Ro3280 (RO3280) inhibits PLK1 activity in NB4 and K562 cells, with an IC50s of 13.45 nM and 301 nM, respectively. RO3280 shows inhibitory activities against the growth of six leukemia cells, with IC50s of 186 nM, 175 nM, 74 nM, 797 nM, 120 nM and 162 nM for U937, HL60, NB4, K562, MV4-11 and CCRF cell lines, respectively. RO3280 also suppresses the growth of primary ALL and AML cells, with IC50s of 35.49-110.76 nM, and 52.80-147.50 nM, respectively. RO3280 (50 or 100 nM) induces apoptosis and cell cycle disorder in acute leukemia cells. Ro3280 shows potent activity in H82, H69, A549 lung cancer cell lines with EC50s of 6 nM, 7 nM and 82 nM. Ro3280 also inhibits several other cancer cell lines, with low concentration. RO3280 is cytotoxic to 5637 and T24 human bladder cancer cells, with IC50s of appr 100 nM.