Design, Synthesis And Antitumor Activity Evaluation Of Indole-based Derivatives As LSD1 Inhibitors

Histone lysine specific demethylation enzyme 1 (LSD1) was found for the first time in 2004. It is a kind of monoamine oxidase dependent flavin adenine dinucleotide(FAD) and can selectively remove mono-, di-methylated K4 and K9 of histone 3. LSD1 can also can inhibit the expression of tumor suppressor gene p5 3, transcription factor E2F1 and DNA methyltransfer enzyme 1 (DNMTs) to adjust and control the biology function of cell. Numerous studies have found that LSD 1 in many tumor cells (prostate cancer, neuroblastoma, lung cancer, gastric cancer) is high expression and is closely related to the generation and progression of cancer, using LSD1 inhibitors to reduce the amount of expression LSD1 or using RNAi to down-regulate the activity of LSD 1 also can inhibit the growth of tumor cells.Indole compounds are a kind of important molecules with a broad range of biological activity. Our team found a good LSD1 inhibition inhibitor Ict-1-01 containing indole through screening small molecular compounds which were synthesized previously in our laboratory. The IC50 of the compound lct-1-01 inhibiting MGC-803, EC-109 and MCF-7 is 2.378±0.160?M,5.918±1.643?M, 3.912±1.746?M respectively. The IC50 of inhibiting LSD1 also can reach 9.469±9.469?M, and it can combine with the catalytic activity pocket of the LSD1 well through computer simulation of molecular docking. This thesis uses lct-1-01 as the lead compound to study structure-activity relationship of indole benzene and N- benzyl and retain key structure of lactone ring.1.The study of the influence of substitutive groups and positions at indole benzene ringUsing lct-1-01 as the lead compound, we synthesized 11 compounds through retaining lactone ring and benzyl chloride unchanged and introducing electron-withdrawing groups(Cl) and electron-donating groups(CH3O-) etc. in the 4,5,6,7 position of indole ring. We evaluated their inhibitory activity of tumor cells and the result showes that their IC50 is at 0.86pM ?14.26?M. That the H on indole benzene ring is substituted by Cl or CH3O- has no important influence on antitumor activity and the position of the substitutive groups also has no important influence on antitumor activity.2.The optimization of N-benzyl at indole and structure-activity relationship studyBased on the basis of structure-activity relationship of indole benzene ring as well as the availability of 5-chlorine indole derivative, this part optimizes the N-benzyl on the basis of 5-chlorine indole. We synthesized all kinds of new types of derivatives containing thiophene, thiazole, oxazole, pyridine, benzimidazole and quinoline etc. five heterocyclic,six heterocyclic,double loop and multisubstituted benzene ring etc. The result shows that except the part of the compounds' activity disappears or decreases and their IC50 is at 1.93?M ?38.21 ?M. The change of N-benzyl at indole has certain influence to the activity, but it can be replaced.3.The effect on the activity of the 5 position of lct-1-01 substitutedEither small electron-withdrawing groups or small electron-donating groups at indole benzene ring were not significantly affected the activity of lct-1-01 on the basis of preliminary structure-activity relationship study. Therefore, we design to introduce heterocyclic structure at 5 position of indole benzene ring to expect to improve the activity of target compounds. So the 5 position of lct-1-01 was introduced pyridine,pyrazole,pyrimidine etc. five,six heterocyclic structre. The experimental result shows that they have good resistance to tumor cell proliferation,but the activity has no obvious improvement compared with the lead compound.4.Research on the mechanism of target compoundsThe thesis designed and synthesized a total of 38 small molecule compounds, and most of the compounds have a good inhibition of proliferation activity on gastric cancer(MGC- 803), lung cancer (H1299), prostate cancer (PC-3) and esophageal cancer (EC-109). Their IC50 all are at the level of micro Moore. The IC50 of compound ?-2h inhibiting LSD1 and MGC-803 is 1.2?M and 32?M respectively. So the activity of compound II-2h is the best in the thesis and was used as a candidate compound to conduct the research of mechanism. Our team firstly found that LSD1 highly express in clinical samples of gastric cancer cell and tumor cells. So MGC-803 was selected as the experimental cell lines. At the same time compound ?-2h can block MGC-803 in mitosis G2 to promote cancer cell apoptosis. We found compound ?-2h can act on the active catalytic pocket of LSD1 through computer simulation of molecular docking.Our team is studying that compound II-2h affects the expression of LSD1 and LSD1 removes the methyl of H3K4 and H3K9.In conclusion, this thesis found a new kind of LSD 1 inhibitor previously, and we also found a new LSD1 inhibitor which has a good activity in cellular and molecular level on this basis of the study of optimizing structure of the lead compound. Lay a good foundation for further research.