Figure 10.

Schematic of SAS and AS101 enhancing the antitumor effects of immunotherapy by inhibiting the VLA-4/IL-10/PD-L1 axis. Both tellurium compounds inactivate VLA-4, which is abundantly expressed on many types of malignant cells, resulting in both the inhibition of IL-10 secretion and PD-L1 expression. The inhibition of IL-10 leads to the proliferation and potentiation of CTLs, which, combined with the loss of PD-L1 on tumor cells, can easily infiltrate the tumor and decrease its volume. Moreover, as shown in this in vitro study, loss of PD-L1 increases tumor cell sensitivity to chemotherapy. IL-10 (interleukin-10). IL-2 (Interleukin 2). TH1 and TH2 (T helper 1 and 2). CTL (cytotoxic T lymphocyte).