COMPARATIVE PROFILING BY PROTEOMICS AND ZYMOGRAPHIC ACTIVITIES OF TUMORAL AND NON TUMORAL CELL LINES

The extracellular matrix (ECM) underlying epithelial tissues is involved in the maintenance of cell polarity and homeostasis. ECM is a dynamic structure under the regulated remodeling of its components. The major enzymes responsible of matrix degradation are the matrix metalloproteinases (MMPs), a well known family of zinc-dependent endopeptidases. Much attention has been focused on MMP-2 and MMP-9 because of their ability to degrade type IV collagen, a major constituent of basement membranes. A deregulated proteolysis of ECM molecules may cause the alteration of cell polarity and may contribute to the disruption of cell–cell and cell–ECM adhesions, promoting cancer progression. These alterations are responsible for a poor prognosis, and a positive correlation between the increase of MMPs and the degree of malignancy has also been observed FOR many tumor histotypes. To approach these issues on in vitro models, we performed a comparative study, between a couple of tumoral and non-tumoral mammary cell lines and a couple of thyroid cell lines derived respectively from a benign and malignant cancer. This experimental approach, based on scanning electron microscopy, on proteomic analysis and on gelatin zimography, highlighted a similar profiling of the two differential couples of cell lines: that is between malignant and non-malignant cells respectively, regardless of their histological origin. In particular, it was observed that the cell lines derived from aggressive cancers, when compared with their non-malignant counterpart, showed an increased secretion of MMPs, a cell shape highly pleomorphic and a higher expression of protein clusters potentially associated with invasion and metastasis. The analysis of the interactions between the expression of MMPs and of selected proteomic clusters have offered important indication on the complex network existing between neoplastic cells and their environment. The work was co-funded by the Italian 5x1000 to COBS.