Appearance:Solid powderPurity: > 98%
RO3280 is a potent, highly selective inhibitor of Polo-like kinase 1 (PLK1) with IC50 of 3 nM.
IC50 Value: 3 nM (PLK1) 
in vitro: Difluoro-analog 7 (RO3280) gave the best results in both enzymatic (PLK1, IC50 = 3 nM) and cellular (lung cancer cell line H82, EC50 = 6 nM) assays. RO3280 was evaluated for its in vivo antitumor activity in a series of mouse xenograft models, of which the HT-29 colorectal cancer cell line is representative.
in vivo: RO3280 displayed robust antitumor activity ranging from 72% tumor growth inhibition when dosed once weekly at 40 mg/Kg, to complete tumor regression when dosed more frequently.
1:Int J Mol Sci. 2015 Jan 7;16(1):1266-92. doi: 10.3390/ijms16011266. Molecular targeting of the oncoprotein PLK1 in pediatric acute myeloid leukemia: RO3280, a novel PLK1 inhibitor, induces apoptosis in leukemia cells.Wang NN,Li ZH,Zhao H,Tao YF,Xu LX,Lu J,Cao L,Du XJ,Sun LC,Zhao WL,Xiao PF,Fang F,Su GH,Li YH,Li G,Li YP,Xu YY,Zhou HT,Wu Y,Jin MF,Liu L,Ni J,Wang J,Hu SY,Zhu XM,Feng X,Pan J, PMID: 25574601 PMCID: PMC4307303 DOI: 10.3390/ijms16011266 Abstract: Polo-like kinase 1 (PLK1) is highly expressed in many cancers and therefore a biomarker of transformation and potential target for the development of cancer-specific small molecule drugs. RO3280 was recently identified as a novel PLK1 inhibitor; however its therapeutic effects in leukemia treatment are still unknown. We found that the PLK1 protein was highly expressed in leukemia cell lines as well as 73.3% (11/15) of pediatric acute myeloid leukemia (AML) samples. PLK1 mRNA expression was significantly higher in AML samples compared with control samples (82.95 ± 110.28 vs. 6.36 ± 6.35; p < 0.001). Kaplan-Meier survival analysis revealed that shorter survival time correlated with high tumor PLK1 expression (p = 0.002). The 50% inhibitory concentration (IC50) of RO3280 for acute leukemia cells was between 74 and 797 nM. The IC50 of RO3280 in primary acute lymphocytic leukemia (ALL) and AML cells was between 35.49 and 110.76 nM and 52.80 and 147.50 nM, respectively. RO3280 induced apoptosis and cell cycle disorder in leukemia cells. RO3280 treatment regulated several apoptosis-associated genes. The regulation of DCC, CDKN1A, BTK, and SOCS2 was verified by western blot. These results provide insights into the potential use of RO3280 for AML therapy; however, the underlying mechanisms remain to be determined.