Amphiphilic polymeric nanodrug integrated with superparamagnetic iron oxide nanoparticles for synergistic antibacterial and antitumor therapy of colorectal cancer.

Colorectal cancer (CRC) is one of the most prevalent and deadly malignancies that can be influenced by Fusobacterium nucleatum (Fn), a bacterium that promotes tumor development and chemoresistance, resulting in limited therapeutic efficacy. Traditional antibiotics cannot effectively eliminate Fn at tumor site due to issues like biofilm formation, while chemotherapy alone fails to suppress tumor progression. Therefore, the development of new methods to eliminate Fn and promote antitumor efficacy is of great significance for improving the outcome of CRC treatment. Herein, we developed a nanodrug (OPPL) that integrates oleic acid-modified superparamagnetic iron oxide nanoparticles (O-SPIONs) and an amphiphilic polymer (PPL) to deliver the platinum prodrug and antimicrobial lauric acid (LA) for enhancing the treatment of CRC. We demonstrated that OPPL can synergistically enhance antibacterial and biofilm disruption activities against Fn along with the antimicrobial LA by producing reactive oxygen species (ROS) through its peroxidase-like activity. Furthermore, the OPPL nanodrug can increase intracellular ROS, promote lipid peroxides and deplete glutathione, leading to ferroptosis. By combining chemotherapy and induced ferroptosis, the OPPL nanodrug exhibited high cytotoxicity against CRC cells. In vivo studies showed that the OPPL nanodrug could enhance tumor accumulation, enable magnetic resonance imaging, suppresse tumor growth, and inhibit growth of intratumor Fn. These results suggest that OPPL is an effective and promising candidate for the treatment of Fn-infected CRC. STATEMENT OF SIGNIFICANCE: The enrichment of Fusobacterium nucleatum (Fn) in colorectal cancer is reported to exacerbate tumor malignancy and is particularly responsible for chemoresistance. To this respect, we strategically elaborated multifaceted therapeutics, namely OPPL nanodrug, combining oleic acid-modified superparamagnetic iron oxide nanoparticles (O-SPIONs) with a polymer containing a platinum prodrug and antimicrobial lauric acid. The O-SPION components exert distinctive peroxidase-like activity, capable of stimulating Fenton reactions selectively in the tumor microenvironment, consequently accounting for the progressive production of reactive oxygen species. Hence, O-SPIONs have been demonstrated to not only supplement the antimicrobial activities of lauric acid in overcoming Fn-induced chemoresistance but also stimulate potent tumor ferroptosis. Our proposed dual antimicrobial and chemotherapeutic nanodrug provides an appreciable strategy for managing challenging Fn-infected colorectal cancer.