EFO2 promotes triple-negative breast cancer progression and reduces CD8+ T cell-mediated killing by acetylating USF1 to enhance SLC2A1-mediated glycolysis.
A novel EFO2/USF1/SLC2A1 signaling axis that modulates glycolytic metabolism and CD8⁺T cell cytotoxicity is identified, positioning EFO2 as a promising therapeutic target for TNBC treatment.
Abstract
Triple-negative breast cancer (TNBC) is an aggressive subtype characterized by significant intratumoral heterogeneity and poor prognosis. Our study identified Establishment Factor-Like Protein 2 (EFO2) as a key oncogenic driver of TNBC progression. Using GEO datasets, we identified differentially expressed genes in TNBC. Functional roles of EFO2 were assessed via knockdown in human (MDA-MB-231, HCC1937) and mouse (4 T1, EMT6) TNBC cells, examining proliferation, glycolysis, and co-culture with CD8⁺ T cells. In vivo tumor growth was evaluated. Molecular mechanisms were investigated through co-immunoprecipitation, mutagenesis, luciferase reporter, and ChIP-qPCR assays. We observed that EFO2 was highly expressed in TNBC tissues, and this high expression correlated with shorter patient survival. Functional experiments showed that EFO2 knockdown suppressed tumor growth and proliferation both in vitro and in vivo. Furthermore, EFO2 knockdown inhibited glycolysis, as evidenced by decreased glucose uptake, ATP production, and lactate production. Moreover, EFO2 deficiency enhanced CD8⁺ T cell-mediated cytotoxicity against TNBC cells. Mechanistically, we demonstrated that EFO2 promoted the acetylation of Upstream Transcription Factor 1 (USF1), thereby enhancing transcriptional upregulation of the SLC2A1 promoter, a key glucose transporter. This EFO2/USF1/SLC2A1 signaling axis accelerated glycolysis in TNBC cells, which concurrently sustained tumor proliferation and impaired CD8⁺ T cell effector function, reducing TNBC cell susceptibility to T cell-mediated killing. Our findings identify a novel EFO2/USF1/SLC2A1 signaling axis that modulates glycolytic metabolism and CD8⁺T cell cytotoxicity, positioning EFO2 as a promising therapeutic target for TNBC treatment.
The m6A methyltransferase METTL3 functions as a critical oncogenic driver in triple-negative breast cancer (TNBC). However, its specific downstream targets and mechanistic functions in less metastatic TNBC subtypes remain poorly characterized. To address this, we evaluated METTL3 expression and the phenotypic effects of its siRNA-mediated knockdown in normal mammary epithelial (MCF10A), low-metastatic TNBC (HCC1143), and high-metastatic TNBC (MDA-MB-231) cell lines. We assessed global m6A levels, cell viability, cell cycle progression, and migration. To uncover specific downstream pathways, transcriptomic profiling was performed on HCC1143 cells, followed by RT-qPCR validation and m6A site prediction. METTL3 depletion reduced global m6A levels and cell viability across all cell lines. Notably, in low-metastatic HCC1143 cells, METTL3 knockdown induced a pronounced G2/M cell cycle arrest and dramatically impaired migratory capacity. Transcriptomic analysis of HCC1143 revealed altered expression of genes associated with the observed phenotypic changes. Specifically, critical transcripts harboring predicted m6A motifs, including LIMK1, CCNB2, and CDH1, were significantly dysregulated, pointing to potential alterations in pathways governing cytoskeletal remodeling, actin organization, and cell-cell adhesion. Taken together, we propose that METTL3 promotes cell viability and motility in low-metastatic TNBC by regulating key transcripts involved in cell cycle progression and actin dynamics. Significance Statement Epitranscriptomic studies on TNBC predominantly focus on highly metastatic models, leaving less aggressive subtypes poorly understood. This study uniquely addresses this gap by investigating the function of METTL3 in HCC1143, a low-metastatic TNBC cell line, alongside aggressive TNBC cell lines. We discovered that METTL3 depletion uniquely triggers a severe halt in cell division (G2/M arrest) in HCC1143 cells, while universally disrupting actin-associated cell motility across different backgrounds. These findings demonstrate that METTL3 acts as a context-dependent modulator of cell fate rather than a monolithic driver. Ultimately, highlighting these distinct cellular responses underscores the need to consider specific molecular backgrounds when evaluating epitranscriptomic targets in heterogeneous cancers, such as TNBC.
Buket Sağlam-Şen, Azime Akçaöz-Alasar, Ahmet Batuhan Dondurur et al.· bioRxiv· 0 citations
The study demonstrates that TFEB regulates the expression of the multidrug efflux transporter ATP-binding cassette subfamily G member 2 (ABCG2), a crucial factor in drug resistance mechanisms, and targets TNKS represents a potentially effective therapeutic approach to address cisplatin resistance and improve treatment outcomes in TNBC.
Shariqa Jan, Kaneez Fatima, S. Khan et al.· Molecular Biology Reports· 0 citations
Interferon-induced transmembrane protein 3 (IFITM3) is best known as an antiviral protein, but accumulating evidence supports pro-tumorigenic functions across several cancers. Here, we examined IFITM3 in triple-negative breast cancer (TNBC). IFITM3 depletion suppressed MDA-MB-231 cell proliferation, migration, sphere formation, and xenograft tumor growth, whereas IFITM3 overexpression enhanced these phenotypes. IFITM3 depletion restored E-cadherin expression and increased membrane-associated E-cadherin-β-catenin complexes. These changes were accompanied by reduced nuclear active β-catenin and decreased Wnt/β-catenin transcriptional activity in cultured cells. Altered β-catenin localization was also observed in xenograft tumors. Conversely, IFITM3 overexpression enhanced WNT3a-responsive transcription and nuclear accumulation of active β-catenin. IFITM3 expression was elevated in breast tumors and was associated with shorter overall survival in a selected lymph-node-negative TNBC cohort. Together, these findings identify IFITM3 as a regulator of β-catenin localization and Wnt signaling that promotes epithelial-mesenchymal transition (EMT) and stem-like properties in TNBC cells.
Heeyeon Kim, Young-Ming Yu, Y-U Park et al.· Biochemical and Biophysical...· 0 citations
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