Matrix-metalloproteinases in bronchopulmonary carcinomas

Matrix metalloproteinases (MMPs) represent a group of enzymes involved in t he degradation of most of the components of the extracellular matrix and th erefore participate in tumoural invasion. MMPs, especially gelatinases A an d B, MT1-MMP, the activator of gelatinase A, and stromelysin-3 were found o verexpressed in many cancers including bronchopulmonary carcinomas. In vivo observations revealed that fibroblasts are the principal source of product ion of MMPs. Some of these enzymes such as MT1-MMP and stromelysin 3, displ ayed a focal stromal localisation near preinvasive and invasive tumour clus ters. Furthermore, some tumour cell lines were shown to stimulate the expre ssion of MT1-MMP by fibroblasts. All these in vivo and in vitro results sug gest that certain tumour cells produce diffusible factors which could influ ence the MMP stromal expression. Among these factors, the TCSF (Tumor Colla genase Stimulatory Factor) which is known to upregulate some MMPs in vitro could be a good candidate for this stromal regulation, since it is produced by bronchial tumour cells in vivo. In this review, we address such a coope ration between tumour and stromal cells for the production of MMPs and emph asize their necessity for tumoural progression in bronchopulmonary carcinom as.