Figure 3.

Volasertib prevents bipolar spindle formation, inducing cell cycle arrest in the early M phase. Immunofluorescence analysis of NCI-H460 NSCLC cells treated for 24 h with either (a) 0.1% dimethyl sulfoxide or (b) 100 nM/l volasertib. Cells were fixed and stained with 4', 6-diamidino-2-phenylindole (to stain DNA; blue), anti-tubulin (to stain spindles; green) and anti-phosphoSer10 histone H3 (pink). Volasertib treatment resulted in an accumulation of mitotic cells with monopolar spindles in which the kinetochores were not properly attached to the spindle—a cellular phenotype termed ‘Polo arrest'. Reprinted from Clinical Cancer Research, Copyright 2009, 15/9, 3094–3102, Rudolph et al.¹⁹ ‘BI 6727, a Polo-like kinase inhibitor with improved pharmacokinetic profile and broad antitumor activity', with permission from AACR.