ACRIN 6684: Assessment of Tumor Hypoxia in Newly Diagnosed Glioblastoma Using 18F-FMISO PET and MRI.

PURPOSE: Structural and functional alterations in tumor vasculature are thought to contribute to tumor hypoxia which is a primary driver of malignancy through its negative impact on the efficacy of radiation, immune surveillance, apoptosis, genomic stability, and accelerated angiogenesis. We performed a prospective, multicenter study to test the hypothesis that abnormal tumor vasculature and hypoxia, as measured with MRI and PET, will negatively impact survival in patients with newly diagnosed glioblastoma. EXPERIMENTAL DESIGN: Prior to the start of chemoradiation, patients with glioblastoma underwent MRI scans that included dynamic contrast enhanced and dynamic susceptibility contrast perfusion sequences to quantitate tumor cerebral blood volume/flow (CBV/CBF) and vascular permeability (ktrans) as well as 18F-Fluoromisonidazole (18F-FMISO) PET to quantitate tumor hypoxia. ROC analysis and Cox regression models were used to determine the association of imaging variables with progression-free and overall survival. RESULTS: Fifty patients were enrolled of which 42 had evaluable imaging data. Higher pretreatment 18F-FMISO SUVpeak (P = 0.048), mean ktrans (P = 0.024), and median ktrans (P = 0.045) were significantly associated with shorter overall survival. Higher pretreatment median ktrans (P = 0.021), normalized RCBV (P = 0.0096), and nCBF (P = 0.038) were significantly associated with shorter progression-free survival. SUVpeak [AUC = 0.75; 95% confidence interval (CI), 0.59-0.91], nRCBV (AUC = 0.72; 95% CI, 0.56-0.89), and nCBF (AUC = 0.72; 95% CI, 0.56-0.89) were predictive of survival at 1 year. CONCLUSIONS: Increased tumor perfusion, vascular volume, vascular permeability, and hypoxia are negative prognostic markers in newly diagnosed patients with gioblastoma, and these important physiologic markers can be measured safely and reliably using MRI and 18F-FMISO PET. Clin Cancer Res; 22(20); 5079-86. ©2016 AACR.

Assessment of the repair and damage of DNA induced by parent and reduced RSU-1069, a 2-nitroimidazole-aziridine.

The cellular repair and damage of DNA induced by parent and reduced RSU-1069, a 2-nitroimidazole-aziridine, was assessed at both the molecular and cellular level. At the molecular level, after in vitro incubation with parent or reduced RSU-1069, plasmid DNA was transfected into Escherichia coli (AB1157) with subsequent selection for gene expression. For equivalent levels of DNA strand breakage following such treatment it is evident from the relative transformation frequencies that interactions with reduced RSU-1069 lead to DNA damage consistent with bifunctional action of a metabolite(s). At the cellular level, the cytoxicity of RSU-1069 was determined for a series of repair deficient mutants of E. coli under both aerobic and hypoxic conditions. The differential aerobic:hypoxic cytotoxicity ratio is approximately 3. We conclude that the repair of cellular DNA damage induced by RSU-1069 involves activation of the gene products under the control of the recA gene and not those under the control of the ada gene. The ability of cellular systems to repair damage induced by RSU-1069 may play a significant role in determining its efficiency to act as a hypoxic cell radiosensitizer and a hypoxia selective cytotoxin.

Quantitative cytochemical assessment of the neurotoxicity of misonidazole in the mouse.

A quantitative, cytochemical assay for measuring lysosomal enzymes in the peripheral nerves of mice has been developed. That the time course of lysosomal enzyme changes after misonidazole (MISO) treatment reflects the degree of neurotoxicity of this agent in the mouse, has been confirmed by the use of two known neurotoxic compounds: methyl mercury and acrylamide. This effect is specific to the peripheral nerves and was not found in liver, kidney, heart or cerebral cortex. Enzyme activities varied with mouse strain and sex, as did the response to MISO treatment. Of the mice studied, female C57 gave the greatest increase in beta-glucuronidase activity. With the MISO dose of 0.6 mg/g/dose the increased enzyme activity was independent of the route of administration and appeared to approach a plateau after 5 daily doses.