Characterization of phenothiazine-induced apoptosis in neuroblastoma and glioma cell lines: clinical relevance and possible application for brain-derived tumors.
In this study we aimed to (1). screen phenothiazines for cytotoxic activity in glioma, neuroblastoma, and primary mouse brain tissue; and (2). determine the mechanism of the cytotoxic effect (apoptosis, necrosis) and the roles of calmodulin inhibition and sigma receptor modulation. Rat glioma (C6) and human neuroblastoma (SHSY-5Y) cell lines were treated with different phenothiazines. All agents induced a dose-dependent decrease in viability and proliferation, with the highest activity elicited by thioridazine. Sensitivity to thioridazine of glioma and neuroblastoma cells was significantly higher (p < 0.05) than that of primary mouse brain culture (IC50 11.2 and 15.1 microM vs 41.3 microM, respectively). The N-mustard fluphenazine induced significantly lower cytotoxicity in glioma cells, compared to fluphenazine. The sigma receptor selective ligand (+)-SK&F10047 increased viability slightly while combined with fluphenazine; SK&F10047 did not alter fluphenazine activity. Flow cytometry of propidium iodide (PI)-stained glioma cells treated with thioridazine, fluphenazine, or perphenazine (6-50 microM) resulted in a concentration-dependent increase of fragmented DNA up to 94% vs 3% in controls by all agents. Thioridazine (12.5 microM)-treated glioma cells costained with PI and Hoechst 33342 revealed a red fluorescence of fragmented nuclei in treated cells and a blue fluorescence of intact control nuclei. After 4-h exposure to thioridazine (25 and 50 microM), a 25- to 30-fold increase in caspase-3 activity in neuroblastoma cells was noted. Overall, the marked apoptotic effect of phenothiazines in brain-derived cancer cells, and the low sensitivity of primary brain tissue suggest the potential use of selected agents as therapeutic modalities in brain cancer.
Gil-Ad
Irit
I
Laboratory of Biological Psychiatry, Felsenstein Medical Research Center, Campus Rabin, Petah-Tiqva 49100, Israel, and Sackler School of Medicine, Tel-Aviv University, Ramat Aviv, Israel. iritgil@post.tau.ac.il
Shtaif
Biana
B
Levkovitz
Yechiel
Y
Dayag
Michal
M
Zeldich
Ella
E
Weizman
Abraham
A
D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001932:Brain Neoplasms / Q000188:drug therapy*; D002147:Calmodulin / Q000187:drug effects / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D053938:DNA Fragmentation / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005476:Fluphenazine / Q000633:toxicity; D005910:Glioma / Q000188:drug therapy*; D006801:Humans; D051379:Mice; D008813:Mice, Inbred ICR; D009447:Neuroblastoma / Q000188:drug therapy*; D010620:Phenazocine / Q000031:analogs & derivatives* / Q000494:pharmacology; D010640:Phenothiazines / Q000627:therapeutic use / Q000633:toxicity*; D051381:Rats; D017480:Receptors, sigma / Q000187:drug effects / Q000378:metabolism; D013881:Thioridazine / Q000633:toxicity; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D000970:Antineoplastic Agents; D002147:Calmodulin; D010640:Phenothiazines; D017480:Receptors, sigma; C012134:SK&F 10047; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; C031637:phenothiazine; D010620:Phenazocine; D013881:Thioridazine; D005476:Fluphenazine