Activation of glioma cells generates immune tolerant NKT cells [Cell Biology]

October 23rd, 2014 by Tang, B., Wu, W., Wei, X., Li, Y., Ren, G., Fan, W.

The therapeutic results of glioma are poor currently. Tumor tolerance plays an important role in the pathogenesis of glioma. It is reported that micro RNAs (miR) are associated with tumor development. This study aims to investigate the role of miR-92a in the development of tolerant natural killer T (NKT) cells. In this study, U87 cells (a human glioma cell line) and primary glioma cells were prepared. The assessment of miR-92a was performed by real time RT-PCR. The expression of interleukin (IL)-10 and IL-6 in NKT cells was evaluated by flow cytometry. The results showed that abundant IL-6+ IL-10+ NKT cells were detected in glioma tissue. Culture of glioma cells and NKT cells induced the expression of IL-6 and IL-10 in the NKT cells. Glioma cells expressed miR-92a; the latter played a critical role in the induction of the IL-6 and IL-10 expression in NKT cells. The expression of the antitumor molecules, including perforin, Fas ligand and interferon-γ, was significantly attenuated as compared with control NKT cells. The IL-6+ IL-10+ NKT cells showed the less capability in the induction of apoptosis in glioma cells, but showed the immune suppressor functions on CD8+ T cell activities. We conclude that glioma-derived miR-92a induces IL-6+ IL-10+ NKT cells; this fraction of NKT cells can suppress cytotoxic CD8+ T cells.