Ultrasound-driven plant lipid vesicles amplify oncolytic virotherapy in colorectal cancer.

Abstract

Colorectal cancer (CRC) remains a highly aggressive malignancy, and its treatment with oncolytic virotherapy is hindered by multiple delivery barriers and delayed therapeutic kinetics. To address these challenges, we developed a plant lipid-based vesicular system (P-M@Ce6-OVs) co-encapsulating oncolytic viruses (OVs) and sonosensitizer chlorin e6 (Ce6), enabling ultrasound (US)-guided, spatiotemporally controlled delivery to deep colorectal tumors. Under US exposure, the system enhanced mucus infiltration, tumor penetration, and lysosomal escape, while activating sonodynamic therapy to rapidly induce tumor ablation and compensate delayed viral oncolysis. In CRC mouse models, rectal administration of P-M@Ce6-OVs with US exposure achieved a 10.3-fold reduction in tumor burden compared with the control (without treatment), markedly outperforming monotherapies. Importantly, combination with αPD-L1 not only suppressed primary CRC and re-challenged tumors mimicking metastatic relapse, but also induced durable systemic immune protection. This triple combination further potentiated systemic and mucosal antitumor immunity, restoring cytotoxic T-cell function and reinforcing humoral and gut-localized immune responses. Notably, this treatment reshaped gut microbiota by enriching nucleoside-metabolizing bacteria (e.g., Lactobacillus taiwanensis) and altering microbial metabolic profiles, including the pathways related to pyrimidine catabolism and arachidonic acid oxidation. These microbiota and metabolic changes were associated with immune remodeling and tumor suppression. Collectively, this platform integrated US-enabled delivery, sonodynamic activation, and microbiome remodeling to synergistically suppress CRC and re-challenged tumor progression, amplifying virotherapy and antitumor immunity.