G2 cell cycle arrest, down-regulation of cyclin B, and induction of mitotic catastrophe by the flavoprotein inhibitor diphenyleneiodonium.
Because proliferation of eukaryotic cells requires cell cycle-regulated chromatid separation by the mitotic spindle, it is subject to regulation by mitotic checkpoints. To determine the mechanism of the antiproliferative activity of the flavoprotein-specific inhibitor diphenyleneiodonium (DPI), I have examined its effect on the cell cycle and mitosis. Similar to paclitaxel, exposure to DPI causes an accumulation of cells with a 4N DNA content. However, unlike the paclitaxel-mediated mitotic block, DPI-treated cells are arrested in the cell cycle prior to mitosis. Although DPI-treated cells can arrest with fully separated centrosomes at opposite sides of the nucleus, these centrosomes fail to assemble mitotic spindle microtubules and they do not accumulate the Thr(288) phosphorylated Aurora-A kinase marker of centrosome maturation. In contrast with paclitaxel-arrested cells, DPI impairs cyclin B1 accumulation. Release from DPI permits an accumulation of cyclin B1 and progression of the cells into mitosis. Conversely, exposure of paclitaxel-arrested mitotic cells to DPI causes a precipitous drop in cyclin B and Thr(288) phosphorylated Aurora-A levels and leads to mitotic catastrophe in a range of cancerous and noncancerous cells. Hence, the antiproliferative activity of DPI reflects a novel inhibitory mechanism of cell cycle progression that can reverse spindle checkpoint-mediated cell cycle arrest.
Laboratory for Cancer Medicine, West Australian Institute for Medical Research, Perth, Western Australia 6009, Australia. rscaife@cyllene.uwa.edu.au
Robin M
RM
Scaife
D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology; D017209:Apoptosis; D064096:Aurora Kinase A; D064127:Aurora Kinases; D015153:Blotting, Western; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D018385:Centrosome / Q000378:metabolism / Q000648:ultrastructure; D002842:Chromatids / Q000378:metabolism; D019926:Cyclin B / Q000096:biosynthesis* / Q000378:metabolism; D056744:Cyclin B1; D004247:DNA / Q000378:metabolism; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005420:Flavoproteins / Q000037:antagonists & inhibitors*; D005434:Flow Cytometry; D016195:G2 Phase; D006801:Humans; D020935:MAP Kinase Signaling System; D051379:Mice; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast; D008938:Mitosis; D041681:NIH 3T3 Cells; D009861:Onium Compounds / Q000494:pharmacology*; D017239:Paclitaxel / Q000494:pharmacology; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism; D013912:Threonine / Q000737:chemistry; D013997:Time Factors; D029867:Xenopus Proteins
D000975:Antioxidants; C534699:CCNB1 protein, human; C534700:Ccnb1 protein, mouse; C534701:Ccnb1 protein, rat; D018797:Cell Cycle Proteins; D019926:Cyclin B; D056744:Cyclin B1; D004791:Enzyme Inhibitors; D005420:Flavoproteins; D009861:Onium Compounds; D017382:Reactive Oxygen Species; D029867:Xenopus Proteins; D013912:Threonine; C007517:diphenyleneiodonium; D004247:DNA; D011494:Protein Kinases; C112134:AURKA protein, Xenopus; C576918:Aurka protein, mouse; C576920:Aurka protein, rat; D064096:Aurora Kinase A; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D017239:Paclitaxel