Abstract 4244: Using lysosomal immunogenic cell death to target cancer via xanthine oxidase

Abstract

Abstract Lysosome-induced immunogenic cell death (LIICD) is a powerful mechanism of targeting cancer cells that kills circulating malignant cells and primes the host’s immune cells against future remission. Current immunotherapies for cancer are limited in preventing recurrence - a gap which can be bridged by training the immune system to recognize cancer neoantigens. Lysosomal leakage can be induced therapeutically to traffic antigens from dying cells to dendritic cells which can later present those tumorigenic antigens to T cells. We demonstrate that the oxidative agent native bovine xanthine oxidase can induce early markers of lysosome-induced immunogenic cell death in an in vitro human cancer cell line (CCL2). Specifically, we measured overall cell death, as well as surface-expressed calreticulin, extracellular ATP release, and HMGB1 production. These markers are consensus indicators of ICD. Flow cytometry, luminescence assays, and ELISA were used respectively to quantify biomarker levels between treated versus untreated cells. We also included a positive control group of cells dosed with doxorubicin (a known inducer of LIICD). We looked at each marker at various time points after cancer cells were treated with xanthine oxidase, doxorubicin, and an untreated group. Upregulated biomarkers after treatment with the protein indicate an immunogenic response. Further, we used confocal imaging to show lysosomal membrane permeabilization after treatment with Native Bovine Xanthine Oxidase using Lucifer Yellow staining. We thus show the potential for this protein to induce an anticancer effect paired with an adaptive immune response against tumor cells. Our research in human cell lines here provides evidence for the success of the same therapeutic method in patients and serve as the gateway to developing a new treatment approach against breast cancer. Citation Format: Iulianna Taritsa, Eric Fossel, Kuldeep Neote. Using lysosomal immunogenic cell death to target cancer via xanthine oxidase [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 4244.