Autologous tumoral esterase-driven therapeutic polymers sequentially orchestrated antigen-induction, STING activation and anti-angiogenesis for systemic cancer immune therapy.

Effective cancer immune therapy requires the orchestration of antigen induction, presentation and T-cell activation, further enhanced by anti-angiogenesis treatment; therefore, multiple therapeutics are generally used for such combination therapy. Herein, we report esterase-hydrolysable cationic polymers, N-[3-((4-acetoxy benzyl) oxy)-3-oxopropyl]-N-methyl-quaternized PEI (ERP) and poly{N-[2-(acryloyl-oxy) ethyl]-N-[p-acetyloxyphenyl]-N,N-dimethylammonium chloride} (PQDMA), capable of simultaneously inducing tumor cell immunogenic cell death (ICD) to release antigens, activating the cGAS-STING pathways of tumor macrophages and dendritic cells, and releasing antiangiogenic agent p-hydroxybenzyl alcohol (HBA). Thus, intratumoral injection of ERP or PQDMA systemically boosted the anti-cancer immunities and inhibited tumor angiogenesis in mouse hepatocellular carcinoma and melanoma bilateral tumor models, leading to more effective tumor growth inhibition of both treated and abscopal untreated tumors than ICD alone induced by mitoxantrone and control cationic polymers. Further study using gene knockout mice and transcriptome sequencing analysis confirmed the involvement of cGAS-STING and type I IFN signaling pathways. This work demonstrates ERP and PQDMA as the first examples of inherent therapeutic polymers, accomplishing systemic tumor inhibition without combining other therapeutic agents.