title: Discovery and mechanistic study of a small molecule inhibitor for motor protein KIFC1.
abstract: Centrosome amplification is observed in many human cancers and has been proposed to be a driver of both genetic instability and tumorigenesis. Cancer cells have evolved mechanisms to bundle multiple centrosomes into two spindle poles to avoid multipolar mitosis that can lead to chromosomal segregation defects and eventually cell death. KIFC1, a kinesin-14 family protein, plays an essential role in centrosomal bundling in cancer cells, but its function is not required for normal diploid cell division, suggesting that KIFC1 is an attractive therapeutic target for human cancers. To this end, we have identified the first reported small molecule inhibitor AZ82 for KIFC1. AZ82 bound specifically to the KIFC1/microtubule (MT) binary complex and inhibited the MT-stimulated KIFC1 enzymatic activity in an ATP-competitive and MT-noncompetitive manner with a Ki of 0.043 μM. AZ82 effectively engaged with the minus end-directed KIFC1 motor inside cells to reverse the monopolar spindle phenotype induced by the inhibition of the plus end-directed kinesin Eg5. Treatment with AZ82 caused centrosome declustering in BT-549 breast cancer cells with amplified centrosomes. Consistent with genetic studies, our data confirmed that KIFC1 inhibition by a small molecule holds promise for targeting cancer cells with amplified centrosomes and provided evidence that functional suppression of KIFC1 by inhibiting its enzymatic activity could be an effective means for developing cancer therapeutics.
authors.affiliation: Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States.
authors.forename: Jiaquan
authors.initials: J
authors.lastname: Wu
authors.forename: Keith
authors.initials: K
authors.lastname: Mikule
authors.forename: Wenxian
authors.initials: W
authors.lastname: Wang
authors.forename: Nancy
authors.initials: N
authors.lastname: Su
authors.forename: Philip
authors.initials: P
authors.lastname: Petteruti
authors.forename: Farzin
authors.initials: F
authors.lastname: Gharahdaghi
authors.forename: Erin
authors.initials: E
authors.lastname: Code
authors.forename: Xiahui
authors.initials: X
authors.lastname: Zhu
authors.forename: Kelly
authors.initials: K
authors.lastname: Jacques
authors.forename: Zhongwu
authors.initials: Z
authors.lastname: Lai
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Lamb
authors.forename: Claudio
authors.initials: C
authors.lastname: Chuaqui
authors.forename: Nicholas
authors.initials: N
authors.lastname: Keen
authors.forename: Huawei
authors.initials: H
authors.lastname: Chen
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D055808:Drug Discovery; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D016547:Kinesins / Q000037:antagonists & inhibitors*; D008958:Models, Molecular; D011725:Pyridines / Q000737:chemistry* / Q000494:pharmacology*; D054852:Small Molecule Libraries / Q000494:pharmacology*
chemical_list: C000595393:5-methyl-N-(1-oxo-1-(pyrrolidin-3-ylamino)-3-(6-(3-(trifluoromethoxy)phenyl)pyridin-3-yl)propan-2-yl)-4-propylthiophene-2-carboxamide; D004791:Enzyme Inhibitors; C486566:KIFC1 protein, human; D011725:Pyridines; D054852:Small Molecule Libraries; D016547:Kinesins; D000409:Alanine