A 5'-flanking region polymorphism in toll-like receptor 4 is associated with gastric cancer in a Chinese population

Objective： Inflammation induced by H.pylori colonization in the stomach is related to the development of gastric cancer and the genetic variations of the genes involved in the immune responses modify the host response to the infection. The aim of this study was to evaluate whether polymorphisms in the toll-like receptor 4 （TLR4） gene, a key regulator of both innate and adaptive immunity, were related to the susceptibility to

Human fused NKG2D-IL-15 protein controls xenografted human gastric cancer through the recruitment and activation of NK cells

Interleukin （IL）-15 plays an important role in natural killer （NK） and CD8＋ T-cell proliferation and function and is more effective than IL-2 for tumor immunotherapy. The trans-presentation of IL-15 by neighboring cells is more effective for NK cell activation than its soluble IL-15. In this study, the fusion protein dsNKG2D-IL-15, which consisted of two identical extracellular domains of human NKG2D coupled to human IL-15 via a linker, was engineered in Escherichia coll. DsNKG2D-IL- 15 could efficiently bind to major histocompatibility complex class I chain-related protein A （MICA） of human tumor cells with the two NKG2D domains and trans-present IL-15 to NK or CD8＋ T cells. We transplanted human gastric cancer （SGC-7901） cells into nude mice and mouse melanoma cells with ectopic expression of MICA （B 16BL6-MICA） into C57BL/6 mice. Then, we studied the anti-tumor effects mediated by dsNKG2D-IL-15 in the two xenografted tumor models. Human dsNKG2D-IL-15 exhibited higher efficiency than IL-15 in suppressing gastric cancer growth. Exogenous human dsNKG2D-IL-15 was centrally distributed in the mouse tumor tissues based on in vivo live imaging. The frequencies of human CD56＋ cells infiltrated into the tumor tissues following the injection of peripheral blood mononuclear cells into nude mice bearing human gastric cancer were significantly increased by human dsNKG2D-I L- 15 treatment. Human dsNKG2 D-I L- 15 also delayed the growth of transplanted melanoma （B 16BL6- MICA） by activating and recruiting mouse NK and CD8＋ T cells. The anti-melanoma effect of human dsNKG2D-IL-15 in C57BL/6 mice was mostly decreased by the in vivo depletion of mouse NK cells. These data highlight the potential use of human dsNKG2D-IL-15 for tumor therapy.