Detection of Serum Lysophosphatidic Acids Using Affinity Binding and Surface Enhanced Laser Deorption/Ionization (SELDI) Time of Flight Mass Spectrometry

摘要

We proposed to apply novel technologies to the development of an approach suitable to detect plasma and serum lipid levels for screening for ovarian cancer in high and low risk women. The first of these is a novel approach to the development of antibodies, which will recognize specific phospholipids and lysophospholipids present in ovarian cancer patients and the second of these is SELDI tof mass spectroscopy. These two technologies will be merged with powerful computing tools to develop approaches capable of detecting ovarian cancer at an early, curable stage. This approach will further benefit from the expertise of the Mills laboratory (LPA screening, SELDI tof) with that of the Prestwich laboratory (lipid synthesis and antibody development). We have completed the studies proposed in the application. We have demonstrated that SELDI mass spectroscopy using nonspecific and affinity matrices has the ability to detect and characterize model lysopholipids including LPC, LPA, S1P and LPS present in plasma and serum. This assay is applicable to relatively large volumes of plasma and serum >2ml. We have also demonstrated that additional mass spectroscopy approaches have a greater degree of sensitivity and specificity when compared to SELDI mass spectroscopy. We proposed to develop and analyze lipid specific antibodies. We have analyzed anti-S1P antibodies as both a theragnostic and a diagnostic using a sensitive ELISA approach. LPA antibodies appear to block the growth of hybridomas due to blocking LPAmediated survival. We thus took an interim step of identifying novel LPA binding proteins as alternative affinity reagents. We also developed novel LPA receptor selective agonists that would bypass the inhibitory activity of the LPA antibody. With these in hand, we have immunized mice with LPA constructs and have developed very high titer anti-LPA antibodies.