naphthoquinones and thiazolyl-blue

Many natural and synthetic quinones and naphthoquinones possess a variety of beneficial pharmacological properties. In plants, the cytotoxic properties of quinones serve in their defensive roles against invading bacteria, fungi and parasites. In this regard many quinones as well as polyphenols, exerting generally toxicity at high dosages, are able to induce favorable hormetic responses at a low dosage. The novel chloronaphthoquinone derivative of quercetin (CHNQ) showed a profound cytotoxicity followed by enhancement of intracellular generation of oxidants in human neonatal B-HNF-3 fibroblasts. Its synthetic precursors, quercetin and 2-chloro-3-hydroxy-[1,4]naphthoquinone, failed to induce these effects, and paradoxically, only CHNQ at a low concentration provided partial protection of the cells against oxidative challenge. Thus, the novel quinonoid-polyphenol CHNQ might have a merit in the search for new prospective agents in prevention and management of ageing and ageing-related pathologies.

Topics: Aging; Antioxidants; Apoptosis; Cells, Cultured; Flavonoids; Hormesis; Humans; Hydrogen Peroxide; Immunohistochemistry; Models, Molecular; Naphthoquinones; Necrosis; Neutral Red; Oxidants; Oxidative Stress; Polyphenols; Quinones; Tetrazolium Salts; Thiazoles

β-Lapachone (β-lap) is a novel anticancer agent that selectively induces cell death in human cancer cells, by activation of the NQO1 NAD(P)H dehydrogenase and radical oxygen species (ROS) generation. We characterized the gene expression profile of budding yeast cells treated with β-lap using cDNA microarrays. Genes involved in tolerance to oxidative stress were differentially expressed in β-lap treated cells. β-lap treatment generated reactive oxygen species (ROS), which were efficiently blocked by dicoumarol, an inhibitor of NADH dehydrogenases. A yeast mutant in the mitochondrial NADH dehydrogenase Nde2p was found to be resistant to β-lap treatment, despite inducing ROS production in a WT manner. Most interestingly, DNA damage responses triggered by β-lap were abolished in the nde2Δ mutant. Amino acid biosynthesis genes were also induced in β-lap treated cells, suggesting that β-lap exposure somehow triggered the General Control of Nutrients (GCN) pathway. Accordingly, β-lap treatment increased phosphorylation of eIF2α subunit in a manner dependent on the Gcn2p kinase. eIF2α phosphorylation required Gcn1p, Gcn20p and Nde2p. Gcn2p was also required for cell survival upon exposure to β-lap and to elicit checkpoint responses. Remarkably, β-lap treatment increased phosphorylation of eIF2α in breast tumor cells, in a manner dependent on the Nde2p ortholog AIF, and the eIF2 kinase PERK. These findings uncover a new target pathway of β-lap in yeast and human cells and highlight a previously unknown functional connection between Nde2p, Gcn2p and DNA damage responses.

Topics: Antineoplastic Agents; Dicumarol; eIF-2 Kinase; Enzyme Activation; Humans; Immunoblotting; NAD(P)H Dehydrogenase (Quinone); Naphthoquinones; Oligonucleotide Array Sequence Analysis; Protein Serine-Threonine Kinases; Reactive Oxygen Species; RNA, Small Interfering; Saccharomyces cerevisiae Proteins; Saccharomycetales; Tetrazolium Salts; Thiazoles; Transcriptome

The MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide) assay is a classical method for screening cytotoxic anti-cancer agents. Candidate drugs from the MTT assay need in vivo models to test their efficiency and to assess the absorption, distribution, metabolism, excretion, and toxicity of the drugs. An in vivo screening model could increase the rate of development of anti-cancer drugs. Here, we used zebrafish to screen a library of 502 natural compounds and compared the results with those from an MTT assay of the MCF7 breast cancer cell line. We identified 59 toxic compounds in the zebrafish screen, 21 of which were also identified by the MTT assay, and 28 of which were already known for their anti-cancer and apoptosis-inducing effects. These compounds induced apoptosis and activated the p53 pathway in zebrafish within 3h treatment. Our results indicate that zebrafish is a simple, reliable and highly efficient in vivo tool for cancer drug screening, and could complement the MTT assay.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Camptothecin; Cell Line, Tumor; Coloring Agents; Dimethyl Sulfoxide; Drug Screening Assays, Antitumor; Emodin; Gene Expression; Humans; Lignans; Naphthoquinones; Rotenone; Tetrazolium Salts; Thiazoles; Transcriptional Activation; Tumor Suppressor Protein p53; Zebrafish

Two new naphthoquinones designated as 3alpha-hydroxy-2-(2-hydroxypropan-2-yI)-9alpha-methoxy-2,3,3alpha,9alpha-tetra-hydronaphtho[2,3-b]furan-4,9-dione (callicarpa-quinone A, 1) and 5-hydroxy-2-(2-hydroxypropan-2-yl)naphtho[2,3-b]furan-4,9-dione (callicarpaquinone B, 2) were isolated from the chloroform fraction of Callicarpa maingayi. Three other known compounds, identified as avicequinone-C (3), wodeshiol (4) and paulownin (5), were reported for the first time from this species. The structure elucidation of compounds was established by comprehensive 1D and 2D NMR spectroscopic analyses as well as EIMS, UV and IR spectral data. Compounds 1 and 2 were tested in vitro for their cytotoxic activity against human breast cancer MCF-7cells. Compound 2 exhibited strong cytotoxic activity with an IC50 value of 1.9 +/- 0.2 microM, while 1 showed moderate activity with an IC50 value of 25.0 +/- 4.3 microM.

Topics: Antineoplastic Agents, Phytogenic; Callicarpa; Chloroform; Drug Screening Assays, Antitumor; Magnetic Resonance Spectroscopy; Naphthoquinones; Plant Bark; Plant Extracts; Plant Stems; Solvents; Spectrometry, Mass, Electrospray Ionization; Spectrophotometry, Infrared; Spectrophotometry, Ultraviolet; Tetrazolium Salts; Thiazoles

The aim of this study was to examine the anti-invasion effect of Shikonin on human high-metastatic adenoid cystic carcinoma (ACC-M) cells and to explain the possible molecular mechanism involved.. The ACC-M cells were treated with Shikonin (0, 2.5, 5, 10 μM) for 24 h. The protein levels and gelatinolytic activities of MMP-2 and MMP-9 were analyzed using Western blot and Gelatin zymography test, respectively. Matrigel invasion assays were used to investigate tumor invasive potential and electromobility shift assays were used to determine the activity of NF-κB.. The invasiveness of ACC-M cells was reduced in a dose dependent manner following 24-h treatment of up to 10 μM of the Shikonin at which concentration no cytotoxicity occurred. The protein levels and gelatinolytic activities of MMP-9 were significantly suppressed by increasing Shikonin concentrations. The down-regulation of MMP-9 appeared to be via the inactivation of NF-κB as the treatment with Shikonin suppressed the protein level of phosphate-IkBa, which was accompanied by a decrease in DNA-binding level of the factor.. Shikonin inhibits tumor invasion via downregulation of MMP-9 expression in ACC-M cells. Pharmacologic inhibition of the NF-κB-mediated MMP-9 expression by Shikonin might be a powerful treatment option for ACC patients in future.

Topics: Antineoplastic Agents; Blotting, Western; Carcinoma, Adenoid Cystic; Cell Culture Techniques; Cell Line, Tumor; Cell Survival; Coloring Agents; Dose-Response Relationship, Drug; Down-Regulation; Drugs, Chinese Herbal; Electrophoresis, Polyacrylamide Gel; Humans; I-kappa B Proteins; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Naphthoquinones; Neoplasm Invasiveness; NF-kappa B; Tetrazolium Salts; Thiazoles; Time Factors; Tumor Necrosis Factor-alpha

Plumbagin, a quinonoid found in the plants of the Plumbaginaceae, possesses medicinal properties. In this study we investigated the anti-proliferative and apoptotic activity of plumbagin by using two human colonic cancer cell lines, HT29 and HCT15. IC50 of Plumbagin for HCT15 and HT29 cells (22.5 µM and 62.5 µM, respectively) were significantly different. To study the response of cancer cells during treatment strategies, cells were treated with two different concentrations, 15 µM, 30 µM for HCT15 and 50 µM, 75 µM for HT29 cells. Though activation of NFκB, Caspases-3, elevated levels of TNF-α, cytosolic Cytochrome C were seen in both HCT15 cells HT29 treated with plumbagin, aberrant apoptosis with decreased level of pEGFR, pAkt, pGsk-3β, PCNA and Cyclin D1was observed only in 15 µM and 30 µM plumbagin treated HCT15 and 75 µM plumbagin treated HT29 cells. This suggests that plumbagin induces apoptosis in both HCT15 cells and HT29 treated, whereas, proliferation was inhibited only in 15 µM and 30 µM plumbagin treated HCT15 and 75 µM plumbagin treated HT29 cells, but not in 50 µM plumbagin treated HT29 cells. Expression of COX-2 was decreased in 75 µM plumbagin treated HT29 cells when compared to 50 µM plumbagin treated HT29 cells, whereas HCT15 cells lack COX. Hence the observed resistance to induction of apoptosis in 50 µM plumbagin treated HT29 cells are attributed to the expression of COX-2. In conclusion, plumbagin induces apoptosis in colonic cancer cells through TNF-α mediated pathway depending on expression of COX-2 expression.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Cell Cycle; Cell Line, Tumor; Colonic Neoplasms; Comet Assay; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Flow Cytometry; Gene Expression Regulation, Neoplastic; Humans; Inhibitory Concentration 50; Naphthoquinones; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; Tetrazolium Salts; Thiazoles

A group of styrylazanaphthalenes and azanaphthalenediones were synthesized and tested for their anti-proliferative activity. Most of the compounds were obtained with the use of microwave-assisted synthesis. The lipophilicity of the compounds was measured by RP-HPLC and their anti-proliferative activity was assayed against the human SK-N-MC neuroepithelioma and HCT116 human colon carcinoma cell lines. Active compounds were also tested in clonogenity and comet assays. Several quinazolinone and styrylquinazoline analogues were found to have markedly greater anti-proliferative activity than desferoxamine and cis-platin.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chromatography, High Pressure Liquid; Coloring Agents; Drug Screening Assays, Antitumor; Humans; Lipids; Naphthalenes; Naphthoquinones; Solubility; Styrenes; Tetrazolium Salts; Thiazoles; Tumor Stem Cell Assay

Beta,beta-dimethyl acryl shikonin is an extract from the root of plant Arnebia nobilis which has been shown to possess anti-cancer activity. However, its toxicity limited further development of shikonin as a therapeutic agent. Subsequently, several analogues of beta,beta-dimethyl acryl shikonin were synthesized. One of these analogues, shikonin 93/637 was found to be significantly less toxic compared to shikonin. This study is aimed to determine the cell cycle associated differences in the susceptibility of U937 cells to apoptosis induced by shikonin analogue 93/637 (SA). Lower concentrations of SA (approximately 100 nM) showed no significant changes in cell growth. However, higher concentrations (approximately 500 nM) resulted in growth inhibition of U937 cells after 48 h of treatment with SA as measured by MTT assay. Flow cytometric analysis showed that SA treatment resulted in blocking of cell cycle progression in G1 phase. Decreased expression of Cyclin D, CDK 4 and PCNA was observed with SA treatment corroborating the G1 block. DNA gel electrophoresis showed an oligonucleotide ladder pattern, a distinct characteristic of DNA fragmentation associated with programmed cell death. Ribonuclease protection assay revealed inhibition of bcl2 expression at transcriptional level. SA treatment also resulted in induction of caspase-3 activity. The results suggest the involvement of bcl2 and Caspase-3 in SA induced apoptosis of human U937 cells.

Topics: Apoptosis; Caspase 3; Cell Survival; Cinnamates; DNA Fragmentation; Enzyme Activation; Flow Cytometry; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Naphthoquinones; Neoplasms; Ribonucleases; Tetrazolium Salts; Thiazoles; Transcription, Genetic; U937 Cells

A series of nine new compounds bridged by acyl groups at the 5,8-dihydroxyl group of DHNQ were synthesized and their cytotoxic activity against L1210 and P388 cancer cells was examined. Their antitumor action in mice bearing S-180 cells in the peritoneal cavity was also assessed. Increasing the size of the acyl group (compounds 7-9) up to propyl increased the antitumor activity (T/C value), whereas the cytotoxicity of these compounds was comparable against L1210 (lymphocytic leukemia) and P388 (lymphoid neoplasm) cancer cells. Further increasing in the chain length (compounds 11-15) decreased the potency. Thus, acyl group chains of three carbon atoms is optimal for antitumor activity. The most potent compound of this series was 2-[N-methyl-N-(4-methyl-1,3-benzothiazol-2-yl)aminomethyl]-5,8-dipropylcarbonyloxy-1,4-naphthoquinone (compound 9) with a T/C (%) value of 354.

Topics: Animals; Antineoplastic Agents; Drug Screening Assays, Antitumor; Leukemia L1210; Leukemia P388; Male; Mice; Mice, Inbred ICR; Naphthoquinones; Neoplasm Transplantation; Sarcoma 180; Structure-Activity Relationship; Tetrazolium Salts; Thiazoles

One major pathogenesis in degenerative disorders of the central nervous system (CNS), including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and ischemia, is the oxidative stress induced by reactive oxygen species (ROS). The present study investigated the protective effect of colloidal silver, which is widely marketed as a dietary supplement for diseases like diabetes, AIDS, cancer, and various infections, upon the oxidative brain damage induced by H(2)O(2) or naphthazarin treatment. LDH release from primary cultured astrocytes was enhanced by naphthazarin treatment, and this elevation of the LDH concentration in medium was blocked by colloidal silver treatment. However, hydrogen peroxide was little affected by the colloidal silver. Fluorescence of DCF (peroxides) increased in astrocytes incubated with hydrogen peroxide or naphthazarin compared to the control. When exposed to naphthazarin-induced cells, ROS formation appeared to be reduced by colloidal silver. However, intracellular ROS formation in hydrogen peroxide-treated cells slightly reduced by colloidal silver. These results suggest that colloidal silver has a protective activity against the oxidative stress induced by naphthazarin, but not by hydrogen peroxide.

Topics: Animals; Animals, Newborn; Astrocytes; Cells, Cultured; Cerebral Cortex; Dose-Response Relationship, Drug; Drug Interactions; Hydrogen Peroxide; L-Lactate Dehydrogenase; Naphthoquinones; Oxidants; Rats; Rats, Sprague-Dawley; Reactive Nitrogen Species; Silver Compounds; Tetrazolium Salts; Thiazoles

We consider the cytotoxicity and the protection against oxidative stress for members of the naphthalenediol family and the known antioxidant epigallocatechin gallate (EGCG). Compounds include the 1,2-naphthalenediol (1,2-ND), 1,4-ND, 2,3-ND, 1,8-ND, and 1,4-dipropyl-2,3-naphthalenediol (DPND). The cell line is an adherent clone of rat pheochromocytoma (PC12-AC). Oxidative stress was induced by the peroxyl radical generator AAPH. The relative order of cytotoxicity was 1,4-ND > 1,2-ND > DPND > 2,3-ND > 1,8-ND > EGCG, with EC(50)'s of 15, 40, 160, >250, >250, >>250 muM, respectively. Despite their high toxicity, both 1,4-ND and 1,2-ND showed narrow zones of protective behavior whereas DPND, 2,3-ND and 1,8-ND and especially EGCG showed an extended protective range. The total protection obtained for the combination of cells/oxidative stressor/protective compounds (PC12-AC/AAPH/naphthalenediols) was defined by an integrated measure, the cytoprotective area (CPA). We relate the observed cytotoxicity and CPA to the different electronic structures of the naphthalenediols, characterized by the first and second bond dissociation enthalpies and the pK(a)'s for parent (diol) and semiquinone. Since the 2,3- and 1,8-naphthalenediols do not form quinones, their cytotoxicity is much lower than for the compounds which do. Thus selected members of the naphthalenediol family show promise as antioxidants.

Topics: Animals; Antioxidants; Catechin; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; Free Radicals; Hot Temperature; Hydrogen-Ion Concentration; Inhibitory Concentration 50; Models, Chemical; Naphthols; Naphthoquinones; Oxidation-Reduction; Oxidative Stress; Quinones; Rats; Tetrazolium Salts; Thiazoles; Time Factors

Quinones constitute an important class of naturally occurring compounds. They are found in plants, fungi and bacteria. Large number of quinones has been associated with antitumor, antibacterial, antimalarial and antifungal activities. In this work we describe the isolation, structure determination and the cytotoxic index of a new 1,4-naphthoquinone isolated from the capitula of Paepalanthus latipes.

Topics: Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Eriocaulaceae; Humans; Magnetic Resonance Spectroscopy; Naphthoquinones; Reactive Oxygen Species; Spectrometry, Mass, Electrospray Ionization; Tetrazolium Salts; Thiazoles

Most chemotherapeutic drugs kill cancer cells by indirectly activating checkpoint-mediated apoptosis after creating nonselective damage to DNA or microtubules, which accounts for their toxicity toward normal cells. We seek to target cancer cells by directly activating checkpoint regulators without creating such damage. Here, we show that beta-lapachone selectively induces apoptosis in cancer cells without causing the death of nontransformed cells in culture. This unusual selectivity against cancer cells is preceded by activation of S-phase checkpoint and selective induction of E2F1, a regulator of checkpoint-mediated apoptosis. This study suggests direct checkpoint activation as a strategy against cancer.

Topics: Antibiotics, Antineoplastic; Antineoplastic Agents; Apoptosis; Blotting, Western; Cell Cycle; Cell Cycle Proteins; Cell Death; Cell Division; Cell Line; Cell Transformation, Neoplastic; Coloring Agents; DNA-Binding Proteins; Dose-Response Relationship, Drug; E2F Transcription Factors; E2F1 Transcription Factor; Flow Cytometry; Humans; Models, Biological; Naphthoquinones; Neoplasms; Retinoblastoma Protein; S Phase; Tetrazolium Salts; Thiazoles; Transcription Factors; Tumor Cells, Cultured