营养因素在免疫反应中起着至关重要的作用。已知肿瘤引起的营养缺乏会影响抗肿瘤免疫力。在这里，我们证明胰腺导管腺癌 (PDAC) 细胞可以通过限制维生素 B6 (VB6) 的可及性来抑制 NK 细胞的细胞毒性。 PDAC 细胞主动消耗 VB6 以支持一碳代谢，从而支持肿瘤细胞生长，导致肿瘤微环境中 VB6 缺乏。相比之下，NK 细胞需要 VB6 来分解细胞内糖原，而 VB6 是 NK 细胞激活的关键能源。 VB6 补充与一碳代谢阻断相结合可有效减轻体内肿瘤负荷。我们的研究结果加深了对微量营养素在调节癌症进展和抗肿瘤免疫中关键作用的理解，并为开发针对 PDAC 的新型治疗策略开辟了新途径。

Nutritional factors play crucial roles in immune responses. The tumor-caused nutritional deficiencies are known to affect anti-tumor immunity. Here, we demonstrate that pancreatic ductal adenocarcinoma (PDAC) cells can suppress NK cell cytotoxicity by restricting the accessibility of vitamin B6 (VB6). PDAC cells actively consume VB6 to support one-carbon metabolism, and thus tumor cell growth, causing VB6 deprivation in the tumor microenvironment. In comparison, NK cells require VB6 for intracellular glycogen breakdown, which serves as a critical energy source for NK cell activation. VB6 supplementation in combination with one-carbon metabolism blockage effectively diminishes tumor burden in vivo. Our results expand the understanding of the critical role of micronutrients in regulating cancer progression and anti-tumor immunity, and open new avenues for developing novel therapeutic strategies against PDAC.