Guadecitabine increases response to combined anti-CTLA-4 and anti-PD-1 treatment in mouse melanoma in vivo by controlling the responses of T-cells, myeloid derived suppressor cells and NK cells

ABSTRACT: The combination of PD-1 and CTLA-4 blockade has determined an improved overall survival (OS) rate for malignant melanoma at 3 years of 58% as compared to ipilimumab alone. Immune checkpoint blockers (ICB) limit the tumor’s immune escape yet only for approximately a third of all tumors and, in most cases, for a limited amount of time. Several approaches to overcome resistance to ICB are being investigated among which the addition of epigenetic drugs that are expected to act on both immune and tumor cells. Guadecitabine, a dinucleotide prodrug of a decitabine linked via phosphodiester bond to a guanosine, showed promising results in the phase-1 clinical trial, NIBIT-M4 (NCT02608437). We used the syngeneic B16F10 murine melanoma model to study the effects of immune checkpoint blocking antibodies against CTLA-4 and PD-1 in combination, with and without the addition of Guadecitabine. We comprehensively characterized the tumor’s and the host’s responses under different treatments by flow cytometry, immunohistochemistry (MANTRA), gene methylation and scRNA sequencing. Guadecitabine in combination with ICBs significantly reduced tumor growth compared to ICB and Guadecitabine treatment. The demethylating drug led to a general DNA-demethylation and transcriptional modification of gene expression. In particular, Guadecitabine greatly enhanced the efficacy of combined ICBs by increasing effector memory CD8+ T cells, inducing effector NK cells in the spleen and reducing tumor infiltrating regulatory T cells and MDSC cells, in the TME. These results indicate Guadecitabine as a promising epigenetic drug to be added to ICB therapy.

ORGANISM(S): Mus musculus

PROVIDER: GSE220698 | GEO | 2023/04/25

REPOSITORIES: GEO