PROTEASES AND THEIR INHIBITORS IN HUMAN BRAIN-TUMORS - A REVIEW

Proteases such as matrix metalloproteinases (MMPs), cysteine-and serin e-proteinases are capable of degrading extracellular matrix and baseme nt membranes and have been implicated in human brain tumours. MMPs are a homologous family of zinc-dependent proteases. Within this group, a ttention has been focused on the gelatinases (MMP-2 and MMP-9) which a re thought to play an important role in tumour progression. The cystei ne proteinases which have received most attention in relation to tumou r progression are cathepsin B (CB) and to a lesser extent cathepsin L (CL). Among the serine proteinases, urokinase plasminogen activator an d its receptor have been the subject of much investigation. In the pre sent review, evidence from current literature on the possible role or significance of serine- and cysteine-proteinases and MMPs and their in hibitors in human brain tumours is discussed with special reference to gliomas. Although direct evidence is reported for MMPs and serine pro teinases to support their role in glioma invasion much of the evidence for the involvement of cysteine proteinases remains circumstantial.