RNA-seq of HER2-positive breast cancer BT474 cell line in response to KDM5 ihibition

Alterations in the histone methylation profiles are observed in various types of cancer and targeting of this epigenetic process has therapeutic potential. Here we provide proof-of-principle that pharmacological targeting of KDM5 histone-demethylases is a new strategy for the personalized treatment of HER2-positive breast cancer. This analysis demonstrates that cells characterized by HER2-positivity are particularly sensitive to KDM5 inhibition. The results are confirmed in an appropriate in vivo model with a close structural analogue (KDM5-inh1A). In selected HER2-positive breast cancer cells, we demonstrate synergistic interactions between KDM5-inh1 and HER2-targeting agents (trastuzumab and lapatinib). In addition, HER2-positive cell lines showing innate/acquired resistance to trastuzumab show sensitivity to KDM5-inh1. The levels of KDM5A/B/C proteins, which are selectively targeted by the agent, have no significant association with KDM5-inh1 responsiveness across our panel of breast cancer cell lines, suggesting the existence of other determinants of sensitivity. Using RNA-sequencing data of the breast cancer cell lines, we generate a gene-expression model, consisting of fifteen genes, which is a robust predictor of KDM5-inh1 sensitivity. In a test set of breast cancers, this model correctly predicts sensitivity to the compound in a large fraction of HER2+ tumors. In conclusion, KDM5 inhibition has potential in the treatment of HER2+ breast cancer and our gene-expression model can be developed into a diagnostic tool to select patients who may benefit from treatments based on KDM5-inhibitors.