Coordinated DNA methyltransferase 3A and methyltransferase-like 7A activity reprograms the tumor microenvironment through discoidin domain receptor 1 signalingOA

Objective:Breast cancer is the most common malignancy in women and is characterized by a high recurrence rate that severely impacts patient survival.Regulatory T cells(Tregs)in the tumor microenvironment(TME)promote immune evasion and metastasis,increasing recurrence risk.This study determined how the epigenetic regulators,DNMT3A and METTL7A,modulate Treg infiltration via the DDR1/STAT3/CXCL5 axis and influence breast cancer recurrence and prognosis.Methods:RNA sequencing(RNA-seq)was used to identify differentially expressed genes(DEGs),followed by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment.Machine learning algorithms,including least absolute shrinkage and selection operator(LASSO),supported vector machine-recursive feature elimination(SVM-RFE)and ElasticNet identified DDR1 as a key gene.Validation included RT-qPCR,western blot,MSP,MeRIP-qPCR,and Co-IP to assess epigenetic regulation.Functional assays(CCK-8,Transwell,and Treg differentiation/chemotaxis)and xenograft models evaluated the role of DDR1 in tumor progression and recurrence.Results:DNMT3A upregulated DDR1 via DNA methylation,while METTL7A enhanced DDR1 mRNA stability via m6A modification.Co-regulation activated the DDR1/STAT3/CXCL5 axis,which boosted cancer cell proliferation,migration,and invasion.CXCL5 secretion increased Treg infiltration and accelerated tumor growth in vivo.DDR1 silencing reversed these effects,confirming that DDR1 has a pivotal role in breast cancer recurrence.Conclusion:DNMT3A and METTL7A were shown to cooperatively regulate DDR1 via DNA/m6A methylation,which drives Tregmediated immune suppression and recurrence.This study provided novel insights and therapeutic targets for breast cancer prognosis and treatment.