The 3D Genomic Landscape of Differential Response to EGFR/HER2 Inhibition in Endocrine-Resistant Breast Cancer [RNA-seq]

Recent studies suggested that crosstalk between ERα and EGFR/HER2 pathways plays a critical role in mediating endocrine therapy resistance. Several targeting EGFR/HER2 signaling inhibitors including FDA-approved lapatinib and gefitinib as well as a novel dual tyrosine kinase inhibitor (TKI) sapitnib showed greater inhibitory efficacies. However, how a 3D chromatin landscape of the response to the inhibition to EGFR/HER2 pathway remains to be elucidated. In this study, we conducted in situ Hi-C and RNA-seq in two ERα+ breast cancer cell systems, tamoxifen-sensitive MCF7 and T47D and tamoxifen-resistant MCF7TR and T47DTR before and after the treatment of sapitnib. We identified differential response of topologically associated domains (TADs), looping genes and expressed genes. Interestingly, we found that many differential TADs and looping genes are reversible, indicating that EGFR/HER2 signaling may play a role in reshaping and rewiring the high order genome organization. We further examined and recapitulated the reversible looping genes in 3D spheroids of breast cancer cells. Our data provides a rich resource for further evaluating chromatin structural response to anti-EGFR/HER2 targeted therapies in endocrine-resistant breast cancer. RNA-seq experiment of 6 cell types with or without drugs, 3 biological replicates for each condition;