INDIVIDUAL RESEARCHERC. Michael DiPersio , Ph.D.
Education1991 - Ph.D. from Brown University
A long-term goal of our laboratory is to identify novel molecular targets for therapeutic strategies to inhibit invasive tumor growth and metastasis. In the epidermis of the skin, epithelial cells adhere to a specialized extracellular matrix (ECM) that prevents them from migrating into adjacent tissues. Cell adhesion to the ECM is also required for epithelial cell survival, since loss of adhesion leads to apoptotic cell death. During skin tumorigenesis, transformed epithelial cells secrete matrix metalloproteases, such as MMP-9, which can promote tumor growth and cell invasion by both degrading the ECM and liberating ECM-bound growth factors. In addition, invasive cancer cells become resistant to apoptosis, enhancing their ability to survive as they metastasize to distal tissues. Integrins are the major receptors for cell adhesion to the ECM, and some integrins can transmit signals into the cell that regulate MMP gene expression, cell migration, and cell survival. A major focus of our laboratory is on defining these integrin-mediated signal transduction pathways. Integrin α3ß1 provides a useful model for our studies, since this integrin is expressed in many cancer cell types and has been implicated in promoting carcinoma growth and invasion. We have established "MK" cell lines from epidermis of mice that lack integrin α3ß1, due to null mutation of the α3 gene, and from normal mice as controls. We have also established several variants of these MK cell lines representing different stages of the cellular transformation process. Through comparative analyses of these cell lines, we have determined that integrin α3ß1 plays important roles in MMP-9 gene expression (Iyer et al., 2005), in regulating cell migration (Choma et al., 2004), and in promoting cell survival (Manohar et al., 2004). We are using adenoviral/retroviral constructs and pharmacological inhibitors to perturb focal adhesion kinase (FAK) and other key intracellular signaling proteins to determine their importance in integrin-mediated MMP-9 gene expression, cell migration, and cell survival. In addition, we are developing several in vivo tumor models in order to link integrin-mediated signaling pathways with tumor growth, progression, and cell invasion, and to determine whether perturbation of these pathways is an effective way to inhibit invasive tumor growth. In one such model, we are testing the tumorigenic and metastatic potential of the MK cell lines following injection into immuno-compromised mice. In a second approach, we are studying tumor growth in mice that harbor mutations in genes for key integrins and/or signaling proteins.
- DiPersio CM, Shao M, Di Costanzo L, Kreidberg J, and Hynes RO. (2000) Mouse keratinocytes immortalized with large T antigen acquire a3ß1 integrin-dependent secretion of MMP-9/gelatinase B. J Cell Sci 113:2909-2921.
- Choma DP, Pumiglia K, and DiPersio CM. (2004) Integrin a3ß1 directs the stabilization of a polarized lamellipodium in epithelial cells through activation of Rac1. J Cell Sci 117:3947-3959.
- Manohar A, Shome SG, Lamar J, Stirling L, Iyer V, Pumiglia, K, and DiPersio CM. (2004) a3;ß1 integrin promotes keratinocyte cell survival through activation of a MEK/ERK signaling pathway. J Cell Sci 117:4043-4054.
- Iyer V, Pumiglia K, and DiPersio CM. (2005) a3ß1 integrin regulates MMP-9 mRNA stability in immortalized keratinocytes: a novel mechanism of integrin-mediated MMP gene expression. J Cell Sci 118:1185-1195.