Development of a CA125-mesothelin cell adhesion assay as a screening tool for biologics discovery.

Preventing peritoneal implantation of ovarian carcinoma cells could prolong patient remission and survival. CA125 is expressed on most ovarian cancer cells and was reported to be a ligand of mesothelin, a peritoneal protein. We developed a cell adhesion assay with CA125-expresser ovarian cancer cells and human mesothelin-transfected cells and we confirmed that CA125 and mesothelin mediate cell attachment. We also showed that this assay supplies a high-throughput screening system for reagents able to block CA125/mesothelin-dependent cell attachment with a sensitive quantitative readout. We finally demonstrated that a mesothelin chimeric protein and anti-CA125 antibodies block CA125/mesothelin-dependent cell attachment.