Fig. 3.

MiR-181a overexpression leads to Olaparib resistance and downregulates STING. A–C Quantification by RT-qPCR of miR-181a levels in miR-181a-OV and empty vector (CTRL) MDA-MB-436 (A), HCC1395 (B), and HCC1937 (C) cell lines (Student’s t-test). D Western blotting analysis for STING and β-actin (loading control) comparing miR-181a-OV and empty vector (CTRL) in MDA-MB-436, HCC1395, and HCC1937 cell lines. E–G Drug sensitivity assays comparing miR-181a-OV and empty vector (CTRL) in MDA-MB-436 (E), HCC1395 (F), and HCC1937 (G) cell lines, treated with different concentrations of olaparib (Two-way ANOVA and Sidak’s multiple comparisons test). H Western blotting analysis for STING, TBK1, cGAS, and β-actin (loading control), comparing miR-181a-OV and empty vector (CTRL) HCC1937 cell lines with or without olaparib treatment. I Western blotting analysis for STING and β-actin (loading control) comparing parental and OlaR in MDA-MB-436, HCC1395, and HCC1937 cell lines. J Western blotting analysis for STING and β-actin (loading control) comparing parental and OlaR HCC1937 cell line in resting and olaparib-treated (24 and 48 h) conditions. K Western blotting analysis for STING and β-actin (loading control) comparing parental and OlaR HCC1937 cell line in resting and cisplatin-treated (12 and 24 h) conditions. L, M Representative images of STING IHC (L) and miR-181a ISH (M) for TNBC tumor tissues in the TMA. Images of cases 1 and 2 (STING low, miR-181a high) and cases 3 and 4 (STING high, miR-181a low). N Comparison of STING protein levels in low versus high miR-181a TNBC tumor tissues in the TMA (Student’s t-test). *p < 0.05, **p < 0.01, ***p < 0.001. Cell viability assays were performed in triplicates