Tumor-selective lipopolyplex encapsulated small active RNA hampers colorectal cancer growth in vitro and in orthotopic murine.

Small active RNA (saRNA)-induced gene activation (RNAa) is a novel strategy to treat cancer. Our previous work proved that the p21-saRNA-322 successfully hindered colorectal cancer growth by activating p21 gene. However, the barrier for successful saRNA therapy is lack of efficient drug delivery. In the present study, a rectal delivery system entitled p21-saRNA-322 encapsulated tumor-selective lipopolyplex (TSLPP-p21-saRNA-322) which consist of PEI/p21-saRNA-322 polyplex core and hyaluronan (HA) modulated lipid shell was developed to treat colorectal cancer. Our results showed that this system maintained at the rectum for more than 6 h and preferentially accumulated at tumor site. CD44 knock down experiment instructed that the superb cellular uptake of TSLPP-p21-saRNA-322 attributed to HA-CD44 recognition. An orthotopic model of bio-luminescence human colorectal cancer in mice was developed using microsurgery and TSLPP-p21-saRNA-322 demonstrated a superior antitumor efficacy in vitro and in vivo. Our results provide preclinical proof-of-concept for a novel method to treat colorectal cancer by rectal administration of TSLPP formulated p21-saRNA-322.