From Sequence of Tumor Liberated Protein (TLP) to Function and Potential Targets for Diagnosis and Therapy

From the first analysis of immuneprecipitation followed by Western Blotting (WB) Corin and TLP seem to precipitate at the same height ( approximately 50KDa) and are recognized by the same antibodies. In parallel we are improving the tests of immunoprecipitation by the use of cell extracts derived from lung cancer cells A549 and NCI-H23 with the aim to be able of obtaining a precipitate containing only the TLP. In fact the partial aminoacid sequence of TLP showes a high homology with the sequence of human Corin (only one aminoacid is different) and is present in lung cancer under different isoforms. It is known that human Corin is expressed mostly outside the cells and the protein extract derived from the extracellular medium and from the cells transfected with the plasmid, which overexpresses Corin, showes many more bands analyzed on SDS-PAGE that are equivalent to the bands (about 50-100 KDa) observed in the WB analyzed with anti-TLP.