Figure 3. 41J causes variable cyclin B1 expression, mitotic arrest, and accelerates mitotic entry. (A and B) T98G cells were treated with DMSO, 500 nM or 2 μM 41J for 12 h. Immunofluorescence staining was conducted for cyclin B1 and phospho-histone H3 Ser-10 (P-H3). Cyclin B1 expression was quantified for DMSO-treated cells in all stages of mitosis and 41J-treated cells arrested in prometaphase using ImageJ software. Cells positive (arrowhead) and negative for cyclin B1 (arrow) are indicated for DMSO and 2 μM 41J treatment. (C and D) T98G cells were treated with DMSO or 500 nM 41J for 35 h and observed by time-lapse microscopy. Duration of mitosis (C) and time of mitotic entry (D) were recorded for cells treated with DMSO (n = 75) or 41J (n = 76).