Citations

Abstract Rationale: Given recent success in delivering interferon-beta (IFNβ) using replication incompetent adenovirus in patients with malignant pleural effusions, we hypothesized that vectors that could replicate (inducing oncolysis) and express IFNβ at high level would be more effective. Both vaccinia virus (VV) and vesicular stomatitis (VSV) expressing mouse IFNβ have been constructed in a manner to improve their safety and efficacy as oncolytic vectors. In this study, we evaluated these two oncolytic vectors in different murine thoracic cancer models for clinical translation. Experimental procedures: We compared the efficacy of VVIFNβ and VSVIFNβ to kill 3 mouse lung cancer and 4 mouse mesothelioma lines in vitro over a 5 day-period assessing cell viability by MTT assay. The amount of IFNβ produced by these two vectors were measured with ELISA. The viral replication in infected mice was assessed by measuring viral titers in both immunocompetent and immunodeficient mice bearing an IFN-non-responsive AB12 tumor, following intratumoral injection of either vector at 108 pfu/mouse. To assess their anti-tumor activity, the two vectors were also given at 108 pfu/mouse intratumorally in mice bearing two lung cancer tumors on their flanks. Results: The replication of VSVIFNβ and its killing ability was limited in some of the tumor lines. This appeared to be due to an intact IFN response pathway. In contrast, VVIFNβ was able to kill all of the tumor lines. In culture, VSV replicates faster than VV, which resulted in faster cell killing (in susceptible cell lines), but with less IFNβ production. The amount of IFNβ production by VVIFNβ was comparable with AdIFNβ over a 5 day period. VVIFNβ-infected immunodeficient mice showed minimal or no toxicity when given virus intravenously, while all 5 mice infected with VSVIFNβ developed neurotoxicity within a week. In the TC-1 lung cancer model, VVIFNβ caused tumor regression, while VSVIFNβ and AdIFNβ were completely ineffective. In a second model using LKRM2, all 3 viral vectors were equivalent. The anti-tumor effect of VVIFNβ was shown to be mainly CD8 dependant, as depletion of CD8 with antibody dampened the tumor growth inhibition from 48% to 20%. Conclusions: Overall, VVIFNβ appears to be a better oncolytic vector than VSVIFNβ for a number of reasons: 1) it is safer, 2) it is able to replicate in vitro and in vivo in almost every cell line tested, 3) it induces longer and larger IFNβ production, and 4) it can potentially be given intravenously. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1513.

Abstract Epidermal growth factor receptor (EGFR) vIII is a mutated EGFR that is frequently overexpressed in glioblastomas and implicated in response to receptor tyrosine kinase inhibitors. In this study, we investigate the effect of ZD6474 (ZACTIMA, vandetanib), a dual inhibitor for vascular endothelial growth factor receptor 2 and EGFR on growth and angiogenesis of gliomas expressing EGFRvIII. We used two glioma xenograft models, U87MG cells overexpressing EGFRvIII and short-term cultured primary glioma GBM8 cells with EGFRvIII. ZD6474 inhibited tumor growth and angiogenesis and induced cell apoptosis in various brain gliomas. Moreover, significant inhibition of EGFRvIII-expressing U87MG and GBM8 gliomas was observed compared with their controls. Magnetic resonance imaging analysis using the apparent diffusion coefficient and three-dimensional T2*weighed measurements validated ZD6474 inhibition on tumor growth and angiogenesis in EGFRvIII-expressing GBM8 gliomas. Mechanistically, ZD6474 shows better inhibition of cell growth and survival of U87MG/EGFRvIII, GBM6, and GBM8 cells that express EGFRvIII than U87MG or GBM14 cells that have nondetectable EGFRvIII through attenuation of activated phosphorylation of signal transducer and activator of transcription 3, Akt, and Bcl-XL expression. Albeit in lesser extent, ZD6474 also displays suppressions of U87MG/EGFR and GBM12 cells that overexpress wild-type EGFR. Additionally, ZD6474 inhibits activation of extracellular signal-regulated kinase 1/2 in both types of cells, and expression of a constitutively active phosphoinositide 3-kinases partially rescued ZD6474 inhibition in U87MG/EGFRvIII cells. Taken together, these data show that ZD6474 significantly inhibited growth and angiogenesis of gliomas expressing EGFRvIII by specifically blocking EGFRvIII-activated signaling mediators, suggesting a potential application of ZD6474 in treatments for glioblastomas that overexpress EGFRvIII. Mol Cancer Ther; 9(4); 929–41. ©2010 AACR.

To investigate the role of HLA-DQ2 in the pathogenesis of associated immune disorders, we generated transgenic mice that expressed HLA-DQ2 in the absence of endogenous murine class II molecules (AE 0 DQ2). These AE 0 DQ2 mice with a mixed genetic background spontaneously developed skin lesions on their ears, whereas control AE 0 DQ6 genotype control mice (also with a mixed genetic background) did not. The skin lesions were characterized by deep subepidermal blistering with hydropic degeneration and lymphoid infiltration in the subepidermal area as determined by histopathology. Immunofluorescence analysis revealed thick band-like granular deposition of IgG, IgM, and a thin band of IgA deposition along the basement membrane. AE 0 DQ2 mice also developed significant and progressive hematuria and proteinuria as compared with the AE 0 DQ6 mice (p < 0.05). Histopathology showed immune complex deposits in the glomeruli of AE 0 DQ2 mice. Immunofluorescence analysis showed progressive mesangial and capillary wall deposition of IgA, IgM, IgG and C1q in the kidney. With electron microscopy, the deposits showed a ‘fingerprint’ substructure; and tubuloreticular structures were identified within endothelial cells. Conversely, these changes were not observed in AE 0 DQ6 mice. Serum anti-double stranded (ds)DNA IgM and IgG levels were also significantly elevated among AE 0 DQ2 mice compared with AE 0 DQ6 mice (p < 0.001). In conclusion, AE 0 DQ2 mice spontaneously develop an autoimmune lupus-like syndrome and are useful model for this disease. It remains to be determined whether genetic admixture played a role in the development of this systemic lupus erythematosus-like syndrome in HLA-DQ2 transgenic mice. Lupus (2010) 19, 815—829.

Insulin stimulates glucose transport in fat and skeletal muscle cells primarily by inducing the translocation of GLUT4 (glucose transporter isoform 4) to the PM (plasma membrane) from specialized GSVs (GLUT4 storage vesicles). Glycosphingolipids are components of membrane microdomains and are involved in insulin-regulated glucose transport. Cellular glycosphingolipids decrease during adipocyte differentiation and have been suggested to be involved in adipocyte function. In the present study, we investigated the role of glycosphingolipids in regulating GLUT4 translocation. We decreased glycosphingolipids in 3T3-L1 adipocytes using glycosphingolipid synthesis inhibitors and investigated the effects on GLUT4 translocation using immunocytochemistry, preparation of PM sheets, isolation of GSVs and FRAP (fluorescence recovery after photobleaching) of GLUT4–GFP (green fluorescent protein) in intracellular structures. Glycosphingolipids were located in endosomal vesicles in pre-adipocytes and redistributed to the PM with decreased expression at day 2 after initiation of differentiation. In fully differentiated adipocytes, depletion of glycosphingolipids dramatically accelerated insulin-stimulated GLUT4 translocation. Although insulin-induced phosphorylation of IRS (insulin receptor substrate) and Akt remained intact in glycosphingolipid-depleted cells, both in vitro budding of GLUT4 vesicles and FRAP of GLUT4–GFP on GSVs were stimulated. Glycosphingolipid depletion also enhanced the insulin-induced translocation of VAMP2 (vesicle-associated membrane protein 2), but not the transferrin receptor or cellubrevin, indicating that the effect of glycosphingolipids was specific to VAMP2-positive GSVs. Our results strongly suggest that decreasing glycosphingolipid levels promotes the formation of GSVs and, thus, GLUT4 translocation. These studies provide a mechanistic basis for recent studies showing that inhibition of glycosphingolipid synthesis improves glycaemic control and enhances insulin sensitivity in animal models of Type 2 diabetes.

Background— Sudden infant death syndrome (SIDS) is a leading cause of death during the first 6 months after birth. About 5% to 10% of SIDS may stem from cardiac channelopathies such as long-QT syndrome. We recently implicated mutations in α1-syntrophin (SNTA1) as a novel cause of long-QT syndrome, whereby mutant SNTA1 released inhibition of associated neuronal nitric oxide synthase by the plasma membrane Ca-ATPase PMCA4b, causing increased peak and late sodium current ( I Na ) via S-nitrosylation of the cardiac sodium channel. This study determined the prevalence and functional properties of SIDS-associated SNTA1 mutations. Methods and Results— Using polymerase chain reaction, denaturing high-performance liquid chromatography, and DNA sequencing of SNTA1 ’s open reading frame, 6 rare (absent in 800 reference alleles) missense mutations (G54R, P56S, T262P, S287R, T372M, and G460S) were identified in 8 (≈3%) of 292 SIDS cases. These mutations were engineered using polymerase chain reaction–based overlap extension and were coexpressed heterologously with SCN5A, neuronal nitric oxide synthase, and PMCA4b in HEK293 cells. I Na was recorded using the whole-cell method. A significant 1.4- to 1.5-fold increase in peak I Na and 2.3- to 2.7-fold increase in late I Na compared with controls was evident for S287R-, T372M-, and G460S-SNTA1 and was reversed by a neuronal nitric oxide synthase inhibitor. These 3 mutations also caused a significant depolarizing shift in channel inactivation, thereby increasing the overlap of the activation and inactivation curves to increase window current. Conclusions— Abnormal biophysical phenotypes implicate mutations in SNTA1 as a novel pathogenic mechanism for the subset of channelopathic SIDS. Functional studies are essential to distinguish pathogenic perturbations in channel interacting proteins such as α1-syntrophin from similarly rare but innocuous ones.