title: In vitro irradiation of basement membrane enhances the invasiveness of breast cancer cells.
abstract: Following removal of the primary breast tumour by conservative surgery, patients may still have additional malignant foci scattered throughout the breast. Radiation treatments are not designed to eliminate all these residual cancer cells. Rather, the radiation dose is calculated to optimise long-term results with minimal complications. In a tumour, cancer cells are surrounded by a basement membrane, which plays an important role in the regulation of gene expression. Using an invasion chamber, we have shown that irradiation before cell plating of a reconstituted basement membrane (Matrigel; Becton Dickinson, Bedford, MA, USA) increased the invasiveness of the breast cancer cells MDA-MB-231. This radiation enhancement of invasion was associated with the upregulation of the pro-invasive gene matrix metalloproteinase (MMP)-2. The expression of membrane type 1 matrix metalloproteinase (MT1-MMP) and tissue inhibitor of metalloproteinase-2 (TIMP), which are required to activate the MMP-2, were also increased. Confirming the role of MMP-2 and MT1-MMP, radiation enhancement of cancer cell invasion was prevented by an MMP-2 inhibitor and an anti-MT1-MMP antibody. This study also demonstrated that radiation can potentially enhance the invasion ability by inducing the release of pro-invasive factors stored in the Matrigel. Conversely, no enhancement of invasiveness was observed with the low metastatic cell line MCF-7. This lack of invasiveness correlated with the absence of the MMP-2 activator MT1-MMP in the MCF-7 cells. Radiotherapy is an efficient modality to treat breast cancer which could be further improved by inhibiting the pro-invasive gene upregulated by radiation.
authors.affiliation: Department of nuclear medicine and radiobiology, Faculty of medicine and health sciences, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, Québec, Canada. Benoit.Paquette@USherbrooke.ca
authors.forename: B
authors.initials: B
authors.lastname: Paquette
authors.forename: C
authors.initials: C
authors.lastname: Baptiste
authors.forename: H
authors.initials: H
authors.lastname: Therriault
authors.forename: G
authors.initials: G
authors.lastname: Arguin
authors.forename: B
authors.initials: B
authors.lastname: Plouffe
authors.forename: R
authors.initials: R
authors.lastname: Lemay
mesh_terms: D000906:Antibodies / Q000276:immunology / Q000494:pharmacology; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000528:radiation effects; D003094:Collagen; D004307:Dose-Response Relationship, Radiation; D004338:Drug Combinations; D004789:Enzyme Activation / Q000187:drug effects / Q000528:radiation effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000528:radiation effects*; D006801:Humans; D007797:Laminin; D053511:Matrix Metalloproteinase 14 / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000235:genetics* / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D009361:Neoplasm Invasiveness; D010662:Phenylmercuric Acetate / Q000031:analogs & derivatives / Q000494:pharmacology; D011509:Proteoglycans; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019714:Tissue Inhibitor of Metalloproteinases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000906:Antibodies; D004338:Drug Combinations; D004791:Enzyme Inhibitors; D007797:Laminin; D061965:Matrix Metalloproteinase Inhibitors; D011509:Proteoglycans; D012333:RNA, Messenger; D019714:Tissue Inhibitor of Metalloproteinases; C059485:matrigel; C010024:4-aminophenylmercuriacetate; D003094:Collagen; D020778:Matrix Metalloproteinase 2; D053511:Matrix Metalloproteinase 14; D010662:Phenylmercuric Acetate