title: Differential expression and localization of TIMP-1 and TIMP-4 in human gliomas.
abstract: Studies have suggested that an imbalance of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) may contribute to the malignant phenotype of gliomas. In this study, we have undertaken a detailed analysis of expression of the TIMP family in normal human brain and malignant gliomas at both the mRNA and protein level. Reverse transcription-PCR (RT-PCR) analyses of total RNA from surgical tumour specimens revealed unique expression patterns for the 4 members of the TIMP family, with TIMP-1 and -4 showing positive and negative correlations, respectively, with glioma malignancy. By RT-PCR, TIMP-2 and TIMP-3 expression did not change with tumour grade. In situ hybridization localized TIMP-1 to glial tumour cells and also to the surrounding tumour vasculature. TIMP-4 transcripts were predominantly localized to tumour cells, though minor expression was found in vessels. Recombinant TIMP-4 reduced invasion of U251 glioma cells through Matrigel, and U87 clones overexpressing TIMP-4 showed reduced invasive capacity in vitro. TIMP-4, but not TIMP-1, blocked Membrane Type-1-MMP-mediated progelatinase-A (MMP-2) activation in human umbilical vein endothelial cells. The differential expression and localization of individual TIMPs may contribute to the pathophysiology of human malignant gliomas, particularly with regard to tumour vascularization.
authors: Department of Biochemistry and Molecular Biology, The University of Calgary, Alberta, Canada.
authors: L L
authors: LL
authors: Groft
authors: H
authors: H
authors: Muzik
authors: N B
authors: NB
authors: Rewcastle
authors: R N
authors: RN
authors: Johnston
authors: V
authors: V
authors: Knäuper
authors: M A
authors: MA
authors: Lafleur
authors: P A
authors: PA
authors: Forsyth
authors: D R
authors: DR
authors: Edwards
mesh_terms: D001932:Brain Neoplasms / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004789:Enzyme Activation / Q000187:drug effects; D004792:Enzyme Precursors / Q000378:metabolism; D018093:Gelatinases / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D005910:Glioma / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D017403:In Situ Hybridization; D008666:Metalloendopeptidases / Q000378:metabolism; D009361:Neoplasm Invasiveness; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis* / Q000235:genetics; D019714:Tissue Inhibitor of Metalloproteinases / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D000097792:Tissue Inhibitor of Metalloproteinase-4
chemical_list: D004792:Enzyme Precursors; D018093:Gelatinases; D008666:Metalloendopeptidases; D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D019714:Tissue Inhibitor of Metalloproteinases; D000097792:Tissue Inhibitor of Metalloproteinase-4; C069860:progelatinase