Cell cycle: Division enzyme regulates metabolism.

Abstract

Cell division requires the action of key regulator proteins called cyclins and CDKs. It emerges that a cyclin–CDK complex can regulate cell metabolism, and targeting this metabolic regulation causes tumour regression in mice. See Letter p.426 Cyclin–CDK complexes are commonly amplified in cancer and promote cell cycle progression. Inhibitors for CDK4/6 are being tested in clinical trials and are thought to work in patients that retain expression of the CDK substrate RB1. Here, the authors describe an additional pro-survival role of one cyclin–CDK complex, D3–CDK6, which controls cellular metabolism. When hyperactivated in cancer cells, the complex phosphorylates and inactivates two glycolysis enzymes. This redirects glycolytic intermediates to the pentose phosphate and serine pathways, providing enhanced antioxidant capacity. CDK4/6 inhibitors can induce apoptosis by increasing the oxidative stress in tumour cells expressing high levels of D3–CDK6 complexes. The findings suggest that, in addition to RB1, markers such as levels of D3–CDK6 complexes could be useful for identifying patients likely to respond to CDK4/6 inhibitors.