Combined Magnetic Resonance And Fluorescence-Protein Imaging To Simultaneously Assess The Anti-Tumor And Anti-Angiogenesis Efficacy Of Selenium

In this report, we determined the feasibility to combine fluorescent protein imaging (FPI) and magnetic resonance imaging (MRI) to demonstrate the efficacy of selenium on tumor progression and angiogenesis of colon cancer in an orthotopic model. GEO human colon carcinoma cells expressing green fluorescent protein (GFP), were implanted orthotopically into the colon of athymic nude mice. Beginning 5 days post implantation, whole body FPI was performed to monitor tumor growth in vivo. Upon visualization of tumor growth by FPI, animals were randomly assigned to either a control group or a treatment group. Treatment consisted of daily oral administration of the organoselenium compound, methyselenocysteine (MSC; 0.2 mg/day × 5 weeks). Longitudinal monitoring of tumor growth was performed using FPI and MRI. In addition, dynamic contrast-enhanced MRI was performed to examine the change in tumor blood volume following treatment. Changes in tumor vascularity visualized by imaging were correlated with immunohistochemical determination of microvessel density. Both FPI and MRI allowed non-invasive visualization of the longitudinal growth of orthotopic colon tumors. While T1- and T2-weighted MRI provided adequate contrast and volumetric assessment of GEO tumor growth, GFP imaging allowed for high-throughput visualization of tumor progression. Selenium treatment resulted in a significant reduction in blood volume and microvessel density of GEO tumors. A significant inhibition of tumor growth was also observed in selenium-treated animals compared to untreated control animals. Together, these results highlight the usefulness of multimodal imaging approaches to demonstrate antitumor and anti-angiogenesis efficacy and the potential of selenium treatment of colon cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4284. doi:10.1158/1538-7445.AM2011-4284