Global gene expression profiles reveal an increase in mRNA levels of collagens, MMPs, and TIMPs in late radiation enteritis.
Radiation enteritis, a common complication of radiation therapy for abdominal and pelvic cancers, is characterized by severe transmural fibrosis associated with mesenchymal cell activation, tissue disorganization, and deposition of fibrillar collagen. To investigate the mechanisms involved in this pathological accumulation of extracellular matrix, we studied gene expression of matrix components along with that of genes involved in matrix remodeling, matrix metalloproteinases (MMPs), and tissue inhibitors of metalloproteinases (TIMPs). Hybrid selection on high-density cDNA array, real-time RT-PCR, gelatin zymography and immunohistochemistry were used to characterize the mRNA expression profile, activity, and tissue location of extracellular matrix-related genes in radiation enteritis compared with healthy ileum. cDNA array analysis revealed a strong induction of genes coding for collagens I, III, IV, VI, and VIII, SPARC, and tenascin-C, extracellular-matrix degrading enzymes (MMP-1, -2, -3, -14, -18+19), and metalloproteinase inhibitors (TIMP-1, -2, plasminogen activator inhibitor-1) in radiation enteritis. This increase was correlated with the degree of infiltration of the mucosa by inflammatory cells, and the presence of differentiated mesenchymal cells in the submucosa and muscularis propria. Despite the fact that expression of collagens, MMPs, and TIMPs simultaneously increase, quantification of net collagen deposition shows an overall accumulation of collagen. Our results indicate that late radiation enteritis tissues are subjected to active process of fibrogenesis as well as fibrolysis, with a balance toward fibrogenesis. This demonstrates that established fibrotic tissue is not scarred fixed tissue but is subjected to a dynamic remodeling process.
Strup-Perrot
Carine
C
Laboratoire UPRES EA 27-10 Radiosensibilité des tumeurs et tissus sains, Institut Gustave Roussy/Institut de Radioprotection et de Sûreté Nucléaire, 94805 Villejuif, France.
Mathé
Denis
D
Linard
Christine
C
Violot
Dominique
D
Milliat
Fabien
F
François
Agnès
A
Bourhis
Jean
J
Vozenin-Brotons
Marie-Catherine
MC
D001706:Biopsy; D003094:Collagen / Q000235:genetics*; D004751:Enteritis / Q000209:etiology / Q000235:genetics* / Q000503:physiopathology; D005355:Fibrosis; D018093:Gelatinases / Q000235:genetics; D020869:Gene Expression Profiling; D006801:Humans; D007422:Intestines / Q000473:pathology / Q000503:physiopathology / Q000528:radiation effects; D019278:Matrix Metalloproteinase 3 / Q000235:genetics; D020782:Matrix Metalloproteinases / Q000235:genetics*; D009369:Neoplasms / Q000532:radiotherapy; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000378:metabolism; D011832:Radiation Injuries / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019714:Tissue Inhibitor of Metalloproteinases / Q000235:genetics*
D012333:RNA, Messenger; D019714:Tissue Inhibitor of Metalloproteinases; D003094:Collagen; D018093:Gelatinases; D020782:Matrix Metalloproteinases; D019278:Matrix Metalloproteinase 3