Background:

Mps1-IN-1 is a selective Mps1 (monopolar spindle 1) kinase inhibitor with IC50 value of 367 nM.

MPS1 (monopolar spindle 1 kinase) is a crucial part of the spindle assembly checkpoint. It facilitates the formation of C-MAD2 (closed MAD2) conformer and the MCC (mitotic checkpoint complex) assembly, involved in the maintenance of chromosomal stability and tumor growth.

Mps1-IN-1 abolishes the SAC (spindle assembly checkpoint) function. In U2OS cells, dose-dependent treatment of Mps1-IN-1 decreases the time spent in mitosis with almost 100% cells starting anaphase in 20 minutes. In contrast, just 10% of DMSO-treated cells starting anaphase in the same period. Acceleration of mitosis kinetics in Mps1-IN-1 treated cells affects genomic stability and causes aneuploidy. In addition, Mps1-IN-1 treated cells shows decrease in kinetochore-bound Mad2 by 80%. Mps1-IN-1–treated cells spent roughly 40% less time in mitosis as compared to DMSO-treated cells. Moreover, Mps1-IN-1 disrupts the kinase activity of Aurora B. Mps1-IN-1 treatment lead to decrease in the phosphorylation status of Aurora B at Thr232 in a dose-dependent manner. Furthermore, Mps1-IN-1 increases multipolar cell divisions and decreases cell viability.

Reference:
[1].Kwiatkowski N, Jelluma N, Filippakopoulos P et al.? Small-molecule kinase inhibitors provide insight into Mps1 cell cycle function. Nat Chem Biol. 2010 May;6(5):359-68.