Dados do Resumo

Título

Modulation of epigenetic targets as a strategy for enhancing the antitumor response of T lymphocytes

Introdução

T lymphocytes play a crucial role in immune surveillance, identifying and responding to threats, including tumor cells. Cytotoxic T lymphocytes (CD8+) recognize and eliminate tumor cells through the secretion of inflammatory mediators and cytotoxic molecules, while helper T lymphocytes (CD4+) support and enhance this process by secreting cytokines that stimulate and regulate the immune response. However, the continuous exposure to tumor antigens can lead to the exhaustion of these cells. The progressive loss of T cell function due to chronic antigenic stimulation, leading to a state with no possibility of returning cellular functionality, is a critical issue in adoptive cell therapy applied to cancer treatment, such as the use of T cells from the tumor microenvironment (TIL therapy), as well as in genetically modified CAR-expressing T cells (CAR-T). In line with this, interventions in the epigenome are strategies that may enhance the functional characteristics and antitumor activity of T lymphocytes, reducing the limitations of their use in the context of adoptive cell therapy.

Objetivo

The aim of this study is to evaluate the modulatory impact of epigenetic inhibition on the phenotype and functionality of human T cells, specially TIL and CAR-T cells, in order to explore the potential of identified epigenetic targets in enhancing these therapeutic approaches.

Métodos

First, we performed screening experiments to evaluate the effect of different epigenetic inhibitors on T lymphocytes from healthy donors. T lymphocytes were purified by cell sorting, cultured and activated with DynaBeads anti-CD3/CD28, IFN-γ and IL-2 and treated with the inhibitors. After culture, cells were analyzed by flow cytometry. Next, we tested the effect of Extra-Terminal Bromodomain (BET) inhibition using the inhibitor JQ1 on TIL from clear cell Renal Carcinoma (ccRCC) patients. T cells from tumor tissues were isolated and stimulated as described above, treated or not with JQ1, and analyzed by flow cytometry after 24 hours of culture. This study was approved by the Institutional Ethics Committee (2710/19 and 3223/22).

Resultados

JQ1 presented the most potent modulatory effect in T cells from healthy donnors, leading to increased expression of the activation marker CD69, accompanied by the reduction in expression of inhibitory receptors such as PD-1, CD39, TIM-3, LAG-3, and CTLA-4. JQ1 was also efficient in reducing exhaustion markers expression in TIL from ccRCC patients. Furthermore, after BET inhibition, CD4 TIL exhibited a less differentiated central memory phenotype (Tcm), accompanied by a reduction in the frequency of terminally differentiated memory cells (Temra). Experiments are being planned to evaluate the impact of this modulation on the antitumor response of CAR-T reated with an epigenetic inhibitor.

Conclusões

In light of this, our results show BET inhibition using JQ1 likely orchestrates epigenetic reprogramming that leads to reduced expression of exhaustion markers in T lymphocytes. Our results present the opportunity to explore the use of this inhibitor in cancer treatment, either alone or in combination with immune checkpoint blockers, specially in the context of adoptive cell therapy.

Financiador do resumo

CAPES, FAPESP, CNPq

Palavras Chave

T Lymphocytes; Epigenetic Modulation; Adoptive Cell Therapy