非典型组蛋白去乙酰化酶SIRT2是肿瘤等疾病的潜在新靶标，但目前十分缺乏高活性、选择性且体内有效的SIRT2抑制剂。为此，申请人针对SIRT2变构位点，采用前期参与研发的软件设计并获得了一个新型抑制剂SI-63，它对SIRT2有较高的抑制活性和选择性，且对肝癌细胞HUH7有纳摩尔级抑制作用。然而，SI-63的理化性质较差、酶抑制活性有待提升、体内抗肿瘤活性还有待考察且其原子和分子水平作用机制尚不清楚。鉴于此，本项目将继续开展以下两部分研究：对SI-63进行优化设计、合成及酶活性测试，测定化合物与蛋白复合物晶体结构以阐明其原子水平变构抑制机制，并根据活性数据及晶体结构进行结构再优化；对优选化合物进行体内外抗肿瘤活性及分子水平作用机制研究。本项目的实施将有望获得高品质SIRT2变构抑制剂，为靶向SIRT2的药物研究提供候选化合物，也可为深入探索SIRT2的生物学功能提供探针分子或其前体分子。

Atypical histone deacetylase SIRT2 is new potential drug target for the treatment of cancer and other diseases, but there is still a lack of highly potent, selective and in vivo effective SIRT2 inhibitors at present. To this end, we designed and synthesized a new compound named SI-63 according to the SIRT2 allosteric site using our developed program. The test results showed that SI-63 has good potency and selectivity for SIRT2, and it also exhibits nanomolar level inhibition against hepatic cancer cell line HUH7. However, SI-63 suffers from poor physical and chemical properties, its potency needs to be improved, in vivo anti-tumor activity also remains to be evaluated, as well as its mechanism of action at atomic and molecular levelis not clear. Therefore, this project will continue to carry out following two-part studies: structural optimization design, chemical synthesis and enzymatic activity test for new SI-63 derivatives, determination of complex crystal structure for the selected SIRT2 inhibitors to reveal their allosteric inhibition mechanism at atomic level, and further structural optimization of SIRT2 inhibitors according to the obtained activity data and crystal structure; evaluation of anti-cancer activity of the selected inhibitors in vitro and in vivo, and study of their mechanism of action at molecular level. The implementation of this project is expected to obtain high-quality SIRT2 allosteric inhibitors, and will provide new candidate compounds for targeting SIRT2 drug discovery and development, and provide probe/precursor probe molecules for exploring new SIRT2 biological functions.