NBM-BMX, an HDAC8 Inhibitor, Overcomes Temozolomide Resistance in Glioblastoma Multiforme by Downregulating the β-Catenin/c-Myc/SOX2 Pathway and Upregulating p53-Mediated MGMT Inhibition

Int J Mol Sci. 2021 May 31;22(11):5907. doi: 10.3390/ijms22115907.

Abstract

Although histone deacetylase 8 (HDAC8) plays a role in glioblastoma multiforme (GBM), whether its inhibition facilitates the treatment of temozolomide (TMZ)-resistant GBM (GBM-R) remains unclear. By assessing the gene expression profiles from short hairpin RNA of HDAC8 in the new version of Connectivity Map (CLUE) and cells treated by NBM-BMX (BMX)-, an HDAC8 inhibitor, data analysis reveals that the Wnt signaling pathway and apoptosis might be the underlying mechanisms in BMX-elicited treatment. This study evaluated the efficacy of cotreatment with BMX and TMZ in GBM-R cells. We observed that cotreatment with BMX and TMZ could overcome resistance in GBM-R cells and inhibit cell viability, markedly inhibit cell proliferation, and then induce cell cycle arrest and apoptosis. In addition, the expression level of β-catenin was reversed by proteasome inhibitor via the β-catenin/ GSK3β signaling pathway to reduce the expression level of c-Myc and cyclin D1 in GBM-R cells. BMX and TMZ cotreatment also upregulated WT-p53 mediated MGMT inhibition, thereby triggering the activation of caspase-3 and eventually leading to apoptosis in GBM-R cells. Moreover, BMX and TMZ attenuated the expression of CD133, CD44, and SOX2 in GBM-R cells. In conclusion, BMX overcomes TMZ resistance by enhancing TMZ-mediated cytotoxic effect by downregulating the β-catenin/c-Myc/SOX2 signaling pathway and upregulating WT-p53 mediated MGMT inhibition. These findings indicate a promising drug combination for precision personal treating of TMZ-resistant WT-p53 GBM cells.

Keywords: GBM; HDAC8; MGMT; TMZ; connectivity map; p53; β-catenin.

MeSH terms

  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • DNA Modification Methylases / genetics*
  • DNA Repair Enzymes / genetics*
  • Drug Resistance, Neoplasm / genetics
  • Gene Expression Regulation, Neoplastic / drug effects
  • Glioblastoma / drug therapy*
  • Glioblastoma / genetics
  • Glioblastoma / pathology
  • Histone Deacetylases / genetics*
  • Humans
  • Repressor Proteins / antagonists & inhibitors
  • Repressor Proteins / genetics*
  • Small Molecule Libraries / pharmacology
  • Temozolomide / adverse effects
  • Temozolomide / pharmacology
  • Tumor Suppressor Protein p53 / genetics*
  • Tumor Suppressor Proteins / genetics*
  • Xenograft Model Antitumor Assays
  • beta Catenin / genetics*

Substances

  • CTNNB1 protein, human
  • Repressor Proteins
  • Small Molecule Libraries
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Tumor Suppressor Proteins
  • beta Catenin
  • DNA Modification Methylases
  • MGMT protein, human
  • HDAC8 protein, human
  • Histone Deacetylases
  • DNA Repair Enzymes
  • Temozolomide