Proteolysis is an intrinsic component of cutaneous wound repair and several matrix metalloproteinases have been shown to participate in various stages of this process. Therefore, we investigated the expression of a novel metalloproteinase, collagenase-3 (MMP-13), in normally healing cutaneous wounds and chronic venous ulcers. MMP-13 was expressed abundantly by fibroblasts deep in the chronic ulcer bed but was not detected in epidermis and all the acute wounds. The spatial expression of MMP-13 differed from that of collagenase-1 (MMP-1), which was prominently expressed by migrating keratinocytes and dermal cells located just beneath the wound surface. Northern blot hybridization did not reveal expression of MMP-13 by fibroblasts cultured on tissue culture plastic. In accordance with our in vivo findings, however, fibroblasts grown in a collagen gel produced MMP-13 mRNA abundantly. Our results suggest that MMP-13 can be induced in skin during wound repair after altered cell-matrix interactions. Although both MMP-1 and MMP-13 have the unique ability to degrade fibrillar collagens, their regulation and role during wound repair seem different. Collagenase-1 is critical for re-epithelialization, and MMP-13 most likely plays a role in the remodeling of collagenous matrix in chronic wounds.

Summary Since proteolysis of the dermal collagenous matrix and basement membranes is required for local invasive growth and early metastasis formation of cutaneous melanomas, we have analysed the activities/expression levels of certain metalloproteinases in melanomas and cultured melanoma cells by in situ hybridization and Northern analysis. In addition to collagenases-1 and -3 that have been implicated in invasive growth behaviour of various malignant tumours, we analysed the levels of 72-kDa gelatinase and its activators MT1-MMP and TIMP-2 in cultured melanoma cells. The lesions examined included three cases of lentigo maligna and 28 cases of Clark grade I-V melanomas. The premalignant as well as the grade I tumours were consistently negative for collagenase-1 and -3 and TIMP-1 and -3. The collagenases were predominantly expressed in the cancer cells of Clark grade III and IV tumours. TIMP-1 and -3 were abundantly expressed in the cancer and/or stromal cells of grade III and IV melanomas, while TIMP-2 protein was detected also in melanomas representing lower invasive potential. Northern analysis of seven melanoma cell lines showed that the expression of collagenase-1 and TIMPs-1 and -3 was associated with 72-kDa gelatinase positivity. All melanoma cell lines were positive for MTI-MMP and TIMP-2 mRNAs. Our results suggest that overexpression of collagenases-1 and -3 and TIMPs -1 and -3 is induced during melanoma progression. Expression of TIMPs may reflect host response to tumour invasion in an effort to control MMP activity and preserve extracellular matrix integrity. Keywords: MMP; cell invasion; angiogenesis; gelatinase 733British Journal of Cancer (1999) 80(5/6), 733-743 © 1999 Cancer Research Campaign Article no. bjoc.1998 Received 10 September 1998 Revised 3 December 1998 Accepted 3 December 1998Correspondence to: UK Saarialho-Kere type I, II and III collagens. Furthermore, MMP-13 is gelatinolytic and type IV collagenolytic (Knäuper et al, 1996, and MMP-1 has also some activity against full-length type IV collagen (Collier et al, 1988). Our objective was to determine the expression patterns and cellular localization of these MMPs during melanocytic tumour progression. Furthermore, as imbalance between TIMPs and MMPs is an important factor in tumour invasion, the expression levels of collagenase inhibitors TIMP-1 and -3 were also examined. Our results suggest that the induction of MMPs-1 and -13 and their tissue inhibitors is a late event in melanocytic tumour progression, and that these enzymes are involved in the regulation of melanoma invasion. MATERIALS AND METHODS Tissue specimensFormalin-fixed, paraffin-embedded specimens were obtained from the Department of Dermatopathology, Helsinki University Central Hospital, Helsinki, Finland. Invasion levels of the melanomas were determined by Clark's classification: level I with confinement of the malignant melanoma cells to the epidermis and its appendages; level II with extension to the papillary dermis so that only a few melanoma cells extended to the int...

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The present study was carried out to characterize the patterns of expression of matrix metalloproteinases or their tissue inhibitor (TIMP-1) in normally healing, acute vs. chronic, skin wounds. In situ hybridization was performed to localize collagenase, stromelysin-1, stromelysin-2, matrilysin, urokinase plasminogen activator (uPA) and TIMP-1 mRNAs in 14 chronic venous ulcers and 10 normally healing wounds, representing different time points after wounding. Surgical wounds, made in piglets harvested at several time points, were studied as controls. Collagenase, stromelysin-1 and -2, as well as uPa, were expressed in keratinocytes in both acute and chronic wounds, while epithelial TIMP-1 mRNA was not detected in any chronic wound biopsies studied. However, TIMP-1 was expressed at the epithelial edges of both acute human and pig wounds. Our results suggest that the balance between metalloenzymes and their inhibitor TIMP-1, is disturbed, in poorly healing wounds.