miR-130b directly targets ARHGAP1 to drive activation of a metastatic CDC42-PAK1-AP1 positive feedback loop in Ewing sarcoma

Int J Cancer. 2017 Nov 15;141(10):2062-2075. doi: 10.1002/ijc.30909. Epub 2017 Aug 8.


Ewing Sarcoma (ES) is a highly aggressive bone tumor with peak incidence in the adolescent population. It has a high propensity to metastasize, which is associated with dismal survival rates of approximately 25%. To further understand mechanisms of metastasis we investigated microRNA regulatory networks in ES. Our studies focused on miR-130b due to our analysis that enhanced expression of this microRNA has clinical relevance in multiple sarcomas, including ES. Our studies provide insights into a novel positive feedback network involving the direct regulation of miR-130b and activation of downstream signaling events contributing toward sarcoma metastasis. Specifically, we demonstrated miR-130b induces proliferation, invasion, and migration in vitro and increased metastatic potential in vivo. Using microarray analysis of ES cells with differential miR-130b expression we identified alterations in downstream signaling cascades including activation of the CDC42 pathway. We identified ARHGAP1, which is a negative regulator of CDC42, as a novel, direct target of miR-130b. In turn, downstream activation of PAK1 activated the JNK and AP-1 cascades and downstream transcriptional targets including IL-8, MMP1 and CCND1. Furthermore, chromatin immunoprecipitation of endogenous AP-1 in ES cells demonstrated direct binding to an upstream consensus binding site within the miR-130b promoter. Finally, small molecule inhibition of PAK1 blocked miR-130b activation of JNK and downstream AP-1 target genes, including primary miR-130b transcripts, and miR-130b oncogenic properties, thus identifying PAK1 as a novel therapeutic target for ES. Taken together, our findings identify and characterize a novel, targetable miR-130b regulatory network that promotes ES metastasis.

Keywords: CDC42; Ewing sarcoma; PAK1; metastasis; microRNA.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Apoptosis
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Bone Neoplasms / genetics
  • Bone Neoplasms / metabolism
  • Bone Neoplasms / pathology*
  • Cell Movement
  • Cell Proliferation
  • Epithelial-Mesenchymal Transition
  • Feedback, Physiological
  • GTPase-Activating Proteins / genetics
  • GTPase-Activating Proteins / metabolism*
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Liver Neoplasms / genetics
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / secondary*
  • Lung Neoplasms / genetics
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / secondary*
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • MicroRNAs / genetics*
  • Neoplasm Staging
  • Prognosis
  • Sarcoma, Ewing / genetics
  • Sarcoma, Ewing / metabolism
  • Sarcoma, Ewing / pathology*
  • Signal Transduction
  • Transcription Factor AP-1 / genetics
  • Transcription Factor AP-1 / metabolism
  • Tumor Cells, Cultured
  • Xenograft Model Antitumor Assays
  • cdc42 GTP-Binding Protein / genetics
  • cdc42 GTP-Binding Protein / metabolism
  • p21-Activated Kinases / genetics
  • p21-Activated Kinases / metabolism


  • ARHGAP1 protein, human
  • Biomarkers, Tumor
  • GTPase-Activating Proteins
  • MIRN130 microRNA, human
  • MicroRNAs
  • Transcription Factor AP-1
  • PAK1 protein, human
  • p21-Activated Kinases
  • cdc42 GTP-Binding Protein