stilbenes and Necrosis

Vascular targeting agents (VTAs) for the treatment of cancer are designed to cause a rapid and selective shutdown of the blood vessels of tumors. Unlike antiangiogenic drugs that inhibit the formation of new vessels, VTAs occlude the pre-existing blood vessels of tumors to cause tumor cell death from ischemia and extensive hemorrhagic necrosis. Tumor selectivity is conferred by differences in the pathophysiology of tumor versus normal tissue vessels (e.g., increased proliferation and fragility, and up-regulated proteins). VTAs can kill indirectly the tumor cells that are resistant to conventional antiproliferative cancer therapies, i.e., cells in areas distant from blood vessels where drug penetration is poor, and hypoxia can lead to radiation and drug resistance. VTAs are expected to show the greatest therapeutic benefit as part of combined modality regimens. Preclinical studies have shown VTA-induced enhancement of the effects of conventional chemotherapeutic agents, radiation, hyperthermia, radioimmunotherapy, and antiangiogenic agents. There are broadly two types of VTAs, small molecules and ligand-based, which are grouped together, because they both cause acute vascular shutdown in tumors leading to massive necrosis. The small molecules include the microtubulin destabilizing drugs, combretastatin A-4 disodium phosphate, ZD6126, AVE8062, and Oxi 4503, and the flavonoid, DMXAA. Ligand-based VTAs use antibodies, peptides, or growth factors that bind selectively to tumor versus normal vessels to target tumors with agents that occlude blood vessels. The ligand-based VTAs include fusion proteins (e.g., vascular endothelial growth factor linked to the plant toxin gelonin), immunotoxins (e.g., monoclonal antibodies to endoglin conjugated to ricin A), antibodies linked to cytokines, liposomally encapsulated drugs, and gene therapy approaches. Combretastatin A-4 disodium phosphate, ZD6126, AVE8062, and DMXAA are undergoing clinical evaluation. Phase I monotherapy studies have shown that the agents are tolerated with some demonstration of single agent efficacy. Because efficacy is expected when the agents are used with conventional chemotherapeutic drugs or radiation, the results of Phase II combination studies are eagerly awaited.

Topics: Angiogenesis Inhibitors; Antibodies, Monoclonal; Cell Division; Clinical Trials as Topic; Diphosphates; Genetic Therapy; Humans; Hypoxia; Immunotoxins; Ligands; Models, Biological; Necrosis; Neoplasms; Organophosphorus Compounds; Peptides; Radioimmunotherapy; Stilbenes; Time Factors; Up-Regulation; Xanthones

This study investigated the effects and molecular mechanisms of ε-viniferin and α-viniferin in non-small cell lung cancer cell line A549, melanoma cell line A2058, and osteosarcoma cell lines HOS and U2OS. Results showed ε-viniferin having antiproliferative effects on HOS, U2OS, and A549 cells. Compared with ε-viniferin at the same concentration, α-viniferin had higher antiproliferative effects on HOS cells, but not the same effect on U2OS and A549 cells. Lower dose combination of α-viniferin and ε-viniferin had more synergistic effects on A549 cells than either drug alone. α-Viniferin induced apoptosis in HOS cells by decreasing expression of phospho-c-Jun-N-terminal kinase 1/2 (p-JNK1/2) and increasing expression of cleaved Poly (ADP-ribose) polymerase (PARP), whereas α-viniferin in combination with ε-viniferin induced apoptosis in A549 cells by decreasing expression of phospho-protein kinase B (p-AKT) and increasing expression of cleaved PARP and cleaved caspase-3. ε-Viniferin and α-viniferin have not been studied using in vivo tumor models for cancer. This research is the first showing that ε-viniferin treatment resulted in significant inhibition of tumor growth in A549-cell xenograft-bearing nude mice compared with the control group. Consequently, ε-viniferin and α-viniferin may prove to be new approaches and effective therapeutic agents for osteosarcoma and lung cancer treatment.

Topics: A549 Cells; Antineoplastic Agents; Apoptosis; Benzofurans; Carcinoma, Non-Small-Cell Lung; Humans; Lung Neoplasms; Necrosis; Osteosarcoma; Stilbenes

Visualization of tumor necrosis can determine tumor response to therapy. Our previous study showed that the rhein-based magnetic resonance imaging (MRI) contrast agent with alkane linker (GdL. Three rhein-based MRI agents were synthesized with a tetracarbon ether (GdP1), a hexacarbon ether (GdP2), and a lysine (GdP3) linker, respectively. Their octanol-water partition coefficients (log P) and cytotoxicity were determined. Necrosis avidity of the leading agent was explored on HepG2 cells and ischemia reperfusion-induced liver necrosis (IRLN) rats by MRI. The effect of visualization of tumor necrosis was tested on nude mice with W256 tumor treated by combretastatin-A4 phosphate (CA4P). DNA binding assays were applied to evaluate the possible necrosis-avidity mechanism of the leading agent.. The log P of three agents (- 1.66 ± 0.09, - 1.74 ± 0.01, - 1.95 ± 0.01) decreased when compared with GdL. GdP1 may serve as a potential candidate for early evaluation of tumor response to CA4P treatment.

Topics: Animals; Anthraquinones; Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Contrast Media; Disease Models, Animal; Drug Design; Humans; Liver Neoplasms, Experimental; Magnetic Resonance Imaging; Male; Mice; Mice, Nude; Necrosis; Rats; Rats, Sprague-Dawley; Stilbenes; Tissue Distribution

A series of novel 1,4-diaryl-2-azetidinone analogues of combretastatin A-4 (CA-4) have been designed, synthesised and evaluated in vitro for antiproliferative activity, antiapoptotic activity and inhibition of tubulin polymerisation. Glucuronidation of CA-4 by uridine 5-diphosphoglucuronosyl transferase enzymes (UGTs) has been identified as a mechanism of resistance in cancer cells. Potential sites of ring B glucuronate conjugation are removed by replacing the B ring meta-hydroxy substituent of selected series of β-lactams with alternative substituents e.g. F, Cl, Br, I, CH

Topics: Antineoplastic Agents; Apoptosis; beta-Lactams; Binding Sites; Cell Line, Tumor; Cell Proliferation; Drug Screening Assays, Antitumor; G2 Phase Cell Cycle Checkpoints; HEK293 Cells; Humans; Microsomes, Liver; Molecular Docking Simulation; Molecular Structure; Necrosis; Protein Binding; Stilbenes; Survivin; Tubulin; Tubulin Modulators

This study aimed to synthesize a necrosis-avid agent using rhein as a precursor and labeled with gallium-68 (Ga-68) for positron emission tomography/computed tomography (PET/CT) imaging, to evaluate response to anticancer treatment in a mouse model.

Topics: Animals; Anthraquinones; Antineoplastic Agents, Phytogenic; Cattle; Cell Line, Tumor; DNA; Gallium Radioisotopes; Heterocyclic Compounds, 1-Ring; Male; Mice; Necrosis; Positron Emission Tomography Computed Tomography; Radiopharmaceuticals; Sarcoma 180; Stilbenes; Tissue Distribution; Treatment Outcome

Noninvasive imaging of cell necrosis can provide an early evaluation of tumor response to treatments. Here, we aimed to design and synthesize a novel diindole-based magnetic resonance imaging (MRI) contrast agent (Gd-bis-DOTA-diindolylmethane, Gd-DIM) for assessment of tumor response to therapy at an early stage.. The oil-water partition coefficient (Log P) and relaxivity of Gd-DIM were determined in vitro. Then, its necrosis avidity was examined in necrotic cells in vitro and in rat models with microwave ablation-induced muscle necrosis (MAMN) and ischemia reperfusion-induced liver necrosis (IRLN) by MRI. Visualization of tumor necrosis induced by combretastatin A-4 disodium phosphate (CA4P) was evaluated in rats bearing W256 orthotopic liver tumor by MRI. Finally, DNA binding assay was performed to explore the possible necrosis-avidity mechanism of Gd-DIM.. The Log P value and T1 relaxivity of Gd-DIM is - 2.15 ± 0.01 and 6.61 mM. Gd-DIM may serve as a promising necrosis-avid MRI contrast agent for early assessment of tumor response to therapy.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Contrast Media; Disease Models, Animal; Liver Neoplasms; Lung Neoplasms; Magnetic Resonance Imaging; Male; Necrosis; Rats; Rats, Sprague-Dawley; Stilbenes

Activating alternative cell death pathways, including autophagic cell death, is a promising direction to overcome the apoptosis resistance observed in various cancers. Yet, whether autophagy acts as a death mechanism by over consumption of intracellular components is still controversial and remains undefined at the ultrastructural and the mechanistic levels. Here we identified conditions under which resveratrol-treated A549 lung cancer cells die by a mechanism that fulfills the previous definition of autophagic cell death. The cells displayed a strong and sustained induction of autophagic flux, cell death was prevented by knocking down autophagic genes and death occurred in the absence of apoptotic or necroptotic pathway activation. Detailed ultrastructural characterization revealed additional critical events, including a continuous increase over time in the number of autophagic vacuoles, in particular autolysosomes, occupying most of the cytoplasm at terminal stages. This was followed by loss of organelles, disruption of intracellular membranes including the swelling of perinuclear space and, occasionally, a unique type of nuclear shedding. A signalome-wide shRNA-based viability screen was applied to identify positive mediators of this type of autophagic cell death. One top hit was GBA1, the Gaucher disease-associated gene, which encodes glucocerebrosidase, an enzyme that metabolizes glucosylceramide to ceramide and glucose. Interestingly, glucocerebrosidase expression levels and activity were elevated, concomitantly with increased intracellular ceramide levels, both of which correlated in time with the appearance of the unique death characteristics. Transfection with siGBA1 attenuated the increase in glucocerebrosidase activity and the intracellular ceramide levels. Most importantly, GBA1 knockdown prevented the strong increase in LC3 lipidation, and many of the ultrastructural changes characteristic of this type of autophagic cell death, including a significant decrease in cytoplasmic area occupied by autophagic vacuoles. Together, these findings highlight the critical role of GBA1 in mediating enhanced self-consumption of intracellular components and endomembranes, leading to autophagic cell death.

Topics: A549 Cells; Apoptosis; Autophagy; Gene Knockdown Techniques; Glucosylceramidase; HT29 Cells; Humans; Lysosomes; Necrosis; Resveratrol; RNA Interference; Signal Transduction; Sphingolipids; Stilbenes

Acute carbon monoxide (CO) poisoning causes neurotoxicity through induction of necrosis, apoptosis, lipid peroxidation and oxidative stress. Resveratrol (RES) is a natural polyphenolic phytoalexin that exhibits neuroprotective effects in ischemia/reperfusion due to its anti-apoptotic, anti-necrotic and strong anti-oxidant properties as well as its ability to activate pro-survival pathways. In this study, rats were exposed to CO 3000 ppm for 1 h. Immediately after poisoning and on the next four consecutive days, RES (1, 5 and 10 mg/kg) was administered intraperitoneally. On the fifth day, animals' brains were excised, and necrosis, lipid peroxidation level and the level of Akt, BAX and BCL2 expression were evaluated. The results showed that RES 10 mg/kg significantly reduced lipid peroxidation, but RES 1 and 5 mg/kg had no significant effect on this parameter. Furthermore, RES 5 and 10 mg/kg significantly increased Akt expression level, while BAX/BCL2 ratio was reduced by RES 1, 5 and 10 mg/kg. Moreover, RES reduced necrotic foci in the brain, but the best results were seen following treatment with RES 10 mg/kg. In summary, RES showed neuroprotective effect in CO-poisoned rats as it decreased necrosis and BAX/BCL2 ratio and increased Akt expression levels. Copyright © 2017 John Wiley & Sons, Ltd.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Brain; Carbon Monoxide Poisoning; Lipid Peroxidation; Male; Necrosis; Neuroprotective Agents; Oxidative Stress; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Wistar; Resveratrol; Stilbenes

Epidemiological and experimental evidences have shown cancer as a leading cause of death worldwide. Although the folklore use of plants as a reliable source of health-restoring principles is well-documented, the search for more of such plants that are active against diseases, such as cancer, continues. We report here a laboratory-based evidence of the relevance of an ethanol leaf extract of Anogeissus leiocarpus (A2L) in comparison with resveratrol, a natural polyphenol, in cancer therapy.. The quantitative assessment of flavonoid and phenolic contents involved quercetin and gallic acid as standards, respectively were determined using spectrophotometry. Cytotoxicity was determined fluorometrically using propidium-iodide-staining method. Antioxidant status, adenosine triphosphate (ATP) levels, caspase activities and mitochondrial integrity were assessed using fluorometry/luminometry.. The antioxidant assay demonstrated that A2L possesses a strong antioxidant capacity as compared with the reference compounds, ascorbic acid and butylated hydroxytoluene. This is further buttressed by the significantly high level of phenolics obtained in the quantitative assessment of the extract. A 72-h post-treatment examination indicated that both A2L and resveratrol modulate the proliferation of HepG2 liver carcinoma cells in a time- and concentration-dependent manner. Determination of the total nuclei area, propidium-iodide negative and positive nuclei areas all further buttress the modulation of cell proliferation by A2L and resveratrol with the indication that the observed cell death is due to apoptosis and necrosis at lower and higher concentrations of treatments respectively. At lower concentrations (0.39-3.13 μg/mL), resveratrol possesses higher tendencies to activate caspases 3 and 7. Bioenergetically, both resveratrol and A2L do not adversely affect the cells at lower concentrations (0.39-6.25 μg/mL for resveratrol and 12.5-100.0 μg/mL for A2L) except at higher concentrations (12.5-25.0 μg/mL for resveratrol and 200-800 μg/mL for A2L) which are more pronounced in A2L-treated cells. Furthermore, the antioxidant status of HepG2 cells is not perturbed by resveratrol as compared with A2L. Assessment of 24-h post-treatment mitochondrial function shows that resveratrol is not mitotoxic as compared with A2L which exhibits mitotoxicity at its highest concentration.. Taken together, findings from this study showed that A2L possesses strong antiproliferative activity and its prospect in the management of hepatocellular carcinoma deserves further investigation.

Topics: Adenosine Triphosphate; Antineoplastic Agents, Phytogenic; Antioxidants; Apoptosis; Carcinoma, Hepatocellular; Caspases; Cell Proliferation; Combretaceae; Flavonoids; Hep G2 Cells; Humans; Liver Neoplasms; Mitochondria; Necrosis; Phenols; Phytotherapy; Plant Extracts; Plant Leaves; Resveratrol; Stilbenes

Vascular disrupting agents destroy established tumor vasculatures selectively, and have achieved encouraging antitumor activity in both pre-clinical and clinical trials. In the present study, we reported the vascular disruption and antitumor effects of CA-1H and its prodrug CA-1HP, oxazole bearing analogues of combretastatin A-4 (CA4). CA-1H was a tighter binder of tubulin than CA4 with the same binding site to chochcine and CA4, and inhibited tubulin polymerization both in cell free system and in human umbilical vein endothelial cells (HUVECs). Furthermore, CA-1H significantly disrupted the microtubulin skeleton in proliferating HUVECs rather than the quiescent ones, damaged the HUVECs-preformed tubes markedly, and lead to necrosis in tumor tissues in NCI-H1975 xenograft mice. Continuous administration for 19 days, CA-1HP could inhibit the NCI-H1975 xenograft tumor growth significantly without obvious weight loss and normal tissue damage, in addition, CA-1HP also inhibited the tumor growth in H22 hepatocellular carcinoma bearing mice; and combination CA-1HP with cisplatin showed more potent antitumor activity than used alone. Taken together, our present investigation suggested that CA-1H was a potential vascular disrupting agent for further development of antitumor drugs.

Topics: Animals; Binding Sites; Cell Line, Tumor; Cell Proliferation; Cell Shape; Cytoskeleton; Human Umbilical Vein Endothelial Cells; Humans; Liver Neoplasms; Mice, Inbred BALB C; Mice, Nude; Molecular Docking Simulation; Necrosis; Neovascularization, Pathologic; Neovascularization, Physiologic; Oxazoles; Polymerization; Stilbenes; Tubulin; Xenograft Model Antitumor Assays

Long non-coding RNAs (lncRNAs), a recently discovered class of non-coding genes, are transcribed throughout the genome. Emerging evidence suggests that lncRNAs may be involved in modulating various aspects of tumor biology, including regulating gene activity in response to external stimuli or DNA damage. No data are available regarding the expression of lncRNAs during genotoxic stress-induced apoptosis and/or necrosis in human glioma cells. In this study, we detected a change in the expression of specific candidate lncRNAs (neat1, GAS5, TUG1, BC200, Malat1, MEG3, MIR155HG, PAR5, and ST7OT1) during DNA damage-induced apoptosis in human glioma cell lines (U251 and U87) using doxorubicin (DOX) and resveratrol (RES). We also detected the expression pattern of these lncRNAs in human glioma cell lines under necrosis induced using an increased dose of DOX. Our results reveal that the lncRNA expression patterns are distinct between genotoxic stress-induced apoptosis and necrosis in human glioma cells. The sets of lncRNA expressed during genotoxic stress-induced apoptosis were DNA-damaging agent-specific. Generally, MEG3 and ST7OT1 are up-regulated in both cell lines under apoptosis induced using both agents. The induction of GAS5 is only clearly detected during DOX-induced apoptosis, whereas the up-regulation of neat1 and MIR155HG is only found during RES-induced apoptosis in both cell lines. However, TUG1, BC200 and MIR155HG are down regulated when necrosis is induced using a high dose of DOX in both cell lines. In conclusion, our findings suggest that the distinct regulation of lncRNAs may possibly involve in the process of cellular defense against genotoxic agents.

Topics: Antibiotics, Antineoplastic; Antineoplastic Agents, Phytogenic; Apoptosis; Cell Line, Tumor; DNA Damage; Doxorubicin; Glioma; Humans; Necrosis; Resveratrol; RNA, Long Noncoding; Stilbenes

Lung cancer is the leading cause of cancer-related death. About 80% of lung cancers are non-small cell lung cancers (NSCLC). Radiotherapy is widely used in treatment of NSCLC. However, the outcome of NSCLC remains unsatisfactory. In this study, a vascular disrupting agent (VDA) combretastatin-A4-phosphate (CA4P) was used to provide massive necrosis targets. (131)I labeled necrosis-avid agent protohypericin ((131)I-prohy) was explored for therapy of NSCLC using tumor necrosis targeted radiotherapy (TNTR). Gamma counting, autoradiography, fluorescence microscopy and histopathology were used for biodistribution analysis. Magnetic resonance imaging (MRI) was used to monitor tumor volume, ratios of necrosis and tumor doubling time (DT). The biodistribution data revealed 131I-prohy was delivered efficiently to tumors. Tracer uptake peaked at 24 h in necrotic tumor of (131)I-prohy with and without combined CA4P (3.87 ± 0.38 and 2.96 ± 0.34%ID/g). (131)I-prohy + CA4P enhanced the uptake of (131)I-prohy in necrotic tumor compared to (131)I-prohy alone. The TNTR combined with CA4P prolonged survival of tumor bearing mice relative to vehicle control group, CA4P control group and (131)I-prohy control group with median survival of 35, 20, 22 and 27 days respectively. In conclusion, TNTR appeared to be effective for the treatment of NSCLC.

Topics: Animals; Antineoplastic Agents; Autoradiography; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Chemoradiotherapy; Disease Models, Animal; Humans; Iodine Radioisotopes; Lung Neoplasms; Magnetic Resonance Imaging; Male; Mice, Inbred BALB C; Mice, Nude; Necrosis; Perylene; Radiography; Radiopharmaceuticals; Stilbenes; Tissue Distribution; Tumor Burden; Xenograft Model Antitumor Assays

Resveratrol derivatives bearing an O-linked mitochondria-targeting 4-triphenylphosphoniumbutyl group at either position 3 or position 4' are prooxidant and cytotoxic for cultured cells, selectively killing fast-growing cells when supplied in the low μM range. Resveratrol is essentially without effect under these experimental conditions, while the cytotoxicity of the mitochondriotropic derivatives increases if they are methylated on the remaining hydroxyls. Experiments with Bax(-/-)/Bak(-/-) cells and a pan-caspase inhibitor show that cell death is mostly of the necrotic type. Cytotoxicity is due to ROS produced upon accumulation of the compounds into mitochondria, and specifically to H2O2, since externally added membrane-permeant catalase largely prevents cell death while superoxide dismutase potentiates toxicity. The mitochondriotropic compounds cause ROS-independent depolarization of in situ mitochondria. Effectiveness is increased if resveratrol hydroxyls are acetylated or methylated; this excludes the involvement of autooxidation of the polyphenolic nucleus and a protonophoric cycle as the causes of ROS generation and of depolarization, respectively. Resveratrol-triphenylphosphonium conjugates may thus represent a new class of chemotherapeutic agents, redox-active "mitocans", whose mechanisms of action and in vivo activity are worthy of further investigation.

Topics: Animals; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; Cell Death; Cells, Cultured; Dose-Response Relationship, Drug; Gene Knockout Techniques; Hydrogen Peroxide; Mice; Mitochondria; Necrosis; Oxidants; Oxidation-Reduction; Reactive Oxygen Species; Resveratrol; Stilbenes

Glioblastomas, the most common form of primary brain tumors, are the fourth cause of death by cancer in adults. Increasing evidences suggest that glioblastoma resistance to existing radio- and chemotherapies rely on glioblastoma stem cells (GSCs). GSCs are endowed with a unique combination of stem-like properties alike to normal neural stem cells (NSCs), and of tumor initiating properties. The natural polyphenol resveratrol is known to exert opposite actions on neural cells according to their normal or cancerous status. Here, we used resveratrol to explore the molecular mechanisms differing between GSCs and NSCs. We observed a dual action of resveratrol on GSCs: resveratrol blocked GSC proliferation up to 150 μM and induced their necrosis at higher doses. On the opposite, resveratrol had no effect on NSC behavior. To determine the mechanisms underlying resveratrol effects, we focused our attention on the family of NAD-dependent deacetylases sirtuins (SIRT). A member of this family, SIRT1, has been repetitively shown to constitute a preferential resveratrol target, at least in normal cells. Western blot analysis showed that SIRT1 and SIRT3 were expressed by both GSCs and NSCs whereas SIRT2 expression was restricted to GSCs. Pharmacological blockade of SIRT2 activity or down-regulation of SIRT2 expression with siRNAs counteracted the inhibitory effect of resveratrol on cell proliferation. On the contrary, inhibition of SIRT2 activity or expression did not counteract GSC necrosis observed in presence of high doses of resveratrol. Our results highlight SIRT2 as a novel target for altering GSC properties.

Topics: Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Glioblastoma; Humans; Necrosis; Neoplastic Stem Cells; Resveratrol; RNA, Small Interfering; Sirtuin 2; Stilbenes; Structure-Activity Relationship; Tumor Cells, Cultured

Acute liver injury is manifested by different degree of hepatocyte necrosis and may recover via the process of hepatocyte regeneration once the injury is discontinued. Most of the liver injury is associating with inflammatory cytokines. Resveratrol (RSV) is a natural phytoalexin with powerful anti-inflammatory effects.. The effects of RSV on cellular factors mediating liver damage and regeneration in acute carbon tetrachloride (CCl4 ) liver injury were investigated.. RSV decreased alanine aminotransferase, aspartate aminotransferase, necrosis, and 4-hydroxynonenal in the CCl4 -injured liver. RSV decreased hepatocyte apoptosis by reducing caspase 8 and caspase 3 but not Bax and Bcl-xL. RSV reduced Kupffer cells recruitment, the expressions of tumor necrosis factor-α and interleukin-6, but not interleukin-10. RSV lowered the numbers of anti-5-bromon-2'-deoxyuridine and anti-Ki67-positive hepatocytes. Hepatic hepatocyte growth factor, c-Met and transforming growth factor-α expressions were reduced by RSV, while transforming growth factor-β1 and hepatic stellate cells activation were not changed. RSV reduced the injury-induced CXCL10 elevations in serum and liver in vivo. Besides, RSV inhibited CXCL10 release from CCl4 -injured hepatocytes in vitro. In contrast, recombinant CXCL10 improved the viability of CCl4 -injured hepatocytes.. RSV therapy can be beneficial for acute toxic liver injury. RSV reduced hepatocyte apoptosis but limited hepatocyte regeneration possibly through reducing the hepatomitogenic signaling and the release of CXCL10.

Topics: Alanine Transaminase; Aldehydes; Animals; Anti-Inflammatory Agents; Apoptosis; Aspartate Aminotransferases; Carbon Tetrachloride; Caspase 3; Caspase 8; Chemical and Drug Induced Liver Injury; Chemokine CXCL10; Cytokines; Hepatocytes; Inflammation Mediators; Liver; Liver Regeneration; Male; Mice; Mice, Inbred C57BL; Necrosis; Phytoalexins; Phytotherapy; Resveratrol; Sesquiterpenes; Stilbenes

Resveratrol is an antioxidant agent with multiple positive impacts on the body. It is known to have anti-diabetic, anti-inflammatory, anti-carcinogenic, and neuroprotective effects. The goal of this study is to demonstrate the antioxidant and anti-diabetic effects of resveratrol on flap survival in diabetic rats. Streptozotocin-induced diabetic Sprague-Dawley albino rats were treated with 10 mg/kg resveratrol following a flap surgery. Histological findings regarding polymorphonuclear leukocyte (PMNL) density, vascular proliferation, fibroblast density, and tissue necrosis were compared between resveratrol-treated and control rats. Significantly higher PMNL density was found in the control group (p = 0.005); while vascular proliferation and the fibroblast density were higher in the resveratrol group (p = 0.004 and p = 0.021, respectively). Collagen density was also higher in the resveratrol group and the difference has statistical significance (p = 0.024). Lymphocyte density was not significantly different between groups (p = 0.061). When the necrosis in the distal areas was evaluated histologically, 20% of the resveratrol group had epidermal tissue necrosis, thus 90% of the control group had epidermal or full-layer necrosis. Resveratrol improved flap survival significantly in diabetic rats. Therefore, diabetic patients requiring complex reconstructive procedures may benefit from resveratrol; so, clinical trials are required to support this study.

Topics: Animals; Antioxidants; Diabetes Mellitus, Experimental; Hypoglycemic Agents; Ischemia; Necrosis; Oxidative Stress; Rats, Sprague-Dawley; Resveratrol; Stilbenes; Surgical Flaps; Wound Healing

Human mesenchymal stem cell (hMSC) research has grown exponentially in the last decade. The ability to process and preserve these cells is vital to their use in stem cell therapy. As such, understanding the complex, molecular-based stress responses associated with biopreservation is necessary to improve outcomes and maintain the unique stem cell properties specific to hMSC. In this study hMSC were exposed to cold storage (4°C) for varying intervals in three different media. The addition of resveratrol or salubrinal was studied to determine if either could improve cell tolerance to cold. A rapid elevation in apoptosis at 1h post-storage as well as increased levels of necrosis through the 24h of recovery was noted in samples. The addition of resveratrol resulted in significant improvements to hMSC survival while the addition of salubrinal revealed a differential response based on the media utilized. Decreases in both apoptosis and necrosis together with decreased cell stress/death signaling protein levels were observed following modulation. Further, ER stress and subsequent unfolded protein response (UPR) stress pathway activation was implicated in response to hMSC hypothermic storage. This study is an important first step in understanding hMSC stress responses to cold exposure and demonstrates the impact of targeted molecular modulation of specific stress pathways on cold tolerance thereby yielding improved outcomes. Continued research is necessary to further elucidate the molecular mechanisms involved in hypothermic-induced hMSC cell death. This study has demonstrated the potential for improving hMSC processing and storage through targeting select cell stress pathways.

Topics: Apoptosis; Blotting, Western; Cell Survival; Cinnamates; Cryopreservation; Cryoprotective Agents; Flow Cytometry; Humans; Mesenchymal Stem Cells; Necrosis; Osmoregulation; Resveratrol; Stilbenes; Stress, Physiological; Thiourea

Arsenic trioxide (As2O3), which used as an effective agent in the treatment of leukaemia and other solid tumors, is largely limited by its toxicity. QT prolongation, torsades de pointes and sudden heart death have been implicated in the cardiotoxicity of As2O3. The present study was designed to explore whether the combination of As2O3 and resveratrol could generate a more powerful anti-cancer effect both in vitro and in vivo.. MTT assay was performed to assess the proliferation of Hela, MCF-7 and NB4 cells. Isobolographic analysis was used to evaluate combination index values from cell viability data. The apoptosis and the cellular reactive oxygen species (ROS) level were assessed by fluorescent microscopy and flow cytometry separately in vitro. The effect of As2O3, alone and in combination with resveratrol on Hela tumor growth in an orthotopic nude mouse model was also investigated. The tumor volume and the immunohistochemical analysis of CD31, CD34 and VEGF were determined.. Resveratrol dramatically enhanced the anti-cancer effect induced by As2O3 in vitro. In addition, isobolographic analysis further demonstrated that As2O3 and resveratrol generated a synergistic action. More apoptosis and ROS generation were observed in the combination treatment group. Similar synergistic effects were found in nude mice in vivo. The combination of As2O3 and resveratrol dramatically suppressed both tumor growth and angiogenesis in nude mice.. Combining As2O3 with resveratrol would be a novel strategy to treat cancer in clinical practice.

Topics: Animals; Antineoplastic Agents; Apoptosis; Arsenic Trioxide; Arsenicals; Cell Line, Tumor; Cell Proliferation; Cell Survival; Disease Models, Animal; Drug Synergism; Humans; Male; Mice; Necrosis; Neovascularization, Pathologic; Oxides; Reactive Oxygen Species; Resveratrol; Stilbenes; Tumor Burden; Xenograft Model Antitumor Assays

Residual cancer cells and subsequent tumor relapse is an obstacle for curative cancer treatment. Tumor necrosis therapy (TNT) has recently been developed to cause residual tumor regression or destruction. Here, we exploited the avidity of the sennidin A (SA) tracer and radioiodinated SA (¹³¹I-SA) to necrotic tumors in order to further empower TNT. We showed high uptake and prolonged retention of SA in necrotic tumors and a quick clearance in other non-targeted tissues including the liver. On SPECT-CT images, tumor mass appeared persistently as a hotspot. Based on the prominent targetability of ¹³¹I-SA to the tumor necrosis, we designed a combinational theragnostic modality. The vascular disrupting agent (VDA) combretastatin A4 phosphate (CA4P) was used to cause massive tumor necrosis, which formed the target of ¹³¹I-SA that subsequently killed the residual tumor cells by cross-fire irradiation of beta particles. Consequently, ¹³¹I-SA combined with CA4P significantly inhibited tumor growth, extended tumor doubling time and prolonged mean animal survival. In conclusion, ¹³¹I-SA in combination with necrosis inducing drugs/therapies may generate synergetic tumoricidal effects on solid malignancies by means of primary debulking and secondary cleansing process.

Topics: Animals; Anthracenes; Antineoplastic Combined Chemotherapy Protocols; Autoradiography; Disease Models, Animal; Iodine Radioisotopes; Magnetic Resonance Imaging; Mice; Necrosis; Neoplasms, Experimental; Positron-Emission Tomography; Rats; Rats, Sprague-Dawley; Stilbenes

Pinosylvin is a known functional compound of the Pinus species. Pinosylvin at low concentrations (∼ pmol/L) was reported to promote cell proliferation in endothelial cells. However, this study found that pinosylvin at a high concentration (100 μmol/L) induces cell death in bovine aortic endothelial cells. Therefore, we examined how pinosylvin was associated with apoptosis, autophagy, and necrosis. Pinosylvin at a high concentration appeared to promote caspase-3 activation, nuclear condensation, and the "flip-flop" of phosphatidylserine, indicating that pinosylvin induces apoptosis. However, based on flow cytometry data obtained from double-staining with annexin V and propidium iodide, pinosylvin was shown to inhibit necrosis, a postapoptotic process. Pinosylvin induced LC3 conversion from LC3-I to LC3-II and p62 degradation, which are important indicators of autophagy. In addition, AMP-activated protein kinase (AMPK) appeared to be activated by pinosylvin, and an AMPK inhibitor was markedly shown to reduce the LC3 conversion. The inhibitory effect of an AMPK inhibitor was reversed by pinosylvin. These results suggest that pinosylvin induces autophagy via AMPK activation. Further, necrosis was found to be promoted by an autophagy inhibitor and then restored by pinosylvin, while the caspase-3 inhibitor had no effect on necrosis. These findings indicate that pinosylvin-induced autophagy blocks necrotic progress in endothelial cells.

Topics: AMP-Activated Protein Kinases; Animals; Aorta, Thoracic; Apoptosis; Apoptosis Regulatory Proteins; Autophagy; Cattle; Cells, Cultured; Dose-Response Relationship, Drug; Endothelial Cells; Necrosis; Pinus; Stilbenes

The public interest steadily increases in the biological adverse effects caused by components released from resin-based dental restorations.. In this study, the cytotoxicity and the genotoxicity were investigated of following released components from dental resin restorations in human gingival fibroblasts (HGF): tetraethyleneglycol dimethacrylate (TEEGDMA), neopentylglycol dimethacrylate (Neopen), diphenyliodoniumchloride (DPIC), triphenyl-stibane (TPSB) and triphenylphosphane (TPP).. XTT based cell viability assay was used for cytotoxicity screening of substances. γ-H2AX assay was used for genotoxicity screening. In the γ-H2AX assay, HGFs were exposed to the substances for 6h. Induced foci represent double DNA strand breaks (DSBs), which can induce ATM-dependent phosphorylation of the histone H2AX. Cell death effects (apoptosis and necrosis), induced by the substances were visually tested by the same investigator using the fluorescent microscope.. All tested substances induced a dose-dependent loss of viability in HGFs. Following toxicity ranking among the substances at EC50-concentration were found in the XTT assay (mM, mean±SEM; n=5): DPIC>Neopen>TPSB>TPP>TEEGDMA. DSB-foci per HGF-cell were obtained, when HGFs were exposed to the EC50-concentration of each substance in the following order (mean±SEM; n=3): DPIC>Neopen>TPSB>TPP>TEEGDMA. Multi-foci cells (cells that contain more than 40 foci each) in 80 HGF-cells at EC50-concentration of each substance were found as follow (mean±SEM; n=3): DPIC>Neopen>TPP>TPSB>TEEGDMA. Cell apoptosis contained in each substance at EC50-concentration in the following order (mean±SEM; n=3): DPIC>Neopen>TPSB>TPP >TEEGDMA. Cell necrosis contained in each substance at EC50-concentration in the following order (mean±SEM; n=3): DPIC>Neopen>TPSB>TPP>TEEGDMA.. Leached components from dental resin restorations can induce DNA DSBs and cell death effects in HGFs.

Topics: Apoptosis; Biphenyl Compounds; Cell Culture Techniques; Cell Line; Cell Survival; Composite Resins; Dental Materials; DNA Breaks, Double-Stranded; Dose-Response Relationship, Drug; Fibroblasts; Gingiva; Histones; Humans; Indicators and Reagents; Materials Testing; Methacrylates; Microscopy, Fluorescence; Mutagens; Necrosis; Onium Compounds; Organophosphorus Compounds; Polyethylene Glycols; Polymethacrylic Acids; Stilbenes; Tetrazolium Salts

In the present study, the effect of a novel derivative of riccardin D (RD-N) against cancer cell lines was investigated in vitro and in vivo. We found that RD-N accumulated in the lysosomes associated with lysosomal swelling. As a result, the destabilized lysosomes induced cathepsins to release from the lysosomes into the cytosol and induced cell death which displayed features characteristic to both apoptosis and necrosis. In vivo tumor xenograft model indicated treatment of RD-N significantly reduced size and weight of the tumor compared with vehicles. These findings suggest RD-N could be a promising candidate for treatment of cancer.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cytoskeletal Proteins; Cytoskeleton; Etoposide; Humans; Inhibitory Concentration 50; Lysosomes; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Necrosis; Phenyl Ethers; Stilbenes; Tumor Burden; Xenograft Model Antitumor Assays

We sought to compare the therapeutic efficacy between two vascular-disrupting agents, combretastatin A4 phosphate (CA4P) and ZD6126, at a clinically relevant dose on tumor models with magnetic resonance imaging (MRI). Thirty rats with liver rhabdomyosarcoma were randomized into CA4P (10 mg/kg), ZD6126 (10 mg/kg), and control group (n=10 for each group). Multiparametric MRI biomarkers including tumor volume, enhancement ratio, necrosis ratio, apparent diffusion coefficient (ADC), and K (volume transfer constant) derived from T2-weighted, T1-weighted, contrast-enhanced T1-weighted, and diffusion-weighted imaging, and dynamic contrast-enhanced MRI were compared at pretreatment, 1 h, 6 h, 24 h, 48 h, and 120 h posttreatment; they were validated using ex-vivo techniques. Relative to rapidly growing tumors without necrosis in control rats, tumors grew slower in the CA4P group compared with the ZD6126 group with a higher necrosis ratio at 120 h (P<0.05), as proven by histopathology. In the CA4P group, K decreased from 1 h until 6 h, and partially recovered at 120 h. In the ZD6126 group, the reduced K at 1 h began to rebound from 6 h and exceeded the baseline value at 120 h (P<0.05), parallel to evolving enhancement ratios (P<0.05). ADC revealed more necrotic tumors with CA4P versus ZD6126 at 120 h (P<0.05). The different tumor responses were confirmed by ex-vivo microangiography and histopathology. CA4P was more effective than ZD6126 in impairing blood supply, inducing necrosis, and delaying growth in rat liver tumors at a clinically relevant dose. A single dose of vascular-disrupting agent was insufficient to destroy the tumor. The multiparametric MRI biomarkers enabled in-vivo noninvasive comparison of therapeutic efficacy between CA4P and ZD6126.

Topics: Animals; Antineoplastic Agents, Phytogenic; Biomarkers, Tumor; Contrast Media; Drug Screening Assays, Antitumor; Injections, Intravenous; Liver Neoplasms, Experimental; Magnetic Resonance Imaging; Male; Microvessels; Necrosis; Organophosphorus Compounds; Rats; Rats, Inbred Strains; Rhabdomyosarcoma; Stilbenes; Tumor Burden

The phenolic phytoalexin resveratrol is well known for its health-promoting and anticancer properties. Its potential benefits are, however, limited due to its low bioavailability. Pterostilbene, a natural dimethoxylated analog of resveratrol, presents higher anticancer activity than resveratrol. The mechanisms by which this polyphenol acts against cancer cells are, however, unclear. Here, we show that pterostilbene effectively inhibits cancer cell growth and stimulates apoptosis and autophagosome accumulation in cancer cells of various origins. However, these mechanisms are not determinant in cell demise. Pterostilbene promotes cancer cell death via a mechanism involving lysosomal membrane permeabilization. Different grades of susceptibility were observed among the different cancer cells depending on their lysosomal heat shock protein 70 (HSP70) content, a known stabilizer of lysosomal membranes. A375 melanoma and A549 lung cancer cells with low levels of HSP70 showed high susceptibility to pterostilbene, whereas HT29 colon and MCF7 breast cancer cells with higher levels of HSP70 were more resistant. Inhibition of HSP70 expression increased susceptibility of HT29 colon and MCF7 breast cancer cells to pterostilbene. Our data indicate that lysosomal membrane permeabilization is the main cell death pathway triggered by pterostilbene.

Topics: Antineoplastic Agents; Apoptosis; Autophagy; Caspases; Cell Death; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Flow Cytometry; HSP70 Heat-Shock Proteins; Humans; Inhibitory Concentration 50; L-Lactate Dehydrogenase; Lysosomes; Microscopy, Confocal; Necrosis; Neoplasms; Permeability; Phagosomes; Resveratrol; Stilbenes

Unlike normal blood vessels, the unique characteristics of an expanding, disorganized and leaky tumor vascular network can be targeted for therapeutic gain by vascular disrupting agents (VDAs), which promote rapid and selective collapse of tumor vessels, causing extensive secondary cancer cell death. A hallmark observation following VDA treatment is the survival of neoplastic cells at the tumor periphery. However, comparative studies with the second generation tubulin-binding VDA OXi4503 indicate that the viable rim of tumor tissue remaining following treatment with this agent is significantly smaller than that seen for the lead VDA, combretastatin. OXi4503 is the cis-isomer of CA1P and it has been speculated that this agent's increased antitumor efficacy may be due to its reported metabolism to orthoquinone intermediates leading to the formation of cytotoxic free radicals. To examine this possibility in situ, KHT sarcoma-bearing mice were treated with either the cis- or trans-isomer of CA1P. Since both isomers can form quinone intermediates but only the cis-isomer binds tubulin, such a comparison allows the effects of vascular collapse to be evaluated independently from those caused by the reactive hydroxyl groups. The results showed that the cis-isomer (OXi4503) significantly impaired tumor blood flow leading to secondary tumor cell death and >95% tumor necrosis 24h post drug exposure. Treatment with the trans-isomer had no effect on these parameters. However, the combination of the trans-isomer with combretastatin increased the antitumor efficacy of the latter agent to near that of OXi4503. These findings indicate that while the predominant in vivo effect of OXi4503 is clearly due to microtubule collapse and vascular shut-down, the formation of toxic free radicals likely contributes to its enhanced potency.

Topics: Animals; Antineoplastic Agents; Blood Vessels; Cell Survival; Cells, Cultured; Diphosphates; Endothelial Cells; Female; Free Radicals; Humans; Magnetic Resonance Imaging; Mice; Mice, Inbred C3H; Microtubules; Necrosis; Neovascularization, Physiologic; Regional Blood Flow; Sarcoma, Experimental; Stilbenes; Tubulin Modulators; Tumor Stem Cell Assay

Leaves of different Vitis vinifera L. cultivars, susceptible or resistant to downy mildew, Chasselas, Solaris, IRAC 2091 (cvs. Gamaret x Bronner) and Muscadinia rotundifolia were inoculated with Plasmopara viticola. Samples were then examined by scanning and transmission electron microscopy, by light microscopy and for their ability to synthesise stilbenes. These phytoalexins were strictly analysed at infection sites. In the susceptible Chasselas, P. viticola colonises, at 72h post-infection (hpi), all of the spongy mesophyll with functional haustoria and produces mainly the non toxic piceide. No necrotic zone was observed on Chasselas leaves. The ultrastructural response to downy mildew infection is different in each of the other three resistant grape cultivars. In Solaris, where leaf necrosis are rapidly induced, the infection is restricted to the upper part of the loose spongy mesophyll, and associated with a rapid cell wall disruption and the dispersion of cytoplasmic content along with the production of viniferins. In IRAC 2091, leaf necrosis are quite similar to those observed on Solaris but the infected plant cell, as well as the haustoria, show high electron dense cellular particles without any recognisable organelles, probably related to the effect of the toxic compound pterostilbene, which is synthesised in this grape cultivar. In M. rotundifolia leaf necrosis are much more scarce and smaller than in other cultivars, but pathogen and plant cells are both strongly affected, with concomitant expulsion of cytoplasmic materials through the stomata after P. viticola penetration. In this cultivar, the concentration of all identified stilbenes exceeds 1×10³ μmol mg(-1) FW. The critical role of stilbenes in the resistance of Vitis spp. is discussed.

Topics: Cytoplasm; Necrosis; Oomycetes; Phytoalexins; Plant Diseases; Plant Immunity; Plant Leaves; Plant Stomata; Sesquiterpenes; Species Specificity; Stilbenes; Vitis

To develop a combination treatment consisting of combretastatin A-4-phosphate (CA4P) with radiation based on tumor oxygenation status.. In vivo near-infrared spectroscopy (NIRS) and diffusion-weighted (DW) magnetic resonance imaging (MRI) were applied to noninvasively monitor changes in tumor blood oxygenation and necrosis induced by CA4P (30 mg/kg) in rat mammary 13762NF adenocarcinoma, and the evidence was used to optimize combinations of CA4P and radiation treatment (a single dose of 5 Gy).. NIRS showed decreasing concentrations of tumor vascular oxyhemoglobin and total hemoglobin during the first 2 h after CA4P treatment, indicating significant reductions in tumor blood oxygenation and perfusion levels (p < 0.001). Twenty-four hours later, in response to oxygen inhalation, significant recovery was observed in tumor vascular and tissue oxygenation according to NIRS and pimonidazole staining results, respectively (p < 0.05). DW MRI revealed significantly increased water diffusion in tumors measured by apparent diffusion coefficient at 24 h (p < 0.05), suggesting that CA4P-induced central necrosis. In concordance with the observed tumor oxygen dynamics, we found that treatment efficacy depended on the timing of the combined therapy. The most significant delay in tumor growth was seen in the group of tumors treated with radiation while the rats breathed oxygen 24 h after CA4P administration.. Noninvasive evaluation of tumor oxygen dynamics allowed us to rationally enhance the response of syngeneic rat breast tumors to combined treatment of CA4P with radiation.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Hypoxia; Combined Modality Therapy; Diffusion Magnetic Resonance Imaging; Female; Hemoglobins; Mammary Neoplasms, Experimental; Necrosis; Oxygen; Oxyhemoglobins; Rats; Rats, Inbred F344; Spectroscopy, Near-Infrared; Stilbenes; Time Factors

Vascular-disrupting agents (VDAs) such as combretastatin A4 phosphate (CA4P) selectively disrupt blood vessels in tumors and induce tumor necrosis. However, tumors rapidly repopulate after treatment with such compounds. Here, we show that CA4P-induced vessel narrowing, hypoxia, and hemorrhagic necrosis in murine mammary tumors were accompanied by elevated tumor levels of the chemokine CXCL12 and infiltration by proangiogenic TIE2-expressing macrophages (TEMs). Inhibiting TEM recruitment to CA4P-treated tumors either by interfering pharmacologically with the CXCL12/CXCR4 axis or by genetically depleting TEMs in tumor-bearing mice markedly increased the efficacy of CA4P treatment. These data suggest that TEMs limit VDA-induced tumor injury and represent a potential target for improving the clinical efficacy of VDA-based therapies.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Separation; Chemokine CXCL12; Female; Flow Cytometry; Macrophages; Mammary Neoplasms, Animal; Mice; Mice, Transgenic; Necrosis; Neoplasm Transplantation; Receptor Protein-Tyrosine Kinases; Receptor, TIE-2; Receptors, CXCR4; Stilbenes

There has been a recently increase in the development of novel stilbene-based compounds with in vitro anti-inflamatory properties. For this study, we synthesized and evaluated the anti-inflammatory properties of 2 fluorinated stilbenes on carbon tetrachloride (CCl₄)-induced acute liver damage. To achieve this, CCl₄ (4 g·kg(-1), per os) was administered to male Wistar rats, followed by either 2-fluoro-4'-methoxystilbene (FME) or 2,3-difluoro-4'-methoxystilbene (DFME) (10 mg·kg(-1), per os). We found that although both of the latter compounds prevented cholestatic damage (γ-glutamyl transpeptidase activity), only DFME showed partial but consistent results in the prevention of necrosis, as assessed by both alanine aminotransferase activity and histological analysis. Since inflammatory responses are mediated by cytokines, mainly tumour necrosis factor α (TNF-α), we used the Western blot technique to determine the action of FME and DFME on the expression level of this cytokine. The observed increase in the level of TNF-α caused by CCl₄ administration was only prevented by treatment with DFME, in agreement with our biochemical findings. This result was confirmed by measuring interleukin-6 (IL-6) levels, since the expression of this protein depends on the level of TNF-α. In this case, DFME completely blocked the CCl₄-induced increase of IL-6. Our results suggest that DFME possesses greater anti-inflammatory properties in vivo than FME. DFME constitutes a possible therapeutic agent for liver disease and could serve as a template for structure optimization.

Topics: Animals; Anti-Inflammatory Agents; Carbon Tetrachloride; Chemical and Drug Induced Liver Injury; Cholestasis; Disease Models, Animal; Drug Evaluation, Preclinical; Humans; Hydrocarbons, Fluorinated; Interleukin-6; Male; Necrosis; Rats; Rats, Wistar; Stilbenes; Tumor Necrosis Factor-alpha

To investigate the role of reactive oxygen species (ROS) induced by butyrate in tumor cells, we compared HT29R, an HT29-derived human colon cancer cell line refractory to butyrate-induced cell differentiation but highly sensitive to cell death, with the differentiation-positive HT29-12 and HT29-21 cell lines (exhibiting low sensitivity to butyrate-induced cell death), with respect to levels of butyrate-induced free radicals (FRs), ROS, and H(2)O(2). Dose-dependent increase of FRs (as determined by electron spin resonance spectroscopy) and ROS (dichlorofluorescein assay) was induced in HT29R, but not in HT29-12 and HT29-21 cells, where, in contrast to HT29R, a dose-dependent increase of H(2)O(2) release (phenol red assay) was induced by butyrate. The mode of butyrate-induced cell death in HT29R cells was of a mixed type with necrosis predominating, which, however, switched to apoptosis as the major type of cell death in the presence of the drugs 1,5-dihydroxyisoquinoline, resveratrol, or cyclosporine A. The results suggest that FRs and ROS induced by butyrate in HT29R cells are products of cell death, while H(2)O(2) induced in HT29-12 and HT29-21 cells is functionally related to cell differentiation.

Topics: Antioxidants; Apoptosis; Butyrates; Cell Adhesion; Cell Death; Cell Differentiation; Cell Division; Cyclosporine; Dose-Response Relationship, Drug; Electron Spin Resonance Spectroscopy; Free Radicals; HT29 Cells; Humans; Hydrogen Peroxide; Immunosuppressive Agents; In Situ Nick-End Labeling; Isoquinolines; Necrosis; Reactive Oxygen Species; Resveratrol; Stilbenes

The potential for colloidal carriers to increase drug bioavailability has spurred a renewed interest in their uptake mechanisms and movement within cells. Solid lipid nanoparticles (SLN) were used as a carrier for a promising chemopreventive drug, resveratrol (RSV). The effects of SLN, empty or loaded with RSV (SLN-RSV), on the internalization, growth, morphology, metabolic activity and genetic material of keratinocytes were compared to those of RSV in solution. Fluorescence images clearly showed that SLN with a size below 180 nm move promptly through the cell membrane, distribute throughout the cytosol, move successively among different cellular levels and localize in the perinuclear region without inducing cytotoxicity. RSV solubility, stability and intracellular delivery were all increased by loading into SLN. The release profile of RSV showed a biphasic pattern, reflecting its distribution in SLN. RSV in solution was slightly cytotoxic. That was prevented by loading it into solid lipid nanoparticles, which preserved cell morphology. The cytostatic effect of SLN-RSV was much more expressed than that of RSV in solution. Delivery of RSV by SLN contributes to effectiveness of RSV on decreasing cell proliferation, with potential benefits for prevention of skin cancer.

Topics: Anticarcinogenic Agents; Biological Availability; Cell Cycle; Cell Line, Transformed; Cell Nucleus; Cell Proliferation; Cell Shape; Cell Size; Delayed-Action Preparations; Drug Carriers; Humans; Hydrophobic and Hydrophilic Interactions; Intracellular Space; Keratinocytes; Lecithins; Lipids; Metabolism; Microscopy, Fluorescence; Nanoparticles; Necrosis; Particle Size; Poloxamer; Resveratrol; Static Electricity; Stilbenes

To investigate potential inhibitory effects of three polyphenolic agents, epigallocatechin gallate (EGCG; from green tea), resveratrol (from red wine), and curcumin (from turmeric), on the proliferation of human retinal pigment epithelial (RPE) cells and to elucidate unwanted effects.. ARPE19 cells and primary human RPE cells were cultured in the presence of various concentrations of EGCG, resveratrol, or curcumin, and compared with controls. The number of viable cells was determined after 24, 48, and 72 hr by flow cytometrical enumeration. Furthermore, cell division was measured by dye dilution assay using carboxyfluorescein succinimidyl ester (CFSE), cell death by Hoechst 33258 staining, and apoptosis by staining for active caspase 3/7 and 8.. The three drugs inhibited the increase of RPE cell numbers at all time points, with resveratrol being the most efficient and curcumin being the least efficient. EGCG inhibited cell proliferation with intermediate efficiency, and showed little induction of cell death. Resveratrol almost completely suppressed cell proliferation, and induced RPE cell necrosis and caspase 3/7- and caspase 8-dependent apoptosis. Curcumin inhibited RPE cell increase exclusively by inducing caspase 3/7-dependent but caspase 8-independent cell death and necrosis.. All three polyphenols tested reduced the absolute number of cells, but had different effects on cell proliferation, apoptosis, and necrosis. Resveratrol was most potent and EGCG induced the least cell death. These polyphenols may aid treatment of proliferative vitreoretinopathy (PVR).

Topics: Antioxidants; Apoptosis; Caspases; Catechin; Cell Division; Cell Proliferation; Cell Survival; Cells, Cultured; Curcumin; Flow Cytometry; Humans; Necrosis; Resveratrol; Retinal Pigment Epithelium; Stilbenes

The effects of the tubulin-binding vascular-disrupting agents (VDAs), combretastatin A4 phosphate (CA4P), OXi4503/CA1P and OXi8007, in subcutaneous mouse models of the Ewing's sarcoma family of tumours (ESFTs) have been investigated alone and in combination with doxorubicin. Delay in subcutaneous tumour growth was observed following treatment of mice with multiple doses of OXi4503/CA1P but not with CA4P or OXi8007. A single dose of OXi4503/CA1P caused complete shutdown of vasculature by 24h and extensive haemorrhagic necrosis by 48h. However, a viable rim of proliferating cells remained, which repopulated the tumour within 10 days following the withdrawal of treatment. Combined treatment with doxorubicin 1h prior to administration of OXi4503/CA1P enhanced the effects of OXi4503/CA1P causing a synergistic delay in tumour growth (p<0.001). This study demonstrates that OXi4503/CA1P is a potent VDA in ESFT and in combination with conventional cytotoxic agents represents a promising treatment strategy for this tumour group.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Bibenzyls; Bone Neoplasms; Cell Proliferation; Diphosphates; Disease Models, Animal; Doxorubicin; Drug Evaluation, Preclinical; Mice; Mice, Nude; Necrosis; Neoplasm Transplantation; Neovascularization, Pathologic; Sarcoma, Ewing; Stilbenes

To determine the feasibility of in vivo diffusion-weighted imaging (DWI) to distinguish between normal liver, viable tumor and necrosis compared to postmortem DWI in a rat model with vascular-targeting treatment.. Fifteen rats with liver implantation of 30 rhabdomyosarcomas were treated with combretastatin A-4-phosphate (CA4P) at 10 mg/kg. Two days after treatment, T2-weighted imaging, precontrast T1-weighted imaging, postcontrast T1-weighted imaging, and DWI were performed in vivo and postmortem with a 1.5T scanner. Apparent diffusion coefficients (ADCs) calculated from DWIs with b values of 0, 50, and 100 seconds/mm2 (ADClow), 500, 750, and 1000 seconds/mm2 (ADChigh), 0, 500, and 1000 seconds/mm2 (ADC3b), and 0-1000 seconds/mm2 (ADC10b) for tumor, liver, therapeutic necrosis, and phantoms were compared and validated with ex vivo microangiographic and histopathologic findings.. Except ADClow between tumor and necrosis, in vivo ADCs successfully differentiated liver, viable tumor, and necrosis (P<0.05). Compared to in vivo outcomes, postmortem ADCs significantly dropped in tumor and liver (P<0.05) except ADChigh of tumor, but not in necrosis and phantoms. Compared to ADClow, ADChigh was less affected by vital status.. Advantageous over postmortem DWI, in vivo DWI provides a noninvasive easy-performing tool for distinguishing between liver, viable tumor, and necrosis. ADClow and ADChigh better reflect tissue perfusion and water diffusion, respectively.

Topics: Animals; Antineoplastic Agents, Phytogenic; Contrast Media; Diagnosis; Diagnosis, Differential; Diffusion Magnetic Resonance Imaging; Disease Models, Animal; Feasibility Studies; Image Enhancement; Image Processing, Computer-Assisted; Liver; Liver Neoplasms, Experimental; Male; Necrosis; Phantoms, Imaging; Rats; Rats, Wistar; Rhabdomyosarcoma; Stilbenes

Vascular disrupting agents preferentially target the established but abnormal tumor vasculature, resulting in extensive intratumoral hypoxia and cell death. However, a rim of viable tumor tissue remains from which angiogenesis-dependent regrowth can occur, in part through the mobilization and tumor colonization of circulating endothelial progenitor cells (CEP). Cotreatment with an agent that blocks CEPs, such as a vascular endothelial growth factor pathway-targeting biological antiangiogenic drug, results in enhanced antitumor efficacy. We asked whether an alternative therapeutic modality, low-dose metronomic chemotherapy, could achieve the same result given its CEP-targeting effects. We studied the combination of the vascular disrupting agent OXi4503 with daily administration of CEP-inhibiting, low-dose metronomic cyclophosphamide to treat primary orthotopic tumors with the use of the 231/LM2-4 breast cancer cell line and MeWo melanoma cell line. In addition, CEP mobilization and various tumor characteristics were assessed. We found that daily p.o. low-dose metronomic cyclophosphamide was capable of preventing the CEP spike and tumor colonization induced by OXi4503. This was associated with a decrease in the tumor rim and marked suppression of primary 231/LM2-4 growth in nude as well as severe combined immunodeficient mice. Similar results were found in MeWo-bearing nude mice. The delay in tumor growth was accompanied by significant decreases in microvessel density, perfusion, and proliferation, and a significant increase in tumor cell apoptosis. No overt toxicity was observed. The combination of OXi4503 and metronomic chemotherapy results in prolonged tumor control, thereby expanding the list of therapeutic agents that can be successfully integrated with metronomic low-dose chemotherapy.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Bone Marrow Cells; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Cyclophosphamide; Diphosphates; Dose-Response Relationship, Drug; Endothelial Cells; Green Fluorescent Proteins; Humans; Mice; Microvessels; Necrosis; Neovascularization, Pathologic; Stem Cells; Stilbenes; Xenograft Model Antitumor Assays

Oxidative stress is recognized as an important factor in the development of liver pathologies. The reactive oxygen species endogenously generated or as a consequence of xenobiotic metabolism are eliminated by enzymatic and nonenzymatic cellular systems. Besides endogen defences, the antioxidant consumption in the diet has an important role in the protection against the development of diseases product of oxidative damage. Resveratrol is a naturally occurring compound which is part of the human diet. This molecule has been shown to have many biological properties, including antioxidant activity. We decided to test if resveratrol could protect primary hepatocytes in culture from oxidative stress damage and if so, to determine if this compound affects the cellular detoxifying systems and their regulation through the Nrf2 transcription factor that regulates the expression of antioxidant and phase II detoxifying enzymes. Cell death by necrosis was detected by measuring the activity of lactate dehydrogenase liberated to the medium. The activities of antioxidant and phase II enzymes were measured using previously described methods. Activation of the Nrf2 transcription factor was studied by confocal microscopy and the Nrf2 and its coding mRNA levels were determined by western blot and quantitative PCR respectively. Resveratrol pre-treatment effectively protected hepatocytes in culture exposed to oxidative stress, increasing the activities of catalase, superoxide dismutase, glutathione peroxidase, NADPH quinone oxidoreductase and glutathione-S-transferase. Resveratrol increases the level of Nrf2 and induces its translocation to the nucleus. Also, it increases the concentration of the coding mRNA for Nrf2. In this work we show that resveratrol could be a useful drug for the protection of liver cells from oxidative stress induced damage.

Topics: Animals; Antioxidants; Blotting, Western; Cells, Cultured; Enzymes; Gene Expression Regulation; Hepatocytes; Male; Necrosis; NF-E2-Related Factor 2; Oxidative Stress; Polymerase Chain Reaction; Rats; Rats, Sprague-Dawley; Resveratrol; RNA, Messenger; Stilbenes

Reactive oxygen species can be important mediators of damage to cell molecules and structures. Besides the endogen antioxidant defences, the antioxidant intake in the diet has an important role in the protection against the development of diseases produced by oxidative damage. Resveratrol is a naturally occurring compound present in many plants some of which are part of the human diet. This molecule has been thoroughly investigated because of its antioxidant and anticarcinogenic properties among others. We investigated whether resveratrol could provide protective antioxidant action in primary rat hepatocyte cultures. Primary rat hepatocytes cultures were exposed to 300 microM tert-butyl hydroperoxide; 25, 50 or 75 microM resveratrol or to 300 microM tert-butyl hydroperoxide plus 25, 50 or 75 microM resveratrol for different time periods. Necrosis was evaluated by lactate dehydrogenase liberation to the medium. Apoptosis was evaluated by caspase 3 activity measurement. Changes in cellular morphology after the different treatments were recorded using bright field microscopy. Inhibition of the reactive oxygen species by resveratrol was studied by confocal microscopy and spectrofluorimetrically. Resveratrol inhibited necrosis induced by tert-butyl hydroperoxide. No apoptosis was observed in any treatment. It also was effective in eliminating reactive oxygen species. At 75 microM, the highest concentration tested, resveratrol became slightly cytotoxic. Our results show that resveratrol protects primary rat hepatocytes in culture from oxidative stress induced cell death. These results suggest that resveratrol could enhance the antioxidant status of hepatic cells.

Topics: Animals; Antioxidants; Apoptosis; Cell Survival; Cells, Cultured; Dose-Response Relationship, Drug; Hepatocytes; Male; Necrosis; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Resveratrol; Stilbenes

Oxi4503 is a potent vascular targeting agent belonging to the family of combretastatins. These agents produce an acute reduction in tumor blood flow leading to tumor necrosis. Despite evidence of its efficacy in certain malignancies, the effect on colorectal liver metastases remains largely unknown. This study investigates the effect of Oxi4503 on colorectal liver metastases in a murine model.. The effect of a single dose of Oxi4503 on established tumors in a murine model of colorectal liver metastases was assessed following administration of 1-50 mg/kg Oxi4503. In addition, the effects of continuous, daily and intermittent dosing (1-5 mg/kg) on tumor necrosis and growth were studied by quantitative histological and stereological analysis. The effect of multiple dosing on long-term survival was also assessed using the Kaplan-Meier analysis. The microvascular effects of therapy were studied by scanning electron microscopy of microvascular resin casts.. A single dose of 5 or 50 mg/kg of Oxi4503 produced significant tumor necrosis compared to the controls. Subcutaneous continuous dosing infusion with Oxi4503 at 1 mg/kg/day reduced tumor growth compared to the controls, but was associated with marked systemic toxicity. Daily administration over 21 days was associated with significant mortality. Intermittent dosing of Oxi4503 (two doses, 3 days apart) produced the greatest reduction in tumor growth with minimal toxicity and conferred a significant survival advantage. Microvascular casts demonstrated significant disruption of tumor vessels.. A single dose of Oxi4503 produced significant necrosis and microvascular injury in colorectal liver metastases. Intermittent dosing with Oxi4503 produced the maximum reduction in tumor growth, minimal toxicity, and a significant improvement in survival. Oxi4503 is a potential anticancer agent. Further research into its mechanism of action and its synergistic use with other therapies is warranted.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Colorectal Neoplasms; Diphosphates; Dose-Response Relationship, Drug; Drug Administration Schedule; Infusion Pumps, Implantable; Infusions, Parenteral; Injections, Intraperitoneal; Liver Neoplasms, Experimental; Male; Mice; Mice, Inbred CBA; Microcirculation; Necrosis; Regional Blood Flow; Stilbenes; Time Factors

Radioimmunotherapy using 131I-A5B7, an anti-CEA antibody, in combination with the vascular disrupting agent, combretastatin A4-phosphate (CA-4-P, 200 mg/kg), has produced tumor cures in SW1222 colorectal xenografts. CA-4-P causes acute tumor blood vessel shutdown, which can be monitored in clinical trials using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). The purpose of this study was to determine the magnitude of the anti-vascular effect of CA-4-P in the SW1222 tumor, at 200 mg/kg and at lower, more clinically relevant doses, using conventional assays; relate effects to changes in DCE-MRI parameters and determine the corresponding effects on tumor retention of 131I-A5B7. The tumor vascular effects of 30, 100 and 200 mg/kg CA-4-P were determined, at 4- and 24-h post-treatment, using DCE-MRI, uptake of Hoechst 33342 for tumor vascular volume and conventional histology for necrosis. The effect of CA-4-P on tumor and normal tissue 131I-A5B7 retention was also determined. A significant reduction in tumor DCE-MRI kinetic parameters, the initial area under the contrast agent concentration time curve (IAUGC) and the transfer constant (Ktrans), was demonstrated at 4 h after CA-4-P, for all dose levels. These effects persisted for at least 24 h for the 200 mg/kg group but not for lower doses. A similar pattern was seen for vascular volume and necrosis. Despite this dose response, all three dose levels increased tumor retention of radio labeled antibody to a similar degree. These results demonstrate that moderate tumor blood flow reduction following antibody administration is sufficient to improve tumor antibody retention. This is encouraging for the combination of CA-4-P and 131I-A5B7 in clinical trials.

Topics: Animals; Antibodies, Monoclonal; Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Clinical Trials as Topic; Colorectal Neoplasms; Combined Modality Therapy; Drug Synergism; Humans; Iodine Radioisotopes; Kinetics; Magnetic Resonance Imaging; Mice; Necrosis; Neoplasm Transplantation; Radioimmunotherapy; Stilbenes; Time Factors

Gloriosaols A-C, isolated from Yucca gloriosa (Agavaceae), are novel phenolic compounds structurally related to resveratrol. In the present study, we show that gloriosaols possess antiproliferative and pro-apoptotic activity on tumor cells of different histogenetic origin and that their cell growth inhibition potential is higher than that of resveratrol. Despite the close similarities in their structure, gloriosaols A-C exhibited different antiproliferative potency, as the EC(50) ascending order is: gloriosaol C, gloriosaol A, gloriosaol B. Further mechanisms of gloriosaol C cytotoxicity were elucidated in detail in U937 cells, the most sensitive of the cell lines tested. The effect of gloriosaol C on cell growth turned out to be strongly dependent upon the concentration. Gloriosaol C doses lower than the EC(50) value (8 mu-icroM) blocked the cell cycle in G(0)/G(1), with a concurrent decrease in the number of cells in the G(2)/M phases of the cell cycle. At higher doses, this arrest overlaps with the occurrence of apoptosis and necrosis. In the 10-25 microM range of doses, gloriosaol C caused cell death mainly by apoptosis, as measured by hypodiploidia induction, phosphatidyl serine externalization and disruption of mitochondrial transmembrane potential. A switch in the mode of death from apoptosis to necrosis occurred at doses of gloriosaol C higher than 30 microM. Gloriosaol C was found to induce production of reactive species dose-dependently, but also to counteract their elevation in stressed cells. Thus, the different fate of cells, that is cell cycle arrest or cell death, in response to different doses of gloriosaol C might be related to the extent of induced oxidative stress.

Topics: Anticarcinogenic Agents; Apoptosis; Cell Division; Cell Line, Tumor; Cell Membrane; Cell Proliferation; G2 Phase; Humans; Membrane Potentials; Necrosis; Oxidative Stress; Phenols; Reactive Oxygen Species; Resveratrol; Stilbenes; U937 Cells

Resveratrol (trans-3,5,4',-trihydroxystilbene) is assumed to possess cancer-preventive and cancer-therapeutic properties. The aim of this project was to analyze cellular effects of resveratrol in metabolically active H4IIE rat hepatoma cells in comparison to metabolically poorly active C6 rat glioma cells. Resveratrol is rapidly taken up by both cell types and acts as a potent intracellular antioxidant. On the other hand, resveratrol in higher concentrations is relatively toxic to both cell lines as measured by the neutral red accumulation assay. In H4IIE cells, resveratrol concentrations rapidly decline to very low levels during the first hours of incubation due to formation of resveratrol glucuronides. The first resveratrol effect found at 3h after the start of resveratrol treatment was the induction of mild DNA damage as detected by the comet assay. Cell death was caused via induction of apoptosis as detected by caspase activation, oligonucleosomal DNA fragmentation and formation of apoptotic nuclei. Following DNA damage, resveratrol led to an activation of caspases 2 and 8/10 at 6h and consequently of caspase 3 at 12h, but failed to activate caspase 9. In contrast to H4IIE cells, resveratrol is not metabolised in C6 glioma cells and accumulates to concentrations which are assumed to drive the cell into necrosis. This suggests that the mode of cell death caused by resveratrol and the usefulness of resveratrol for cancer prevention and treatment critically depends on the metabolic capacity of the tumor cell to be eradicated.

Topics: Animals; Antineoplastic Agents; Antioxidants; Apoptosis; Carcinoma, Hepatocellular; Caspases; Cell Line; Cell Survival; Comet Assay; DNA Damage; DNA Fragmentation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Glioma; Necrosis; Rats; Resveratrol; Stilbenes

The contribution of bone marrow-derived circulating endothelial progenitor cells (CEPs) to tumor angiogenesis has been controversial, primarily because of their low numbers in blood vessels of untreated tumors. We show that treatment of tumor-bearing mice with vascular disrupting agents (VDAs) leads to an acute mobilization of CEPs, which home to the viable tumor rim that characteristically remains after such therapy. Disruption of this CEP spike by antiangiogenic drugs or by genetic manipulation resulted in marked reductions in tumor rim size and blood flow as well as enhanced VDA antitumor activity. These findings also provide a mechanistic rationale for the enhanced efficacy of VDAs when combined with antiangiogenic drugs.

Topics: Angiogenesis Inhibitors; Animals; Antibodies, Monoclonal; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Bone Marrow Cells; Cell Hypoxia; Cell Line, Tumor; Diphosphates; Endothelial Cells; Humans; Mice; Mice, Inbred C57BL; Mice, Nude; Necrosis; Neoplasm Transplantation; Neoplasms, Experimental; Neovascularization, Pathologic; Stem Cells; Stilbenes

Ionizing radiation is widely used in radiotherapy, in order to promote an apoptotic response in cancerous cells. Since the need to find new substances that would enhance the radiation-induced apoptosis in cancerous cells is great, we studied the effect of epigallocatechin-gallate (EGCG, a tea component), resveratrol (a wine component) and curcuma on cell proliferation and radiation-induced apoptosis in the human leukaemic cell line, EOL-1, derived from a patient with eosinophilic leukaemia. Cells were X-irradiated with 0, 2, 4, 6 or 8 Gy and cultured in the presence of EGCG, resveratrol or curcuma (concentrations ranging from 0 to 200 microM) for 1, 2 or 3 days of culture. Cell proliferation was measured using trypan blue exclusion. Apoptosis was evaluated using light microscopy (morphology study after May-Grunwald Giemsa staining) and flow cytometry (annexin-V staining). Irradiation alone induced a dose-related reduction in cell proliferation and the appearance of polyploid cells in EOL-1 cells. Additionally, EOL-1 cells underwent a dose-related increase of apoptosis which, from the second day on, was accompanied by a dose-related increase of necrosis. When cells were exposed to EGCG, resveratrol or curcuma alone, a decrease in cell proliferation was observed, beginning from 25 microM EGCG and 50 microM resveratrol and curcuma, while an increase in the percentage of apoptotic cells was noted from 50 microM EGCG, 100 microM resveratrol and curcuma in EOL-1 cells, after only one day of culture. Simultaneous exposure to X-irradiation and, EGCG, resveratrol or curcuma resulted in a synergistic decrease of cell proliferation as well as in a synergistic increase of apoptosis and necrosis. These results suggest that, depending on the concentration, EGCG, resveratrol and curcuma enhance radiation-induced apoptosis in the leukaemic cell line, EOL-1 (EGCG >resveratrol >curcuma). In order to further characterise the radiation-induced apoptosis of this leukaemic cell line, other flow cytometrical analyses are in progress.

Topics: Annexin A5; Apoptosis; Catechin; Cell Line, Tumor; Cell Membrane; Cell Proliferation; Curcuma; Dose-Response Relationship, Drug; Dose-Response Relationship, Radiation; Eosinophils; Flow Cytometry; Humans; Leukemia; Necrosis; Plant Extracts; Radiation Tolerance; Radiation, Ionizing; Resveratrol; Signal Transduction; Stilbenes; Time Factors; X-Rays

We investigated the effects of the polyphenolic phytostilbene resveratrol on the steady-state free radical (FR) concentration and mode of cell death induced by the histone deacetylase inhibitors butyrate and trichostatin A. (i) There was no correlation between cell death induction by butyrate or trichostatin A (TSA) and FR levels. (ii) Treatment with resveratrol or N-acetyl-l-cystein (NAC) of cells, in which the FR concentration was high, resulted in an almost complete reduction of FR levels. (iii) When, however, the cellular FR concentration was marginal, resveratrol caused a minor, and NAC a marked increase of FRs as well as of the extent of cell death. Thus, resveratrol and NAC acted as antioxidants only when the cellular FR levels were high, and acted as pro-oxidants when facing a low FR concentration. (iv) Since resveratrol and the antioxidant NAC exhibited analogous effects, it is concluded that the observed actions of resveratrol are due to polyphenolic redox reactions and not related to the stilbene moiety of the molecule. (v) The results indicate that the redox status of a given cell type plays an important role in determining whether resveratrol and other antioxidants promote cell death or protect cells from it.

Topics: Acetylcysteine; Animals; Antioxidants; Apoptosis; Butyrates; Cell Death; Cell Line, Tumor; Enzyme Inhibitors; Female; Free Radicals; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Intestinal Mucosa; Kinetics; Mammary Neoplasms, Animal; Mice; Necrosis; Resveratrol; Stilbenes

Ischemia-reperfusion is a critical event in the development of primary graft dysfunctions after liver transplantations. Ischemia-reperfusion causes cell injuries which are related to the successive cold preservation-warm reperfusion (CPWR) periods required by the graft. Recent evidences suggest that oxidative stress plays an important role in the development of these injuries and that mitochondrial dysfunctions are involved. The purpose of this study was to investigate the effect of the natural phytoalexin resveratrol on the prevention of liver injuries induced by 40-h cold preservation followed by a warm reperfusion. CPWR induced liver mitochondrial and cellular damages as attested by the increase in lipid peroxidation of liver membranes, the alteration of oxidative phosphorylation parameters, mitochondrial swelling and the activation of the cellular markers of necrosis and apoptosis, i.e., lactate dehydrogenase (LDH) leakage, mitochondrial cytochrome c release and caspase activation. Resveratrol inhibits lipid peroxidation and protects mitochondrial functions. It improves respiratory chain activity and prevents opening of the permeability transition pore, allowing better recovery of ATP energetic charge. Resveratrol also limits the activation of the cellular markers of necrosis and apoptosis. These protective effects could be related to the antioxidant properties of the drug but also to its membrane-stabilizing activity. Indeed, further experiments demonstrate that resveratrol is able to prevent the release of cytochrome c caused by oxygen deprivation in isolated liver mitochondria. These data demonstrate that resveratrol ameliorates the liver injury induced by CPWR and appears as a promising drug to improve the primary function of the grafted liver after transplantation.

Topics: Adenosine Triphosphate; Animals; Antioxidants; Apoptosis; Caspases; Cold Temperature; Cytochromes c; Dose-Response Relationship, Drug; In Vitro Techniques; L-Lactate Dehydrogenase; Lipid Peroxidation; Liver; Male; Mitochondria, Liver; Mitochondrial Membranes; Mitochondrial Swelling; Necrosis; Oxidative Phosphorylation; Rats; Rats, Wistar; Reperfusion; Reperfusion Injury; Resveratrol; Stilbenes; Time Factors

AVE8062, a derivative of combretastatin A-4, has a strong stanching effect on tumour blood flow (TBF), which leads to complete blockage of nutrient supply to solid tumours and their necrosis. Previously, we reported that TBF stasis is due to increased arteriolar resistance caused by AVE8062 and a lasting decrease in perfusion pressure in tumour-feeding vessels. Here, we measured changes in TBF in rat solid tumour LY80 during continuous administration of AVE8062-like epinephrine or four catecholamines that are unlike AVE8062 (norepinephrine, dopamine, methoxamine, and metaraminol) to the region of increased vascular resistance. Venous administration of 0.3 mg ml(-1) epinephrine caused TBF to fall immediately to near zero, where it remained throughout the administration period. With a 30-min drug administration, TBF began to recover immediately when drug administration halted. With a 60-min epinephrine administration, TBF recovered somewhat, but not to the previous level. With drug administration of 120 min, TBF did not recover during the subsequent 8 h. Likewise, 0.1 mg ml(-1) epinephrine produced irreversible occlusion after 120 min of administration. In contrast, 120 min of administration of the four other catecholamines resulted in no occlusion. Only the group given 0.3 mg ml(-1) epinephrine (not that given methoxamine) showed significantly greater necrosis than the control. We conclude that, for epinephrine to cause irreversible occlusion of these vessels, a marked decrease in perfusion pressure in tumour-feeding blood vessels is necessary and should be maintained for 2 h. This conclusion is consistent with the previously demonstrated mechanism of irreversible arteriole occlusion caused by AVE8062. AVE8062 and epinephrine appear to have the same mechanism of action regarding induction of tumour blood flow stasis.

Topics: Animals; Antineoplastic Agents, Phytogenic; Catecholamines; Epinephrine; Necrosis; Neoplasms, Experimental; Rats; Regional Blood Flow; Sarcoma; Serine; Soft Tissue Neoplasms; Stilbenes

Resveratrol, a polyphenol present in many plant species, exhibits a wide range of biological and pharmacological activities both in vitro and in vivo. It has been shown to exert a potent chemopreventive effect in carcinogenesis models and to induce cell growth inhibition and apoptosis in human tumour cells, including melanoma cells. Malignant melanoma is considered to be a chemotherapy-refractory tumour, and the commonly used anticancer drugs do not seem to modify the prognosis of metastatic disease. To further evaluate the therapeutic potential of resveratrol in the treatment of melanoma, we selected three human melanoma cell lines with different levels of resistance to temozolomide (TMZ), an antitumour triazene compound. The cell lines were subjected to resveratrol treatment and analysed for cell growth inhibition, cell cycle perturbation and apoptosis induction. We found that resveratrol markedly impaired proliferation of both the TMZ-sensitive M14 and the TMZ-resistant SK-Mel-28 and PR-Mel cell lines. The latter cell line was two-fold more resistant to the drug than M14 and SK-Mel-28 cells. The sensitivity of normal human keratinocytes to resveratrol was found to be significantly higher than that of M14 and SK-Mel-28 cells and similar to that of the PR-Mel cell line. This suggests a possible good in vivo therapeutic index for resveratrol. Our results also show that the growth-inhibitory effect of resveratrol on melanoma cells is mainly due to its ability to induce S-phase arrest and apoptosis. Taken together, our data indicate that resveratrol is an interesting candidate for the treatment of advanced melanoma.

Topics: Antineoplastic Agents; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Dacarbazine; Drug Resistance, Neoplasm; Humans; Inhibitory Concentration 50; Keratinocytes; Melanoma; Necrosis; Poly(ADP-ribose) Polymerases; Resveratrol; S Phase; Stilbenes; Temozolomide; Time Factors

The mechanism of tumor cell killing by OXI4503 was investigated by studying vascular functional and morphological changes post drug administration. SCID mice bearing MHEC5-T hemangioendothelioma were given a single dose of OXI4503 at 100 mg/kg. Tumor blood flow, measured by microsphere fluorescence, was reduced by 50% at 1 hr, and reached a maximum level 6-24 hr post drug treatment. Tumor vascular permeability, measured by Evan's blue and hemoglobin, increased significantly from 3 hr and peaked at 18 hr. The elevated tumor vessel permeability was accompanied by an increase in vascular endothelial growth factor (VEGF) from 1 hr post drug treatment. Immunohistochemical staining for CD31 and laminin showed that tumor blood vessels were affected as early as 3 hr but more prominent from 6 hr. From 12 hr, the vessel structure was completely destroyed. Histopathological and double immunohistochemical staining showed morphological change and induction of apoptosis in endothelial cells at 1-3 hr, followed by tumor cell necrosis from 6-72 hr. There were no statistically significant changes of Evan's blue and hemoglobin contents in liver tissue over the time course. These results suggest that OXI4503 selectively targets tumor blood vessels, and induces blood flow shutdown while it enhances tumor blood vessel permeability. The early induction of endothelial cell apoptosis leads to functional changes of tumor blood vessels and finally to the collapse of tumor vasculature, resulting in massive tumor cell necrosis. The time course of the tumor vascular response observed with OXI4503 treatment supports this drug for development as a stand alone therapy, and also lends support for the use of the drug in combination with other cancer therapies.

Topics: Animals; Apoptosis; Diphosphates; Endothelial Cells; Female; Fluorescence; Hemangioendothelioma; Immunohistochemistry; Male; Mice; Mice, SCID; Necrosis; Permeability; Regional Blood Flow; Stilbenes; Vascular Endothelial Growth Factor A

Vegetables and fruit help the prevention and the therapy of several kinds of cancer because they contain micronutrients, a class of substances that have been shown to exhibit chemopreventive and chemotherapeutic activities. In the present study the effects of resveratrol (100 and 200 microM), a phytoalexin found in grapes, and of the ethanolic extract of propolis (50 and 100 microg/ml), a natural honeybee hive product, were tested in androgen-resistant prostate cancer cells (DU145), a cell line resembling the last stage of prostate carcinoma. A comparison between the activity of these micronutrients and vinorelbine bitartrate (Navelbine), a semi-synthetic drug normally used in the therapy of prostate cancer, was conducted. Several biochemical parameters were tested, such as cell viability (MTT assay), cell membrane integrity (lactate dehydrogenase release), cell redox status (nitric oxide formation, reactive oxygen species production, reduced glutathione levels), genomic DNA fragmentation (COMET assay) with special attention on the presence of apoptotic DNA damage (TUNEL test), and possible mitochondrial transmembrane potential alteration (deltapsi). Our results point out the anticancer activity of resveratrol and propolis extract in human prostate cancer, exerting their cytotoxicity through two different types of cell death: necrosis and apoptosis, respectively. The data obtained suggest the possible use of these micronutrients both in alternative to classic chemotherapy, and in combination with very low dosage of vinorelbine (5 microM).

Topics: Apoptosis; Cell Line, Tumor; Cell Survival; Humans; Male; Necrosis; Propolis; Prostatic Neoplasms; Reactive Oxygen Species; Resveratrol; Stilbenes

This overview summarizes the preclinical development of tubulin-depolymerizing agents as vascular targeting agents, leading to the identification of combretastatin A4P (CA4P).. The murine tumor CaNT was implanted s.c. in the dorsum of CBA mice. Vascular function was determined after treatment using the perfusion marker Hoechst 33342 and fluorescence microscopy. Tumor cell response was assessed by using an excision assay and by measuring the delay in growth of treated tumors.. At doses that approximated one-half the maximum tolerated dose (MTD) in CBA mice, none of the agents evaluated-i.e., taxol, melphalan, 5-fluorouracil, doxorubicin, cisplatin, gemcitabine, and irinotecan-induced any significant reduction in perfused vascular volume within the tumor mass. In contrast, CA4P at a dose of 100 mg/kg, which approximates one-fifth the MTD, induced a greater than 80% reduction in vascular function. Although colchicine did induce vascular shutdown, this occurred only at doses approximating the MTD. Histologic evaluation demonstrated that continued growth and repopulation of the tumor mass was the result of a surviving rim of viable tumor cells at the tumor periphery.. These results confirm the ability of CA4P to selectively compromise vascular function in experimental tumors, inducing extensive tumor cell death at well-tolerated doses. However, despite these effects, no growth retardation is obtained when CA4P is administered alone in a single dose. The continued growth and repopulation of the tumor mass occurs from a narrow rim of viable cells at the periphery. If, as is believed, these remaining cells are the ones most sensitive to conventional cytotoxic and macromolecular approaches, CA4P and other vascular targeting agents offer considerable potential for enhancing the effectiveness of existing and emerging cancer therapies.

Topics: Animals; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Benzimidazoles; Dose-Response Relationship, Drug; Mice; Mice, Inbred CBA; Microscopy, Fluorescence; Necrosis; Neoplasm Transplantation; Neovascularization, Pathologic; Radiation-Protective Agents; Stilbenes; Time Factors; Tubulin; Tumor Cells, Cultured

This study investigates the enhancement of the vascular targeting activity of the tubulin-binding agent combretastatin A4 phosphate (CA4P) by various inhibitors of nitric oxide synthases.. The syngeneic tumors CaNT and SaS growing in CBA mice were used for this study. Reduction in perfused vascular volume was measured by injection of Hoechst 33342 24 h after drug administration. Necrosis (hematoxylin and eosin stain) was assessed also at 24 h after treatment. Combretastatin A4 phosphate was synthesized by a modification of the published procedure and the nitric oxide synthase inhibitors L-NNA, L-NMMA, L-NIO, L-NIL, S-MTC, S-EIT, AMP, AMT, and L-TC, obtained from commercial sources.. A statistically significant augmentation of the reduction in perfused vascular volume by CA4P in the CaNT tumor was observed with L-NNA, AMP, and AMT. An increase in CA4P-induced necrosis in the same tumor achieved significance with L-NNA, L-NMMA, L-NIL, and AMT. CA4P induced little necrosis in the SaS tumor, but combination with the inhibitors L-NNA, L-NMMA, L-NIO, S-EIT, and L-TC was effective.. Augmentation of CA4P activity by nitric oxide synthase inhibitors of different structural classes supports a nitric oxide-related mechanism for this effect. L-NNA was the most effective inhibitor studied.

Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents, Phytogenic; Benzimidazoles; Enzyme Inhibitors; Fluorescent Dyes; Mice; Mice, Inbred CBA; Models, Chemical; Necrosis; Neovascularization, Pathologic; Nitric Oxide Synthase; Stilbenes; Time Factors; Tubulin; Tumor Cells, Cultured

Combretastatin A-4-phosphate (CA-4-P) is a tubulin-binding compound currently in clinical trial as a tumor vascular-targeting agent. In endothelial cells, CA-4-P is known to cause microtubule depolymerization, but little is known about its subsequent effects on cell morphology and function. Here, we demonstrate that within minutes of endothelial cell exposure to CA-4-P, myosin light chain (MLC) was phosphorylated, leading to actinomyosin contractility, assembly of actin stress fibers, and formation of focal adhesions. These cytoskeletal alterations appeared to be a consequence of Rho activation, as they were abolished by either the Rho inhibitor C3 exoenzyme or Rho-kinase inhibitor Y-27632. In response to CA-4-P, some cells rapidly assumed a blebbing morphology in which F-actin accumulated around surface blebs, stress fibers misassembled into a spherical network surrounding the cytoplasm, and focal adhesions appeared malformed. Blebbing was associated with decreased cell viability and could be inhibited by Rho/Rho-kinase inhibitors or by blocking the CA-4-P-mediated activation of stress-activated protein kinase-2/p38. The extracellular-regulated kinases 1 and 2 (ERK-1/2) were shown to protect against blebbing since blebbing was attenuated on ERK-1/2 stimulation and was up-regulated by specific inhibition of ERK-1/2 activation. The use of MLC kinase (MLCK) and myosin adenosine triphosphatase inhibitors led us to propose a role for MLCK and myosin activity independent of MLC phosphorylation in regulating the blebbing process. CA-4-P-mediated contractility and blebbing were associated with a Rho-dependent increase in monolayer permeability to dextrans, suggesting that such functional changes may be important in the rapid response of the tumor endothelium to CA-4-P in vivo.

Topics: Actins; Acute-Phase Proteins; Antineoplastic Agents, Phytogenic; Capillary Permeability; Cell Membrane; Cytoskeleton; Endothelium, Vascular; Focal Adhesions; Humans; Mitogen-Activated Protein Kinases; Myosin-Light-Chain Kinase; Myosins; Necrosis; Stilbenes; Stress Fibers

The utility of combining the vascular targeting agents 5,6-dimethyl-xanthenone-4 acetic acid (DMXAA) and combretastatin A-4 disodium phosphate (CA4DP) with the anticancer drugs cisplatin and cyclophosphamide (CP) was evaluated in experimental rodent (KHT sarcoma), human breast (SKBR3) and ovarian (OW-1) tumor models. Doses of the vascular targeting agents that led to rapid vascular shutdown and subsequent extensive central tumor necrosis were identified. Histologic evaluation showed morphologic damage of tumor cells within a few hours after treatment, followed by extensive hemorrhagic necrosis and dose-dependent neoplastic cell death as a result of prolonged ischemia. Whereas these effects were induced by a range of CA4DP doses (10-150 mg/kg), the dose response to DMXAA was extremely steep; doses < or = 15 mg/kg were ineffective and doses > or = 20 mg/kg were toxic. DMXAA also enhanced the tumor cell killing of cisplatin, but doses > 15 mg/kg were required. In contrast, CA4DP increased cisplatin-induced tumor cell killing at all doses studied. This enhancement of cisplatin efficacy was dependent on the sequence and interval between the agents. The greatest effects were achieved when the vascular targeting agents were administered 1-3 hr after cisplatin. When CA4DP (100 mg/kg) or DMXAA (17.5 mg/kg) were administered 1 hr after a range of doses of cisplatin or CP, the tumor cell kill was 10-500-fold greater than that seen with chemotherapy alone. In addition, the inclusion of the antivascular agents did not increase bone marrow stem cell toxicity associated with these anticancer drugs, thus giving rise to a therapeutic gain.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Blood Vessels; Cisplatin; Cyclophosphamide; Dose-Response Relationship, Drug; Drug Synergism; Female; Humans; Mice; Mice, Inbred C3H; Mice, Nude; Necrosis; Neovascularization, Pathologic; Sarcoma, Experimental; Stilbenes; Tumor Cells, Cultured; Xanthenes; Xanthones

The ability of combretastatin A-4 disodium phosphate (CA4DP) to induce vascular damage and enhance the radiation response of murine tumors was investigated.. A C3H mouse mammary carcinoma transplanted in the foot of CDF1 mice and the KHT mouse sarcoma growing in the leg muscle of C3H/HeJ mice were used. CA4DP was dissolved in saline and injected intraperitoneally. Tumor blood perfusion was estimated using 86RbCl extraction and Hoechst 33342 fluorescent labelling. Necrotic fraction was determined from histological sections. Tumors were locally irradiated in non-anaesthetised mice and response assessed by local tumor control for the C3H mammary carcinoma and in vivo/in vitro clonogenic cell survival for the KHT sarcoma.. CA4DP decreased tumor blood perfusion and increased necrosis in a dose-dependent fashion in the C3H mammary carcinoma, which was maximal at 250 mg/kg. The decrease in perfusion and induction of necrosis by CA4DP was more extensive in the KHT sarcoma. CA4DP enhanced radiation damage in both tumor types. In the KHT sarcoma this enhancement was independent of whether the drug was given before or after irradiating, whereas for C3H mammary carcinoma the enhancement was only significant when administered at the same time or after the radiation, with no enhancement seen if CA4DP was given before. These effects were drug-dose dependent. CA4DP did not enhance radiation damage in normal skin.. CA4DP enhanced radiation damage in the two tumor models without enhancing normal tissue damage. These radiation effects were clearly consistent with the anti-vascular action of CA4DP.

Topics: Animals; Antineoplastic Agents, Phytogenic; Combined Modality Therapy; Mammary Neoplasms, Experimental; Mice; Mice, Inbred C3H; Necrosis; Neoplasm Transplantation; Sarcoma, Experimental; Stilbenes

To investigate the activity of combretastatin A-4 disodium phosphate in a transplanted C3H mouse mammary carcinoma and several murine spontaneous tumors.. The C3H mammary carcinoma was grown in the right rear foot of female CDF1 mice and treated when 200 mm3 in size. Spontaneous tumors (341-1437 mm3 in size) arose at different sites in female CDF1 mice that, 19-21 months earlier, had been irradiated. Oxygen partial pressure (pO2) distributions in the C3H tumors were measured with an Eppendorf oxygen electrode at various times after injecting combretastatin (100 mg/kg, i.p.) in restrained, nonanesthetized mice. Immediately after measurement, tumors were excised and necrotic fraction determined from histological sections. In the spontaneous tumors, pO2 was measured before and 3 h after giving combretastatin. The location of these spontaneous tumors required that measurements be made in anesthetised animals, achieved by injecting a mixture of hypnorm and diazepam.. In untreated C3H tumors, the mean (+/- 1 SE) percentage of pO2 values < or = 2.5 mmHg was 32% (+/- 11). This was significantly (Student's t-test; p < 0.05) increased to 74% (+/- 4) within 1 h after injecting combretastatin, and remained at this level for at least 6 h, although some recovery was seen at 12 and 24 h. The necrotic fraction in control tumors was 1.9% (+/- 0.4) and this was significantly increased to 16.1% (+/- 3.7) 24 h after drug administration. In spontaneous tumors, the pO2 measurements indicated that 5 of 6 showed some response to combretastatin, although the degree of change was variable.. Combretastatin increased tumor hypoxia and necrosis in the C3H mammary carcinoma, consistent with the induction of vascular damage. Drug-induced changes in pO2 were also found in spontaneous tumors, suggesting that the activity of this drug is not restricted to transplanted tumors alone.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Hypoxia; Drug Screening Assays, Antitumor; Female; Mammary Neoplasms, Experimental; Mice; Necrosis; Neoplasms; Oxygen Consumption; Partial Pressure; Stilbenes

Combretastatins have tubulin-binding activity and are being investigated for their toxicity against tumour vasculature. We report the use of 31P and 'H magnetic resonance (MR) spectroscopy and 1H MR imaging for monitoring the effects of combretastatin A-4 prodrug (100mg/kg, i.p.) on energy metabolism and necrosis, respectively, in the C3H murine mammary tumour.. The tumours (volume ca. 200mm3) were grown in the hind foot of mice. MR examinations were performed without anaesthesia within a 7.1 Tesla magnet. 31P MRS (TR = 6 s) was performed before treatment and at 1-, 2-, 3-, and 24-h after injection of drug or saline via an i.p. line. 1H MRS (PRESS; 24microl voxel; TR = 2 s; TE = 135 ms) and both T1-weighted (TR = 0.2 s; TE = 0.02 s) and T2-weighted (TR = 2 s; TE = 0.20 s) 1H MRI were performed before treatment and 2.5 and 24 h afterwards.. The ratio beta-nucleotide triphosphate/inorganic phosphate fell by 33% within 1 h of treatment and remained constant for a further 2 h. A small but significant fall in pH (by 0.11 units) was observed at 1 h. Although an increase in the 1H MR spectroscopy signal at about 1.32 ppm (predominantly from lactate) was observed in some tumours following combretastatin treatment, this effect was not seen consistently. No changes in the intensity of T2-weighted 1H MR images or in tumour necrosis (measured histologically) were detected within 3 h of treatment.. The reduction in tumour energetics and pH was consistent with a reduction in tumour blood flow but this occurred before any significant incidence of haemorrhagic necrosis was detected. The combretastatin dose used to achieve these effects was less than one tenth of the maximum tolerated dose in mice.

Topics: Animals; Antineoplastic Agents, Phytogenic; Bibenzyls; Drug Screening Assays, Antitumor; Energy Metabolism; Hydrogen; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Mammary Neoplasms, Animal; Mice; Necrosis; Phosphorus; Stilbenes

The aim of this study was to evaluate the antitumor efficacy of combretastatin A-4 disodium phosphate (combretastatin prodrug) in the rodent KHT sarcoma model either alone or in combination with radiation therapy.. KHT tumors were grown in C3H/HeJ mice. Combretastatin A-4 prodrug was injected intraperitoneally at doses ranging from 10 to 100 mg/kg. Tumors were irradiated in unanesthetized mice using a 137Cs source. Tumor response to combretastatin A-4 prodrug was assessed by histological evaluations as well as an in vivo to in vitro cell survival assay.. Histological evaluation showed morphological damage of tumor cells within a few hours after drug treatment, followed by extensive central necrosis. Administering increasing doses of combretastatin A-4 prodrug to tumor-bearing mice resulted in a dose-dependent increase in cell killing irrespective of whether the tumors were irradiated or not. When combined with radiation, a 100 mg/kg dose of combretastatin A-4 prodrug reduced tumor cell survival 10-500-fold lower than that seen with radiation alone. Further, the shape of the cell survival curve observed following the combination therapy suggested that including combretastatin in the treatment had a major effect on the radiation-resistant hypoxic cell subpopulation associated with this tumor.. The present results demonstrated that in the KHT sarcoma, combretastatin A-4 prodrug caused rapid vascular shutdown, a concentration-dependent direct cell killing, and effective enhancement of the antitumor effects of radiation therapy.

Topics: Animals; Antineoplastic Agents, Phytogenic; Blood Vessels; Combined Modality Therapy; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; Mice; Mice, Inbred C3H; Necrosis; Sarcoma, Experimental; Stilbenes

Oral administration of an ethanol extract of the root of Astragalus membranaceus alleviated liver injury induced by stilbenemidine. Pre-administration in mice reduced elevated SGPT levels and subacute toxicity of stilbenemidine, decreased pentobarbital-induced loss of righting reflex and protected hepatic cells from pathological changes.

Topics: Alanine Transaminase; Animals; Astragalus propinquus; Drugs, Chinese Herbal; Female; Liver; Liver Diseases; Male; Mice; Mice, Inbred Strains; Necrosis; Pentobarbital; Sleep; Stilbenes

The acute toxicity of the carcinogen trans-4-dimethylaminostilbene was studied in Wistar rats. The animals die after oral administration of 50 mg/kg (LD50) with a latency period of 11 days. Specific lesions of the stomach epithelium together with acute bone marrow incapacity and toxic effects on peripheral blood cells lead to acute anemia, which is considered to be the cause of death. Histological observations indicate that the stomach lesions develop in three phases. Firstly, necroses appear in the proliferative area predominantly in the antrum. This leads, secondly, to cystic transformation of the antrum, cardia, and Brunner's glands and further to peptic erosions and ulcerations. Thirdly, mitotic activity increases. With lethal doses, cell replacement remains incomplete. There ist a correlation between the proliferation rate of different cell types and their susceptibility; but this cannot entirely account for the tissue-specific, systemic effects of trans-4-dimethylaminostilbene. Metabolic activation is also involved, since enzyme induction with methylcholanthrene inhibits toxicity. The study disclosed a new target tissue which may now be used to investigate the mechanism of action of reactive metabolites of an aromatic amine in acute experiments. The same stomach lesions were also observed with adriamycin. With this compound, however, the intestine is also involved.

Topics: Acute Disease; Alanine Transaminase; Animals; Aspartate Aminotransferases; Body Weight; Carcinogens; Chronic Disease; Doxorubicin; Eating; Female; Gastric Mucosa; Lethal Dose 50; Male; Mice; Necrosis; Rats; Rats, Inbred Strains; Species Specificity; Stilbenes; Stomach Diseases

Daily administration of a brominated triphenylethylene (TBP), to rats which received 20 mg of DMBA p. o. inhibits mammary carcinogenesis. The effect appears even with very small doses (i ppm in the diet) and seems to be dose related. With one exception (an adenofibroma) the tumours in control and treated animals were malignant. Administration of TBP prevents the appearance of corporea lutea in the ovaries but not the usual necrosis of the adrenal cortex.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Adenocarcinoma; Adenofibroma; Adrenal Cortex; Animals; Benz(a)Anthracenes; Corpus Luteum; Estradiol Congeners; Female; Mammary Neoplasms, Experimental; Necrosis; Organ Size; Ovary; Rats; Stilbenes

Topics: Adrenal Glands; Animals; Body Weight; Female; Heparin Antagonists; Infarction; Kidney; Kidney Cortex Necrosis; Liver; Necrosis; Organ Size; Ovary; Pituitary Gland; Pituitary Hormones, Posterior; Quaternary Ammonium Compounds; Rats; Spleen; Stilbenes; Thyroid Gland; Tissue Extracts; Uterus