Helios, CD73 and CD39 Induction in Regulatory T Cells Exposed to Adipose Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) have prominent immunomodulatory roles in the tumor microenvironment. The current study intended to elucidate Treg subsets and their cytokines after exposing naïve T lymphocytes to adiposederived MSCs (ASCs).

In this experimental study, to obtain ASCs, breast adipose tissues of a breast cancer patient and a normal individual were used. Magnetic cell sorting (MACS) was employed for purifying naïve CD4⁺ T cells from peripheral blood of five healthy donors. Naïve CD4⁺ T cells were then co-cultured with ASCs for five days. The phenotype of regulatory T cells (Tregs) and production of interleukine-10 (IL-10), transforming growth factor beta (TGF-β) and IL-17 were assessed using flow cytometry and ELISPOT assays, respectively.

CD4⁺CD25^-FOXP3⁺CD45RA⁺ Tregs were expanded in the presence of cancer ASCs but CD4⁺CD25⁺Foxp3⁺CD45RA⁺ regulatory T cells were up-regulated in the presence of both cancer- and normal-ASCs. This up-regulation was statistically significant in breast cancer-ASCs compared to the cells cultured without ASCs (P=0.002). CD4⁺CD25⁺ FOXP3⁺Helios⁺, CD4⁺CD25^- FOXP3⁺Helios⁺ and CD25⁺ FOXP3⁺CD73⁺CD39⁺ Tregs were expanded after co-culturing of T cells with both cancer-ASCs and normal-ASCs, while they were statistically significant only in the presence of cancer-ASCs (P<0.05). Production of IL-10, IL-17 and TGF-β by T cells was increased in the presence of either normal- or cancer-ASCs; however, significant effect was only observed in the IL-10 and TGF-β of cancer-ASCs (P<0.05).

The results further confirm the immunosuppressive impacts of ASCs on T lymphocytes and direct them to specific regulatory phenotypes which may support immune evasion and tumor growth.