Figure 3.

f(SLN)-iRGD specific targeting of glioblastoma cells. (a) Human U87 or mouse GL261 glioma cells were preincubated (or not) with free iRGD or scriRGD (20 μM for competitive binding) for 30 min and treated with 50 μg/mL of either f(SLN)-Cy5.5, f(SLN)-iRGD-Cy5.5, or f(SLN)-scriRGD-Cy5.5. Three hours post-treatment, cells were washed and analyzed by flow cytometry. Representative flow cytometry charts (left) and relative percentage of Cy5.5-positive cells as compared to untreated mock group (right) are shown, **P < 0.01 (n = 3). (b) Similar experimental setup to (a) but using siEGFR-complexed SLN. Twenty-four hours post-treatment, RNA was extracted and analyzed by qRT-PCR for EGFR mRNA (β-actin as housekeeping gene) (*P < 0.05, **P < 0.01, ***P < 0.001). (c) Mice bearing GL261 tumors were retro-orbital injected with f(SLN)-iRGD:siEGFR/PDL1 or PBS control on days 8, 9, and 11 post-tumor implantation. Twenty-four hours after the last injection, brain tumors were removed, RNA was extracted and analyzed for EGFR and PD-L1 mRNA levels by qRT-PCR. Data expressed as mean ± SD (*P < 0.05, n = 5).