EM011 induces mitotic arrest by the activation of the spindle checkpoint. A shows immunoblots for BubR1 and MPM-2. Uniform loading of lysates was confirmed by immunoblotting for actin. B. Cells were analyzed for mitotic population at 72 hrs post-treatment using two-color flow cytometry. Representative dot-plot shows a clear 8N mitotic population (MPM-2 positive population) suggesting that mitotically exited cells continue to progress in the cell-cycle and enter a second round of DNA replication and mitosis. C shows an abnormally massive mitotic cell at 72 hrs (left) and a significantly huge G1-like multinucleate cell (right).