Mitotic progression

To evaluate cell cycle stage and microtubule organization, 24 × 10³ OVCAR-3 cells/well were seeded in chamber slides and incubated for 24 h. Cells were treated with anetumab ravtansine for 24 h, fixed in 4% paraformaldehyde for 20 min at 4° C and washed twice with cold PBS. Cells were stained with the PathScan Apoptosis and Proliferation Multiplex IF kit (Cell Signaling Technology) following the manufacturer’s instructions. The primary antibody was incubated overnight at 4° C. Stained cells were mounted using Fluorescent Mounting Medium (Dako) and imaged with an Axio Scan-Z1 (Zeiss) fluorescence microscope.