stilbenes and benzyloxycarbonylvalyl-alanyl-aspartyl-fluoromethyl-ketone

Topics: Amino Acid Chloromethyl Ketones; Antioxidants; Apoptosis; Caspase Inhibitors; Cell Line, Tumor; Cell Proliferation; Cell Survival; Drug Resistance, Neoplasm; Glucosyltransferases; Humans; Inhibitory Concentration 50; Jurkat Cells; K562 Cells; PC-3 Cells; Phosphotransferases (Alcohol Group Acceptor); Resveratrol; Stilbenes; U937 Cells

Resveratrol is known to be an effective chemo-preventive phytochemical against multiple tumor cells. However, the increasing drug resistance avoids the cancer treatment in oral cavity cancer. In this study, we investigated the oral antitumor activity of resveratrol and its mechanism in cisplatin-resistant human oral cancer CAR cells. Our results demonstrated that resveratrol had an extremely low toxicity in normal oral cells and provoked autophagic cell death to form acidic vesicular organelles (AVOs) and autophagic vacuoles in CAR cells by acridine orange (AO) and monodansylcadaverine (MDC) staining. Either DNA fragmentation or DNA condensation occurred in resveratrol-triggered CAR cell apoptosis. These inhibitors of PI3K class III (3-MA) and AMP-activated protein kinase (AMPK) (compound c) suppressed the autophagic vesicle formation, LC3-II protein levels and autophagy induced by resveratrol. The pan-caspase inhibitor Z-VAD-FMK attenuated resveratrol-triggered cleaved caspase-9, cleaved caspase-3 and cell apoptosis. Resveratrol also enhanced phosphorylation of AMPK and regulated autophagy- and pro-apoptosis-related signals in resveratrol-treated CAR cells. Importantly, resveratrol also stimulated the autophagic mRNA gene expression, including Atg5, Atg12, Beclin-1 and LC3-II in CAR cells. Overall, our findings indicate that resveratrol is likely to induce autophagic and apoptotic death in drug-resistant oral cancer cells and might become a new approach for oral cancer treatment in the near future.

Topics: Amino Acid Chloromethyl Ketones; AMP-Activated Protein Kinases; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Autophagy-Related Protein 12; Autophagy-Related Protein 5; Beclin-1; Caspase 3; Caspase 9; Cell Line, Tumor; Cisplatin; DNA Fragmentation; Drug Resistance, Neoplasm; Humans; Microtubule-Associated Proteins; Mouth Neoplasms; Phosphorylation; Proto-Oncogene Proteins c-akt; Resveratrol; RNA, Messenger; Signal Transduction; Stilbenes; TOR Serine-Threonine Kinases

Previously, we reported that (E)-8-acetoxy-2-[2-(3,4-diacetoxyphenyl)ethenyl]-quinazoline (8-ADEQ), a synthetic analogue of resveratrol had anti-inflammatory and G2/M cell cycle arrest activities, but the underlying molecular mechanism of cytotoxic effects of this compound was not determined. In this study, 8-ADEQ displayed potent cytotoxicity and triggered apoptosis in HL-60 cells as evidenced by DNA fragmentation, DNA ladder formation, and the externalization of Annexin V-targeted phosphatidylserine residues in HL-60 cells. In addition, 8-ADEQ triggered activation of caspases-8, -9, -6 and -3 and cleavage of their substrates such as poly(ADP-ribose) polymerase (PARP). Moreover, 8-ADEQ induced loss of mitochondrial membrane potential (MMP) and release of cytochrome c to the cytosol. Caspase-3 inhibitor (z-DEVD-fmk), caspase-8 inhibitor (z-IETD-fmk), caspase-9 inhibitor (z-LEHD), and broad caspase inhibitor (z-VAD‑fmk) significantly suppressed the 8-ADEQ-induced DNA fragmentation. Interestingly, pretreatment with z-IETD-fmk, a caspase-8 inhibitor, completely abolished 8-ADEQ-induced caspase-3 and -9 activation, and subsequent DNA fragmentation. 8-ADEQ also increased the expression of Fas, Fas-associated death domain (FADD) and FasL, and formation of death-inducing signaling complex (DISC). Further analysis revealed that 8-ADEQ-induced apoptosis was mediated by upregulation of reactive oxidative species (ROS) generation. Taken together, our data indicated that 8-ADEQ-stimulated apoptosis in HL-60 leukemia cells is due to a Fas-mediated caspase-8-dependent pathway via ROS generation, but also, to a lesser extent cytochrome c release and caspase-9 activation.

Topics: Amino Acid Chloromethyl Ketones; Apoptosis; Caspase 3; Caspase 8; Caspase 9; Caspase Inhibitors; Cytochromes c; Fas Ligand Protein; HL-60 Cells; Humans; Membrane Potential, Mitochondrial; Oligopeptides; Poly(ADP-ribose) Polymerases; Quinazolines; Resveratrol; Stilbenes

Chronic neurodegenerative syndromes such as Alzheimer's and Parkinson's diseases, or acute syndromes such as ischemic stroke or traumatic brain injuries are characterized by early synaptic collapse which precedes axonal and neuronal cell body degeneration and promotes early cognitive impairment in patients. Until now, neuroprotective strategies have failed to impede the progression of neurodegenerative syndromes. Drugs preventing the loss of cell body do not prevent the cognitive decline, probably because they lack synapto-protective effects. The absence of physiologically realistic neuronal network models which can be easily handled has hindered the development of synapto-protective drugs suitable for therapies. Here we describe a new microfluidic platform which makes it possible to study the consequences of axonal trauma of reconstructed oriented mouse neuronal networks. Each neuronal population and sub-compartment can be chemically addressed individually. The somatic, mid axon, presynaptic and postsynaptic effects of local pathological stresses or putative protective molecules can thus be evaluated with the help of this versatile "brain on chip" platform. We show that presynaptic loss is the earliest event observed following axotomy of cortical fibers, before any sign of axonal fragmentation or post-synaptic spine alteration. This platform can be used to screen and evaluate the synapto-protective potential of several drugs. For instance, NAD⁺ and the Rho-kinase inhibitor Y27632 can efficiently prevent synaptic disconnection, whereas the broad-spectrum caspase inhibitor zVAD-fmk and the stilbenoid resveratrol do not prevent presynaptic degeneration. Hence, this platform is a promising tool for fundamental research in the field of developmental and neurodegenerative neurosciences, and also offers the opportunity to set up pharmacological screening of axon-protective and synapto-protective drugs.

Topics: Amides; Amino Acid Chloromethyl Ketones; Animals; Axons; Dendrites; Embryo, Mammalian; Enzyme Inhibitors; Mice; Microfluidics; Microscopy, Fluorescence; Models, Neurological; NAD; Nerve Net; Neurodegenerative Diseases; Primary Cell Culture; Pyridines; Resveratrol; Stilbenes; Synapses

Autophagy that is induced by starvation or cellular stress can enable cancer cell survival by sustaining energy homeostasis and eliminating damaged organelles and proteins. In response to stress, cancer cells have been reported to accumulate the protein p62/SQSTM1 (p62), but its role in the regulation of autophagy is controversial. Here, we report that the plant phytoalexin resveratrol (RSV) triggers autophagy in imatinib-sensitive and imatinib-resistant chronic myelogenous leukemia (CML) cells via JNK-dependent accumulation of p62. JNK inhibition or p62 knockdown prevented RSV-mediated autophagy and antileukemic effects. RSV also stimulated AMPK, thereby inhibiting the mTOR pathway. AMPK knockdown or mTOR overexpression impaired RSV-induced autophagy but not JNK activation. Lastly, p62 expression and autophagy in CD34+ progenitors from patients with CML was induced by RSV, and disrupting autophagy protected CD34+ CML cells from RSV-mediated cell death. We concluded that RSV triggered autophagic cell death in CML cells via both JNK-mediated p62 overexpression and AMPK activation. Our findings show that the JNK and AMPK pathways can cooperate to eliminate CML cells via autophagy.

Topics: Adaptor Proteins, Signal Transducing; Amino Acid Chloromethyl Ketones; AMP-Activated Protein Kinases; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Autophagy; Benzamides; Blotting, Western; Caspase Inhibitors; Caspases; Cell Survival; Drug Resistance, Neoplasm; Humans; Imatinib Mesylate; JNK Mitogen-Activated Protein Kinases; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Macrolides; Microscopy, Confocal; Microscopy, Electron; Piperazines; Pyrimidines; Resveratrol; RNA Interference; Sequestosome-1 Protein; Stilbenes; Tumor Cells, Cultured; Vacuolar Proton-Translocating ATPases

Resveratrol (trans-3,4',5-trihydroxystilbene) is a naturally occurring polyphenolic compound highly enriched in grapes, peanuts, red wine, and a variety of food sources. Resveratrol has antiinflammatory and antioxidant properties, and also has potent anticancer properties. Human glioma U251 cells were used to understand the molecular mechanisms by which resveratrol acts as an anticancer agent, since glioma is a particularly difficult cancer to treat and eradicate. Our data show that resveratrol induces dose- and time-dependent death of U251 cells, as measured by lactate dehydrogenase release and internucleosomal DNA fragmentation assays. Resveratrol induces activation of caspase-3 and increases the cleavage of the downstream caspase substrate, poly(ADP-ribose) polymerase. Resveratrol-induced DNA fragmentation can be completely blocked by either a general caspase inhibitor (Z-VAD-FMK) or a selective caspase-3 inhibitor (Z-DEVD-FMK), but not by a selective caspase-1 inhibitor. Resveratrol induces cytochrome c release from mitochondria to the cytoplasm and activation of caspase-9. Resveratrol also increases expression of proapoptotic Bax and its translocation to the mitochondria. Resveratrol inhibits U251 proliferation, as measured by MTS assay [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt], and induces G0/G1 growth arrest, as determined by flow cytometry. The cyclin-dependent kinase inhibitor, olomoucine, prevents cell cycle progression and resveratrol-induced apoptosis. These results suggest that multiple signaling pathways may underlie the apoptotic death of U251 glioma induced by resveratrol, which warrants further exploration as an anticancer agent in human glioma.

Topics: Amino Acid Chloromethyl Ketones; Antineoplastic Agents, Phytogenic; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Caspase 3; Caspase 9; Caspase Inhibitors; Caspases; Cell Cycle; Cell Line, Tumor; Cytochromes c; Cytoplasm; DNA Fragmentation; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Flavonoids; Glioma; Humans; Kinetin; L-Lactate Dehydrogenase; Phenols; Poly(ADP-ribose) Polymerases; Polyphenols; Proto-Oncogene Proteins c-bcl-2; Purines; Resveratrol; Signal Transduction; Stilbenes; Subcellular Fractions; Time Factors; Up-Regulation

3, 4'-Dimethoxy-5-hydroxystilbene (DMHS) is a hydroxystilbene compound obtained by methylation and acid hydrolysis of piceid (resveratrol-3-O-glucoside) from Polygonum cuspidatum. Herein, we report that DMHS induces programmed cell death or apoptosis in human promyelocytic leukemic HL-60 cells. We found that treatment of HL-60 cells with DMHS suppressed the cell growth in a concentration-dependent manner with an IC50 value of 25 microM. DMHS increased internucleosomal DNA fragmentation in a time-dependent manner. The cell death by DMHS was partially prevented by the caspase inhibitor, zVAD-fmk. DMHS caused activation of caspases such as caspase-3, -8, and -9. Immunoblot experiments revealed that DMHS-induced apoptosis was associated with the induction of Bax expression. The release of cytochrome c from mitochondria into the cytosol was increased in response to DMHS. Taken together, our present results indicated that DMHS leads to apoptotic cell death in HL-60 cells through increased Bax expression and release of cytochrome c into cytosol and may be considered as a good candidate for a cancer chemopreventive agent in humans.

Topics: Amino Acid Chloromethyl Ketones; Antineoplastic Agents, Phytogenic; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Caspase 3; Caspase 8; Caspase 9; Caspase Inhibitors; Caspases; Cell Division; Cytochrome c Group; DNA Fragmentation; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Gene Expression; Glucosides; HL-60 Cells; Humans; Mitochondria; Plant Extracts; Polygonum; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Stilbenes

The molecular basis for the sensitivity of tumor cells to chemopreventive natural food compounds and commonly used chemotherapeutic agents is not well understood, not least because studies are frequently confounded by the diversity among cell lines or rely on experimental protein overexpression. Here we investigated the effects of n-butyrate, a cancer-preventive short-chain fatty acid produced by anaerobic bacteria in the gastrointestinal tract, on the human wild-type p53 and p21 expressing HCT116 colon carcinoma cell line and on HCT116 cells with either p53 or p21 alleles inactivated by homologous recombination. The effects of n-butyrate were then compared with those elicited by cytotoxic drugs and the natural chemopreventive phytoalexin of wine and grapes, resveratrol. We document that physiological concentrations of n-butyrate stimulate p21 expression and induce apoptosis independently of p53, and that the absence of p21 increases apoptosis drastically. The apoptosis is mediated through the mitochondria and is accompanied by mitochondrial proliferation and membrane potential changes. Adriamycin, etoposide, cisplatinum, colcemid and resveratrol induce distinct cellular responses; however, absence of p21 favors apoptosis-induction by adriamycin, etoposide and colcemid. Thus, control of p21 expression may support chemoprevention and certain tumor therapies.

Topics: Adenocarcinoma; Alleles; Amino Acid Chloromethyl Ketones; Anticarcinogenic Agents; Antineoplastic Agents; Apoptosis; Benzothiazoles; Butyrates; Cisplatin; Colonic Neoplasms; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Cysteine Proteinase Inhibitors; Demecolcine; Doxorubicin; Drug Resistance, Neoplasm; Etoposide; Fluorouracil; Gene Expression Regulation, Neoplastic; Genes, p53; Humans; Intracellular Membranes; Membrane Potentials; Mitochondria; Neoplasm Proteins; Recombination, Genetic; Resveratrol; Stilbenes; Thiazoles; Toluene; Tumor Cells, Cultured; Tumor Suppressor Protein p53