Novel Survivin-Targeted Small Interfering RNA Delivered by Nanoparticles

The aim of the present study was to investigate the antitumor effect of our novel survivin-targeted small interfering RNA (siRNA) nanoliposomes on xenograft mouse models with human cervical carcinoma HeLa cells, and to evaluate pharmacokinetics.

siRNA nanoliposome was prepared and transfected into xenograft mouse models. Tumor growth in mice was determined and survivin expression was analyzed by using histologic and immunohischemical staining. Furthermore, low, moderate and high doses of survivin siRNA nanoliposomes were injected in 3 groups, and plasma concentrations were detected at various time points by reverse transcription quantitative polymerase chain reaction. Biodistribution of siRNA in tumor and other important organs were also determined.

Survivin expression was significantly downregulated by survivin siRNA delivery mediated by nanoliposome, along with significant suppression of cell growth. Peak concentrations were obtained at 15 minutes after injection in each group, with 1,042,538.00, 6,837,099.54 and 14,631,333.15pg/mL, respectively, and the plasma concentration decreased significantly after 24 hours. The half-time life of survivin siRNA nanoliposomes in each group was 3.60, 2.64 and 2.80 hours, respectively. The area under curve values were 952,190.88, 6,800,687.79 and 13,803,680.96h/pg/mL, and the total drug clearance were 1,050.12, 441.13 and 434.67mL/h/kg. A significant accumulation of Cy5-labeled siRNA was found in the tumor, and a nonspecific accumulation was reduced significantly in lung.

Our findings revealed that survivin suppression by siRNA may contribute to tumor inhibition through both proliferation inhibition and apoptosis promotion effect, and the pharmacokinetic characteristics serve as a fundamental role for further studies on its applicability for cancer therapy.