Abstract 3782: Nuclear expulsion-derived extracellular vimentin accelerates CD8+ T cell dysfunction and enhances treatment resistance

Abstract Treatment resistance and relapse remain significant challenges in cancer therapy including chemotherapy, radiation, small-molecule inhibitors, and immunotherapy. While these treatments induce considerable apoptotic cell death, the complete range of apoptotic signals and their "off-target effects" on surviving cancer cells are not well understood. Our previous studies uncovered that apoptotic cancer cells with high levels of Peptidyl Arginine Deiminase 4 (Padi4) undergo nuclear expulsion, releasing DNA/protein complexes (Nuclear Expulsion Products; NEPs) into the extracellular space, which are critical for metastatic outgrowth. Here, we report that chemotherapy and radiotherapy trigger nuclear expulsion in Padi4-positive tumors, which in turn facilitates therapy resistance. Immune profiling revealed increased CD8+ T cell infiltration and activation in Padi4high tumors, which is characterized by elevated expression of PD1, GrnzB, IFNg, and Ki-67. Cisplatin treatment further amplified these responses, ultimately leading to CD8+ T cell exhaustion, exhibiting TIM3. Notably, CD8+ T cells were shown to be essential for nuclear expulsion-mediated therapy resistance, as demonstrated by experiments using CD8 neutralizing antibodies. Proteomic analysis and coculture assays identified extracellular citrullinated vimentin (citVIM) as a major NEP component, acting as a Damage-Associated Molecular Pattern (DAMP), which directly facilitated CD8+ T cell hyperactivation and contributed to rapid exhaustion. Through co-culture assays using TLR4-deficient CD8+ T cells and NEPs, we further demonstrated that TLR4 serves as a crucial binding partner of vimentin, linking NEP-derived vimentin to CD8+ T cell activation. In addition, citVIM was observed to enhance IFNγ production in CD8+ T cells, and IFNγ-primed 4T1 cells also demonstrated increased therapy resistance. These findings underscore CD8+ T cell-derived IFNγ as a critical downstream effector in therapy resistance and highlight the pivotal role of the citVIM-TLR4-IFNγ axis in nuclear expulsion-mediated chemoresistance. Collectively, our study reveals how apoptotic signals from cancer cells during therapy act as off-target effects, modulating host immunity, and demonstrate how cancer cells exploit these signals for survival. Furthermore, by elucidating the relationship between nuclear expulsion and T cells, this research provides a foundation for understanding how chemo- and radiotherapy could enhance the efficacy of immune checkpoint inhibitors (ICIs) Citation Format: Woo-Yong Park, Rachel Yang, Jae young So, Abdul Ahad, Yeap Ng, Balamurugan kuppusamy, Ronald holewinski, Roberto Weigert, Esta Sterneck, Thorkell Andresson, Li Yang. Nuclear expulsion-derived extracellular vimentin accelerates CD8+ T cell dysfunction and enhances treatment resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3782.