Developing Anticancer Metal(Cu And Fe)Pro-Drug Based On The Human Serum Albumin ⅡA Subdomain

We proposed that we may develop appropriate anticancer metal(Fe and Cu)prodrugs with leaving groups that can bind in the human serum albumin(HSA)ⅡA subdomain because there is a large hydrophobic cavity in the ⅡA subdomain of HSA,and then the N-donor residues(Lys199 or/and His242)of the HSA ⅡA subdomain displace the leaving groups of the metal(Fe and Cu)prodrugs and coordinate with the metal centre,forming stable HSA complexes.Subsequently,N-donor residues of HSA are protonated because of the acidic environment of the cancer cell lysosomal compartment,which decreases their coordination ability with metal ion,allowing metal drugs to be released from the HSA carrier.In this paper,we chased the necessary elements for the organism and synthesizedof 13 metal complexes based on thiosemicarbazone Schiff ligands by the solution method.IR,elemental analysis,mass spectrometry,ESI and single crystal X-ray analysis method were used for characterize these complexes.The single crystal X-ray and UV-vis absorption method were used for the interactions of copper(Ⅱ)or iron(Ⅲ)complexes with human serum albumin(HSA)at the molecular level.The mechanism of the antitumor activity of Copper(Ⅱ)or iron(Ⅲ)complexes and their relationship human serum albumin(HSA)complexes were studied by cell experiments,And the treatment of tumor bearing mice was completed.This paper provides important scientific data for the research and development of new inorganic drugs and albumin as a drug carrier.Details of the study are listed as follows:First,seven copper(Ⅱ)metal complexes were synthesized by the solution method with the formation of the thiosemicarbazone ligand the in this paper,and characterized by IR,ESI-MS,element analysis and single crystal X-ray analysis.Respectively as:[Cu(P4mT)C1](1),Cu(Ap4mT)Cl](2),[Cu(Dp4mT)Cl](3),[Cu(Bp4pT)C1](4),[Cu(Bp4mT)Cl](5),[Cu(Ap44mT)Cl](6)and[Cu(Bp44mT)Cl](7).These 7 copper(Ⅱ)metal complexes are all single nuclear structure,all copper(Ⅱ)compounds are in the single crystal space group,and all contain a copper(Ⅱ)metal atom,a shrinking amino thiourea ligand and a chlorine atom.We synthesized six Fe(Ⅲ)compounds derived from 2-Hydroxy-1-naphthaldehyde thiosemicarbazone(HnT),and characterized by IR,ESI-MS,element analysis and single crystal X-ray analysis.Respectively as:[Fe(HnT)Cl2](8),[Fe(Hn4mT)Cl2](9),[Fe(Hn4pT)Cl2](10),[Fe(Hn44mT)Cl2](11),[Fe(Hn44eT)Cl2](12)和[Fe(Hn4piT)Cl2](13).Single crystal structure analysis showed that all the compounds are in the same shape,the same skeleton,both contain an iron(III)metal atoms,a reduction of the ligand and two chlorine atoms.Secondly,we observed that Cu(P4mT)Cl bound to the HSA sub-domain ⅡA via hydrophobic interactions,but Cu(Bp44mT)Cl(7)bound to the HSA sub-domain ⅡA by His242 replacing the Cl atom of Cu(Bp44mT)Cl(7),and coordinating to Cu.The HSA-Fe(Hn4piT)(HSA-13)complex structure revealed that the Fe(Hn4piT)Cl2 bind to the hydrophobic cavity in HSA ⅡA subdomain,Lys199 and His242 of HSA replace the two Cl ligands of Fe(Hn4piT)Cl2(13),coordinating with Fe.These results can provide evidence for the structure of human serum albumin as a drug carrier.Thirdly,in vivo data revealed that the HSA metal(Fe and Cu)complexes increased metal(Fe and Cu)compounds targeting ability and therapeutic efficacy.Moreover,metal(Fe and Cu)compounds and HSA metal(Fe and Cu)complexes causes cancer cells death likely through multi anticancer mechanism,including promoting cell apoptosis,inhibiting cell cycle in S phase and the intrinsic ROS-mediated mitochondrial pathway,accompanied by the regulation of Bcl-2 family proteins.Tumor bearing mice in vivo experiment showed that the complexes of copper(Ⅱ)or Fe(Ⅲ)complexes and human serum albumin(HSA)complexes can inhibit tumor growth,compared with copper(Ⅱ)or iron(Ⅲ)compound their albumin complex HSA-Cu(Bp44mT)(HSA-7)and HSA-Fe(Hn4piT)(HSA-13)has better therapeutic effect.