Effective suppression of the Kirsten rat sarcoma viral oncogene in pancreatic tumor cells via targeted small interfering RNA delivery using nanoparticles.

Objectives: The objective of this study was to establish an efficient carrier for small interfering RNA (siRNA) delivery targeting pancreatic tumor cells.

Methods: A copolymer consisting of a single-chain variable fragment targeted to human CD44 variant 6 (scFv(CD44v6)) functional group conjugated to polyethylene glycol-poly-L-lysine was synthesized and assembled into micelles encapsulating the siRNAs. Flow cytometry and Western blot assays were performed to evaluate the transfection efficiency and gene-silencing effect of the siRNAs. Afterward, (4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, Transwell, soft agar colony formation, and enzyme-linked immunosorbent assays were performed to evaluate the biological functions of PANC-1 cells after Kirsten rat sarcoma viral oncogene knockdown. In vivo assays were performed using a BALB/c (nu/nu) mouse model subcutaneously injected with PANC-1 xenografts. Real-time in vivo fluorescence imaging was used to monitor the tumor homing of the nanoparticles.

Results: The scFv(CD44v6) enabled more efficient delivery of siRNAs and exhibited enhanced gene silencing compared with nontargeted nanoparticles. Furthermore, targeted delivery of the siRNAs induced a potent inhibitory effect on cell proliferation, colony formation, invasion, and vascular endothelial growth factor production. The animal assays revealed that single-chain variable fragment nanoparticles accumulated in the tumor tissue and enhanced the inhibition of tumor growth in vivo.

Conclusions: The scFv(CD44v6)-conjugated nanocarriers provide a highly efficient and safe platform for systemic gene therapy for pancreatic cancer.