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Isao Matsuiyuasa - One of the best experts on this subject based on the ideXlab platform.
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mechanism of growth inhibitory effect of cape aloe extract in ehrlich Ascites Tumor cells
Journal of Nutritional Science and Vitaminology, 2007Co-Authors: Saeda Kametani, Akiko Kojimayuasa, David Opare Kennedy, Mayumi Honzawa, Tomoko Oikawa, Toshio Norikura, Isao MatsuiyuasaAbstract:Cape aloe (Aloe ferox Miller) has been a herb well known for its cathartic properties and has also been used popularly as a health drink (juice, tea and tonic) in the United States and in Europe. Cape aloe extract also has been reported to possess several pharmacological effects, such as anti-inflammatory, anti-bacterial, anti-fungal and protective effect against liver injury. However, the investigations on an anti-Tumor activity in cape aloe extract are very few and subsequent mechanisms have not been well elucidated. In this study, we examined the effect of the selective growth inhibitory activity of cape aloe extract and found that the cape aloe extract, especially the dichloromethane (CH2Cl2) extract, caused a dose-dependent growth inhibitory effect in Ehrlich Ascites Tumor cells (EATC), but not in mouse embryo fibroblast (NIH3T3) cells, which was used as a normal cell model. Furthermore, the CH2Cl2 extract caused an accumulation of cells in the G1 phase and a decrease of cells in the S and G2/M phase of the cell cycle and inhibited DNA synthesis in a dose-dependent manner. In addition, other results suggest that cell cycle arrest and inhibition of proliferation in EATC by the CH2Cl2 extract are associated with decreased retinoblastoma protein (Rb) phosphorylation.
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chemical constituents of cape aloe and their synergistic growth inhibiting effect on ehrlich Ascites Tumor cells
Bioscience Biotechnology and Biochemistry, 2007Co-Authors: Akiko Kojimayuasa, David Opare Kennedy, Saeda Kametani, Hiroe Kikuzaki, Mayumi Honzawa, Isao MatsuiyuasaAbstract:The constituents of cape aloe were investigated after a preliminary screening of the growth-inhibiting effect on Ehrlich Ascites Tumor cells (EATC) of several extracts of this plant. Ten compounds were isolated from the dichloromethane (CH2Cl2) extract that showed the strongest activity, and their structures were elucidated as aloe-emodin (1), p-hydroxybenzaldehyde (2), p-hydroxyacetophenone (3), pyrocatechol (4), 10-oxooctadecanoic acid (5), 10-hydroxyoctadecanoic acid (6), methyl 10-hydroxyoctadecanoate (7), 7-hydroxy-2,5-dimethylchromone (8), furoaloesone (9), and 2-acetonyl-8-(2-furoylmethyl)-7-hydroxy-5-methylchromone (10) based on MS and various NMR spectroscopic techniques. Compounds 2–7 were isolated for the first time from cape aloe. Compounds 4–7 and 10 showed a significant growth-inhibiting effect, and compound 1 exhibited a remarkable synergistic effect on compounds 8–10, which was not observed with the treatment by each compound alone on EATC. These results suggest that the strong growth-inhi...
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chemical constituents of cape aloe and their synergistic growth inhibiting effect on ehrlich Ascites Tumor cells
Bioscience Biotechnology and Biochemistry, 2007Co-Authors: Akiko Kojimayuasa, David Opare Kennedy, Saeda Kametani, Hiroe Kikuzaki, Mayumi Honzawa, Isao MatsuiyuasaAbstract:The constituents of cape aloe were investigated after a preliminary screening of the growth-inhibiting effect on Ehrlich Ascites Tumor cells (EATC) of several extracts of this plant. Ten compounds were isolated from the dichloromethane (CH(2)Cl(2)) extract that showed the strongest activity, and their structures were elucidated as aloe-emodin (1), p-hydroxybenzaldehyde (2), p-hydroxyacetophenone (3), pyrocatechol (4), 10-oxooctadecanoic acid (5), 10-hydroxyoctadecanoic acid (6), methyl 10-hydroxyoctadecanoate (7), 7-hydroxy-2,5-dimethylchromone (8), furoaloesone (9), and 2-acetonyl-8-(2-furoylmethyl)-7-hydroxy-5-methylchromone (10) based on MS and various NMR spectroscopic techniques. Compounds 2-7 were isolated for the first time from cape aloe. Compounds 4-7 and 10 showed a significant growth-inhibiting effect, and compound 1 exhibited a remarkable synergistic effect on compounds 8-10, which was not observed with the treatment by each compound alone on EATC. These results suggest that the strong growth-inhibiting effect of the CH(2)Cl(2) extract was dependent not on one compound alone, but on the synergistic effect from the combination of compound 1 and the other compounds.
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involvement of polyamines in evening primrose extract induced apoptosis in ehrlich Ascites Tumor cells
Amino Acids, 2005Co-Authors: Tsutomu Arimura, Akiko Kojimayuasa, Y Tatsumi, David Opare Kennedy, Isao MatsuiyuasaAbstract:We previously demonstrated that evening primrose extract (EPE) induced apoptosis and inhibited the DNA synthesis in Ehrlich Ascites Tumor cells (EATC) and suggested that EPE-induced inhibition of the growth of EATC are via at least two pathway differentially modulated by reactive oxygen species, notably intracellular peroxides. These are (a) the EPE-induced apoptosis pathway which is dependent on increases in hydrogen peroxide and (b) the EPE-induced inhibition of cell proliferation which is hydrogen peroxide independent. In this study, EPE brought about a significant decrease in intracellular polyamine levels. Furthermore, the addition of polyamines reversed the EPE-induced decrease in cell viability and suppressed the EPE-induced increase in intracellular hydrogen peroxides. However, the addition of polyamines did not reverse EPE-induced decrease in DNA synthesis and phosphorylation of Rb protein, and EPE-induced translocation of AIF. These results suggest the involvement of polyamines in the EPE-induced apoptosis pathway which is dependent on increase in hydrogen peroxide.
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caspase independent apoptosis induced by evening primrose extract in ehrlich Ascites Tumor cells
Cancer Letters, 2003Co-Authors: Tsutomu Arimura, Akiko Kojimayuasa, David Opare Kennedy, Mayu Suzuki, Isao MatsuiyuasaAbstract:We previously demonstrated that evening primrose extract (EPE) induced apoptosis in Ehrlich Ascites Tumor cells, while mouse embryo fibroblast cells (NIH3T3) used as a normal cell model, showed no effect of cell viability by treatment of EPE. Furthermore, our results demonstrated the rapid increase in intracellular peroxides levels, loss of mitochondrial membrane potential and the release of cytochrome c to cytosol, suggesting that the rapid increase in intracellular peroxides levels after addition of EPE triggers off induction of apoptosis. In this study, we identified that EPE elicited the translocation of Bax to mitochondria and apoptosis-inducing factor (AIF) to nuclei, but no activation of caspase-3-like protease. We also demonstrated that the rapid EPE-induced increase in hydrogen peroxide levels caused the translocation of Bax to mitochondria, and then mitochondrial cytochrome c was released. One of the main consequences of mitochondrial cytochrome c release is the activation of caspase-3. However, no caspase-3 activation was observed. On the other hand, AIF was translocated from mitochondria to nuclei. The EPE-induced translocation of AIF was suppressed with the addition of catalase, suggesting that the rapid intracellular peroxide levels after addition of EPE triggers off induction of apoptosis, which is AIF-mediated and caspase-independent.
David Opare Kennedy - One of the best experts on this subject based on the ideXlab platform.
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mechanism of growth inhibitory effect of cape aloe extract in ehrlich Ascites Tumor cells
Journal of Nutritional Science and Vitaminology, 2007Co-Authors: Saeda Kametani, Akiko Kojimayuasa, David Opare Kennedy, Mayumi Honzawa, Tomoko Oikawa, Toshio Norikura, Isao MatsuiyuasaAbstract:Cape aloe (Aloe ferox Miller) has been a herb well known for its cathartic properties and has also been used popularly as a health drink (juice, tea and tonic) in the United States and in Europe. Cape aloe extract also has been reported to possess several pharmacological effects, such as anti-inflammatory, anti-bacterial, anti-fungal and protective effect against liver injury. However, the investigations on an anti-Tumor activity in cape aloe extract are very few and subsequent mechanisms have not been well elucidated. In this study, we examined the effect of the selective growth inhibitory activity of cape aloe extract and found that the cape aloe extract, especially the dichloromethane (CH2Cl2) extract, caused a dose-dependent growth inhibitory effect in Ehrlich Ascites Tumor cells (EATC), but not in mouse embryo fibroblast (NIH3T3) cells, which was used as a normal cell model. Furthermore, the CH2Cl2 extract caused an accumulation of cells in the G1 phase and a decrease of cells in the S and G2/M phase of the cell cycle and inhibited DNA synthesis in a dose-dependent manner. In addition, other results suggest that cell cycle arrest and inhibition of proliferation in EATC by the CH2Cl2 extract are associated with decreased retinoblastoma protein (Rb) phosphorylation.
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chemical constituents of cape aloe and their synergistic growth inhibiting effect on ehrlich Ascites Tumor cells
Bioscience Biotechnology and Biochemistry, 2007Co-Authors: Akiko Kojimayuasa, David Opare Kennedy, Saeda Kametani, Hiroe Kikuzaki, Mayumi Honzawa, Isao MatsuiyuasaAbstract:The constituents of cape aloe were investigated after a preliminary screening of the growth-inhibiting effect on Ehrlich Ascites Tumor cells (EATC) of several extracts of this plant. Ten compounds were isolated from the dichloromethane (CH2Cl2) extract that showed the strongest activity, and their structures were elucidated as aloe-emodin (1), p-hydroxybenzaldehyde (2), p-hydroxyacetophenone (3), pyrocatechol (4), 10-oxooctadecanoic acid (5), 10-hydroxyoctadecanoic acid (6), methyl 10-hydroxyoctadecanoate (7), 7-hydroxy-2,5-dimethylchromone (8), furoaloesone (9), and 2-acetonyl-8-(2-furoylmethyl)-7-hydroxy-5-methylchromone (10) based on MS and various NMR spectroscopic techniques. Compounds 2–7 were isolated for the first time from cape aloe. Compounds 4–7 and 10 showed a significant growth-inhibiting effect, and compound 1 exhibited a remarkable synergistic effect on compounds 8–10, which was not observed with the treatment by each compound alone on EATC. These results suggest that the strong growth-inhi...
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chemical constituents of cape aloe and their synergistic growth inhibiting effect on ehrlich Ascites Tumor cells
Bioscience Biotechnology and Biochemistry, 2007Co-Authors: Akiko Kojimayuasa, David Opare Kennedy, Saeda Kametani, Hiroe Kikuzaki, Mayumi Honzawa, Isao MatsuiyuasaAbstract:The constituents of cape aloe were investigated after a preliminary screening of the growth-inhibiting effect on Ehrlich Ascites Tumor cells (EATC) of several extracts of this plant. Ten compounds were isolated from the dichloromethane (CH(2)Cl(2)) extract that showed the strongest activity, and their structures were elucidated as aloe-emodin (1), p-hydroxybenzaldehyde (2), p-hydroxyacetophenone (3), pyrocatechol (4), 10-oxooctadecanoic acid (5), 10-hydroxyoctadecanoic acid (6), methyl 10-hydroxyoctadecanoate (7), 7-hydroxy-2,5-dimethylchromone (8), furoaloesone (9), and 2-acetonyl-8-(2-furoylmethyl)-7-hydroxy-5-methylchromone (10) based on MS and various NMR spectroscopic techniques. Compounds 2-7 were isolated for the first time from cape aloe. Compounds 4-7 and 10 showed a significant growth-inhibiting effect, and compound 1 exhibited a remarkable synergistic effect on compounds 8-10, which was not observed with the treatment by each compound alone on EATC. These results suggest that the strong growth-inhibiting effect of the CH(2)Cl(2) extract was dependent not on one compound alone, but on the synergistic effect from the combination of compound 1 and the other compounds.
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involvement of polyamines in evening primrose extract induced apoptosis in ehrlich Ascites Tumor cells
Amino Acids, 2005Co-Authors: Tsutomu Arimura, Akiko Kojimayuasa, Y Tatsumi, David Opare Kennedy, Isao MatsuiyuasaAbstract:We previously demonstrated that evening primrose extract (EPE) induced apoptosis and inhibited the DNA synthesis in Ehrlich Ascites Tumor cells (EATC) and suggested that EPE-induced inhibition of the growth of EATC are via at least two pathway differentially modulated by reactive oxygen species, notably intracellular peroxides. These are (a) the EPE-induced apoptosis pathway which is dependent on increases in hydrogen peroxide and (b) the EPE-induced inhibition of cell proliferation which is hydrogen peroxide independent. In this study, EPE brought about a significant decrease in intracellular polyamine levels. Furthermore, the addition of polyamines reversed the EPE-induced decrease in cell viability and suppressed the EPE-induced increase in intracellular hydrogen peroxides. However, the addition of polyamines did not reverse EPE-induced decrease in DNA synthesis and phosphorylation of Rb protein, and EPE-induced translocation of AIF. These results suggest the involvement of polyamines in the EPE-induced apoptosis pathway which is dependent on increase in hydrogen peroxide.
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caspase independent apoptosis induced by evening primrose extract in ehrlich Ascites Tumor cells
Cancer Letters, 2003Co-Authors: Tsutomu Arimura, Akiko Kojimayuasa, David Opare Kennedy, Mayu Suzuki, Isao MatsuiyuasaAbstract:We previously demonstrated that evening primrose extract (EPE) induced apoptosis in Ehrlich Ascites Tumor cells, while mouse embryo fibroblast cells (NIH3T3) used as a normal cell model, showed no effect of cell viability by treatment of EPE. Furthermore, our results demonstrated the rapid increase in intracellular peroxides levels, loss of mitochondrial membrane potential and the release of cytochrome c to cytosol, suggesting that the rapid increase in intracellular peroxides levels after addition of EPE triggers off induction of apoptosis. In this study, we identified that EPE elicited the translocation of Bax to mitochondria and apoptosis-inducing factor (AIF) to nuclei, but no activation of caspase-3-like protease. We also demonstrated that the rapid EPE-induced increase in hydrogen peroxide levels caused the translocation of Bax to mitochondria, and then mitochondrial cytochrome c was released. One of the main consequences of mitochondrial cytochrome c release is the activation of caspase-3. However, no caspase-3 activation was observed. On the other hand, AIF was translocated from mitochondria to nuclei. The EPE-induced translocation of AIF was suppressed with the addition of catalase, suggesting that the rapid intracellular peroxide levels after addition of EPE triggers off induction of apoptosis, which is AIF-mediated and caspase-independent.
Venkateswara R Naraparaju - One of the best experts on this subject based on the ideXlab platform.
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antiTumor effect of vitamin d binding protein derived macrophage activating factor on ehrlich Ascites Tumor bearing mice
Experimental Biology and Medicine, 1999Co-Authors: Yoshihiko Koga, Venkateswara R Naraparaju, Nobuto YamamotoAbstract:Cancerous cells secrete alpha-N-acetylgalactosaminidase (NaGalase) into the blood stream, resulting in deglycosylation of serum vitamin D3-binding protein (known as Gc protein), which is a precursor for macrophage activating factor (MAF). Incubation of Gc protein with immobilized beta-galactosidase and sialidase generates the most potent macrophage activating factor (designated GcMAF). Administration of GcMAF to cancer-bearing hosts can bypass the inactivated MAF precursor and act directly on macrophages for efficient activation. Therapeutic effects of GcMAF on Ehrlich Ascites Tumor-bearing mice were assessed by survival time and serum NaGalase activity, because serum NaGalase activity was proportional to Tumor burden. A single administration of GcMAF (100 pg/mouse) to eight mice on the same day after transplantation of the Tumor (5 x 10(5) cells) showed a mean survival time of 21 +/- 3 days for seven mice, with one mouse surviving more than 60 days, whereas Tumor-bearing controls had a mean survival time of 13 +/- 2 days. Six of the eight mice that received two GcMAF administrations, at Day 0 and Day 4 after transplantation, survived up to 31 +/- 4 days whereas, the remaining two mice survived for more than 60 days. Further, six of the eight mice that received three GcMAF administrations with 4-day intervals showed an extended survival of at least 60 days, and serum NaGalase levels were as low as those of control mice throughout the survival period. The cure with subthreshold GcMAF-treatments (administered once or twice) of Tumor-bearing mice appeared to be a consequence of sustained macrophage activation by inflammation resulting from the macrophage-mediated Tumoricidal process. Therefore, a protracted macrophage activation induced by a few administrations of minute amounts of GcMAF eradicated the murine Ascites Tumor.
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immunotherapy of balb c mice bearing ehrlich Ascites Tumor with vitamin d binding protein derived macrophage activating factor
Cancer Research, 1997Co-Authors: Nobuto Yamamoto, Venkateswara R NaraparajuAbstract:Abstract Vitamin D3-binding protein (DBP; human DBP is known as Gc protein) is the precursor of macrophage activating factor (MAF). Treatment of mouse DBP with immobilized β-galactosidase or treatment of human Gc protein with immobilized β-galactosidase and sialidase generated a remarkably potent MAF, termed DBPMAF or GcMAF, respectively. The domain of Gc protein responsible for macrophage activation was cloned and enzymatically converted to the cloned MAF, designated CdMAF. In Ehrlich Ascites Tumor-bearing mice, Tumor-specific serum α-N-acetylgalactosaminidase (NaGalase) activity increased linearly with time as the transplanted Tumor cells grew in the peritoneal cavity. Therapeutic effects of DBPMAF, GcMAF, and CdMAF on mice bearing Ehrlich Ascites Tumor were assessed by survival time, the total Tumor cell count in the peritoneal cavity, and serum NaGalase activity. Mice that received a single administration of DBPMAF or GcMAF (100 pg/mouse) on the same day after transplantation of Tumor (1 × 105 cells) showed a mean survival time of 35 ± 4 days, whereas Tumor-bearing controls had a mean survival time of 16 ± 2 days. When mice received the second DBPMAF or GcMAF administration at day 4, they survived more than 50 days. Mice that received two DBPMAF administrations, at days 4 and 8 after transplantation of 1 × 105 Tumor cells, survived up to 32 ± 4 days. At day 4 posttransplantation, the total Tumor cell count in the peritoneal cavity was approximately 5 × 105 cells. Mice that received two DBPMAF administrations, at days 0 and 4 after transplantation of 5 × 105 Tumor cells, also survived up to 32 ± 4 days, while control mice that received the 5 × 105 Ascites Tumor cells only survived for 14 ± 2 days. Four DBPMAF, GcMAF, or CdMAF administrations to mice transplanted with 5 × 105 Ehrlich Ascites Tumor cells with 4-day intervals showed an extended survival of at least 90 days and an insignificantly low serum NaGalase level between days 30 and 90.
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immunotherapy of balb c mice bearing ehrlich Ascites Tumor with vitamin d binding protein derived macrophage activating factor
Cancer Research, 1997Co-Authors: Nobuto Yamamoto, Venkateswara R NaraparajuAbstract:Vitamin D3-binding protein (DBP; human DBP is known as Gc protein) is the precursor of macrophage activating factor (MAF). Treatment of mouse DBP with immobilized beta-galactosidase or treatment of human Gc protein with immobilized beta-galactosidase and sialidase generated a remarkably potent MAF, termed DBPMAF or GcMAF, respectively. The domain of Gc protein responsible for macrophage activation was cloned and enzymatically converted to the cloned MAF, designated CdMAF. In Ehrlich Ascites Tumor-bearing mice, Tumor-specific serum alpha-N-acetylgalactosaminidase (NaGalase) activity increased linearly with time as the transplanted Tumor cells grew in the peritoneal cavity. Therapeutic effects of DBPMAF, GcMAF, and CdMAF on mice bearing Ehrlich Ascites Tumor were assessed by survival time, the total Tumor cell count in the peritoneal cavity, and serum NaGalase activity. Mice that received a single administration of DBPMAF or GcMAF (100 pg/mouse) on the same day after transplantation of Tumor (1 x 10(5) cells) showed a mean survival time of 35 +/- 4 days, whereas Tumor-bearing controls had a mean survival time of 16 +/- 2 days. When mice received the second DBPMAF or GcMAF administration at day 4, they survived more than 50 days. Mice that received two DBPMAF administrations, at days 4 and 8 after transplantation of 1 x 10(5) Tumor cells, survived up to 32 +/- 4 days. At day 4 posttransplantation, the total Tumor cell count in the peritoneal cavity was approximately 5 x 10(5) cells. Mice that received two DBPMAF administrations, at days 0 and 4 after transplantation of 5 x 10(5) Tumor cells, also survived up to 32 +/- 4 days, while control mice that received the 5 x 10(5) Ascites Tumor cells only survived for 14 +/- 2 days. Four DBPMAF, GcMAF, or CdMAF administrations to mice transplanted with 5 x 10(5) Ehrlich Ascites Tumor cells with 4-day intervals showed an extended survival of at least 90 days and an insignificantly low serum NaGalase level between days 30 and 90.
Else K Hoffmann - One of the best experts on this subject based on the ideXlab platform.
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separate swelling and ca2 activated anion currents in ehrlich Ascites Tumor cells
The Journal of Membrane Biology, 1998Co-Authors: Stine F Pedersen, Else K Hoffmann, Jean Prenen, Guillaume Droogmans, Bernd NiliusAbstract:A Ca2+-activated (ICl,Ca) and a swelling-activated anion current (ICl,vol) were investigated in Ehrlich Ascites Tumor cells using the whole cell patch clamp technique. Large, outwardly rectifying currents were activated by an increase in the free intracellular calcium concentration ([Ca2+]i), or by hypotonic exposure of the cells, respectively. The reversal potential of both currents was dependent on the extracellular Cl- concentration. ICl,Ca current density increased with increasing [Ca2+]i, and this current was abolished by lowering [Ca2+]i to Cl- > gluconate. ICl,Ca was inhibited by niflumic acid (100 micron), 5-Nitro-2-(3-phenylpropylamino)benzoic acid (NPPB, 100 micron) and 4, 4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS, 100 micron), niflumic acid being the most potent inhibitor. In contrast, ICl,vol was unaffected by niflumic acid (100 micron), but abolished by tamoxifen (10 micron). Thus, in Ehrlich cells, separate chloride currents, ICl,Ca and ICl,vol, are activated by an increase in [Ca2+]i and by cell swelling, respectively.
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ph regulation in sensitive and multidrug resistant ehrlich Ascites Tumor cells
Cellular Physiology and Biochemistry, 1998Co-Authors: Thomas Litman, Torben Skovsgaard, Stine F Pedersen, Birte Kramhoft, Else K HoffmannAbstract:Maintenance and regulation of intracellular pH (pHi) was studied in wild-type Ehrlich Ascites Tumor cells (EHR2) and five progressively daunorubicin-resistant, P-glycoprotein (P-gp)-expressing strains, the maximally resistant of which is EHR2/1.3. Steady-state pHi was similar in cells expressing different amounts of P-gp, in the absence and presence of glucose. In EHR2/1.3, glucose-induced acidification was reduced, and proton efflux was increased, compared to the wild-type EHR2, differences which were not caused by increased activity of a Na+/H+ exchanger in the resistant cells. Comparing all six cell lines, no evidence was found for a correlation between the amount of P-gp in the membrane and pHi regulation, which was also unaffected by P-gp modulators. However, a correlation was seen between relative resistance/daunorubicin accumulation and acid extrusion rate, which is likely to be due to aspects of development of drug resistance other than P-gp.
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activation of protein kinase c during cell volume regulation in ehrlich mouse Ascites Tumor cells
Biochimica et Biophysica Acta, 1994Co-Authors: Anna Kirstine Larsen, Bo Skaaning Jensen, Else K HoffmannAbstract:Abstract We have previously demonstrated that in Ehrlich cells a bumetanide-sensitive Na+,K+,2Cl− cotransporter is activated during regulatory volume decrease after cell shrinkage (hypertonic conditions) as well as during the late phase of regulatory volume decrease (hypotonic conditions). It is, however, quiescent under isotonic conditions. Using a protein kinase C assay system (Amersham, UK) it is here demonstrated that hypertonic cell shrinkage results in an increase in protein kinase C activity to 174% within the first minute, concomitant with the activation of the Na+,K+,2Cl− cotransporter. Hypotonic cell swelling results in a late activation of protein kinase C concomitant with a late activation of the Na+,K+,2Cl− cotransporter. The activation of protein kinase C during hypertonic as well as hypotonic conditions is inhibited by H-7. The more specific protein kinase C inhibitor chelerythrine inhibited protein kinase C as well as the Na+,K+,2Cl− cotransporter to the same extent as did H-7. These results indicate the involvement of protein kinase C in the regulation of the Na+,K+,2Cl− cotransporter in Ehrlich Ascites Tumor cells during cell volume regulation.
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relation between cytoskeleton hypo osmotic treatment and volume regulation in ehrlich Ascites Tumor cells
The Journal of Membrane Biology, 1993Co-Authors: M Cornet, Ian Henry Lambert, Else K HoffmannAbstract:Pretreatment with cytochalasin B, which is known to disrupt microfilaments, significantly inhibits regulatory volume decrease (RVD) in Ehrlich Ascites Tumor cells, suggesting that an intact microfilament network is a prerequisite for a normal RVD response. Colchicine, which is known to disrupt microtubules, has no significant effect on RVD. Ehrlich cells have a cortical three-dimensional, orthogonal F-actin filament network which makes the cells look completely black in light microscopy following immunogold/silver staining using anti-actin antibodies. After addition of cytochalasin B, the stained cells get lighter with black dots localized to the plasma membrane and appearance of multiple knobby protrusions at cell periphery. Also, a significant decrease in the staining of the cells is seen after 15 min of RVD in hypotonic medium. This microfilament reorganization appears during RVD in the presence of external Ca2+ or Ca2+-ionophore A23187. It is, however, abolished in the absence of extracellular calcium, with or without prior depletion of intracellular Ca2+ stores. An effect of increased calcium influx might therefore be considered. The microfilament reorganization during RVD is abolished by the calmodulin antagonists pimozide and trifluoperazine, suggesting the involvement of calmodulin in the process. The microfilament reorganization is also prevented by addition of quinine. This quinine inhibition is overcome by addition of the K+ ionophore valinomycin.
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regulation of taurine transport in ehrlich Ascites Tumor cells
The Journal of Membrane Biology, 1993Co-Authors: Ian Henry Lambert, Else K HoffmannAbstract:Taurine influx is inhibited and taurine efflux accelerated when the cell membrane of Ehrlich Ascites Tumor cells is depolarized. Taurine influx is inhibited at acid pH partly due to the concomitant depolarization of the cell membrane partly due to a reduced availability of negatively charged free carrier. These results are in agreement with a 2Na, 1Cl, 1taurine cotransport system which is sensitive to the membrane potential due to a negatively charged empty carrier. Taurine efflux from Ehrlich cells is stimulated by addition of LTD4 and by swelling in hypotonic medium. Cell swelling in hypotonic medium is known to result in stimulation of the leukotriene synthesis and depolarization of the cell membrane. The taurine efflux, activated by cell swelling, is dramatically reduced when the phospholipase A2 is inhibited indirectly by addition of the anti-calmodulin drug pimozide, or directly by addition of RO 31-4639. The inhibition is in both cases lifted by addition of LTD4. The swelling-induced taurine efflux is also inhibited by addition of the 5-lipoxygenase inhibitors ETH 615-139 and NDGA. It is concluded that the swelling-induced activation of the taurine leak pathway involves a release of arachidonic acid from the membrane phospholipids and an increased oxidation of arachidonic acid into leukotrienes via the 5-lipoxygenase pathway. LTD4 seems to act as a second messenger for the swelling induced activation of the taurine leak pathway either directly or indirectly via its activation of the Cl− channels, i.e., via a depolarization of the cell membrane.
Nobuto Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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antiTumor effect of vitamin d binding protein derived macrophage activating factor on ehrlich Ascites Tumor bearing mice
Experimental Biology and Medicine, 1999Co-Authors: Yoshihiko Koga, Venkateswara R Naraparaju, Nobuto YamamotoAbstract:Cancerous cells secrete alpha-N-acetylgalactosaminidase (NaGalase) into the blood stream, resulting in deglycosylation of serum vitamin D3-binding protein (known as Gc protein), which is a precursor for macrophage activating factor (MAF). Incubation of Gc protein with immobilized beta-galactosidase and sialidase generates the most potent macrophage activating factor (designated GcMAF). Administration of GcMAF to cancer-bearing hosts can bypass the inactivated MAF precursor and act directly on macrophages for efficient activation. Therapeutic effects of GcMAF on Ehrlich Ascites Tumor-bearing mice were assessed by survival time and serum NaGalase activity, because serum NaGalase activity was proportional to Tumor burden. A single administration of GcMAF (100 pg/mouse) to eight mice on the same day after transplantation of the Tumor (5 x 10(5) cells) showed a mean survival time of 21 +/- 3 days for seven mice, with one mouse surviving more than 60 days, whereas Tumor-bearing controls had a mean survival time of 13 +/- 2 days. Six of the eight mice that received two GcMAF administrations, at Day 0 and Day 4 after transplantation, survived up to 31 +/- 4 days whereas, the remaining two mice survived for more than 60 days. Further, six of the eight mice that received three GcMAF administrations with 4-day intervals showed an extended survival of at least 60 days, and serum NaGalase levels were as low as those of control mice throughout the survival period. The cure with subthreshold GcMAF-treatments (administered once or twice) of Tumor-bearing mice appeared to be a consequence of sustained macrophage activation by inflammation resulting from the macrophage-mediated Tumoricidal process. Therefore, a protracted macrophage activation induced by a few administrations of minute amounts of GcMAF eradicated the murine Ascites Tumor.
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immunotherapy of balb c mice bearing ehrlich Ascites Tumor with vitamin d binding protein derived macrophage activating factor
Cancer Research, 1997Co-Authors: Nobuto Yamamoto, Venkateswara R NaraparajuAbstract:Abstract Vitamin D3-binding protein (DBP; human DBP is known as Gc protein) is the precursor of macrophage activating factor (MAF). Treatment of mouse DBP with immobilized β-galactosidase or treatment of human Gc protein with immobilized β-galactosidase and sialidase generated a remarkably potent MAF, termed DBPMAF or GcMAF, respectively. The domain of Gc protein responsible for macrophage activation was cloned and enzymatically converted to the cloned MAF, designated CdMAF. In Ehrlich Ascites Tumor-bearing mice, Tumor-specific serum α-N-acetylgalactosaminidase (NaGalase) activity increased linearly with time as the transplanted Tumor cells grew in the peritoneal cavity. Therapeutic effects of DBPMAF, GcMAF, and CdMAF on mice bearing Ehrlich Ascites Tumor were assessed by survival time, the total Tumor cell count in the peritoneal cavity, and serum NaGalase activity. Mice that received a single administration of DBPMAF or GcMAF (100 pg/mouse) on the same day after transplantation of Tumor (1 × 105 cells) showed a mean survival time of 35 ± 4 days, whereas Tumor-bearing controls had a mean survival time of 16 ± 2 days. When mice received the second DBPMAF or GcMAF administration at day 4, they survived more than 50 days. Mice that received two DBPMAF administrations, at days 4 and 8 after transplantation of 1 × 105 Tumor cells, survived up to 32 ± 4 days. At day 4 posttransplantation, the total Tumor cell count in the peritoneal cavity was approximately 5 × 105 cells. Mice that received two DBPMAF administrations, at days 0 and 4 after transplantation of 5 × 105 Tumor cells, also survived up to 32 ± 4 days, while control mice that received the 5 × 105 Ascites Tumor cells only survived for 14 ± 2 days. Four DBPMAF, GcMAF, or CdMAF administrations to mice transplanted with 5 × 105 Ehrlich Ascites Tumor cells with 4-day intervals showed an extended survival of at least 90 days and an insignificantly low serum NaGalase level between days 30 and 90.
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immunotherapy of balb c mice bearing ehrlich Ascites Tumor with vitamin d binding protein derived macrophage activating factor
Cancer Research, 1997Co-Authors: Nobuto Yamamoto, Venkateswara R NaraparajuAbstract:Vitamin D3-binding protein (DBP; human DBP is known as Gc protein) is the precursor of macrophage activating factor (MAF). Treatment of mouse DBP with immobilized beta-galactosidase or treatment of human Gc protein with immobilized beta-galactosidase and sialidase generated a remarkably potent MAF, termed DBPMAF or GcMAF, respectively. The domain of Gc protein responsible for macrophage activation was cloned and enzymatically converted to the cloned MAF, designated CdMAF. In Ehrlich Ascites Tumor-bearing mice, Tumor-specific serum alpha-N-acetylgalactosaminidase (NaGalase) activity increased linearly with time as the transplanted Tumor cells grew in the peritoneal cavity. Therapeutic effects of DBPMAF, GcMAF, and CdMAF on mice bearing Ehrlich Ascites Tumor were assessed by survival time, the total Tumor cell count in the peritoneal cavity, and serum NaGalase activity. Mice that received a single administration of DBPMAF or GcMAF (100 pg/mouse) on the same day after transplantation of Tumor (1 x 10(5) cells) showed a mean survival time of 35 +/- 4 days, whereas Tumor-bearing controls had a mean survival time of 16 +/- 2 days. When mice received the second DBPMAF or GcMAF administration at day 4, they survived more than 50 days. Mice that received two DBPMAF administrations, at days 4 and 8 after transplantation of 1 x 10(5) Tumor cells, survived up to 32 +/- 4 days. At day 4 posttransplantation, the total Tumor cell count in the peritoneal cavity was approximately 5 x 10(5) cells. Mice that received two DBPMAF administrations, at days 0 and 4 after transplantation of 5 x 10(5) Tumor cells, also survived up to 32 +/- 4 days, while control mice that received the 5 x 10(5) Ascites Tumor cells only survived for 14 +/- 2 days. Four DBPMAF, GcMAF, or CdMAF administrations to mice transplanted with 5 x 10(5) Ehrlich Ascites Tumor cells with 4-day intervals showed an extended survival of at least 90 days and an insignificantly low serum NaGalase level between days 30 and 90.
