CDK1 Interacts with Sox2 and Promotes Tumor Initiation in Human Melanoma.

: Cancers are composed of heterogeneous subpopulations with various tumor-initiating capacities, yet key stem cell genes associated with enhanced tumor-initiating capacities and their regulatory mechanisms remain elusive. Here, we analyzed patient-derived xenografts from melanoma, colon, and pancreatic cancer tissues and identified enrichment of tumor-initiating cells in MHC class I-hi cells, where CDK1, a master regulator of the cell cycle, was upregulated. Overexpression of CDK1, but not its kinase-dead variant, in melanoma cells increased their spheroid forming ability, tumorigenic potential, and tumor-initiating capacity; inhibition of CDK1 with pharmacologic agents reduced these characteristics, which was unexplained by the role of CDK1 in regulating the cell cycle.