Biomedical subjects

M Kochi

Publications and source records attributed to M Kochi.

At least 91 records · Page 5Linked to original sources

PubMedDate not supplied

Production of hydrogen peroxide in cancerous tissue by intravenous administration of sodium 5,6-benzylidene-L-ascorbate.

We investigated whether the antitumor action of sodium 5,6-benzylidene-L-ascorbate (SBA) is mediated via oxidation-involved mechanism, in three different systems: 3'-methyl-4-dimethylaminoazobenzene (DAB)-induced rat hepatocellular carcinoma (in vivo), its homogenate (semi in vivo), and cultured cells (in vitro). Oral intake of DAB irreversibly produced hepatocellular carcinoma in rats, with a maximum incidence of carcinogenesis after 4 months. Intravenous administration of SBA induced vacuolar, eosinophilic degeneration and nuclear debris, producing greater amounts of ESR signal of ascorbate radical and hydrogen peroxide (H2O2)-derived chemiluminescence (CL) (H2O2-CL) in the cancerous tissue than in the normal tissue. When SBA was directly added to the homogenates, higher amounts of ascorbate radical and H2O2-CL were generated in cancerous tissues. When SBA was added to the RPMI1640 medium supplemented with 10% fetal bovine serum, methionine was oxidized to methionine sulfoxide and H2O2 was produced in amounts that sufficiently induce apoptotic cell death in human promyelocytic leukemic HL-60 cells. Cytotoxic activity of SBA was significantly reduced by catalase. These data suggest that antitumor activity of SBA in vivo might at least in part be due to H2O2, produced from SBA.

Animals↗

PubMedDate not supplied

Amino acid utilization during apoptosis in HL-60 cells.

Human promyelocytic leukemia (HL-60), human squamous carcinoma (HSC-2, HSC-4, NA) and rat pheochromocytoma (PC-12) cell lines consumed nonpolar (Leu, Ile, Val, Cys, Met, Phe), neutral polar (Gln, Ser, Thr, Tyr) and basic polar amino acids (Arg, Lys, His), whereas they produced nonpolar (Gly, Pro, Ala) and acidic polar amino acids (Glu). The consumption rate of Ser and Arg by HL-60 cells was significantly higher than that of other cell lines. During apoptosis of HL-60 cells induced by either sodium ascorbate, sodium 5,6-benzylidene-L-ascorbate (SBA) or dopamine, the consumption of nonpolar and polar amino acids (neutral or acidic) generally declined, except for Cys, Met and Arg, whereas the production of Gly and Glu was slightly increased. Since the intracellular concentration of cGMP was not significantly changed before and after ascorbate treatment, nitric oxide might not be involved in the ascorbate-induced apoptosis. The present data demonstrates that consumption rate of nonpolar and polar amino acid, whether neutral, acidic or basic, was reduced almost evenly during the apoptosis induction. This suggests that apoptosis-associated changes in the amino acid utilization might not be significantly affected by ATP depletion, which might be caused by mitochondrial dysfunction.

Adenosine Triphosphate↗

PubMedDate not supplied

Interaction between sodium 5,6-benzylidene-L-ascorbate and gallic acid.

The interaction between sodium 5,6-benzylidene-L-ascorbate (SBA) and gallic acid was investigated by two different parameters: radical intensity and cytotoxicity induction. These compounds produced ESR signals of radicals under alkaline conditions. The addition of increasing concentrations of SBA completely scavenged the gallate radical and replaced the latter with its ascorbate radical. On the other hand, gallic acid dose-dependently enhanced the radical intensity of SBA. Both of these two compounds dose-dependently reduced the viable cell number of human squamous carcinoma HSC-2 cells without inducing internucleosomal DNA cleavage. Electron micrographs of the dying cells demonstrate the irreversible degenerative changes especially in the cytoplasm of the cells. The cytotoxic activity of gallic acid was almost completely eliminated by catalase, whereas SBA was totally insensitive to catalase. When these two compounds were mixed together before adding to HSC-2 cells, the cytotoxic activity of gallic acid was significantly reduced by SBA, whereas that of SBA was not reduced by gallic acid. SBA dose-dependently reduced the gallate oxidation in the culture medium. The interaction between SBA and gallic acid may modify their individual biological activity.

Antineoplastic Agents↗

PubMedDate not supplied

Induction of non-apoptotic cell death by sodium 5,6-benzylidene-L-ascorbate in a human salivary gland tumor cell line.

We investigated whether sodium 5,6-benzylidene-L-ascorbate (SBA) induces apoptotic cell death in a human salivary gland tumor cell line HSG, using two different cytochemical methods. Millimolar concentrations of SBA dose-dependently reduced the viable cell number of HSG cells, accompanied by the detachment of dying cells from the culture plates. The nuclei of the dying cells were not stained with TUNEL reagent, indicating the lack of DNA nicks or fragments. On the other hand, the nuclei of epigallocatechin gallate (EGCG)-treated cells (positive control) were TUNEL-positive, demonstrating the production of DNA nicks or fragments. Furthermore, the cytoplasms of SBA-treated cells were not stained with M30 monoclonal antibody, which reacts with the degradation products of cytokeratin 18 by the activated caspases, in contrast to those of EGCG-treated cells. These results suggest that SBA induces non-apoptotic cell death, possibly necrosis, in HSG cells.

Antibodies, Monoclonal↗

PubMedDate not supplied

Changes in intracellular concentrations of amino acids and polyamines during the apoptosis of HL-60 cells.

Possible changes in the intracellular concentrations of amino acids and polyamines were investigated during the apoptosis of human promyelocytic leukemic HL-60 cells. Treatment of HL-60 cells with sodium 5,6-benzylidene-L-ascorbate (SBA) or sodium ascorbate induced apoptotic cell death characterized by chromatin condensation, nuclear fragmentation, loss of microvilli, and production of numerous vacuoles and apoptotic bodies. The apoptosis was accompanied by a significant increase in the intracellular concentration of almost all neutral and basic amino acids (regardless of their polarity). On the other hand, the concentration of glutamic acid, the most abundant amino acid in the cells, was significantly reduced. These data suggest the reduced amino acid utilization and possible membrane impairment, especially in SBA-treated cells. Among three major polyamines, the intracellular concentration of putrescine rapidly declined, whereas that of spermidine and spermine was almost unchanged during apoptosis. Conversely, the concentration of putrescine, but not that of spermidine and spermine, was significantly increased during the chemically-induced carcinogenesis of mouse liver tissue. The present study demonstrates that the putrescine level is the most sensitive to the proliferation capability of the cells, among three polyamines, and provides an early marker for apoptosis and proliferation.

Amino Acids↗

PubMedDate not supplied

Effect of cobalt ion on radical intensity and cytotoxic activity of antioxidants.

The effect of CoCl2 on the cytotoxic activity of various antioxidants against human oral tumor cell lines (HSC-2, HSG) and normal human gingival fibroblasts (HGF) was investigated. Noncytotoxic concentrations of CoCl2 significantly reduced the cytotoxic activity of sodium ascorbate, gallic acid, epigallocatechin gallate (EGCG), curcumin and dopamine, but not that of sodium 5,6-benzylidene-L-ascorbate (SBA) and benzaldehyde. Among these compounds, benzaldehyde showed the most prominent tumor-specific cytotoxic action. ESR spectroscopy showed that these antioxidants produced radicals under alkaline condition and that their radical intensity was transiently enhanced and finally disappeared by addition of CoCl2. Antioxidants which are sensitive to CoCl2 generally had higher cytotoxic activity and oxidation potential (measured by NO monitor) and addition of CoCl2 significantly reduced their oxidation potential. The present study suggests that cobalt ion stimulates the oxidation of antioxidants to their inactive products.

Antioxidants↗

PubMedDate not supplied

Tumor-specific action of sodium 5,6-benzylidene-L-ascorbate in N-nitrosodiethylamine-administered mouse model.

In order to elucidate the mechanisms of antitumor action of sodium 5,6-benzylidene-L-ascorbate (SBA), we established a mouse hepatocellular carcinoma model by oral administration of N-nitrosodiethylamine (NDA) and examined the ascorbate radical intensity and putrescine content in the liver. The oral intake of NDA induced precancerous lesion and a significant increase in putrescine content among three major polyamines. When the oral intake of NDA was stopped, morphological changes were reversed. ESR spectroscopy showed that the homogenate of precancerous tissues produced greater amounts of ascorbate radical than that of normal liver tissue. Intravenous administration of SBA 30 minutes before removal of the liver prolonged the higher level of ascorbate radical generation in the homogenate of precancerous tissue. The antitumor activity of SBA might be due to the long-term production of radicals in tumor tissues by its prooxidant action.

Animals↗

PubMedDate not supplied

Induction of tumor degeneration by sodium benzylideneascorbate.

Intravenous administration of sodium benzylideneascorbate (SBA) rapidly necrotized inoperable human lung cancer, and induced degeneration of 3'-methyl-4-dimethylaminoazobenzene-induced rat hepatocellular carcinoma (vacuolar, eosinophilic degeneration, nuclear debris) without affecting the serum glutamic oxaloacetic transaminase, gamma-glutamyl transpeptidase and total protein levels. Cultured normal human lung and skin fibroblasts, and human glioma and glioblastoma cell lines were relatively resistant to SBA, when compared to human myelogenous leukemic cell lines. SBA had no apparent host immunopotentiation activity such as stimulation of cytokine action or production; activation of monocyte or polymorphonuclear cells; or modulation of poly (ADP-ribose) glycohydrolase activity. The data suggest that the antitumor activity of SBA might be produced by direct action of authentic SBA or its metabolized form(s), rather than by immunopotentiation of the hosts.

Animals↗

PubMedDate not supplied

Antiproliferative effect of YM881 (SMANCS) on glioma cells in vitro.

Growth inhibitory activity of YM881 (SMANCS) against 3 human cultured cell lines and one rat cultured cell line derived from glioma cells was assessed quantitatively. YM881 showed potent cytotoxicity against all glioma cell lines tested; the IC50 of this drug was 1.9-8.4 micrograms/ml. YM881 may be classified as a concentration-dependent drug but it has also a time-dependent effect. Flow cytometric studies of the DNA histogram showed accumulation in the G2-M phase with YM881. These findings suggest that YM881 may be useful in the treatment of glioma.

Animals↗

PubMedDate not supplied

Antioxidative activity of benzylideneascorbate and its effect on adriamycin-induced cardiotoxicity.

The in vitro antioxidative activity of benzylideneascorbate (SBA) and the in vivo effect on adriamycin (ADR)-induced cardiotoxicity in a mouse model were investigated. The radical-scavenging activity of SBA was assayed in terms of reduction of chemiluminescence induced by O2-, generated in xanthine/xanthine oxidase and macrophage/phorbol myristate acetate reaction systems. SBA showed a strong antioxidative activity (IC50 = 3 to 4 microM) in both assay systems, though its activity was weaker than that of ascorbic acid (Asc). In the assay of the antioxidative activity against auto-oxidation of linolenic acid, SBA was stable and retained its potency for a long period of time in comparison with Asc, 6-palmitoylascorbic acid (6-P-Asc) and cysteamine (CysNH2). Electron spin resonance examination indicated that SBA strongly scavenged both superoxide anion and hydroxy radical. The in vivo protective effect of SBA against ADR-induced cardiotoxicity, in which active oxygen radicals play a role, was examined. The serum creatine phosphokinase activity, a parameter of cardiotoxicity, was remarkably increased from the 3rd day until the 4th day after ADR treatment. This elevation was significantly suppressed by SBA treatment, whereas Asc, 6-P-Asc and CysNH2 were ineffective. SBA could have clinical potential for the treatment of diabetes and other disorders in which active oxygen species play a pathogenic role.

Animals↗

PubMedDate not supplied

Effect of metals and their antagonists on the radical intensity and cytotoxicity of ascorbates.

Five heavy metal antagonists were compared for their specificity of chelating action against copper (CuCl, CuCl2) and iron (FeCl2, FeCl3). ESR spectroscopy showed that both copper and iron significantly enhanced the radical intensity of ascorbate and sodium 5,6-benzylidene-L-ascorbate (SBA). Equimolar concentrations of dimercaprol efficiently chelated all these metals, thus significantly reducing their stimulation effects. On the other hand, the chelating action of penicillamine, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid was limited to CuCl and CuCl2 whereas deferoxamine mesylate (DFO) was a specific iron chelator. The cytotoxic activity of sodium ascorbate was augmented by DFO, but diminished by FeCl3. The simultaneous addition of DFO and FeCl3 counteracted each other, thus neutralizing their individual effects. The cytotoxic activity of both sodium ascorbate and SBA was significantly enhanced by CuCl2 and this stimulation effect of CuCl2 was effectively chelated by DTPA. The present study demonstrates the specificity of the chelating action of these five antagonists, suggesting the possible application of these different types of antagonists for the prevention of the pathogenic diseases catalyzed by the corresponding metals.

Ascorbic Acid↗

PubMedDate not supplied

Chelating effect of human serum proteins on metal-catalyzed ascorbate radical generation.

Purified human serum albumin and immunoglobulin G (IgG) were investigated for their metal-chelating activity, using ESR spectroscopy. Both copper (Cu2+) and iron ions (Fe3+) enhanced the radical intensity of both sodium ascorbate and sodium 5,6-benzylidene-L-ascorbate (SBA). Albumin significantly reduced the stimulation effect of copper, but not that of iron. On the other hand, IgG effectively reduced the radical intensity of iron, without affecting that of copper. The present study demonstrates the specific chelating action of these serum proteins, suggesting their possible preventive effects on metal-catalyzed pathogenic diseases.

Adult↗

PubMedDate not supplied

Comparative study of the antitumor action between sodium 5,6-benzylidene-L-ascorbate and sodium ascorbate (minireview).

This review summarizes our comparative study of the antitumor action of sodium 5,6-benzylidene-L-ascorbate (SBA) and sodium ascorbate. Both SBA and ascorbate produced ascorbate radicals during decomposition, elevated oxidation potential and oxidized methionine to methionine sulfoxide, in the regular culture medium. They induced apoptotic cell death (characterized by internucleosomal DNA fragmentation) in human myelogenous leukemic cell lines, but killed most of other tumor cell lines by necrosis without induction of internucleosomal DNA fragmentation. The cytotoxic activity of SBA and ascorbate was significantly enhanced in the presence of copper and the stimulation effect of copper was reduced by a heavy metal antagonist. However, the cytotoxic activity of SBA was only slightly modified by iron, cysteine analog or catalase, in contrast to ascorbate, which was highly sensitive to all these agents. Furthermore, intravenous administration of SBA induced degeneration in chemically-induced hepatocellular carcinoma whereas ascorbate was inactive. These data suggest the differential mode of antitumor action between these two compounds.

Animals↗

PubMedDate not supplied

Effect of physiological fluids on radical intensity of sodium ascorbate and sodium 5,6-benzylidene-L-ascorbate.

The effect of various physiological fluids on the radical intensity of sodium ascorbate and sodium 5,6-benzylidene-L-ascorbate (SBA) was investigated using ESR spectroscopy. Blood from various animals did not significantly affect the radical intensity of both ascorbates, whereas the corresponding plasma fractions significantly enhanced the radical intensity. This suggests that some populations of blood cells might modify the interaction between plasma components and ascorbates. Saliva contained labile substance(s) which effectively reduced the ascorbate radical intensity. HPLC demonstrated the presence of endogenous ascorbate in rat liver and brain homogenates. When sodium ascorbate or SBA was incubated with any of these homogenates, their radical intensity was synergistically enhanced, but abruptly declined without any apparent ascorbate degradation. Incubation with homogenates elevated the radical intensity of SBA up to the level significantly higher than that of sodium ascorbate. The present data suggest that antitumor action of SBA might be mediated via the accelerated production of ascorbate radical in the target organ.

Animals↗

PubMedDate not supplied

Interaction between eugenol-related compounds and radicals.

The radical modulating activity of 2-methoxy-4-(2-propenyl)phenol (eugenol), 2-t-butyl-4-methoxy-phenol (BHA), and their dimers (bis-eugenol, bis-BHA) was investigated, using ESR spectroscopy. Eugenol produced radicals in alkaline solutions, and enhanced the radical intensity of both sodium-L-ascorbate and sodium 5,6-benzylidene-L-ascorbate. BHA has similar, but slightly lower activity, and their dimers were inactive. Their ability to scavenge the superoxide anion (O2-), generated by hypoxanthine and xanthine oxidase reaction, was in the order of eugenol > bis-eugenol > BHA > bis-BHA. The relative radical intensity among these compounds was paralleled by their cytotoxic activity. The present study demonstrates that eugenol and BHA were very reactive with radicals and their reactivity was considerably reduced by dimerization. The applicability of the dimerized eugenol in dentistry was discussed.

Ascorbic Acid↗

PubMedDate not supplied

Role of hydrogen peroxide for cell death induction by sodium 5,6-benzylidene-L-ascorbate.

The role of hydrogen peroxide in the induction of cell death in human promyelocytic leukemic HL-60 cells by sodium 5,6-benzylidene-L-ascorbate (SBA) and its degradation product, ascorbic acid, was investigated. Millimolar concentrations of these compounds induced cell death, characterized by cell shrinkage, nuclear and internucleosomal DNA fragmentation, disappearance of microvilli and condensation of chromatin near the nuclear membrane. Catalase significantly reduced the cytotoxic activity of these compounds, whereas superoxide dismutase, nitric oxide (NO) generator, NO scavenger and NO synthase inhibitor were inactive, suggesting the possible role of H2O2. Determination of H2O2 with the peroxyoxalate chemiluminescence demonstrated that sodium ascorbate and SBA produced H2O2 in amounts necessary for cell death induction.

Antineoplastic Agents↗

PubMedDate not supplied

Role of hydrogen peroxide in antitumor activity induction by sodium 5,6-benzylidene-L-ascorbate.

Role of hydrogen peroxide (H2O2) in the induction of antitumor activity against chemically-induced rat hepatocellular carcinoma by sodium 5,6-benzylidene-L-ascorbate (SBA) was investigated. ESR spectroscopy demonstrated that rat liver homogenate of cancerous tissue significantly enhanced the radical intensity of SBA more potently than that of precancerous or normal tissue. The peroxyoxalate chemiluminescence method demonstrated that SBA significantly enhanced the production of H2O2-derived chemiluminescence intensity in the liver homogenates, and the effect of SBA was greater in cancerous tissue than in precancerous or normal tissue. Addition of ascorbic acid, a degradation product of SBA, showed similar but slightly weaker stimulation effects. These data suggest that antitumor activity of SBA in vivo might, at least in part, be due to H2O2 production.

Animals↗

PubMedDate not supplied

Interaction between sodium 5,6-benzylidene-L-ascorbate and dopamine.

The interaction between sodium 5,6-benzylidene-L-ascorbate (SBA) and dopamine was investigated by three different parameters: radical intensity, prooxidant action and cytotoxic activity. Under alkaline conditions, SBA and dopamine produced doublet and quartet ESR signals, respectively. The addition of increasing concentrations of SBA completely scavenged the dopamine radical and replaced the latter with its own radical. On the other hand, dopamine accelerated the decay of SBA radical. These two compounds stimulated the methionine oxidation in culture medium, but in combination, their stimulation activities were weakened. Both of these two compounds dose-dependently reduced the viable cell number of human promyelocytic leukemics HL-60 cells. When these two compounds were mixed together before adding to HL-60 cells, both of their cytotoxic activities were diminished. The present study demonstrates the interaction between SBA and dopamine, which might modify their biological activities.

Antineoplastic Agents↗