Proteolytic Enzymes in Tumor Invasion and Degradation of Host Extracellular Matrices

Abstract

A fact widely recognized by clinical oncologists is that rather than the primary tumor, the secondary metastatic tumor(s) usually leads to the lethality of human malignant disease (1–4). Tumor invasion, the destructive penetration of surrounding normal tissues by malignant cells, is an important feature of the metastatic spread and dissemination of cancer (5–9). Invasive tumor cells must penetrate a number of host extracellular barriers and matrices, including basement membranes, at several stages of tumor metastasis. Investigation of the biochemical mechanisms involved in tumor invasion and degradation of host extracellular matrices have indicated that proteolytic enzymes play a role in these processes (5–13). This chapter will review the role of various proteolytic enzymes in the destruction of several host matrices and their specific components during tumor invasion and metastasis. In addition, the potential significance of matrix degradation by proteolytic enzymes during tumor invasion to the diagnosis and therapy of human metastatic disease will be discussed.