methylnitronitrosoguanidine and Carcinoma--Hepatocellular

Hepatocellular carcinoma is a malignancy with poor clinical prognosis. Hepatic oval cells (HOCs) tend to differentiate into cancerous hepatocellular carcinoma cells (HCCs) in the tumor microenvironment. The purpose of the present study was to explore the role of kangxianruangan granule (KXRG)‑containing serum in inhibiting the differentiation of HOCs into HCCs via the Wnt‑1/β‑catenin signaling pathway. N‑methyl‑N'‑nitro‑N‑nitrosoguanidine (MNNG) was applied to induce the transformation of the rat HOC cell line WB‑F344 into HCCs. The overexpression plasmid, Wnt‑1‑up, was utilized to increase Wnt‑1 expression. Subsequently, high, medium and low concentrations of KXRG were applied to MNNG‑treated WB‑F344 cells to assess the inhibitory effect of KXRG on cell differentiation. Flow cytometry was conducted to detect the cell cycle distribution, apoptotic rate and expression of cytokeratin‑19 (CK‑19) protein in cells. An immunofluorescence double staining protocol was used to detect the expression of Wnt‑1 and β‑catenin. ELISAs were performed to detect α fetoprotein in the cell supernatants. Reverse transcription‑quantitative PCR and western blotting were conducted to detect the mRNA and protein expression levels of Wnt‑1, β‑catenin, Cyclin D1, C‑myc, matrix metalloproteinase‑7 (MMP‑7), Axin2 and epithelial cell adhesion molecule (EpCAM) in cells. Compared with the normal group, the apoptotic rate, proportion of S phase cells, concentration of AFP in the cell supernatant, level of CK‑19 protein, and mRNA and protein expression levels of Wnt‑1, β‑catenin, Cyclin D1, C‑myc, MMP‑7, Axin2 and EpCAM were all significantly increased in the model group. Addition of KXRG significantly reduced the aforementioned indicators compared with the model group. Moreover, Wnt‑1 overexpression further increased the aforementioned indicators compared with the model group, whereas KXRG significantly inhibited these effects. The results indicated that KXRG inhibited the differentiation of HOCs into HCCs via the Wnt‑1/β‑catenin signaling pathway, which suggested the potential clinical application of KXRG for the prevention of hepatocellular carcinoma.

Topics: Animals; Carcinoma, Hepatocellular; Cell Differentiation; Cell Line, Tumor; Cell Transformation, Neoplastic; Disease Models, Animal; Drugs, Chinese Herbal; Humans; Liver; Liver Neoplasms, Experimental; Male; Methylnitronitrosoguanidine; Rats; Tumor Microenvironment; Wnt Signaling Pathway

Bamboo salt is a traditional Korean baked solar salt processed by packing the solar salt in bamboo joint cases and heating it several times to high temperatures. The antimutagenic activity and in vitro anticancer effects of bamboo salt on HepG2 human hepatoma cells were investigated and compared to those of other salt samples. Although solar salt and purified salt exhibited comutagenicity with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in the Salmonella typhimurium TA100 strain, bamboo salt was associated with a lower degree of comutagenicity or antimutagenic activity. Bamboo salt baked nine times (9×) showed a greater increase in antimutagenic activity than salts baked once (1×) or three times (3×). At a concentration of 1%, the growth rate of HepG2 cells treated with 9× bamboo salt determined by a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MIT) assay was reduced by 65%; this rate of inhibition was higher than that achieved with 1× baked bamboo salt (40%). Purified and solar salts had relatively lower inhibitory effects on growth rate (25% and 29%, respectively). Compared to the other salt samples, 9× bamboo salt significantly (p<0.05) induced apoptosis as determined by 4,6-diamidino-2-phenylindole (DAPI) staining and flow cytometry analysis. It also upregulated the expression of Bax, caspase-9 and caspase-3; and downregulated Bcl-2 expression. The bamboo salts, especially 9× bamboo salt, also significantly (p<0.05) downregulated the expression of inflammation-related NF-κB, iNOS, and COX-2, and upregulated the gene expression of IκB-α compared to the other salt sample.

Topics: Antimutagenic Agents; Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Carcinoma, Hepatocellular; Caspases; Cell Line, Tumor; Cyclooxygenase 2; Dose-Response Relationship, Drug; Hep G2 Cells; Humans; In Vitro Techniques; Liver Neoplasms; Methylnitronitrosoguanidine; NF-kappa B; Nitric Oxide Synthase Type II; Plant Extracts; Proto-Oncogene Proteins c-bcl-2; Salts; Sasa

The involvement of DNA damage in heat shock-induced cell death remains controversial. To investigate whether heat shock can induce DNA damage, we tested the induction of gammaH2AX foci formation, a sensitive indicator for DNA double strand breaks (DSBs), by heat shock treatment in several cell lines including HeLa, CHL, HepG2, and 293 cells, as well as human spermatozoa. Although heat shock treatment can decrease cell viability, no induction of gammaH2AX foci formation was observed in any of these cells. In addition, a p53-deficient cell line (U2OSE6tet24) and a flap endonuclease 1 (FEN1)-deficient cell line (FL-FEN1(-)) also did not show induction of gammaH2AX foci after heat shock treatment. Finally, it was found that 30min of pre-heat shock can inhibit gammaH2AX foci formation induced by an alkylating agent, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which is known to induce gammaH2AX foci formation. On the other hand, heat shock after MNNG treatment did not affect the gammaH2AX foci formation induced by MNNG. Taken together, these data suggest that although heat shock might influence the gammaH2AX foci formation process, it does not induce DNA damage in the cells tested in this study.

Topics: Carcinogens; Carcinoma, Hepatocellular; Cell Line; Cell Line, Tumor; Cell Survival; DNA; DNA Damage; DNA, Neoplasm; Flow Cytometry; Fluorescein-5-isothiocyanate; Fluorescent Antibody Technique, Direct; Fluorescent Dyes; HeLa Cells; Histones; Hot Temperature; Humans; Indoles; Liver Neoplasms; Male; Methylnitronitrosoguanidine; Microscopy, Fluorescence; Spermatozoa

The aim of the present investigation was to evaluate abnormal changes in trace element concentrations during carcinogenesis. First, Al, Zn and Cu in the liver tissues of rats were measured by atomic absorption analysis over a half year of hepatocarcinogenesis. Male Wistar rats were given carcinogenic food containing 600 mg/kg of 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB) in a basal diet for several months. After 4 to 6 months of feeding, hepatocarcinomas developed in the rats. Zn and Cu concentrations in the hepatocarcinomas of the 3'-MeDAB group significantly decreased as compared with normal liver tissues of the control groups. On the other hand, the aluminum concentration in the hepatocarcinomas was more than three times that in the normal liver tissues. The Al and Se contents of developed gastric and mammary cancers were measured in Experiment II. Male and female rats were given 1-methyl-3-nitrothoguanidine(MNNG) and 2,7-dimehtylbenz(a)anthracene(DMBA), respectively. After several months, carcinomas developed in over half of the rats. The Al and Se concentrations in cancers, livers and the blood were determined by atomic absorption analysis. It was shown that both gastric and mammary carcinomas contained a high level of aluminum and very little selenium in comparison with normal liver tissues. The present study demonstrated that aluminum accumulated in experimentally induced carcinomas in rats, i.e., cancers of the liver, stomach, duodenum and mammary glands.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Aluminum; Animals; Carcinoma, Hepatocellular; Copper; Disease Models, Animal; Duodenal Neoplasms; Female; Liver Neoplasms; Male; Mammary Neoplasms, Experimental; Methyldimethylaminoazobenzene; Methylnitronitrosoguanidine; Rats; Rats, Sprague-Dawley; Rats, Wistar; Reference Standards; Spectrophotometry, Atomic; Stomach Neoplasms; Zinc

The involvement of O6-methylguanine (O6-meGua) in mutagenesis is well established, while the toxic effect of these residues is still controversial. In this study, we compare the cytotoxicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and N-methyl-N-nitrosourea (MNU) on three cell lines of different origin, which have different abilities to repair O6-meGua residues (Mer phenotype): a human hepatoma cell line (LICH cells, Mer+), a rat hepatoma cell line (H4 cells, Mer+) and a Chinese hamster cell line (CHO cells, Mer- phenotype). LICH and CHO cells show the same sensitivity to the killing effect of MNNG and MNU and are approximately 5-fold more sensitive than H4 cells. However, LICH and H4 cells share similar sensitivities to the toxic effect of 1,3-bis(2-chloroethyl)-1-nitrosourea. O6-meGua residues are removed at the same rate from the DNA of [3H]MNU-treated LICH and H4 cells, which also do not differ in the rate of removal of N3-methyladenine residues nor in overall DNA repair synthesis. The results suggest that MNNG and MNU produce a lethal lesion that is repaired by a process that does not involve the alkyltransferase.

Topics: Alkylating Agents; Animals; Carcinoma, Hepatocellular; Cell Death; Cell Division; CHO Cells; Cricetinae; DNA Damage; DNA Repair; Drug Hypersensitivity; Drug Resistance; Guanine; Humans; Liver Neoplasms; Liver Neoplasms, Experimental; Methylnitronitrosoguanidine; Methylnitrosourea; Methyltransferases; O(6)-Methylguanine-DNA Methyltransferase; Phenotype; Rats; Tumor Cells, Cultured

Hepatoma tissue culture (HTC) cells were incubated in the presence of the alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) to study the variations in the bisnucleosides polyphosphates (Ap4X) pool size. A transient but sensitive accumulation of these compounds is observed; if 3-aminobenzamide (3AB) which is a potent inhibitor of the ADP-ribosyltransferase (ADPRT) is added after the MNNG treatment, a more pronounced and persistent accumulation of Ap4X can be seen. A moderate heat-shock (30 min at 43 degrees C) results also in a small accumulation of Ap4X but the shape of the accumulation curve is quite different and the increase of the Ap4X pool is not sensitive to the presence of 3AB. However, both MNNG treatment and hyperthermia cause a marked inhibition of protein synthesis. On the other hand, the ADPRT activity is enhanced in the presence of MNNG whereas hyperthermia has little or a slightly inhibitory effect on this activity. These results suggest that MNNG treatment triggers an Ap4X accumulation in eukaryotic cells different from that observed after heat-shock and it seems likely that these compounds are involved in the DNA excision repair system in which the ADPRT enzyme is also implicated.

Topics: Adenine Nucleotides; Alkylation; Benzamides; Carcinoma, Hepatocellular; Dinucleoside Phosphates; DNA; DNA Repair; Hot Temperature; Kinetics; Liver Neoplasms; Methylnitronitrosoguanidine; NAD; Poly Adenosine Diphosphate Ribose; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Protein Biosynthesis; Tumor Cells, Cultured

Polymethylene-bis(1-nitrosourea), polymethylene-bis(1-nitroso-3-nitroguanidine), and polymethylene-bis(1-nitroso-p-toluenesulfonamide) derivatives were tested for antitumor effect against rat ascites hepatoma AH-13 and mouse leukemia L-1210. Bisnitrosoureas were effective against AH-13 and L-1210, bisnitrosoguanidines were effective against AH-13 alone, and bisnitrosotoluene-sulfonamides were ineffective against both tumor lines. Of all these compounds, 1,1'-ethylene-bis(1-nitrosourea) (EBNU) was the most effective. The antitumor effect of EBNU was compared with that of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Intraperitoneal administration of EBNU according to the schedule, day 1, days 1 and 5, and days 1, 5, and 9 after intraperitoneal inoculation of L-1210 showed marked prolongation of host survival, although the effective doses used were a few times higher than those used in BCNU to obtain a similar effect. The minimum effective dose (MED) of EBNU on AH-13 cells was estimated as 1 mg/kg, which was 10 times less than that of BCNU, suggesting that EBNU was more effective than BCNU against AH-13.

Topics: Animals; Antineoplastic Agents; Carcinoma, Hepatocellular; Carmustine; Drug Evaluation, Preclinical; Leukemia L1210; Liver Neoplasms; Methylnitronitrosoguanidine; Mice; Mice, Inbred DBA; Neoplasms, Experimental; Nitrosoguanidines; Nitrosourea Compounds; Rats; Sulfonamides; Tosyl Compounds

Topics: Adenocarcinoma; Animals; Carcinoid Tumor; Carcinoma, Hepatocellular; Carcinoma, Squamous Cell; Duodenal Neoplasms; Female; Hyperplasia; Liver Neoplasms; Male; Methylnitronitrosoguanidine; Neoplasms, Experimental; Nitrosoguanidines; Papilloma; Rats; Rodent Diseases; Stomach Neoplasms