The antipsychotic agent chlorpromazine induces autophagic cell death by inhibiting the Akt/mTOR pathway in human U-87MG glioma cells

Carcinogenesis. 2013 Sep;34(9):2080-9. doi: 10.1093/carcin/bgt169. Epub 2013 May 20.

Abstract

2-Chloro-10-[3(-dimethylamino)propyl]phenothiazine mono hydrochloride (chlorpromazine; CPZ) is an antipsychotic agent that was originally developed to control psychotic disorders. The cytotoxic properties of the CPZ are well known, but its mechanism of action is poorly understood. In this study, we investigated the role of apoptosis and autophagy in CPZ-induced cytotoxicity in U-87MG glioma cells. CPZ treatment inhibited cell proliferation and long-term clonogenic survival. Additionally, CPZ triggered autophagy, as indicated by electron microscopy and accumulation of the membrane form of microtubule-associated protein 1 light chain 3 (LC3-II); however, CPZ did not induce apoptosis. Inhibition of autophagy by expression of Beclin 1 small interfering RNA (siRNA) in U-87MG cells attenuated CPZ-induced LC3-II formation. Furthermore, U-87MG cells expressing Beclin 1 siRNA attenuated CPZ-induced cell death. CPZ inhibited phosphatidylinositol 3-kinase (PI3K)/AKT/ mTOR pathway in U-87MG cells. Treatment with LY294002, a PI3K inhibitor, alone increased the accumulation of LC3-II and potentiated the effect of CPZ. In contrast, exogenous expression of AKT partially inhibited CPZ-induced LC3-II formation. When U-87MG cells were implanted into the brain of athymic nude mouse, CPZ triggered autophagy and inhibited xenograft tumor growth. These results provided the first evidence that CPZ-induced cytotoxicity is mediated through autophagic cell death in PTEN (phosphatase and tensin homolog deleted on chromosome 10)-null U-87MG glioma cells by inhibiting PI3K/AKT/mTOR pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins / metabolism
  • Autophagy / drug effects*
  • Beclin-1
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Chlorpromazine / administration & dosage*
  • Gene Expression Regulation, Neoplastic
  • Glioma / drug therapy*
  • Glioma / pathology
  • Humans
  • Membrane Proteins / metabolism
  • Mice
  • PTEN Phosphohydrolase / metabolism
  • Phosphatidylinositol 3-Kinases / metabolism
  • Proto-Oncogene Proteins c-akt / genetics*
  • Proto-Oncogene Proteins c-akt / metabolism
  • TOR Serine-Threonine Kinases / genetics*
  • TOR Serine-Threonine Kinases / metabolism
  • Xenograft Model Antitumor Assays

Substances

  • Apoptosis Regulatory Proteins
  • BECN1 protein, human
  • Beclin-1
  • Membrane Proteins
  • Phosphatidylinositol 3-Kinases
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • PTEN Phosphohydrolase
  • PTEN protein, human
  • Chlorpromazine