Matrix metalloproteinases (MMPs) in oral carcinomas
1University of Oulu, Faculty of Medicine, Institute of Dentistry, Department of Oral and Maxillofacial Surgery
|Online Access:||PDF Full Text (PDF, 2.3 MB)|
|Persistent link:|| http://urn.fi/urn:isbn:9514277309
|Publish Date:|| 2005-05-18
|Thesis type:||Doctoral Dissertation
|Defence Note:||Academic Dissertation to be presented with the assent of the Faculty of Medicine, University of Oulu, for public discussion in Auditorium 1 of the Institute of Dentistry, on May 28th, 2005, at 12 noon
Professor Veli-Pekka Lehto
Professor Ismo Virtanen
Matrix metalloproteinases, MMPs, are a family of enzymes capable of modulating connective tissue components. The expression of several MMPs is increased in oral squamous cell carcinomas (OSCCs). They are assumed to have an important role in the development and progression of OSCCs. However, the exact role and mechanism of the regulation of MMPs in malignant transformation are still largely unknown.
In this study, tumour-associated trypsin-2 (TAT-2) was detected in OSCC tissue sections, and its role in MMP-2 and -9 regulation in carcinoma cells was evaluated. The TAT-2 gene was transfected into two different OSCC cell lines and one immortalized oral epithelial cell line. In TAT-2-transfected cells, MMP-9 activation increased OSCC cell invasion in chicken chorionallantoic membrane assay. Increased intravasation was prevented by tumour-associated trypsin inhibitor or specific gelatinase-inhibiting CTT-peptide. TAT-2 also converted MMP-1, -8, -13 and -3 into smaller molecular weight forms in vitro. However, TAT-2-transfected OSCC cells showed no conversion. TAT-2 was demonstrated to degrade powerfully type I collagen into small fragments in vitro. The cell surface receptor αvβ6 integrin is strongly up-regulated in OSCCs. By using β6-transfected OSCC cells, it was demonstrated that αvβ6 integrin down-regulates MMP-13 expression. However, this integrin did not regulate other collagenases or TIMP-1. β6-transfected cells invaded more efficiently through the basement membrane matrix, but their migration through type I collagen remained unchanged. MMP-8 expression was detected for the first time in head and neck squamous cell carcinoma (HNSCC) cell lines and corresponding cultured dermal and tumour fibroblasts. The localization of MMP-8 in HNSCC was determined by immunohistochemical stainings and in situ hybridization. MMP-8 production levels in carcinoma cells were faint and sporadic in HNSCCs sections. Ninety-two primary mobile tongue SCCs were subjected to MMP-8 immunohistochemical staining, and the staining results were compared to survival rates. MMP-8 was associated with improved disease-free survival in females but not in males.
Acta Universitatis Ouluensis. D, Medica