Fig. 3: Tumor accumulation and anticancer ability of siRNA2@HPVP.

a In vivo tumor-targeting capacity of HPVP on 4T1 tumor-bearing mice after i.v. injection. The blockade of α6 integrin with antibody reduced the tumor accumulation of HPVP. A representative image of three biological replicates is shown. b Ex vivo immunofluorescence images for the evaluation of PDL1 inhibition effect of siRNA1@HPVP, siRNA2@HPVP, and siRNA3@HPVP (Scale bar: 1 mm). A representative image of three biological replicates is shown. c Bioluminescence assay for the in situ measurement of innate immunity in 4T1 tumors after treated with siRNA2@HPVP. Tumor cells were transfected with a pTNF-α-promoter-luc plasmid for reporting the intratumoral TNF-α level. A representative image of three biological replicates is shown. d In vivo anticancer effect evaluation of siRNA2@HPVP and HPVP + aPDL1 on the subcutaneous murine breast tumor model. The tumor size was measured every other day. Five biological replicates are shown. e FACS analysis for measuring the expression of PDL1 protein in PBS- or siRNA2@HPVP-treated mice tumors. Three biological replicates are shown. f Quantitative analysis of Ki67⁺ tumor cells after different treatments. Four images per group were taken. g FACS data of the mature DCs (CD11c⁺CD80⁺CD86⁺) within lymph nodes (left) and tumor-infiltrating cytotoxic T cells (CD3⁺CD8⁺ T cells, right) after different treatments. Three biological replicates (right) and four biological replicates (left) are shown, respectively. h FACS analysis for measuring intratumoral M1/M2 macrophages ratio after different treatments. CD11b⁺CD206⁺ cells were defined as M2 macrophages, while CD11b⁺CD206⁻ cells were defined as M1 macrophages. Four biological replicates are shown. i IFN levels in the serum from the mice 12 h after different treatments. Three biological replicates are shown. Statistical significance was calculated via one-way ANOVA with a Tukey post-hoc test (d–i). Data are presented as mean values ± SD.