Three potential anticancer agents {trans-[PtCl(2)(NH(3))(thiazole)], cis-[PtCl(2)(NH(3))(piperidine)], and PtCl(2)(NH(3))(cyclohexylamine) (JM118)} were explored and compared with cisplatin and the inactive [PtCl(dien)](+) complex. Basic electronic properties, bonding and stabilization energies were determined, and thermodynamic and kinetic parameters for the aquation reaction were estimated at the B3LYP/6-311++G(2df,2pd) level of theory. Since the aquation process represents activation of these agents, the obtained rate constants were compared with the experimental IC(50) values for several tumor cells. Despite the fact that the processes in which these drugs are involved and the way in which they affect cells are very complex, some correlations can be deduced.

• MeSH
• chemické modely * MeSH
• cisplatina chemie   farmakologie   MeSH
• elektrony MeSH
• inhibiční koncentrace 50 MeSH
• kinetika MeSH
• lidé MeSH
• ligandy MeSH
• nádorové buněčné linie MeSH
• organoplatinové sloučeniny chemie   farmakologie   MeSH
• počítačová simulace * MeSH
• protinádorové látky chemie   farmakologie   MeSH
• sloučeniny platiny chemie   MeSH
• termodynamika MeSH
• thiazoly chemie   farmakologie   MeSH
• voda chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• amminedichloro(cyclohexylamine)platinum(II) MeSH Prohlížeč
• cisplatina MeSH
• ligandy MeSH
• organoplatinové sloučeniny MeSH
• platinum chloride MeSH Prohlížeč
• protinádorové látky MeSH
• sloučeniny platiny MeSH
• thiazoly MeSH
• trans-(PtCl2(NH3)(thiazole)) MeSH Prohlížeč
• voda MeSH

Downstream processes that discriminate between DNA adducts of a third generation platinum antitumor drug oxaliplatin and conventional cisplatin are believed to be responsible for the differences in their biological effects. These different biological effects are explained by the ability of oxaliplatin to form DNA adducts more efficient in their biological effects. In this work conformation, recognition by HMG domain protein and DNA polymerization across the major 1,2-GG intrastrand cross-link formed by cisplatin and oxaliplatin in three sequence contexts were compared with the aid of biophysical and biochemical methods. The following major differences in the properties of the cross-links of oxaliplatin and cisplatin were found: i), the formation of the cross-link by oxaliplatin is more deleterious energetically in all three sequence contexts; ii), the cross-link of oxaliplatin bends DNA slightly but systematically less in all sequence contexts tested; iii), the affinity of HMG domain protein to the cross-link of oxaliplatin is considerably lower independent of the sequence context; and iv), the Klenow fragment of DNA polymerase I pauses considerably more at the cross-link of oxaliplatin in all sequence contexts tested. We have also demonstrated that the chirality at the carrier ligand of oxaliplatin can affect its biological effects.

• MeSH
• adukty DNA chemie   ultrastruktura   MeSH
• guanin chemie   MeSH
• konformace nukleové kyseliny MeSH
• organoplatinové sloučeniny chemie   MeSH
• oxaliplatin MeSH
• párování bází MeSH
• protinádorové látky chemie   MeSH
• reagencia zkříženě vázaná MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adukty DNA MeSH
• guanin MeSH
• organoplatinové sloučeniny MeSH
• oxaliplatin MeSH
• protinádorové látky MeSH
• reagencia zkříženě vázaná MeSH

DNA-protein cross-links are formed by various DNA-damaging agents including antitumor platinum drugs. The natures of these ternary DNA-Pt-protein complexes (DPCLs) can be inferred, yet much remains to be learned about their structures and mechanisms of formation. We investigated the origin of these DPCLs and their cellular processing on molecular level using gel electrophoresis shift assay. We show that in cell-free media cisplatin [cis-diamminedichloridoplatinum(II)] forms DPCLs more effectively than ineffective transplatin [trans-diamminedichloridoplatinum(II)]. Mechanisms of transformation of individual types of plain DNA adducts of the platinum complexes into the DPCLs in the presence of several DNA-binding proteins have been also investigated. The DPCLs are formed by the transformation of DNA monofunctional and intrastrand cross-links of cisplatin. In contrast, interstrand cross-links of cisplatin and monofunctional adducts of transplatin are stable in presence of the proteins. The DPCLs formed by cisplatin inhibit DNA polymerization or removal of these ternary lesions from DNA by nucleotide excision repair system more effectively than plain DNA intrastrand or monofunctional adducts. Thus, the bulky DNA-protein cross-links formed by cisplatin represent a more distinct and persisting structural motif recognized by the components of downstream cellular systems processing DNA damage considerably differently than the plain DNA adducts of this metallodrug.

• MeSH
• adukty DNA chemie   MeSH
• cisplatina chemie   toxicita   MeSH
• DNA vazebné proteiny účinky léků   MeSH
• DNA biosyntéza   účinky léků   MeSH
• oprava DNA MeSH
• protinádorové látky chemie   toxicita   MeSH
• reagencia zkříženě vázaná chemie   toxicita   MeSH
• retardační test MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adukty DNA MeSH
• cisplatin-DNA adduct MeSH Prohlížeč
• cisplatina MeSH
• DNA vazebné proteiny MeSH
• DNA MeSH
• protinádorové látky MeSH
• reagencia zkříženě vázaná MeSH
• transplatin MeSH Prohlížeč

In this study, various platinum cross-links in DNA bases were explored. Some of these structures occur in many cis/trans-platinated double-helixes or single-stranded adducts. However, in the models studied, no steric hindrance from sugar-phosphate backbone or other surroundings is considered. Such restrictions can change the bonding picture partially but hopefully the basic energy characteristics will not be changed substantially. The optimization of the structures explored was performed at the DFT level with the B3LYP functional and the 6-31G(d) basis set. Perturbation theory at the MP2/6-31++G(2df,2pd) level was used for the single-point energy and 6-31+G(d) basis set for the electron-property analyses. It was found that the most stable structures are the diguanine complexes followed by guanine-cytosine Pt-cross-links, ca 5 kcal mol(-1) less stable. The adenine-containing complexes are about 15 kcal mol(-1) below the stability of diguanine structures. This stability order was also confirmed by the BE of Pt-N bonds. For a detailed view on dative and electrostatic contributions to Pt-N bonds, Natural Population Analysis, determination of electrostatic potentials, and canonical Molecular Orbitals description of the examined systems were used.

• MeSH
• adenin chemie   MeSH
• cisplatina chemie   MeSH
• cytosin chemie   MeSH
• guanin chemie   MeSH
• heteroduplexy nukleové kyseliny chemie   MeSH
• jednovláknová DNA chemie   MeSH
• molekulární modely MeSH
• platina chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenin MeSH
• cisplatina MeSH
• cytosin MeSH
• guanin MeSH
• heteroduplexy nukleové kyseliny MeSH
• jednovláknová DNA MeSH
• platina MeSH