Abstract 2643: TNFAIP2 interacts with EGFR to modulate EGF-induced EGFR auto-phosphorylation and internalization and sequential ERK1/2 activation in nasopharyngeal carcinoma cells

Abstract

Abstract TNFAIP2 (TNF-α-inducible protein 2) is identified as an angiogenic and proinflammatory factor and is essential for formation of tunneling nanotubes connecting between remote cells. Cancer-associated TNFAIP2 overexpression is first demonstrated in nasopharyngeal carcinoma (NPC) and is significantly correlated with poor survival of patients. We previously revealed that TNFAIP2 is associated with actin filaments, inducing actin remodeling and membrane protrusion and promotes cell motility of NPC cells. To elucidate functional roles of TNFAIP2 in cancer progression, we exploited co-immunoprecipitation (co-IP) coupled with mass spectrometry (MS)-based proteomic analysis to identify interacting proteins of TNFAIP2 in NPC cells. Epidermal growth factor (EGF) receptor (EGFR) is one of the identified candidates and is frequently overexpressed in various cancer types. We validated the interaction between TNFAIP2 and EGFR in two types of NPC cell lines; nevertheless, the interaction of TNFAIP2 with EGFR was reduced along with EGF stimulation. Reciprocal domain mapping analyses and immunofluorescence staining further demonstrated that the C-terminal amino acid residues 461-520 of TNFAIP2, which are dispensable for its association with the plasma membrane, are required for TNFAIP2 interaction with EGFR. On the other hand, the intracellular juxtamembrane domain (amino acids 645-689) and kinase domain (amino acids 690-945) of EGFR are needed for its interaction with TNFAIP2. Furthermore, EGF-triggered internalization of EGFR was significantly interfered in TNFAIP2-knockout NPC cells generated using the CRISPR-Cas9 system, accompanied by alleviated auto-phosphorylation of EGFR on the 1068 and 1173 tyrosine residues and subsequent activation of downstream ERK1/2. This impairment of liganded EGFR-transduced signaling in TNFAIP2-knockout NPC cells was correlated with a decrease in cell migration as revealed by transwell migration assays. These data collectively reveal a novel role of TNFAIP2 in modulation of EGF-triggered EGFR activation and sequential signaling transduction through protein-protein interactions. Efforts are made to pursue if the aforementioned events involve modulation of EGFR oligomerization or recruitment of internalized activated EGFR into endosomes. The results could shed light on how TNFAIP2 promotes cancer progression via coordinating with EGFR and the impact of TNFAIP2 on EGFR-targeted cancer therapy. Citation Format: Hao-Ping Liu, Chih-Ching Wu. TNFAIP2 interacts with EGFR to modulate EGF-induced EGFR auto-phosphorylation and internalization and sequential ERK1/2 activation in nasopharyngeal carcinoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2643.