RUNX3

RUNX3 is a Runt-domain transcription factor that regulates gene expression through conserved RUNX-family DNA-binding architecture^[1]. Mechanistically, RUNX3 supports TGF-β/SMAD-dependent growth control in gastric epithelium, where Runx3 loss causes epithelial hyperplasia, increased proliferation, reduced apoptosis, and resistance to TGF-β responses^[2][3]. RUNX3 also restrains Wnt/β-catenin/TCF signaling in intestinal tumorigenesis by forming a complex with β-catenin/TCF4 and reducing Wnt target activity^[4]. In immune models, Runx3 establishes CD8⁺ tissue-resident memory T-cell differentiation, supports tissue-residency genes, suppresses tissue-egress genes, and improves tumor-specific CD8⁺ T-cell abundance in mouse tumors^[5]. Compared with related RUNX isoforms, RUNX3 is the smallest mammalian RUNX-family gene, while RUNX1, RUNX2, and RUNX3 share DNA-binding motifs and require regulated temporal and spatial expression^[1]. RUNX3 isoform biology is experimentally important because P1 and P2 promoters regulate RUNX3 expression in a cell-type-specific manner^[1]. In ovarian carcinoma models, RUNX3 transcript variants show distinct effects on platinum sensitivity, DNA repair, angiogenesis, and malignant phenotypes^[6].- RUNX3 links transcriptional control, TGF-β signaling, Wnt suppression, and immune residency programs.- Isoform-specific RUNX3 models support studies of platinum response, angiogenesis, and tumor biology.