A transcriptomic approach to understand the role of tumor-infiltrating CD39+ CD4+ FOXP3neg T cells.

BOSSIO, SABRINA N.; ABRATE, CAROLINA; CONSTANZA RODRIGUEZ; BOARI, JIMENA TOSELLO; PIAGGIO, ELIANE; ELMER FERNÁNDEZ; GRUPPI, ADRIANA; RODRÍGUEZ, EVA V. ACOSTA; MONTES, CAROLINA L.

Congreso; Reunión Anual de Sociedades de Biociencias. SAIC - SAI - SAFIS; 2020

The accumulation of tumor-infiltrating (TI) CD8+ T cells plays a pivotal role in the immune response against tumors. However, the function of CD4+ T cells within Tumor microenvironment (TME) remains uncertain. We previously demonstrated that tumors from tumor-bearing mice showed an important infiltrate of FOXP3neg CD4+ cells (Tconv) expressing CD39. CD39 is an ecto-enzyme involved in the conversion of eATP to immunomodulatory adenosine. We aim to determine the transcriptional profile of TI-CD39+Tconv cells. FOXP3-GFP mice (N=3), were injected with B16F10-OVA cancer cells. On day 17 the following TI-CD4+T cells were isolated by FACS: CD39+Tconv, CD39-Tconv and Treg. Then, we perform the transcriptome sequencing by RNAseq. Principal component analysis showed that all populations analyzed clustered separately, reflecting their differential transcriptional profile. To define the molecular profile of CD39+Tconv cells, we searched for differentially expressed genes (DEGs). We found 449 and 153 significantly up and down-regulated DEGs (p.adj<0.05, fold change=2), respectively, in CD39+Tconv compared to CD39-Tconv cells. Gene-encoding products related with cytotoxicity such as Gzmb, Gzmf, Gzmc, Prf1, Lyz2 and Eomes were up-regulated in CD39+Tconv. Moreover, Gene Ontology Enrichment Analysis revealed an increased expression of genes related to the following pathways: cytolysis, granzyme-mediated apoptotic signaling, lymphocyte chemotaxis and regulation of NK cell mediated cytotoxicity, among others (FDR<0.05). Comparison of CD39+Tconv to Treg identified 244 DEGs up-regulated in CD39+Tconv. Siglech, Gzme, Gzmf, Crtam and Cd160 were found to be among the most increased genes. In addition, we observed that CD39+Tconv were enriched in pathways associated with monocyte chemotaxis as well as cell-matrix adhesion and cell killing (FDR<0.05). Altogether, this data suggests that in TME CD39+Tconv cells could acquire a transcriptional program associated with cytotoxic CD4+ T cells.