title: The antipsychotic agent chlorpromazine induces autophagic cell death by inhibiting the Akt/mTOR pathway in human U-87MG glioma cells.
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.
authors.affiliation: Department of Biological Sciences, College of Biological Science and Biotechnology, Research Center for Transcription Control, Konkuk University, Seoul 143-701, Republic of Korea.
authors.forename: Soon Young
authors.initials: SY
authors.lastname: Shin
authors.forename: Kyoung Sun
authors.initials: KS
authors.lastname: Lee
authors.forename: Yang-Kyu
authors.initials: YK
authors.lastname: Choi
authors.forename: Hyunjung Jade
authors.initials: HJ
authors.lastname: Lim
authors.forename: Hong Ghi
authors.initials: HG
authors.lastname: Lee
authors.forename: Yoongho
authors.initials: Y
authors.lastname: Lim
authors.forename: Young Han
authors.initials: YH
authors.lastname: Lee
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects*; D000071186:Beclin-1; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002746:Chlorpromazine / Q000008:administration & dosage*; D015972:Gene Expression Regulation, Neoplastic; D005910:Glioma / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics* / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; D002746:Chlorpromazine; D008565:Membrane Proteins; D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; C491997:BECN1 protein, human; C546842:MTOR protein, human; C494929:PTEN protein, human