Open AccessInduction of MiR-21 by Stereotactic Body Radiotherapy Contributes to the Pulmonary Fibrotic Response
Author(s) -
Ohseong Kwon,
Keun Tae Kim,
Eunioo Lee,
Myoungjae Kim,
Seo Hyun Choi,
HengHong Li,
Albert J. Fornace,
Jaeho Cho,
Yun Sil Lee,
Ji Seon Lee,
Yoon Jin Lee,
HyukJin Cha
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0154942
Subject(s) - medicine , cancer research , lung , fibrosis , pulmonary fibrosis , radiation therapy , downregulation and upregulation , lung cancer , pathology , mesenchymal stem cell , epithelial–mesenchymal transition , microrna , cancer , biology , metastasis , biochemistry , gene
Radiation-induced lung fibrosis, the most serious effect of lung cancer radiotherapy on normal tissue, remains a major technical obstacle to the broader application of radiotherapy to patients with lung cancer. This study describes the use of an image-guided irradiation system in mice mimicking stereotactic body radiotherapy (SBRT) to examine the molecular features of chronic fibrotic response after radiation injury. MicroRNA (miR) array analysis of injured pulmonary tissue identified a set of miRs whose expression was significantly increased in damaged lung tissue. In particular, miR-21 expression was increased at the radiation injury site, concurrent with collagen deposition. Although the inhibition of miR-21 by its specific inhibitor anti-miR-21 only marginally affected endothelial-mesenchymal transition (EndMT) in lung endothelial cells, this inhibition significantly reduced collagen synthesis in lung fibroblasts. Furthermore, ectopic expression of miR-21 was sufficient to promote a fibrotic response in lung fibroblasts, enhancing Smad2 phosphorylation concurrent with Smad7 downregulation. These findings indicate that the induction of miR-21 expression is responsible for fibrotic responses observed in mesenchymal cells at the injury site through the potentiation of TGF-β signaling. Local targeting of miR-21 at the injured area could have potential therapeutic utility in mitigating radiation-induced lung fibrosis.