UNIVERSITY OF MALTA
LIFE SCIENCE RESEARCH SEMINARS
Web: http://www.um.edu.mt/events/scisem/
Email: scisem@um.edu.mt
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Enhancing chemotherapy effectiveness
Pierre Schembri-Wismayer
Department of Anatomy, University of Malta
2340 2797, 99859159
21319527
pierre.schembri-wismayer@um.edu.mt
14 February 2011
Abstract
The Opuntia extract, TEX-OE®, stimulates the production of inducible heat shock
proteins (HSPs) in cells which help in minimizing the negative effects caused by
stress stimuli. The main aim of this study was to determine whether pre-conditioning
of normal and cancerous cells with TEX-OE® increased their survival after being
exposed to a chemical stress stimulus – chemotherapy.
The crude extract of TEX-OE® was applied to two non-cancerous types of cells,
HaCaT and peripheral blood mononuclear cells (PBMC), as well as two cancerous
cell lines, HeLa and COLO 679, all of which were treated with a chemotherapeutic
stress stimulus.
A number of preliminary tests to identify suitable experimental parameters were first
carried out. Four chemotherapeutic drugs, namely Vincristine, Cytarabine, Cisplatin
and Doxorubicin were each tested on the four different types of cells to identify the
extent of cytotoxicity in each case. The most effective TEX-OE® conditions with
regards to concentration and exposure time were determined. The final preliminary
test was carried out to identify which chemotherapeutic drug‟s cytotoxicity was
reduced the most by preconditioning the cells with TEX-OE®.
Based upon the results of the above preliminary tests, the appropriate experimental
conditions were set and the four different types of cells were preconditioned for 6
hours with a concentration of 200μg/mL of TEX-OE®. The selected stress stimulus,
cytarabine, was then applied to the cells for a further 48 hours. All tests were carried
out by means of the MTT assay which measures viable cell number as a function of
mitochondrial dehydrogenase activity.
TEX-OE® was found to play a role in reducing the cytotoxic effect of the
chemotherapeutic drug in all cell types. It was most effective on the peripheral blood
mononuclear cells, reducing the cytotoxicity of cytarabine by a maximum of 38%.
This research study therefore gives insight to the possible role of TEX-OE® in
assisting with minimising the negative effects of chemotherapy.