Multifunctional armored nanoemulsion of elemene combining ferroptosis induction and gut homeostasis restoration in colorectal cancer therapy.

UNLABELLED: Cancer remains a leading cause of death worldwide. Colorectal cancer (CRC) is the most common type of gastrointestinal malignancy, with the combined effect of multiple etiological factors. Multifunctional nanocomposites present a promising platform for synergistic therapy of CRC. Elemene (EL), an active component in traditional Chinese medicine, exhibits both antitumor and immunostimulatory activities. However, its clinical application is limited by poor stability, low tumor accumulation, and the difficulty of effectively harnessing its dual activities. Herein, we developed an orally administered, colon-targeted nanoemulsion, LMP@EL-CNE, comprising EL cationic nanoemulsions (EL-CNE) armored with a low-methoxyl pectin (LMP) polysaccharide shell. This system exhibits dual responsiveness to colonic microflora enzymes and pH, allowing for prolonged retention and targeted drug release in the colon. Subsequently, it generates ultra-small EL nanodroplets (∼20 nm), which enhance tumor penetration and accumulation. Notably, LMP@EL-CNE induces mitochondrial dysfunction and downregulates glutathione peroxidase 4 (GPX4), a key regulator of ferroptosis. This disruption of the balance unlocks a more potent ferroptosis response, amplifying EL's intrinsic activity in CT26 cells. In an in vivo orthotopic CRC model, LMP@EL-CNE exhibited potent anti-tumor activity and activated anti-tumor immunity, manifesting as a "hot" tumor microenvironment, outperforming the EL commercial preparation. Furthermore, this polysaccharide-armored nanoemulsion has been proven to restore gut homeostasis by repairing damaged epithelial barriers and reshaping the gut microbiota. In conclusion, we propose a novel nano-platform that integrates multiple functions to induce ferroptosis, activate anti-tumor immunity, and restore gut homeostasis, providing a comprehensive and effective strategy for colorectal cancer treatment.

CHEMICAL COMPOUNDS STUDIED IN THIS ARTICLE: Elemene (EL CAS No. 33880-83-0) the primary active pharmaceutical ingredient (API) with antitumor activity Polyoxyethylene hydrogenated castor oil (RH40, CAS No. 61788-85-0), a key non-ionic surfactant for nanoemulsion stabilization.Hexadecyl trimethyl ammonium bromide (CTAB, CAS No. 57-09-0), a cationic surfactant used in the nanoemulsion formulation.Low-methoxyl pectin (LMP, CAS No. 9000-69-5), an anionic polysaccharide constituting the functional "armor" of the nanoemulsion.Liproxstatin-1 (Lip-1, CAS No. 950455-15-9), a potent ferroptosis inhibitor used for mechanistic validation.Glutathione (GSH, reduced form, CAS No. 70-18-8), a central antioxidant, quantified to assess the status of the GPX4-mediated ferroptosis defense system.Malondialdehyde (MDA, CAS No. 542-78-9), the primary end-product of lipid peroxidation, quantified as a key indicator of ferroptosis.