Dados do Resumo

Título

Boosting antitumor activity of NK cells from triple-negative breast cancer patients through epigenetic modulation

Introdução

Breast cancer (BC) is the most diagnosed cancer in women. About 20% of BC are of the triple-negative (TNBC) type, which has the worst prognosis and the highest intratumoral infiltration. NK cells are key cells in antitumor response infiltrating the tumor microenvironment (TME), through the secretion of inflammatory and cytotoxic mediators. However, these cells become dysfunctional due to the suppressive features of TME. Immune checkpoint inhibitors can restore their functional activity, but they are not fully efficient. In light of this, epigenetic inhibitors can be an option to rescue the antitumor function of NK cells improving the treatment tools for refractory patients.

Objetivo

The aim of this study is to evaluate the effect of CBP/p300 inhibitor (A-485) on the antitumor function of NK cells from patients with TNBC.

Métodos

First, to set up the experimental conditions, we conducted in vitro experiments using NK cells from healthy donors (HD). Peripheral blood mononucleated cells (PBMC) were obtained by Ficoll gradient and NK cells were isolated by negative selection using magnetic beads. Purified NK cells were stimulated in vitro with IL-15. To evaluate the effects of CBP/p300 inhibition, the A-485 inhibitor was added to the cultures on day 0. After 4 days, cells were treated with a cytokine cocktail (IL-12, IL-15, and IL-18), challenged with the K562 tumor cell line, and analyzed by flow cytometry. The use of healthy donor samples was approved by our Institutional Ethics Comitee (2710/19). Next, to analyze the effect of A-485 in NK cells from TNBC patients, peripheral and intratumoral NK cells, obtained from blood and tumor tissue samples, will be stimulated in the presence or absence of A-485 as described above, followed by flow cytometry analysis. Furthermore, tumor tissue will be orthotopically injected into female mice followed by A-485-treated NK cells to test their antitumoral effects. The use of samples from TNBC patients and the experimental procedures in animal models are under submission in the respective Institutional Ethics Comitee.

Resultados

We conduct an in vitro experiment in which NK cells from one HD were stimulated in the presence or absence of the A-485 and observed that NK cells had high viability under both circumstances, which indicates that the CBP/p300 inhibitor does not cause cell toxicity in the concentration used. Besides, after CBP/p300 inhibition, the number of total NK cells remained unchanged. Furthermore, we found that A-485-treated NK cells presented increased co-expression of IFN-γ and TNF-α or Granzyme and CD107A, a degranulation marker, indicating heightened functional state. Although these promising results, a larger sample size is required before any conclusions can be drawn.

Conclusões

Our initial findings suggest that CBP/p300 inhibition can impact the phenotype and function of NK cells, increasing the expression of cytotoxic and inflammatory mediators and could be a potential strategy to enhance NK cell function in the TME of TNBC patients.

Financiador do resumo

CAPES; CNPq; FAPESP

Palavras Chave

NK cells; Breast cancer; Epigenetic inhibitors