title: MMP25 (MT6-MMP) is highly expressed in human colon cancer, promotes tumor growth, and exhibits unique biochemical properties.
abstract: MMP25 (MT6-MMP) is one of the two glycosylphosphatidylinositol-anchored matrix metalloproteinases (MMPs) that have been suggested to play a role in pericellular proteolysis. However, its role in cancer is unknown, and its biochemical properties are not well established. Here we found a marked increase in MT6-MMP expression within in situ dysplasia and invasive cancer in 61 samples of human colon cancer. Expression of MT6-MMP in HCT-116 human colon cancer cells promoted tumori-genesis in nude mice. Histologically, the MT6-MMP-expressing tumors demonstrated an infiltrative leading edge in contrast to a rounded leading edge in vector control tumors. Biochemical and biosynthesis analyses revealed that MT6-MMP displayed on the cell surface exists as a major form of 120 kDa that likely represents enzyme homodimers linked by disulfide bonds. Upon reduction, a single 57-kDa active MT6-MMP was detected. Interestingly, neither membrane-anchored nor phosphatidylinositol-specific phospholipase C-released MT6-MMPs were found to be associated with tissue inhibitor of metalloproteinases (TIMPs) and did not activate pro-gelatinases (pro-MMP-2 and pro-MMP-9) even in the presence of exogenous TIMP-2 or TIMP-1. A catalytic domain of MT6-MMP was inhibited preferentially by TIMP-1 (K(i) = 0.2 nm) over TIMP-2 (K(i) = 2.0 nm), because of a slower association rate. These results show that MT6-MMP may play a role in colon cancer and exhibit unique biochemical and structural properties that may regulate proteolytic function at the cell surface.
authors.affiliation: Department of Pathology and Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Sun
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Weber
authors.forename: Anjum
authors.initials: A
authors.lastname: Sohail
authors.forename: M Margarida
authors.initials: MM
authors.lastname: Bernardo
authors.forename: Marta
authors.initials: M
authors.lastname: Toth
authors.forename: Huiren
authors.initials: H
authors.lastname: Zhao
authors.forename: Jerrold R
authors.initials: JR
authors.lastname: Turner
authors.forename: Rafael
authors.initials: R
authors.lastname: Fridman
mesh_terms: D000230:Adenocarcinoma; D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D002455:Cell Division; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000201:enzymology / Q000473:pathology; D015179:Colorectal Neoplasms / Q000201:enzymology / Q000473:pathology; D004847:Epithelial Cells; D058851:GPI-Linked Proteins; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D000882:Haplorhini; D006801:Humans; D053504:Matrix Metalloproteinases, Membrane-Associated / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000494:pharmacology; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000494:pharmacology; D014162:Transfection
chemical_list: D058851:GPI-Linked Proteins; D017261:Glycosylphosphatidylinositols; D009363:Neoplasm Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D053504:Matrix Metalloproteinases, Membrane-Associated; C403928:matrix metalloproteinase 25