Angiopoietin-2 decreases vascular endothelial growth factor expression by modulating HIF-1α levels in gliomas

Angiogenesis is thought to depend on a perfectly coordinated balance between endogenous-positive and negative regulatory factors. Of these factors, the vascular endothelial growth factor (VEGF) and angiopoietins (Angs) seem to play an essential role. Recently, we reported the expression of the Ang-natural receptor, Tie2, in neoplastic astrocytic cells within gliomas. Because of the VEGF/Ang2 functional partnership together with the presence of Tie2 in gliomas, we hypothesized a role of Ang2 on the modulation of VEGF levels in these tumors. We examined the effect of Ang2 on VEGF expression in a panel of glioma cells, which showed that Ang2 inhibited VEGF expression at both mRNA and protein levels in Tie2-expressing cells, but not in Tie2-negative cells. VEGF promoter analysis showed that Ang2 regulated VEGF expression at the transcriptional level in relation to a decrease in HIF-1alpha expression and HIF-DNA-binding activity. Tie2 silencing by siRNA rescued the Ang2-mediated downmodulation of VEGF, suggesting an essential role for Tie2 in this regulatory loop. To our knowledge, this is the first report on the role of Ang2/Tie2 in the regulation of HIF-1alpha/VEGF expression, providing additional evidence of the intrinsic coordination that occurs among these factors during angiogenesis.

Betaine supplementation improves the atherogenic risk factor profile in a transgenic mouse model of hyperhomocysteinemia

OBJECTIVE

To investigate the lipotropic action of betaine on plasma lipoproteins and tissue lipids.

METHODS AND RESULTS

Adult mice, wild type (+/+) or heterozygous (+/-) for a disruption of the methylenetetrahydrofolate reductase (Mthfr) gene, were supplemented with betaine for 1 year and compared with mice on control diets. Outcome measures were plasma homocysteine and lipoprotein levels, aortic and liver morphology, and liver staining for 3-nitrotyrosine (oxidative stress marker) and Apolipoprotein A-I (ApoA-I). We also investigated short-term effects of supplemental betaine on plasma lipoproteins in Mthfr +/+ and +/- mice. Both genotypes showed significantly lower plasma homocysteine after long-term betaine supplementation, and lower plasma triglycerides and higher HDL-cholesterol after both short- and long-term betaine. Lipid accumulation in liver and aortic wall tended to be lower in Mthfr+/+ compared to Mthfr+/- mice and in betaine-supplemented compared to unsupplemented mice. Nitrotyrosine staining was higher and ApoA-I staining was lower in livers of Mthfr+/- compared to Mthfr+/+ mice. Betaine did not affect staining of nitrotyrosine but increased ApoA-I staining. A significant negative correlation was observed between plasma homocysteine and liver ApoA-I.

CONCLUSIONS

Mild MTHFR deficiency in mice is associated with increased risk for atherosclerotic disease. Betaine has a lipotropic effect, which is associated with a reduction in homocysteine, an increase in ApoA-I and an amelioration of the atherogenic risk profile.

Plasticity of ovarian cancer cell SKOV3ip and vasculogenic mimicry in vivo

The aim of this study is to investigate the plasticity of human epithelial ovarian cancer cell SKOV3ip and formation of vasculogenic mimicry (VM) in vivo. SKOV3ip was transfected with lentiviral vector carrying green fluorescence protein (GFP). Female nude mice were implanted intraperitoneally with GFP-labled SKOV3ip. When the transplanted tumor reached a volume of approximately 1 cm(3), paraffin-embedded, formaldehyde-fixed tissue was prepared and stained with hematoxylin and eosin (H & E). Tumor tissues were also studied by electron microscopy and fluorescence microscopy. The results of H & E staining, electron microscopy, and fluorescence microscopy indicated SKOV3ip formed patterned networks with erythrocytes in them, in the absence of vascular epithelial cells, which was a sign that SKOV3ip engaged in VM in vivo. Expression of vascular epithelium marker CD31 was investigated by immunohistochemical staining, immunofluorescence assay, semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), and flow cytometric analysis (FACS). Factor VIII and vascular endothelial growth factor (VEGF) were also analyzed by FACS. Weak and focal CD31 immunohistochemical staining was found along the channels of tumor cells. Immunofluorescence assay and RT-PCR demonstrated that CD31 was expressed in primary-cultured SKOV3ip. CD31 and Factor VIII, but not VEGF were detected in primary-cultured SKOV3ip by FACS. The present study has shown that human ovarian cancer cell line SKOV3ip may be able to express some specific markers of vascular epithelial cells and has plasticity to form VM in vivo. In the following study, we indicated that hypoxia-inducible factor (HIF)-1alpha inhibitor, rapamycin, could possibly prevent VM and phenotype transformation of SKOV3ip, reflected by down-regulating expression of CD31 and Factor VIII. HIF-1alpha protein expression correlated with CD31 and Factor VIII protein expression in SKOV3ip. These results indicated that VM might be associated with HIF-1alpha.

The Phosphoinositide-Dependent Kinase-1 Inhibitor 2-Amino-N-[4-[5-(2-phenanthrenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]phenyl]-acetamide (OSU-03012) Prevents Y-Box Binding Protein-1 from Inducing Epidermal Growth Factor Receptor

The epidermal growth factor receptor (EGFR) is integral to basal-like and human epidermal growth factor receptor-2 (Her-2)-overexpressing breast cancers. Such tumors are associated with poor prognosis, the majority of which express high levels of EGFR. We reported that EGFR expression is induced by the oncogenic transcription factor Y-box binding protein-1 (YB-1) that occurs in a manner dependent on phosphorylation by Akt. Herein, we questioned whether blocking Akt with 2-amino-N-[4-[5-(2-phenanthrenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]phenyl]-acetamide (OSU-03012), a phosphoinositide-dependent protein kinase-1 (PDK-1) small-molecule inhibitor, could prevent YB-1 from binding to the EGFR promoter. MDA-MB-468 and SUM 149 are basal-like breast cancer (BLBC) cells that were used for our studies because they express high levels of activated PDK-1, YB-1, and EGFR compared with the immortalized breast epithelial cell line 184htrt. In these cell lines, YB-1 preferentially bound to the -1 kilobase of the EGFR promoter, whereas this did not occur in the 184htrt cells based on chromatin immunoprecipitation. When the cells were exposed to OSU-03012 for 6 h, YB-1/EGFR promoter binding was significantly attenuated. To further confirm this observation, gel-shift assays showed that the drug inhibits YB-1/EGFR promoter binding. The inhibitory effect of OSU-03012 on EGFR was also observed at the mRNA and protein levels. OSU-03012 ultimately inhibited the growth of BLBC in monolayer and soft agar coordinate with the induction of apoptosis using an Array-Scan VTI high-content screening system. Furthermore, OSU-03012 inhibited the expression of EGFR by 48% in tumor xenografts derived from MDA-MB-435/Her-2 cells. This correlated with loss of YB-1 binding to the EGFR promoter. Hence, we find that OSU-03012 inhibits YB-1 resulting in a loss of EGFR expression in vitro and in vivo.

Results of a randomized phase III study to compare the overall survival of gefitinib (IRESSA) versus docetaxel in Japanese patients with non-small cell lung cancer who failed one or two chemotherapy regimens

LBA7509

Background: This phase III study (V-15–32) compared gefitinib vs docetaxel on overall survival (OS) in Japanese patients (pts) with pretreated advanced NSCLC. Methods: Pts with advanced or metastatic (Stage IIIb or IV) NSCLC who failed 1 or 2 chemotherapy regimens were randomized to gefitinib (250 mg/day) or docetaxel (60 mg/m2 every 3 weeks). Non-inferiority of the primary endpoint, OS, was assessed by the confidence interval (CI) of the hazard ratio (HR; gefitinib/docetaxel) derived from an unadjusted Cox proportional hazard model. Results: 489 eligible pts were recruited. Non-inferiority in OS was not achieved (HR 1.12; 95.24% CI 0.89, 1.40) according to predefined criterion (upper CI limit for HR <1.25); however, no significant difference in OS (p=0.330) or PFS (p=0.335) was apparent between treatments. Post study, 36% of gefitinib-treated pts received subsequent docetaxel and 40% received no other therapy apart from gefitinib; 53% of docetaxel-treated pts received subsequent gefitinib and 26% received no other therapy apart from docetaxel. Gefitinib significantly improved ORR (22.5% vs 12.8%; p=0.009), TTF (HR 0.63; 95% CI 0.51, 0.77; p<0.001), and QoL (FACT-L trial outcome index 20.5% vs 8.7%; p=0.002; FACT-L 23.4% vs 13.9%; p=0.023), vs docetaxel. Additional subgroup analyses will be presented. Grade 3/4 AEs occurred in 40.6% (gefitinib) and 81.6% (docetaxel) of pts. Incidence of interstitial lung disease (ILD) was 5.7% (n=14) and 2.9% (n=7), respectively. There were 4 deaths due to AEs in the gefitinib arm (3 possibly treatment-related due to ILD; 1 due to pneumonia that was not considered treatment-related) and none in the docetaxel arm. Conclusions: Whilst non-inferiority in OS between gefitinib and docetaxel was not demonstrated according to predefined criteria, there was no statistically significant difference in survival between the two arms. Secondary endpoints largely unaffected by subsequent therapy provide further evidence of clinical efficacy of gefitinib in these pts. AEs were consistent with those previously observed for both treatments.

[Table: see text]

Stimulation of rat erythrocyte P2X7 receptor induces the release of epoxyeicosatrienoic acids

BACKGROUND AND PURPOSE

Red blood cells (RBCs) are reservoirs of vasodilatory, antiaggregatory, and antiinflammatory lipid mediators-epoxyeicosatrienoic acids (EETs). This study addresses the formation and release of erythrocyte-derived EETs in response to ATP receptor stimulation that may represent an important mechanism regarding circulatory regulation.

EXPERIMENTAL APPROACH

Erythrocyte EET formation and release were investigated by incubating rat RBCs in physiological salt solution with agents that effected ATP release via P2 receptor stimulation of phospholipase A2 and epoxygenase-like activities with activation of the ATP secretory mechanism. EETs were analyzed by gas and liquid chromatography-mass spectrometry.

KEY RESULTS

EETs were released from rat RBCs: 14,15-, 11,12-, 8,9- and 5,6-EETs in a ratio of 1.2:1.0:0.9:0.8. EETs were produced by epoxidation of arachidonic acid catalyzed by hemoglobin. Spontaneous release of EETs, 0.66+/-0.14 ng per 10(9) RBCs, was dose-dependently increased by an ATP analog, BzATP, and inhibited by P2X(7) receptor antagonists. 5 microM ATP increased release of EETs over 20% to 0.83+/-0.15 ng per 10(9) RBCs; 10 microM BzATP tripled the amount of EET release to 1.87+/-0.20 ng per 10(9) RBCs. EET release by ATP or BzATP was not associated with hemolysis. Carbenoxolone, a gap junction inhibitor that inhibits ATP release, and glibenclamide, an inhibitor of the cystic fibrosis transmembrane conductance regulator (CFTR), which is required for ATP release, inhibited the spontaneous and stimulated EET release from RBCs.

CONCLUSIONS AND IMPLICATIONS

EETs are produced and released from RBCs via a mechanism that is mediated by ATP stimulation of P2X(7) receptors coupled to ATP transporters, pannexin-1 and CFTR.

Combination of the oncolytic adenovirus ICOVIR-5 with chemotherapy provides enhanced anti-glioma effect in vivo

Novel therapies are clearly needed for gliomas, and the combination of oncolytic vectors with chemotherapy possesses a significant hope for the treatment of this malignancy. In addition, combination with chemotherapy allows for lower virus doses to achieve anticancer effect, thus resulting in lower undesirable toxicities due to viral proteins. In this work, we sought to determine whether combination of an oncolytic adenovirus ICOVIR-5, with RAD001 or temozolomide (TMZ) could result in enhanced anti-glioma effect in vivo. We assessed the in vitro cytotoxic effect and replication properties of ICOVIR-5 in combination with RAD001 or TMZ in U87 MG glioma cell line by MTT and TCID(50), respectively. Our data showed that in vitro treatment with RAD001 or TMZ not only interfered with adenovirus replication but, in addition, enhanced its oncolytic properties. To evaluate the in vivo anticancer effect, athymic mice bearing glioma xenografts (5 x 10(5) U87 MG cells/animal) received a single intratumoral injection of ICOVIR-5 (10(7) PFU/animal). RAD001 was given as a regimen of 5 mg/kg 5 days per week until the end of the experiment and TMZ was administered for 5 days at 7.5 mg/kg/mice. Of significance, combination of ICOVIR-5 with RAD001 or TMZ showed a potent anti-glioma effect in vivo, resulting in a dramatic extension of the median animal survival and in 20-40% animals becoming free of disease beyond 90 days.

Antisense integrin alphaV and beta3 gene therapy suppresses subcutaneously implanted hepatocellular carcinomas

BACKGROUND

Integrin alphaVbeta3 plays a critical role in tumour angiogenesis and metastasis formation, and is recognized as a key therapeutic target in the treatment of cancer.

AIM

To investigate whether antisense alphaV and beta3 gene therapy has utility in the treatment of hepatocellular carcinomas.

METHODS

Antisense expression plasmids targeting integrin alphaV or beta3 were constructed, and examined by immunohistochemistry and Western blot analyses for their ability to inhibit alphaV and beta3 expression. The antisense alphaV and beta3 expression vectors, either alone or in combination, were injected into HepG2 hepatomas established subcutaneously in nude mice and tumour growth, angiogenesis and apoptosis were monitored.

RESULTS

Antisense alphaV and beta3 downregulated the alphaV and beta3 subunits expressed by human umbilical vein endothelial cells, and the alphaV subunit expressed by HepG2 cells. Gene transfer of antisense alphaV and beta3 expression vectors downregulated alphaV and beta3 in HepG2 tumours established in nude mice, inhibited tumour vascularization and growth, and enhanced tumour cell apoptosis. Antisense alphaV suppressed tumour growth more strongly than antisense beta3; however antisense therapy that simultaneously targeted both integrin subunits was more effective than the respective monotherapies. Antisense alphaV and beta3 inhibited tumour angiogenesis to similar extents, by a process that is independent of vascular endothelial growth factor.

CONCLUSIONS

Antisense gene therapy targeting alphaV integrins warrants consideration as an approach to treat hepatocellular carcinomas.

Molecular Dynamics Simulations of Methane Hydrate Using Polarizable Force Fields

Molecular dynamics simulations of methane hydrate have been carried out using the polarizable AMOEBA and COS/G2 force fields. Properties calculated include the temperature dependence of the lattice constant, the OC and OO radial distribution functions, and the vibrational spectra. Both the AMOEBA and COS/G2 force fields are found to successfully account for the available experimental data, with overall somewhat better agreement with experiment being found for the AMOEBA model. Comparison is made with previous results obtained using TIP4P and SPC/E effective two-body force fields and the polarizable TIP4P-FQ force field, which allows for in-plane polarization only. Significant differences are found between the properties calculated using the TIP4P-FQ model and those obtained using the other models, indicating an inadequacy of restricting explicit polarization to in-plane only.

Malignant triton tumour of the parapharyngeal space: a case arising from the cervical sympathetic nerve

BACKGROUND

Malignant triton tumour is a relatively rare, aggressive sarcoma comprising both malignant schwannoma cells and malignant rhabdomyoblasts. Malignant triton tumour of the parapharyngeal space is exceptionally rare, with only one case being described in the literature. Malignant triton tumour of the cervical sympathetic nerve has not previously been reported.

METHODS

We report a case involving the parapharyngeal space and arising from the cervical sympathetic nerve, and we review the management and outcome of the previous case reported in this rare location.

CONCLUSIONS

The parapharyngeal space is a unique location. Owing to this specific localisation, adjuvant therapy in addition to complete resection may be important in the treatment of malignant triton tumour in this rare location.

A new automatic skeletonization algorithm for 3D vascular volumes

Extraction of the skeleton of vascular structures is an important procedure for computer aided analysis of vascular data. A new automatic skeletonization algorithm for 3D vascular volumes is proposed. Two types of distance maps and clusters, a set of connected points with the same property are used to represent the vascular structure. Using clusters representation, branch information can be retrieved efficiently. In each identified branch, preliminary points, defined as skeleton nodes, are derived hierarchically which are later interpolated to generate the skeleton. The algorithm was tested on MR angiography arterial and venous 3D vascular volumes. The extracted skeletons were reliable representation of the vascular structure. Compared to other 3D distance-based skeletonization algorithms, the new approach yields a more centered skeleton without complex post-processing. The skeleton is also insensitive to boundary complexity and can be easily modified by the user.

Association analysis of vitamin D-binding protein gene polymorphisms with variations of obesity-related traits in Caucasian nuclear families

BACKGROUND

Vitamin D-binding protein (DBP) gene is well known for its function on glucose and vitamin D metabolism in human populations. Previous studies suggested that the in vivo DBP level may play a role in the etiology of obesity. However, few studies explored the contribution of DBP gene to the variance of obesity phenotypes.

OBJECTIVE

To investigate the relationship of DBP polymorphisms and obesity in Caucasian nuclear families.

DESIGN

We genotyped 14 single-nucleotide polymorphisms (SNPs) located in and around the DBP gene in 1873 Caucasian subjects from 405 nuclear families. Three obesity-related quantitative phenotypes were investigated, including body mass index (BMI), fat mass and percentage of fat mass (PFM). Single SNPs and haplotypes (three blocks) were tested by family-based association using the FBAT software.

RESULTS

SNP2 (rs17467825) and its corresponding haplotype GAA (frequency 0.270) in block 1 showed strongest associations with PFM (P=0.0011 and 0.0023, respectively). In multivariate test significant association was also observed for SNP2 with fat mass&BMI&PFM (P=0.0098). Subsequent sex-stratified analyses demonstrated nominal association for SNP2 and haplotype GAA with PFM in the female subgroup.

CONCLUSION

Polymorphisms of DBP gene were significantly association with human PFM, especially in female, suggesting the importance of DBP gene in the pathogenesis of human obesity.

Confirmation of four nitroimidazoles in porcine liver by liquid chromatography–tandem mass spectrometry

A sensitive and reliable multiresidue method is described for analysis of ronidazole, metronidazole, dimetridazole and the common metabolite of ronidazole and dimetridazole, 2-hydroxymethyl-1-methyl-5-nitroimidazole in swine liver. The sample preparation procedure was based on liquid-liquid extraction and mixed mode cation exchange/reverse phase solid-phase extraction. The compounds of interest were determined by reverse phase gradient liquid chromatography separation and tandem mass spectrometry (MS/MS) in the multiple reaction monitoring (MRM) mode. The limits of confirmation were 0.1-0.5 microg kg(-1) for the analytes.

Scaling properties of hyperon production in Au+Au collisions at square root [sNN]=200 GeV

We present the scaling properties of Lambda, Xi, and Omega in midrapidity Au+Au collisions at the Brookhaven National Laboratory Relativistic Heavy Ion Collider at sqrt[s_{NN}]=200 GeV. The yield of multistrange baryons per participant nucleon increases from peripheral to central collisions more rapidly than that of Lambda, indicating an increase of the strange-quark density of the matter produced. The strange phase-space occupancy factor gamma_{s} approaches unity for the most central collisions. Moreover, the nuclear modification factors of p, Lambda, and Xi are consistent with each other for 2<p_{T}<5 GeV/c in agreement with a scenario of hadron formation from constituent quark degrees of freedom.

Transplantation of embryonic stem cell-derived cardiomyocytes improves cardiac function in infarcted rat hearts

BACKGROUND

Post-infarct congestive heart failure is one of the leading causes of morbidity and mortality in industrialized countries. The main purpose of this study was to investigate whether transplantation of embryonic stem cell-derived cardiomyocytes (ESCM) directly into the infarcted myocardium could improve cardiac function in rats.

METHODS

Cell culture medium with or without ESCM was injected into the borders of cardiac scar tissue 1 week after experimental infarction. Cardiac performance was evaluated 4 weeks later by means of echocardiography after ESCM (n=16) or medium (n=12) injection.

RESULTS

ESCM implantation significantly improved fractional shortening (31.5+/-3. 8%) compared with medium-treated hearts (21.3+/-5.2%; P<0.05) and preserved left ventricular structure. Co-localization of 4',6-diamidino-2-phenylindole-labeled nuclei of transplanted cells with cardiomyocyte markers for cardiac troponin T and connexin-43, as detected by immunofluorescent microscopy, indicated the regeneration of damaged myocardium and the formation of gap junctions between grafted and host cells. However, intra-myocardial teratomas were observed in the hearts of two of the 16 grafted animals, at the fourth week after ESCM transplantation.

DISCUSSION

Our results suggest that, although ESCM implantation can improve the function of infarcted myocardium, strategies to prevent tumorigenesis should be developed.

Longitudinal double-spin asymmetry and cross section for inclusive jet production in polarized proton collisions at square root of s = 200 GeV

We report a measurement of the longitudinal double-spin asymmetry A(LL) and the differential cross section for inclusive midrapidity jet production in polarized proton collisions at square root of s = 200 GeV. The cross section data cover transverse momenta 5 < pT < 50 GeV/c and agree with next-to-leading order perturbative QCD evaluations. The A(LL) data cover 5 < pT < 17 GeV/c and disfavor at 98% C.L. maximal positive gluon polarization in the polarized nucleon.

Airway hyperresponsiveness induced by repetitive intraperitoneal injection of lipopolysacharide and the involvement of inflammation and nitric oxide in guinea pigs

OBJECTIVE

Airway hyperresponsiveness (AHR) is involved in bronchial asthma and chronic obstructive pulmonary disease (COPD) and produces respiratory symptoms. Lipopolysaccharide (LPS) has been found to be significantly related to the severity of asthma. However, its clinical mechanism still remains controversial. This study investigated the in vivo effect of repetitive intraperitoneal administration of lipopolysaccharide (LPS) on airway hyperresponsiveness (AHR) in guinea pigs and the possible involvement of inflammation, nitric oxide (NO) and nitric oxide synthase (NOS).

METHODS

There were two exposure groups for intraperitoneal LPS injection: (1) LPS was given at a dose of 1 mg x kg(-1), followed by sterile saline (NS) 1 ml x kg(-1) 8 h later every 24 h; (2) LPS was given at a dose of 0.5 mg x kg(-1) two times with an interval of 8 h every 24 h. Each exposure regime was repeated 4 times. Control animals were given NS and 6 naive guinea pigs were used as baseline control. Determinations were made 24 h after each exposure.

RESULTS

Persistent AHR occurred 24 h after the third and fourth exposures to LPS in the first exposure group (at one dose), but occurred earlier after the exposures to LPS in the second exposure group (at divided doses). The numbers of total cells and neutrophils were elevated initially but subsided subsequently in LPS-treated groups. No evidence of morphological changes in the small airways was found 24 h after any of the exposures. The Ca(2+)-dependent and Ca(2+)-independent NOS activities (mainly produced by iNOS) in the BALF, as well as the production of NO, were significantly elevated 24 h after any of third and fourth exposures in LPS-treated groups.

CONCLUSIONS

Our results demonstrate that repetitive intraperitoneal LPS can induce persistent AHR which occurs earlier when the frequency of injection increase, and an elevation of NO production and iNOS activity may be involved in is systemic-LPS-induced AHR.

The study of peripheral blood mononuclear cell MHC I and MHC II gene mRNA expression in acute graft rejection

BACKGROUND

Early diagnosis of acute graft rejection is important in the clinic. To explore a reliable diagnostic marker, we selected skin-grafted rabbits as an animal model to study peripheral blood mononuclear cell (PBMC) major histocompatibility complex 1 (MHC I) and MHC II gene mRNA in acute graft rejection (AGR).

METHODS

Fifteen New Zealand white rabbits were randomly divided into three groups to observe skin graft rejection: three rabbits were in the autograft control group; six rabbits in a cyclosporine (CsA) treated allografted group; and the other six rabbits in untreated allografted group. The CsA-treated allografted group was given CsA (5 mg/kg) daily intramuscularly. PBMC samples were obtained every 2 days to detect by real-time polymerase chain reaction, PBMC MHC I and MHC II gene mRNA.

RESULTS

MHC I and MHC II gene mRNA levels did not show any obvious change in the autografted controls. MHC I gene mRNA levels showed a slow increase in the CsA-treated allografted group, but no obvious change in the untreated allografted group. MHC II gene mRNA reached the highest level at 2 to 3 days before graft rejection appeared macroscopically in the CsA-treated allografted group and untreated allografted group, then decreasing to a low level.

CONCLUSION

Compared with MHC I gene mRNA expression, PBMC MHC II gene mRNA expression may be considered to be an earlier marker for AGR.