PHGDH作为丝氨酸合成途径中的关键限速酶已成为目前肿瘤代谢重编程及抗肿瘤药物研究的新靶标。苦蘵为茄科酸浆属清热解毒中药，其中富含睡茄内酯成分。项目组前期研究发现苦蘵中睡茄内酯Withangulatin A(WGA)具有显著的抗结肠癌作用，能够与PHGDH结合并抑制其酶活。本项目拟在前期研究基础上，通过重组蛋白及生物膜层干涉等实验确证WGA与PHGDH的结合，并以靶标代谢流分析等手段评价WGA对结肠癌细胞中丝氨酸合成途径的调控作用，以明确WGA靶向PHGDH干预丝氨酸合成途径的效应；进一步采用定点突变，质谱鉴定等技术，探究WGA与PHGDH的结合位点及作用形式，并对PHGDH调控的下游分子进行验证，阐明WGA靶向PHGDH的抗结肠癌作用机理。本项目通过发现并阐明WGA的抗结肠癌作用靶标及机理，不仅为阐明中药苦蘵的抗肿瘤功效提供依据，而且为基于睡茄内酯的中药抗肿瘤新药创制奠定基础。

PHGDH, as the key enzyme in the first step of serine biosynthesis, becomes the target in the research of cancer metabolic reprogramming and anti-tumor drug research. Physalis angulata L as a traditional chinese medicine of Physalis, which is rich in withanolides. The preliminary study of our group showed that Withangulatin A(WGA) had significant anti-tumor effect in colon cancer, which is a withanolide in the Physalis angulata L. Further study showed that WGA could combine with PHGDH and inhibit the enzyme activity of PHGDH. Based on previous research, this project will further confirm the target effect of WGA on PHGDH by recombinant proteins and BLI, then evaluate the effect of WGA on the serine biosynthesis by metabolite analysis to verify the targeting effect of WGA on PHGDH in colon cancer. With the using of pull down, mass spectrum, site-specific mutation, etc, this project will further investigate the binding site and action form of WGA and PHGDH, and evaluate the signal molecules regulated by PHGDH. This project will illuminate the target and anti-tumor mechanism of WGA in colon cancer, which is not only provide the evidence on the anti-tumor effect of Physalis angulata L, but also establish the foundation in the anti-tumor drug development which is based on the withanolides.