Design,Synthesis And Biological Evaluation Of P53-MDM2Binding Inhibitors

The p53tumor suppressor is controlled by MDM2, which binds p53and negatively regulates its transcriptional activity and stability. Many tumors overproduce MDM2to impair p53function. Therefore, restoration of p53activity by inhibiting the p53-MDM2binding represents an attractive novel approach to cancer therapy. Recently developed potent and selective small-molecule antagonists of the p53-MDM2interaction have been used to demonstrate the proof-of-concept for this approach.According to previous research and literature summary, a pharmacophore model was set up based on the information of p53-MDM2binding structure and structures of known p53-MDM2binding inhibitors. The pharmacophore model revealed that three hydrophobic groups on the core structure were necessary for a good p53-MDM2binding inhibitor, and the introduction of hydrogen acceptor groups might also improve the inhibitory activities. In our first-round design, three new series of imidazoline derivatives were designed and synthesized using Nultins as lead compounds. The imidazoline scaffold of Nutlins was retained as the core structure with a focus on modifying the phenyl groups on the imidazoline ring and the N-1side chain of Nutlins. Based on the obtained data, a preliminary SAR was disclosed that the2-phenyl group and4,5-di(4-cholo)phenyls were essential for the potency, and the N-1substituents displayed a very important role in remaining the potencies as well. Then a series of novel Nutlin analogues, utilizing carbamates, amino acids, amino-acid esters or amino-acid amides as the N-1substituents were designed and synthesized to discover new p53-MDM2binding inhibitors with enhanced p53-MDM2binding inhibitory activities and anti-proliferative potencies. Then CoMFA study which was carried out based on the obtained data helped in understanding the interaction between the ligand and the receptor.Then, some preliminary work was carried out in order to discover novel scaffold p53-MDM2binding inhibitors:a. a series of152,4,5-triphenyl imidazole derivatives was designed due to the imidazoline could get oxidized into imidazole, and their p53-MDM2binding inhibitory activities were tested as well as their anti-proliferative activities. The result exhibited that some derivatives performed medium inhibitory activities (-20μM), however, most of them showed medium to high anti-proliferative activities, which lead to a new thought in discovering novel p53-MDM2binding inhibitors. Thus, by utilizing classic drug design principle, such as bioisosteric replacement and scaffold hopping, a new series of3-amino pyrazole and3-carboxyl pyrazole was designed, synthesized and evaluated their p53-MDM2binding inhibitory activities and anti-proliferative activities. The result for38obtained compounds was concluded that3-amino pyrazole compounds had improved p53-MDM2binding inhibitory activities (～10μM) though they did not show promising anti-proliferative activities, and3-carboxyl pyrazole compounds was not good for their p53-MDM2binding inhibitory activities. As for the structural diversities, we employed spiro-indolinone compounds, which was reported the most potent compounds so far in vitro, as lead compounds, designed and synthesized a series of new spiro-indolinone derivatives, however, this series showed weak activities against cell lines expressing wtp53, but to cell lines have p53mutated (SW620), some compounds exhibited very promising activities, as a matter of concern, this series of derivatives may take part in other mechanism of p53pathway, and may be valuable for treating p53mutated cancer.Meanwhile, for the purpose of testing p53-MDM2binding inhibitory activities of obtained molecules, MDM2protein was expressed and purified, and a FP-based testing assay was set up for the first time at home.