Stereospecific targeting of MTH1 by (S)-crizotinib as an anticancer strategy
Résumé
Activated RAS GTPase signalling is a critical driver of oncogenic transformation and malignant disease. Cellular models of RAS-dependent cancers have been used to identify experimental small molecules, such as SCH51344, but their molecular mechanism of action remains generally unknown. Here, using a chemical proteomic approach, we identify the target of SCH51344 as the human mutT homologue MTH1 (also known as NUDT1), a nucleotide pool sanitizing enzyme. Loss-of-function of MTH1 impaired growth of KRAS tumour cells, whereas MTH1 overexpression mitigated sensitivity towards SCH51344. Searching for more drug-like inhibitors, we identified the kinase inhibitor crizotinib as a nanomolar suppressor of MTH1 activity. Surprisingly, the clinically used (R)-enantiomer of the drug was inactive, whereas the (S)-enantiomer selectively inhibited MTH1 catalytic activity. Enzymatic assays, chemical proteomic profiling, kinome-wide activity surveys and MTH1 co-crystal structures of both enantiomers provide a rationale for this remarkable stereospecificity. Disruption of nucleotide pool homeostasis via MTH1 inhibition by (S)-crizotinib induced an increase in DNA single-strand breaks, activated DNA repair in human colon carcinoma cells, and effectively suppressed tumour growth in animal models. Our results propose (S)-crizotinib as an attractive chemical entity for further pre-clinical evaluation, and small-molecule inhibitors of MTH1 in general as a promising novel class of anticancer agents.
Mots clés
Humans
Female
Animals
Models
Molecular
Mice
Disease Models
Animal
DNA Repair
Xenograft Model Antitumor Assays
Proteomics
Protein Conformation
Aminoquinolines/pharmacology
Antineoplastic Agents/chemistry/*pharmacology
Colonic Neoplasms/drug therapy/genetics/pathology
Crystallization
DNA Breaks
Single-Stranded/drug effects
DNA Repair Enzymes/*antagonists & inhibitors/biosynthesis/chemistry/*metabolism
Homeostasis/drug effects
inhibitors/biosynthesis/chemistry/*metabolism
SCID
Nucleotides/metabolism
Phosphoric Monoester Hydrolases/*antagonists &
Protein Kinase Inhibitors/chemistry/*pharmacology
Proto-Oncogene Proteins/genetics
Pyrazoles/chemistry/*pharmacology
Pyridines/chemistry/*pharmacology
ras Proteins/genetics
Substrate Specificity