| Cancer is one of the major diseases that endanger human life seriously. The death rate of cancer patients is up to 25%or so in the world now.In order to conquer the disease,scientists have been making great efforts.At the moment,people treat cancer by two methods:one is chemo therapy,the other is radiopharmaceutical therapy.Almost all anticancer medicines make against normal cells while killing cancer cells.Therefore,it is important to improve the selectivity,to increase efficiency and to decrease side effect of anticancer medicines.We can find the third method to treat cancer,to treat cancer from gene. The development of molecular biology and molecular pharmacology made it possible for people to comprehend some life phenomena;and to find sensitive nucleic acid probe and effective curative by molecular design.Most of anticancer agent targets in biology body are DNA molecules,which have three action styles:(1) Drugs and DNA formed non-covalent compounds,and combine with DNA through hydrogen bond.When duplex come to dissociate, drugs will deviate from DNA.(2) Drugs and DNA formed covalent compounds,and combine with DNA through covalent bond.If they are between duplex,they can form crosslink between duplex and thus prevent DNA from unlinking.(3) Drugs combine with DNA selectively,and the structure of DNA will become insatable,which will make single-strand or double-strand breakable,and degrade template DNA.So,to rupture DNA from specific sequence was the main attack direction in effectively annihilaing cancer cells and protect normal cells.Thus,new chemical nucleases and anticancer medicines may be exploited and developed.The post of humankind genome sequence took foundation of rupturing DNA special sequence.Research indicated that DNA,the gene carrier,can make base mismatched because of the miscopy,attack by chemistry contaminate,abuse drug and damage by electromagnetism radiant. Commonly,renovating system in cell can renovate it in time,but if renovation failed,base mismatch will induce seed system DNA mutation, which may cause the cancers or genetic diseases.People have found that permanent error of gene code takes so much proportion in pathogenesis of most diseases.Because small molecule combine with DNA strongly,and its solidity is small,it can enter into cells,and act with DNA directly.Up to date,many research groups have focused on recognizing of small molecule to DNA,and they have gained much headway.The DNA recognizing system act with DNA by non-covalent and covalent bond,such as anticancer drugs-cisplatin combines with DNA by covalent bond.There are two kinds of non-covalent bond recognizing system,one is groove bond reagent,whose form major and minor groove complement each other,and it forms hydrogen by Van der Waals bond,combines with base or combine with DNA in major and minor groove,such as Distamycin,SN7167 and polyamine compounds;The other is insert reagent,with isocyclo plane ligand,can insert into base,which can change DNA configuration,such as Nogalamycin and inertia metal-pyridine mix compounds.And this is researched by our task group and JI-liang-nian academician task group.[Rh(bpy)2(chrysi)]3+ has been synthesized by Barton professor in America,which can act with DNA by insert style,and can specially recognize C:C mismatch.Hannon professor's task group in Birmingham University have found one new drug-DNA action model,which is 3-way DNA junction.The work has published in Angewandte Chemic (2006 volume 45 issue 8 pages 1227-31).The famous biochemist Stephen Neidle has studied small molecular recognizing DNA and designed anti cancer drugs for many years.He introduced about small molecular recognizing DNA in his book-《Nucleic Acid Structure and Recognition》. Our task group have found many significant research points.It is noticeable that,among all mismatched base pairs,the sheared G:A is the least efficient repaired base mismatch.The result of research indicated that DNA containing G:A mismatch has wider minor groove,moreover, nucleotide A glides from chain and forms crosslinking accumulation with complementary nucleotide A.Therefore,this paper focuses on many kinds of special recognizing G:A system,and study their more fine,truly interaction. Which can provide some theoretic gist for examining molecule disease.For different mismatch corresponds mismatch recognizing system,there are some chiral metal compounds which have aroma big ring ligand can recognize DNA mismatch system.There are so many difficulties in their interaction:1) In despite of the fact that people have understood the multiformity of DNA configuration,at the moment,people understand their faultiness,what's more different study means will lead to different results, therefore,it is very complicated.2) Because the interaction of the system is in solution and it is in dynamic,in normal,we can only find the Einstein shift and ultraviolet shift,hyperchromism and hypochromism,which is phenomenological indirect result and difficult to corroborate.Because of the above reasons,we have studied the interaction of metal compounds with DNA by 2D NOESY,TOCSY NMR.At the same time,we have studied the fine circs and rule by molecule simulate.We have designed mismatch oligonucleotide d(CCGAATGAGG)2 containing two G:A mismatch in different position and normal oligonucleotide d(CCTAATTAGG)2.At the moment,we have synthesized three metal complexes and made them interact with mismatch oligonucleotide d(CCGAATGAGG)2 and normal oligonucleotide d(CCTAATTAGG)2.And the results are satisfying.Furthermore,we have found some small molecular systems can incise PBR322DNA,and some other metal complexes can effectively inhibit stomach cancer cells.We conclude the above work as follows:1.We have found that 6-benzyl-amion-purine can combine with Co2+,Ni2+, and they can influence the interaction between drug molecular and DNA. The interaction between 6-benzyl-amion-purine and 6-benzyl-amion-purine Co2+,Ni2+system with the plasmid DNA were studied by UV spetra,fluorescence spetra,Scatchard plot.The results indicated that the action of 6-benzyl-amion-purine,6-benzyl-amion-purine Co2+,Ni2+system and DNA was electrostatic action.At the same time,we have found that 8-azaadenine can complex with Co2+,Cu2+ and the action of them with DNA was intercalation action.2.We have found the general anticarcinogen(applied to L1210 and P388 leucocythemia,SA180 sarkomycin,leucoma,mastocarcinoma,carcinoma of ovary,carcinoma of stomach,B16 melanic cancer,lung cancer, colorectal carcinoma and so on)—Epirubicin can combined with Cu2+by 2:5,furthermore,we studied the interaction of Epirubicin-Cu2+ system with the plasmid DNA by spectra,viscosity,cyclic voltammetry, electrophoresis,etc.The results showed that the interaction of Epirubicin and Epirubicin-Cu2+system with DNA was intercalation action.At the same time,Epirubicin-Cu2+system can cleave pBR 322 DNA effectively into linear with 1.0×10-5mol·L-1.3.The complex Mg(Sal2trien) was synthesized for the first time and the interaction of Mg(Sal2trien) with DNA was studied by spectra,viscosity, cyclic voltammetry,electrophoresis,etc.The results showed that the binding points of the complex with the DNA were uncompetitive type compared with EB,and this complex can cleave pBR 322 DNA effectively into nick with 10-6 mol·L-1,and it can cleave pBR 322 DNA effectively into linear with 10×10-5 mol·L-1.Its cleavage mechanism was possibly the hydrolysis cleavage action to the phosphate diester.This result provided available information for exploration of man-made nuclease and discussion of the application of complex in medicine exploration and molecular biology from molecular level.4.We have synthesized[Ru(phen)2tpphz](PF6)2·2H2O and [Co(phen)2tpphz]Cl(PF6)2·2H2O.The effects of [Ru(phen)Etpphz](PF6)2·2H2O and[Co(phen)2tpphz]Cl(PF6)2·2H2O on cell viability were tested by using the MTT assay.The results showed that 1nM[Co(phen)2tpphz]Cl(PF6)2·2H2O can result in a decrease (â…¡%=22.2%)in the percentage of cell viability when compared with controls,1μM[Co(phen)2tpphz]Cl(PF6)2·2H2O can result in a decrease (â…¡%=30.6%)in the percentage of cell viability when compared with controls,1nM[Ru(phen)2tpphz](PF6)2·2H2O can result in a decrease (â…¡%=25.2%)in the percentage of cell viability when compared with controls,1μM[Ru(phen)2tpphz](PF6)2·2H2O can result in a decrease (â…¡%=48.6%)in the percentage of cell viability when compared with controls.These results showed that[Co(phen)2tpphz]Cl(PF6)2·2H2O and [Ru(phen)2tpphz](PF6)2·2H2O can effectively inhibit cancer cells At the same time we have found that[Co(phen)2tpphz]Cl(PF6)2·2H2O and [Ru(phen)2tpphz](PF6)2·2H2O can cleave pBR 322 DNA into linear form with 5×10-6 mol·L-1.5.We have studied the interaction between three metal complexes [Co(phen)2(HPIP)]Cl3;[Co(phen)2(DPQ)]Cl3;[Co(phen)2(HNAIP)]Cl3 with mismatch oligonucleotide d(CCGAATGAGG)2 containing the sheared G:A and normal oligonucleotide d(CCTAATTAGG)2 by 2D NMR. the results are as follows:For[Co(phen)2(HPIP)]Cl3:A lot of intermolecular NOE cross-peaks from[Co(phen)2(HPIP)]Cl3 and the sheared G:A region appear in NOESY spectra,and the intensity of the sequential NOE cross-peaks decrease or diminish.From the phenomena and the spectra,we have concluded that the complex[Co(phen)2(HPIP)]Cl3 can insert into base T6G7 from major groove.[Co(phen)2(HPIP)]Cl3 interact with normal oligonucleotide d(CCTAATTAGG)2 at terminal region from minor groove.31p NMR indicate that[Co(phen)2(HPIP)]Cl3 cannot change the phosphor framework of oligonucleotide.From molecule simulate we can see that [Co(phen)2HPIP]3+ can recognize normal and sheared DNA,and can recognize isomer,DNA groove,location point.During the process of recognizing sheared DNA,[Co(phen)2(HPIP)]Cl3 can not recognize isomer evidently.It can interaction with sheared DNA at T6G7 region from major groove by structureâ…¡;It can interaction with normal DNA at terminal region from minor groove by structureâ… ,and D-isomer will be enriched.The above results indicate that 2D NMR can consistent with the result of molecular simulate.For[Co(phen)2(DPQ)]Cl3,A lot of intermolecular NOE cross-peaks from[Co(phen)2(DPQ)]Cl3 and the terminal G:C region appear in NOESY spectra,when[Co(phen)2(DPQ)]Cl3 interact with mismatch oligonucleotide d(CCGAATGAGG)2.From the phenomena and the spectra,we have concluded that the complex[Co(phen)2(DPQ)]Cl3 can only interact with d(CCGAATGAGG)2 at terminal G:C region from minor groove.When[Co(phen)2(DPQ)]Cl3 interact with normal oligonucleotide d(CCTAATTAGG)2,lots of intermolecular NOE cross-peaks from [Co(phen)2(DPQ)]Cl3 and the T3/A4 protons.From the phenomena and the spectra,we have concluded that the complex[Co(phen)2(DPQ)]Cl3 can insert into normal oligonucleotide d(CCTAATTAGG)2 in T3/A4 from the minor groove.For the overlap of H4' and H5'/H5" on sugar,we cannot ascribe them syllabify,but NOE cross-peaks indicated that[Co(phen)2 (DPQ)]Cl3 insert into oligonucleotide truly.Moreover,there is a cross-peak of DPQ interaction with T3CH3,which indicated that DPQ system bestride base from minor groove to major groove.31p NMR indicate that [Co(phen)2(HPIP)]Cl3 cannot change the phosphor framework of oligonucleotide.From molecule simulate we can see that [Co(phen)2(DPQ)]Cl3 can interaction with sheared DNA at terminal region from minor groove by L-isomer,and L-isomer will be enriched. [Co(phen)2(DPQ)]Cl3 can interaction with normal DNA at T3A4 region from minor groove by L-isomer,and L-isomer will be enriched.The above results indicate that 2D NMR can consistent with the result of molecular simulate.For[Co(phen)2(HNAIP)]Cl3,a lot of intermolecular NOE cross-peaks from[Co(phen)2(HNAIP)]Cl3 and the sheared G:A region appear in NOESY spectra,and the intensity of the sequential NOE cross-peaks decrease or diminish.From the phenomena and the spectra,we have concluded that the complex[Co(phen)2(HNAIP)]Cl3 can insert into base T6G7 from major groove.Maybe it is because of the size of insertion ligand,no NOE cross-peaks appear in NOESY spectra of normal oligonucleotide d(CCTAATTAGG)2.The reason will be researched in the future. |
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