Targeted Design,structure Optimization And Activity Evalustion Of Sophoridine And Matrine Derivatives

Cancer continues to be a serious threat to human health.Currently,radiotherapy,chemotherapy and surgery are the major clinical techniques used to treat cancer,which are extremely painful and cause serious side effects to the patients.Thus,traditional Chinese medicine has attracted considerable attention for cancer therapy.Sophoridine and matrine,as effective constituents of kushen,are two epimer alkaloids.And they are the lead compounds in drug design due to their simple structure,low side effects and broad-spectrum lbiological activities,including antitumor,antiviral,anti-inflammatory,anti-nociceptive and pesticidal effects.But the moderate antitumor activity urged us to perform their structure optimization of sophoridine and matrine for development of novel anticancer candidates.Top I is an important ribozyme for maintaining the topological structure in the processes of DNA replication,transcription and repairing by cutting a strand of DNA to form a cleavable complex to complete the relaxation of the superhelix and the reconnection with DNA.Considering its highly expressive feature in tumor cells,it has been an effective strategy for cancer therapy through the ability to interfere with the catalytic functions of Top or generating Top-mediated DNA damage.Top-based antitumor drug design is one of the hotspots in the field of drug research.Clinically,approximately 50%of the chemotherapy regimens contain at least one Top inhibitor.On the one hand,this paper was focused on the discovery,optimization design and antitumor mechanism study of novel sophoridine Top I inhibitors based on different molecular binding mode.1.14-modified sophoridine derivatives—discovery of Top I inhibitors with a novel mode of mechanismIn order to obtain chalcone structure and exert antitumor synergistic effect,the a,(3-unsaturated ketone structure was built by introduction of a double bond at 14 position of sophordine with seventeen compounds synthesized.MTT results revealed 2e and 2k performed potent anticancer activity.Docking results verified that sophoridine structure can form hydrogen bond or hydrophobic interaction with protein residues of Top I,while tert-butyl and 3-methyl thienyl group can insert into DNA and formπ-π stacking force with base pairs,resulting in the improvement of activity.These studies provided molecular basis for the further design and optimization of sophordine derivatives.2.Quinolinosophoridinic Top I inhibitorsCamptothecin is one of the most widely studied Top I inhibitors.X-ray crystal data showed that the π-π stacking interaction is an important mode for camptothecin binding with Top I.The discovery of novel binding mode of 14-modified sophoridine derivatives urged us to perform structure hybridization between camptothecin and sophoridine in order to maximize π-π stacking force.Among the eighteen synthesized compounds,3h,31 and 10b exhibited potent ancticancer activity.Moreover,10b can inhibit the activity of Top I,arrest cell cycle at S phase.Docking results showed that the molecular mechanism of these compounds was similar to camptothecin,which verified the feasibility of the design strategy and provided a foundation for the search of antitumor candidate drugs of sophordine.3.Indolo-sophoridine Top I inhibitorsIndole was selected as a privileged planar structure and introduced into sophordine by comparing the molecular mechanisms of camptothecin,indolacazole and indoisoquinoline,followed by thirty compounds were synthesized.It was found that fourteen compounds(4a,6c,6e,6h-6p,10a and 10b)showed strong antitumor activity.Among of them,6e,6i,6m,10a and 10b exhibited Top I inhibitory activity.SAR indicated that the substituent group could influence the π-π stacking force between indole and base pairs by changing the density of electron cloud,then contributed to activity.10b showed good activity against three cancer cells and best Top I inhibitory activity.It can arrest cells at S phase and In vivo antitumor assay showed that 10b can effectively inhibit the growth of tumors with low toxicity and side effects,which can serve as anticancer candidate.In addition,databases of 235 small molecules were constructed to perform the docking with Top I-DNA complex.Six good ligands(SZ21,SZ25,BL25,SZ20,SZ13 and BL24)were obtained to facilitate further design and development of sophoridine-based Top I inhibitors.On the other hand,studies were focused on discovery,design and screening of matrine derivatives as anticancer agents.Although uncertainty of the action target caused blindness for matrine modification,the similarity of L spatial structure between radicicol and matrine urged us to perform conformation modification of matrine to target HSP90.HSP90 is a highly conserved chaperone whose activity is required for the functional maturation and activity of a variety of clients and participated in cell growth,proliferation and metastasis.There are more than 350 types of HSP90’s clients,among of which 48 kinds are associated with tumorigenesis.Taking HSP90 as a tool target can avoid drug resistance.Its active pocket is deep and wide,which is conducive to ligand binding.Eight compounds(21e,22a-g)showed excellent in vitro antitumor effects among the eighteen synthesized matrine derivatives.TSA results showed these compounds displayed good binding force with HSP90,which originally verified matrine derivatives can serve as HSP90 inhibitors and further indicated correlation between activity and targeting effect Compound 22g was chosen as a representative for further evaluations.It can induce cell apoptosis,arrest the cell cycle at the S phase and decrease the level of HSP90 in HeLa cells.Moreover,another five pyrazole(isoxazole)matrine derivatives were also involved.These studies provided foundation for matrine design targeting HSP90 as the structural modification of antitumor drugsIn summary,the structural modification of sophoridine and matrine was carried out by using Top I and HSP90 as targets and the mechanism of their corresponding inhibitors.On the one hand,65 sophoridine derivatives with novel mechanisms were synthesized.On the other hand,23 matrine derivatives were originally synthesized by using HSP90 as targets.It was found that many highly active compounds exhibited excellent antitumor activity at the molecular,cellular and animal levels The mechanism of action of representative compounds was discussed,and new chemical entities of sophoridine and matrine derivatives with high efficiency,low toxicity and broad spectrum were obtained,providing a foundation for the development of original anti-cancer drugs with independent intellectual property rights.