The eleven Chinese herbal medicine containing flavonoids are applied as raw materials to explore the relationship between the inhibitory ratio of nitrosamine synthesis, the scavenging ratio of nitrite and the flavonoid content in the samples. The inhibitory ratio of nitrosamine synthesis and the scavenging ratio of nitrite of the 11 herbal medicines, Vit C and rutin were determined in intro compare with Vit C and the standard ample of rutin. The results indicate that each sample exhibits certain ability to inhibitiory nitrosamine synthesis. Among these samples, Honeysuckle flower is found to be of best effects, its inhibitory ratio and scavenging ratio reaches 78.5% and 60.5%, respectively. Except kudzuvine root, the other samples with higher content of flavonoid result in a higher inhibitory or scavenging ratio, and the relative coefficient reaches a value of 0.9338 and 0.9272, respectively, displaying notable positive correlation. The concentrations of IC50 (g x L(-1)) of flavonoid extracted from honeysuckle, rutin and VC were 0.013, 0.022 and 0.187, respectively. While the inhibitory ratio of synthesis of nitrosamines reached 50%, and those were 0.042, 0.024 and 0.041, respectively. While scavenging ratio of nitrite reaches 50%. The inhibitory ratio of synthesis of nitrosamine of flavonoids extracted from honeysuckle flower is higher than that of Vit C and rutin, and the scavenging ratio of nitrite is similar to that of Vit C.
Drug Interactions ; Drugs, Chinese Herbal ; analysis ; pharmacology ; Flavonoids ; analysis ; pharmacology ; Nitrosamines ; chemical synthesis ; pharmacology ; Plants, Medicinal ; chemistry

The effect of four alkylating agents (MMS, EMs, DMN, DEM), under various con centrations on mouse bone marrow erythrocytes, were studied by means of the micronucleus test. The results obtained were as follows: 1) The lethal doses on mice were MMS = 130 mg/kg/bw, EMS = 300 mg/kg/bw, DMN = 50 mg/kg/bw and DEN = 70 mg/kg/bw. 2) Micronuclei were easily seen and in different controls the micronulei were found a little over 0.1%. 3) The dose-effect relationship was obtained. In the MMS and EMS treated groups, incidences of micronulei were 0.45 to 2.56% and 0.4 to 2.1% respectively. 4) In the DMN and DEN treated groups, incidences varied between 0.15 to 0.90 % and 0.2 to 1.02% respectively. 5) Four alkylating agents were compared and discussed with respect to micro nucleus production from chromosomal aberrations.
Animal ; Bone Marrow/ultrastructure ; Carcinogens/pharmacology* ; Cell Nucleus/drug effects* ; Chromosome Aberrations* ; Erythrocytes/ultrastructure ; Female ; Mesylates/pharmacology* ; Mice ; Mutagens/pharmacology ; Nitrosamines/pharmacology*

The ultrastructural alterations in rat liver by feeding NHM(nitrosohexamethylenemine). These are described at intervals of 10 days, 5 weeks, 11 weeks, 14 weeks, 19 weeks, and 22 weeks. The group at 5 and 11 weeks showed hyperplastic lesions but, no nuclear change. There were dilated rough endoplasmic reticulum with detached ribosomes, and alteration of mitochondria. The mitochondria showed a dense matrix which often included membranous materials. In the l4, 19, and 22 week groups, it showed nodular lesion which had atypical cells, and it was observed that the nucleus were enlarged and nucleoli were segregated. The bile canaliculi were dilated and contained dense materials.
Animal ; Female ; Liver/drug effects* ; Liver/pathology ; Methenamine/pharmacology* ; Microscopy, Electron ; Mitochondria, Liver/drug effects ; Nitrosamines/pharmacology ; Nitroso Compounds/pharmacology* ; Rats

OBJECTIVETo establish an in vitro heterogeneous expression model of human CYP2E1 (hCYP2E1) cDNA and investigate the effect of the chemical carcinogenic N, N'-dinitrosopiperazine (DNP) on the expression of CYP2E1.

METHODSExogenous hCYP2E1 was introduced into the mouse derived NIH3T3 cells using the lipofectamine transfection technique. Integration of exogenous hCYP2E1 gene was identified by PCR and Southern blot. After treatment with various concentration of ethanol and DNP on the transfected NIH3T3 cell cultures, RT-PCR and Western blot was applied to detect the expression level of CYP2E1.

RESULTSTwo cell clones with integration and stable expression of exogenous hCYP2E1 were obtained and designated as NIH3T3-2E1-A4 and NIH3T3-2E1-A8 respectively. The expression of both hCYP2E1 mRNA and protein products was promoted after either ethanol or DNP treatment.

CONCLUSIONThe results suggested that the promoted expression of hCYP2E1 induced by DNP and /or ethanol is due to enhanced transcription. The mechanism of DNP carcinogenes is might be related to this in situ activated metabolism by CYP2E1.

3T3 Cells ; Animals ; Carcinogens ; toxicity ; Cytochrome P-450 CYP2E1 ; genetics ; Ethanol ; pharmacology ; Gene Expression Regulation, Enzymologic ; drug effects ; Humans ; Mice ; Nitrosamines ; toxicity ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

This study was performed to determine the ability of eliminating sodium nitrite and blocking nitrosamine synthesis by anthocyanin from the skin of Alpinia galanga. purified by macroporous resin. The test was conducted under the condition of the simulated human gastric juice (pH 3.0, 37 degrees C) with VitC as positive control. The results showed that the max capability of eliminating sodium nitrite was 87.14%, which is 1.6 times sronger than that of VitC, and the max capability of blocking nitrosamine synthesis was 97.82%, which is 8 times sronger than that of VitC.
Alpinia ; chemistry ; Anthocyanins ; isolation & purification ; pharmacology ; Antioxidants ; pharmacology ; Ascorbic Acid ; pharmacology ; Gastric Juice ; chemistry ; Humans ; Hydrogen-Ion Concentration ; Hydrolysis ; drug effects ; Nitrosamines ; antagonists & inhibitors ; metabolism ; Plant Epidermis ; chemistry ; Sodium Nitrite ; metabolism

The modifying potential of capsaicin (CAP) on lesion development was examined in a rat multiorgan carcinogenesis model. Groups 1 and 2 were treated sequentially with diethylnitrosamine (DEN) (100 mg/kg, ip, single dose at commencement), N-methylnitrosourea (MNU) (20 mg/kg, ip, 4 doses at days 2, 5, 8, and 11), and N,N-dibutylnitrosamine (DBN) (0.05% in drinking water during weeks 3 and 4). Group 3 received vehicles without carcinogens during the initiation period. Group 4 served as the untreated control. After this initiating procedure, Groups 2 and 3 were administered a diet containing 0.01% CAP. All surviving animals were killed 20 weeks after the beginning of the experiment and the target organs examined histopathologically. The induction of GST-P+ hepatic foci in rats treated with carcinogens was significantly inhibited by treatment with CAP. CAP treatment significantly decreased the incidence of adenoma of the lung but increased the incidence of papillary or nodular (PN) hyperplasia of the urinary bladder. The tumor incidence of other organs, such as the kidney and thyroid, was not significantly different from the corresponding controls. These results demonstrated that concurrent treatment with CAP not only can inhibit carcinogenesis but can also enhance it depending on the organ. Thus, this wide-spectrum initiation model could be used to confirm organ-specific modification potential and, in addition, demonstrate different modifying effects of CAP on liver, lung, and bladder carcinogenesis.
Animals ; Capsaicin/pharmacology/*toxicity ; Cocarcinogenesis ; Diethylnitrosamine ; Liver Neoplasms, Experimental/chemically induced/prevention & control ; Lung Neoplasms/chemically induced/prevention & control ; Male ; Methylnitrosourea ; Neoplasms, Experimental/*chemically induced/prevention & control ; Nitrosamines ; Rats ; Rats, Inbred F344 ; Urinary Bladder Neoplasms/chemically induced

OBJECTIVETo study the alteration of circulating microRNAs in 4-(methylnitrosamino)-1-(3-pyridyl) -1-butanone (NNK)-induced early stage lung carcinogenesis.

METHODSA lung cancer model of male F344 rats was induced with systemic NNK and levels of 8 lung cancer-associated miRNAs in whole blood and serum of rats were measured by quantitative RT-PCR of each at weeks 1, 5, 10, and 20 following NNK treatment.

RESULTSNo lung cancer was detected in control group and NNK treatment group at week 20 following NNK treatment. The levels of some circulating miRNAs were significantly higher in NNK treatment group than in control group. The miR-210 was down-regulated and the miR-206 was up-regulated in NNK treatment group. The expression level of circulating miRNAs changed from week 1 to week 20 following NNK treatment.

CONCLUSIONThe expression level of circulating miRNAs is related to NNK-induced early stage lung carcinogenesis in rats and can therefore serve as its potential indicator.

Adenocarcinoma ; chemically induced ; Animals ; Carcinogenesis ; Cell Line, Tumor ; Gene Expression Regulation ; physiology ; Humans ; Lung ; drug effects ; pathology ; Lung Neoplasms ; blood ; chemically induced ; metabolism ; Male ; MicroRNAs ; blood ; genetics ; metabolism ; Nitrosamines ; pharmacology ; Rats ; Rats, Inbred F344

Evidences show that eukaryotic mRNAs can perform protein translation through internal ribosome entry sites (IRES). 5'-Untranslated region of the mRNA encoding apoptotic protease-activating factor 1 (Apaf-1) contains IRES, and, thus, can be translated in a cap-independent manner. Effects of changes in protein translation pattern through rapamycin pretreatment on 4-(methylnitrosamino)-1-(3-pyridyl)-butanone(NNK, tobacco-specific lung carcinogen)-induced apoptosis in human bronchial epithelial cells were examined by caspase assay, FACS analysis, Western blotting, and transient transfection. Results showed that NNK induced apoptosis in concentration- and time-dependent manners. NNK-induced apoptosis occurred initially through cap-independent protein translation, which during later stage was replaced by cap-dependent protein translation. Our data may be pplicable as the mechanical basis of lung cancer treatment.
Antibiotics, Antineoplastic/pharmacology ; Apoptosis/*drug effects ; Apoptotic Protease-Activating Factor 1 ; BH3 Interacting Domain Death Agonist Protein ; Blotting, Western ; Bronchi/metabolism/*pathology ; Carcinogens/*pharmacology ; Carrier Proteins/metabolism ; Caspases/metabolism ; Cytochromes c/metabolism ; Dose-Response Relationship, Drug ; Epithelial Cells/metabolism/*pathology ; Eukaryotic Initiation Factor-4E/metabolism ; Flow Cytometry ; Humans ; Nitrosamines/*pharmacology ; Protein Biosynthesis ; Proteins/metabolism ; Proto-Oncogene Proteins c-bcl-2/metabolism ; RNA Cap-Binding Proteins/*physiology ; Sirolimus/pharmacology ; Time Factors ; bcl-2-Associated X Protein

OBJECTIVETo investigate the enhancive effect of N,N'-dinitrosopiperazine (DNP) on induced carcinogenesis in nasal and/or nasopharyngeal epithelia among TgN(p53mt-LMP1)/HT transgenic mice to examine the underlying mechanism for the development of nasopharyngeal carcinoma (NPC).

METHODSTgN(p53mt-LMP1)/HT transgenic mice and the same strain of C(57)BL/6J wild-type mice both at the age of 5 months were randomly divided into 2 groups in parallel, respectively, i.e., TgN(p53mt-LMP1)/HT cancerous lesion-inducing group (TI), TgN(p53mt-LMP1)/HT control group (TC), C57BL/6J cancerous lesion-inducing group (CI), and C57BL/6J control group (CC). TI and CI mice were treated only with DNP for 16 weeks, twice each week, while TC and CC mice were given the same volume of saline as controls. At the end of treatment, animals were sacrificed to collect epithelial tissue samples from nasal cavity and nasopharynx for pathohistological evaluation by haematoxylin and eosin (HE) staining and for determination on the expression of TRAF2, c-Jun, and p16 by immunohistochemistry.

RESULTSAtypical hyperplasia was more significant in the samples of TI than in those of TC, CI, and CC, with the rates of lesions being 90%, 10%, 0, and 0 (P<0.01) respectively, though DNP was used alone in a much shortened inducing period at less dosage and without the use of carcinogenic promoter 12-O-tetradecanoylphorbol-13-acetate as usual. The expressions of tumor necrosis factor (TNF) receptor-associated factor 2 (TRAF2) and c-Jun in these samples were significantly up-regulated in TI (P<0.01), while the expression of p16 was significantly lower in TI than in the other groups (P<0.01).

CONCLUSIONTgN(p53mt-LMP1)/HT mice hold inherited constitutional defect in immune surveillance function, which can be aggravated by environmental carcinogens, such as DNP used even though in a much less strength. The enhanced carcinogenesis-inducing effect of DNP on TgN(p53mt-LMP1)/HT mice should be closely associated with abnormal signaling of activator protein-1 (AP-1) pathway, especially up-regulated expressions of TRAF2 and c-Jun, and down-regulated expression of p16.

Animals ; Epithelial Cells ; drug effects ; metabolism ; pathology ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Mice ; Mice, Transgenic ; Mutation ; genetics ; Nasopharyngeal Neoplasms ; chemically induced ; genetics ; metabolism ; pathology ; Nitrosamines ; pharmacology ; Nose Neoplasms ; chemically induced ; genetics ; metabolism ; pathology ; Precancerous Conditions ; chemically induced ; genetics ; pathology ; TNF Receptor-Associated Factor 2 ; metabolism ; Tumor Suppressor Protein p53 ; genetics ; metabolism ; Viral Matrix Proteins ; genetics ; metabolism