AZ3146 is a potent and selective Monopolar Spindle 1 (Mps1) kinase inhibitor with IC50 value of 35 nM. AZ3146 acts by interfering with chromosome alignment and overriding the spindle assembly checkpoint.

MPS1 protein kinases play important roles in different steps in mitosis including chromosome attachment and functions at the centrosomes. Additionally, they are also involved in regulation of development and in multiple signaling pathways after mitosis.

In cellular culture, if Mps1 is inhibited by AZ3146 before mitotic entry, this inhibition abloshed the subsequent recruitment of Mad1 and Mad2 to kinetochores. However, if cells were treated with AZ3146 after mitotic entry, the Mad1-C-Mad2 core complex remains kinetochore bound, but O-Mad2 is not recruited to the core. , AZ3146 interferes with chromosome alignment and overrides spindle assembly checkpoint1.

Regarding the effect of AZ3146 administration in vivo, the evidence should be provided by performing the study in human or mice or other animal models.

Reference:
1.   Hewitt L, Tighe A, Santaguida S, et al. Sustained Mps1 activity is required in mitosis to recruit O-Mad2 to the Mad1-C-Mad2 core complex. The Journal of cell biology.2010;190(1):25-34.