Fig. 5: PCL-CP NPs target and penetrate tumor through CD44 mediated transcytosis.

a NIRF whole body imaging, ex vivo imaging of CD44 WT or KO tumor-bearing CD44 WT or KO mice at 24 h following i.v. administration of DiR-loaded, Cy5.5-labled PCL-CP NPs. b Quantification of ex vivo imaging data from (a). n = 3 animals. c Fluorescence images of frozen tumor core sections from CD44 WT or KO tumor grown on CD44 WT or KO mice at 24 h after treatment with Cy5.5-labled PCL-CP NPs. CD31 was stained with FITC-labeled antibody to show the endothelial cells. Bar = 50 μm. d Biodistribution of DOX loaded in DOX/pre-siRNA-coloaded PCL-CP NPs in CD44 WT or KO tumor-bearing CD44 WT or KO mice at 24 h following i.v. administration. n = 3 independent samples. e Quantitative analysis of biodistribution of DOX in (d). n = 3 independent samples. f Illustration of transwell study. The figure is created with BioRender.com. Transwell assay of transmigration of Cy5.5 labeled PCL NPs, PCL-C NPs or PCL-CP NPs (with or without pretreatment with a transcytosis inhibitor) across HUVEC cells (g), CT26 cells (h), CD44 KO HUVEC cells (i), or CD44 KO CT26 cells (j). Fluorescence intensity of the medium in the lower chamber was measured to calculate the percentage of transmigration at indicated time points. n = 3 independent experiments. k Confocal z-stack images of CT26 tumor cell spheroids after 18 h incubation with Cy5.5-labeled PCL NPs, PCL-C NPs or PCL-CP NPs (with or without pretreatment with a transcytosis inhibitor). White circles highlight the efficient penetration of CS-coated NPs. Bar = 150 μm. l Confocal z-stack images of the middle sections of CD44 WT or KO CT26-GFP spheroids after 18 h incubation with Cy5.5-labeled PCL-CP NPs. Bar=200 μm. m Proposed role of the CD44 in tumor ECs and tumor cells in mediating tumor targeting and penetration of CS-coated NPs. The figure is created with BioRender.com. Data are presented as mean ± s.e.m. in (b, d, g, h, i, j). Statistical analysis was performed by one-way ANOVA with Tukey’s post hoc test for comparison in (b, d, i, j). Data are representative of two independent experiments in (a–e, k, l) and three independent experiments in (g–j). Source data are provided as a Source Data file for (b, d, e, g, h, i, j).