Background and Purpose-The goal of this study was to determine the efficacy of CT angiography for the characterization of plaque morphology and composition in carotid atherosclerotic disease. Methods-Fifty-five patients undergoing carotid endarterectomy were imaged preoperatively with single-slice spiral CT angiography. One hundred sixty-five endarterectomy sections were examined histologically at selected levels through the distal common and proximal internal carotid arteries. Plaque density was measured (in Hounsfield units) on axial CT sections, and the presence or absence of ulceration was noted. These observations were compared with the histological findings at corresponding levels. Data were analyzed with 2-sample t tests and 1-way analysis of variance (ANOVA). Results-ANOVA testing showed a statistically significant decrease in CT attenuation values with increasing plaque lipid but with a very high standard deviation of values. No other histological factor showed a statistically significant link with CT attenuation. Plaque ulceration was detected by CT with a sensitivity of 60% and a specificity of 74%. Conclusions-Analysis

Pediatric high-grade glioma (pHGG) and diffuse intrinsic pontine glioma (DIPG) are invasive tumors with poor survival. Oncolytic virotherapy, initially devised as a direct cytotoxic treatment, is now also known to act via immune-mediated mechanisms. Here we investigate a previously unreported mechanism of action: the inhibition of migration and invasion in pediatric brain tumors. We evaluated the effect of oncolytic herpes simplex virus 1716 (HSV1716) on the migration and invasion of pHGG and DIPG both in vitro using 2D (scratch assay, live cell imaging) and 3D (spheroid invasion in collagen) assays and in vivo using an orthotopic xenograft model of DIPG invasion. HSV1716 inhibited migration and invasion in pHGG and DIPG cell lines. pHGG cells demonstrated reduced velocity and changed morphology in the presence of virus. HSV1716 altered pHGG cytoskeletal dynamics by stabilizing microtubules, inhibiting glycogen synthase kinase-3, and preventing localized clustering of adenomatous polyposis coli (APC) to the leading edge of cells. HSV1716 treatment also reduced tumor infiltration in a mouse orthotopic xenograft DIPG model. Our results demonstrate that HSV1716 targets the migration and invasion of pHGG and DIPG and indicates the potential of an oncolytic virus (OV) to be used as a novel anti-invasive treatment strategy for pediatric brain tumors.

Paediatric high grade glioma (pHGG) and diffuse intrinsic pontine glioma (DIPG) are invasive tumours associated with poor survival. Oncolytic virotherapy, which uses viruses to selectively infect and destroy cancer cells and/ or stimulate an anti-tumour immune response, offers a novel treatment approach. Here, we evaluate the effects of oncolytic herpes simplex virus (HSV) 1716 on migration and invasion in in vitro and in vivo models of pHGG and DIPG. In vitro migratory characteristics were examined using 2D (scratch assay, live cell imaging) and 3D (spheroid invasion in collagen) assays. Oncolytic HSV resulted in blockade of both migration and invasion in all pHGG and DIPG cell lines and this did not appear to be a consequence of cytotoxicity or altered proliferation. pHGG cells demonstrated reduced velocity, loss of polarity and changed morphology in the presence of virus. Oncolytic HSV altered pHGG cytoskeletal dynamics, stabilising microtubules through accumulation of post-translational tubulin modifications. Furthermore, oncolytic HSV treatment of pHGG cell lines inhibited glycogen synthase kinase-3 (a key regulator of cell migration and microtubule dynamics) and prevented localised clustering of adenomatous polyposis coli to the leading edge of cells. Importantly, oncolytic HSV treatment reduced tumour infiltration and enhanced therapy in a mouse orthotopic xenograft model of DIPG. In conclusion, this study is the first to demonstrate that it is possible to target migration and invasion of pHGG and DIPG using oncolytic HSV. We propose that oncolytic HSV may have therapeutic benefits for pHGG and DIPG as an anti-invasive agent, improving outcomes for these devastating diseases.