Background:

MLN0905 is a potent inhibitor of PLK1 with IC50 value ranges from 3 to 24 nM [1].

Polo-like kinase 1 (PLK1) is a family of conserved serine/threonine kinases and plays an important role in regulating cell cycle. It has been revealed that PLK1 drives cell cycle progression by triggerting G2/M transition and is considered as a pro-oncogene which overexpressed in tumor cells [2].

MLN0905 is a selective PLK1 inhibitor and has similar effect as RNAi hnockdown. When tested with HT-29 cells, MLN0905 treatment significantly increased pHisH3 expression which indicated that cells were arrested in G2/M phase by inhibiting PLK1 expression [1].

In mouse model with human diffuse large B-cell lymphoma (DLBCL) cell line OCILY-19 subcutaneous xenograft, co-administration of MLN0905 and rituximab markedly reduced tumor volume and increased survival time through inhibiting PLK1 which resulted in mitotic arrest [1]. And the same result was achieved when using nude mice model with human colon tumor HT29 xenograft, MLN0905 treatment significantly inhibited tumor growth or progression [3].

参考文献:
[1].  Shi, J.Q., et al., MLN0905, a small-molecule plk1 inhibitor, induces antitumor responses in human models of diffuse large B-cell lymphoma. Mol Cancer Ther, 2012. 11(9): p. 2045-53.
[2].  Espeut, J., et al., Natural Loss of Mps1 Kinase in Nematodes Uncovers a Role for Polo-like Kinase 1 in Spindle Checkpoint Initiation. Cell Rep, 2015.
[3].   Duffey, M.O., et al., Discovery of a potent and orally bioavailable benzolactam-derived inhibitor of Polo-like kinase 1 (MLN0905). J Med Chem, 2012. 55(1): p. 197-208.