Target specific intracellular delivery of siRNA/PEI-HA complex by receptor mediated endocytosis.

Hyaluronic acid (HA) plays important biological roles in tissue integrity, angiogenesis, wound healing, and cell motility through the interaction with receptors on cell membranes. In this work, we investigated the effect of HA modification on the receptor-mediated endocytosis labeling HA derivatives with quantum dots (QDots). HA-QDot conjugates with a degree of modification less than ca. 25 mol % appeared to be more efficiently taken up to B16F1 cells by HA receptor mediated endocytosis than QDots alone. On the basis of bioimaging study, polyethyleneimine, PEI-HA conjugate with 24.2 mol % PEI content was developed as a target specific intracellular delivery carrier of siRNA. The siRNA/PEI-HA complex exhibited higher gene silencing efficiency in B16F1 cells with HA receptors than siRNA/PEI complex. Anti-PGL3-Luc siRNA/PEI-HA complex appeared to silence PGL3-Luc gene in the range of 50%-85% depending on the serum concentration up to 50 vol %. According to in vivo biodistribution test, siRNA/PEI-HA complex accumulated mainly in the tissues with HA receptors such as liver, kidney, and tumor. Furthermore, intratumoral injection of anti-VEGF siRNA/PEI-HA complex resulted in an effective inhibition of tumor growth by the HA receptor mediated endocytosis to tumor cells in C57BL/6 mice. Considering all these results, anti-VEGF siRNA/PEI-HA complex was thought to be applied successfully as target specific antiangiogenic therapeutics for the treatment of diseases in the tissues with HA receptors, such as liver cancer and kidney cancer.