Extracellular Vesicles Carrying miR-887-3p Promote Breast Cancer Cell Drug Resistance by Targeting BTBD7 and Activating the Notch1/Hes1 Signaling Pathway

Figure 5

miR-887-3p targeted BTBD7. (a) Venn map of the intersection of miR-887-3p downstream target genes predicted by RNAInter, Targetscan, and ENCORI databases. (b) Coexpression network of candidate genes. (c) miR-887-3p targeting site in BTBD7 3UTR predicted by Starbase. (d) Luciferase reporter plasmid containing BTBD7-wt or BTBD7-mut was transfected into 293T cells together with miR-887-3p in parallel with an miR-NC plasmid vector. (e) Enrichment of miR-887-3p on the BTBD7 was detected by RNA pull down assay, relative to antisense-oligos. (f) ECORI Pan-Cer assessed the BTBD7 expression in normal tissues and primary tumors. Relative BTBD7 mRNA expression (g) and protein level (h) in MCF-7, BT474, and HCC1937 cells were determined by RT-qPCR and western blot analysis under MDA-MB-231-derived EV treatment. The miR-887-3p was normalized to U6 while the BTBD7 was normalized to GAPDH. Data are expressed as the . One-way ANOVA and Tukey’s multiple comparison test were used. . Three independent experiments were performed. BC: breast cancer; miR: microRNA; wt: wild type; mut: mutant type; RT-qPCR: reverse transcription quantitative polymerase chain reaction; BTBD7: BTB domain containing 7; 3UTR: 3 untranslated region; CCK-8: cell counting kit-8; ANOVA: analysis of variance.

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