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

Objective: 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 naive T lymphocytes to adipose-derived MSCs (ASCs). Materials and Methods: 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 naive CD4+ T cells from peripheral blood of five healthy donors. Naive 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-beta) and IL-17 were assessed using flow cytometry and ELISPOT assays, respectively. Results: 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-beta 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-beta of cancer-ASCs (P<0.05). Conclusion: 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.