Metabolically hijacked Listeria monocytogenes synergizes STING activation and dual cell death for enhanced antitumor immunotherapy.

BACKGROUND: Listeria monocytogenes (LM) holds promise as a microbial vector for cancer immunotherapy, yet its clinical translation requires precise engineering to achieve an optimal balance between attenuation and immunogenicity. This study aimed to develop an engineered LM strain that induces metabolic reprogramming while enhancing antitumor efficacy through multimodal immune activation. RESULTS: We encapsulated cepharanthine nanoparticles (CEP NPs) into a double-gene attenuated LM strain via electroporation, resulting in the induction of metabolic reprogramming and the emergence of a 'zombie-like' phenotypic state (LM(e)@CEP). This modification disrupted folate metabolism to induce bacterial metabolic dormancy, while triggering a cyclic dinucleotide (CDN) surge that amplified STING-mediated immunogenicity. The CEP payload localized to tumors and exerted dual cytotoxic effects by simultaneously inducing ferroptosis and apoptosis in situ. These direct tumoricidal effects synergize with the immunostimulatory capacity of LM(e)@CEP, effectively modulating the tumor immune microenvironment and exerting robust antitumor effects. Preclinical validation across multiple murine tumor models and ex vivo human tumor specimens confirmed the therapeutic versatility of the platform. Furthermore, results in STING(-/-) mice corroborated that LM(e)@CEP's antitumor effectiveness partly depends on STING pathway activation, and its therapeutic potential may be further enhanced by PD-L1 blockade, thereby mitigating STING-driven immune suppression. CONCLUSIONS: These findings establish metabolic hijacking of bacterial vectors as a paradigm-shifting strategy that integrates direct tumor killing with multimodal immune activation, overcoming key barriers in microbial immunotherapy.