This phenomenon suggests Vistusertib that in patients with breast cancer, a mechanism may exist that can increase the proportion of Tregs. We also added 1-MT, the specific inhibitor of IDO in the co-culture system composing of CHO/IDO cells and CD3+T cells to elucidate the regulatory effect of IDO both in promoting apoptosis and increasing Tregs. It demonstrated that 1-MT could efficiently reversed enhancement of T cells apoptosis and increased Tregs proportion in vitro.
It implied that IDO is indeed responsible for the changes observed in vitro. Some studies have indicated a close relationship between IDO and regulatory T cells. Some dendritic cells in the lymph nodes draining tumors that express IDO had local infiltration
of Tregs cells [21, 22, 22, 24]. Furthermore, when IDO was expressed in the primary tumor of breast cancer patients, there was a direct correlation between an increase in volume of the primary breast cancer tumor and the proportion of Tregs in the peripheral circulation NVP-BSK805 cost [23]. Tregs cells are also likely to be involved in IDO-mediated tumor immune tolerance [11, 12]. To investigate this hypothesis, we established a CHO cell line that stably expressed IDO. Western blot analysis confirmed that CHO cells transfected with IDO expressed IDO protein with an expected molecular weight of approximately 42 kDa. At the same time, we detected a decrease in tryptophan in the culture medium, and an increase in its metabolite kynurenine, suggesting that IDO expressed
by the transfected cells was functional and could lead to the depletion of tryptophan in the environment. Analysis of apoptosis after co-culture of IDO-expressing CHO cells and CD3+T cells Isoconazole isolated from the peripheral blood of patients with breast cancer showed that a significantly higher proportion of CD3+T cells were apoptotic than in the control group, suggesting that IDO may affect the T cell proliferation and induce T cell apoptosis. In our recent study, we found that cell proliferation and IL-2 synthesis triggered by the TCR activating anti-CD3 monoclonal antibody OKT3 was inhibited in T-cells which were co-cultured with IDO-expressing CHO cells. Furthermore, co-cultured of CHO/IDO with T-cells could inhibit Vav1 mRNA and protein expression in T-cells. However, an inhibitor of IDO, 1-MT, attenuated CHO/IDO-induced decrease of T-cell proliferation, IL-2 find more levels in T-cells and inhibition of Vav1 [11]. These data suggested that Vav1 is a target molecule involved in the regulatory effect of IDO on T-cells. Whether IDO can induce the maturation and differentiation of Tregs is unclear.