Improved chemotherapy against breast cancer through immunotherapeutic activity of fucoidan decorated electrostatically assembled nanoparticles bearing doxorubicin.

Immunotherapeutic nanoparticles (NPs) could be a viable option for delivering cytotoxic agents in a manner which suppresses their toxic manifestations. Doxorubicin (DOX) loaded NPs were prepared using fucoidan (FCD), an immunomodulatory polysaccharide and evaluated against cancer. FCD was electrostatically assembled with cationic polyethylenimine (PEI) through intermolecular electrostatic interactions to develop an immunomodulatory platform to deliver DOX. FCD NPs offered improved cytotoxicity (2.64 folds), cell cycle arrest in G1-S phase (34.65%) and apoptosis (66.12%) in tumor cells compared to free DOX. The enhanced apoptosis was due to raised mitochondrial depolarization (88.00%). In vivo anticancer activity in 4T1 induced tumor bearing BALB/c mice demonstrated a 2.95 folds enhanced efficacy of NPs. Importantly, NPs treatment generated an immunotherapeutic response indicated by gradual increment of the plasma IL-12 levels and reversed polarization of tumor associated macrophages (TAMs) towards M1 subtype. Furthermore, pharmacokinetic study suggested that NPs administration in tumor infested mice caused serum DOX levels to vary in a biphasic pattern, with twin peaks occurring at 1 h and 6 h which help in maintaining preferential drug localization in tumor. Developed NPs would be an excellent approach for improved immune-chemotherapy (in terms of efficacy, safety and immunocompetency) against cancer.