DNA-dependent DNA and RNA polymerases are important modulators of biological functions such as replication, transcription, recombination, or repair. In this work performed in cell-free media, we studied the ability of selected DNA polymerases to overcome a monofunctional adduct of the cytotoxic/antitumor platinum-acridinylthiourea conjugate [PtCl(en)(L)](NO3)2 (en = ethane-1,2-diamine, L = 1-[2-(acridin-9-ylamino)ethyl]-1,3-dimethylthiourea) (ACR) in its favored 5'-CG sequence. We focused on how a single site-specific ACR adduct with intercalation potency affects the processivity and fidelity of DNA-dependent DNA polymerases involved in translesion synthesis (TLS) and repair. The ability of the G(N7) hybrid ACR adduct formed in the 5'-TCGT sequence of a 24-mer DNA template to inhibit the synthesis of a complementary DNA strand by the exonuclease-deficient Klenow fragment of DNA polymerase I (KFexo-) and human polymerases eta, kappa, and iota was supplemented by thermodynamic analysis of the polymerization process. Thermodynamic parameters of a simulated translesion synthesis across the ACR adduct were obtained by using microscale thermophoresis (MST). Our results show a strong inhibitory effect of an ACR adduct on enzymatic TLS: there was only small synthesis of a full-length product (less than 10%) except polymerase eta (~20%). Polymerase eta was able to most efficiently bypass the ACR hybrid adduct. Incorporation of a correct dCMP opposite the modified G residue is preferred by all the four polymerases tested. On the other hand, the frequency of misinsertions increased. The relative efficiency of misinsertions is higher than that of matched cytidine monophosphate but still lower than for the nonmodified control duplex. Thermodynamic inspection of the simulated TLS revealed a significant stabilization of successively extended primer/template duplexes containing an ACR adduct. Moreover, no significant decrease of dissociation enthalpy change behind the position of the modification can contribute to the enzymatic TLS observed with the DNA-dependent, repair-involved polymerases. This TLS could lead to a higher tolerance of cancer cells to the ACR conjugate compared to its enhanced analog, where thiourea is replaced by an amidine group: [PtCl(en)(L)](NO3)2 (complex AMD, en = ethane-1,2-diamine, L = N-[2-(acridin-9-ylamino)ethyl]-N-methylpropionamidine).

• MeSH
• adukty DNA chemie   MeSH
• DNA-dependentní DNA-polymerasy metabolismus   MeSH
• interkalátory chemie   MeSH
• lidé MeSH
• močovina analogy a deriváty   chemie   MeSH
• oprava DNA * MeSH
• organoplatinové sloučeniny chemie   MeSH
• poškození DNA * MeSH
• replikace DNA MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Translesion synthesis (TLS) through DNA adducts of antitumor platinum complexes has been an interesting aspect of DNA synthesis in cells treated with these metal-based drugs because of its correlation to drug sensitivity. We utilized model systems employing a DNA lesion derived from a site-specific monofunctional adduct formed by antitumor [PtCl(en)(L)](NO3)2 (complex AMD, en = ethane-1,2-diamine, L = N-[2-(acridin-9-ylamino)ethyl]-N-methylpropionamidine) at a unique G residue. The catalytic efficiency of TLS DNA polymerases, which differ in their processivity and fidelity for the insertion of correct dCTP, with respect to the other incorrect nucleotides, opposite the adduct of AMD, was investigated. For a deeper understanding of the factors that control the bypass of the site-specific adducts of AMD catalyzed by DNA polymerases, we also used microscale thermophoresis (MST) to measure the thermodynamic changes associated with TLS across a single, site-specific adduct formed in DNA by AMD. The relative catalytic efficiency of the investigated DNA polymerases for the insertion of correct dCTP, with respect to the other incorrect nucleotides, opposite the AMD adduct, was reduced. Nevertheless, incorporation of the correct C opposite the G modified by AMD of the template strand was promoted by an increasing thermodynamic stability of the resulting duplex. The reduced relative efficiency of the investigated DNA polymerases may be a consequence of the DNA intercalation of the acridine moiety of AMD and the size of the adduct. The products of the bypass of this monofunctional lesion produced by AMD and DNA polymerases also resulted from the misincorporation of dNTPs opposite the platinated G residues. The MST analysis suggested that thermodynamic factors may contribute to the forces that governed enhanced incorporation of the incorrect dNTPs by DNA polymerases.

• MeSH
• adukty DNA chemie   genetika   metabolismus   MeSH
• akridiny chemie   farmakologie   MeSH
• biokatalýza MeSH
• DNA-dependentní DNA-polymerasy metabolismus   MeSH
• DNA biosyntéza   MeSH
• guanin metabolismus   MeSH
• katalýza MeSH
• nukleotidy genetika   metabolismus   MeSH
• oprava DNA MeSH
• replikace DNA MeSH
• sloučeniny platiny chemie   farmakologie   MeSH
• tepelná difuze MeSH
• termodynamika MeSH
• Publikační typ
• časopisecké články MeSH

Polynuclear platinum complexes represent a unique structural class of DNA-binding agents of biological significance. They contain at least two platinum coordinating units bridged by a linker, which means that the formation of double-base lesions (cross-links) in DNA is possible. Here, we show that the lead compound, bifunctional [{trans-PtCl(NH3)2}2μ-trans-Pt(NH3)2{H2N(CH2)6NH2}2]4+ (Triplatin or BBR3464), forms in DNA specific double-base lesions which affect the biophysical and biochemical properties of DNA in a way fundamentally different compared to the analogous double-base lesions formed by two adducts of monofunctional chlorodiethylenetriamineplatinum(ii) chloride (dienPt). We find concomitantly that translesion DNA synthesis by the model A-family polymerase, the exonuclease deficient Klenow fragment, across the double-base lesions derived from the intrastrand CLs of Triplatin was markedly less extensive than that across the two analogous monofunctional adducts of dienPt. Collectively, these data provide convincing support for the hypothesis that the central noncovalent tetraamine platinum linker of Triplatin, capable of hydrogen-bonding and electrostatic interactions with DNA and bridging the two platinum adducts, represents an important factor responsible for the markedly lowered tolerance of DNA double-base adducts of Triplatin by DNA polymerases.

• MeSH
• adukty DNA chemie   metabolismus   MeSH
• antitumorózní látky chemie   metabolismus   MeSH
• DNA-dependentní DNA-polymerasy metabolismus   MeSH
• DNA chemie   metabolismus   MeSH
• kompetitivní vazba MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• organoplatinové sloučeniny chemie   metabolismus   MeSH
• reagencia zkříženě vázaná chemie   metabolismus   MeSH
• termodynamika MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The main mechanism of action of platinum-based cytostatic drugs - cisplatin, oxaliplatin and carboplatin - is the formation of DNA cross-links, which restricts the transcription due to the disability of DNA to enter the active site of the polymerase. The polymerase chain reaction (PCR) was employed as a simplified model of the amplification process in the cell nucleus. PCR with fluorescently labelled dideoxynucleotides commonly employed for DNA sequencing was used to monitor the effect of platinum-based cytostatics on DNA in terms of decrease in labeling efficiency dependent on a presence of the DNA-drug cross-link. It was found that significantly different amounts of the drugs - cisplatin (0.21 μg/mL), oxaliplatin (5.23 μg/mL), and carboplatin (71.11 μg/mL) - were required to cause the same quenching effect (50%) on the fluorescent labelling of 50 μg/mL of DNA. Moreover, it was found that even though the amounts of the drugs was applied to the reaction mixture differing by several orders of magnitude, the amount of incorporated platinum, quantified by inductively coupled plasma mass spectrometry, was in all cases at the level of tenths of μg per 5 μg of DNA.

• MeSH
• adukty DNA chemie   metabolismus   MeSH
• cisplatina chemie   MeSH
• cytostatické látky chemie   MeSH
• DNA analýza   chemie   metabolismus   MeSH
• hmotnostní spektrometrie MeSH
• karboplatina chemie   MeSH
• organoplatinové sloučeniny chemie   MeSH
• platina chemie   MeSH
• polymerázová řetězová reakce MeSH
• sekvenční analýza DNA * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The DNA interstrand cross-links of the antitumor drug {[cis-Pt(NH3)2Cl]2(4,4'-methylenedianiline)}2+(1) play a prevalent role in its antitumor effects. Complex 1 forms DNA long-range interstrand cross-links uniquely in the 3'-3' direction. Conformational distortions induced by these interstrand cross-links in DNA represent a potential structural motif for recognition by high-mobility-group proteins.

• MeSH
• adukty DNA chemie   MeSH
• antitumorózní látky chemie   farmakologie   MeSH
• DNA chemie   MeSH
• interkalátory chemie   farmakologie   MeSH
• konformace nukleové kyseliny účinky léků   MeSH
• lidé MeSH
• organoplatinové sloučeniny chemie   farmakologie   MeSH
• reagencia zkříženě vázaná chemie   farmakologie   MeSH
• sekvence nukleotidů MeSH
• simulace molekulového dockingu MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Nuclear DNA is the target responsible for anticancer activity of platinum anticancer drugs. Their activity is mediated by altered signals related to programmed cell death and the activation of various signaling pathways. An example is activation of nuclear factor kappaB (NF-κB). Binding of NF-κB proteins to their consensus sequences in DNA (κB sites) is the key biochemical activity responsible for the biological functions of NF-κB. Using gel-mobility-shift assays and surface plasmon resonance spectroscopy we examined the interactions of NF-κB proteins with oligodeoxyribonucleotide duplexes containing κB site damaged by DNA adducts of three platinum complexes. These complexes markedly differed in their toxic effects in tumor cells and comprised highly cytotoxic trinuclear platinum(II) complex BBR3464, less cytotoxic conventional cisplatin and ineffective transplatin. The results indicate that structurally different DNA adducts of these platinum complexes exhibit a different efficiency to affect the affinity of the platinated DNA (κB sites) to NF-κB proteins. Our results support the hypothesis that structural perturbations induced in DNA by platinum(II) complexes correlate with their higher efficiency to inhibit binding of NF-κB proteins to their κB sites and cytotoxicity as well. However, the full generalization of this hypothesis will require to evaluate a larger series of platinum(II) complexes.

• MeSH
• adukty DNA chemie   metabolismus   MeSH
• antitumorózní látky chemie   metabolismus   farmakologie   MeSH
• cisplatina chemie   metabolismus   farmakologie   MeSH
• HEK293 buňky MeSH
• kinetika MeSH
• komplexní sloučeniny chemie   metabolismus   farmakologie   MeSH
• konsenzuální sekvence MeSH
• lidé MeSH
• NF-kappa B chemie   genetika   metabolismus   MeSH
• oligodeoxyribonukleotidy chemie   metabolismus   MeSH
• organoplatinové sloučeniny chemie   toxicita   MeSH
• platina chemie   metabolismus   MeSH
• povrchová plasmonová rezonance MeSH
• rekombinantní proteiny biosyntéza   chemie   izolace a purifikace   MeSH
• retardační test MeSH
• termodynamika MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

The moderate-to-high in vitro cytotoxicity against ovarian A2780 (IC50 = 4.7-14.4 μM), prostate LNCaP (IC50 = 18.7-30.8 μM) and prostate PC-3 (IC50 = 17.6-42.3 μM) human cancer cell lines of the platinum(II) cyclobutane-1,1'-dicarboxylato complexes [Pt(cbdc)(naza)2] (1-6; cbdc = cyclobutane-1,1'-dicarboxylate(2-); naza = halogeno-substituted 7-azaindoles), derived from the anticancer metallodrug carboplatin, are reported. The complexes containing the chloro- and bromo-substituted 7-azaindoles (1, 2, and 4-6) showed a significantly higher (p < 0.05) cytotoxicity against A2780 cell line as compared to cisplatin used as a reference drug. Addition of the non-toxic concentration (5.0 μM) of L-buthionine sulfoximine (L-BSO, an effective inhibitor of γ-glutamylcysteine synthase) markedly increases the in vitro cytotoxicity of the selected complex 3 against A2780 cancer cell line by a factor of about 4.4. The cytotoxicity against A2780 and LNCaP cells, as well as the DNA platination, were effectively enhanced by UVA light irradiation (λmax = 365 nm) of the complexes, with the highest phototoxicity determined for compound 3, resulting in a 4-fold decline in the A2780 cells viability from 25.1% to 6.1%. The 1H NMR and ESI-MS experiments suggested that the complexes did not interact with glutathione as well as their ability to interact with guanosine monophosphate. The studies also confirmed UVA light induced the formation of the cis [Pt(H2O)2(cbdc`)(naza)] intermediate, where cbdc` represents monodentate-coordinated cbdc ligand, which is thought to be responsible for the enhanced cytotoxicity. This is further supported by the results of transcription mapping experiments showing that the studied complexes preferentially form the bifunctional adducts with DNA under UVA irradiation, in contrast to the formation of the less effective monofunctional adducts in dark.

• MeSH
• adukty DNA chemie   genetika   MeSH
• antitumorózní látky chemie   farmakologie   MeSH
• buthionin sulfoximin farmakologie   MeSH
• dvouřetězcové zlomy DNA účinky léků   účinky záření   MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• indoly chemie   farmakologie   MeSH
• karboplatina chemie   farmakologie   MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• molekulární struktura MeSH
• nádorové buněčné linie MeSH
• nádory genetika   patologie   MeSH
• protonová magnetická rezonanční spektroskopie MeSH
• synergismus léků MeSH
• ultrafialové záření * MeSH
• viabilita buněk účinky léků   genetika   účinky záření   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

This study quantified the temporal variability of concentration of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs), genotoxicity, oxidative DNA damage and dioxin-like activity of the extractable organic matter (EOM) of atmospheric aerosol particles of aerodynamic diameter (dae, μm) coarse (1 < dae < 10), upper- (0.5 < dae < 1) and lower-accumulation (0.17 < dae < 0.5) and ultrafine (<0.17) fractions. The upper accumulation fraction formed most of the aerosol mass for 22 of the 26 study days and contained ∼44% of total c-PAHs, while the ultrafine fraction contained only ∼11%. DNA adduct levels suggested a crucial contribution of c-PAHs bound to the upper accumulation fraction. The dioxin-like activity was also driven primarily by c-PAH concentrations. In contrast, oxidative DNA damage was not related to c-PAHs, as a negative correlation with c-PAHs was observed. These results suggest that genotoxicity and dioxin-like activity are the major toxic effects of organic compounds bound to size segregated aerosol, while oxidative DNA damage is not induced by EOM.

• MeSH
• adukty DNA analýza   chemie   MeSH
• aerosoly MeSH
• DNA chemie   MeSH
• látky znečišťující vzduch analýza   toxicita   MeSH
• monitorování životního prostředí metody   MeSH
• oxidace-redukce MeSH
• pevné částice analýza   toxicita   MeSH
• polycyklické aromatické uhlovodíky analýza   toxicita   MeSH
• velikost částic MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The requirements for early diagnostics as well as effective treatment of cancer diseases have increased the pressure on development of efficient methods for targeted drug delivery as well as imaging of the treatment success. One of the most recent approaches covering the drug delivery aspects is benefitting from the unique properties of nanomaterials. Ellipticine and its derivatives are efficient anticancer compounds that function through multiple mechanisms. Formation of covalent DNA adducts after ellipticine enzymatic activation is one of the most important mechanisms of its pharmacological action. In this study, we investigated whether ellipticine might be released from its micellar (encapsulated) form to generate covalent adducts analogous to those formed by free ellipticine. The (32)P-postlabeling technique was used as a useful imaging method to detect and quantify covalent ellipticine-derived DNA adducts. We compared the efficiencies of free ellipticine and its micellar form (the poly(ethylene oxide)-block-poly(allyl glycidyl ether) (PAGE-PEO) block copolymer, P 119 nanoparticles) to form ellipticine-DNA adducts in rats in vivo. Here, we demonstrate for the first time that treatment of rats with ellipticine in micelles resulted in formation of ellipticine-derived DNA adducts in vivo and suggest that a gradual release of ellipticine from its micellar form might produce the enhanced permeation and retention effect of this ellipticine-micellar delivery system.

• MeSH
• adukty DNA chemie   metabolismus   MeSH
• antitumorózní látky aplikace a dávkování   chemie   farmakokinetika   MeSH
• elipticiny aplikace a dávkování   chemie   farmakokinetika   MeSH
• krysa rodu rattus MeSH
• metabolická clearance MeSH
• micely MeSH
• orgánová specificita MeSH
• potkani Wistar MeSH
• příprava léků metody   MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The anti-tumor therapeutic ellipticine and its derivatives act as potent anticancer agents via a combined mechanism involving cell cycle arrest and induction of apoptosis. Cell death induced by ellipticine has been shown to engage a p53-dependent pathway, cell cycle arrest, interaction with several kinases and induction of the mitochondrial pathway of apoptotic cell death. Cell cycle arrest was shown to result from DNA damage caused by a variety of tumor chemotherapeutic agents; this is also the case for ellipticines. The prevalent DNA-mediated mechanisms of anti-tumor, mutagenic and cytotoxic activities of ellipticine are (i) intercalation into DNA, (ii) inhibition of DNA topoisomerase II activity, and (iii) covalent binding to DNA in vitro and in vivo after enzymatic activation by cytochrome P450 and/or peroxidase enzymes The mechanism leading to apoptosis by ellipticine is thought to also be associated with DNA damage, by inhibition of topoisomerase II and the covalent modification of DNA. In addition, the formation of ellipticine-DNA adducts ultimately can mutate cancer cells or initiate cell death. The aim of this review is to summarize our knowledge on the molecular mechanisms with the aim to explain the effectiveness of ellipticines as DNA-targeted chemotherapeutics in cancer cells.

• MeSH
• adukty DNA chemie   metabolismus   MeSH
• antitumorózní látky chemie   farmakologie   terapeutické užití   MeSH
• apoptóza účinky léků   MeSH
• DNA-topoisomerasy typu II chemie   metabolismus   MeSH
• DNA chemie   metabolismus   MeSH
• elipticiny chemie   farmakologie   terapeutické užití   MeSH
• lidé MeSH
• nádory farmakoterapie   MeSH
• poškození DNA účinky léků   MeSH
• systém (enzymů) cytochromů P-450 metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH