Remodeling of dermal connective tissue is a feature of growth and development and conversely, destruction of this extracellular matrix is characteristic of neoplastic and inflammatory disorders. Degradation of the structural macromolecules of the dermal extracellular matrix is mediated by a metalloproteinase family which includes interstitial collagenase, gelatinase, and stromelysin. These degradative enzymes are in turn regulated by a proteinase inhibitor, Tissue Inhibitor of MetalloProteinases or TIMP. If the actions of the metalloproteinases and TIMP truly play crucial roles in matrix degradation and remodeling, then studies to determine their distribution, metabolism and regulation by products of epithelial and dermal cells should be useful in understanding connective tissue related disorders. Poorly characterized factors from skin cancers and normal keratinocytes that are capable of modulating production of metalloproteinases and TIMP will be isolated and characterized. Concurrent studies of specific and well-defined cytokines relevant to skin biology (Epidermal growth factor, Transforming growth factors a,b, Tumor necrosis factor, Interleukin-1 and basic growth factor, Transforming growth factors a,b, Tumor necrosis factor, Interleukin-1 and basis Fibroblast growth factor) will be used in model systems. The specific effects of the cytokines will be further examined using functional, immunological, biosynthetic and mRNA quantitation methods. To establish the role of metalloproteinases and TIMP in matrix degradation, the distribution of these proteins will be studied in normal human skin and a panel of basal cell carcinomas displaying a spectrum of connective tissue alterations. Additionally, in situ hybridization techniques will be employed using cDNA probes to collagenase and TIMP to establish which cells involved in the tumor- extracellular matrix interaction actually contain specific mRNAs. To independently address the role of TIMP in neoplastic invasion and metastasis, regulated expression vectors containing the TIMP sequence will be placed in selected murine tumor lines. Alterations in the biological behavior of these cells when placed in a murine host should increase our understanding of both TIMP and metalloproteinase activities in this process. These studies will help to identify the sites of production of metalloproteinases and TIMP in human skin and provide insights into the normal and abnormal physiology of connective tissue remodeling.
