IRX1 hypomethylation promotes osteosarcoma metastasis via induction of CXCL14/NF-κB signaling

J Clin Invest. 2015 May;125(5):1839-56. doi: 10.1172/JCI78437. Epub 2015 Mar 30.

Abstract

Osteosarcoma is a common malignant bone tumor with a propensity to metastasize to the lungs. Epigenetic abnormalities have been demonstrated to underlie osteosarcoma development; however, the epigenetic mechanisms that are involved in metastasis are not yet clear. Here, we analyzed 2 syngeneic primary human osteosarcoma cell lines that exhibit disparate metastatic potential for differences in epigenetic modifications and expression. Using methylated DNA immunoprecipitation (MeDIP) and microarray expression analysis to screen for metastasis-associated genes, we identified Iroquois homeobox 1 (IRX1). In both human osteosarcoma cell lines and clinical osteosarcoma tissues, IRX1 overexpression was strongly associated with hypomethylation of its own promoter. Furthermore, experimental modulation of IRX1 in osteosarcoma cell lines profoundly altered metastatic activity, including migration, invasion, and resistance to anoikis in vitro, and influenced lung metastasis in murine models. These prometastatic effects of IRX1 were mediated by upregulation of CXCL14/NF-κB signaling. In serum from osteosarcoma patients, the presence of IRX1 hypomethylation in circulating tumor DNA reduced lung metastasis-free survival. Together, these results identify IRX1 as a prometastatic gene, implicate IRX1 hypomethylation as a potential molecular marker for lung metastasis, and suggest that epigenetic reversion of IRX1 activation may be beneficial for controlling osteosarcoma metastasis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anoikis
  • Base Sequence
  • Bone Neoplasms / genetics
  • Bone Neoplasms / metabolism
  • Bone Neoplasms / pathology*
  • Cell Line, Tumor
  • Cell Movement
  • Chemokines, CXC / physiology*
  • DNA Methylation*
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic / genetics*
  • High-Throughput Screening Assays
  • Homeodomain Proteins / biosynthesis
  • Homeodomain Proteins / blood
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / physiology*
  • Humans
  • Lung Neoplasms / secondary
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Molecular Sequence Data
  • NF-kappa B / physiology*
  • Neoplasm Invasiveness
  • Neoplasm Proteins / biosynthesis
  • Neoplasm Proteins / blood
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / physiology*
  • Neoplasm Transplantation
  • Osteosarcoma / genetics
  • Osteosarcoma / metabolism
  • Osteosarcoma / secondary*
  • Promoter Regions, Genetic / genetics*
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • RNA, Neoplasm / biosynthesis
  • RNA, Neoplasm / genetics
  • Transcription Factors / biosynthesis
  • Transcription Factors / blood
  • Transcription Factors / genetics
  • Transcription Factors / physiology*
  • Transcription, Genetic

Substances

  • CXCL14 protein, human
  • Chemokines, CXC
  • Homeodomain Proteins
  • IRX1 protein, human
  • NF-kappa B
  • Neoplasm Proteins
  • RNA, Messenger
  • RNA, Neoplasm
  • Transcription Factors

Associated data

  • GEO/GSE55957
  • GEO/GSE55958
  • GEO/GSE55961