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High-dose ascorbic acid synergizes with anti-PD1 in a lymphoma mouse model

ABSTRACT: Major efforts are underway to identify agents that can potentiate effects of immune checkpoint inhibition. Here, we show that ascorbic acid (AA) treatment caused genome wide demethylation and enhanced expression of endogenous retroviral elements in lymphoma cells. AA also increased 5-hydroxymethylcytosine (5hmC) levels of CD8+ T cells and enhanced their cytotoxic activity in a lymphoma co-culture system. High-dose AA treatment synergized with anti-PD1 therapy in a syngeneic lymphoma mouse model, resulting in marked inhibition of tumor growth compared with either agent alone. Analysis of the intra-tumoral epigenome revealed increased 5hmC with AA treatment, consistent with in vitro findings. Analysis of the tumor immune microenvironment revealed that AA strikingly increased intra-tumoral infiltration of CD8+ T cells and macrophages, suggesting enhanced tumor immune recognition. The combination treatment markedly enhanced intra-tumoral infiltration of macrophages and CD8+ T lymphocytes, granzyme B production by cytotoxic cells (cytotoxic T cells and Natural Killer cells), and IL-12 production by antigen presenting cells compared with single agent anti-PD1. These data indicate that AA potentiates anti-PD1 checkpoint inhibition through synergistic mechanisms. The study provides compelling rationale for testing combinations of AA and anti-PD1 agents in lymphoma patients as well as in pre-clinical models of other malignancies.

ORGANISM(S): Homo sapiens

PROVIDER: GSE141397 | GEO | 2020/01/27

REPOSITORIES: GEO

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High-dose ascorbic acid synergizes with anti-PD1 in a lymphoma mouse model

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