Design,synthesis And Preliminary Bioactivity Evaluations Of Anti-cancer Drugs Based On Zinc-Dependent Enzymes

Zinc(?)is a metal ion that is frequently used as a cofactor in enzymes and that can function in a number of different roles.Histone deacetylases(HDACs)and matrix metalloproteinases(MMPs)are two important members of the zinc hydrolase family and play a crucial role in tumorigenesis.In recent years,a variety of HDACIs(HDACIs)and MMP inhibitors(MMPIs)have been discovered,and their anti-tumor mechanisms have gradually been elucidated.The development of more efficient HDACIs and MMPIs is one of the effective ways for cancer treatment.HDACs and histone acetyltransferases(HATs)played a pivotal role in epigenetic regulation of gene expression and had pleiotropic effects at the cellular and systemic levels.HDACs removed the acetyl groups of lysine residues,leading to chromatin structure becoming contraction and therewith repressing transcription.HATs opposed the effect of HDACs.Human HDACs had 18 members and they were divided into four classes.It has been reported that HDACIs can participate in many physiological processes such as cell cycle arrest,apoptosis,autophagy and angiogenesis,and exert anti-cancer effects.Matrix metalloproteases(MMPs)are zinc-dependent endopeptidases that proteolytically degrade various components of the extracellular matrix(ECM).To date,at least 24 MMPs have been identified in human,which could be classified into five subfamilies based on their specificities.MMPs promote the invasion and angiogenesis of tumor by protein degradation of extracellular matrix(ECM)and basement membrane.By inhibiting the activity of MMPs,MMPIs can inhibit the metastasis and angiogenesis of tumor cells,and exert anti-cancer effects.Design,synthesis and biological evaluation of quinoline derivatives as HDAC inhibitorsQuinoline hydroxamic acid derivatives has been proved to exert HDAC inhibitory activities and antiproliferative activities in our previous study.Meanwhile,N-hydroxycinnamamide and N-hydroxybenzamide,which serve as both ZBGs and linker groups,were widely used fragments in current HDACIs design.Guided by these structural analyses above,we developed a series of new HDACIs by utilizing quinoline derivatives as cap group and utilized N-hydroxycinnamamide and N-hydroxybenzamide as the ZBG and linker groups.All target compounds were evaluated for their in vitro HDAC inhibitory activities and anti-proliferative activities and the best compound 4a surpass SAHA in both enzymatic inhibitory activity and cellular anti-proliferative activity.In terms of HDAC isoforms selectivity,compounds 4a exhibited preferable inhibition for class I HDACs,especially for HDAC8,the IC50 value(442 nM)was much lower than that of Vorinostat(7468 nM).Subsequently,we performed class ?&?a HDACs whole cell enzyme assay to evaluate inhibitory activity in whole cell context.Compounds 4a and 4e displayed much better cellular activity for class ? HDACs than that for class ?a HDACs,which indicated that 4a and 4e might be potent class I HDAC inhibitors.Meanwhile,flow cytometry analysis showed that compound 4a and 4e can promote cell apoptosis in vitro.Western Blot assay showed that 4a down-regulated the expression of Ac-HH3 and Ac-tubulin in K562 cell line.Design,synthesis and preliminary bioactivity evaluations of benzimidazole derivatives with dual DNA binding and HDAC inhibitory activityLiteratures have reported many small molecule with DNA-binding activity binding to DNA in a covalent or non-covalent form.DNA alkylation belongs to covalent binding and forms intra-strand or cross-linking of DNA,which leads to mitosis inhibition.Non-covalent binding consists of intercalation and groove binding,which act as an anti-tumor drug by affecting on DNA replication,transcription.In recent years,new molecules with dual DNA binding and HDAC inhibitory activity have been reported.In our studies,a series of new HDACIs were developed by introducing DNA binding fragement(benzimidazole)as cap group.All target compounds were evaluated for their in vitro HDAC inhibitory activities and HDAC isoforms activities.Compounds 22e,221,25k and 251 possessed best inhibitory activity.After evaluation of UV-visible spectroscopy,CD and ITC,22e and 25k could spontaneously bind to DNA.MTT assay and flow cytometry analysis showed that 25k can inhibit tumor proliferation and promote cell apoptosis in vitro.Western Blot assay showed that 25k induced upregulation of Ac-HH3 and Ac-tubulin in tumor cells and induced apoptosis by cleavage of caspase3.Meanwhile,as a DNA-binding molecule,25k induces down-regulation of ssrpl and spt16 to promote tumor cell death.Design,synthesis and preliminary bioactivity evaluations of 8-hydroxyquinoline derivatives as matrix metalloproteinase(MMP)inhibitorsAs a commonly used zinc-binding group,hydroxamic acids have been widely used in the development of MMPs inhibitors.However,several hydroxamate-based MMP inhibitors failed in clinical trial due to low isoform selectivity and various toxicities,such as joint stiffness,swelling and arthralgia.Currently,developing new non-hydroxamate structure as zin-binding group become an important issues for the development of MMPs inhibitors.As an previliged scaffold in medicinal chemistry,the derivatives of 8-hydroxyquinoline were found to possess inhibitory activities against MMPs in recent years.Further structural modification suggested that aromatic substitutions at either the 5-or 7-positions of 8-hydroxyquinoline could yield MMP-2 inhibitors.Docking analysis suggested that 8-hydroxyquinoline chelated the zinc ion and lead compound B is surrounded by less occupied pockets(e.g.S1 pocket and S1'pocket).Inspired by these analyses above,we designed a new series of MMP inhibitors using 8-hydroxyquinoline as the zinc binding group.Flexible linkers with different lengths were introduced between 8-hydroxyquinoline and aromatic substitutions of quinoline to improve interactions with these pockets,especially interactions with S1' pocket.Preliminary biological evaluation suggestd that most active compounds 30e and 30h not only displayed good inhibitory activities against MMP-2/9 with IC50 at submicromolar level,but also possessed potent anti-proliferative,anti-invasive and anti-angiogenesis activity in A549 cell line.Western blot also revealed that 30e and 30h down-regulate the expression of MMP-2 and MMP-9 in A549 cell line.Moreover,flow cytometry analysis indicated that compound 30e could promote apoptosis of A549 cells in vitro.Molecular docking analysis also revealed favorable binding modes of 30e in the active sites of MMP-2 and MMP-9.