Attenuation of autophagy flux by 6-shogaol sensitizes human liver cancer cells to TRAIL-induced apoptosis via p53 and ROS.

Tumor necrosis factor (TNF)­related apoptosis­inducing ligand (TRAIL) is a member of the TNF superfamily and is an antitumor drug that induces apoptosis in tumor cells with minimal or no effects on normal cells. Here, it is demonstrated that 6­shogaol (6­sho), a bioactive component of ginger, exerted anti­inflammatory and anticancer properties, attenuated tumor cell propagation and induced TRAIL­mediated cell death in liver cancer cells. The current study identified a potential pathway by revealing that TRAIL and 6­sho or chloroquine acted together to trigger reactive oxygen species (ROS) production, to upregulate tumor­suppressor protein 53 (p53) expression and to change the mitochondrial transmembrane potential (MTP). Treatment with N­acetyl­L­cysteine reversed these effects, restoring the MTP and attenuated ROS production and p53 expression. Interestingly, treatment with 6­sho increased p62 and microtubule­associated proteins 1A/1B light chain 3B­II levels, indicating an inhibited autophagy flux. In conclusion, attenuation of 6­sho­induced autophagy flux sensitized cells to TRAIL­induced apoptosis via p53 and ROS, suggesting that the administration of TRAIL in combination with 6­sho may be a suitable therapeutic method for the treatment of TRAIL­resistant Huh7 liver cells.

Galangin induces apoptosis of hepatocellular carcinoma cells via the mitochondrial pathway.

AIM: To investigate the mechanism by which galangin, a polyphenolic compound derived from medicinal herbs, induces apoptosis of hepatocellular carcinoma (HCC) cells. METHODS: The 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay was used to measure cell viability. Apoptosis was evaluated by in situ uptake of propidium iodide and Hoechst 33258 and was then detected by fluorescence microscopy. Protein expressions were detected by Western blotting. To confirm the apoptotic pathway mediated by galangin, cells were transfected by bcl-2 gene to overexpress Bcl-2 or siRNA to down-regulate Bcl-2 expression. RESULTS: Galangin (46.25-370.0 micromol/L) exerted an anti-proliferative effect, induced apoptosis, and decreased mitochondrial membrane potential in a dose and time-dependent manner. Treatment with galangin induced apoptosis by translocating the pro-apoptotic protein Bax to the mitochondria, which released apoptosis-inducing factor and cytochrome c into the cytosol. Overexpression of Bcl-2 attenuated galangin-induced HepG2 cell apoptosis, while decreasing Bcl-2 expression enhanced galangin-induced cell apoptosis. CONCLUSION: Our data suggests that galangin mediates apoptosis through a mitochondrial pathway, and may be a potential chemotherapeutic drug for the treatment of HCC.

Mutagenic and antimutagenic effects of the traditional herb used for treating erectile dysfunction, Butea superba Roxb.

Butea superba is a traditional tuberous Thai plant enriched with flavonoids that is used for treating erectile dysfunction. We investigated the mutagenic and antimutagenic potentials of a B. superba extract by using the pre-incubation method of the Ames test. Salmonella typhimurium strains TA 98 and TA 100 were applied as the tester strains in the presence and absence of an S9 mixture. Prior to the mutagenic and antimutagenic tests, the survival of the tester strains was measured by treating with the B. superba extract. The results show that the B. superba extract exhibited dose-dependent cytotoxic effects. Data from the Ames test revealed that the B. superba extract to be non-mutagenic in the presence and absence of the S9 mixture. In contrast, the B. superba extract showed antimutagenic potential towards either or both of the tested mutagens: 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide (AF-2) and benzo(a)pyrene (B(a)P) in the respective presence and absence of the S9 mixture, respectively. The plant antimutagenic activity was confirmed by a rec assay. A further study by micronucleus test demonstrated that the B. superba extract at the maximum loading volume could induce acute micronucleus formation in the tested animals. The in vitro mutagenic and antimutagenic assays confirmed the safe consumption of B. superba products at low dose (not more than 781.25 microg/ml of the plant extract), but the in vivo genotoxic assay demonstrated the unsafe consumption at a high dose (300 mg/kg of the BW plant extract or 16 g/kg of the BW plant powder).

Cytotoxic and genotoxic butanolides and lignans from Aiouea trinervis.

The ethanolic extracts from the roots, the underground trunk and the leaves of Aiouea trinervis were active in the brine shrimp (Artemia salina) lethality assay (LD (50): 1.93, 0.92 and 262.1 microg/mL, respectively). Fractionation of the extracts led to the isolation of four butanolides, namely (-)-epilitsenolides C (2) and C (1) ( 1 and 2), isoobtusilactone A ( 3) and obtusilactone A ( 4), two of which ( 1 and 2) are reported for the first time as genuine natural products. The lignans (+)-sesamin ( 5) and (+)-methylpiperitol ( 6) and polyprenol-12 ( 7) were isolated as well. Their structures were determined with spectral methods (1D-, 2D-NMR and MS). Compounds 1, 2, 3, 5 and 6 were tested for their cytotoxic activities in Hep (2) human cancer cells. The butanolides 2 and 3 were the most active (IC (50): 5.96 microg/mL and 4.95 microg/mL, respectively) whereas the other compounds showed moderate IC (50) values ranging from 12.20 microg/mL to 25.64 microg/mL. The genotoxic properties of the crude ethanolic extracts and of compounds 3 and 5 were also evaluated in this study on CHO K1 and HTC mammalian cells with single-cell gel electrophoresis (comet assay). The crude extracts as well as the compounds tested induced DNA migration in this assay, which was indicative of DNA damage (genotoxic effect).

Mutagenic and antimutagenic potential of the medicinal plants M. laevigata and C. xanthocarpa.

Aqueous extracts of medicinal plants (Mikania laevigata and Campomanesia xanthocarpa) were screened for the presence of mutagenic activity in the Salmonella/microsome assay. The extracts of Campomanesia xanthocarpa showed frameshift (TA97a strain) signs of mutagenic activity without exogenous metabolism (S9 fraction). The infusions of Mikania laevigata, negative for mutagenic activity, showed high percentages of inhibition of mutagenesis induced by mutagens 2AF (2-amino fluorene), in the presence of exogenous metabolism (S9 fraction), for frameshift (TA98) and base pair substitution (TA100) lesions. In addition, these inhibitions were observed against mutagen SAZ (sodium azide) in assays with the TA100 strain, without exogenous metabolism (S9 fraction). A synergistic effect was also observed in frameshift mutagenic events, with direct action in the presence of 4NQO (4-oxide-1-nitroquinoline) and a tendency to a low percentage of action enhancement, in the presence of the 2AF mutagen. The variable responses observed in the extract assays show the potentials for interaction of the different active principles in genetic material.

Genotoxicidad en la Tilapia Roja (Orechromis SP) inducida por el metavanadato de amonio / Genotoxicity in the red Tilapia(Orechrammomis SP) induced by ammonium methavadanate

La versatilidad en el uso del Vanadio, incluye a la industria del acero, de la cerámica, la industria de catalizadores químicos, pinturas, insecticidas, materiales fotográficos y en la fabricación de superconductores. Los efectos toxicológicos de los compuestos de vanadio son muy amplios ya que es capaz de inhibir un elevado numero de enzimas, siendo su acción dependiente de su valencia. El vanadio al igual que otros metales se bioacumula y tiene un largo tiempo de vida media en los seres vivos, su contaminación debería tener mayor importancia en nuestro medio, ya que el estado Zulia es una región petrolera por excelencia y el petróleo pesado y el carbón, son hidrocarburos que están en el lago de Maracaibo y en algunas áreas de sus cuencas. En este estudio se realizaron ensayos de genotoxicidad con especies del género Tilapia(orechromis SP) con el objetivo de determinar alteraciones morfológicas e histológicas (teratogénesis) en los descendientes de hembras expuestas a 0,75ppm de metavadanato de amonio (MVA) y cuyos resultados fueron comparados con los controles, encontrándose diferencias significativas para un nivel de confianza del 5 por ciento .La exposición al vanadio de Tilapias hembras correspondió a un período de 120 días, conducido en tanques de 1000 L de capacidad para su reproducción con macho no expuestos. Las evaluaciones de los daños incluyen además de la descendencia a los progenitores. Los resultados demostraron la acción genotóxica del vanadio a la concentración subletal de 0.75 ppm para peces del género Tilapia.