CDK/cyclin dependencies define extreme cancer cell-cycle heterogeneity and collateral vulnerabilities

SUMMARY

Progression through G1/S phase of the cell cycle is coordinated by cyclin-dependent kinase (CDK) activities. Here, we find that the requirement for different CDK activities and cyclins in driving cancer cell cycles is highly heterogeneous. The differential gene requirements associate with tumor origin and genetic alterations. We define multiple mechanisms for G1/S progression in RB-proficient models, which are CDK4/6 independent and elicit resistance to FDA-approved inhibitors. Conversely, RB-deficient models are intrinsically CDK4/6 independent, but exhibit differential requirements for cyclin E. These dependencies for CDK and cyclins associate with gene expression programs that denote intrinsically different cell-cycle states. Mining therapeutic sensitivities shows that there are reciprocal vulnerabilities associated with RB1 or CCND1 expression versus CCNE1 or CDKN2A. Together, these findings illustrate the complex nature of cancer cell cycles and the relevance for precision therapeutic intervention.

Graphical abstract

In brief

Knudsen et al. find that there is extensive heterogeneity in the requirement for CDK and cyclins across cancer models. Multiple biochemically distinct mechanisms drive cell division. Divergent cell-cycle states harbor distinct genetic and pharmacological vulnerabilities, suggesting that cell-cycle diversity could be exploited for a precision approach to cancer therapy.