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. Author manuscript; available in PMC: 2022 Apr 20.
Published in final edited form as: ACS Nano. 2022 Jan 31;16(2):1940–1953. doi: 10.1021/acsnano.1c05505

Figure 4.

Figure 4.

RGD-EV:siPDL1 targets and downregulates PD-L1 in GBM primed with RT. (A) Schematic of RGD-EV, Cy5.5 labeled, and loaded with cholesterol-modified siPDL1. (B,C) NTA (B) and TEM imaging (C) of RGD-EV:siPDL1; scale bar, 200 nm. (D-E) Mice-bearing GL261 tumors primed with 5-Gy RT were injected with Cy5.5-labeled EVs or RGD-EV:siPDL1 and the level of Cy5.5 was analyzed in the brain 24 h later. Representative NIRF images of brains (D) and quantification of fluorescence intensity in the tumor region (E) are shown. Data presented as mean ± SEM (n = 4); ***P < 0.001 by student’s t-test. (F,G) GBM-bearing mice were primed with RT and i.v. injected with PBS, targeted or nontargeted EVs carrying siCtrl or siPDL1. 48 h later, PD-L1 expression on GBM cells and TAMCs was analyzed by flow cytometry, as determined by the percentage of PD-L1+ population (F) and PD-L1 MFI (G). Data presented as mean ± SEM (n = 6); **P < 0.01, ****P < 0.0001 by One-way ANOVA.