| Popis: |
Collagen XVII (BP180) is a transmembrane component of hemidesmosomes, which connect basal keratinocytes to the basement membrane. The extracellular domain of collagen XVII is proteolytically shed from the cell surface and released to the extracellular matrix. Apart from its function in epithelial cell adhesion, collagen XVII has been suggested to participate in keratinocyte motility. The collagen XVII expression pattern was studied in wounds of oral mucosa and in epithelial tumors. During re-epithelialization, collagen XVII was expressed in the keratinocytes distal to the wound edge, but not in the leading cells of the epithelial tip. Collagen XVII upregulation was observed in moderate/severe dysplasias of oral mucosa. In follicular ameloblastomas and basal cell carcinomas, collagen XVII expression was reduced in peripheral cells, whereas cytoplasmic staining was detected in central tumor cells. Tongue squamous cell carcinomas showed increased collagen XVII expression in grade II/III tumors, particularly in areas of invasive growth. The results suggest a correlation between overexpression of collagen XVII and the invasive potential of the tumor. For the first time, the role of collagen XVII in the regulation of malignant migration was explored. The presence of COL15, the cell adhesion domain of collagen XVII, induced migration of tongue squamous cell carcinoma cells in transmigration assays. Experiments with specific function-blocking integrin antibodies revealed that the promigratory function of COL15 is mediated by αv and α5 integrins. The role of the matrix metalloproteinase (MMP) family of proteolytic enzymes in wound re-epithelialization was studied in a transgenic mouse model. In these mice, a specific inhibitor of MMPs, TIMP-1, was overexpressed in cells that normally produce MMP-9. The healing of cutaneous wounds was found to be significantly delayed, but not prevented, due to the impaired ability of keratinocytes to migrate to the wound area. These results suggest that collagen XVII may participate in epithelial tumor progression and invasion by promoting migration of tumor cells. Based on the present study, epithelial cell-derived MMPs play a significant role in the migration of wound keratinocytes during re-epithelialization. |
