RNAi-Mediated ?-Catenin Inhibition Promotes T Cell Infiltration and Antitumor Activity in Combination with Immune Checkpoint Blockade.
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ABSTRACT: Wnt/?-catenin signaling mediates cancer immune evasion and resistance to immune checkpoint therapy, in part by blocking cytokines that trigger immune cell recruitment. Inhibition of ?-catenin may be an effective strategy for increasing the low response rate to these effective medicines in numerous cancer populations. DCR-BCAT is a nanoparticle drug product containing a chemically optimized RNAi trigger targeting CTNNB1, the gene that encodes ?-catenin. In syngeneic mouse tumor models, ?-catenin inhibition with DCR-BCAT significantly increased T cell infiltration and potentiated the sensitivity of the tumors to checkpoint inhibition. The combination of DCR-BCAT and immunotherapy yielded significantly greater tumor growth inhibition (TGI) compared to monotherapy in B16F10 melanoma, 4T1 mammary carcinoma, Neuro2A neuroblastoma, and Renca renal adenocarcinoma. Response to the RNAi-containing combination therapy was not dependent on Wnt activation status of the tumor. Importantly, this drug combination was associated with elevated levels of biomarkers of T cell-mediated cytotoxicity. Finally, when CTLA-4 and PD-1 antibodies were combined with DCR-BCAT in MMTV-Wnt1 transgenic mice, a genetic model of spontaneous Wnt-driven tumors, complete regressions were achieved in the majority of treated subjects. These data support RNAi-mediated ?-catenin inhibition as an effective strategy to increase response rates to cancer immunotherapy.
SUBMITTER: Ganesh S
PROVIDER: S-EPMC6225018 | biostudies-literature | 2018 Nov
REPOSITORIES: biostudies-literature
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