[Sodium nitrite induces PC12 cell differentiation].

To investigate the potential ability of the nitrite to induce neuronal differentiation of PC12 cells, cultured PC12 cells planted on matrigel in the presence or absence of sodium nitrite were employed as model, nerve growth factor (NGF) served as a positive control. After 48 h, sodium nitrite enhanced cell viability and vascular endothelial growth factor (VEGF) secretion. Same as the effect of NGF, sodium nitrite (1.4 mmol x L(-1)) treated cultures contained a greater proportion of cells bearing neurites and neurites were much longer than those found in negative control cultures (P < 0.05). Compared with the negative control, sodium nitrite (1.4 mmol x L(-1)) also upregulated the expression of VEGF mRNA (P < 0.05) and hypoxia inducible factor 1 alpha (HIF-1 alpha) or VEGF protein expression (P < 0.05) in cultures of PC12 cells. On the other hand, these effects of the sodium nitrite were likely mediated by HIF-1alpha, since their effects were antagonized by addition of HIF-1alpha inhibitor YC-1. Taken together, these results suggest that low doses of sodium nitrite could induce neurite outgrowth in PC12 cells by activating the HIF-1alpha-VEGF pathway.

Piperonal ciprofloxacin hydrazone induces growth arrest and apoptosis of human hepatocarcinoma SMMC-7721 cells.

AIM: To investigate the cytotoxic effects of piperonal ciprofloxacin hydrazone (QNT4), a novel antibacterial fluoroquinolone derivative, against human hepatocarcinoma SMMC-7721 cells. METHODS: Human hepatocarcinoma cells (SMMC-7721), human breast adenocarcinoma cells (MCF-7) and human colon adenocarcinoma cells (HCT-8) were tested. The effects of QNT4 on cell proliferation were examined using MTT assay. Cell apoptosis was determined using Hoechst 33258 fluorescence staining, TUNEL assay and agarose gel electrophoresis. The topoisomerase II activity was measured using agarose gel electrophoresis with the DNA plasmid pBR322 as the substrate. Mitochondrial membrane potential (Δψm) was measured using a high content screening imaging system. Protein expression of caspase-9, caspase-8, caspase-3, p53, Bcl-2, Bax, and cytochrome c was detected with Western blot analysis. RESULTS: Treatment with QNT4 (0.625-10 µmol/L) potently inhibited the proliferation of the cancer cells in time- and dose-dependent manners (the IC(50) value at 24 h in SMMC-7721 cells, MCF-7 cells and HCT-8 cells was 2.956±0.024, 3.710±0.027, and 3.694±0.030 µmol/L, respectively). Treatment of SMMC-7721 cells with QNT4 (0.2146, 2.964, and 4.600 µmol/L) for 24 h dose-dependently increased the percentage of apoptotic cells, elicited characteristic DNA "ladder" bands, and decreased the mitochondrial membrane potential. QNT4 dose-dependently increased topoisomerase II-mediated DNA breaks while inhibiting DNA relegation, thus keeping the DNA in fragments. Treatment of SMMC-7721 cells with QNT4 significantly increased cytochrome c in the cytosol, and decreased cytochrome c in the mitochondrial compartment. QNT4 (3-7.39 µmol/L) significantly increased the protein expression of p53, Bax, caspase-9, caspase-3, and the cleaved activated forms of caspase-9 and caspase-3 in SMMC-7721 cells. In contrast, the expression of Bcl-2 was decreased, while caspase-8 had no significant change. CONCLUSION: QNT4 induced the apoptosis of SMMC-7721 cells via inhibiting topoisomerase II activity and modulating mitochondrial-dependent pathways.

Sodium nitrite improves epithelial-mesenchymal transition of hepatoma cells in mice bearing H22 / 药学学报

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.

[Sodium nitrite induces epithelial-mesenchymal transition of SMMC-7721 cells].

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.

[Sodium nitrite preconditioning protects against ethanol-induced damage in human hepatoma SMMC-7721 cells].

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.

[Cinnamaldehyde ofloxacin-3-ylhydrazone induces apoptosis of human hepatocarcinoma SMMC-7721 cells].

This study is to observe the effect of N-(3-phenylallylidene)-6-fluoro-1, 8-(2, 1-propoxy)-7-(4-methylpiperazin-1-yl)-quinolin-4(1H)-one-3-carbonyl hyarazine (FQ16) on apoptosis of hepatocarcinoma SMMC-7721 cells in vitro. With different concentrations of FQ16 at different times used to treat SMMC-7721 cells in vitro, the proliferation of the cells and the inhibition effect of FQ16 on the cell proliferation were examined by MTT assay. Cell apoptosis was determined by Hoechst 33258/PI fluorescence staining, TUNEL and agarose gel electrophoresis method. The effect of FQ16 on topoisomerase II activity was measured by agarose gel electrophoresis using Plasmid pBR322 DNA as the substrate. Mitochondrial membrane potential (MMP, delta psi m) was measured by high content screening image system. The reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the expression changes of Bcl-2 mRNA and Bax mRNA. The caspase-9, caspase-8, caspase-3, p53, Bcl-2 and Bax protein expressions were detected by Western blotting analysis. The results showed that the cell proliferation was inhibited by FQ16 at 0.625 - 10 micromol L(-1) in a time-dose dependent manner. Treatment of SMMC-7721 cells with different concentrations of FQ16 for 24 h increased the percentage of the apoptosis cells obviously (P<0.05), the typical ladder DNA in apoptotic cells and a concomitant dissipation of the mitochondrial membrane potential. Compared with control group, FQ16 influenced obviously DNA topoisomerase II activity, stimulated DNA cleavage and inhibited DNA reunion mediated by topoisomerase II. In addition, FQ16 (3 - 7.39 micromol L(-1)) increased mRNA expression of Bax and protein expression of p53, Bax, caspase-9, caspase-3, separately, and induced cytosolic accumulation of activities caspase-9 and caspase-3, whereas the mRNA and protein expression of Bcl-2 decreased with no change of caspase-8. Therefore it can be concluded that the effects of inhibited topoisomerase II and mitochondrial-dependent pathways were involved in FQ16 induction of apoptosis of SMMC-7721 cells.