Fig. 5: Oncogenic KRAS markedly decreases miR-29b-3p expression, leading to DNMT3b upregulation to inhibit RT-induced STING expression.

A CoLo320-Vec. and CoLo320-KRAS^G12D cells were harvested for miRNA-seq and identified miR-29b-3p as the potential candidate to regulate DNMT3b expression. B The level of miR-29b-3p was evaluated in KRAS-mutated cell lines in CCLE and TCGA-COAD database. One-way ANOVA t test. C The level of miR29b-3p was evaluated in HT29-KRAS^G12D and CoLo320-KRAS^G12D cells, compared to their parental KRAS^WT cells. One-way ANOVA t test. *p < 0.05. D The level of miR-29b-3p was evaluated in SW620^shKRAS and HCT116^shKRAS cells, compared to their parental KRAS^Mut cells. One-way ANOVA t test. *p < 0.05 and ***p < 0.001. E HT29-KRAS^G12D cells were transfected with miR-29b mimetic (20 nM) for 24 hr and then irradiated (5 Gy). After 24 hr, cells were harvested for qRT-PCR (n = 3). One-way ANOVA t test. *p < 0.05 and **p < 0.01. F SW620^shKRAS cells were transfected with miR-29b-3p antagomir (20 nM) for 24 hr and then irradiated (5 Gy). After 24 hr, cells were harvested for qRT-PCR (n = 3). One-way ANOVA t test. *p < 0.05 and **p < 0.01. G HT29-KRAS^G12D cells were transfected with miR-29b-3p mimetic (20 nM) for 24 hr and then irradiated (5 Gy). After 24 hr, cells were harvested for immunoblotting (n = 3). One-way ANOVA t test. **p < 0.01. H SW620^shKRAS cells were transfected with miR-29b-3p antagomir (20 nM) for 24 hr and then irradiated (5 Gy). After 24 hr, cells were harvested for immunoblotting (n = 3). One-way ANOVA t test. **p < 0.01.