Targeted therapeutic effects of oral inulin-modified double-layered nanoparticles containing chemotherapeutics on orthotopic colon cancer

Colon cancer is emerging as one of the most prevalent cancers globally. Oral colonic drug delivery systems have attracted considerable attention in the treatment of orthotopic colon cancer due to their superior properties. However, the particularity and complexity of the gastrointestinal structure are a hindrance to the safe delivery of drugs to the target site of the colon tumor. Herein, to achieve an effective delivery system specifically targeting the colon, we designed paclitaxel (PTX)-loaded oral colon double-targeted nanoparticles using polylactic acid-polyethyleneimine (PLA-PEI) and hyaluronic acid-inulin (HA-IN). IN is enzyme sensitive and hardly degraded in the upper digestive tract; as such, it can ensure the safe delivery of nanoparticles to the colon. The "IN shell" is degraded by colon-specific bacteria at the colon site. The exposed HA not only promotes intestinal mucosal crossing of nanoparticles, but also acts as the target of CD44 and plays an active targeting role in tumor tissues. The action of the proton sponge effect of PEI induces the successful release of the nanoparticle. The prepared nanoparticles have a negative charge of -19.5 ± 1.2 mV and a size of 176.7 ± 0.3 nm with a narrow PDI of 0.148 ± 0.004. C26 cells were used for in vitro anticancer studies, including fluorescence staining and flow cytometry, and to explore inhibition of proliferation. The analysis demonstrated that the nanoparticles were more efficiently taken up by cancer cells, exhibiting greater cytotoxicity and apoptosis-inducing ability compared to free drugs. Moreover, in vivo studies revealed that the nanoparticles could remain in vivo for 24 h and accumulate at the tumor site. These data provide evidence of the therapeutic effect on orthotopic colon cancer. Also, safety evaluation results demonstrated that PLA-PEI/HA-IN is a safe drug delivery vector, therefore, holds great promise as a new therapeutic strategy for orthotopic colon cancer treatment.