Valproate sensitizes human glioblastoma cells to 3-bromopyruvate-induced cytotoxicity

Int J Pharm. 2018 Nov 15;551(1-2):97-102. doi: 10.1016/j.ijpharm.2018.08.039. Epub 2018 Aug 20.


Glioblastoma (GBM) is the most common brain tumor; however, no effective treatment for it is available yet. Monocarboxylate transporters, which are highly expressed in GBM, play a role in transporting antitumor agents, such as 3-bromopyruvate (3-BrPA). Valproate, primarily used to treat epilepsy, has been considered a possible treatment option for malignant GBM. In this study, we aimed to investigate the combined effects of 3-BrPA and valproate on GBM cell growth and elucidate the underlying mechanisms. Valproate enhanced 3-BrPA-induced cell death in T98G cells, used as a GBM model. Multidrug resistance-associated protein 2 (MRP2) and breast cancer resistance protein (BCRP) mRNA levels significantly increased after valproate treatment. 3-BrPA-induced cell death, which was enhanced by valproate, was inhibited in the presence of MK571, a MRP inhibitor, or Ko143, a BCRP inhibitor. In addition, treatment with 3-BrPA and valproate for 48 h reduced cellular ATP levels compared to those in the 3-BrPA alone treatment group. However, cellular ATP levels were recovered in the presence of MK571 or Ko143, compared to those in the 3-BrPA and valproate treatment groups. In conclusion, we suggested that valproate enhanced 3-BrPA-induced cell death. This might be attributable to the increase in cellular ATP consumption owing to valproate-induced MRP2 or BCRP expression.

Keywords: 3-Bromopyruvate; ATP-binding cassette transporter; Glioblastoma; Monocarboxylate transporter; Valproate.

MeSH terms

  • ATP-Binding Cassette Transporters / genetics
  • Adenosine Triphosphate / metabolism
  • Antineoplastic Agents / administration & dosage*
  • Brain Neoplasms / drug therapy*
  • Brain Neoplasms / metabolism
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Glioblastoma / drug therapy*
  • Glioblastoma / metabolism
  • Humans
  • Pyruvates / administration & dosage*
  • RNA, Messenger / metabolism
  • Valproic Acid / administration & dosage*


  • ATP-Binding Cassette Transporters
  • Antineoplastic Agents
  • Pyruvates
  • RNA, Messenger
  • Valproic Acid
  • bromopyruvate
  • Adenosine Triphosphate