Calpain Dependent Lung Cancer Cell Migration and Invasion

The purpose of this research is to investigate the mechanisms involved in the migration and metastasis of lung tumor cells. The hypothesis to be tested is that the action of a protease termed calpain (Cp), is integral to lung cancer cell migration, invasion and metastasis. Proteases are enzymes that cleave proteins and as a consequence are critical for the regulation of cell function. Cp and its regulatory molecules, calpastatin (Cs) and a regulatory subunit (collectively referred to as the Cp/Cs network) participate in a number of cellular functions including the regulation of normal and malignant cell movement. The migration and invasion of tumor cells into adjacent tissue sites or the metastasis to distant sites, such as lymph nodes, is modulated in part by receptors on these cells, which bind to their ligands on the extracellular matrix (ECM). The experiments described in the first aim of this grant will examine the role of the Cp/Cs network in assays designed to quantitate the adhesion and migration of lung cancer cells to the ECM. Thus, one component of the first aim of this proposal will be to investigate the role of the Cp/Cs network in the adhesion and migration of a lung cancer cell line (A-549) on the ECM protein laminin. In addition, the role of the Cp/Cs network on the ability of this lung cancer cell line to invade into the ECM will be assessed. Results from these studies will establish the importance of the Cp/Cs network in lung cancer cell migration and metastasis and pave the way for the second aim of this grant. This aim is designed to investigate mechanistically how the Cp/Cs network can regulate the adhesion, shape change and migration of A-549 binding to the ECM. The hypothesis to be tested is that the Cp/Cs network translocates to subcellular organelles in the A- 549 cells and this is required for regulation of cell migration and metastasis. These studies will use microscopic and biophysical techniques to probe for the intracellular locations ofCp and its regulatory proteins in A-549. Experiments will also be done to determine how Cp and its regulatory proteins bind to these locations and what proteins are cleaved by Cpo The collective results from these studies will prove useful in developing new therapeutic strategies to prevent the growth and spread of lung cancer.