Michael Thompson
Institute for Biomedical Engineering at the University of Toronto, Canada
Title: Towards early stage detection of ovarian cancer via lysophosphatidic acid as a biomarker
Biography
Biography: Michael Thompson
Abstract
The existing CA-125 assay for ovarian cancer has been used for many years but is widely regarded to be inadequate ,especially for detection of early development of the disease (stages I and II). Accordingly, there is an urgent requirement for a srreening assay that can detect the presence of ovarian or fallopian tube tumours at the early stage of the dieease via biomarker technology. Our technology involves the biomarker, lysophosphatic acid (LPA), which has clearly been shown to be present in the early stages of disease. Currently, there is no simple screening assay for this molecule in serum or blood. We are in the process of developing both a simple screening assay, and a biosensor technique specially desigend for the clinical biochemistry lab for LPA. The design of our assay is based upon the highly selective disruption of the binding of gelsolin to the protein actin by LPA, which is signalled via a rhodamine dye. We have studied the concentration-dependant break up of the gelsolin-actin-rhodamine complex at LPA concentrations of biological significance (1-50 micromolar). This chemistry has been shown to effective in serum. In order to produce a future assay, it is necessary to transfer the chemistry to a suitable material surface. This has been succesfully achieved by Ni- NTA linkers via their attachment to His tags on gelsolin (to plastic, silica and metal). For these surfaces we have developed nanoparticle technology (SiO2) that increases the surface area available for protein probe binding. To date we have demonstrated that LPA concentrations at sub- 20 micromolar concentration can be measured directly in human serum.