Wnt pathway activator TWS119 enhances the proliferation and cytolytic activity of human γδT cells against colon cancer

gamma delta T cells are a distinct T-cell subset that display unique characteristics regarding T-cell receptor gene usage, tissue tropism and antigen recognition. Adoptive gamma delta T cell transfer therapy has recently been gaining importance as an efficient approach in cancer immunotherapy. However, exploiting gamma delta T cell response for tumour immunotherapy is a challenge due to cell numbers, activities and differentiation states that minimize the clinical therapeutic effects. Previous studies have indicated that the wnt/beta-catenin signalling pathway plays a crucial role in the differentiation, survival and enhancement of the immune response of T lymphocytes. In this study, we sought to evaluate whether the activation of the wnt/beta-catenin pathway through inhibition of glycogen synthase kinase-3 beta (GSK-3 beta) using 4,6-disubstituted pyrrolopyrimidine (TWS119) could be an efficient strategy to improve the proliferation, differentiation and cytolytic activity of gamma delta T cells against colon cancer cells. Remarkably, we found that TWS119 significantly enhanced the proliferation and survival of gamma delta T cells via activation of the mammalian target of rapamycin (mTOR) pathway, upregulation of the expression of the anti-apoptotic protein Bcl-2 and inhibition of cleaved caspase-3 in addition to the Wnt pathway. Our results also showed that enhancement of the cytolytic activity of gamma delta T cells against human colon cancer cells by TWS119 was chiefly associated with upregulation of the expression of perforin and granzyme B in vitro and in vivo. Additionally, TWS119 can induce the expression of CD62L or CCR5 to generate a population of CD62L(+)gamma delta T or CCR5(+)gamma delta T cells in a dosedependent manner. These findings suggested that TWS119 could be a useful complementary agent for improving gamma delta T cell-based immunotherapy.