Engineering manganese-based immune amplifier for chemoimmunotherapy of peritoneal metastatic colorectal cancer.

Current immunotherapies exhibit limited clinical efficacy in patients with colorectal cancer (CRC). While manganese ions (Mn) can activate the cGAS-STING pathway to potentiate innate immunity, their clinical application is limited by poor tumor accumulation and potential systemic toxicity. Alendronate (ALN), an FDA-approved agent, exerts T cell immunomodulatory activity but is hampered by low bioavailability and undesired bone targeting. To effectively potentiate antitumor immunity against CRC, we developed a manganese-alendronate (MnALN) nanomedicine via infinite coordination, leveraging Mn and ALN to synergistically eliminate tumor cells. In addition, Mn triggers reactive oxygen species (ROS)-mediated endoplasmic reticulum (ER) stress and subsequent immunogenic cell death (ICD) in tumor cells, while its combination with ALN further enhances T cell immune responses, ultimately achieving efficient tumor growth inhibition and intense anti-tumor immune response. This study presented a dual-functional MnALN nanomedicine synthesized from clinically available Mn and ALN, simultaneously activating apoptosis and inflammation-related pathways in CRC cells, which provides an effective strategy for immune tolerance CRC therapy.