Abstract 4180: Insights into HuR as a modulator of aerobic glycolysis in triple-negative breast cancer

Abstract The RNA-binding protein Human Antigen R (HuR/ELAVL1) is ubiquitously expressed and plays a pivotal role in post-transcriptional gene regulation by stabilizing and enhancing the translation of mRNAs containing U/AU-rich elements. Its overexpression, particularly in the cytoplasm, has been implicated in various cancers, where it drives critical processes such as proliferation, survival, angiogenesis, and metastasis. As a key modulator of oncogenic pathways, HuR represents a significant target for understanding cancer progression and developing novel therapeutic strategies. The present study investigates the oncogenic role of HuR in TNBCS, an aggressive subtype of breast cancer. Meta-analysis with TNBC dataset (Liu-2014) correlated high HuR protein expression with reduced patient survival (p=0.028). Immunohistochemistry performed in 40 TNBC patient tissue showed an overexpression of HuR (77%) and its downstream target MMP9(55%). Disrupting the RNA binding activity of HuR with the HuR specific inhibitor CMLD2 resulted in the downregulation of HuR and its downstream targets CDK2, MMP9, and β-catenin in TNBC cell lines MDA-MB-231 and MDA-MB-468. Inhibition of cytoplasmic HuR was validated via immunofluorescence and cell fractionation followed by immunoblotting. HuR inhibition compromised proliferation, migration, invasion, extracellular acidification, clonogenicity (2D and 3D), and EMT (downregulated E-Cadherin, N-Cadherin, and Vimentin) in TNBC cells. Exploratory transcriptomics via nCounter XT showed that HuR inhibition in MDA-MB-231 altered the profile of glycolytic genes in addition to other pathways such as cell cycle, DNA damage repair, amino acid synthesis etc. In accordance, the expression of the glycolytic genes LDHA, PFKP and MCT4 was reduced upon CMLD2 treatment at mRNA and protein level in both the TNBC cell lines. Pretreatment with CMLD2 impaired the tumor forming ability of 4T1 in vivo. Consistent results were obtained on HuR siRNA knockdown. To our knowledge, this is the first report that explores HuR as a positive regulator of aerobic glycolysis in TNBCs. Inhibition of HuR by CMLD2 provides a rationale to consider it as a potential anticancer agent for TNBCs. Citation Format: Arundhathi Dev J R, Ajay Gogia, Sandeep R. Mathur, Ashutosh Mishra, Chandra Prakash Prasad. Insights into HuR as a modulator of aerobic glycolysis in triple-negative breast cancer [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 4180.