Activation of the cGAS-STING pathway combined with CRISPR-Cas9 gene editing triggering long-term immunotherapy

Abstract

Effective activation of cGAS-STING pathway combined with immune checkpoint blockade (ICB) within the immunosuppressive tumor microenvironment to induce stronger immune responsiveness yet remains challenging. CRISPR-Cas9 gene editing technology, which offers the benefits of permanence and irreversibility, could recognize the target genome sequence with sgRNA (Guide RNA) and guide the Cas9 protease to knock down the target gene. Herein, a nanoplatform (HMnMPH) for dual activation of cGAS-STING pathway in combination with CRISPR-Cas9 gene editing to silence programmed death ligand 1 (PD-L1) to trigger long-term immunotherapy was reported. The HMnMPH consists of hollow manganese dioxide (HMn) loaded with STING agonist (MSA-2) and CRISPR-Cas9/sg-PD-L1 plasmid with further modification of hyaluronic acid (HA). In acidic and GSH overexpressed tumor environment, HMnPMH was degraded to release large amounts of Mn ions and STING agonists, strongly and persistently activating the cGAS-STING pathway to promote the release of type I interferon and pro-inflammatory factors. Meanwhile, the released CRISPR-Cas9 plasmid could knockdown the PD-L1 immune checkpoint and restart immunosuppressive T cells to differentiate into cytotoxic T lymphocytes significantly, which reduced the activity of primary and distal tumors and demonstrated a long-term immune memory effect on distal tumors.

Keywords: CRISPR-Cas 9; Immunotherapy; PD-L1; cGAS-STING.