cytochrome-c-t and piperine

BACKGROUND Piperine has been reported to inhibit proliferation and induce apoptosis in various cancer cells. This study aimed to explore the efficacy and underlying mechanism of piperine in human gastric cancer. MATERIAL AND METHODS MTT assay was performed to examine the effect of piperine (concentrations of 0-300 μM) on the proliferation of human gastric cancer SNU-16 cells and normal human gastric epithelial GES-1 cells. Flow cytometry and Western blot were used to determine cell apoptosis and the expression level of protein (Cyto C, cleaved PARP, cleaved caspase-3, Bax, Bcl-2, Bad, Bcl-xl, PI3K, pPI3K, Akt, and pAkt), respectively. To further investigate the anti-tumor mechanism of piperine in SNU-16 cells, we used a small-molecule Akt activator SC79 in this study. The in vivo mechanism of piperine against gastric cancer was evaluated using a xenograft tumor model. RESULTS The results showed that piperine inhibited proliferation and induced apoptosis of SNU-16 cells. Piperine upregulated the protein expression of Bax, Bad, Cyto C, cleaved PARP, and cleaved caspase-3, but downregulated the protein expression of Bcl-2, Bcl-xl, pPI3k, and pAkt. However, SC79 reversed the function of piperine on the apoptosis-related proteins. An in vivo study revealed that, compared with the control group, the tumor volume of mice treated with piperine was significantly reduced. Piperine enhanced cleaved caspase-3 expression but decreased Ki-67 expression in a dose-dependent manner. Moreover, the nontoxicity effect of piperine was confirmed by H&E staining analysis in kidney and heart tissues of mice. CONCLUSIONS Our findings suggest that piperine inhibits proliferation and induces apoptosis of human gastric cancer cells through inhibition of the PI3K/Akt signaling pathway.

Topics: Alkaloids; Animals; Antineoplastic Agents; Apoptosis; bcl-Associated Death Protein; bcl-X Protein; Benzodioxoles; Caspase 3; Cell Line, Tumor; Cell Proliferation; Cytochromes c; Gene Expression Regulation, Neoplastic; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Phosphatidylinositol 3-Kinases; Piperidines; Poly(ADP-ribose) Polymerases; Polyunsaturated Alkamides; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Stomach Neoplasms; Tumor Burden; Xenograft Model Antitumor Assays

The rod outer segments (OS) of the retina are specialized organelles where phototransduction takes place. The mitochondrial electron transport complexes I-IV, cytochrome c and Fo F1 -ATP synthase are functionally expressed in the OS disks. Here, we have studied the effect of some polyphenolic compounds acting as inhibitors of mitochondrial ATPase/synthase activity on the OS ectopic Fo F1 - ATP synthase. The mechanism of apoptosis in the OS was also investigated studying the expression of cytochrome c, caspase 9 and 3 and Apaf-1.. We prepared OS from fresh bovine retinae. Semi-quantitative Western blotting, confocal and electron microscopy, and cytofluorimetry were used along with biochemical analyses such as oximetry, ATP synthesis and hydrolysis.. Resveratrol and curcumin plus piperine inhibited ATP synthesis and oxygen consumption in the OS. Epigallocatechin gallate and quercetin inhibited ATP hydrolysis and oxygen consumption in the OS. Malondialdehyde and hydrogen peroxide were produced in respiring OS in the presence of substrates. Cytochrome c was located inside the disk membranes. Procaspase 9 and 3, as well as Apaf-1 were expressed in the OS.. These polyphenolic phytochemicals modulated the Fo F1 -ATP synthase activity of the the OS reducing production of reactive oxygen intermediates by the OS ectopic electron transport chain. Polyphenols decrease membrane peroxidation and cytochrome c release from disks, preventing the induction of caspase-dependent apoptosis in the OS Such effects are relevant in the design of protection against functional impairment of the OS following oxidative stress from exposure to intense illumination.

Topics: Adenosine Triphosphate; Alkaloids; Animals; Benzodioxoles; Caspase 3; Caspase 9; Catechin; Cattle; Curcumin; Cytochromes c; Hydrogen Peroxide; Malondialdehyde; Oxidative Phosphorylation; Oxygen Consumption; Phytochemicals; Piperidines; Polyunsaturated Alkamides; Quercetin; Resveratrol; Rod Cell Outer Segment; Stilbenes

The effect of alkaloid piperine against the toxicity of 1-methyl-4-phenylpyridinium (MPP(+)) in differentiated PC12 cells was assessed. Piperine treatment revealed a differential effect on the cytotoxicity of MPP(+) and had its maximum inhibitory effect at 1 microM. The addition of piperine (0.5-10 microM) significantly reduced the MPP(+)-induced nuclear damage, mitochondrial membrane permeability changes, formation of reactive oxygen species and depletion of GSH. In contrast, piperine at 50-100 microM showed cytotoxicity and exhibited an additive effect against the MPP(+) toxicity. The results indicate that piperine had a differential effect on the cytotoxicity of MPP(+) depending on concentration. Piperine at low concentrations may reduce the MPP(+)-induced viability loss in PC12 cells by suppressing the changes in the mitochondrial membrane permeability, leading to the release of cytochrome c and subsequent activation of caspase-3. The effects may be ascribed to its inhibitory action on the formation of reactive oxygen species and depletion of GSH.

Topics: 1-Methyl-4-phenylpyridinium; Alkaloids; Animals; Benzodioxoles; Caspase 3; Caspases; Cell Death; Cell Membrane Permeability; Cytochromes c; DNA Fragmentation; Glutathione; Lipid Peroxidation; Malondialdehyde; Membrane Potentials; Mitochondria; Mitochondrial Membranes; PC12 Cells; Piperidines; Polyunsaturated Alkamides; Rats; Reactive Oxygen Species; Thiobarbituric Acid Reactive Substances