Taxol induces oxidative neuronal cell death by enhancing the activity of NADPH oxidase in mouse cortical cultures.
We examined the involvement of oxidative stress in neuronal cell death induced by taxol, a microtubule-stabilizing anti-cancer drug and investigated whether NADPH oxidase plays a role in taxol-induced neuronal cell death in mouse cortical cultures. Cell death was assessed by measuring lactate dehydrogenase in the bathing media after 24-h exposure to taxol. Taxol (30-1000 nM) induced the concentration-dependent neuronal death with apoptotic features. The neuronal death induced by taxol was significantly attenuated not only by anti-apoptotic drugs such as z-VAD-fmk and cycloheximide but also by antioxidants such as trolox, ascorbic acid and tempol. Vinblastine, a microtubule-depolymerizing anti-cancer drug, also induced neuronal death. The neuronal cell death induced by vinblastine was also attenuated by z-VAD-fmk, but not by antioxidants and NADPH oxidase inhibitors. Exposure the cortical cultures to taxol for 80 min formed neurite beadings visualized by fluorescence immunocytochemistry for tubulin. Treatment with either trolox or apocynin, an NADPH oxidase inhibitor, did not affect formation of the neurite beadings. RT-PCR and Western blot analysis revealed that exposure to taxol increased the expression of p47(phox) and gp91(phox) and induced translocation of the p47(phox) to the membrane in cortical cultures. Exposure to taxol markedly increased cellular 2,7-dichlorofluorescin diacetate fluorescence, an indicator for reactive oxygen species. Apocynin and trolox markedly inhibited the taxol-induced increase of the fluorescence. Moreover, treatment with NADPH oxidase inhibitors or suppression of gp91(phox) by siRNA significantly attenuated the taxol-induced neuronal death. These results indicate that taxol induces oxidative neuronal apoptosis by enhancing the activity of NADPH oxidase.
Jang
Hong Jeon
HJ
Department of Neurosurgery, Kwangju Christian Hospital, Gwangju 503-715, Republic of Korea.
Hwang
Shinae
S
Cho
Kyu Yong
KY
Kim
Do Kyung
DK
Chay
Kee-Oh
KO
Kim
Jong-Keun
JK
D000074183:ATPases Associated with Diverse Cellular Activities; D000818:Animals; D000831:Animals, Newborn; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology*; D002839:Chromans / Q000494:pharmacology; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D051379:Mice; D008813:Mice, Inbred ICR; D019255:NADPH Oxidases / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000494:pharmacology; D009930:Organic Chemicals; D017239:Paclitaxel / Q000494:pharmacology*; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014747:Vinblastine / Q000494:pharmacology
D000972:Antineoplastic Agents, Phytogenic; D002839:Chromans; D004791:Enzyme Inhibitors; D018696:Neuroprotective Agents; D009930:Organic Chemicals; C105949:Pirb protein, mouse; D011971:Receptors, Immunologic; C402795:SYTOX Green; D014747:Vinblastine; D019255:NADPH Oxidases; D000074183:ATPases Associated with Diverse Cellular Activities; D004265:DNA Helicases; C518330:RUVBL2 protein, mouse; D017239:Paclitaxel; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid