title: Molecular basis underlying resistance to Mps1/TTK inhibitors.
abstract: Mps1/TTK is a dual-specificity kinase, with an essential role in mitotic checkpoint signaling, which has emerged as a potential target in cancer therapy. Several Mps1/TTK small-molecule inhibitors have been described that exhibit promising activity in cell culture and xenograft models. Here, we investigated whether cancer cells can develop resistance to these drugs. To this end, we treated various cancer cell lines with sublethal concentrations of a potent Mps1/TTK inhibitor in order to isolate inhibitor-resistant monoclonal cell lines. We identified four point mutations in the catalytic domain of Mps1/TTK that gave rise to inhibitor resistance but retained wild-type catalytic activity. Interestingly, cross-resistance of the identified mutations to other Mps1/TTK inhibitors is limited. Our studies predict that Mps1/TTK inhibitor-resistant tumor cells can arise through the acquisition of mutations in the adenosine triphosphate-binding pocket of the kinase that prevent stable binding of the inhibitors. In addition, our results suggest that combinations of inhibitors could be used to prevent acquisition of drug resistance. Interestingly, cross-resistance seems nonspecific for inhibitor scaffolds, a notion that can be exploited in future drug design to evict possible resistance mutations during clinical treatment.
authors.affiliation: Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Koch
authors.affiliation: Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Maia
authors.affiliation: Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Janssen
authors.affiliation: Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: R H
authors.initials: RH
authors.lastname: Medema
mesh_terms: D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics*; D045744:Cell Line, Tumor; D015195:Drug Design; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D006801:Humans; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics*
chemical_list: D018797:Cell Cycle Proteins; D047428:Protein Kinase Inhibitors; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; C075840:TTK protein, human