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.

Different Modulation of Rps6 Phosphorylation by Risperidone in Striatal Cells Sub Populations: Involvement of the mTOR Pathway in Antipsychotic-Induced Extrapyramidal Symptoms in Mice

“…Recently, various authors have implicated the mTOR signaling pathway in the modulation exerted by AP drugs such as thioridazine [12,13], olanzapine [14], haloperidol [15,16] and risperidone [17], among others. In parallel, several studies provide evidence for the involvement of disrupted mTOR signaling in the neuropathology of schizophrenia [18].…”

Targeting Cancer Cells via the Reactive Oxygen Species-Mediated Unfolded Protein Response with a Novel Synthetic Polyphenol Conjugate

“…Inhibiting autophagy facilitates DPP-23-induced apoptosis Beclin-1, an ortholog of yeast atg6/vps30 (23), is essential for the initiation of autophagy (24), and so silencing Beclin-1 prevents the progression of autophagy (16). In MIA PaCa-2 cells expressing Beclin-1 siRNA (siBECN1), DPP-23-induced PARP cleavage (Fig.…”

“…Xenograft tumor experiments were performed as described previously (15,16). The detailed procedure was described in Supplementary Methods.…”

“…The blots were probed with respective primary antibodies then incubated with secondary antibodies conjugated to horseradish peroxidase as described previously (16). The list of primary antibodies was described in Supplementary Methods.…”

Repurposing antipsychotics as glioblastoma therapeutics: Potentials and challenges

“…The anti-glioma effects of phenothiazines have been reported (63). Tricyclic neuroleptic drugs, such as chlorpromazine, promoted autophagic cell death in the PTEN-null U-87MG glioma cell line by inhibiting the PI3K/AKT/mTOR pathway (64). In addition, antipsychotics, such as paliperidone, pimozide and risperidone, which are selective 5-HT 7 inhibitors, have been studied for their potential use as an adjuvant chemotherapy in the management of GBM (65).…”