Growth-Inhibitory Activity of Bone Morphogenetic Protein 4 in Human Glioblastoma Cell Lines Is Heterogeneous and Dependent on Reduced SOX2 Expression

Mol Cancer Res. 2020 Jul;18(7):981-991. doi: 10.1158/1541-7786.MCR-19-0638. Epub 2020 Mar 31.

Abstract

Glioblastoma multiforme continues to have a dismal prognosis. Even though detailed information on the genetic aberrations in cell signaling and cell-cycle checkpoint control is available, no effective targeted treatment has been developed. Despite the advanced molecular defects, glioblastoma cells may have remnants of normal growth-inhibitory pathways, such as the bone morphogenetic protein (BMP) signaling pathway. We have evaluated the growth-inhibitory effect of BMP4 across a broad spectrum of patient samples, using a panel of 40 human glioblastoma initiating cell (GIC) cultures. A wide range of responsiveness was observed. BMP4 sensitivity was positively correlated with a proneural mRNA expression profile, high SOX2 activity, and BMP4-dependent upregulation of genes associated with inhibition of the MAPK pathway, as demonstrated by gene set enrichment analysis. BMP4 response in sensitive cells was mediated by the canonical BMP receptor pathway involving SMAD1/5/9 phosphorylation and SMAD4 expression. SOX2 was consistently downregulated in BMP4-treated cells. Forced expression of SOX2 attenuated the BMP4 sensitivity including a reduced upregulation of MAPK-inhibitory genes, implying a functional relationship between SOX2 downregulation and sensitivity. The results show an extensive heterogeneity in BMP4 responsiveness among GICs and identify a BMP4-sensitive subgroup, in which SOX2 is a mediator of the response. IMPLICATIONS: Development of agonists targeting the BMP signaling pathway in glioblastoma is an attractive avenue toward a better treatment. Our study may help find biomarkers that predict the outcome of such treatment and enable stratification of patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bone Morphogenetic Protein 4 / metabolism*
  • Bone Morphogenetic Protein 4 / pharmacology
  • Brain Neoplasms / genetics
  • Brain Neoplasms / metabolism*
  • Cell Line, Tumor
  • Gene Expression Regulation, Neoplastic / drug effects
  • Glioblastoma / genetics
  • Glioblastoma / metabolism*
  • Humans
  • MAP Kinase Signaling System / drug effects
  • SOXB1 Transcription Factors / genetics
  • SOXB1 Transcription Factors / metabolism*
  • Up-Regulation / drug effects

Substances

  • BMP4 protein, human
  • Bone Morphogenetic Protein 4
  • SOX2 protein, human
  • SOXB1 Transcription Factors