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Pancreatic ductal adenocarcinoma (PDAC) is characterised by immune evasion that contribute to poor prognosis. Cancer‐associated fibroblasts (CAFs) play a pivotal role in orchestrating the PDAC tumour microenvironment. We investigated the role of CAF‐derived extracellular vesicle (EV)‐packaged long non‐coding RNAs (lncRNAs) in immune evasion and explored gene therapy using engineered EVs loading small interfering RNAs (siRNAs) as a potential therapeutic strategy. Our findings highlight the significance of EV‐packaged lncRNA RP11‐161H23.5 from CAF in promoting PDAC immune evasion by downregulating HLA‐A expression, a key component of antigen presentation. Mechanistically, RP11‐161H23.5 forms a complex with CNOT4, a subunit of the mRNA deadenylase CCR4‐NOT complex, enhancing the degradation of HLA‐A mRNA by shortening its poly(A) tail. This immune evasion mechanism compromises the anti‐tumour immune response. To combat this, we propose an innovative approach utilising engineered EVs as natural and biocompatible nanocarriers for siRNA‐based gene therapy and this strategy holds promise for enhancing the effectiveness of immunotherapy in PDAC. Overall, our study sheds light on the critical role of CAF‐derived EV‐packaged lncRNA RP11‐161H23.5/CNOT4/HLA‐A axis in PDAC immune evasion and presents a novel avenue for therapeutic intervention. [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal malignancies, highlighting the urgent need to elucidate the underlying oncogenic mechanisms. VIRMA is a classic isoform of methyltransferases that participates in epigenetic transcriptomic modification in eukaryotic mRNAs. However, the exact roles of VIRMA in PDAC remain unclear. Here, we identified that VIRMA is highly expressed in PDAC, and histone modifications of the promoter may partly account for this dysregulation. Moreover, VIRMA is closely related to glycolysis and poor prognosis in PDAC. We further determined that STRA6 is a direct downstream target of VIRMA in PDAC by RNA sequencing (RNA-seq) and m6A sequencing (m6A-seq). VIRMA is involved in gene expression regulation via 3' UTR targeting of STRA6 mRNA. Furthermore, the m6A reader IGF2BP2 was shown to critically contribute to the stability of STRA6 mRNA. We describe the role of VIRMA in promoting signaling via the STRA6/STAT3 axis, which results in increased levels of HIF-1α, a key activator of glycolysis. In vivo and in vitro experiments reveal that the VIRMA-STRA6-STAT3-HIF-1α axis plays an instrumental role in glycolysis and tumor progression in PDAC. In conclusion, we demonstrate that VIRMA can increase glycolysis in PDAC by upregulating STRA6, a cell surface membrane protein that stimulates the STAT3 pathway, thereby activating HIF-1α and leading to pancreatic cancer malignancy. Overall, our data strongly suggest that the VIRMA-STRA6-STAT3-HIF-1α axis is a viable therapeutic target in PDAC. • Unveiling the Role of VIRMA: This study investigates the impact of the m6A writer VIRMA on glycolysis and tumor progression in pancreatic ductal adenocarcinoma (PDAC). • Identification of Downstream Target: STRA6 emerges as a critical downstream target of VIRMA in PDAC, providing a molecular link between the m6A writer and glycolytic reprogramming. • Molecular Insights: VIRMA collaborates with IGF2BP2 to stabilize STRA6 mRNA in an m6A-dependent manner, fostering high expression of STRA6, a membrane protein implicated in tumor malignancy. • Signaling Cascade Activation: VIRMA-induced activation of the STRA6/STAT3/HIF-1α signaling cascade is demonstrated, showcasing the molecular events contributing to glycolysis and tumor proliferation. • Therapeutic Implications: The identified VIRMA-STRA6-STAT3-HIF-1α axis presents a potential therapeutic target for pancreatic cancer, offering new avenues for intervention and treatment strategies. [ABSTRACT FROM AUTHOR]

Glycolytic metabolism is a hallmark of pancreatic ductal adenocarcinoma (PDAC), and tumor-associated stromal cells play important roles in tumor metabolism. We previously reported that tumor-associated macrophages (TAMs) facilitate PDAC progression. However, little is known about whether TAMs are involved in regulating glycolysis in PDAC. Here, we found a positive correlation between CD68+ TAM infiltration and FDG maximal standardized uptake (FDG SUVmax) on PET-CT images of PDAC. We discovered that the glycolytic gene set was prominently enriched in the high TAM infiltration group through Gene Set Enrichment Analysis using The Cancer Genome Atlas database. Mechanistically, TAMs secreted IL-8 to promote GLUT3 expression in PDAC cells, enhancing tumor glycolysis both in vitro and in vivo, whereas this effect could be blocked by the IL-8 receptor inhibitor reparixin. Furthermore, IL-8 promoted the translocation of phosphorylated STAT3 into the nucleus to activate the GLUT3 promoter. Overall, we demonstrated that TAMs boosted PDAC cell glycolysis through the IL-8/STAT3/GLUT3 signaling pathway. Our cumulative findings suggest that the abrogation of TAM-induced tumor glycolysis by reparixin might exhibit an antitumor impact and offer a potential therapeutic target for PDAC. • FDG uptake in PDAC patient is positively correlated with CD68+ TAM infiltration. • TAM reprograms glycolytic metabolism of PDAC cell via IL-8/STAT3/GLUT3 axis. • IL-8 receptor inhibitor (reparixin) reverses PDAC glycolysis and tumor growth. [ABSTRACT FROM AUTHOR]