Fig 1: In vivo therapeutic effect of 3WJ-B-α9-apt-anti-miR-21 RNA nanoparticles in TNBC-PDX mice(A) NSG mice bearing TNBC-PDX xenografts were treated i.v. with 3WJ-B-α9-apt-anti-miR-21 (green), 3WJ-B-α9-apt-anti-scr (red), and PBS (black) every other day five times in total (20 μmol/L solution, 100 μL, indicated by arrows). Tumor volume (mm3) and body weight (g) were monitored during treatment. Representative images of BC tumors harvested from mice after treatment are shown on the right. (B) In vivo delivery of anti-miR-21 was analyzed by quantitative real-time PCR on mRNA isolated from 3WJ-B-α9-apt-anti-miR-21-treated tumors. The endogenous control U6 snRNA normalized the mRNA levels of miR-21. n = 4 independent samples. Statistics were calculated by two-tailed unpaired t test and presented as mean ± SD (∗p < 0.05, ∗∗p < 0.01, comparing 3WJ-B-α9-apt-anti-miR-21 with 3WJ-B-α9-apt-anti-scr and PBS, respectively). (C) Western blot examined the downstream protein expression of PTEN, PDCD4, p21, and p27 resulting from miR-21 silencing in nanoparticle-treated tumor extracts. Quantitative analyses are shown on the right, using GAPDH as an internal control. n = 3 independent samples. Statistics were determined by two-tailed unpaired t test and presented as mean ± SEM (∗∗p < 0.01, ∗∗p = 3.78 × 10−3 of PTEN and 1.67 × 10−3 of PDCD4 comparing 3WJ-Bα9-apt-anti-miR-21 with PBS). (D) Tumor growth inhibition and apoptosis induction of 3WJ-B-α9-apt-anti-miR-21 in TNBC-PDX tumor tissues. Cells stained positively by Ki-67 IHC and TUNEL assay are brown. (E) Histological examination of the organ toxicity of 3WJ-B-α9-apt-anti-miR-21 in the liver and kidneys by H&E staining. Scale bars, 10 μm (D and E).