Abstract 4264: The TWEAK-Fn14-NF-kB signaling axis enhances expression of integrin AVB3 in a post-chemotherapy tumor microenvironment
Authors: Olazaba Omar Lujano , Robinson Mikella , Gallo Cecilia , Shammas Mena , Shelby Katelyn , Cruz Luisjesus , Gilbert Samuel F. , House Carrie D. 
Published: March 2024

Abstract
High grade serous ovarian cancer (HGSOC) patients initially respond to chemotherapy but a majority relapse with chemoresistant disease. Research supports the notion that tumor-initiating cells (TICs), a subpopulation of drug resistant stem-like tumor cells, are responsible for facilitating relapse and therapies targeting these fecund cells may prolong remission. The tumor microenvironment (TME) plays a crucial role in therapy resistance, and tumor relapse. Cytotoxic chemotherapies have been shown to modify the stroma of the TME which may favor the survival of TICs displaying specific adhesion proteins. We and others have shown that NF-kB transcription factors RelA and RelB respond to signals from the ovarian TME to promote proliferation, chemoresistance, and survival. Our results further show that RelA and RelB regulate expression of specific integrins. Recently we found that TNF-like inducer of apoptosis (TWEAK), a cytokine involved in tissue repair, and its only known receptor Fn14, are enriched following chemotherapy, leading to enhanced chemoresistance and survival of TICs. TWEAK also induces expression of specific integrins in ovarian TICs. Therefore, we hypothesize that NF-kB mediated integrin expression enables adhesion and survival of TICs to a chemotherapy modified extracellular matrix (ECM) to facilitate tumor repopulation and relapse. Using magnetic activated cell sorting (MACS) for CD117+ TICs, we found that a significant majority are enriched for integrin AVB3. Supporting a role for TWEAK-Fn14-NF-kB in mediating integrin expression we further show that integrin AVB3, but not AVB5 or A5B1, was significantly increased in CD117+ TICs in the presence of TWEAK and was dependent on Fn14 as demonstrated through knockdown experiments. RNA-sequencing analysis of tumor cells grown in spheroid conditions with RelA or RelB shRNA knockdown relative to control, show ITGAV is dependent on RelA while ITGB3 expression is dependent on RelB. Taken together, our findings suggest CD117+ TICs have enhanced expression of AVB3 and is further induced by TWEAK mediated NF-kB activity for adaptation to a stressful post-chemotherapy environment. Ongoing in vitro and in vivo studies are investigating the therapeutic benefit of targeting AVB3 or TWEAK in CD117+ TICs for prevention of adhesion and tumor repopulation following chemotherapy. These studies will uncover interactions between TICs and ECM through their unique expression of integrins and clarifies the role of NF-kB transcription factors RelA and RelB in regulating TIC survival in the post-chemotherapy TME.
Citation Format: Omar Lujano Olazaba, Mikella Robinson, Cecilia Gallo, Mena Shammas, Katelyn Shelby, Luisjesus Cruz, Samuel F. Gilbert, Carrie D. House. The TWEAK-Fn14-NF-kB signaling axis enhances expression of integrin AVB3 in a post-chemotherapy tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4264.