Study On Multi-target Histone Deacetylase Inhibitors And Glutathione Transferase Inhibitors

In this work,two kinds of anticancer compounds,multi-target HDAC inhibitors and GST P1-1 inhibitors,were designed and synthesized.Their anticancer mechanism was also studied.PART Ⅰ:The inhibition of HDAC can exert anticancer effect via multi-mechanisms including the suppression of cancer cell viability,migration,invasion,angiogenesis,proliferation,DNA damage and the induction of cell apoptosis.Therefore,HDAC have been becoming hot point in the anticancer study.So far,five HDAC inhibitors have been approved to cure hematological malignancies.Despite their success in the treatment of hematological malignancies,HDAC inhibitors alone face an embarrassing situation because they exhibit low clinic efficiency on solid tumors.Research shows that some HDAC inhibitors have been used to combine with other clinical drugs to achieve synergistic therapeutic effects.Although drug combination has good anticancer efficiency,it also faces the drawbacks of enhanced side effects,unpredicted pharmacokinetic properties and drug-drug interactions.Hence,single molecule drugs with multifunctions have become a potential alternative of the drug combination therapy.Previous research indicated that HDAC inhibitors and p53(transcriptional factor)activators could synergistically exert anticancer effect,because HDAC inhibitors can induce acetylation of the Lys382 site of p53 to activate the p53 pathway.These hint that it would be an effective strategy to develop small molecule compound with both HDAC inhibitory property and p53 activating capacity.So in this work,phthalazino[1,2-b]-quinazolinone units,proved to possess the p53 activating effect,have been chosen as a cap moiety(interacts with the surface residues of HDAC)and hydroxamic acid or orthoaminoanilide as a ZBG group(zinc binding group),which are connected by linkers to obtain a series of new compounds for screening multi-target HDAC inhibitors.Among the target compounds,I2-16 exhibited strong in vitro activity toward the tested cancer cells and HDAC subtypes with good liver microsome stability.Further mechanism study revealed that compound I2-16 exerted potent anticancer effects by enhancing the acetylation of H3 and α-tubulin,and activating the p53 signal pathway.In addition,I2-16 arrested the cell cycle at G2 phase in Hep G2 cells and induce cell apoptosis via activating the mitochondrial apoptotic pathway.Significantly,I2-16 exhibited prominent in vivo anticancer activity in the Hep G2 xenograft model,which was stronger than positive control drug SAHA(Vorinostat).Since erianin exerts anticancer effect via inducing DNA damage,cell apoptosis,and cell cycle arresting,we chose the erianin moiety as a Cap group and hydroxamic acid or ortho-aminoanilide as a ZBG group,which are connected by linkers to obtain a series of new multi-target HDAC inhibitors.Among them,representative compound I3-3 possessed considerable inhibitory effect toward cancer cells and HDAC subtypes.Compound I3-3could increase the expression of p H2 AX,induce DNA damage,arrest cell cycle at G2 phase,and meanwhile induce cancer cell apoptosis in a dose dependent manner.Molecular docking study confirmed the binding mode between the compound I3-3 and HADC1 or HDAC6 protein.PART Ⅱ:GST P1-1 has multiple biological functions and is always highly expressed in many kinds of cancer cells.However,the expression level of GST P1-1 in normal cells is low.A drug targeting GST P1-1 can either exert potent anticancer effects on cancer cells or weaken toxicity towards normal cells.NBDHEX is a kind of GST P1-1 inhibitor and possesses potent anticancer efficiency toward melanoma and osteosarcoma.Despite the high expression of GST P1-1 in solid tumor,the specificity of NBDHEX is poor,because it has high inhibition ability to the subtype of GST M2-2 that is highly expressed in muscle tissue,which can lead to the emergence of side effects.In addition,low aqueous solubility of NBDHEX also limits its biological application.Based on the NBDHEX structure,a series of 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol derivatives as GST P1-1 inhibitors were designed,synthesized,and biologically evaluated.Among them,compound I5-14 showed good aqueous solubility and had a higher selectivity of GST P1-1 than its parent molecule.It can overcome the disadvantages of NBDHEX to a certain extent.Biological mechanism research demonstrated that I5-14 arrested the cell cycle at the G2 phase and induced cell apoptosis in a dose-dependent manner.Like NBDHEX,I5-14 displayed acceptable pharmacokinetic parameters.The in vivo experiments on 143 b xenograft models demonstrated that I5-14 significantly reduced tumor growth in a dose-dependent manner and showed stronger antitumor activity than NBDHEX without obvious toxic and side effects even at high dose.