Loss of SUV420H2 promotes EGFR inhibitor resistance in NSCLC through upregulation of MET via LINC01510

Epidermal growth factor receptor inhibitors (EGFRi) are standard-of-care treatments administered to patients with non-small cell lung cancer (NSCLC) that harbor EGFR alterations. However, development of resistance within a year post-treatment remains a major challenge. Multiple mechanisms can promote survival of EGFRi treated NSCLC cells, including secondary mutations in EGFR and activation of bypass tracks that circumvent the requirement for EGFR signaling. Nevertheless, mechanisms involved in bypass track activation are understudied, and in a subset of cases the mechanisms are unknown. The findings from this study identified an epigenetic factor, SUV420H2 that when lost drives resistance of NSCLC to multiple EGFRi, including erlotinib, gefitinib, afatinib, and osimertinib. SUV420H2 catalyzes trimethylation of histone H4 lysine-20, a modification required for gene repression and maintenance of heterochromatin. Here we show that loss of SUV420H2 leads to upregulation of an oncogenic long non-coding RNA, LINC01510 that promotes transcription of the oncogene MET, a component of a major bypass track involved in EGFRi resistance. SignificanceDue to an incomplete understanding of the mechanisms involved in promoting resistance to EGFRi, patients often succumb to their disease. Here we identified a global mediator of EGFRi resistance, SUV420H2 that helps to uncover an additional mechanism involved in resistance driven via a major bypass track involving the protooncogene MET.