Genetic landscape and ligand-dependent activation of sonic hedgehog-Gli1 signaling in chordomas: a novel therapeutic target

Oncogene. 2020 Jun;39(24):4711-4727. doi: 10.1038/s41388-020-1324-2. Epub 2020 May 14.

Abstract

Chordoma, a rare neoplasm derived from intraosseous notochordal remnants, is unresponsive to conventional chemotherapy and radiotherapy. Sonic Hedgehog (Shh) is a crucial fetal notochord-secreted morphogen that directs notochordal development. The aim of this study was to determine the functional roles and therapeutic potential of Shh-Gli1 signaling in chordomas. Tissue samples and clinical profiles were collected from 42 patients with chordoma. The chordoma cell lines U-CH1 and MUG-Chor1 were used for functional experiments. Shh-Gli1 signaling pathway genetic alterations were screened, and the functions of the identified novel variants were analyzed using in silico analyses, real-time quantitative PCR, and minigene assays. Ligand-dependent Shh-Gli1 signaling activation was assessed using single- and dual-label immunostaining, western blot analysis, and a Shh-responsive Gli-luciferase reporter assay. The small-molecule inhibitor vismodegib was used to target Shh-Gli1 signaling in vitro and in vivo. Overall, 44 genetic alterations were identified, including four novel variants (c.67_69dupCTG in SMO, c.-6_-4dupGGC and c.3306 + 83_3306 + 84insG in PTCH1, and c.183-67_183-66delinsA in SUFU). Shh, PTCH1, SMO, SUFU, and Gli1 were extensively expressed in chordomas, and higher Gli1 expression correlated with poorer prognosis. A luciferase reporter assay and dual-label immunostaining indicated the occurrence of juxtacrine ligand-dependent Shh-Gli1 signaling activation. Vismodegib significantly inhibited cell proliferation and induced apoptosis and G1/S cell cycle arrest. In vivo investigation demonstrated that vismodegib effectively inhibited chordoma xenograft growth. This current preclinical evidence elucidates the therapeutic potential of Shh-Gli1 signaling pathway targeting for chordoma treatment. Vismodegib may be a promising targeted agent, and further clinical trials are warranted.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anilides / pharmacology*
  • Animals
  • Cell Line, Tumor
  • Chordoma* / drug therapy
  • Chordoma* / genetics
  • Chordoma* / metabolism
  • Chordoma* / pathology
  • Drug Delivery Systems*
  • Female
  • G1 Phase Cell Cycle Checkpoints / drug effects
  • G1 Phase Cell Cycle Checkpoints / genetics
  • Gene Expression Regulation, Neoplastic*
  • Hedgehog Proteins* / genetics
  • Hedgehog Proteins* / metabolism
  • Humans
  • Male
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Mutation
  • NIH 3T3 Cells
  • Pyridines / pharmacology*
  • S Phase Cell Cycle Checkpoints / drug effects
  • S Phase Cell Cycle Checkpoints / genetics
  • Signal Transduction* / drug effects
  • Signal Transduction* / genetics
  • Xenograft Model Antitumor Assays
  • Zinc Finger Protein GLI1* / genetics
  • Zinc Finger Protein GLI1* / metabolism

Substances

  • Anilides
  • GLI1 protein, human
  • Hedgehog Proteins
  • HhAntag691
  • Pyridines
  • SHH protein, human
  • Zinc Finger Protein GLI1