Balkan endemic nephropathy is a chronic tubulointerstitial disease with insidious onset, slowly progressing to end-stage renal disease and frequently associated with urothelial carcinoma of the upper urinary tract (UTUC). It was described in South-East Europe at the Balkan peninsula in rural areas around tributaries of the Danube River. After decades of intensive investigation, the causative factor was identified as the environmental phytotoxin aristolochic acid (AA) contained in Aristolochia clematitis, a common plant growing in wheat fields that was ingested through home-baked bread. AA initially was involved in the outbreak of cases of rapidly progressive renal fibrosis reported in Belgium after intake of root extracts of Aristolochia fangchi imported from China. A high prevalence of UTUC was found in these patients. The common molecular link between Balkan and Belgian nephropathy cases was the detection of aristolactam-DNA adducts in renal tissue and UTUC. These adducts are not only biomarkers of prior exposure to AA, but they also trigger urothelial malignancy by inducing specific mutations (A:T to T:A transversion) in critical genes of carcinogenesis, including the tumor-suppressor TP53. Such mutational signatures are found in other cases worldwide, particularly in Taiwan, highlighting the general public health issue of AA exposure by traditional phytotherapies.

• Klíčová slova
• Aristolochia species, Balkan endemic nephropathy, aristolochic acid, aristolochic acid nephropathy, upper tract urothelial carcinoma,
• MeSH
• adukty DNA MeSH
• Aristolochia MeSH
• balkánská nefropatie chemicky indukované   diagnóza   patologie   terapie   MeSH
• karcinogeny toxicita   MeSH
• karcinom z přechodných buněk chemicky indukované   MeSH
• kyseliny aristolochové toxicita   MeSH
• lidé MeSH
• nádory ledvin chemicky indukované   MeSH
• nádory močovodu chemicky indukované   MeSH
• plošný screening MeSH
• vystavení vlivu životního prostředí škodlivé účinky   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• adukty DNA MeSH
• aristolochic acid I MeSH Prohlížeč
• karcinogeny MeSH
• kyseliny aristolochové MeSH

Although ellipticine (Elli) is an efficient anticancer agent, it exerts several adverse effects. One approach to decrease the adverse effects of drugs is their encapsulation inside a suitable nanocarrier, allowing targeted delivery to tumour tissue whereas avoiding healthy cells. We constructed a nanocarrier from apoferritin (Apo) bearing ellipticine, ApoElli, and subsequently characterized. The nanocarrier exhibits a narrow size distribution suggesting its suitability for entrapping the hydrophobic ellipticine molecule. Ellipticine was released from ApoElli into the water environment under pH 6.5, but only less than 20% was released at pH 7.4. The interaction of ApoElli with microsomal membrane particles containing cytochrome P450 (CYP) biotransformation enzymes accelerated the release of ellipticine from this nanocarrier making it possible to be transferred into this membrane system even at pH 7.4 and facilitating CYP-mediated metabolism. Reactive metabolites were formed not only from free ellipticine, but also from ApoElli, and both generated covalent DNA adducts. ApoElli was toxic in UKF-NB-4 neuroblastoma cells, but showed significantly lower cytotoxicity in non-malignant fibroblast HDFn cells. Ellipticine either free or released from ApoElli was concentrated in the nuclei of neuroblastoma cells, concentrations of which being significantly higher in nuclei of UKF-NB-4 than in HDFn cells. In HDFn the higher amounts of ellipticine were sequestrated in lysosomes. The extent of ApoElli entering the nuclei in UKF-NB-4 cells was lower than that of free ellipticine and correlated with the formation of ellipticine-derived DNA adducts. Our study indicates that the ApoElli form of ellipticine seems to be a promising tool for neuroblastoma treatment.

• Klíčová slova
• Apoferritin nanoparticles, Cytochrome P450-mediated metabolism, Cytotoxicity, DNA adducts, Ellipticine, Neuroblastoma,
• MeSH
• adukty DNA genetika   metabolismus   MeSH
• apoferritiny chemie   farmakologie   MeSH
• cytochrom P-450 CYP3A metabolismus   MeSH
• elipticiny chemie   farmakologie   MeSH
• fosforylace MeSH
• histony metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nanočástice * MeSH
• neuroblastom farmakoterapie   enzymologie   genetika   patologie   MeSH
• nosiče léků * MeSH
• příprava léků MeSH
• protinádorové látky chemie   farmakologie   MeSH
• uvolňování léčiv MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adukty DNA MeSH
• apoferritiny MeSH
• CYP3A4 protein, human MeSH Prohlížeč
• cytochrom P-450 CYP3A MeSH
• elipticiny MeSH
• ellipticine MeSH Prohlížeč
• H2AX protein, human MeSH Prohlížeč
• histony MeSH
• nosiče léků * MeSH
• protinádorové látky MeSH

Endocrine disruptors (EDs) are compounds that interfere with the balance of the endocrine system by mimicking or antagonising the effects of endogenous hormones, by altering the synthesis and metabolism of natural hormones, or by modifying hormone receptor levels. The synthetic estrogen 17α-ethinylestradiol (EE2) and the environmental carcinogen benzo[a]pyrene (BaP) are exogenous EDs whereas the estrogenic hormone 17β-estradiol is a natural endogenous ED. Although the biological effects of these individual EDs have partially been studied previously, their toxicity when acting in combination has not yet been investigated. Here we treated Wistar rats with BaP, EE2 and estradiol alone or in combination and studied the influence of EE2 and estradiol on: (i) the expression of cytochrome P450 (CYP) 1A1 and 1B1 in rat liver on the transcriptional and translational levels; (ii) the inducibility of these CYP enzymes by BaP in this rat organ; (iii) the formation of BaP-DNA adducts in rat liver in vivo; and (iv) the generation of BaP-induced DNA adducts after activation of BaP with hepatic microsomes of rats exposed to BaP, EE2 and estradiol and with recombinant rat CYP1A1 in vitro. BaP acted as a strong and moderate inducer of CYP1A1 and 1B1 in rat liver, respectively, whereas EE2 or estradiol alone had no effect on the expression of these enzymes. However, when EE2 was administered to rats together with BaP, it significantly decreased the potency of BaP to induce CYP1A1 and 1B1 gene expression. For EE2, but not estradiol, this also correlated with a reduction of BaP-induced CYP1A1 enzyme activity in rat hepatic microsomes. Further, while EE2 and estradiol did not form covalent adducts with DNA, they affected BaP-derived DNA adduct formations in vivo and in vitro. The observed decrease in BaP-DNA adduct levels in rat liver in vivo resulted from the inhibition of CYP1A1-mediated BaP bioactivation by EE2 and estradiol. Our results indicate that BaP genotoxicity mediated through its activation by CYP1A1 in rats in vivo is modulated by estradiol and its synthetic derivative EE2.

• Klíčová slova
• 17alpha-ethinylestradiol, Benzo[a]pyrene, Cytochrome P450, DNA-adducts, Endocrine disruptors, Estradiol,
• MeSH
• benzopyren toxicita   MeSH
• cytochrom P-450 CYP1A1 biosyntéza   genetika   MeSH
• endokrinní disruptory toxicita   MeSH
• estradiol toxicita   MeSH
• ethinylestradiol toxicita   MeSH
• jaterní mikrozomy účinky léků   enzymologie   MeSH
• krysa rodu Rattus MeSH
• potkani Wistar MeSH
• regulace genové exprese enzymů * účinky léků   MeSH
• synergismus léků MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• benzopyren MeSH
• cytochrom P-450 CYP1A1 MeSH
• endokrinní disruptory MeSH
• estradiol MeSH
• ethinylestradiol MeSH

Extra-hepatic metabolism of xenobiotics by epithelial tissues has evolved as a self-defence mechanism but has potential to contribute to the local activation of carcinogens. Bladder epithelium (urothelium) is bathed in excreted urinary toxicants and pro-carcinogens. This study reveals how differentiation affects cytochrome P450 (CYP) activity and the role of NADPH:P450 oxidoreductase (POR). CYP1A1 and CYP1B1 transcripts were inducible in normal human urothelial (NHU) cells maintained in both undifferentiated and functional barrier-forming differentiated states in vitro. However, ethoxyresorufin O-deethylation (EROD) activity, the generation of reactive BaP metabolites and BaP-DNA adducts, were predominantly detected in differentiated NHU cell cultures. This gain-of-function was attributable to the expression of POR, an essential electron donor for all CYPs, which was significantly upregulated as part of urothelial differentiation. Immunohistology of muscle-invasive bladder cancer (MIBC) revealed significant overall suppression of POR expression. Stratification of MIBC biopsies into "luminal" and "basal" groups, based on GATA3 and cytokeratin 5/6 labeling, showed POR over-expression by a subgroup of the differentiated luminal tumors. In bladder cancer cell lines, CYP1-activity was undetectable/low in basal PORlo T24 and SCaBER cells and higher in the luminal POR over-expressing RT4 and RT112 cells than in differentiated NHU cells, indicating that CYP-function is related to differentiation status in bladder cancers. This study establishes POR as a predictive biomarker of metabolic potential. This has implications in bladder carcinogenesis for the hepatic versus local activation of carcinogens and as a functional predictor of the potential for MIBC to respond to prodrug therapies.

• Klíčová slova
• CPR, CYP1A1, POR, aryl hydrocarbon receptor, urothelium,
• MeSH
• buněčná diferenciace MeSH
• čipová analýza tkání MeSH
• cytochrom P-450 CYP1A1 genetika   MeSH
• cytochrom P450 CYP1B1 genetika   MeSH
• down regulace MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádory močového měchýře genetika   metabolismus   MeSH
• regulace genové exprese u nádorů MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• systém (enzymů) cytochromů P-450 metabolismus   MeSH
• urotel cytologie   metabolismus   MeSH
• xenobiotika farmakologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CYP1A1 protein, human MeSH Prohlížeč
• CYP1B1 protein, human MeSH Prohlížeč
• cytochrom P-450 CYP1A1 MeSH
• cytochrom P450 CYP1B1 MeSH
• POR protein, human MeSH Prohlížeč
• systém (enzymů) cytochromů P-450 MeSH
• xenobiotika MeSH

Polycyclic aromatic hydrocarbons such as benzo[a]pyrene (BaP) can induce cytochrome P450 1A1 (CYP1A1) via a p53-dependent mechanism. The effect of different p53-activating chemotherapeutic drugs on CYP1A1 expression, and the resultant effect on BaP metabolism, was investigated in a panel of isogenic human colorectal HCT116 cells with differing TP53 status. Cells that were TP53(+/+), TP53(+/-) or TP53(-/-) were treated for up to 48 h with 60 μM cisplatin, 50 μM etoposide or 5 μM ellipticine, each of which caused high p53 induction at moderate cytotoxicity (60-80% cell viability). We found that etoposide and ellipticine induced CYP1A1 in TP53(+/+) cells but not in TP53(-/-) cells, demonstrating that the mechanism of CYP1A1 induction is p53-dependent; cisplatin had no such effect. Co-incubation experiments with the drugs and 2.5 μM BaP showed that: (i) etoposide increased CYP1A1 expression in TP53(+/+) cells, and to a lesser extent in TP53(-/-) cells, compared to cells treated with BaP alone; (ii) ellipticine decreased CYP1A1 expression in TP53(+/+) cells in BaP co-incubations; and (iii) cisplatin did not affect BaP-mediated CYP1A1 expression. Further, whereas cisplatin and etoposide had virtually no influence on CYP1A1-catalysed BaP metabolism, ellipticine treatment strongly inhibited BaP bioactivation. Our results indicate that the underlying mechanisms whereby etoposide and ellipticine regulate CYP1A1 expression must be different and may not be linked to p53 activation alone. These results could be relevant for smokers, who are exposed to increased levels of BaP, when prescribing chemotherapeutic drugs. Beside gene-environment interactions, more considerations should be given to potential drug-environment interactions during chemotherapy.

• Klíčová slova
• Benzo[a]pyrene, Cisplatin, Cytochrome P450, Ellipticine, Etoposide, Tumour suppressor p53,
• MeSH
• adukty DNA metabolismus   MeSH
• benzopyren farmakokinetika   farmakologie   MeSH
• cisplatina farmakologie   MeSH
• cytochrom P-450 CYP1A1 biosyntéza   metabolismus   MeSH
• cytochrom P-450 CYP3A biosyntéza   metabolismus   MeSH
• elipticiny farmakokinetika   farmakologie   MeSH
• enzymová indukce účinky léků   MeSH
• etoposid farmakologie   MeSH
• geny p53 MeSH
• HCT116 buňky MeSH
• karcinogeny farmakokinetika   farmakologie   MeSH
• kolorektální nádory farmakoterapie   genetika   metabolismus   patologie   MeSH
• lidé MeSH
• metabolická aktivace MeSH
• nádorový supresorový protein p53 nedostatek   genetika   metabolismus   MeSH
• poškození DNA MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adukty DNA MeSH
• benzopyren MeSH
• cisplatina MeSH
• CYP1A1 protein, human MeSH Prohlížeč
• CYP3A4 protein, human MeSH Prohlížeč
• cytochrom P-450 CYP1A1 MeSH
• cytochrom P-450 CYP3A MeSH
• elipticiny MeSH
• ellipticine MeSH Prohlížeč
• etoposid MeSH
• karcinogeny MeSH
• nádorový supresorový protein p53 MeSH
• TP53 protein, human MeSH Prohlížeč

Benzo[a]pyrene (BaP) is an environmental pollutant that, based on evidence largely from in vitro studies, exerts its genotoxic effects after metabolic activation by cytochrome P450s. In the present study, Hepatic Reductase Null (HRN) and Hepatic Cytochrome b 5 /P450 Reductase Null (HBRN) mice have been used to study the role of P450s in the metabolic activation of BaP in vivo. In HRN mice, cytochrome P450 oxidoreductase (POR), the electron donor to P450, is deleted specifically in hepatocytes. In HBRN mice the microsomal haemoprotein cytochrome b 5 , which can also act as an electron donor from cytochrome b 5 reductase to P450s, is also deleted in the liver. Wild-type (WT), HRN and HBRN mice were treated by i.p. injection with 125 mg/kg body weight BaP for 24 h. Hepatic microsomal fractions were isolated from BaP-treated and untreated mice. In vitro incubations carried out with BaP-pretreated microsomal fractions, BaP and DNA resulted in significantly higher BaP-DNA adduct formation with WT microsomal fractions compared to those from HRN or HBRN mice. Adduct formation (i.e. 10-(deoxyguanosin-N2-yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydro-BaP [dG-N2-BPDE]) correlated with observed CYP1A activity and metabolite formation (i.e. BaP-7,8-dihydrodiol) when NADPH or NADH was used as enzymatic cofactors. BaP-DNA adduct levels (i.e. dG-N2-BPDE) in vivo were significantly higher (~ sevenfold) in liver of HRN mice than WT mice while no significant difference in adduct formation was observed in liver between HBRN and WT mice. Our results demonstrate that POR and cytochrome b 5 both modulate P450-mediated activation of BaP in vitro. However, hepatic P450 enzymes in vivo appear to be more important for BaP detoxification than its activation.

• MeSH
• adukty DNA metabolismus   MeSH
• benzopyren metabolismus   MeSH
• cytochrom-B(5)-reduktasa metabolismus   MeSH
• hepatocyty enzymologie   MeSH
• jaterní mikrozomy enzymologie   MeSH
• myši knockoutované MeSH
• myši MeSH
• NADPH-cytochrom c-reduktasa metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adukty DNA MeSH
• benzo(a)pyrene-DNA adduct MeSH Prohlížeč
• benzopyren MeSH
• cytochrom-B(5)-reduktasa MeSH
• NADPH-cytochrom c-reduktasa MeSH

Benzo[a]pyrene (BaP) is a human carcinogen that covalently binds to DNA after activation by cytochrome P450 (P450). Here, we investigated whether NADH:cytochrome b5 reductase (CBR) in the presence of cytochrome b5 can act as sole electron donor to human P450 1A1 during BaP oxidation and replace the canonical NADPH:cytochrome P450 reductase (POR) system. We also studied the efficiencies of the coenzymes of these reductases, NADPH as a coenzyme of POR, and NADH as a coenzyme of CBR, to mediate BaP oxidation. Two systems containing human P450 1A1 were utilized: human recombinant P450 1A1 expressed with POR, CBR, epoxide hydrolase, and cytochrome b5 in Supersomes and human recombinant P450 1A1 reconstituted with POR and/or with CBR and cytochrome b5 in liposomes. BaP-9,10-dihydrodiol, BaP-7,8-dihydrodiol, BaP-1,6-dione, BaP-3,6-dione, BaP-9-ol, BaP-3-ol, a metabolite of unknown structure, and two BaP-DNA adducts were generated by the P450 1A1-Supersomes system, both in the presence of NADPH and in the presence of NADH. The major BaP-DNA adduct detected by (32)P-postlabeling was characterized as 10-(deoxyguanosin-N(2)-yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydro-BaP (assigned adduct 1), while the minor adduct is probably a guanine adduct derived from 9-hydroxy-BaP-4,5-epoxide (assigned adduct 2). BaP-3-ol as the major metabolite, BaP-9-ol, BaP-1,6-dione, BaP-3,6-dione, an unknown metabolite, and adduct 2 were observed in the system using P450 1A1 reconstituted with POR plus NADPH. When P450 1A1 was reconstituted with CBR and cytochrome b5 plus NADH, BaP-3-ol was the predominant metabolite too, and an adduct 2 was also generated. Our results demonstrate that the NADH/cytochrome b5/CBR system can act as the sole electron donor both for the first and second reduction of P450 1A1 during the oxidation of BaP in vitro. They suggest that NADH-dependent CBR can replace NADPH-dependent POR in the P450 1A1-catalyzed metabolism of BaP.

• MeSH
• adukty DNA metabolismus   MeSH
• benzopyren toxicita   MeSH
• cytochrom-B(5)-reduktasa metabolismus   MeSH
• lidé MeSH
• oxidace-redukce MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adukty DNA MeSH
• benzopyren MeSH
• cytochrom-B(5)-reduktasa MeSH

The tumour suppressor p53 is one of the most important cancer genes. Previous findings have shown that p53 expression can influence DNA adduct formation of the environmental carcinogen benzo[a]pyrene (BaP) in human cells, indicating a role for p53 in the cytochrome P450 (CYP) 1A1-mediated biotransformation of BaP in vitro. We investigated the potential role of p53 in xenobiotic metabolism in vivo by treating Trp53(+/+), Trp53(+/-) and Trp53(-/-) mice with BaP. BaP-DNA adduct levels, as measured by (32)P-postlabelling analysis, were significantly higher in liver and kidney of Trp53(-/-) mice than of Trp53(+/+) mice. Complementarily, significantly higher amounts of BaP metabolites were also formed ex vivo in hepatic microsomes from BaP-pretreated Trp53(-/-) mice. Bypass of the need for metabolic activation by treating mice with BaP-7,8-dihydrodiol-9,10-epoxide resulted in similar adduct levels in liver and kidney in all mouse lines, confirming that the influence of p53 is on the biotransformation of the parent compound. Higher BaP-DNA adduct levels in the livers of Trp53(-/-) mice correlated with higher CYP1A protein levels and increased CYP1A enzyme activity in these animals. Our study demonstrates a role for p53 in the metabolism of BaP in vivo, confirming previous in vitro results on a novel role for p53 in CYP1A1-mediated BaP metabolism. However, our results also suggest that the mechanisms involved in the altered expression and activity of the CYP1A1 enzyme by p53 in vitro and in vivo are different.

• Klíčová slova
• Benzo[a]pyrene, Carcinogen metabolism, Cytochrome P450, DNA adducts, Mouse models, Tumour suppressor p53,
• MeSH
• adukty DNA metabolismus   MeSH
• benzopyren metabolismus   farmakokinetika   MeSH
• cytochrom P-450 CYP1A1 metabolismus   MeSH
• jaterní mikrozomy účinky léků   metabolismus   MeSH
• karcinogeny životního prostředí metabolismus   farmakokinetika   MeSH
• ledviny účinky léků   metabolismus   MeSH
• metabolická aktivace MeSH
• metabolická inaktivace MeSH
• mutantní kmeny myší MeSH
• myši inbrední C57BL MeSH
• NAD(P)H dehydrogenasa (chinon) metabolismus   MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• poškození DNA účinky léků   genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adukty DNA MeSH
• benzo(a)pyrene-DNA adduct MeSH Prohlížeč
• benzopyren MeSH
• cytochrom P-450 CYP1A1 MeSH
• karcinogeny životního prostředí MeSH
• NAD(P)H dehydrogenasa (chinon) MeSH
• nádorový supresorový protein p53 MeSH
• Nqo1 protein, mouse MeSH Prohlížeč