Rationally designed anti-autophagy nanosystems for reversing the immunosuppressive network in the tumor environment

Area of Science:

• Oncology
• Immunology
• Nanotechnology
• Drug Delivery

Background:

• Pancreatic ductal adenocarcinoma (PDAC) is characterized by an immunosuppressive tumor microenvironment (TME).
• Reversing this immunosuppression is crucial for effective cancer immunotherapy.
• Current treatments often struggle to overcome the TME's resistance.

Purpose of the Study:

• To engineer a pH-responsive nanosystem (CQCP) for co-delivery of an autophagy inhibitor (chloroquine) and a STING agonist (cyclic diguanylate).
• To evaluate the efficacy of CQCP in reversing PDAC immunosuppression and enhancing antitumor immunity.
• To assess the impact of CQCP on antigen presentation, immune cell activation, and overall survival in preclinical models.

Main Methods:

• Development of the CQCP nanosystem using pH-responsive polymer PC7A.
• In vitro and in vivo assessments of autophagy inhibition, MHC-I expression, and dendritic cell activation.
• Quantification of tumor-infiltrating lymphocytes (CD8+ T cells) and systemic immune responses.
• Evaluation of survival rates in PDAC-bearing mice treated with CQCP.

Main Results:

• CQCP significantly enhanced MHC-I expression on PDAC cells (2.1-fold increase).
• Activated dendritic cells (CD86+/CD40+) increased by 3.5-fold in the TME.
• Tumor-infiltrating CD8+ T cells increased by 42.6%, with observed systemic immune activation.
• CQCP achieved an 86% survival rate in tumor-bearing mice, outperforming monotherapies.

Conclusions:

• The CQCP nanosystem synergistically reverses PDAC immunosuppression by restoring antigen presentation and activating innate immunity.
• This dual-targeted nano-immunotherapy demonstrates robust antitumor efficacy.
• CQCP represents a promising therapeutic strategy for pancreatic ductal adenocarcinoma.