Further evaluation of a novel nano-scale gene vector for in vivo transfection of siRNA

In this research, a lipid‐cationic polymer (LCP) containing the side‐chain branching of brassidic acid was synthesized using chemical methods. As a gene vector for small interfering ribonucleic acid (siRNA) transfection, the efficiency and biosafety of LCP were preliminarily evaluated to investigate its possible application on tumor gene therapy. The toxicity, side‐effects, and biosafety of LCP were investigated in animals based on the results of in vitro experiments. The siRNA against cyclooxygenase‐2 (COX‐2) was transfected by LCP to interfere with the COX‐2 expression in nude‐transplanted tumors. Hematoxylin and eosin stains, immunohistochemistry, reverse transcription‐polymerase chain reaction, and Western blot were performed to evaluate the efficiency of LCP for siRNA transfection. The animal toxicity experiment showed that a high concentration of LCP had a low toxic effect on animals and did not induce allergic or pyrogenic reactions. The results from the in vivo transfection indicated that LCP could efficiently transfect siRNA and silence the target gene expression. The LCP gene vector for siRNA transfection is highly efficient during in vivo transfection and had low toxicity. From all aspects of tumor gene therapy and basic research, LCP is valuable for scientific research and medical applications. J. Cell. Biochem. 112: 1329–1336, 2011. © 2011 Wiley‐Liss, Inc.