Extracellular Vesicle Based Therapeutic Targeting of Beta-Catenin to Modulate Anti-Cancer Immune Responses in Hepatocellular Cancer

Abstract

Background: Hepatocellular carcinoma (HCC) is a leading cause of cancer related death worldwide. Although HCC can respond to immune checkpoint inhibitors such as monoclonal antibodies against PD-1, many patients fail to respond or develop secondary resistance. Activation of Wnt/β-catenin signaling can contribute to immune evasion. Mutations in β-catenin are amongst the most frequent mutations associated with HCC. Thus, our aim was to directly target β-catenin to enhance the therapeutic response to immune checkpoint inhibition. Methods: A synthetic transgenic mouse of experimental HCC induced by MET/ β-catenin expression, and extracellular vesicles as a therapeutic delivery agent were used to evaluate the efficacy of directly targeting β-catenin on response to anti-PD-1. Findings: These studies show that (1) oncogenic β-catenin could be therapeutically targeted using a biological nanoparticle based delivery approach, (2) targeting β-catenin using siRNA delivered within extracellular vesicles can reduce tumor growth, and (3) the therapeutic response to anti-PD-1 can be enhanced by concomitantly targeting β-catenin using therapeutic extracellular vesicles. These preclinical studies establish the efficacy of use of biological nanoparticles as an endogenous delivery vehicle for therapeutic RNA delivery and support the use of therapeutic strategies targeting tumor-intrinsic β-catenin as an adjunct to anti-PD-1 based therapy. Interpretation: Combination therapy with anti PD-1 and β-catenin siRNA delivered using biological nanoparticles provide an effective strategy for the treatment of HCC. This strategy could be further exploited into targeted approaches for immune potentiation by countering oncogenemediated resistance to immunotherapies. Funding Statement: Supported in part by the National Institutes of Health.TP is funded by NIH (UH3-TR000884). This publication is part of the NIH Extracellular RNA Communication Consortium paper package and was supported by the NIH Common Fund's exRNA Communication Program Declaration of Interests: There are no conflicts for any of the authors related to design, execution or analysis of the experiments presented in this manuscript. Ethics Approval Statement: All studies involving animals were performed in accordance with protocols approved by the Mayo Clinic Institutional Animal Care and Use committee.