Abstract LB096: EGFR-dependent inflammation as a driver of breast cancer

Abstract

Abstract Triple Negative Breast Cancer (TNBC) is one of the most aggressive and metastatic subtypes of hormone receptor negative breast cancers. Evidence supports that most patients with TNBC overexpress the Epidermal Growth Factor Receptor (EGFR), yet its role in driving the disease remains unclear. Therapies have been developed to target EGFR, but EGFR-targeted antibodies and tyrosine kinase inhibitors fail to work effectively in breast cancer patients. A possible explanation is that in addition to its canonical function at the membrane, EGFR has a non-canonical function where it can undergo retrograde trafficking to the nucleus, making it resistant to antibody-based therapeutics. Once in the nucleus, EGFR is known to function as a transcriptional cofactor for STAT3, STAT5, and E2F1, thereby regulating the expression of genes that promote inflammation and cell proliferation. Via RNA-Seq analysis, we demonstrate that EGFR can regulate different subsets of genes depending on its canonical signaling activity or nuclear role. Our goal is to understand and distinguish this difference in regulation to assess how EGFR affects inflammation. We hypothesize that EGFR is modifying inflammation differently depending on its canonical or non-canonical role, thereby driving disease progression in multiple ways. We have found that canonical EGFR can induce interleukin 8 while nuclear EGFR can repress interleukin 6 through the use of either kinase inhibitors (IL8) or blocking nuclear translocation of EGFR (IL6). Correlated with these changes are alterations in growth and inflammatory profiles in both a triple negative inflammatory mouse model and an EGFR-driven breast cancer mouse model. We are now investigating the role of nuclear-EGFR-dependent inflammation in driving tumor progression. Understanding the different mechanisms by which EGFR modifies inflammation and the tumor microenvironment would allow us to develop more specific targets for patients with TNBC. Citation Format: Angelica Escoto. EGFR-dependent inflammation as a driver of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB096.