Design,Synthesis And Anti-hepatoma Activity Of MTOR/HDAC Dual Inhibitors Based On Hybrid Molecules

Cancer is one of the major diseases endangering human health and life.In 2020,there were19.29 million new cancer cases and 9.96 million cancer deaths in the world.China’s new cases and deaths ranked the first in the world.Liver cancer is the sixth most frequently diagnosed cancer in the world and the third leading cause of cancer death.China is a country with high incidence of liver cancer,its incidence and mortality are higher than world average level.In2020,liver cancer accounted for 9%of the new cancer cases in China,ranking the fifth;13%of cancer deaths,ranking the second.Thus,the prominent mortality of liver cancer in China should be noticed.Various proteins were verified as the therapeutic targets for liver cancer treatment,mTOR and HDAC were included.The dysregulations of mTOR and HDAC are closely related to the occurrence and development of liver cancer.Studies have shown that the simultaneous inhibition of kinase and HDAC can achieve synergistic effect of anticancer activity,as well as better efficacy.Therefore,development of dual inhibitors for mTOR and HDAC would achieve the synergistic effect of anti-hepatoma activity.Studies of kinase/HDAC dual inhibitors based on hybrid molecules（HMs）has been widely reported in recent years.HMs targeting kinases and HDAC have emerged in many cancer treatment fields.To date,two kinase/HDAC HMs,CUDC-101 and CUDC-907,have entered the clinical trials for the treatment of head and neck cancer,advanced solid tumors,and lymphoma,myeloma,respectively.It is worth noting that HMs have attracted attention because of their unique advantages compared with single active compounds,such as acting on multiple targets.However,the obviously higher molecular weights of most HMs have brought doubts of their druggability.Concerning the advantages and potential problems of HMs,in this study,we firstly evaluated drug-likeness of the reported HMs.The results showed the poor drug-likeness of HMs,however,the fused type hybrid molecules（FHMs）displayed better drug-likeness than linked type hybrid molecules（LHMs）.Based on these findings,we designed two series of mTOR/HDAC HMs by using fusion type molecular hybridization strategy.Sapanisertib（MLN0128,Phase II）and PP121 were selected as mTOR moiety,while an FDA-approved pan-HDAC inhibitor,vorinostat（SAHA）,was chosen as the HDAC inhibitory moiety.The designed HMs were synthesized and their bioactivities were systematically studied.Notably,DI06,an MLN0128-based hybrid,exhibited antiproliferative activity against Hep G2 cells with an IC₅₀ value of 1.61μM,which was better than both of the parent drugs(MLN0128,IC₅₀=2.13μM and SAHA,IC₅₀=2.26μM).In vitro enzyme inhibition assays indicated that DI06 achieved dual inhibition against mTOR kinase and HDAC at a nanomolar level.Further cellular experiments have shown that DI06 can induce apoptosis,block the cell cycle in the G0/G1 phase,and inhibit cell migration of Hep G2 cells.In addition,DI06 possessed good stability in rat liver microsome.Moreover,the interaction modes of DI06 with mTOR and HDAC,as well as the its druggability were predicted through molecular docking,ADMET prediction and Ro5 analysis.