Induction of T Regulatory Subsets from Naïve CD4+ T Cells after Exposure to Breast Cancer Adipose Derived Stem Cells

Background: Adipose derived stem cells (ASCs) provoke the accumulation and expansion of regulatory T cells, leading to the modulation of immune responses in tumor microenvironment. Objective: To assess the effect of tumoral ASCs on the trend of regulatory T cells differentiation. Methods: Peripheral blood naïve CD4+ T cells were co-cultured with ASCs derived from breast cancer or normal breast tissues. In separate cultures peripheral blood naïve CD4+ T cells were exposed to the culture supernatants of ASCs. Results: Generation of CD4+CD25+Foxp3+ and CD4+CD25- Foxp3+ Treg subsets was observed after coculture of naïve CD4+ T cell with either ASCs or the related supernatant. The percentage of CD4+CD25+Foxp3+ cells increased after exposing naïve CD4+ T cells to both ASCs and their supernatants while augmentation of CD4+CD25-Foxp3+ subset mostly depended on the presence of ASCs. Similarly, upregulation of FoxP3 molecule was more significant in condition of cell to cell contact. IL-4 and IL-10 were up-regulated in the cocultured naïve CD4+ T cells after exposure to ASCs/supernatant while IFN-γ was down-regulated in the presence of ASCs. Conclusion: Accordingly, ASC may act as one of the major players in tumor site with immunomodulatory effects, which may mostly be carried out through direct cellcell interaction.