Abstract 3281: Silencing of necroptosis related genes in endocrine-resistant breast cancer cells causes PFKFB3 induced arrest of necroptosis and contributes to resistance

Abstract Approximately 70% of newly diagnosed breast cancer patients are estrogen receptor positive. Patients treated with approved treatment strategies may develop resistance to these therapies. Because of this problem in treatment, new treatment regimens need to emerge. Altered reprogramming of metabolism and an intense dependence on glycolysis are hallmarks of cancer, which is necessary to support the high energy demand of rapidly proliferating cancer cells. Rapidly dividing cancer cells are known to have increased energy requirements and altered reprogramming of glucose metabolism, leading to an increased reliance on glycolysis. The conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, a critical rate-limiting step in the glycolysis pathway, is greatly influenced by an allosteric activator produced by the enzyme PFKFB3 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3), thus making PFKFB3 an important regulator of glycolytic flux. Furthermore, PFKFB3 has been shown to be overexpressed in many human cancers, including breast cancer, and upregulated by estrogen. In our previous studies, we have shown that endocrine-resistant BC cells growth is strongly reduced by PFKFB3 targeting using PFKFB3 inhibitors, glucose uptake is reduced, triggered to necroptosis by RIPK1 and MLKL phosphorylation, and PFKFB3 inhibition reduces tumor size in mouse xenografts. In this study, we showed that silencing of RIPK1 and MLKL, genes involved in necroptosis, by siRNAs followed by inhibition of PFKFB3 by PFK158 did not induce necroptosis in endocrine-resistant BC cells. Furthermore, we further confirmed that phosphorylation of MLKL and RIPK occurs with PFKFB3 inhibition. In summary, this study reveals that necroptosis induced by PFKFB3 inhibition contributes to resistance by arresting necroptosis in endocrine-resistant BC cells after silencing of necroptosis-related genes. Citation Format: Brandon C. Jones, Tuna Onal, Surojeet Sengupta, Catherine M. Sevigny, Lu Jin, Paula R. Pohlmann, Ayesha Shajahan-Haq, Robert Clarke. Silencing of necroptosis related genes in endocrine-resistant breast cancer cells causes PFKFB3 induced arrest of necroptosis and contributes to resistance [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 3281.