Introduction: Positron Emission Tomography (PET) has revolutionized the diagnostic and imaging fields in cancer research. PET has opened new avenues in the pre-clinical study of radiotracers and radio-therapeutic compounds of which the full potentials are yet to be explored. To date 18F-Fluoro-Deoxy-Glucose1 (18F-FDG) is the most widely used radiotracer for PET imaging. The success of 18F-FDG is due to the existence of several trans-membrane proteins responsible for the facilitated transport of glucose. A related protein is a specific fructose selective trans-membrane transporter (GLUT 5) that has been observed to be over-expressed by some types of cancer cells suggesting that D-fructose is utilized by these cancer cells for energy production. Thus labeled D-fructose derivatives are potential candidates for selective PET imaging for cancer cells similar to 18F-FDG in active cells. Aim: The aim of this study was to investigate the effect of D-fructose on GLUT 5 positive and negative cell cultures and to evaluate the feasibility of GLUT 5 as a target for PET imaging of breast cancer. Objectives: The following were investigated: <ul> i. The extent of expression of GLUT 5 in three cancer cell lines: breast cancer cells (MCF-7), Baby Hamster Kidney cells (BHK) and cervical epithelial carcinoma cells (Hela). ii. The colony formation potential of D-fructose enriched medium (glucose-free) and its effect on proliferation of the investigated cell lines. iii. The effect of anti-GLUT 5 antibodies on the proliferation of breast cancer cells in vitro. iv. The synthesis and characterization of a non-radioactive fluorinated D-fructose derivative (1-deoxy-fluoro–D-fructose) </ul> Results: D-fructose was observed to mediate cell growth in MCF-7 cell lines but not in Hela and BHK cell lines. Glucose stimulated significantly greater cell proliferation than D-fructose for all 3 cell lines but more noticeably for the Hela (p<0.001) and BHK (p=0.0110) cell lines at all tested concentrations. Cell growth of MCF-7 cell lines where only D-fructose was present suggests a role for the highly expressed fructose specific transporter (GLUT 5) in the use of D-fructose for energy production and cell growth by these breast cancer cells. No significant differences were observed in the ability of D-fructose enriched medium to induce 3D colony formation among the three cell lines studied (p>0.05) suggesting that D-fructose is not linked directly with aggressive carcinogenesis in these cell lines despite the observed evidence of D-fructose involvement in cell proliferation and energy consumption. Anti-GLUT 5 antibodies did not show an inhibitory effect on MCF-7 cell proliferation at concentration up to 1 μg/ml (1:1000) despite these cells high expression of GLUT 5. GLUT 5 is highly expressed by MCF-7 but not by Hela and BHK cell lines making it an important selective target for imaging of this type of breast cancer and a possible therapeutic target for antibody targeted therapy of breast cancer. A chemical reaction sequence for the synthesis of 1-deoxy-fluoro–D-fructose (1-FDF) was carried out and an acceptable yield for an isotope labeling friendly reaction sequence was obtained and the product chemically characterized. Conclusion: The D-fructose transporter GLUT 5 shows potential for possible application with PET imaging of breast cancer. Isotope labeled 1-FDF can be synthesized in good yield and should be the object of further studies such as development of an automated synthesis module for its radio-labeled derivative as well as pre-clinical animal and human studies. Copyright / Dissertation (MSc)--University of Pretoria, 2013. / Pharmacology / unrestricted
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:up/oai:repository.up.ac.za:2263/29737 |
| Date | 23 November 2012 |
| Creators | Kyalangalilwa, Mulondani Nicolas |
| Contributors | Dr A D Cromarty, kyamunigy@yahoo.fr |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Dissertation |
| Rights | © 2012, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria |
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