Noninvasive fluorescence monitoring for functional assessment of murine glioma treatment.

Abstract

Molecular optical imaging in vivo has potential for functional assessment of tumor tissue at the cellular and subcellular level. Advances in biological understanding of genomics and proteomics have increased the knowledge of possible cellular targets, allowing for functional detection, diagnosis, characterization and treatment monitoring of disease in situ. Yet current cancer treatment monitoring largely relies on structural imaging to quantify tumor size change, which can occur well after many identified molecular events have transpired. In this work, three model glioma cell lines were implanted orthotopically, including a green fluorescent protein (GFP) expressing rat gliosarcoma (9L-GFP), a human glioma (U251) and the GFP variant of this (U251-GFP). Tumor morphology was assessed through magnetic resonance imaging (MRI) and ex vivo pathology, which confirmed distinct phenotypic growth patterns of the three tumor models. The tumors were non-invasively monitored using an optical transmission spectroscopy system targeted at imaging tumor cell metabolism and EGFR activity with vii TABLE OF CONTENTS

Computed Tomography-guided Time-domain Diffuse Fluorescence Tomography in Small Animals for Localization of Cancer Biomarkers

“…phosphate buffer solution into the left cerebral hemisphere at a depth of approximately 2 mm below the surface of the brain. Use a Hamilton micro-syringe 18 and a blunt ended 27-gauge needle for cell implantation and insert the tip of the needle 3 mm from the outer surface of the skull and then withdraw 1 mm to create a pocket for the cells. 4.…”

Computed Tomography-guided Time-domain Diffuse Fluorescence Tomography in Small Animals for Localization of Cancer Biomarkers

“…The animal was inoculated orthotopically with a human glioma cell line (U251) in the left cerebral hemisphere and imaged 2 weeks later. The tumor was made to fluoresce by injecting a fluorescent tracer, IRDye 800CW-EGF (LI-COR Biosciences, Lincoln, NE) targeted to epidermal growth factor receptor, a cell membrane protein known to be overexpressed in the U251 tumor line and many other cancers 18 . A second, untargeted fluorescent tracer, Alexa Fluor 647 (Life Technologies, Grand Island, NY) was also injected to account for non-receptor mediated effects on the uptake of the targeted tracers to provide a means of quantifying tracer binding and receptor availability/density 27 .…”

Image reconstruction optimization and quantification for image-guided luminescent tomography

“…A series of athymic mice (n=30) were each implanted orthotopically with 1 million cells of a U251-GFP human glioma tumor line (supplied by Dr. Mark Israel, Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center). This tumor line was chosen because it is known to overexpress EGFR, which will be targeted (207,208). It was also chosen because the green fluorescent protein (GFP) signal can be measured ex vivo to provide tumor localization (209,210).…”