Oral siRNA delivery using dual transporting systems to efficiently treat colorectal liver metastasis

Oral siRNA delivery is an ideal way to translate siRNA therapeutic effects in the clinic due to its ability to be administered in convenient and multiple dosages. However, an effective oral delivery system requires overcoming both a hostile gastrointestinal (GI) environment and non-specific targeting. Here, an HTsRP-NC system is a new oral siRNA delivery system consisting of a siRNA/protamine (sRP) nano-complex protected by a multi-functional hyaluronic acid-taurocholic acid (HA-TCA) conjugate. The HTsRP-NC promotes cell penetration and enhances endosomal escape in cancer cells. Moreover, protection of the sRP by HA-TCA from the hostile GI environment helps the AKT siRNA complex to reach the liver through the utilization of a TCA-mediated enterohepatic bile acid recycling system. AKT siRNA was released by 90% in presence of hyaluronidase in the tumor cells which indicate the potential use of HTsRP-NCs for siRNA delivery to treat tumor. After HA receptor (CD44)-mediated cellular uptake of the HTsRP-NC by the liver cancer cells, functional expression of AKT siRNA leads to the suppression of metastatic liver cancer growth in a colorectal liver metastasis (CLM) murine model. Tumor nodules were reduced by more than 1 mm size compared to control group and tumor cells were suppressed by 50% after HTsRP-NCs treatment with AKT siRNA. Overall, oral administration of the HTsRP-NC supports its potential in therapeutic applications for the effective treatment of CLM.