have significant implications for the use of HDAC inhibitor therapy in Myc-driven oncogenesis.

The oxidative damage of plasmid DNA by ascorbic acid derivatives in vitro: the first research on the relationship between the structure of ascorbic acid and the oxidative damage of plasmid DNA.

To study the structure-function relationship of the oxidative-damage effect of ascorbic acid, we have focused on the interaction between plasmid DNA pUC19 and a series of ascorbic acid derivatives modified on different OH groups in the presence of transition metal ions. Some ascorbic acid derivatives can selectively cleave plasmid DNA from Form I to Form II in the presence of low concentration of Cu2+ just like ascorbic acid itself, while other derivatives oxidatively damage plasmid DNA slightly. We found that those derivatives with unattached 2-OH and 3-OH groups retain the ability to cleave the plasmid DNA. The derivatives that have been methylated on 2-OH or 3-OH can only cleave plasmid DNA softly, and those derivatives that have been protected on both 2-OH and 3-OH can hardly exert an oxidative damage on plasmid DNA under the same condition. Form these results, we can draw the conclusion that 2-OH and 3-OH groups of the ascorbic acid molecule contribute most to this biological activity.

Dinuclear macrocyclic polyamine zinc(II) complexes linked with flexible spacers: synthesis, characterization, and DNA cleavage.

Dinuclear macrocyclic polyamine zinc(II) complexes, which have two cyclen groups linked by flexible spacers, have been synthesized as DNA cleavage agents. The structures of these new dinuclear complexes are consistent with the data obtained from elemental analysis, MS and 1H NMR spectroscopy. The catalytic activity of these dinuclear complexes on DNA cleavage was studied. The results showed that the dinuclear zinc(II) complexes can catalyze the cleavage of supercoiled DNA (pUC 19 plasmid DNA) (Form I) under physiological conditions to produce selectively nicked DNA (Form II).

Dinuclear macrocyclic polyamine zinc(II) complexes: syntheses, characterization and their interaction with plasmid DNA.

The syntheses, characteristics of dinuclear macrocyclic polyamine zinc complexes and their interaction with plasmid DNA are reported. The two cyclen (1,4,7,10-tetraazacyclododecane) moieties are bridged by rigid and flexible linkages. The crystal structures of Zn2C27H43N8O15Cl4 [5c.(ClO4)3.2H2O] and Zn2C30H43N10O13Cl3 [5e.(ClO4)3.H2O] have been determined. The complexes crystallize in the monoclinic space group C2/c and P2(1)/c with the following unit cell parameters: 5c.(ClO4)3.2H2O: a=32.568(4)A, b=14.8593(17)A, c=19.443(2)A, alpha=90.00 degrees , beta=119.435(4) degrees , gamma=90.00 degrees , Dc=1.551 mg/m3, FW=956.71, F(000)=3932; 5e.(ClO4)3.H2O: a=15.807(2)A, b=16.756(2)A, c=16.161(2)A, alpha=90.00 degrees , beta=97.062(4) degrees , gamma=90.00 degrees , Dc=1.546 mg/m3, FW=988.83, F(000)=2032. The distance between the two Zn(II) ions is about 4.0 A. The structures show that two zinc ions can synergistically interact with the substrate DNA. With this novel structural characteristics, the dinuclear macrocyclic polyamine Zn(II) complexes via the synergetic effect between the two zinc ions can catalyze the cleavage of plasmid DNA (pUC18) with unprecedented speed at physiological conditions.