Calpain activity and expression in human colonic tumors

Abstract

Families of cysteine proteases which are activated by Ca2+ are known ascalpains. These enzymes can contribute to the metastatic behavior of certaintumors. In particular, we have found from Western Blotting and immunohistochemistrythat the activity and expression of m-calpain is higher in colorectaltumors than non-malignant colonic mucosa. Furthermore, the expression ofcalpastin and high molecular weight calmodulin-binding protein, which areinhibitors of calpains, is reduced in colon cancers. These findings are of greatimportance in the design and development of anticancer drugs as well asproviding diagnostic value as an indicator of the development of colorectalcancer. This chapter is devoted principally to the discoveries in our laboratoriesof calpain and its inhibitors in relation to human colonic neoplasms.