WorldWideScience

Sample records for 3-methylcholanthrene

  1. Effect of interleukin 12 on tumor induction by 3-methylcholanthrene.

    Noguchi, Y; Jungbluth, A; Richards, E C; Old, L J

    1996-01-01

    Interleukin (IL)-12 has strong antitumor activity in transplantable tumor systems in the mouse. The present study was designed to determine whether tumor induction by 3-methylcholanthrene (3-MC), a carcinogenic hydrocarbon, can be inhibited by IL-12. BALB/cBy mice were injected subcutaneously with 25 micrograms or 100 micrograms of 3-MC and treated with 100 ng, 10 ng, or 1 ng of IL-12 for 5 days a week for 18 weeks, with a schedule of 3 weeks on and 1 week off. In mice injected with 25 microg...

  2. Prevention of 3-methylcholanthrene-induced fibrosarcomas in rats pre-inoculated with endogenous rat retrovirus.

    Fish, D C; Demarais, J T; Djurickovic, D B; Huebner, R J

    1981-01-01

    Weanling Fischer 344 rats received a single intraperitoneal injection of a 1000-fold concentrated preparation of endogenous nontransforming rat retrovirus. Ten days later, the rats were each given a single subcutaneous injection of 3-methylcholanthrene. The rats inoculated with the endogenous rat retrovirus were significantly protected against the development of cancer, whereas uninoculated rats and rats given one of several murine retroviruses or baboon retrovirus were not protected.

  3. The effect of 3-methylcholanthrene and butylated hydroxytoluene on glycogen levels of liver, muscle, testis, and tumor tissues of rats

    POLAT, Fikriye; DERE, Egemen; GÜL, Eylem; YELKUVAN, İzzet; ÖZDEMİR, Öztürk; BİNGÖL, Günsel

    2013-01-01

    This study examined the effects of separate and combined applications of 3-methylcholanthrene, a polycyclic aromatic hydrocarbon and potent carcinogenic agent, and butylated hydroxytoluene, the antioxidant food additive, on the glycogen levels of liver, muscle, testis, and tumor tissues in rats. Adult male Wistar albino rats weighing 100-110 g at 8 weeks of age were used in this study. This study consisted of a control group (n = 9) and 3 different experiment groups in which rats were chronic...

  4. Analysis of Ki-ras Exon 2 Gene Mutations in 3-Methylcholanthrene and Butylated Hydroxytoluene-Induced Rat Lung Tissues

    POLAT, Fikriye; ÖZDEMİR, Öztürk; ELAGÖZ, Şahende

    2008-01-01

    3-Methylcholanthrene (MCA) is a polycyclic aromatic hydrocarbon and potent carcinogenic agent that is often used in experimental cancer studies. Butylated hydroxytoluene (BHT) has been widely used for many years as an antioxidant to preserve and stabilize the freshness, nutritional value, flavor, and color of foods. The aim of the present study was to investigate the role of the application of MCA and BHT in the development of lung cancer, and to detect any mutation in the Ki-ras gene exon 2....

  5. Influences of 3-methylcholanthrene, phenobarbital and dexamethasone on xenobiotic metabolizing-related cytochrome P450 enzymes and steroidogenesis in human fetal adrenal cortical cells

    Hui WANG; Min HUANG; Ren-xiu PENG; Jiang LE

    2006-01-01

    Aim: To explore the influence and possible mechanism of xenobiotics on adrenal steroidogenesis during fetal development. Methods: Primary human fetal adrenal cortical cells were prepared, cultured and treated with 3-methylcholanthrene, phenobarbital and dexamethasone. The activities of 7-ethoxyresorufin 0-dealkylase, benzphetamine, aminopyrine and erythromycin N-demethylases were measured by enzyme assays. At the same time, quantitative analysis of steroid hormones cortisol, aldosterone, testosterone and progesterone were carried out in cultural medium by radioimmunoassays. Results: The activities of benzphetamine and aminopyrine Ar-demethylase were increased in the cultural fetal adrenal cells treated with phenobarbital (0.25-1 mmol/L) for 24 h. Dexamethasone (25-100 μmol/L) also increased the activity of erythromycin W-demethylase. The activity of 7-ethoxyresorufin 0-dealkylase was undetected in the cells treated without and with 3-methylcholanthrene (0.5-2 μmol/L). Meanwhile, the contents of medium cortisol, aldosterone and progesterone were decreased after treatment with 3-methylcholanthrene. Cortisol, aldosterone and progesterone concentrations were also slightly decreased with phenobarbital. Dexamethasone enhanced the productions of cortisol and progesterone remarkably. The trend of testosterone concentration was uncertain after 3-methylcholanthrene, phenobarbital or dexamethasone treatment. Conclusion: 3-Methylcholanthrene, phenobarbital or dexamethasone could interfere with the synthesis of cortisol, aldosterone and progesterone in primary human fetal adrenal cortical cells, which likely act through xenobiotic metabolizing-related cytochrome P450 isoform activation.

  6. Consequences of 3-methylcholanthrene-type induction for the metabolism of 4-aminobiphenyl in isolated rat hepatocytes.

    Orzechowski, A; Schrenk, D; Schut, H A; Bock, K W

    1994-03-01

    Carcinogenic aromatic amines such as 4-aminobiphenyl (4-ABP) are extensively metabolized by both oxidative and conjugation reactions. Thus the burden of genotoxic metabolites of 4-ABP in a target organ is probably influenced by the balance of N-hydroxylation and alternative metabolic pathways in the hepatocyte. In freshly isolated rat hepatocytes, 4-ABP (at a substrate concentration of 10 microM) was mainly N-acetylated (54% of total metabolites), while 2% N-hydroxy-4-ABP-N-glucuronide and 21% of unconjugated N-hydroxylated metabolites were detectable. Ring-hydroxylated metabolites and the primary N-glucuronide of 4-ABP accounted for 8% and 4%, respectively. Pretreatment of rats with 3-methylcholanthrene (MC), a dioxin-type inducer of CYP1A isozymes and phenol UDP-glucuronosyltransferase (UGT1A1), led to a dramatic decrease of N-acetylated (2% of total metabolites) and an increase of N-hydroxylated (54% as free and glucuronidated compound) and ring-hydroxylated (35%) metabolites. Essentially similar effects were seen at a substrate concentration of 50 microM. Consistently, MC-type induction with beta-naphthoflavone resulted in a significant increase in the formation of DNA adducts of 4-ABP, detected by 32P-postlabeling of hepatocellular DNA. The results suggest that, similar to a previous study with 2-naphthylamine (2-NA), MC treatment leads to a marked shift from conjugation to N-oxidation. However, N-hydroxy-4-ABP (in contrast to N-hydroxy-2-NA) is mostly released from hepatocytes in the unconjugated form. PMID:8118934

  7. Transformation of SV40-immortalized human uroepithelial cells by 3-methylcholanthrene increases IFN- and Large T Antigen-induced transcripts

    Easton Marilyn J

    2010-02-01

    Full Text Available Abstract Background Simian Virus 40 (SV40 immortalization followed by treatment of cells with 3-methylcholanthrene (3-MC has been used to elicit tumors in athymic mice. 3-MC carcinogenesis has been thoroughly studied, however gene-level interactions between 3-MC and SV40 that could have produced the observed tumors have not been explored. The commercially-available human uroepithelial cell lines were either SV40-immortalized (HUC or SV40-immortalized and then 3-MC-transformed (HUC-TC. Results To characterize the SV40 - 3MC interaction, we compared human gene expression in these cell lines using a human cancer array and confirmed selected changes by RT-PCR. Many viral Large T Antigen (Tag expression-related changes occurred in HUC-TC, and it is concluded that SV40 and 3-MC may act synergistically to transform cells. Changes noted in IFP 9-27, 2'-5' OAS, IF 56, MxA and MxAB were typical of those that occur in response to viral exposure and are part of the innate immune response. Because interferon is crucial to innate immune host defenses and many gene changes were interferon-related, we explored cellular growth responses to exogenous IFN-γ and found that treatment impeded growth in tumor, but not immortalized HUC on days 4 - 7. Cellular metabolism however, was inhibited in both cell types. We conclude that IFN-γ metabolic responses were functional in both cell lines, but IFN-γ anti-proliferative responses functioned only in tumor cells. Conclusions Synergism of SV40 with 3-MC or other environmental carcinogens may be of concern as SV40 is now endemic in 2-5.9% of the U.S. population. In addition, SV40-immortalization is a generally-accepted method used in many research materials, but the possibility of off-target effects in studies carried out using these cells has not been considered. We hope that our work will stimulate further study of this important phenomenon.

  8. CD8+ T cells are crucial for the ability of congenic normal mice to reject highly immunogenic sarcomas induced in nude mice with 3-methylcholanthrene

    Boesen, M; Svane, I M; Engel, A M; Rygaard, J; Thomsen, Allan Randrup; Werdelin, O

    2000-01-01

    An attempt was made to identify the selection pressures put upon a growing tumour by CD8+ T cells. To this end tumours induced with 3-methylcholanthrene in T cell-deficient nude mice and in congenic T cell-competent nu/+ mice were transplanted to nu/+ recipients. The rejection rate of the sarcomas...... from nude mice was almost twice that of the sarcomas from nu/+ mice. Depletion of CD8+ T cells from nu/+ recipients prior to transplantation made them accept nude tumours that were consistently rejected by untreated nu/+ recipients. These findings suggest that a methylcholanthrene sarcoma during its...

  9. Expression of CYP2A3 mRNA and its regulation by 3-methylcholanthrene, pyrazole, and ß-ionone in rat tissues

    A.B. Robottom-Ferreira

    2003-07-01

    Full Text Available Cytochrome P450 (CYP 2A enzymes are involved in the metabolism of numerous drugs and hormones and activate different carcinogens. Human CYP2A6, mouse CYP2A5 and rat CYP2A3 are orthologous enzymes that present high similarity in their amino acid sequence and share substrate specificities. However, different from the human and mouse enzyme, CYP2A3 is not expressed in the rat liver. There are limited data about expression of CYP2A3 in extrahepatic tissues and its regulation by typical CYP inducers. Therefore, the objective of the present study was to analyze CYP2A3 mRNA expression in different rat tissues by RT-PCR, and to study the influence of 3-methylcholanthrene, pyrazole and ß-ionone treatment on its expression. Male Wistar rats were divided into four groups of 5 rats each, and were treated ip for 4 days with 3-methylcholanthrene (25 mg/kg body weight, pyrazole (150 mg/kg body weight, ß-ionone (1 g/kg body weight, or vehicle. Total RNA was extracted from tissues and CYP2A3 mRNA levels were analyzed by semiquantitative RT-PCR. CYP2A3 mRNA was constitutively expressed in the esophagus, lung and nasal epithelium, but not along the intestine, liver, or kidney. CYP2A3 mRNA levels were increased in the esophagus by treatment with 3-methylcholanthrene and pyrazole (17- and 7-fold, respectively, in lung by pyrazole and ß-ionone (3- and 4-fold, respectively, although not statistically significant, in the distal part of the intestine and kidney by 3-methylcholanthrene and pyrazole, and in the proximal part of the intestine by pyrazole. CYP2A3 mRNA was not induced in nasal epithelium, liver or in the middle part of the intestine. These data show that, in the rat, CYP2A3 is constitutively expressed in several extrahepatic tissues and its regulation occurs through a complex mechanism that is essentially tissue specific.

  10. Activation of liver X receptor inhibits the development of pulmonary carcinomas induced by 3-methylcholanthrene and butylated hydroxytoluene in BALB/c mice.

    Wang, Qixue; Sun, Lei; Yang, Xiaoxiao; Ma, Xingzhe; Li, Qi; Chen, Yuanli; Liu, Ying; Zhang, Di; Li, Xiaoju; Xiang, Rong; Wei, Yuquan; Han, Jihong; Duan, Yajun

    2016-01-01

    We previously reported that LXR ligand, T0901317, inhibited the growth of inoculated Lewis lung carcinoma in C57BL/6 mice by activating IFN-γ production. However, the effects of T0901317 on carcinogen-induced pulmonary carcinomas remain unknown. In this study, we initially conducted a statistical analysis on the data of human lung cancer samples extracted from the TCGA database, and determined that survival rate/time of lung cancer patients and grade of lung adenocarcinoma were positively and negatively related to lung IFN-γ levels, respectively. We then determined the inhibitory effects of T0901317 on mouse pulmonary carcinomas induced by 3-methylcholanthrene (MCA) and butylated hydroxytoluene (BHT) or urethane. We found that T0901317 reduced morbidity and mortality in MCA/BHT-injected BALB/c mice by inhibiting lung adenocarcinoma. T0901317 also protected C57BL/6 mice, but not IFN-γ deficient (IFN-γ(-/-), C57BL/6 background) mice, against MCA/BHT-induced lung hyperplasia/inflammation. In addition, we determined that T0901317 inhibited urethane-induced lung tumors in BABL/c mice. Furthermore, we determined that T0901317 prevented metastasis of 4T1 breast cancer cells in BALB/c mice. Administration of T0901317 substantially increased serum IFN-γ levels and lung IFN-γ expression in BABL/c and C57BL/6 mice. Taken together, our study demonstrates that LXR inhibits MCA/BHT-induced pulmonary carcinomas in BABL/c mice and the inhibition is associated with induction of IFN-γ production. PMID:27250582

  11. Activation of liver X receptor inhibits the development of pulmonary carcinomas induced by 3-methylcholanthrene and butylated hydroxytoluene in BALB/c mice

    Wang, Qixue; Sun, Lei; Yang, Xiaoxiao; Ma, Xingzhe; Li, Qi; Chen, Yuanli; Liu, Ying; Zhang, Di; Li, Xiaoju; Xiang, Rong; Wei, Yuquan; Han, Jihong; Duan, Yajun

    2016-01-01

    We previously reported that LXR ligand, T0901317, inhibited the growth of inoculated Lewis lung carcinoma in C57BL/6 mice by activating IFN-γ production. However, the effects of T0901317 on carcinogen-induced pulmonary carcinomas remain unknown. In this study, we initially conducted a statistical analysis on the data of human lung cancer samples extracted from the TCGA database, and determined that survival rate/time of lung cancer patients and grade of lung adenocarcinoma were positively and negatively related to lung IFN-γ levels, respectively. We then determined the inhibitory effects of T0901317 on mouse pulmonary carcinomas induced by 3-methylcholanthrene (MCA) and butylated hydroxytoluene (BHT) or urethane. We found that T0901317 reduced morbidity and mortality in MCA/BHT-injected BALB/c mice by inhibiting lung adenocarcinoma. T0901317 also protected C57BL/6 mice, but not IFN-γ deficient (IFN-γ−/−, C57BL/6 background) mice, against MCA/BHT-induced lung hyperplasia/inflammation. In addition, we determined that T0901317 inhibited urethane-induced lung tumors in BABL/c mice. Furthermore, we determined that T0901317 prevented metastasis of 4T1 breast cancer cells in BALB/c mice. Administration of T0901317 substantially increased serum IFN-γ levels and lung IFN-γ expression in BABL/c and C57BL/6 mice. Taken together, our study demonstrates that LXR inhibits MCA/BHT-induced pulmonary carcinomas in BABL/c mice and the inhibition is associated with induction of IFN-γ production. PMID:27250582

  12. Developmental regulation of the 3-methylcholanthrene- and dioxin-inducible CYP1A5 gene in chick embryo liver in vivo.

    Bentivegna, C S; Ihnat, M A; Baptiste, N S; Hamilton, J W

    1998-07-01

    The cDNA sequences for two dioxin-inducible cytochrome P450s in chicken, CYP1A4 and CYP1A5, have recently been reported which correspond to two dioxin-inducible forms of P450 previously designated as TCDDAHH and TCDDAA, respectively. The developmental expression of CYP1A4-associated aryl hydrocarbon (benzo[a]pyrene) hydroxylase (AHH) activity and its association with expression of the Ah receptor had previously been characterized in chick embryo liver. The purpose of this study was to examine the developmental regulation of the second dioxin-inducible P450 gene, CYP1A5, in chick embryo liver. A partial gene sequence for CYP1A5 indicated that the intron/exon organization of this gene was identical to that of the CYP1A1 and CYP1A2 mammalian genes and was present in a single copy in the genome. CYP1A5 mRNA was expressed basally in chick embryo liver and was highly inducible by the Ah receptor ligands, 3-methylcholanthrene, beta-naphthoflavone, and 3,4,3', 4'-tetrachlorobiphenyl (TCB), but not by the phenobarbital analog, glutethimide. CYP1A5 mRNA levels were increased 40- to 50-fold within 5 h after a single TCB treatment, corresponding to a 30- to 40-fold increase in the transcription rate of the CYP1A5 gene at this time point. In contrast to a previous report that CYP1A5 mRNA expression was inducible by estradiol, we observed no effects of estradiol or dexamethasone on CYP1A5 mRNA expression, either alone or in combination with TCB. Basal and TCB-inducible CYP1A5 mRNA expression was maximal in liver at 8 days of development and remained high throughout the remainder of embryonic development. Thus, CYP1A5 appears to be regulated in a very similar manner to CYP1A4 in chick embryo liver. PMID:9705900

  13. Aberrant methylation accounts for cell adhesion-related gene silencing during 3-methylcholanthrene and diethylnitrosamine induced multistep rat lung carcinogenesis associated with overexpression of DNA methyltransferases 1 and 3a

    To evaluate the significance of alterations in cell adhesion-related genes methylation during lung multistep carcinogenesis induced by the genotoxic carcinogens 3-methylcholanthrene (MCA) and diethylnitrosamine (DEN), tissue samples microdissected from MCA/DEN-induced rat lung carcinogenesis model were subjected to methylation-specific PCR to evaluate the DNA methylation status of CADM1, TIMP3, E-cadherin and N-cadherin. Immunohistochemistry was used to determine protein expression of CADM1, TIMP3, N-cadherin and the DNA methyltransferases (DNMTs) 1, 3a and 3b. E-cadherin hypermethylation was not detected in any tissue. CADM1, TIMP3 and N-cadherin hypermethylation was correlated with the loss of their protein expression during the progression of pathologic lesions. The prevalence of DNA methylation of at least one gene and the average number of methylated genes increased with the histological progression. DNMT1 and DNMT3a protein expression increased progressively during the stages of lung carcinogenesis, whereas DNMT3b overexpression was only found in several samples. Furthermore, DNMT1 protein expression levels were correlated with CADM1 methylation, and DNMT3a protein expression levels were correlated with CADM1, TIMP3 and N-cadherin methylation. The average number of methylated genes during carcinogenesis was significantly correlated with DNMT1 and DNMT3a protein expression levels. Moreover, mRNA expression of CADM1 significantly increased after treatment with DNMT inhibitor 5-aza-2'-deoxycytidine in CADM1-methylated primary tumor cell lines. Our findings suggest that an accumulation of hypermethylation accounts for cell adhesion-related gene silencing is associated with dynamic changes in the progression of MCA/DEN-induced rat lung carcinogenesis. We suggest that DNMT1 and DNMT3a protein overexpression may be responsible for this aberrant DNA methylation.

  14. Induction of Cyp1a1 and Cyp1b1 and formation of DNA adducts in C57BL/6, Balb/c, and F1 mice following in utero exposure to 3-methylcholanthrene

    Fetal mice are more sensitive to chemical carcinogens than are adults. Previous studies from our laboratory demonstrated differences in the mutational spectrum induced in the Ki-ras gene from lung tumors isolated from [D2 x B6D2F1]F2 mice and Balb/c mice treated in utero with 3-methylcholanthrene (MC). We thus determined if differences in metabolism, adduct formation, or adduct repair influence strain-specific responses to transplacental MC exposure in C57BL/6 (B6), Balb/c (BC), and reciprocal F1 crosses between these two strains of mice. The induction of Cyp1a1 and Cyp1b1 in fetal lung and liver tissue was determined by quantitative fluorescent real-time PCR. MC treatment caused maximal induction of Cyp1a1 and Cyp1b1 RNA 2-8 h after injection in both organs. RNA levels for both genes then declined in both fetal organs, but a small biphasic, secondary increase in Cyp1a1 was observed specifically in the fetal lung 24-48 h after MC exposure in all four strains. Cyp1a1 induction by MC at 4 h was 2-5 times greater in fetal liver (7000- to 16,000-fold) than fetal lung (2000- to 6000-fold). Cyp1b1 induction in both fetal lung and liver was similar and much lower than that observed for Cyp1a1, with induction ratios of 8- to 18-fold in fetal lung and 10- to 20-fold in fetal liver. The overall kinetics and patterns of induction were thus very similar across the four strains of mice. The only significant strain-specific effect appeared to be the relatively poor induction of Cyp1b1 in the parental strain of B6 mice, especially in fetal lung tissue. We also measured the levels of MC adducts and their disappearance from lung tissue by the P32 post-labeling assay on gestation days 18 and 19 and postnatal days 1, 4, 11, and 18. Few differences were seen between the different strains of mice; the parental strain of B6 mice had nominally higher levels of DNA adducts 2 (gestation day 19) and 4 (postnatal day 1) days after injection, although this was not statistically significant

  15. Neutrophils Are Required for 3-Methylcholanthrene-Initiated, Butylated Hydroxytoluene-Promoted Lung Carcinogenesis

    Vikis, Haris G.; Gelman, Andrew E.; Franklin, Andrew; Stein, Lauren; Rymaszewski, Amy; Zhu, Jihong; Liu, Pengyuan; Tichelaar, Jay W.; Krupnick, Alexander S.; You, Ming

    2011-01-01

    Multiple studies have shown a link between chronic inflammation and lung tumorigenesis. Inbred mouse strains vary in their susceptibility to methylcholanthrene (MCA)-initiated butylated hydroxytoluene (BHT)-promoted lung carcinogenesis. In the present study we investigated whether neutrophils play a role in strain dependent differences in susceptibility to lung tumor promotion. We observed a significant elevation in homeostatic levels of neutrophils in the lungs of tumor-susceptible BALB/cByJ...

  16. 3-methylcholanthrene induces differential recruitment of aryl hydrocarbon receptor to human promoters

    Pansoy, Andrea; Ahmed, Shaimaa; Valen, Eivind;

    2010-01-01

    responsive element. Conventional ChIP confirmed recruitment of AHR to 26 regions with target gene responses to 3MC varying from activation to inhibition to having no effect. A comparison of identified AHR-3MC bound regions with AHR-TCDD bound regions in from our previous study (Ahmed, S., Valen, E., Sandelin...... periodicity between 1.5 to 2 h. Re-treatment of cells with 3MC failed to alter the oscillatory binding profiles of AHR or ARNT. Cells became responsive to 3MC but not TCDD after 24 h of exposure to 3MC, highlighting important differences in AHR responsiveness between the two ligands. Our results reveal a...

  17. Activation of liver X receptor inhibits the development of pulmonary carcinomas induced by 3-methylcholanthrene and butylated hydroxytoluene in BALB/c mice

    Qixue Wang; Lei Sun; Xiaoxiao Yang; Xingzhe Ma; Qi Li; Yuanli Chen; Ying Liu; Di Zhang; Xiaoju Li; Rong Xiang; Yuquan Wei; Jihong Han; Yajun Duan

    2016-01-01

    We previously reported that LXR ligand, T0901317, inhibited the growth of inoculated Lewis lung carcinoma in C57BL/6 mice by activating IFN-γ production. However, the effects of T0901317 on carcinogen-induced pulmonary carcinomas remain unknown. In this study, we initially conducted a statistical analysis on the data of human lung cancer samples extracted from the TCGA database, and determined that survival rate/time of lung cancer patients and grade of lung adenocarcinoma were positively and...

  18. Effects of cigarette smoke and 3-methylcholanthrene on the disposition of phencyclidine and its N-ethylamine analogue in the isolated perfuse lung of rats

    The isolated perfused lung (IPL) of rats were used to examine the pulmonary disposition and metabolism of tritium-labeled phencyclidine (PCP) and N-ethyl-1-phenylcyclohexylamine (PCE). The IPL removed PCP and PCE from the perfusate and converted them to free and conjugated metabolities. At the conclusion of a 1-h perfusion, the lung accumulated at least 20% of the administered radioactivity and metabolized more than 30% of the added drug. Pretreatment of rats with 3-MC or cigarette smoke enhanced significantly PCP and PCE metabolism by the IPL. The concentration of conjugated PCE metabolite in the perfusate of the IPL was increased significantly by both 3-MC and cigarette smoke pretreatments whereas the concentration of conjugated PCP metabolite was not affected by cigarette smoke exposure and increased only slightly after 3-MC pretreatment. Pretreatment of rats with 3-MC or cigarette smoke also altered the amount of radioactivity accumulated by the lung tissue at the conclusion of a 1-h perfusion. Inasmuch as PCP and PCE are often abused by humans via smoke inhalation, a significant amount of these drugs may be stored or metabolized by the lung. (author)

  19. Protective effect of Ocimum sanctum on 3-methylcholanthrene, 7,12-dimethylbenz(a)anthracene and aflatoxin B1 induced skin tumorigenesis in mice

    A study on the protective effect of alcoholic extract of the leaves of Ocimum sanctum on 3-mthylcholanthrene (MCA), 7,12-dimethylbenzanthracene (DMBA) and aflatoxin B1 (AFB1) induced skin tumorigenesis in a mouse model has been investigated. The study involved pretreatment of mice with the leaf extract prior to either MCA application or tetradecanoyl phorbol acetate (TPA) treatment in a two-stage tumor protocol viz a viz, DMBA/TPA and AFB1/TPA. The results of the present study indicate that the pretreatment with alcoholic extract of the leaves of O. sanctum decreased the number of tumors in MCA, DMBA/TPA and AFB1/TPA treated mice. The skin tumor induced animals pretreated with alcoholic extract led to a decrease in the expression of cutaneous γ-glutamyl transpeptidase (GGT) and glutathione-S-transferase-P (GST-P) protein. The histopathological examination of skin tumors treated with leaf extract showed increased infiltration of polymorphonuclear, mononuclear and lymphocytic cells, decreased ornithine decarboxylase activity with concomitant enhancement of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the serum, implying the in vivo antiproliferative and immunomodulatory activity of leaf extract. The decrease in cutaneous phase I enzymes and elevation of phase II enzymes in response to topical application of leaf extract prior to MCA, AFB1, DMBA/TPA and AFB1/TPA treatment indicate the possibility of impairment in reactive metabolite(s) formation and thereby reducing skin carcinogenicity. Furthermore, pretreatment of leaf extract in the carcinogen induced animals resulted in elevation of glutathione levels and decrease in lipid peroxidation along with heat shock protein expression, indicating a scavenging or antioxidant potential of the extract during chemical carcinogenesis. Thus it can be concluded that leaf extract of O. sanctum provides protection against chemical carcinogenesis in one or more of the following mechanisms: (i) by acting as an antioxidant; (ii) by modulating phase I and II enzymes; (iii) by exhibiting antiproliferative activity

  20. Mesothelioma relative to asbestos, radiation, and methylcholanthrene

    The carcinogenicity of chrysotile asbestos fibers (Canadian and Rhodesian) for the mesothelium of pleura and peritoneum of NEDH rats was explored by injection of 2 mg of asbestos fibers suspended in saline intratracheally, intrapleurally, or intraperitoneally, with or without ancillary radiation treatment, or alternatively, by injection of asbestos plus 1 mg of 3-methylcholanthrene. A highly significant incidence of mesothelioma (3.8%) was noted in 159 rats treated with asbestos alone, as compared with 0.1% in 1417 control rats. Additional treatment with radiation or 3-methylcholanthrene increased this incidence to 11.8% and 25.5%, respectively

  1. Effects of Pristane on Cytochrome P450 Isozyme Expression in Rat Tissues

    Marvin A. Cuchens

    2005-04-01

    Full Text Available Chemical carcinogenesis studies are powerful tools to obtain information on potential mechanisms of chemical factors for malignancies. In this study Western blot analyses, using monoclonal antibodies specific for three different cytochrome P450 (CYP isozymes (CYP1A1, CYP1A2 and CYP2B, were employed to examine the effect(s of 3-methylcholanthrene and/or pristane (2,6,10,14-tetramethylpentadecane on the basal and inducible levels of expression of CYP proteins within Copenhagen rat tissues. Pristane exposure led to tissue specific differences in the CYP isozymes expressed and elicited increased CYP protein expression over 3-methylcholanthrene induced levels in microsomes isolated from liver, Peyer's Patches, and thymus. Within the context of the chemical carcinogenesis model employed in this study, these observations correlated with the induction of B-cell malignancies by low doses of 3-methylcholanthrene and of thymic lymphomas by a high 3-methylcholanthrene dose. The data suggest that pristane treatment affects CYP isozyme expression. This pristane-mediated effect clearly could be a contributing factor in the chemical carcinogenesis of the previously observed lymphoid malignancies, and a possible basis for the tumor enhancing effects of pristane.

  2. Mammary carcinogenesis in rats: basic facts and recent results in Brookhaven

    Shellabarger, C.J.; Stone, J.P.; Holtzman, s.

    1982-01-01

    Some research results from experiments investigating neutron-induced mammary carcinogenesis in rats are presented. The additive effects of neutrons and 3-methylcholanthrene on mammary adenocarcinoma were determined. Synergism between diethylstilbestrol and neutrons was likewise studied. Differences in mammary neoplastic response between strains of laboratory rats was also investigated. (ACR)

  3. Mammary carcinogenesis in rats: basic facts and recent results in Brookhaven

    Some research results from experiments investigating neutron-induced mammary carcinogenesis in rats are presented. The additive effects of neutrons and 3-methylcholanthrene on mammary adenocarcinoma were determined. Synergism between diethylstilbestrol and neutrons was likewise studied. Differences in mammary neoplastic response between strains of laboratory rats was also investigated

  4. COMPARISON OF THE LUNG ADENOMA RESPONSE IN STRAIN A/J MICE AFTER INTRAPERITONEAL AND ORAL ADMINISTRATION OF CARCINOGENS

    This study was undertaken to compare the ability of a series of compounds from different chemical classes to induce lung tumors in strain A/J mice after either ip or po administration. 3-Methylcholanthrene, benzo(a)pyrene, urethan, diethylnitrosamine, ethylnitrosourea, and dimeth...

  5. The metabolic activation of 2-naphthylamine to mutagens in the Ames test.

    Tong, S; Smith, J; Manson, D; Gorrod, J W; Ioannides, C

    1986-01-01

    The mutagenicity of 2-naphthylamine and its major metabolites in the Ames test was determined in the absence and presence of activation systems derived from rats and hamsters. In the absence of an activation system only N-hydroxy-2-naphthylamine and 2-nitrosonaphthalene were mutagenic. In the presence of activation systems derived from control and 3-methylcholanthrene-treated hamsters and Arochlor 1254-treated rats only 2-naphthylamine exhibited a mutagenic response while its hydroxy-derivatives and 2-acetamidonaphthalene were devoid of mutagenicity. Pretreatment of rats with 3-methylcholanthrene or Arochlor 1254 enhanced the mutagenicity of 2-naphthylamine while treatments with phenobarbitone, safrole and clofibrate had no significant effect. In the hamster treatment with only 3-methylcholanthrene increased the mutagenicity of 2-naphthylamine. It is concluded that the metabolic activation of 2-naphthylamine proceeds via N-hydroxylation which is preferentially catalysed by the 3-methylcholanthrene inducible forms of cytochrome P-450, whereas ring-hydroxylation appears to be a deactivation pathway. PMID:3800318

  6. Mesothelioma relative to asbestos, radiation, and methylcholanthrene

    The carcinogenicity of chrysotile asbestos fibers (Canadian and Rhodesian) for the mesothelium of pleura and peritoneum of NEDH rats was explored by injection of 2 mg of asbestos fibers suspended in saline intratracheally, intrapleurally, or intraperitoneally, with or without ancillary radiation treatment (1,000 rad to the whole body of parabiont rats or 2,000 rad to the right thorax of single rats), or alternatively, by injection of asbestos plus 1 mg of 3-methylcholanthrene. A highly significant incidence of mesothelioma (3.8%) was noted in 159 rats treated with asbestos alone, as compared with 0.1% in 1,417 control rats. Additional treatment with radiation or 3-methylcholanthrene increased this incidence to 11.8% and 25.5%, respectively, the latter increase alone being significant at the .01 level of probability

  7. Alterations of cytochrome P450-dependent monooxygenase activities in Eriocheir japonicus in response to water pollution.

    Ishizuka, M; Hoshi, H.; Minamoto, N; Masuda, M; Kazusaka, A; Fujita, S.

    1996-01-01

    Eriocheir japonicus, fresh-water crabs inhabiting rivers and estuaries in Japan, were investigated for cytochrome P450 (CYP)-dependent drug-metabolizing enzyme activities to see if these activities reflect the river pollution gradient. From the laboratory dose-response experiments, we found that the polycyclic aromatic hydrocarbon (PAH) 3-methylcholanthrene induced total CYP contents, ethoxycoumarin O-deethylase activity, and bunitrolol 4-hydroxylase activity in crab hepatopancreas. In the fi...

  8. Influence of whole body irradiation on BCG contact suppression of a rat sarcoma and tumour-specific immunity

    Experiments described here were carried out to assess the influence of host immunosuppression on Bacillus Calmette Guerin (BCG) contact suppression of a syngenetically transplanted 3-methylcholanthrene-induced rat sarcoma, Mc7, by 450 rad whole body γ radiation at 7 rad/min. The results suggest that augmented systemic responses to tumour-associated rejection antigens are not essential for BCG contact suppression but it is stated that the nature of the responses involved have yet to be elucidated. (U.K.)

  9. Liposome-encapsulated superoxide dismutase prevents liver necrosis induced by acetaminophen.

    Nakae, D.; Yamamoto, K; Yoshiji, H; Kinugasa, T.; Maruyama, H; Farber, J. L.; Konishi, Y

    1990-01-01

    Liposome-encapsulated human recombinant superoxide dismutase (LSOD) protected male rats that were pretreated with 3-methylcholanthrene from the liver necrosis produced by acetaminophen. By contrast, SOD-free liposomes, free SOD, or heat-denatured LSOD had no protective effect. Liposome-encapsulated SOD did not simply delay the onset of liver necrosis. A second dose of LSOD at 12 hours prevented the necrosis of the liver as assessed 24 hours after treatment with 500 mg/kg body weight of acetam...

  10. Acetaminophen structure-toxicity studies: In vivo covalent binding of a nonhepatotoxic analog, 3-hydroxyacetanilide

    High doses of 3-hydroxyacetanilide (3HAA), a structural isomer of acetaminophen, do not produce hepatocellular necrosis in normal male hamsters or in those sensitized to acetaminophen-induced liver damage by pretreatment with a combination of 3-methylcholanthrene, borneol, and diethyl maleate. Although 3HAA was not hepatotoxic, the administration of acetyl-labeled [3H or 14C]3HAA (400 mg/kg, ip) produced levels of covalently bound radiolabel that were similar to those observed after an equimolar, hepatotoxic dose of [G-3H]acetaminophen. The covalent nature of 3HAA binding was demonstrated by retention of the binding after repetitive organic solvent extraction following protease digestion. Hepatic and renal covalent binding after 3HAA was approximately linear with both dose and time. In addition, 3HAA produced only a modest depletion of hepatic glutathione, suggesting the lack of a glutathione threshold. 3-Methylcholanthrene pretreatment increased and pretreatment with cobalt chloride and piperonyl butoxide decreased the hepatic covalent binding of 3HAA, indicating the involvement of cytochrome P450 in the formation of the 3HAA reactive metabolite. The administration of multiple doses or a single dose of [ring-3H]3HAA to hamsters pretreated with a combination of 3-methylcholanthrene, borneol, and diethyl maleate produced hepatic levels of 3HAA covalent binding that were in excess of those observed after a single, hepatotoxic acetaminophen dose. These data suggest that the nature and/or the intracellular processing of the reactive metabolites of acetaminophen and 3HAA are different. These data also demonstrate that absolute levels of covalently bound xenobiotic metabolites cannot be utilized as absolute predictors of cytotoxic potential

  11. Venom of Indian monocellate cobra and Russell's viper show anticancer activity in experimental models.

    Debnath, Anindita; Chatterjee, Uttora; Das, Minati; Vedasiromoni, Joseph R; Gomes, Aparna

    2007-05-22

    Indian monocellate cobra (Naja kaouthia) and Russell's viper (Vipera russelli) are common snakes of the East Indian sub-peninsula. The anticarcinogenic activities of their crude venoms were studied on carcinoma, sarcoma and leukemia models. Sub-lethal doses of venoms showed cytotoxicity on Ehrlich ascites carcinoma (EAC) cells in vivo. The venoms increased lifespan of EAC mice and strengthened the impaired host antioxidant system. Sarcoma formation in mice (3-methylcholanthrene induced) after venom treatment was significantly less (p venoms displayed potent cytotoxic and apoptogenic effect on human leukemic cells (U937/K562). The venoms reduced cell proliferation rate (p venoms may be attributed to the difference in their constituents. PMID:17258413

  12. Potentiation in the intact rat of the hepatotoxicity of acetaminophen by 1,3-bis(2-chloroethyl)-1-nitrosourea.

    Nakae, D; Oakes, J W; Farber, J L

    1988-12-01

    Studies of the killing of cultured hepatocytes by acetaminophen indicate that the cells are injured by an oxidative stress that accompanies the metabolism of the toxin (J. L. Farber et al. (1988) Arch. Biochem. Biophys. 267, 640-650). The present report documents that the essential features of the killing of cultured hepatocytes by acetaminophen are reproduced in the intact animal. Male rats had no evidence of liver necrosis 24 h after administration of up to 1000 mg/kg of acetaminophen. Induction of mixed function oxidase activity by 3-methylcholanthrene increased the hepatotoxicity of acetaminophen. Inhibition of glutathione reductase by 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) potentiated the hepatotoxicity of acetaminophen in male rats induced with 3-methylcholanthrene. Whereas the pretreatment with BCNU reduced the GSH content by 40%, a comparable depletion of GSH by diethylmaleate did not potentiate the toxicity of acetaminophen. The antioxidant diphenylphenylenediamine (25 mg/kg) and the ferric iron chelator deferoxamine (1000 mg/kg) prevented the liver necrosis produced by 500 mg/kg acetaminophen in rats pretreated with BCNU. Neither protective agent prevented the fall in GSH produced by acetaminophen. It is concluded the conditions of the irreversible injury of cultured hepatocytes by acetaminophen previously reported are not necessarily different from those that obtain in the intact rat with this toxin. PMID:3214175

  13. Induction of active melanocytes in mouse skin by carcinogens: a new method for detection of skin carcinogens.

    Iwata, K; Inui, N; Takeuchi, T

    1981-01-01

    Application of potent skin carcinogens, such as 7,12-dimethylbenz[a]anthracene, 3-methylcholanthrene, benzo[a]pyrene and 4-nitroquinoline-1-oxide, induced numerous dihydroxyphenylalanine (dopa)-positive cells in the interfollicular epidermis of C57BL/6 mice in a dose- and time-dependent fashion. Chrysene, a weak skin carcinogen, and croton oil, a tumor promoter, also induced 3--4 times more dopa-positive cells than acetone. Liver carcinogens, such as 3'-methyl-4-dimethylaminoazobenzene and N-2-acetylaminofluorene, and non-carcinogenic aromatic hydrocarbons, such as anthracene, fluoranthene, fluorene and pyrene, did not induce increase in these cells. These results indicate that increase in the number of dopa-positive cells after application of chemicals is well correlated with the abilities of these compounds to induce skin carcinogenesis and suppress sebaceous glands. PMID:7273337

  14. Influence of whole body irradiation on BCG contact suppression of a rat sarcoma and tumour-specific immunity

    An assessment has been made of the influence of host immunosuppression on Bacillus Calmette Guerin (BCG) contact suppression of a syngenetically transplanted, highly immunogenic, 3-methylcholanthrene-induced rat sarcoma. Experiments have been carried out with transplanted cells derived from solid tissue and from an in vitro culture line, the latter excluding the possibility of transfer to immunosuppressed rats of lymphoid cells present in preparations from solid tissue. Normal or whole-body γ-irradiated (450 rad 24 hours before injection) rats were injected s.c. with mixtures of tumour cells and BCG organisms, and some of the animals received a simultaneous challenge of tumour cells alone at a contralateral subcutaneous site. Whole-body irradiation did not abrogate the local suppressive effect of BCG injected in admixture with sarcoma cells, whereas in contrast the development of tumour-specific host immunity, normally occurring concomitantly with rejection of mixed inocula, was totally abrogated by whole-body irradiation. (U.K.)

  15. Pristane-induced effects on cytochrome P-4501A, ornithine decarboxylase and putrescine in rats.

    Harper, C M; Soni, M G; Mehendale, H M; Cuchens, M A

    1995-08-16

    The effects of pristane (2,6,10,14-tetramethylpentadecane) on cytochrome P-4501A (cP4501A) activity in microsomes, as well as on ornithine decarboxylase (ODC) activity and concomitant putrescine levels were examined in Copenhagen rats. In general, pristane treatment led to increased cP4501A levels when compared to basal levels, while co-treatment with 3-methylcholanthrene (3-MC) and pristane elicited augmented cP4501A responses when compared to responses induced by 3-MC alone. Increases in both ODC activity and putrescine levels were also observed in pristane treated rats. Collectively, these results indicate that pristane influences cP4501A activity and elicits promoter-like responses as reflected in elevated ODC activity and increased amount of putrescine. PMID:7656217

  16. Differential effects of chronic alcohol administration to rats on the activation of aromatic amines to mutagens in the Ames test.

    Steele, C M; Ioannides, C

    1986-05-01

    Male Wistar albino rats were maintained on alcohol-containing liquid diets for 4 weeks. Hepatic post-mitochondrial preparations derived from these animals were more efficient than control in activating 4-aminobiphenyl and 2-aminofluorene to mutagens in the Ames test. The alcohol-induced enhancement in mutagenicity was not inhibited by dimethylsulphoxide indicating that the generation of hydroxyl radicals is not involved. The activation of 2-naphthylamine was not affected by the treatment with alcohol but the mutagenicities of 2-aminoanthracene, benzo[a]pyrene and 3-methylcholanthrene were inhibited. The same treatment markedly increased hepatic microsomal aniline p-hydroxylase and ethoxyresorufin O-de-ethylase activities and to a lesser extent benzphetamine N-demethylase and microsomal levels of total cytochromes P-450. It is concluded that chronic alcohol administration to rats modulates the metabolic activation of pre-carcinogens to their reactive intermediates presumably by causing the redistribution of cytochrome P-450 isozymes. PMID:3009048

  17. Induction of hepatic cytochrome P450 isozymes, benzo(a)pyrene metabolism and DNA binding following exposure to polycyclic aromatic hydrocarbon residues generated during repeated fish fried oil in rats

    In the present study the effect of repeated fish fried oil (RFFO) and its extract (RFFE) on hepatic cytochrome P450 (CYP) isozymes, benzo(a)pyrene (BP) metabolism and DNA adduct formation was undertaken. HPLC analysis of RFFO showed the presence of several polycyclic aromatic hydrocarbons. CYP in microsomes from control and RFFO-treated animals showed a peak at 450 nm; however, a shift of 2 nm in the SORET region along with significant induction was observed in microsomes prepared from 3-methylcholanthrene (MC)- and RFFE-treated animals. Activities of hepatic ethoxyresorufin-O-deethylase, methoxyresorufin-O-deethylase, aryl hydrocarbon hydroxylase and erythromycin-N-demethylase were found to be significantly (P 3H]-BP to calf thymus DNA. The overall results suggest that exposure to RFFE may induce hepatic CYP isozymes thereby producing enhanced reactive metabolites with a potential to bind with DNA that may result in cancer

  18. Comparative study on glutathione transferases of rat brain and testis under the stress of phenobarbitol and β-methylcholanthrene

    THYAGARAJU K.; HEMAVATHI B.; VASUNDHARA K.; RAO A.D.; DEVI K.N.

    2005-01-01

    A comparative study was made on the tissue specific expression of glutathione transferases (GST) in brain and testis after exposure of rat to phenobarbitol (PB) and 3-methylcholanthrene (MC). Glutathione transferases, a family of multifunctional proteins are involved in intracellular transport processes and in detoxication of electrophilic xenobiotics by catalyzing reactions such as conjugation, isomerization, reduction and thiolysis. On purification, the yield of GST proteins by affinity chromatography was 39% in testis and 32% in brain. The affinity purified testis GSTs were resolved by chromatofocusing into six anionic and four cationic isozymes, and in brain glutathione transferases were resolved into four anionic and three cationic isozymes, suggesting the presence of multiple isozymes with Yc, Yb, Y3 and Yδ in both of them. In testis and brain, these isozymes at identical pI values showed variable functions with a battery of substrates and the cationic isozymes of brain and testis showed identical properties in CHP (cumene hydroperoxide) at pH values of above 7.0. Substrate specificity studies and immunoblot analysis of testis and brain proteins revealed that they play a predominant role in the detoxication of phenobarbitol or 3-methylcholanthrene. Expression of the isozymes in testis and brain on exposure to PB and MC indicated elevated subunit variation. In both testis and brain, Yδ ofπclass was expressed on PB treatment and Yc of α class and Y3 of μ class was expressed in MC treated testis and only Yc was predominantly expressed in MC treated brain. Thus these subunits expression is considered as markers for carcinogenesis and specific to chemical toxicity under phenobarbitol and 13-methylcholanthrene stress.

  19. Involvement of hepatocyte nuclear factor 1 in the regulation of the UDP-glucuronosyltransferase 1A7 (UGT1A7) gene in rat hepatocytes.

    Metz, R P; Auyeung, D J; Kessler, F K; Ritter, J K

    2000-08-01

    UDP-glucuronosyltransferase 1A7 (UGT1A7) is a major UGT contributing to the glucuronidation of xenobiotic phenols in rats. Its expression in rat liver is tightly regulated, with low constitutive and high inducible expression in response to aryl hydrocarbon receptor ligands and oltipraz. Previously, we reported the absence of 3-methylcholanthrene- or oltipraz-responsive elements in the 1.6-kbp region flanking the UGT1A7 promoter. However, potential binding sites were noted for several liver-enriched transcription factors. Here we show that deletion of the hepatic nuclear factor (HNF)3, HNF4, and CCAAT-enhancer binding protein-like binding sites had no effect on the expression of a UGT1A7 reporter plasmid, p(-965/+56)1A7-Luc, in primary rat hepatocytes. The full activity of the promoter was contained in the region between bases -157 and +76. Two sites of binding by rat liver nuclear proteins were detected in this region by DNase footprinting. PR-1 corresponded to the HNF1-like binding site between bases -52 and -38, whereas PR-2 was located between -30 to -6. Gel retardation studies supported the presence of HNF1alpha in the PR-1 DNA-liver nuclear protein complex. Mutation of PR-1 inhibited binding in the gel shift assay, prevented activation by overexpressed HNF1 in human embryonic kidney cells, and reduced by >80% the maximal luciferase activities expressed from basal and 3-methylcholanthrene-responsive UGT1A7 gene reporter constructs in primary rat hepatocytes. These data provide evidence for an important stimulatory role of HNF1 in promoting UGT1A7 gene expression in rat liver. PMID:10908299

  20. Caffeic acid phenethyl ester inhibits 3-MC-induced CYP1A1 expression through induction of hypoxia-inducible factor-1α

    Kim, Hyung Gyun [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of); Han, Eun Hee [Division of Life Science, Korea Basic Science Institute, Daejeon (Korea, Republic of); Im, Ji Hye; Lee, Eun Ji; Jin, Sun Woo [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of); Jeong, Hye Gwang, E-mail: hgjeong@cnu.ac.kr [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of)

    2015-09-25

    Caffeic acid phenethyl ester (CAPE), a natural component of propolis, is reported to have anticarcinogenic properties, although its precise chemopreventive mechanism remains unclear. In this study, we examined the effects of CAPE on 3-methylcholanthrene (3-MC)-induced CYP1A1 expression and activities. CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. Moreover, CAPE inhibited 3-MC-induced CYP1A1 activity, mRNA expression, protein level, and promoter activity. CAPE treatment also decreased 3-MC-inducible xenobiotic-response element (XRE)-linked luciferase, aryl hydrocarbons receptor (AhR) transactivation and nuclear localization. CAPE induced hypoxia inducible factor-1α (HIF-1α) protein level and HIF-1α responsible element (HRE) transcriptional activity. CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 protein expression. Taken together, CAPE decreases 3-MC-mediated CYP1A1 expression, and this inhibitory response is associated with inhibition of AhR and HIF-1α induction. - Highlights: • CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. • CAPE inhibited 3-MC-induced CYP1A1 expression. • CAPE induced HIF-1α induction. • CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 expression.

  1. Cell kinetics in mouse lung following administration of carcinogens and butylated hydroxytoluene

    A series of experiments is described which was designed to test the hypothesis that, in mouse lung, enhancement of tumor development could occur independently of overall alveolar cell hyperplasia. Male A/J mice were given 1000 mg/kg of urethane or 10 mg/kg of 3-methylcholanthrene (MCA). Alveolar cells were labeled through continuous infusion of [3H]thymidine for 6 weeks after administration of the carcinogen. Urethane produced a significant hyperplasia of the type II alveolar cell population, whereas MCA had no such effect. Five repeated injections of 300 mg/kg of butylated hydroxytoluene (BHT), a procedure known to enhance lung tumor development, produced cell hyperplasia only during the first 2 weeks; later the mice became resistant to the action of BHT. In animals treated with piperonyl butoxide prior to BHT, cell proliferation was abolished. BHT still had a small but significant enhancing effect on tumor development. However, this effect was dwarfed by the observation that piperonyl butoxide alone greatly inhibited tumor development. The data do not allow exclusion of alveolar cell hyperplasia as a mechanism in BHT-mediated enhancement of mouse lung tumor development. 19 references, 4 figures, 3 tables

  2. Caffeic acid phenethyl ester inhibits 3-MC-induced CYP1A1 expression through induction of hypoxia-inducible factor-1α

    Caffeic acid phenethyl ester (CAPE), a natural component of propolis, is reported to have anticarcinogenic properties, although its precise chemopreventive mechanism remains unclear. In this study, we examined the effects of CAPE on 3-methylcholanthrene (3-MC)-induced CYP1A1 expression and activities. CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. Moreover, CAPE inhibited 3-MC-induced CYP1A1 activity, mRNA expression, protein level, and promoter activity. CAPE treatment also decreased 3-MC-inducible xenobiotic-response element (XRE)-linked luciferase, aryl hydrocarbons receptor (AhR) transactivation and nuclear localization. CAPE induced hypoxia inducible factor-1α (HIF-1α) protein level and HIF-1α responsible element (HRE) transcriptional activity. CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 protein expression. Taken together, CAPE decreases 3-MC-mediated CYP1A1 expression, and this inhibitory response is associated with inhibition of AhR and HIF-1α induction. - Highlights: • CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. • CAPE inhibited 3-MC-induced CYP1A1 expression. • CAPE induced HIF-1α induction. • CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 expression

  3. Effect of heavy metals on the metabolism of benzo(a)pyrene in rats

    Honey, S.A.; Yuan, Zhi-Xin; Kumar, S.; Sikka, H.C. [State Univ. of New York College, Buffalo, NY (United States)

    1996-12-31

    In order to investigate the interaction of heavy metals and PAHs, we have examined the effect of methylmercuric chloride and cadmium chloride on the oxidative metabolism by rats of benzo(a)pyrene [BaP], a model carcinogenic PAR Treatment of male rats with 2.5 or 5.0 mg/kg methylmercury (ip) reduced the rate of metabolism of BaP by liver microsomes by 38.7 and 62.2%, respectively. Cadmium was more potent than methylmercury, decreasing the rate of metabolism of BaP by 28.4, 52.2, and 69.7% by liver microsomes of rats treated with 0.5, 1.0, and 1.5 mg/kg of cadmium, respectively. The liver microsomes from animals treated with methylmercury or cadmium produced a greater proportion of BP-phenols and a lower portion of BP-diols than did the microsomes from untreated animals, suggesting that both metals also inhibit the activity of epoxide hydrase. Neither methylmercury nor cadmium had an effect on the proportion of BP-quinones formed by liver microsomes. Treatment of rats with methylmercury or cadmium did not inhibit the metabolism of BaP by liver microsomes from animals treated with 3-methylcholanthrene (3-MC) prior to metal administration, suggesting that 3-MC treatment protects against the effect of methylmercury or cadmium on the oxidative metabolism of BaP.

  4. Role of lipid peroxidation in cytochrome P-450 degradation in hepatocytes and lymphocytes and stabilizing effects of antioxidants

    Kagan, V.; Novikov, K.; Bogdanova, E.; Prilipko, L.

    1986-01-01

    Incubation of primary culture of hepatocytes was accompanied by spontaneous degradation of cytochrome P-450 (P-450) and by a decrease of its monooxygenase activities. Accumulation of lipid peroxidation (LPO) products also occurred. Addition of LPO inducers (Fe/sup 2 +/-ADP, NADPH) to the medium led to a drastic acceleration of both processes. Synthetic free radical scavengers (butylated hydroxytoluene, 3-hydroxybenzene, alpha-naphthol) prevented LPO activation and protected P-450 against degradation. Phenolic derivatives of 3,4-benzpyrene, formed as a result of its hydroxylation, also had an antioxidant and a protective effect on P-450. Similarly, incubation of human peripheral blood lymphocytes stimulated by PHA resulted in a rapid inhibition of arylhydrocarbon hydroxylase (AHH). In lymphocytes stimulated by PHA and then induced by 3-methylcholanthrene, the sharply increased AHH activity remained unchanged for a long period and no LPO products were accumulated. Exogenous LPO inducers did not either stimulate LPO and were ineffective on the AHH activity. This was due to the presence of 3-methyl cholanthrene phenolic derivatives formed during lymphocytes induction. It is concluded that free radical scavengers could be used as P-450 stabilizers in cell cultures.

  5. Qualitative study of three cell culture methods.

    Wang, Aiguo; Xia, Tao; Ran, Peng; Chen, Xuemin; Nuessler, Andreas K

    2002-01-01

    Primary rat hepatocytes were cultured using different in vitro models and the enzyme leakage, albumin secretion, and cytochrome P450 1A (CYP 1A) activity were observed. The results showed that the level of LDH was decreased over time in culture. However, on day 5, LDH showed a significant increase in monolayer culture (MC) while after day 8 no LDH was detectable in sandwich culture (SC). The levels of AST and ALT did not change significantly over the investigated time. The CYP 1A activity was gradually decreased in a time-dependent manner in MC and SC. The decline of CYP 1A was faster in MC than in SC. This effect was partially reversed by using cytochrome P450 (CYP450) inducer such as Omeprazol and 3-methylcholanthrene (3-MC) and the CYP 1A induction was always higher in MC than in SC. In bioreactor basic CYP 1A activity was preserved over 2 weeks and the highest albumin production was observed in bioreactor followed by SC and MC. Taken together, it was indicated each investigated model had its advantages and disadvantages. It was also underlined that various in vitro models may address different questions. PMID:12674760

  6. [Effect evaluation of three cell culture models].

    Wang, Aiguo; Xia, Tao; Yuan, Jing; Chen, Xuemin

    2003-11-01

    Primary rat hepatocytes were cultured using three kinds of models in vitro and the enzyme leakage, albumin secretion, and cytochrome P450 1A (CYP 1A) activity were observed. The results showed that the level of LDH in the medium decreased over time in the period of culture. However, on 5 days, LDH showed a significant increase in monolayer culture (MC) while after 8 days LDH was not detected in sandwich culture (SC). The levels of AST and ALT in the medium did not change significantly over the investigated time. The basic CYP 1A activity gradually decreased with time in MC and SC. The decline of CYP 1A in rat hepatocytes was faster in MC than that in SC. This effect was partially reversed by using cytochrome P450 (CYP450) inducers such as omeprazol and 3-methylcholanthrene (3-MC) and the CYP 1A induction was always higher in MC than that in SC. Basic CYP 1A activity in bioreactor was keeped over 2 weeks and the highest albumin production was observed in bioreactor, and next were SC and MC. In conclusion, our results clearly indicated that there have some advantages and disadvantages in each of models in which can address different questions in metabolism of toxicants and drugs. PMID:14963896

  7. Relationship between the radioisotopic footpad assay and other immunological assays in tumor bearing rats

    KMT-17, a fibrosarcoma induced by 3-methylcholanthrene in a WKA rat, is a sensitive tumor to various kinds of immunological assays and is a suitable model tumor for the study of the immune status in tumor bearing hosts. The antitumor immune response of KMT-17 bearing rats was studied by a radioisotopic footpad assay (FPA) in comparison with other in vivo and in vitro assays. Delayed hypersensitivity to tumor antigens measured by the FPA was observed from the 8th day after transplantation of KMT-17 cells, reached a peak on the 12 - 15th day, and then declined in the late stage on the 17th day. The kinetics of the FPA correlated well with those of an in vivo Winn assay and of an in vitro lymphocyte cytotoxicity assay (51Cr-release assay). The appearance of an antitumor antibody detected by a complement dependent cytotoxicity test also correlated well with the kinetics of the FPA. A growth inhibition assay (GIA) for non-specific cell-mediated immunity also showed similar kinetics to that of the FPA. The delayed hypersensitivity footpad reaction to tumor cell extracts measured by this FPA was tumor-specific. These results suggest that the FPA is a simple and reliable in vivo assay for evaluating antitumor immunity in tumor bearing hosts. (author)

  8. Transcriptomic responses of European flounder (Platichthys flesus) to model toxicants

    The temporal transcriptomic responses in liver of Platichthys flesus to model environmental pollutants were studied over a 16-day time span after intraperitoneal injection with cadmium chloride (50 μg/kg in saline), 3-methylcholanthrene (25 mg/kg in olive oil), Aroclor 1254 (50 mg/kg in olive oil), tert-butyl-hydroperoxide (5 mg/kg in saline), Lindane (25 mg/kg in olive oil), perfluoro-octanoic acid (100 mg/kg in olive oil) and their vehicles, olive oil (1 ml/kg) or saline (0.9%). Statistical, gene ontology and supervised analysis clearly demonstrated the progression from acute effects, biological responses to and recovery from the treatments. Key biological processes disturbed by the individual treatments were characterised by gene ontology analyses and individual toxicant-responsive genes and pathways were identified by supervised analyses. Responses to the polyaromatic and chlorinated aromatic compounds showed a degree of commonality but were distinguishable and they were clearly segregated from the responses to the pro-oxidants cadmium and the organic hydroperoxide, as well as from the peroxisomal proliferator, perfluoro-octanoic acid. This study demonstrated the utility of the microarray technique in the identification of toxicant-responsive genes and in discrimination between modes of toxicant action

  9. Induction and inhibition of benzo(a)pyrene metabolism in human epidermal keratinocytes and dermal fibroblasts

    The effects of different growth conditions and various cytochrome P-450 inducers and inhibitors were examined on the benzo(a)pyrene (BP) metabolism of human skin cells in vitro. First, three different populations of neonatal foreskin fibroblasts were treated with 0.98 μM [G-3H]-BP at 9.6 Ci/mmole for 24 hours and the organic-extractable metabolites in the extracellular, the cytoplasmic, and the nuclear fractions were analyzed by high-pressure liquid chromatography (HPLC). Confluent cultures (contact-inhibited cells), which were nontransformable, metabolized BP to a much greater extent than the transformable populations, randomly-proliferating cultures (cells in logarithmic growth) and synchronized cultures (cells treated in S phase). The major extracellular BP metabolites detected were the 9,10-diol, the 7,8-diol, and the phenols, including all four tetrols observed only in the confluent cells. From this data, the state of confluency (i.e. the model for the in vivo state of skin cells) induced enzymes which catalyze primarily the detoxification pathways leading to the formation of metabolites which are readily excreted whereas cells which are actively dividing or synchronized induced the formation of metabolites from activation pathways that led to transformation. Next, the effects of four inducers (3-methylcholanthrene (3-MCA), phenobarbital (PB), isosafrole, and Arochlor 1254) and an inhibitor (butylated hydroxyanisole (BHA)) on the BP metabolism of human epidermal keratinocytes were evaluated

  10. Effects of Intermediate Metabolites of 37 Xenobiotics on the Catalytic Activities of Reconstituted Cytochrome P—450IIB1 and P—4501A1 Enzyme Systems

    YANGMINGXUE; VANGLIE; 等

    1993-01-01

    Direct effects of intermediate metabolites of 37 different xenobiotics on the catalytic activities of bothn reconstitute cytochrome P-450ⅡP-45PIA1 enzyme systems were studied by determination of NADPH oxidation at various intervals after initiation of the reaction.The results showed that cytochrome P-4500ⅡB isozyme was much more likely than cytochrome P-450IA1 isozyme to be attacked by the reactive intermediates formed by some xenobiotics with smaller molecular weight and lose its catalytics activities.These xenobiotics were carbon tetrachloride,chloroform,carbon disulfide,benzene,parathion, methylparathion,methyldurshan and dimethylnitrosamine.In contrast,however,steadily increasing metabolic activities were observed toards benzo(a)pyrene,3-methylcholanthrene and polychlorinated biphenyls in reconstituted cytochrome P-450IA1 enzyme system as the reaction time prolonged within 4min.The method discussed in this paper could e be used as a simple and convenient way to observe directly the autocatalytic destruction of P-450 enzymes by soe chemical agents.

  11. The effect of plant phenolics on the formation of 7,12-dimethylbenz[a]anthracene-DNA adducts and TPA-stimulated polymorphonuclear neutrophils chemiluminescence in vitro

    Phenolics, common plant constituents, form up an important part of human diet and are considered potential chemopreventive agents. In the present study, structurally diverse phenolics, such as tannic acid, protocatechuic acid, chlorogenic acid and resveratrol, were investigated for their inhibitory effects on covalent binding of 7,12-dimethylbenz[a]anthracene (DMBA) to DNA in vitro and the suppression of oxidative burst in 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated human polymorphonuclear neutrophils (PMNs). 32P-postlabeling analysis of DNA incubated with DMBA in the presence of 3-methylcholanthrene (3-MC)-induced microsomes produced three major adducts derived from anti-, syn- and anti-dihydrodiol epoxides through reactions with dGuo and dAdo, respectively. Phenolic compounds at the concentration of 150 μM reduced the levels of all DMBA-DNA adducts by 55-98%. The most dramatic effect was observed in case of tannic acid, which completely inhibited the formation of DMBA-dAdo adducts. Chlorogenic acid was the least effective inhibitor of DMBA-DNA adducts formation particularly syn-DMBADE-dAdo (20%). Human neutrophils showed a significant dose-related decrease of TPA-induced chemiluminescence after pretreatment with phenolic compounds. The most effective inhibitors were tannic acid and resveratrol with IC50=5.19 and 5.76 μM, respectively. These results suggest that the suppression of reactive oxygen species (ROS) and carcinogen-DNA adducts formation may be important for anticarcinogenic activity of the examined phenolics

  12. Radiation carcinogenesis. Comprehensive final report, 16 May 1979-31 December 1980

    Warren, S; Brown, C E; Gates, O

    1981-03-01

    This abstract covers three main areas of investigation: mesothelioma induction by asbestos, radiation tumorigenesis and transplantable tumors. Canadian and Rhodesian asbestos fibers have been administered under anesthesia to rats by intratracheal, intrapleural and intraperitoneal injection. Additional groups were given 3-methylcholanthrene or x-radiation along with asbestos. A large series of mice also treated as above have displayed mesotheliomas. In addition, glass fiber injections and feeding of asbestos were done and have produced negative results to date. The carcinogenic effect of whole-body radiation on hemi-irradiated parabiont partners exposed to a single 1000 R dose of x-ray was evidenced by a significant increase in the incidence of malignant tumors in only six tissues: skin, supporting soft tissue, kidney, bone, pancreatic islets and ovary. In the male adrenal medulla and in the female breast genetic and parabiotic hormonal factors were judged to exert a significant effect. The occurrence of incisional (anastomotic) sarcomas in significant numbers in hemi-irradiated and parabiont control pairs suggests the operation of mechanical factors complicating the healing process, only slightly enhanced by radiation. One of the very valuable but unanticipated developments of the rat radiation program was the isolation of two transplantable endocrine tumors with strong hormonal potentials: an insulinoma of the pancreas and a pheochromocytoma of the adrenal medulla.

  13. Noble metal nanoparticle-induced oxidative stress modulates tumor associated macrophages (TAMs) from an M2 to M1 phenotype: An in vitro approach.

    Pal, Ramkrishna; Chakraborty, Biswajit; Nath, Anupam; Singh, Leichombam Mohindro; Ali, Mohammed; Rahman, Dewan Shahidur; Ghosh, Sujit Kumar; Basu, Abhishek; Bhattacharya, Sudin; Baral, Rathindranath; Sengupta, Mahuya

    2016-09-01

    Diagnosis of cancer and photothermal therapy using optoelectronic properties of noble metal nanoparticles (NPs) has established a new therapeutic approach for treating cancer. Here we address the intrinsic properties of noble metal NPs (gold and silver) as well as the mechanism of their potential antitumor activity. For this, the study addresses the functional characterization of tumor associated macrophages (TAMs) isolated from murine fibrosarcoma induced by a chemical carcinogen, 3-methylcholanthrene (MCA). We have previously shown antitumor activity of both gold nanoparticles (AuNPs) and silver nanoparticle (AgNPs) in vivo in a murine fibrosarcoma model. In the present study, it has been seen that AuNPs and AgNPs modulate the reactive oxygen species (ROS) and reactive nitrogen species (RNS) production, suppressing the antioxidant system of cells (TAMs). Moreover, the antioxidant-mimetic action of these NPs maintain the ROS and RNS levels in TAMs which act as second messengers to activate the proinflammatory signaling cascades. Thus, while there is a downregulation of tumor necrosis factor-α (TNF-α) and Interleukin-10 (IL-10) in the TAMs, the proinflammatory cytokine Interleukin-12 (IL-12) is upregulated resulting in a polarization of TAMs from M2 (anti-inflammatory) to M1 (pro-inflammatory) nature. PMID:27344639

  14. Radiation carcinogenesis. Comprehensive final report, 16 May 1979-31 December 1980

    This abstract covers three main areas of investigation: mesothelioma induction by asbestos, radiation tumorigenesis and transplantable tumors. Canadian and Rhodesian asbestos fibers have been administered under anesthesia to rats by intratracheal, intrapleural and intraperitoneal injection. Additional groups were given 3-methylcholanthrene or x-radiation along with asbestos. A large series of mice also treated as above have displayed mesotheliomas. In addition, glass fiber injections and feeding of asbestos were done and have produced negative results to date. The carcinogenic effect of whole-body radiation on hemi-irradiated parabiont partners exposed to a single 1000 R dose of x-ray was evidenced by a significant increase in the incidence of malignant tumors in only six tissues: skin, supporting soft tissue, kidney, bone, pancreatic islets and ovary. In the male adrenal medulla and in the female breast genetic and parabiotic hormonal factors were judged to exert a significant effect. The occurrence of incisional (anastomotic) sarcomas in significant numbers in hemi-irradiated and parabiont control pairs suggests the operation of mechanical factors complicating the healing process, only slightly enhanced by radiation. One of the very valuable but unanticipated developments of the rat radiation program was the isolation of two transplantable endocrine tumors with strong hormonal potentials: an insulinoma of the pancreas and a pheochromocytoma of the adrenal medulla

  15. The aryl hydrocarbon receptor and glucocorticoid receptor interact to activate human metallothionein 2A

    Although the aryl hydrocarbon receptor (AHR) and glucocorticoid receptor (GR) play essential roles in mammalian development, stress responses, and other physiological events, crosstalk between these receptors has been the subject of much debate. Metallothioneins are classic glucocorticoid-inducible genes that were reported to increase upon treatment with AHR agonists in rodent tissues and cultured human cells. In this study, the mechanism of human metallothionein 2A (MT2A) gene transcription activation by AHR was investigated. Cotreatment with 3-methylcholanthrene and dexamethasone, agonists of AHR and GR respectively, synergistically increased MT2A mRNA levels in HepG2 cells. MT2A induction was suppressed by RNA interference against AHR or GR. Coimmunoprecipitation experiments revealed a physical interaction between AHR and GR proteins. Moreover, chromatin immunoprecipitation assays indicated that AHR was recruited to the glucocorticoid response element in the MT2A promoter. Thus, we provide a novel mechanism whereby AHR modulates expression of human MT2A via the glucocorticoid response element and protein–protein interactions with GR. - Highlights: • Aryl hydrocarbon receptor forms a complex with glucocorticoid receptor in cells. • Human metallothionein gene is regulated by the AHR and GR interaction. • AHR–GR complex binds to glucocorticoid response element in metallothionein gene. • We demonstrated a novel transcriptional mechanism via AHR and GR interaction

  16. The aryl hydrocarbon receptor and glucocorticoid receptor interact to activate human metallothionein 2A

    Sato, Shoko, E-mail: satosho@rs.tus.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan); Shirakawa, Hitoshi, E-mail: shirakah@m.tohoku.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan); Tomita, Shuhei, E-mail: tomita@med.tottori-u.ac.jp [Division of Molecular Pharmacology, Department of Pathophysiological and Therapeutic Science, Yonago 683-8503 (Japan); Tohkin, Masahiro, E-mail: tohkin@phar.nagoya-cu.ac.jp [Department of Medical Safety Science, Graduate School of Pharmaceutical Science, Nagoya City University, Nagoya 267-8603 (Japan); Gonzalez, Frank J., E-mail: gonzalef@mail.nih.gov [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Komai, Michio, E-mail: mkomai@m.tohoku.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan)

    2013-11-15

    Although the aryl hydrocarbon receptor (AHR) and glucocorticoid receptor (GR) play essential roles in mammalian development, stress responses, and other physiological events, crosstalk between these receptors has been the subject of much debate. Metallothioneins are classic glucocorticoid-inducible genes that were reported to increase upon treatment with AHR agonists in rodent tissues and cultured human cells. In this study, the mechanism of human metallothionein 2A (MT2A) gene transcription activation by AHR was investigated. Cotreatment with 3-methylcholanthrene and dexamethasone, agonists of AHR and GR respectively, synergistically increased MT2A mRNA levels in HepG2 cells. MT2A induction was suppressed by RNA interference against AHR or GR. Coimmunoprecipitation experiments revealed a physical interaction between AHR and GR proteins. Moreover, chromatin immunoprecipitation assays indicated that AHR was recruited to the glucocorticoid response element in the MT2A promoter. Thus, we provide a novel mechanism whereby AHR modulates expression of human MT2A via the glucocorticoid response element and protein–protein interactions with GR. - Highlights: • Aryl hydrocarbon receptor forms a complex with glucocorticoid receptor in cells. • Human metallothionein gene is regulated by the AHR and GR interaction. • AHR–GR complex binds to glucocorticoid response element in metallothionein gene. • We demonstrated a novel transcriptional mechanism via AHR and GR interaction.

  17. Effect of various chemicals on the aldehyde dehydrogenase activity of the rat liver cytosol.

    Marselos, M; Vasiliou, V

    1991-01-01

    The cytosolic activity of aldehyde dehydrogenase (ALDH) was studied in the rat liver, after acute administration of various carcinogenic and chemically related compounds. Male Wistar rats were treated with 27 different chemicals, including polycyclic aromatic hydrocarbons, aromatic amines, nitrosamines, azo dyes, as well as with some known direct-acting carcinogens. The cytosolic ALDH activity of the liver was determined either with propionaldehyde and NAD (P/NAD), or with benzaldehyde and NADP (B/NADP). The activity of ALDH remained unaffected after treatment with 1-naphthylamine, nitrosamines and also with the direct-acting chemical carcinogens tested. On the contrary, polycyclic aromatic hydrocarbons, polychlorinated biphenyls (Arochlor 1254) and 2-naphthylamine produced a remarkable increase of ALDH. In general, the response to the effectors was disproportionate between the two types of enzyme activity, being much in favour for the B/NADP activity. This fact resulted to an inversion of the ratio B/NADP vs. P/NAD, which under constitutive conditions is lower than 1. In this respect, the most potent compounds were found to be polychlorinated biphenyls, 3-methylcholanthrene, benzo(a)pyrene and 1,2,5,6-dibenzoanthracene. Our results suggest that the B/NADP activity of the soluble ALDH is greatly induced after treatment with compounds possessing aromatic ring(s) in their molecule. It is not known, if this response of the hepatocytes is related with the process of chemical carcinogenesis. PMID:2060039

  18. Hepatic microsomal mixed-function oxidase activity in ethanol-treated hamsters and its consequences on the bioactivation of aromatic amines to mutagens.

    Ioannides, C; Steele, C M

    1986-09-01

    Male golden Syrian hamsters were maintained on ethanol-containing liquid diets for 4 weeks, corresponding to an average daily intake of 17 g/kg body wt. The p-hydroxylation of aniline was markedly enhanced by this treatment while minimal effects were seen in benzphetamine N-demethylase and ethoxyresorufin O-deethylase activities; there was no change in the microsomal levels of cytochromes P-450. Hepatic microsomal preparations from the ethanol-treated hamsters were more efficient than controls fed isocaloric diets in converting 2-aminofluorene, 4-aminobiphenyl, benzidine and 2-acetylaminofluorene into mutagens in the Salmonella mutagenicity test. The same treatment had no effect on the metabolic activation of 2-naphthylamine and even inhibited the mutagenicity of 2-aminoanthracene. No increase was seen in the activation of the two polycyclic aromatic hydrocarbons, benzo[a]pyrene and 3-methylcholanthrene to mutagens and an inhibitory effect was seen with the former. The ethanol-induced increase in the mutagenicity of 2-aminofluorene was inhibited by 2-butanol but not by the hydroxyl radical scavenger dimethylsulphoxide. It is concluded that chronic ethanol ingestion modulates the bioactivation of aromatic amines and amides to mutagens, the effect being substrate dependent. This effect of ethanol may be catalysed by unique form(s) of cytochrome P-450 whose synthesis is induced by such treatment. PMID:3021347

  19. Neoplastic transformation of human diploid fibroblast cells by chemical carcinogens

    Kakunaga, Takeo

    1978-01-01

    Cultured fibroblast cells derived from a skin biopsy sample taken from normal human adult were exposed to a potent carcinogen, 4-nitroquinoline 1-oxide. Alterations of cell growth pattern such as higher density and piling up of cells were noticed in some fractions of cultures that were successively subcultured after nitroquinoline oxide treatment. Morphologically altered cells retained this growth pattern and became established lines of transformed cells without showing the limited life-span characteristic of normal cells in culture. The transformed cells showed a higher saturation density and the ability to grow in soft agar, properties that are usually correlated with neoplastic transformation of cells in culture. Selection of preexisting transformed human cells as a mechanism of this observed transformation seemed unlikely because clones of these normal cells could also be used to assess the transforming effect of nitroquinoline oxide. Preliminary results suggest that numerous cell divisions were required for the development of the transformation after nitroquinoline oxide treatment of these human cells. When the transformed cell lines were injected subcutaneously into nude (athymic) mice, solid tumors were produced at the site of inoculation. Treatment with N-methyl-N′-nitro-N-nitrosoguanidine also induced cell transformation, in a manner similar to treatment with nitroquinoline oxide. However, transformation was not induced with (i) 4-aminoquinoline 1-oxide (a noncarcinogenic derivative of 4-nitroquinoline 1-oxide), (ii) 3-methylcholanthrene (a carcinogen that cannot be metabolically activated by the target cells employed), or (iii) the solvent dimethyl sulfoxide. Images PMID:418410

  20. Methionine restriction inhibits chemically-induced malignant transformation in the BALB/c 3T3 cell transformation assay.

    Nicken, Petra; Empl, Michael T; Gerhard, Daniel; Hausmann, Julia; Steinberg, Pablo

    2016-09-01

    High consumption of red meat entails a higher risk of developing colorectal cancer. Methionine, which is more frequently a component of animal proteins, and folic acid are members of the one carbon cycle and as such important players in DNA methylation and cancer development. Therefore, dietary modifications involving altered methionine and folic acid content might inhibit colon cancer development. In the present study, the BALB/c 3T3 cell transformation assay was used to investigate whether methionine and folic acid are able to influence the malignant transformation of mouse fibroblasts after treatment with the known tumour initiator 3-methylcholanthrene. Three different methionine concentrations (representing a -40%, a "normal" and a +40% cell culture medium concentration, respectively) and two different folic acid concentrations (6 and 20 μM) were thereby investigated. Methionine restriction led to a decrease of type III foci, while enhancement of both methionine and folic acid did not significantly increase the cell transformation rate. Interestingly, the focus-lowering effect of methionine was only significant in conjunction with an elevated folic acid concentration. In summary, we conclude that the malignant transformation of mouse fibroblasts is influenced by methionine levels and that methionine restriction could be a possible approach to reduce cancer development. PMID:27427305

  1. The effectiveness of chemical carcinogens to induce atherosclerosis in the white carneau pigeon

    The frequency of atherosclerotic lesions of the abdominal aorta has been reported to increase significantly in chickens exposed to benzo(a)pyrene and 7,12-dimethylbenz(a,h)anthracene. The present studies were performed to determine in another experimental model frequently used in atherosclerotic studies (i.e. White Carneau Pigeons) whether these and other chemical carcinogens enhance atherosclerosis. The induction and enhancement of atherosclerotic lesions were observed in pigeons treated with 7,12-dimethylbenz(a,h)anthracene, benzo(a)pyrene and 3-methylcholanthrene. The number and size of plaques in the aorta were frequently greater in pigeons treated with the higher concentrations (i.e. 100 mg/kg) of these 3 polycyclic aromatic hydrocarbons. Benzo(e)pyrene and 2,4,6-trichlorophenol were ineffective in the induction or enhancement of atherosclerosis in the pigeons. The results of the present and previous studies suggest that the polycyclic aromatic hydrocarbons (excluding benzo(e)pyrene) may be the only potential atherogens in avian atherosclerosis. This relationship may be associated with how these hydrocarbons are transported in the plasma (i.e. by lipoproteins) as demonstrated by the present distribution studies (author)

  2. A Microfabricated Platform for Generating Physiologically-Relevant Hepatocyte Zonation

    McCarty, William J.; Usta, O. Berk; Yarmush, Martin L.

    2016-05-01

    In vitro liver models have been important tools for more than 40 years for academic research and preclinical toxicity screening by the pharmaceutical industry. Hepatocytes, the highly metabolic parenchymal cells of the liver, are efficient at different metabolic chemistries depending on their relative spatial location along the sinusoid from the portal triad to the central vein. Although replicating hepatocyte metabolic zonation is vitally important for physiologically-relevant in vitro liver tissue and organ models, it is most often completely overlooked. Here, we demonstrate the creation of spatially-controlled zonation across multiple hepatocyte metabolism levels through the application of precise concentration gradients of exogenous hormone (insulin and glucagon) and chemical (3-methylcholanthrene) induction agents in a microfluidic device. Observed gradients in glycogen storage via periodic acid-Schiff staining, urea production via carbamoyl phosphatase synthetase I staining, and cell viability after exposure to allyl alcohol and acetaminophen demonstrated the in vitro creation of hepatocyte carbohydrate, nitrogen, alcohol degradation, and drug conjugation metabolic zonation. This type of advanced control system will be crucial for studies evaluating drug metabolism and toxicology using in vitro constructs.

  3. Disruption of thyroid hormone homeostasis in Ugt1a-deficient Gunn rats by microsomal enzyme inducers is not due to enhanced thyroxine glucuronidation

    Microsomal enzyme inducers (MEI) that increase UDP-glucuronosyltransferases (UGTs) are thought to increase glucuronidation of thyroxine (T4), thus reducing serum T4, and subsequently increasing thyroid stimulating hormone (TSH). Ugt1a1 and Ugt1a6 mediate T4 glucuronidation. Therefore, this experiment determined the involvement of Ugt1a enzymes in increased T4 glucuronidation, decreased serum T4, and increased TSH after MEI treatment. Male Wistar and Ugt1a-deficient Wistar (Gunn) rats were fed a control diet or diet containing pregnenolone-16α-carbonitrile (PCN; 800 ppm), 3-methylcholanthrene (3-MC; 200 ppm), or Aroclor 1254 (PCB; 100 ppm) for 7 days. Serum T4, triiodothyronine (T3), and TSH concentrations, hepatic T4/T3 glucuronidation, and thyroid histology and follicular cell proliferation were investigated. PCN, 3-MC, and PCB treatments decreased serum T4, whereas serum T3 was maintained in both Gunn and Wistar rats (except for PCB treatment). TSH was increased in Wistar and Gunn rats after PCN (130 and 277%) or PCB treatment (72 and 60%). T4 glucuronidation in Wistar rats was increased after PCN (298%), 3-MC (85%), and PCB (450%), but was extremely low in Gunn rats, and unchanged after MEI. T3 glucuronidation was increased after PCN (121%) or PCB (58%) in Wistar rats, but only PCN increased T3 glucuronidation in Gunn rats (43%). PCN treatment induced thyroid morphological changes and increased follicular cell proliferation in both strains. These data demonstrate that T4 glucuronidation cannot be increased in Ugt1a-deficient Gunn rats. Thus, the decrease in serum T4, increase in TSH, and increase in thyroid cell proliferation after MEI are not dependent on increased T4 glucuronidation, and cannot be attributed to Ugt1a enzymes.

  4. Classification of test agent-specific effects in the Syrian hamster embryo assay (pH 6.7) using infrared spectroscopy with computational analysis.

    Ahmadzai, Abdullah A; Trevisan, Júlio; Pang, Weiyi; Patel, Imran I; Fullwood, Nigel J; Bruce, Shannon W; Pant, Kamala; Carmichael, Paul L; Scott, Andrew D; Martin, Francis L

    2012-05-01

    The Syrian hamster embryo (SHE) cell transformation assay (pH 6.7) has utility in the assessment of potential chemical carcinogenicity (both genotoxic and non-genotoxic mechanisms of action). The assay uses morphological transformation as an end point and has a reported sensitivity of 87%, specificity of 83% and overall concordance of 85% with in vivo rodent bioassay data. However, the scoring of morphologically transformed SHE cells is subjective. We treated SHE cells grown on low-E reflective slides with benzo[a]pyrene, 3-methylcholanthrene, anthracene, N-nitroso-N-methylnitroguanidine, ortho-toluidine HCl, 2,4-diaminotoluene or D-mannitol for 7 days before fixation with methanol. Identified colonies were interrogated by acquiring a minimum of five infrared (IR) spectra per colony using attenuated total reflection Fourier-transform IR spectroscopy. Individual IR spectra were acquired over a spatial area of approximately 250 × 250 μm. Resultant data were analysed using Fisher's linear discriminant analysis and feature histogram algorithms to extract classifying biomarkers of test agent-specific effects or transformation in SHE cells. Clustering of spectral points suggested co-segregation or discrimination of test agent categories based on mechanism of action. Towards transformation, unifying alterations were associated with alterations in the Amide I and Amide II peaks; these were consistently major classifying biomarkers for transformed versus non-transformed SHE cells. Our approach highlights a novel method towards objectively screening and classifying SHE cells, be it to ascertain test agent treatment based on mechanism of action or transformation. PMID:22362182

  5. Deletion of Forkhead Box M1 transcription factor from respiratory epithelial cells inhibits pulmonary tumorigenesis.

    I-Ching Wang

    Full Text Available The Forkhead Box m1 (Foxm1 protein is induced in a majority of human non-small cell lung cancers and its expression is associated with poor prognosis. However, specific requirements for the Foxm1 in each cell type of the cancer lesion remain unknown. The present study provides the first genetic evidence that the Foxm1 expression in respiratory epithelial cells is essential for lung tumorigenesis. Using transgenic mice, we demonstrated that conditional deletion of Foxm1 from lung epithelial cells (epFoxm1(-/- mice prior to tumor initiation caused a striking reduction in the number and size of lung tumors, induced by either urethane or 3-methylcholanthrene (MCA/butylated hydroxytoluene (BHT. Decreased lung tumorigenesis in epFoxm1(-/- mice was associated with diminished proliferation of tumor cells and reduced expression of Topoisomerase-2alpha (TOPO-2alpha, a critical regulator of tumor cell proliferation. Depletion of Foxm1 mRNA in cultured lung adenocarcinoma cells significantly decreased TOPO-2alpha mRNA and protein levels. Moreover, Foxm1 directly bound to and induced transcription of the mouse TOPO-2alpha promoter region, indicating that TOPO-2alpha is a direct target of Foxm1 in lung tumor cells. Finally, we demonstrated that a conditional deletion of Foxm1 in pre-existing lung tumors dramatically reduced tumor growth in the lung. Expression of Foxm1 in respiratory epithelial cells is critical for lung cancer formation and TOPO-2alpha expression in vivo, suggesting that Foxm1 is a promising target for anti-tumor therapy.

  6. A study on CYP1A inhibitory action of E-2-(4'-methoxybenzylidene)-1-benzosuberone and some related chalcones and cyclic chalcone analogues

    In vivo investigation of E-2-(4'-methoxybenzylidene)-1-benzosuberone (4a) on the 7,12-dimethylbenz[a]anthracene (DMBA)-induced onco/tumor suppressor gene expressions suggested that inhibition of metabolic activation of DMBA might play a role in the observed activity of the compound. In order to explore this possible biological action we have investigated whether 4a and some of its structurally related analogues had inhibitory effects on the CYP1A enzymes. During our study 7-ethoxyresorufin O-dealkylation activity of CYP1A isoenzymes was measured in liver microsomes prepared from 3-methylcholanthrene treated male rats. Inhibition constants (Ki values) were determined by using different concentrations of 7-ethoxyresorufin and the investigated chalcones (1), E-2-benzylidene-1-indanones (2), -tetralones (3) and -benzosuberones (4). Each compound was found to be a strong competitive inhibitor of the CYP1A enzymes. Their inhibitory activity was comparable with or even higher than that of 7,8-benzoflavone, the known strong CYP1A inhibitor used as reference substance. By proper selection of the substituents on the benzylidene moiety we investigated how the inhibitory activity (Ki value) of 1-4 varied as a function of the ring size (n=0, 5, 6, 7) carbon atoms, and the nature as well as the position of the substituents. To test applicability of the previously set structural requirements for binding of xenobiotics to the CYP1A enzymes we compared some topological, physico-chemical and quantum mechanical parameters of 1-4 with 7-ethoxyresorufin and 7,8-benzoflavone, the investigated CYP1A substrate and inhibitor, respectively

  7. Induction and inhibition of NAD(P)H: quinone reductase in murine and human skin.

    Merk, H; Jugert, F; Bonnekoh, B; Mahrle, G

    1991-01-01

    The purpose of this study was to characterize the human cutaneous NAD(P)H: quinone reductase (NQR) activity by known inhibitors of different reductases and to compare it with the murine skin and liver NQR activity. This enzyme plays a major role in the defence of cells against oxygen stress because it inhibits the 1-electron reduction of quinones to semiquinones and their subsequent oxidation to quinones termed as quinone redox cycle. It belongs to the aromatic hydrocarbon-responsive (Ah) battery. This gene battery includes Cyp1a1 (cytochrome P-450 IA1), Cyp1a2 (cytochrome P-450 IA2) and Nmo-1 [NAD(P)H: quinone reductase]. In the skin cytochrome P-450 IA1-dependent activity is about 1-5% compared to the corresponding activity in the liver, whereas NQR has the same activity in skin and liver. NQR was determined in the cytoplasm of murine skin, liver, and human keratinocytes using 2,6-dichlorophenolindophenol as the substrate. The Ah-receptor binding compounds, such as coal tar constituents, or 3-methylcholanthrene induce cytochrome P-450-dependent activities such as aryl hydrocarbon hydroxylase or 7-ethoxyresorufin-O-de-ethylase and NQR, whereas butyl hydroxytoluol, which does not bind to the Ah receptor, induces only NQR. For inhibition studies several known inhibitors of dihydrodiol dehydrogenase, aldo-keto and carbonyl reductase activities were used. There was a similar pattern of inhibition of the basal and induced activity in all tissues investigated. Pyrazole, progesterone and phenobarbital did not inhibit, whereas dicoumarol, rutin and indomethacin inhibited NQR activity in murine skin and liver as well as in human keratinocytes.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1768430

  8. Changes in the host lymphocyte subsets during chemical carcinogenesis

    Changes in small lymphocyte subsets in the lymphoid organs of young C3H mice were studied following i.m. injection of a carcinogenic dose of 3-methylcholanthrene (mc). Using monoclonal anti-Lyt antibodies and a sandwich radiolabeling method with 125I-labeled rabbit anti-mouse Immunoglobulin, the lymphocyte subpopulations in the thymus, spleen, and draining lymph node were examined by radioautography. During the fifth week following the administration of the carcinogen a sharp decrease in the level of Ly-1,2+ small lymphocyte population in the thymus was noted which coincided with a considerable increase (10-fold) in the Ly-2+. During the same period, a similar increase in the Ly-2+ population was also observed in the draining. The high levels of Ly-2+ cells lasted for more than 4 weeks in the thymus while, in the draining node, they lasted for 2 weeks and dropped to normal levels (0 to 2%) simultaneously with the appearance of tumor cells identified in histological preparations. These systemic increases coincided with the appearance of macroscopic tumor nodules. The mixed lymphocyte reaction response of the draining node cells, but not of the spleen, was suppressed during the period of increased level of Ly-2+ cells. Furthermore, during this period, s.c. transplantation of a syngeneic mammary tumor in the same leg resulted in enhanced local growth as well as metastatic spread of the tumor to the lungs in mc treated mice. These findings suggest that a localized immunosuppression associated with the rise in the Ly-2+ cells may be of functional significance during carcinogen-induced tumor development

  9. Changes in the host lymphocyte subsets during chemical carcinogenesis

    Brodt, P.; Lala, P.K.

    1983-09-01

    Changes in small lymphocyte subsets in the lymphoid organs of young C3H mice were studied following i.m. injection of a carcinogenic dose of 3-methylcholanthrene (mc). Using monoclonal anti-Lyt antibodies and a sandwich radiolabeling method with /sup 125/I-labeled rabbit anti-mouse Immunoglobulin, the lymphocyte subpopulations in the thymus, spleen, and draining lymph node were examined by radioautography. During the fifth week following the administration of the carcinogen a sharp decrease in the level of Ly-1,2+ small lymphocyte population in the thymus was noted which coincided with a considerable increase (10-fold) in the Ly-2+. During the same period, a similar increase in the Ly-2+ population was also observed in the draining. The high levels of Ly-2+ cells lasted for more than 4 weeks in the thymus while, in the draining node, they lasted for 2 weeks and dropped to normal levels (0 to 2%) simultaneously with the appearance of tumor cells identified in histological preparations. These systemic increases coincided with the appearance of macroscopic tumor nodules. The mixed lymphocyte reaction response of the draining node cells, but not of the spleen, was suppressed during the period of increased level of Ly-2+ cells. Furthermore, during this period, s.c. transplantation of a syngeneic mammary tumor in the same leg resulted in enhanced local growth as well as metastatic spread of the tumor to the lungs in mc treated mice. These findings suggest that a localized immunosuppression associated with the rise in the Ly-2+ cells may be of functional significance during carcinogen-induced tumor development.

  10. Aryl hydrocarbon receptor mediates both proinflammatory and anti-inflammatory effects in lipopolysaccharide-activated microglia.

    Lee, Yi-Hsuan; Lin, Chun-Hua; Hsu, Pei-Chien; Sun, Yu-Yo; Huang, Yu-Jie; Zhuo, Jiun-Horng; Wang, Chen-Yu; Gan, Yu-Ling; Hung, Chia-Chi; Kuan, Chia-Yi; Shie, Feng-Shiun

    2015-07-01

    The aryl hydrocarbon receptor (AhR) regulates peripheral immunity; but its role in microglia-mediated neuroinflammation in the brain remains unknown. Here, we demonstrate that AhR mediates both anti-inflammatory and proinflammatory effects in lipopolysaccharide (LPS)-activated microglia. Activation of AhR by its ligands, formylindolo[3,2-b]carbazole (FICZ) or 3-methylcholanthrene (3MC), attenuated LPS-induced microglial immune responses. AhR also showed proinflammatory effects, as evidenced by the findings that genetic silence of AhR ameliorated the LPS-induced microglial immune responses and LPS-activated microglia-mediated neurotoxicity. Similarly, LPS-induced expressions of tumor necrosis factor α (TNFα) and inducible nitric oxide synthase (iNOS) were reduced in the cerebral cortex of AhR-deficient mice. Intriguingly, LPS upregulated and activated AhR in the absence of AhR ligands via the MEK1/2 signaling pathway, which effects were associated with a transient inhibition of cytochrome P450 1A1 (CYP1A1). Although AhR ligands synergistically enhance LPS-induced AhR activation, leading to suppression of LPS-induced microglial immune responses, they cannot do so on their own in microglia. Chromatin immunoprecipitation results further revealed that LPS-FICZ co-treatment, but not LPS alone, not only resulted in co-recruitment of both AhR and NFκB onto the κB site of TNFα gene promoter but also reduced LPS-induced AhR binding to the DRE site of iNOS gene promoter. Together, we provide evidence showing that microglial AhR, which can be activated by LPS, exerts bi-directional effects on the regulation of LPS-induced neuroinflammation, depending on the availability of external AhR ligands. These findings confer further insights into the potential link between environmental factors and the inflammatory brain disorders. PMID:25690886

  11. Metabolism of 4'-(9-acridinylamino)methanesulfon-m-anisidide by rat liver microsomes

    4'-(9-Acridinylamino)methanesulfon-m-anisidide (m-AMSA) is metabolized by a hepatic microsomal enzyme system composed of rat liver microsomes, a reduced nicotinamide adenine dinucleotide phosphate-generating system, cytosolic protein (or glutathione), and oxygen. Omission of any one of the components, or incubation under an atmosphere of CO or N2, results in inhibition of the reaction. Also, the addition of inhibitors of microsomal metabolism (alpha-naphthoflavone, metyrapone, or SKF 525-A) decreases m-AMSA metabolism. Metabolism of m-AMSA is more rapid with microsomes prepared from rats pretreated with phenobarbital or 3-methylcholanthrene. Two microsomal oxidation products of m-AMSA were isolated and identified as N1'-methanesulfonyl-N4'-(9-acridinyl)-3'-methoxy-2',5'-cyclohex adiene-1', 4'-dimine (m-AQDI) and 3'-methoxy-4'-(9-acridinylamino-2',5'-cyclohexadien-1'-one (m-AQI). m-AQDI reacts with glutathione to form a product previously identified in in vivo studies as the principal rat biliary metabolite and which is not cytotoxic to cultured L1210 cells. Thus, the end result of the microsomal metabolism of m-AMSA is detoxification. However, the two primary oxidation products (m-AQDI and m-AQI) are considerably more cytotoxic to L1210 cells in vitro than is m-AMSA. The concentration of m-AMSA required to produce a 5-log kill is 1.0 microgram/ml compared to 0.01 microgram/ml for m-AQDI and m-AQI. These results indicate that m-AMSA might undergo bioactivation to form the active cytotoxic species of the drug

  12. Hepatic microsomal ω-oxidation of leukotriene B4

    In this study the authors investigated the metabolism of LTB4 by rat hepatic microsomes. 3H-LTB4 (9 μM) was incubated for 20 min in the presence3 of oxygen, NADPH and liver microsomes (1.5 mg). Incubation was followed by extraction and analysis by HPLC. Metabolite identification was based on cochromatography with reference standards. At least three radioactive peaks were observed; two of which were ω-oxidation products 20-OH-LTB4 and 20-COOH-LTB4. The rate of formation of 20-OH-LTB4 (14.6 nmoles/min/mg protein) was higher than that of 20-COOH-LTB4 (2.5 nmoles/min/mg protein). The third radioactive peak remains unidentified. Product formation was negligible with boiled microsomes. LTB4 ω-hydroxylase activity required NADPH and oxygen, was linear with respect to incubation time and protein, and was maximal at pH 7.4. Enzyme activity was inhibited (>90%) by carbon monoxide, SKF 525A (1 mM), but was not affected by α-naphthoflavone. Phenobarbital (PB, 80 mg/kg for 3 days), AROCLOR 1254 (100 mg/kg for 3 days) or 3-methylcholanthrene (40 mg/kg for 3 days) administration to rats resulted in only slight (4 ω-hydroxylase activity. However, the formation of the unidentified peak was increased (>100%) by PB treatment. These results suggest that ω-oxidation is the major pathway for biotransformation of LTB4 in liver microsomes and that this reaction is mediated by cytochrome P-450

  13. Metabolism and macromolecular covalent binding of [14C]-1-nitropyrene in isolated perfused and ventilated rat lungs

    The purpose of this study was to quantitate l-nitropyrene (1-NP) metabolism and macromolecular covalent binding in the isolated perfused rat lung. Rat lungs were perfused with 2, 5, or 24 microM [14C]-1-NP for 90 min. Tidal volume and dynamic lung compliance were monitored throughout the perfusion to document the ventilatory pattern and the decay of tissue elasticity. Perfusate was sampled periodically throughout the experiment and analyzed for 1-NP metabolites with high-performance liquid chromatography. In all experiments, both dynamic lung compliance and tidal volume declined in a nearly linear manner and were approximately 60% of the initial value at the end of 90 min of perfusion. At all concentrations of [14C]-1-NP tested, less than 5 to 6% of the total amount of [14C]-1-NP added was metabolized in lungs from control and phenobarbital (PB)-treated rats. Lungs from control and PB- and 3-methylcholanthrene (3-MC)-treated rats metabolized [14C]-1-NP to oxidized, reduced, and conjugated metabolites. The major metabolites were 3-, 6-, and 8-hydroxynitropyrene. Treatment of rats with PB resulted in a 60% increase in the total metabolism of [14C]-1-NP, whereas treatment of rats with 3-MC resulted in a 10-fold increase in the rate of metabolism of [14C]-1-NP when compared to controls. Conjugate hydrolysis studies indicated that the water-soluble metabolites from lungs of control and PB- and 3-MC-treated rats consisted of hydroxynitropyrene glucuronides and hydroxynitropyrene sulfate conjugates. Quantities of 14C covalently bound to lung macromolecules after 90 min of perfusion from lungs of control and PB-treated rats were 0.06 to 0.21 nmol equivalents/g lung. However, in lungs from 3-MC-treated rats, there was a 20-fold increase in quantities of 14C covalently bound when compared to lungs from either control or PB-treated rats

  14. Studies on the metabolism of l-menthol in rats.

    Madyastha, K M; Srivatsan, V

    1988-01-01

    Metabolism of l-menthol in rats was investigated both in vivo and in vitro. Metabolites isolated and characterized from the urine of rats after oral administration (800 mg/kg of body weight/day) of l-menthol were the following: p-menthane-3,8-diol (II), p-menthane-3,9-diol (III), 3,8-oxy-p-menthane-7-carboxylic acid (IV), and 3,8-dihyroxy-p-menthane-7-carboxylic acid (V). In vivo, the major urinary metabolites were compounds II and V. Repeated oral administration (800 mg/kg of body weight/day) of l-menthol to rats for 3 days resulted in the increase of both liver microsomal cytochrome P-450 content and NADPH-cytochrome c reductase activity by nearly 80%. Further treatment (for 7 days total) reduced their levels considerably, although the levels were still higher than the control values. Both cytochrome b5 and NADH-cytochrome c reductase levels were not changed during the 7 days of treatment. Rat liver microsomes readily converted l-menthol to p-menthane-3,8-diol (II) in the presence of NADPH and O2. This activity was significantly higher in microsomes obtained from phenobarbital (PB)-induced rats than from control microsomal preparations, whereas 3-methylcholanthrene (3-MC)-induced microsomes failed to convert l-menthol to compound II in the presence of NADPH and O2. l-Menthol elicited a type I spectrum with control (Ks = 60.6 microM) and PB-induced (Ks = 32.3 microM) microsomes whereas with 3MC-induced microsomes it produced a reverse type I spectrum.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2906604

  15. Embryonic turkey liver: activities of biotransformation enzymes and activation of DNA-reactive carcinogens

    Perrone, Carmen E.; Duan, Jian Dong; Jeffrey, Alan M.; Williams, Gary M. [New York Medical College, Department of Pathology, Valhalla (United States); Ahr, Hans-Juergen; Schmidt, Ulrich [Bayer AG, Institute of Toxicology, Wuppertal (Germany); Enzmann, Harald H. [Federal Institute for Drugs and Medical Devices, Bonn (Germany)

    2004-10-01

    Avian embryos are a potential alternative model for chemical toxicity and carcinogenicity research. Because the toxic and carcinogenic effects of some chemicals depend on bioactivation, activities of biotransformation enzymes and formation of DNA adducts in embryonic turkey liver were examined. Biochemical analyses of 22-day in ovoturkey liver post-mitochondrial fractions revealed activities of the biotransformation enzymes 7-ethoxycoumarin de-ethylase (ECOD), 7-ethoxyresorufin de-ethylase (EROD), aldrin epoxidase (ALD), epoxide hydrolase (EH), glutathione S-transferase (GST), and UDP-glucuronyltransferase (GLUT). Following the administration of phenobarbital (24 mg/egg) on day 21, enzyme activities of ECOD, EROD, ALD, EH and GLUT, but not of GST, were increased by two-fold or higher levels by day 22. In contrast, acute administration of 3-methylcholanthrene (5 mg/egg) induced only ECOD and EROD activities. Bioactivation of structurally diverse pro-carcinogens was also examined using {sup 32}P-postlabeling for DNA adducts. In ovoexposure of turkey embryos on day 20 of gestation to 2-acetylaminofluorene (AAF), 4,4'-methylenebis(2-chloroaniline) (MOCA), benzo[a]pyrene (BaP), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) resulted in the formation of DNA adducts in livers collected by day 21. Some of the DNA adducts had {sup 32}P-postlabeling chromatographic migration patterns similar to DNA adducts found in livers from Fischer F344 rats exposed to the same pro-carcinogens. We conclude that 21-day embryonic turkey liver is capable of chemical biotransformation and activation of genotoxic carcinogens to form DNA adducts. Thus, turkey embryos could be utilized to investigate potential chemical toxicity and carcinogenicity. (orig.)

  16. Responsiveness of cerebral and hepatic cytochrome P450s in rat offspring prenatally exposed to lindane

    ABSTRACT: Prenatal exposure to low doses of lindane has been shown to affect the ontogeny of xenobiotic metabolizing cytochrome P450s (CYPs), involved in the metabolism and neurobehavioral toxicity of lindane. Attempts were made in the present study to investigate the responsiveness of CYPs in offspring prenatally exposed to lindane (0.25 mg/kg b. wt.; 1/350th of LD50; p. o. to mother) when challenged with 3-methylcholanthrene (MC) or phenobarbital (PB), inducers of CYP1A and 2B families or a sub-convulsant dose of lindane (30 mg/kg b. wt., p. o.) later in life. Prenatal exposure to lindane was found to produce an increase in the mRNA and protein expression of CYP1A1, 1A2, 2B1, 2B2 isoforms in brain and liver of the offspring at postnatal day 50. The increased expression of the CYPs in the offspring suggests the sensitivity of the CYPs during postnatal development, possibly, to low levels of lindane, which may partition into mother's milk. A higher increase in expression of CYP1A and 2B isoenzymes and their catalytic activity was observed in animals pretreated prenatally with lindane and challenged with MC (30 mg/kg, i. p. x 5 days) or PB (80 mg/kg, i. p. x 5 days) when young at age (approx. 7 weeks) compared to animals exposed to MC or PB alone. Further, challenge of the control and prenatally exposed offspring with a single sub-convulsant dose of lindane resulted in an earlier onset and increased incidence of convulsions in the offspring prenatally exposed to lindane have demonstrated sensitivity of the CYPs in the prenatally exposed offspring. Our data assume significance as the subtle changes in the expression profiles of hepatic and cerebral CYPs in rat offspring during postnatal development could modify the adult response to a later exposure to xenobiotics

  17. Metabolic effects of growth factors and polycyclic aromatic hydrocarbons on cultured human placental cells of early and late gestation

    The metabolic effects of epidermal growth factor (EGF), insulin, insulin-like growth factor-I (IGF-I), and IGF-II were determined on human placental cells in monolayer culture obtained from early gestation (less than 20 weeks) and late gestation (38-42 weeks). Parameters studied were uptake of aminoisobutyric acid (AIB), uptake of 3-O-methylglucose and [3H]thymidine incorporation into cell protein. Since benzo[alpha]pyrene (BP) inhibits EGF binding and autophosphorylation in cultured human placental cells, particularly in early gestation, we also studied the effect of benzo[alpha]pyrene and other polycyclic aromatic hydrocarbons (PAHs) on EGF-mediated AIB uptake. The metabolic effects of EGF, insulin, and the IGFs in cultured human placental cells varied with gestational age and the growth factor studied. All three classes of growth factors stimulated AIB uptake in both early and late gestation at concentrations from 10-100 micrograms/L, well within a physiological range. However, insulin stimulation of AIB uptake was maximal at a high concentration in both early and late gestation cells, suggesting an action via type 1 IGF receptors rather than via insulin receptors. EGF stimulated 3-O-methylglucose uptake only in term placental cells. No significant stimulation of [3H]thymidine incorporation by any of the growth factors tested was seen with either early or late gestation cells. The effect of PAHs on AIB uptake by cultured placental cells was variable. BP alone stimulated AIB uptake by both very early and late gestation cells and enhanced EGF-stimulated AIB uptake. alpha-naphthoflavone alone inhibited AIB uptake at all gestational ages and inhibited EGF-stimulated AIB uptake. beta-Naphthoflavone and 3-methylcholanthrene minimally inhibited AIB uptake by early gestation cells and did not modify EGF-stimulated uptake at any gestational period

  18. A Novel Antihepatitis Drug, Bicyclol, Prevents Liver Carcinogenesis in Diethylnitrosamine-Initiated and Phenobarbital-Promoted Mice Tumor Model

    Hua Sun

    2012-01-01

    Full Text Available Bicyclol, an antihepatitis drug developed by Chinese scientists, has been shown to prevent the malignant transformation induced by 3-methylcholanthrene and 12-O-tetradecanoylphorbol-13-acetate in WB-F344 rat liver epithelial cells. This study provides further evidence on its role as a chemopreventive agent in experimental mice with diethylnitrosamine- (DEN- initiated and phenobarbital- (PB- promoted liver carcinoma. Liver tissue and serum were collected. In the two-stage model of hepatocarcinogenesis in mice, oral administration of bicyclol (100, 200 mg/kg before DEN injection showed significant reduction in the incidence of hepatocellular foci, nodules, or carcinoma. Histopathological examination revealed that there was no hepatocellular carcinoma (HCC and hepatoma formation in the mice pretreated with bicyclol (200 mg/kg at week 20, while the mice treated with DEN/PB developed 33.3% HCC and 55.6% hepatoma. Furthermore, the serum levels of alanine aminotransferase (ALT, alkaline phosphatase (ALP, and α-fetal protein (AFP in serum significantly increased in the DEN/PB model group in comparison with the control group. Pretreatment with bicyclol showed a marked reduction in the above condition. Bicyclol also decreased the expression of AFP and proliferating cell nuclear antigen level in the liver tissue and attenuated the decrease in body weight. In this study, we also found that 10 weeks after stopping the administration of PB and drugs, the control and bicyclol-treated (200 mg/kg animals showed no HCC and hepatoma formation at the time of termination whereas DEN/PB-induced mice developed 100% hepatoma and 50% HCC. These results further indicate that bicyclol has the chemopreventive potential for liver carcinogenesis induced by carcinogens.

  19. Development of basal and induced aryl hydrocarbon (benzo[a]pyrene) hydroxylase activity in the chicken embryo in ovo.

    Hamilton, J W; Denison, M S; Bloom, S E

    1983-06-01

    The development of the hepatic microsomal mixed-function oxidase system was studied to determine the basal level of embryonic enzyme activity and the inducibility of this system throughout growth and differentiation. Chicken embryo livers were assayed for basal and inducible hepatic aryl hydrocarbon hydroxylase (AHHase; designated elsewhere as AHH) activity from the first appearance of the liver as a discrete organ at 5 days of incubation (DI) through day 10 after hatching. In addition, whole-embryo and viscera preparations were assayed at 3 and 4 DI. Basal AHHase activity was equal to or greater than adult levels from 3 DI through hatching in all preparations (approximately 0.3-0.5 nmol/min per mg). A 3-fold increase in basal activity above adult values occurred at hatching. The onset of inducibility in chicken embryo liver between 5 and 6 DI was concomitant with hepatocyte differentiation. A developmental profile of 24-hr 3,4,3', 4'-tetrachlorobiphenyl-induced AHHase activity showed 15- to 30-fold induction over controls from 7 DI through day 10 after hatching, with a maximum of 15 nmol/min per mg at 14 DI and day 1 after hatching, a specific activity greater than 50% greater than maximal induction in the adult. Embryonic AHHase activity was also induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin, 3-methylcholanthrene, beta-naphthoflavone, and sodium phenobarbital. Induction kinetics throughout embryonic development were similar to those reported for the adult chicken and other animals. These findings demonstrate development of a mixed-function oxidase system in very early embryogenesis and then in the liver as it differentiates. Liver AHHase activity is inducible throughout development and perinatally but such activity is under strict developmental regulation. The chicken embryo has adult levels of AHHase activity which would be sufficient to achieve metabolic activation of promutagens/carcinogens before and after hepatocyte differentiation. PMID:6407011

  20. Effects of 12-O-tetradecanoylphorbol-13-acetate on the incorporation of labelled precursors into RNA, DNA and protein in epidermis, dermis and subcutis from precancerous mouse skin with reference to enhanced tumorigenesis

    The effects of a single application of 1.8 nmol 12-O-tetradecanoylphorbol-13-acetate (TPA) on precursor incorporation into RNA, DNA and protein in the epidermis, dermis and subcutis from 3-methylcholanthrene (MCA) injected precancerous mouse skin were studied at various time points between 3 and 96 h. In the precancerous tissues, the rates of incorporation of [3H]uridine into RNA did not alter appreciably from those in the control tissues; while the rates of [3H]methylthymidine incorporation into DNA were elevated with peaks appearing between 6 and 12 h, at 24 h and at 72 h in epidermis, dermis and subcutis. The rate of incorporation of [14C]leucine into protein was markedly elevated in all the three tissues which showed 3-4 sharp peaks. The maximum stimulation ranged between 14 and 20 times that of the control. A single application of TPA to the precancerous mouse skin induced early stimulation of precursor incorporation into all the three macromolecules in epidermis, dermis and subcutis. The increased stimulation was maintained for 36-72 h. The patterns of incorporation of [3H]methylthymidine into DNA gave rise to 2-3 peaks of elevated uptake in each tissue up to 36-48 h. A lowered rate of DNA synthesis between 48 and 60 h was followed by a peak at 72 h. In each group, epidermal mitotic activity correlated well with spurts of precursor incorporation into cellular DNA. The observations indicate that TPA recruits more cells into the DNA synthetic phase and accelerates selective growth of preneoplastic cells during tumor progression

  1. The product of the cph oncogene is a truncated, nucleotide-binding protein that enhances cellular survival to stress.

    Velasco, J A; Avila, M A; Notario, V

    1999-01-21

    Cph was isolated from neoplastic Syrian hamster embryo fibroblasts initiated by 3-methylcholanthrene (MCA), and was shown to be a single copy gene in the hamster genome, conserved from yeast to human cells, expressed in fetal cells and most adult tissues, and acting synergistically with H-ras in the transformation of murine NIH3T3 fibroblasts. We have now isolated Syrian hamster full-length cDNAs for the cph oncogene and proto-oncogene. Nucleotide sequence analysis revealed that cph was activated in MCA-treated cells by a point-mutational deletion at codon 214, which caused a shift in the normal open reading frame (ORF) and brought a translation termination codon 33 amino acids downstream. While proto-cph encodes a protein (pcph) of 469 amino acids, cph encodes a truncated protein (cph) of 246 amino acids with a new, hydrophobic C-terminus. Similar mechanisms activated cph in other MCA-treated Syrian hamster cells. The cph and proto-cph proteins have partial sequence homology with two protein families: GDP/GTP exchange factors and nucleotide phosphohydrolases. In vitro translated, gel-purified cph proteins did not catalyze nucleotide exchange for H-ras, but were able to bind nucleotide phosphates, in particular ribonucleotide diphosphates such as UDP and GDP. Steady-state levels of cph mRNA increased 6.7-fold in hamster neoplastic cells, relative to a 2.2-fold increase in normal cells, when they were subjected to a nutritional stress such as serum deprivation. Moreover, cph-transformed NIH3T3 cells showed increased survival to various forms of stress (serum starvation, hyperthermia, ionizing radiation), strongly suggesting that cph participates in cellular mechanisms of response to stress. PMID:9989819

  2. Chimeric Mice with Humanized Livers: A Unique Tool for in Vivo and in Vitro Enzyme Induction Studies

    Masakazu Kakuni

    2013-12-01

    Full Text Available We performed in vivo and in vitro studies to determine the induction of human cytochrome P450 (CYP using chimeric mice with humanized liver (PXB-mice® and human hepatocytes isolated from the PXB-mice (PXB-cells, which were derived from the same donor. For the in vivo study, PXB-mice were injected with 3-methylcholanthrene (3-MC, 2 or 20 mg/kg or rifampicin (0.1 or 10 mg/kg for four days. For the in vitro study, PXB-cells were incubated with 3-MC (10, 50, or 250 ng/mL or with rifampicin (5 or 25 μg/mL. The CYP1A1 and 1A2, and CYP3A4 mRNA expression levels increased significantly in the PXB-mouse livers with 20 mg/kg of 3-MC (Cmax, 12.2 ng/mL, and 10 mg/kg rifampicin (Cmax, 6.9 µg/mL, respectively. The CYP1A1 mRNA expression level increased significantly in PXB-cells with 250 ng/mL of 3-MC, indicating lower sensitivity than in vivo. The CYP1A2 and CYP3A4 mRNA expression levels increased significantly with 50 ng/mL of 3-MC, and 5 μg/mL of rifampicin, respectively, which indicated that the sensitivities were similar between in vivo and in vitro studies. In conclusion, PXB-mice and PXB-cells provide a robust model as an intermediate between in vivo and in vitro human metabolic enzyme induction studies.

  3. Metabolism of 1- and 2-naphthylamine in isolated rat hepatocytes.

    Orzechowski, A; Schrenk, D; Bock, K W

    1992-12-01

    The liver probably plays a major role in the metabolic activation of the bladder carcinogen 2-naphthylamine (2-NA) and in the inactivation of the non-carcinogenic isomer 1-naphthylamine (1-NA). However, metabolic profiles of these compounds (including primary metabolites and directly determined conjugates) in hepatocytes are not available. Therefore metabolism of 1- and 2-NA was compared in freshly isolated hepatocytes from 3-methylcholanthrene (MC)-treated and untreated rats. At 10 microM, 2-NA was found to be mainly N-acetylated (66% of total metabolites after 1 h incubation) and N-glucuronidated (19%). Minor pathways led to C-oxidation (7%) and N-oxidation (3%; 2% present as the N-glucuronide). In hepatocytes from MC-treated rats total metabolism was slightly affected (1.5-fold increase). However, C- and N-oxidation were markedly increased (63 and 18% respectively), while N-acetylation and N-glucuronidation were diminished (5 and 2% respectively). Similar experiments were carried out with 1-NA. Its N-glucuronide was the predominant metabolite (68%) followed by the N-acetylated compound (15%) while C-oxidation was low and N-oxidized metabolites could not be detected, even after induction. The results demonstrate that MC treatment markedly shifted 2-NA metabolism from N-acetylation and N-glucuronidation to N- and C-oxidation. In the case of 1-NA metabolism extensive N-glucuronidation together with the lack of N-oxidation may prevent carcinogenesis. PMID:1473229

  4. Monocrotophos induces the expression and activity of xenobiotic metabolizing enzymes in pre-sensitized cultured human brain cells.

    Vinay K Tripathi

    Full Text Available The expression and metabolic profile of cytochrome P450s (CYPs is largely missing in human brain due to non-availability of brain tissue. We attempted to address the issue by using human brain neuronal (SH-SY5Y and glial (U373-MG cells. The expression and activity of CYP1A1, 2B6 and 2E1 were carried out in the cells exposed to CYP inducers viz., 3-methylcholanthrene (3-MC, cyclophosphamide (CPA, ethanol and known neurotoxicant- monocrotophos (MCP, a widely used organophosphorous pesticide. Both the cells show significant induction in the expression and CYP-specific activity against classical inducers and MCP. The induction level of CYPs was comparatively lower in MCP exposed cells than cells exposed to classical inducers. Pre-exposure (12 h of cells to classical inducers significantly added the MCP induced CYPs expression and activity. The findings were concurrent with protein ligand docking studies, which show a significant modulatory capacity of MCP by strong interaction with CYP regulators-CAR, PXR and AHR. Similarly, the known CYP inducers- 3-MC, CPA and ethanol have also shown significantly high docking scores with all the three studied CYP regulators. The expression of CYPs in neuronal and glial cells has suggested their possible association with the endogenous physiology of the brain. The findings also suggest the xenobiotic metabolizing capabilities of these cells against MCP, if received a pre-sensitization to trigger the xenobiotic metabolizing machinery. MCP induced CYP-specific activity in neuronal cells could help in explaining its effect on neurotransmission, as these CYPs are known to involve in the synthesis/transport of the neurotransmitters. The induction of CYPs in glial cells is also of significance as these cells are thought to be involved in protecting the neurons from environmental insults and safeguard them from toxicity. The data provide better understanding of the metabolizing capability of the human brain cells against

  5. IL-13 but not IL-4 signaling via IL-4Rα protects mice from papilloma formation during DMBA/TPA two-step skin carcinogenesis

    Interleukin 4 (IL-4) was shown to be tumor-promoting in full carcinogenesis studies using 3-methylcholanthrene (MCA). Because heretofore the role of IL-4 in DMBA/TPA (9,10-dimethyl-1,2-benz-anthracene/12-O-tetradecanoylphorbol-13-acetate) two-stage carcinogenesis was not studied, we performed such experiments using either IL-4−/− or IL-4Rα−/− mice. We found that IL-4Rα−/− but not IL-4−/− mice have enhanced papilloma formation, suggesting that IL-13 may be involved. Indeed, IL-13−/− mice developed more papillomas after exposure to DMBA/TPA than their heterozygous IL-13-competent littermate controls. However, when tested in a full carcinogenesis experiment, exposure of mice to 25 μg of MCA, both IL-13−/− and IL-13+/− mice led to the same incidence of tumors. While IL-4 enhances MCA carcinogenesis, it does not play a measurable role in our DMBA/TPA carcinogenesis experiments. Conversely, IL-13 does not affect MCA carcinogenesis but protects mice from DMBA/TPA carcinogenesis. One possible explanation is that IL-4 and IL-13, although they share a common IL-4Rα chain, regulate signaling in target cells differently by employing distinct JAK/STAT-mediated signaling pathways downstream of IL-13 or IL-4 receptor complexes, resulting in different inflammatory transcriptional programs. Taken together, our results indicate that the course of DMBA/TPA- and MCA-induced carcinogenesis is affected differently by IL-4 versus IL-13-mediated inflammatory cascades

  6. Creatine supplementation with methylglyoxal: a potent therapy for cancer in experimental models.

    Pal, Aparajita; Roy, Anirban; Ray, Manju

    2016-08-01

    The anti-cancer effect of methylglyoxal (MG) is now well established in the literature. The main aim of this study was to investigate the effect of creatine as a supplement in combination with MG both in vitro and in vivo. In case of the in vitro studies, two different cell lines, namely MCF-7 (human breast cancer cell line) and C2C12 (mouse myoblast cell line) were chosen. MG in combination with creatine showed enhanced apoptosis as well as higher cytotoxicity in the breast cancer MCF-7 cell line, compared to MG alone. Pre-treatment of well-differentiated C2C12 myotubes with cancerogenic 3-methylcholanthrene (3MC) induced a dedifferentiation of these myotubes towards cancerous cells (that mimic the effect of 3MC observed in solid fibro-sarcoma animal models) and subsequent exposure of these induced cancer cells with MG proved to be cytotoxic. Thus, creatine plus ascorbic acid enhanced the anti-cancer effects of MG. In contrast, when normal C2C12 muscle cells or myotubes (mouse normal myoblast cell line) were treated with MG or MG plus creatine and ascorbic acid, no detrimental effects were seen. This indicated that cytotoxic effects of MG are specifically limited towards cancer cells and are further enhanced when MG is used in combination with creatine and ascorbic acid. For the in vivo studies, tumors were induced by injecting Sarcoma-180 cells (2 × 10(6) cells/mouse) in the left hind leg. After 7 days of tumor inoculation, treatments were started with MG (20 mg/kg body wt/day, via the intravenous route), with or without creatine (150 mg/kg body wt/day, fed orally) and ascorbic acid (50 mg/kg body wt/day, fed orally) and continued for 10 consecutive days. Significant regression of tumor size was observed when Sarcoma-180 tumor-bearing mice were treated with MG and even more so with the aforesaid combination. The creatine-supplemented group demonstrated better overall survival in comparison with tumor-bearing mice without creatine. In conclusion, it may be

  7. Transcriptomic analysis of pathways regulated by toll-like receptor 4 in a murine model of chronic pulmonary inflammation and carcinogenesis

    Grissom Sherry F

    2009-11-01

    Full Text Available Abstract Background Therapeutic strategies exist for human pulmonary neoplasia, however due to the heterogeneity of the disease, most are not very effective. The innate immunity gene, toll-like receptor 4 (TLR4, protects against chronic pulmonary inflammation and tumorigenesis in mice, but the mechanism is unclear. This study was designed to identify TLR4-mediated gene expression pathways that may be used as prognostic indicators of susceptibility to lung tumorigenesis in mice and provide insight into the mechanism. Methods Whole lung mRNA was isolated from C.C3H-Tlr4Lps-d (BALBLps-d; Tlr4 mutant and BALB/c (Tlr4 normal mice following butylated hydroxytoluene (BHT-treatment (four weekly ip. injections; 150-200 mg/kg/each; "promotion". mRNA from micro-dissected tumors (adenomas and adjacent uninvolved tissue from both strains were also compared 27 wks after a single carcinogen injection (3-methylcholanthrene (MCA, 10 μg/g; "control" or followed by BHT (6 weekly ip. injections; 125-200 mg/kg/each; "progression". Bronchoalveolar lavage fluid was analyzed for inflammatory cell content and total protein determination, a marker of lung hyperpermeability; inflammation was also assessed using immunohistochemical staining for macrophages (F4/80 and lymphocytes (CD3 in mice bearing tumors (progression. Results During promotion, the majority of genes identified in the BALBLps-d compared to BALB/c mice (P Ereg, secreted phosphoprotein 1(Spp1, which can lead to cell growth and eventual tumor development. Inflammation was significantly higher in BALBLps-d compared to BALB/c mice during progression, similar to the observed response during tumor promotion in these strains. Increases in genes involved in signaling through the EGFR pathway (e.g. Ereg, Spp1 were also observed during progression in addition to continued inflammation, chemotactic, and immune response gene expression in the BALBLps-d versus BALB/c mice (P Conclusion This transcriptomic study

  8. Microsomal biotransformation of benzo[ghi]perylene, a mutagenic polycyclic aromatic hydrocarbon without a "classic" bay region.

    Platt, Karl L; Grupe, Stefanie

    2005-04-01

    Carcinogenic polycyclic aromatic hydrocarbons (PAH), e.g., benzo[a]pyrene (BaP), possess a bay region comprising an ortho-fused benzene ring. Benzo[ghi]perylene (BghiP) represents the group of PAHs lacking such a "classic" bay region and hence cannot be metabolically converted like BaP to bay region dihydrodiol epoxides considered as ultimate mutagenic and carcinogenic metabolites of PAH. BghiP exhibits bacterial mutagenicity in strains TA98 (1.3 his(+)-revertant colonies/nmol) and TA100 (4.3 his(+)-revertant colonies/nmol) of Salmonella typhimurium after metabolic activation by the postmitochondrial hepatic fraction of CD rats treated with 3-methylcholanthrene. Inhibition of microsomal epoxide hydrolase (mEH) with 1,1,1-trichloro-2-propene oxide raised the bacterial mutagenicity of BghiP in TA98 almost 4-fold indicating arene oxides as ultimate mutagens. To confirm this assumption, the biotransformation of BghiP was elucidated. Incubation of BghiP with liver microsomes of CD rats treated with Aroclor 1254 yielded 17 ethyl acetate extractable metabolic products. Twelve metabolites were identified by a combination of chromatographic, spectroscopic, and biochemical methods. The microsomal biotransformation of BghiP proceeds by two pathways: Pathway I starts with the monooxygenase attack at the 7-position leading to the 7-phenol, which is transformed to the 7,8- and 7,10-diphenols followed by oxidation to the 7,8- and 7,10-quinones. On pathway II, the K regions of BghiP are successively converted to arene oxides yielding the indirectly identified 3,4-oxide and the 3,4,11,12-bisoxides. Enzymatic hydrolysis of the 3,4-oxide leads to the trans-3,4-dihydrodiol, which is oxidized to the 3,4-quinone. Similarly, the trans-3,4-trans-11,12-bisdihydrodiols and the trans-3,4-dihydrodiol 11,12-quinone are generated from the 3,4,11,12-bisoxides. The trans-3,4-dihydrodiol and the trans-3,4-trans-11,12-bisdihydrodiols are preferentially formed as R,R and R,R,R,R enantiomers

  9. UVA Photoirradiation of Oxygenated Benz[a]anthracene and 3-Methylcholanthene - Generation of Singlet Oxygen and Induction of Lipid Peroxidation

    Diógenes Herreño Sáenz

    2008-03-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are widespread genotoxic environmental pollutants and potentially pose a health risk to humans. Although the biological and toxicological activities, including metabolism, mutagenicity, and carcinogenicity, of PAHs have been thoroughly studied, their phototoxicity and photo-induced biological activity have not been well examined. We have long been interested in phototoxicity of PAHs and their derivatives induced by irradiation with UV light. In this paper we report the photoirradiation of a series of oxygenated benz[a]anthracene (BA and 3-methylcholanthene (3-MC by UVA light in the presence of a lipid, methyl linoleate. The studied PAHs include 2-hydroxy-BA (2-OH-BA, 3-hydroxy-BA (3-OH-BA, 5-hydroxymethyl-BA (5-CH2OH-BA, 7-hydroxymethyl-BA (7-CH2OH-BA, 12-hydroxymethyl-BA (12-CH2OH-BA, 7-hydroxymethyl-12-methyl-BA (7-CH2OH-12-MBA, 5-formyl-BA (5-CHO-BA, BA 5,6-cis-dihydrodiol (BA 5,6-cis-diol, 1-hydroxy-3- methylcholanthene (1-OH-3-MC, 1-keto-3-methylcholanthene (1-keto-3-MC, and 3-MC 1,2-diol. The results indicate that upon photoirradiation by UVA at 7 and 21 J/cm2, respectively all these compounds induced lipid peroxidation and exhibited a relationship between the dose of the light and the level of lipid peroxidation induced. To determine whether or not photoirradiation of these compounds by UVA light produces ROS, an ESR spin-trap technique was employed to provide direct evidence. Photoirradiation of 3-keto-3-MC by UVA (at 389 nm in the presence of 2,2,6,6-tetramethylpiperidine (TEMP, a specific probe for singlet oxygen, resulted in the formation of TEMPO, indicating that singlet oxygen was generated. These overall results suggest that UVA photoirradiation of oxygenated BA and 3-methylcholanthrene generates singlet oxygen, one of the reactive oxygen species (ROS, which induce lipid peroxidation.

  10. Phenobarbital induction of cytochromes P-450. High-level long-term responsiveness of primary rat hepatocyte cultures to drug induction, and glucocorticoid dependence of the phenobarbital response.

    Waxman, D J; Morrissey, J J; Naik, S; Jauregui, H O

    1990-01-01

    The induction of hepatic cytochromes P-450 by phenobarbital (PB) was studied in rat hepatocytes cultured for up to 5 weeks on Vitrogen-coated plates in serum-free modified Chee's medium then exposed to PB (0.75 mM) for an additional 4 days. Immunoblotting analysis indicated that P-450 forms PB4 (IIB1) and PB5 (IIB2) were induced dramatically (greater than 50-fold increase), up to levels nearly as high as those achieved in PB-induced rat liver in vivo. The newly synthesized cytochrome P-450 was enzymically active, as shown by the major induction of the P-450 PB4-dependent steroid 16 beta-hydroxylase and pentoxyresorufin O-dealkylase activities in the PB-induced hepatocyte microsomes (up to 90-fold increase). PB induction of these P-450s was markedly enhanced by the presence of dexamethasone (50 nM-1 microM), which alone was not an affective inducing agent, and was inhibited by greater than 90% by 10% fetal bovine serum. The PB response was also inhibited (greater than 85%) by growth hormone (250 ng/ml), indicating that this hormone probably acts directly on the hepatocyte when it antagonizes the induction of P-450 PB4 in intact rats. In untreated hepatocytes, P-450 RLM2 (IIA2), P-450 3 (IIA1) and NADPH P-450 reductase levels were substantially maintained in the cultures for 10-20 days. The latter two enzymes were also inducible by PB to an extent (3-4 fold elevation) that is comparable with that observed in the liver in vivo. Moreover, P-450c (IA1) and P-450 3 (IIA1) were highly inducible by 3-methylcholanthrene (5 microM; 48 h exposure) even after 3 weeks in culture. In contrast, the male-specific pituitary-regulated P-450 form 2c (IIC11) was rapidly lost upon culturing the hepatocytes, suggesting that supplementation of appropriate hormonal factors may be necessary for its expression. The present hepatocyte culture system exhibits a responsiveness to drug inducers that is qualitatively and quantitatively comparable with that observed in vivo, and should prove

  11. Metabolism of UV-filter benzophenone-3 by rat and human liver microsomes and its effect on endocrine-disrupting activity

    Watanabe, Yoko, E-mail: y-watanabe@nichiyaku.ac.jp [Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Nihon Pharmaceutical University, Komuro 10281, Ina-machi, Saitama 362-0806 (Japan); Kojima, Hiroyuki; Takeuchi, Shinji [Hokkaido Institute of Public Health, Kita-19, Nishi-12, Kita-ku, Sapporo 060-0819 (Japan); Uramaru, Naoto [Nihon Pharmaceutical University, Komuro 10281, Ina-machi, Saitama 362-0806 (Japan); Sanoh, Seigo [Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Sugihara, Kazumi [Faculty of Pharmaceutical Science, Hiroshima International University, Koshingai 5-1-1, Kure, Hiroshima 737-0112 (Japan); Kitamura, Shigeyuki [Nihon Pharmaceutical University, Komuro 10281, Ina-machi, Saitama 362-0806 (Japan); Ohta, Shigeru [Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan)

    2015-01-15

    Benzophenone-3 (2-hydroxy-4-methoxybenzophenone; BP-3) is widely used as sunscreen for protection of human skin and hair from damage by ultraviolet (UV) radiation. In this study, we examined the metabolism of BP-3 by rat and human liver microsomes, and the estrogenic and anti-androgenic activities of the metabolites. When BP-3 was incubated with rat liver microsomes in the presence of NADPH, 2,4,5-trihydroxybenzophenone (2,4,5-triOH BP) and 3-hydroxylated BP-3 (3-OH BP-3) were newly identified as metabolites, together with previously detected metabolites 5-hydroxylated BP-3 (5-OH BP-3), a 4-desmethylated metabolite (2,4-diOH BP) and 2,3,4-trihydroxybenzophenone (2,3,4-triOH BP). In studies with recombinant rat cytochrome P450, 3-OH BP-3 and 2,4,5-triOH BP were mainly formed by CYP1A1. BP-3 was also metabolized by human liver microsomes and CYP isoforms. In estrogen reporter (ER) assays using estrogen-responsive CHO cells, 2,4-diOH BP exhibited stronger estrogenic activity, 2,3,4-triOH BP exhibited similar activity, and 5-OH BP-3, 2,4,5-triOH BP and 3-OH BP-3 showed lower activity as compared to BP-3. Structural requirements for activity were investigated in a series of 14 BP-3 derivatives. When BP-3 was incubated with liver microsomes from untreated rats or phenobarbital-, 3-methylcholanthrene-, or acetone-treated rats in the presence of NADPH, estrogenic activity was increased. However, liver microsomes from dexamethasone-treated rats showed decreased estrogenic activity due to formation of inactive 5-OH BP-3 and reduced formation of active 2,4-diOH BP. Anti-androgenic activity of BP-3 was decreased after incubation with liver microsomes. - Highlights: • Metabolic modification of the endocrine-disrupting activity of BP-3 was examined. • 2,4,5-TriOH BP and 3-OH BP-3 were identified as new BP-3 metabolites. • 2,4-DiOH BP and 2,3,4-triOH BP exhibited high or similar estrogenic activities. • Estrogenic activity of BP-3 was enhanced by incubation with rat liver

  12. Regulation of FoxO transcription factors by environmental NO(x). Influence of metal ions and polycyclic aromatic hydrocarbons; Regulation von FoxO-Transkriptionsfaktoren durch Umweltnoxen. Einfluss von Metallionen und polyzyklischen aromatischen Kohlenwasserstoffen

    Eckers, Anna

    2009-12-15

    FoxO transcription factors are crucial modulators of various cellular processes, controlling the expression of target genes such as those coding for manganese superoxide dismutase (MnSOD) and selenoprotein P (SeP), thereby supporting defense against oxidative stress. Environmental stimuli such as heavy metal ions and polycyclic aromatic hydrocarbons (PAH) modulate signaling pathways both by interaction with proteins or by inducing the generation of reactive oxygen species (ROS). Exposure of hepatoma cells to nickel ions at subcytotoxic doses did not translate into modulation of FoxO activity despite an activation of the Ser/Thr-kinase Akt. The cellular response to nickel ions under these conditions is most likely independent of the formation of ROS, since there were no increased levels of glutathione disulfide detectable. FoxO activity was then found to be modulated in response to exposure of cells to PAH or the tryptophan photoproduct FICZ. Both PAH and FICZ caused an increased activity of a FoxO-responsive promoter construct as well as of glucose 6-phosphatase promoter activity. In contrast, the activities of promoters of genes coding for MnSOD or SeP were decreased in response to exposure to the PAH 3-methylcholanthrene (3-MC). In line with the promoter effects, 3-MC also decreased steady-state levels of SeP mRNA. The response of the SeP promoter to 3-MC was abrogated by point mutations introduced at the two identified FoxO binding elements of the SeP promoter, implying that interaction of FoxO proteins with these sites is essential for the downregulation of promoter activity. In addition to FoxO activity being modulated by xenobiotics, it was then demonstrated that FoxO expression was also modulated by exposure of cells to PAH or FICZ. FoxO4 mRNA levels were downregulated in hepatoma cells exposed to 3-MC or FICZ. Similarly, insulin treatment caused a downregulation of mRNA levels of FoxO 1a, 3a and 4 in hepatoma cells. (orig.)

  13. Metabolism of UV-filter benzophenone-3 by rat and human liver microsomes and its effect on endocrine-disrupting activity

    Benzophenone-3 (2-hydroxy-4-methoxybenzophenone; BP-3) is widely used as sunscreen for protection of human skin and hair from damage by ultraviolet (UV) radiation. In this study, we examined the metabolism of BP-3 by rat and human liver microsomes, and the estrogenic and anti-androgenic activities of the metabolites. When BP-3 was incubated with rat liver microsomes in the presence of NADPH, 2,4,5-trihydroxybenzophenone (2,4,5-triOH BP) and 3-hydroxylated BP-3 (3-OH BP-3) were newly identified as metabolites, together with previously detected metabolites 5-hydroxylated BP-3 (5-OH BP-3), a 4-desmethylated metabolite (2,4-diOH BP) and 2,3,4-trihydroxybenzophenone (2,3,4-triOH BP). In studies with recombinant rat cytochrome P450, 3-OH BP-3 and 2,4,5-triOH BP were mainly formed by CYP1A1. BP-3 was also metabolized by human liver microsomes and CYP isoforms. In estrogen reporter (ER) assays using estrogen-responsive CHO cells, 2,4-diOH BP exhibited stronger estrogenic activity, 2,3,4-triOH BP exhibited similar activity, and 5-OH BP-3, 2,4,5-triOH BP and 3-OH BP-3 showed lower activity as compared to BP-3. Structural requirements for activity were investigated in a series of 14 BP-3 derivatives. When BP-3 was incubated with liver microsomes from untreated rats or phenobarbital-, 3-methylcholanthrene-, or acetone-treated rats in the presence of NADPH, estrogenic activity was increased. However, liver microsomes from dexamethasone-treated rats showed decreased estrogenic activity due to formation of inactive 5-OH BP-3 and reduced formation of active 2,4-diOH BP. Anti-androgenic activity of BP-3 was decreased after incubation with liver microsomes. - Highlights: • Metabolic modification of the endocrine-disrupting activity of BP-3 was examined. • 2,4,5-TriOH BP and 3-OH BP-3 were identified as new BP-3 metabolites. • 2,4-DiOH BP and 2,3,4-triOH BP exhibited high or similar estrogenic activities. • Estrogenic activity of BP-3 was enhanced by incubation with rat liver

  14. Differential effects of mercury, lead and copper on the constitutive and inducible expression of aryl hydrocarbon receptor (AHR)-regulated genes in cultured hepatoma Hepa 1c1c7 cells.

    Korashy, Hesham M; El-Kadi, Ayman O S

    2004-09-01

    Both simultaneous and sequential exposure to heavy metals and aryl hydrocarbon receptor (AHR)-ligands potentially occur in human populations, yet there have been relatively few studies of combined effects of heavy metals and AHR-ligands on AHR-regulated genes. To investigate the effects of heavy metals on AHR-regulated genes; cytochrome P450 1a1 (cyp1a1), NAD(P)H:quinone oxidoreductase (QOR) and glutathione S-transferase Ya (GST Ya), murine hepatoma Hepa 1c1c7 cells were incubated with increasing concentrations of Hg2+ (2.5-10 microM), Pb2+ (10-100 microM), and Cu2+ (1-100 microM) alone or with the AHR-ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (0.1 nM), 3-methylcholanthrene (0.25 microM), beta-naphthoflavone (10 microM), or benzo[a]pyrene (1 microM). The results clearly showed that metals alone did not significantly alter the cyp1a1 activity and protein levels but increased its mRNA expression, whereas a significant reduction in AHR ligand-mediated induction of cyp1a1 activity was observed by all metals. The decrease in cyp1a1 activity was associated with an increase, no change, or decrease in cyp1a1 mRNA and protein levels by Hg2+, Pb2+ and Cu2+ respectively, suggesting pre- and post-transcription mechanisms are involved. With respect to QOR, the activity and mRNA levels were increased by all metals in the absence or presence of an AHR-ligand, with the exception of Cu2+ which significantly decreased the induction of QOR. Differently, GST Ya activity was significantly increased by Cu2+ and Pb2+ and inhibited by Hg2+, while its mRNA was increased by Hg2+ and Pb2+ and decreased by Cu2+. All metals significantly increased the expression of heme oxygenase-1, which coincided with the changes in the phase I and phase II enzyme activities. These results demonstrate that heavy metals differentially modulate the constitutive and the inducible expression of AHR-regulated genes. PMID:15297030

  15. The molecular etiology and prevention of estrogen-initiated cancers: Ockham's Razor: Pluralitas non est ponenda sine necessitate. Plurality should not be posited without necessity.

    Cavalieri, Ercole; Rogan, Eleanor

    2014-04-01

    Elucidation of estrogen carcinogenesis required a few fundamental discoveries made by studying the mechanism of carcinogenesis of polycyclic aromatic hydrocarbons (PAH). The two major mechanisms of metabolic activation of PAH involve formation of radical cations and diol epoxides as ultimate carcinogenic metabolites. These intermediates react with DNA to yield two types of adducts: stable adducts that remain in DNA unless removed by repair and depurinating adducts that are lost from DNA by cleavage of the glycosyl bond between the purine base and deoxyribose. The potent carcinogenic PAH benzo[a]pyrene, dibenzo[a,l]pyrene, 7,12-dimethylbenz[a]anthracene and 3-methylcholanthrene predominantly form depurinating DNA adducts, leaving apurinic sites in the DNA that generate cancer-initiating mutations. This was discovered by correlation between the depurinating adducts formed in mouse skin by treatment with benzo[a]pyrene, dibenzo[a,l]pyrene or 7,12-dimethylbenz[a]anthracene and the site of mutations in the Harvey-ras oncogene in mouse skin papillomas initiated by one of these PAH. By applying some of these fundamental discoveries in PAH studies to estrogen carcinogenesis, the natural estrogens estrone (E1) and estradiol (E2) were found to be mutagenic and carcinogenic through formation of the depurinating estrogen-DNA adducts 4-OHE1(E2)-1-N3Ade and 4-OHE1(E2)-1-N7Gua. These adducts are generated by reaction of catechol estrogen quinones with DNA, analogously to the DNA adducts obtained from the catechol quinones of benzene, naphthalene, and the synthetic estrogens diethylstilbestrol and hexestrol. This is a weak mechanism of cancer initiation. Normally, estrogen metabolism is balanced and few estrogen-DNA adducts are formed. When estrogen metabolism becomes unbalanced, more catechol estrogen quinones are generated, resulting in higher levels of estrogen-DNA adducts, which can be used as biomarkers of unbalanced estrogen metabolism and, thus, cancer risk. The ratio of