CDK8 Kinase Activity Promotes Glycolysis

Aerobic glycolysis, also known as the Warburg effect, is a hallmark of cancerous tissues. Despite its importance in cancer development, our understanding of mechanisms driving this form of metabolic reprogramming is incomplete. We report here an analysis of colorectal cancer cells engineered to carry a single point mutation in the active site of the Mediator-associated kinase CDK8, creating hypomorphic alleles sensitive to bulky ATP analogs. Transcriptome analysis revealed that CDK8 kinase activity is required for the expression of many components of the glycolytic cascade. CDK8 inhibition impairs glucose transporter expression, glucose uptake, glycolytic capacity and reserve, as well as cell proliferation and anchorage-independent growth, both in normoxia and hypoxia. Importantly, CDK8 impairment sensitizes cells to pharmacological glycolysis inhibition, a result reproduced with Senexin A, a dual inhibitor of CDK8/CDK19. Altogether, these results contribute to our understanding of CDK8 as an oncogene, and they justify investigations to target CDK8 in highly glycolytic tumors.