sodium-nitrite and Carcinoma--Hepatocellular

Recent studies have demonstrated that nitrite and ammonia levels are higher in the tumor environment, but their effects on cancer cells remains unclear. The present study was designed to determine the effects of nitrite and ammonia on tumor invasion and the role of reactive oxygen (ROS)/ornithine decarboxylase (ODC) pathway. SMMC-7721 cells were treated with sodium nitrite, ammonium chloride, sodium nitrite and ammonium chloride mixture for 24 h, the cell viability was analyzed using the MTT assay, cell invasion was analyzed with the transwell assay, the intracellular ROS levels were detected with a reactive oxygen species (ROS) test kits, the expression of intracellular ODC was examined with immunofluorescence and Western blot, the expression of matrix metallopeptidase-2 (MMP-2) and MMP-9 were analyzed by Western blot. Compared with the control group, SMMC-7721 cells exhibited an increase in cell viability, invasion ability, ROS levels and ODC protein after exposure to 150 μmol·L(-1) sodium nitrite and ammonium chloride mixture for 24 h. The invasive activity was reduced by ROS scavenger N-acetycysteine (NAC) in SMMC-7721 cells. The specific ODC inhibitor difluoromethylornithine (DFMO) increased ROS levels and weakened the ability of sodium nitrite and ammonium chloride mixture in the regulation of invasion of SMMC-7721 cells. These data demonstrated that sodium nitrite and ammonium chloride mixture promote invasion of SMMC-7721 cells by enhancing ROS/ODC pathway.

Topics: Ammonia; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Survival; Humans; Liver Neoplasms; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Neoplasm Invasiveness; Ornithine Decarboxylase; Reactive Oxygen Species; Sodium Nitrite

Nitrites play multiple characteristic functions in invasion and metastasis of hepatic cancer cells, but the exact mechanism is not yet known. Cancer cells can maintain the malignant characteristics via clearance of excess mitochondria by mitophagy. The purpose of this article was to determine the roles of nitrite, reactive oxygen species (ROS) and hypoxia inducing factor 1 alpha (HIF-1 α) in mitophagy of hepatic cancer cells. After exposure of human hepatocellular carcinoma SMMC-7721 cells to a serial concentrations of sodium nitrite for 24 h under normal oxygen, the maximal cell vitality was increased by 16 mg x (-1) sodium nitrite. In addition, the potentials of migration and invasion for SMMC-7721 cells were increased significantly at the same time. Furthermore, sodium nitrite exposure displayed an increase of stress fibers, lamellipodum and perinuclear mitochondrial distribution by cell staining with Actin-Tracker Green and Mito-Tracker Red, which was reversed by N-acetylcysteine (NAC, a reactive oxygen scavenger). DCFH-DA staining with fluorescent microscopy showed that the intracellular level of ROS concentration was increased by the sodium nitrite treatment. LC3 immunostaining and Western blot results showed that sodium nitrite enhanced cell autophagy flux. Under the transmission electron microscopy (TEM), more autolysosomes formed after sodium nitrite treatment and NAC could prevent autophagosome degradation. RT-PCR results indicated that the expression levels of COX I and COXIV mRNA were decreased significantly after sodium nitrite treatment. Meanwhile, laser scanning confocal microscopy showed that sodium nitrite significantly reduced mitochondrial mass detected by Mito-Tracker Green staining. The expression levels of HIF-1α, Beclin-1 and Bnip3 (mitophagy marker molecular) increased remarkably after sodium nitrite treatment, which were reversed by NAC. Our results demonstrated that sodium nitrite (16 mg x L(-1)) increased the potentials of invasion and migration of hepatic cancer SMMC-7721 cells through induction of ROS and HIF-1α mediated mitophagy.

Topics: Acetylcysteine; Autophagy; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Movement; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Liver Neoplasms; Mitophagy; Neoplasm Invasiveness; Nitrites; Reactive Oxygen Species; Sodium Nitrite

This study is to report the determination of the effect of sodium nitrite induced oxygen species (ROS) on the epithelial-mesenchymal transition in hepatoma cells in mice bearing H22 and investigation of its role in hypoxia-inducible factor 1alpha (HIF-1alpha) in this process. Mice hepatocarcinoma cell line H22 was inoculated subcutaneously into right axillary of sixty male Kunming mice and then randomly divided into four groups: control group; low-dose sodium nitrite group (10 mg x kg(-1)), medium-dose sodium nitrite group (20 mg x kg(-1)) and high-dose sodium nitrite group (30 mg x kg(-1)). Sodium nitrite group was given (ig) sodium nitrite with 10-30 mg x kg(-1) x d(-1) for 21 days. Compared with control group, there was no obvious difference between the two groups in the volume or weight of xenografts, but in sodium nitrite treatment group, the activity of SOD and CAT decreased and contents of MDA or nitrite increased in tumor tissue of mice bearing H22; epithelial-mesenchymal transition (EMT) of hepatoma cells was induced, the EMT-phenotype tumors displayed a greater degree of local aggressiveness, with dissection through adjacent fascia and skeletal muscle. The increased expression of HIF-la and vimentin and declination of E-cadherin were confirmed by immunohistochemistry and Western blotting. These data indicate sodium nitrite treatment could improve the epithelial-mesenchymal transition of xenografts in mice bearing H22, which might relate to the fact that ROS mediated signal pathway increased the expression of HIF-1alpha.

Topics: Animals; Cadherins; Carcinoma, Hepatocellular; Catalase; Cell Line, Tumor; Dose-Response Relationship, Drug; Epithelial-Mesenchymal Transition; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Liver Neoplasms; Male; Malondialdehyde; Mice; Neoplasm Transplantation; Random Allocation; Reactive Oxygen Species; Signal Transduction; Sodium Nitrite; Superoxide Dismutase; Tumor Burden; Vimentin

This study is to find out the induction by sodium nitrite of epithelial-mesenchymal transition (EMT) in human hepatocellular carcinoma cells, SMMC-7721. After treatment of SMMC-7721 with 0.25 - 25 mmol.L-1 sodium nitrite for 48 h, the assays used include enzyme-linked immunosorbent assay (ELISA) for evaluation of TGF-beta1, IL-6 and IL-8 level in the conditioned medium, phase-contrast microscopy for morphology observation, and scratch wound healing as well as transwell migration assays for measurement of migration and metastatic potential. Additionally, the hallmarks of EMT, p-AKT and its downstream signaling molecules were examined by Western blotting. The results showed that TGF-beta1 secreted by SMMC-7721 elevated significantly in a dose-dependent fashion, whereas the increased IL-8 and IL-6 did not show dose-dependent response. The EMT was induced by exposure of SMMC-7721 with 0.25 mmol.L-1 of sodium nitrite, which was characterized by increased level of Vimentin, decreased E-cadherin and elevated activity of migration and metastatic potential. The results suggest that sodium nitrite could induce SMMC-7721 EMT by increased secretion of TGF-beta1 and IL-8.

Topics: Cadherins; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Movement; Dose-Response Relationship, Drug; Epithelial-Mesenchymal Transition; Humans; Interleukin-6; Interleukin-8; Liver Neoplasms; Neoplasm Invasiveness; NF-kappa B; Proto-Oncogene Proteins c-akt; Sodium Nitrite; Transforming Growth Factor beta1; Twist-Related Protein 1; Vimentin

This study is to investigate the cytoprotective role of NaNO2 preconditioning against ethanol induced damage in human hepatoma SMMC-7721 cells. The cells were preconditioned with NaNO2 (0.25 mmol x L(-1)) for 24 hours or 4 weeks, and then exposed to ethanol (200 mmol x L(-1)) for additional 12 h and untreated cells served as control. Both temporal and chronic NaNO2 preconditioning could prevent ethanol elicited cytotoxicity as evidenced by thiazolyl blue (MTT). NaNO2 preconditioning also could inhibit ethanol-induced apoptosis, which was confirmed by FITC-Annexin V/PI flow cytometer and Hoechst 33258 and PI staining. Further, simultaneous NaNO2 preconditioning treatment along with ethanol showed protection against ethanol mediated cellular damage as indicated by significantly decreased levels of malondialdehyde (MDA) and elevated activities of superoxide dismutase (SOD) and catalase (CAT). Western blotting analysis revealed that in ethanol treated cells preconditioned with NaNO2, the HIF-1alpha and Bcl-2 increased obviously, while the expression of pro-apoptotic proteins, including Bax, Caspase-9, Caspase-3 decreased. The results showed that low doses of NaNO2 preconditioning resistant to ethanol-induced human hepatoma SMMC-7721 cells apoptosis, which mechanism may be related to increased expression of HIF-1alpha in the cells.

Topics: Apoptosis; bcl-2-Associated X Protein; Carcinoma, Hepatocellular; Caspase 3; Caspase 9; Catalase; Cell Line, Tumor; Cell Proliferation; Ethanol; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Liver Neoplasms; Malondialdehyde; Proto-Oncogene Proteins c-bcl-2; Sodium Nitrite; Superoxide Dismutase

2-acetyl aminofluorene (AAF) reacts in acidic conditions with nitrous fume yielding N-nitroso-AAF (N-NO-AAF), as previously described, that exerts more toxic and mutagenic effects than its parental compound. In this study, the effect of sodium nitrite (NaNO2) on the tumorigenicity of AAF in rats fed with AAF and NaNO2 was observed. Wistar rats were divided into five groups: group I served as control; group II were treated with NaNO2 (0.3%); group III was given 0.02% AAF alone; groups IV and V received both AAF and NaNO2 (0.2 and 0.3% respectively) in their diet for 12 weeks. At the end of the experiment, all rats in groups III, IV and V developed early stage phenomena of hepatocellular carcinoma, including hepatomegaly with variable-sized foci and neoplastic nodules. Severe damage was observed in the rats treated with AAF and NaNO2. Feeding of AAF (0.02%) for 3 months elevated the levels of c-Fos, c-Jun and c-Myc proteins in the rat livers. The AAF-induced c-Jun, c-Fos and c-Myc expressions were significantly magnified (P < 0.001) by NaNO2. These data confirmed that the strengthening of AAF-induced hepatocarcinogenesis by NaNO2 should be associated with its enhancing effect on the AAF-induced increases in the expressions of c-Jun, c-Fos and c-Myc.

Topics: 2-Acetylaminofluorene; Administration, Oral; Animals; Carcinogens; Carcinoma, Hepatocellular; Drug Interactions; Food Preservatives; Immunohistochemistry; Liver; Liver Neoplasms; Male; Organ Size; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-fos; Proto-Oncogene Proteins c-jun; Proto-Oncogene Proteins c-myc; Rats; Rats, Wistar; Sodium Nitrite