Dual drugs decorated bacteria irradiate deep hypoxic tumor and arouse strong immune responses

Intratumoral environment as a hypoxic, non-inflamed cold state is difficult for many agents to accumulate and activate the immune system. Intrinsically, facultative anaerobic Salmonella VNP20009 target the tumor hypoxic areas, invade into tumor cells and exhibit an immune effect. Here we engineer the bacteria by decorating their surface with newly synthesized heptamethine cyanine dyes NHS-N782 and JQ-1 derivatives to obtain the biohybrid agent N-V-J, leading to the deep tumor targeted photothermal therapy and magnified immunotherapy. Due to the mitochondrial targeting capacity of NHS-N782, N-V-J becomes susceptive to the temperature rise when reaching tumors. This synergistic strategy promotes the systemic immunity by creating an inflamed hot tumor state from three different dimensions, which include the inherent immunogenicity of bacteria, the near infrared laser triggered tumor antigens and the downregulation of PD-L1 expression. All these approaches result in effective and long-lasting T cell immune responses to prevent local and distant tumors for extended time. Leveraging the attenuated bacteria to transport dual drugs to the tumor tissues for self-synthetic vaccines provides a novel paradigm to enhance the bacteria-mediated cancer immunotherapy.

Automated summary

This study demonstrates the successful use of engineered Salmonella bacteria with modified surface to achieve targeted photothermal therapy and magnified immunotherapy in tumor tissues. The synergistic strategy stimulates the immune system from multiple dimensions, leading to effective prevention and inhibition of tumor growth.