吲哚胺2,3-双加氧酶(IDO)的色胺酮类抑制剂筛选及其体外抗肿瘤作用

 目的  评价色胺酮衍生物吲哚胺2,3-双加氧酶 (indoleamine 2,3-dioxygenase,IDO)的抑制活性,并研究其作为 IDO 抑制剂的抗肿瘤作用。方法  采用基因工程手段表达、纯化重组人 IDO (rhIDO),建立 IDO 活性检测体系;以色胺酮衍生物作为对象,进行 IDO 抑制活性初筛,对抑制类型、半数抑制浓度以及抑制常数进行测定;构建高表达人 IDO 的 pcDNA3.1(+) hIDO 转染 HEK 293 细胞,评价色胺酮衍生物在细胞水平上的 IDO 抑制活性;采用 MTT 比色法考察色胺酮衍生物3对人非小细胞肺癌A549细胞的生长抑制作用。结果  6个被测色胺酮衍生物均具有IDO抑制活性,且细胞水平上的抑制效力高于酶活水平,抑制效力均优于目前通用的IDO抑制剂1 甲基色氨酸(1-methyl-tryptophan,1-MT)。色胺酮衍生物 3 作为最强的 IDO 抑制剂,其Ki值为 0.161 μmol/L。MTT 实验结果显示,色胺酮衍生物3 显著抑制 A549 细胞生长,IC50 为 8.77 μmol/L。结论  色胺酮衍生物是一类新型高效的 IDO 抑制剂,在体外对 A549 细胞具有较强的抗肿瘤活性。

Screening of tryptanthrin derivatives of indoleamine 2,3-dioxygenase(IDO) inhibitor and their antitumor activity in vitro

Objective  To evaluate the inhibitory activity of tryptanthrin derivatives of indoleamine 2,3-dioxygenase (IDO),and to explore the effects on human non small cell lung cancer A549 cell growth.Methods  IDO activity assay system was established with recombinant human IDO (rhIDO),which was expressed and purified by the technology of genetic engineering.Based on the system,we detected the IDO inhibitory activity of tryptanthrin derivatives,and determined the inhibition type,kinetic parameters and IC50 values.We also evaluated the IDO inhibitory effects of tryptanthrin derivatives on HEK 293 cells transfected with pcDNA3.1(+) hIDO.Inhibitory activity of tryptanthrin derivatives on A549 cell growth inhibition was analysed by MTT assay.Results  Six tryptanthrin derivatives displayed higher IDO inhibitory activity than 1-methyl tryptophan (1-MT),which is the commonly used IDO inhibitor.IC50 values of tryptanthrin derivatives,obtained from the HEK 293 cell based assay,were much lower than that from the enzyme assay.Compound 3 was the best inhibitor and had Ki value of 0.161 μmol/L.Treating A549 cells with 3 remarkably inhibited the cell growth,and its IC50 value was 8.77 μmol/L.Conclusions  Tryptanthrin derivatives are novel and potent IDO inhibitors,and can significantly inhibit human non-small cell lung cancer A549 cell growth in vitro.