The amino acid taurine is marketed as a nutritional supplement. Cao et al. now show that taurine can enhance the malignant behaviour of cancer cells, but also increase the survival and effector functions of CD8⁺ T cells. In mouse models of gastric cancer and melanoma, intratumoural injection of taurine promoted tumour growth in immunocompromised mice, but inhibited tumour growth in immunocompetent mice. Further analysis showed that tumour cells consume taurine via the membrane transporter SLC6A6, and that SLC6A6 expression is a negative prognostic indicator for different types of cancer. The authors found that tumour cells can outcompete CD8⁺ T cells for taurine by overexpressing SLC6A6, which induces endoplasmic reticulum (ER) stress in the CD8⁺ T cells. This promotes expression of the transcription factor ATF4, which upregulates immune checkpoint genes and induces T cell exhaustion. Taurine supplementation in mice repressed Atf4 transcription and promoted the survival and function of CD8⁺ T cells. In mouse models of gastric cancer, chemotherapy upregulated SLC6A6 in cancer cells. However, taurine supplementation increased the efficacy of chemotherapy, indicating that its capacity to re-invigorate CD8⁺ T cells outweighs its direct tumour-promoting effects. A clinical trial has been initiated to test oral taurine in combination with chemotherapy or immunotherapy in patients with gastric cancer.

氨基酸牛磺酸作为营养补充剂销售。曹等人。现在表明，牛磺酸可以增强癌细胞的恶性行为，还可以增加CD8 ⁺ T细胞的存活和效应功能。在胃癌和黑色素瘤小鼠模型中，瘤内注射牛磺酸可促进免疫功能低下小鼠的肿瘤生长，但抑制免疫功能正常小鼠的肿瘤生长。进一步分析表明，肿瘤细胞通过膜转运蛋白SLC6A6消耗牛磺酸，并且SLC6A6表达是不同类型癌症的负面预后指标。作者发现，肿瘤细胞可以通过过度表达 SLC6A6 来竞争^{牛磺酸，从而在 CD8 + T}细胞中诱导内质网 (ER) 应激。这会促进转录因子 ATF4 的表达，从而上调免疫检查点基因并诱导 T 细胞耗竭。小鼠体内补充牛磺酸可抑制Atf4转录并促进 CD8 ⁺ T 细胞的存活和功能。在小鼠胃癌模型中，化疗上调了癌细胞中的 SLC6A6。然而，补充牛磺酸提高了化疗的疗效，表明其重新激活 CD8 ⁺ T 细胞的能力超过了其直接的肿瘤促进作用。一项临床试验已启动，以测试口服牛磺酸与胃癌患者的化疗或免疫疗法相结合。