Nanoparticle-Mediated In Situ Molecular Reprogramming of Immune Checkpoint Interactions for Cancer Immunotherapy

Abstract

Immune checkpoint blockade involves targeting immune regulatory molecules with antibodies. Preclinically, complex multiantibody regimes of both inhibitory and stimulatory targets are a promising candidate for the next generation of immunotherapy. However, in this setting, the antibody platform may be limited due to excessive toxicity caused by off target effects as a result of systemic administration. RNA can be used as an alternate to antibodies as it can both downregulate immunosuppressive checkpoints (siRNA) or induce expression of immunostimulatory checkpoints (mRNA). In this study, we demonstrate that the combination of both siRNA and mRNA in a single formulation can simultaneously knockdown and induce expression of immune checkpoint targets, thereby reprogramming the tumor microenvironment from immunosuppressive to immunostimulatory phenotype. To achieve this, RNA constructs were synthesized and formulated into stable nucleic acid lipid nanoparticles (SNALPs); the SNALPs produced were 140−150 nm in size with >80% loading efficiency. SNALPs could transfect macrophages and B16F10 cells in vitro resulting in 75% knockdown of inhibitory checkpoint (PDL1) expression and simultaneously express high levels of stimulatory checkpoint (OX40L) with minimal toxicity. Intratumoral treatment with the proposed formulation resulted in statistically reduced tumor growth, a greater density of CD4+ and CD8+ infiltrates in the tumor, and immune activation within tumor-draining lymph nodes. These data suggest that a single RNA-based formulation can successfully reprogram multiple immune checkpoint interactions on a cellular level. Such a candidate may be able to replace future immune checkpoint therapeutic regimes composed of both stimulatory-and inhibitory-receptor-targeting antibodies.

Tea Polyphenol Coordinated with Nanoparticles of ZIF-8 and Coated with Polydopamine and PEG for Immuno-Oncotherapy

“…Besides antibodies, other methods to inhibit the expression of PD-1 or PD-L1 have been studied, for instance, the small-molecule drugs, 47 NO 48 or siRNA. 49 We have previously found that EGCG, a natural molecule, could be used as a PD-L1 checkpoint inhibitor. 28 However, the bioavailability of EGCG limits its broad application.…”

“…The αPD-L1 or αPD-1 antibodies have been widely used in clinics; however, the therapeutic efficiency still needs to be further improved. Besides antibodies, other methods to inhibit the expression of PD-1 or PD-L1 have been studied, for instance, the small-molecule drugs, NO or siRNA . We have previously found that EGCG, a natural molecule, could be used as a PD-L1 checkpoint inhibitor .…”

Strategies targeting PD-L1 expression and associated opportunities for cancer combination therapy

“…Importantly, this immunotherapy process does not require the engagement of toxic T cells. Aiming at a more efficient way to reprogram TME, mRNA (mOX40L) and siRNA (siPDL1) were simultaneously formulated into a single nanoparticle by Al-Jamal and coworkers ( Figure 4 E ) 92 . siPDL1 can downregulate the expression of the coinhibitory PD-L1, while mOX40L can upregulate the expression of the costimulatory OX40L, the synergy of which leads to much improved tumor immunogenicity.…”

Materialistic Interfaces with Nucleic Acids: Principles and Their Impact

“…[ 193 ] Furthermore, NPs could in situ mediate the molecular reprogramming of immune checkpoint interactions and cancer immunotherapy was developed. [ 194 ]…”