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

A preliminary analysis of immunoprecipitation followed by Western Blotting (WB) shows corin and TLP
precipitate at the same level (approximately 50 KDa) and are recognized by the same antibodies. In
parallel the tests of immunoprecipitation were improved by the use of cell extracts derived from lung
cancer cells A549 and NCI-H23 with the aim of obtaining a precipitate containing only the TLP. In fact
the partial amino acid sequence of TLP shows a high homology with the sequence of human corin
(only one amino acid 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 over expresses corin,
shows several bands analysed on SDS-PAGE that are equivalent to the bands (about 50-100 KDa)
observed in the WB analysed by anti-TLP.