Design, Synthesis And Antitumor Activities Of 4-substituted Indoles And Benzodiazepines

Since mechlorethamine hydrochloride was used for the treatment of cancer, the research of anticancer drugs has passed more than seventy years. However, a series of issues such as low treatment and toxic side effects are still existed in most of the anticancer drugs. In recent years, with the discovery of Gleevec as the representative of small molecule targeted anticancer drugs, multiple tinib-drugs entered the clinical. Recently, drawbacks are appeared that targeted drugs are expensive and easily resistant, making it a hot topic to find efficient and less toxic drugs based on new targets and mechanisms.Based on the drug design principle of scaffold hopping, we design and synthesize the small molecule inhibitors targeting the Neddylation pathway and p53-MDM2 pathway respectively. 1. Design, synthesis and antitumor activities of 4-substituted indolesNEDD8 is a protein which in humans is encoded by the NEDD8 gene and is similar to ubiquitin. Catalyzed by an E1 NEDD8-activating enzyme(NAE), an E2 NEDD8-conjugating enzyme and an E3 NEDD8 ligase, NEDD8 connected to the corresponding target protein which is then modificated and regulated. Cullin-RING ligases(CRLs), the largest family of E3 ubiquitin ligases, are responsible for the regulation of ubiquitylation and many key signaling proteins, thus leading to the degradation of various protein. Through modulating CRLs, neddylation regulates many biological processes including cell cycle progression, signal transduction and tumorigenesis. NEDD8 pathway is overexpressed in many human cancers, which leads to abnormally activated CRLs.MLN4924, a small molecule of NAE inhibitor, was discovered to inactivate substrate degradation of CRLs and caused accumulation of CRL substrates. Sustained inhibition of NAE pathway triggered cell cycle-dependent DNA re-replication and leaded to DNA synthesis disorders in cell cycle S phase. Neddylation pathways inhibition has become a new strategy for the treatment of malignant tumors.The first selective NAE inhibitor MLN4924 has entered Phase I clinical trials. Based on the drug design principle of scaffold hopping and the total synthesis route of MLN4924, we designed and synthesized eight novel 4-substituted indole NAE inhibitors. Antitumor activity studies suggested that all compounds showed moderate-intensity activity in seven kinds of tumor cell lines. Both targeted compounds and MLN4924 showed broad-spectrum antitumor activities. Compound 28 showed the highest activities against Saos-2, H1299, U2 OS and HCT116 with an IC50 value of 3.4, 8.62, 11.04 and 11.06 μM, respectively. Compound 19 b showed 60.5% apoptotic rate of 48 h for cell line PANC-1, the cell cycle experiments showed 19 b and 28 arrest cell division in G2/M phase. 2. Design, synthesis and antitumor activities of benzodiazepines The p53, as a tumor suppressor, plays a critical role in DNA repair, differentiation, senescence, apoptosis and cell-cycle arrest. p53 interacts with MDM2 to form a negative feedback path and inhibits protein-protein interaction which increass p53 protein level and leads to cancer cells apoptosis.Therefore, targetting the p53-MDM2 interaction has become a new strategy for the treatment of tumors.A series of benzodiazepine derivatives were designed and synthesised. The inhibitory activities and in vitro antitumor activities were suggested that all compounds exhibited potent inhibitory activity and antitumor potency. Compound 43 had promising antitumor activity against U-2 OS with an IC50 value of 4.17 μM, which was much better than that of nutlin-3. The molecular docking study showed that the designed compounds can insert into the three key amino acid residues of MDM2 protein.