Fig. 4.

CH-CA-Spe nanogel enabled effective intratumor siRNA delivery and silencing of vascular endothelial growth factor (VEGF). Tumor-bearing mice were injected with FITC-siRNA alone, FITC-siRNA/cationic liposome complex and FITC-siRNA/nanogel complex into preestablished subcutaneous renal cell carcinoma (RCC) tumors (20 μg of siRNA/50 μL/tumor). Three (a) and twenty-four (b) hours later, the tumor tissue was observed under confocal laser scanning microscopy. Representative bright field (left), fluorescent (middle) and merged (right) images are shown. Scale bar, 100 μm. (c) Tumor-bearing mice were given an intratumoral injection with siRNA/nanogel complex (20 μg of siRNA/50 μL/tumor) or drug delivery system alone, as indicated. Twenty-four hours later, VEGF mRNA levels were measured by real-time RT-PCR. Data represent the means ± SD (n = 5–7).*P < 0.05 versus control non-silencing siRNA (siCont) or cationic liposome group.