title: A novel strategy to tag matrix metalloproteinases-positive cells for in vivo imaging of invasive and metastatic activity of tumor cells.
abstract: Matrix metalloproteinases (MMPs) are endopeptidases responsible for degrading the extracellular matrix (ECM) and remodeling tissue in both physiological and pathological processes. MMP2 and membrane-type 1 MMP (MT1-MMP) have been associated with tumor invasion, metastasis and angiogenesis; therefore, a molecular imaging strategy assessing their activity may help to predict the malignancy of tumors. Here, we established a novel method of specifically tagging the surface of MMP2- and MT1-MMP-positive cells, and applied it to the development of an optical imaging probe. We constructed a protein-based probe composed of a glutathione-S-transferase (GST)-tag (Inhibitory [I]-domain), a polypeptide as a specific substrate for both MMP2 and MT1-MMP (Cleaved [C]-domain), a transmembrane domain of the epidermal growth factor receptor (Transmembrane [TM]-domain), and DsRed2 (Fluorescent [F]-domain). In vitro experiments clearly demonstrated that, after the probe was cleaved at the C-domain by the MMPs, the resultant TM-F-domain was inserted into the cellular membrane. Optical imaging experiments in vivo demonstrated that the probe was cleaved and specifically remained in tumor xenografts in a MMP-dependent manner. These results indicate that the release of the I-C-domain through the proteolytic cleavage of the C-domain by MMP2 and MT1-MMP triggers the tagging of cellular membranes with the TM-F-domain. The present feasibility study opens the door to the development of a novel imaging probe for tumor malignancy using positron emission tomography as well as an optical imaging device.
authors.affiliation: Department of Radiation Medicine, Fourth Military Medical University, 17 Changle West Road, Xi'an, Shaanxi 710032, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhao
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Harada
authors.forename: Yuji
authors.initials: Y
authors.lastname: Teramura
authors.forename: Shotaro
authors.initials: S
authors.lastname: Tanaka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Itasaka
authors.forename: Akiyo
authors.initials: A
authors.lastname: Morinibu
authors.forename: Kazumi
authors.initials: K
authors.lastname: Shinomiya
authors.forename: Yuxi
authors.initials: Y
authors.lastname: Zhu
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Hanaoka
authors.forename: Hiroo
authors.initials: H
authors.lastname: Iwata
authors.forename: Hideo
authors.initials: H
authors.lastname: Saji
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002477:Cells / Q000378:metabolism; D022082:Cellular Structures / Q000378:metabolism; D003952:Diagnostic Imaging; D010450:Endopeptidases / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D008566:Membranes / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D057054:Molecular Imaging; D010455:Peptides; D012878:Skin Neoplasms
chemical_list: D010455:Peptides; D066246:ErbB Receptors; D010450:Endopeptidases; D020782:Matrix Metalloproteinases; D020778:Matrix Metalloproteinase 2; D020781:Matrix Metalloproteinase 1; D053511:Matrix Metalloproteinase 14