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P Reddanna - One of the best experts on this subject based on the ideXlab platform.

  • betanin a betacyanin pigment purified from fruits of opuntia ficus indica induces apoptosis in human chronic myeloid Leukemia Cell Line k562
    Phytomedicine, 2007
    Co-Authors: Devalraju Sreekanth, M K Arunasree, Karnati R Roy, Chandramohan T Reddy, Gorla V Reddy, P Reddanna
    Abstract:

    Abstract Betalains are water-soluble nitrogenous vacuolar pigments present in flowers and fruits of many caryophyllales with potent antioxidant properties. In the present study the antiproliferative effects of betanin, a principle betacyanin pigment, isolated from the fruits of Opuntia ficus-indica, was evaluated on human chronic myeloid Leukemia Cell Line (K562). The results show dose and time dependent decrease in the proliferation of K562 Cells treated with betanin with an IC50 of 40 μM. Further studies involving scanning and transmission electron microscopy revealed the apoptotic characteristics such as chromatin condensation, Cell shrinkage and membrane blebbing. Agarose electrophoresis of genomic DNA of Cells treated with betanin showed fragmentation pattern typical for apoptotic Cells. Flow cytometric analysis of Cells treated with 40 μM betanin showed 28.4% of Cells in sub G0/G1 phase. Betanin treatment to the Cells also induced the release of cytochrome c into the cytosol, poly (ADP) ribose polymerase (PARP) cleavage, down regulation Bcl-2, and reduction in the membrane potentials. Confocal microscopic studies on the Cells treated with betanin suggest the entry of betanin into the Cells. These studies thus demonstrate that betanin induces apoptosis in K562 Cells through the intrinsic pathway and is mediated by the release of cytochrome c from mitochondria into the cytosol, and PARP cleavage. The antiproliferative effects of betanin add further value to the nutritional characteristics of the fruits of O. ficus-indica.

  • effect of 15 lipoxygenase metabolites 15 s hpete and 15 s hete on chronic myelogenous Leukemia Cell Line k 562 reactive oxygen species ros mediate caspase dependent apoptosis
    Biochemical Pharmacology, 2007
    Co-Authors: Suraneni V K Mahipal, Jagu Subhashini, Madhava C Reddy, Metukuri Mallikarjuna Reddy, Karnati R Roy, Gorla V Reddy, Kotha Anilkumar, P Reddanna
    Abstract:

    Abstract Growth inhibitory effects of 15-lipoxygenase-1 [13-( S )-HPODE and 13-( S )-HODE] and 15-lipoxygenase-2 [15-( S )-HPETE and 15-( S )-HETE] (15-LOX-1 and LOX-2) metabolites and the underlying mechanisms were studied on chronic myeloid Leukemia Cell Line (K-562). The hydroperoxy metabolites, 15-( S )-HPETE and 13-( S )-HPODE rapidly inhibited the growth of K-562 Cells by 3 h with IC 50 values, 10 and 15 μM, respectively. In contrast, the hydroxy metabolite of 15-LOX-2, 15-( S )-HETE, showed 50% inhibition only at 40 μM by 6 h and 13-( S )-HODE, hydroxy metabolite of 15-LOX-1, showed no significant effect up to 160 μM. The Cells exposed to 10 μM of 15-( S )-HPETE and 40 μM of 15-( S )-HETE showed typical apoptotic features like release of cytochrome c , caspase-3 activation and PARP-1 (poly(ADP) ribose polymerase-1) cleavage. A flow cytometry based DCFH-DA analysis and inhibitory studies with DPI, a pharmacological inhibitor of NADPH oxidase, NAC ( N -acetyl cysteine) and GSH revealed that NADPH oxidase-mediated generation of ROS is responsible for caspase-3 activation and subsequent induction of apoptosis in the K-562 Cell Line.

  • molecular mechanisms in c phycocyanin induced apoptosis in human chronic myeloid Leukemia Cell Line k562
    Biochemical Pharmacology, 2004
    Co-Authors: Jagu Subhashini, Suraneni V K Mahipal, Madhava C Reddy, Metukuri Mallikarjuna Reddy, Aparna Rachamallu, P Reddanna
    Abstract:

    Abstract C-Phycocyanin (C-PC), the major light harvesting biliprotein from Spirulina platensis is of greater importance because of its various biological and pharmacological properties. It is a water soluble, non-toxic fluorescent protein pigment with potent anti-oxidant, anti-inflammatory and anti-cancer properties. In the present study the effect of highly purified C-PC was tested on growth and multiplication of human chronic myeloid Leukemia Cell Line (K562). The results indicate significant decrease (49%) in the proliferation of K562 Cells treated with 50 μM C-PC up to 48 h. Further studies involving fluorescence and electron microscope revealed characteristic apoptotic features like Cell shrinkage, membrane blebbing and nuclear condensation. Agarose electrophoresis of genomic DNA of Cells treated with C-PC showed fragmentation pattern typical for apoptotic Cells. Flow cytometric analysis of Cells treated with 25 and 50 μM C-PC for 48 h showed 14.11 and 20.93% Cells in sub-G0/G1 phase, respectively. C-PC treatment of K562 Cells also resulted in release of cytochrome c into the cytosol and poly(ADP) ribose polymerase (PARP) cleavage. These studies also showed down regulation of anti-apoptotic Bcl-2 but without any changes in pro-apoptotic Bax and thereby tilting the Bcl-2/Bax ratio towards apoptosis. These effects of C-PC appear to be mediated through entry of C-PC into the cytosol by an unknown mechanism. The present study thus demonstrates that C-PC induces apoptosis in K562 Cells by cytochrome c release from mitochondria into the cytosol, PARP cleavage and down regulation of Bcl-2.

Yoshio Kanayama - One of the best experts on this subject based on the ideXlab platform.

  • activating mutations of the c kit proto oncogene in a human mast Cell Leukemia Cell Line
    Leukemia, 1994
    Co-Authors: Yuzuru Kanakura, Takuma Furitsu, Hirokazu Ikeda, Tohru Tsujimura, Leonie K. Ashman, Hitoshi Kitayama, Joseph H. Butterfield, Yoshio Kanayama, Yuji Matsuzawa, Yukihiko Kitamura
    Abstract:

    The c-kit proto-oncogene encodes a receptor tyrosine kinase that is known to play a crucial role in mast Cell growth and differentiation. In a human mast Cell Leukemia Cell Line (HMC-1), KitR was found to be constitutively phosphorylated on tyrosine, activated and associated with phosphatidylinositol 3-kinase (P13K) in the absence of autocrine production of SCF. Sequencing of c-kit cDNA revealed that c-kit genes of HMC-1 Cells were composed of a normal, wild-type allele and a mutant allele with two point mutations in codon 560 and codon 816, resulting in intraCellular amino acid substitutions of Gly-560 for Val and Val-816 for Asp, respectively. Murine c-kit mutants encoding Gly-559 and/or Val-814, corresponding to human Gly-560 and/or Val-816, were constructed by site-directed mutagenesis and expressed in Cells of a human embryonic kidney Cell Line (293T). In the transfected Cells, KitR (Gly-559 + Val-814) and KitR (Val-814) were strikingly phosphorylated on tyrosine and activated in the absence of SCF, whereas tyrosine phosphorylation and activation of KitR (Gly-559) or wild-type KitR was modest or little, respectively. These results suggest that constitutive activation of KitR in HMC-1 results from the activating mutations of c-kit gene, and raise the possibility that the activating mutations, particularly at codon 814 of murine c-kit or at codon 816 of human c-kit, may participate in oncogenesis of mast Cells.

  • identification of mutations in the coding sequence of the proto oncogene c kit in a human mast Cell Leukemia Cell Line causing ligand independent activation of c kit product
    Journal of Clinical Investigation, 1993
    Co-Authors: Takuma Furitsu, Uichi Koshimizu, Hirokazu Ikeda, Hiroyuki Sugahara, Tohru Tsujimura, Leonie K. Ashman, Hitoshi Kitayama, Joseph H. Butterfield, Tatsuhito Tono-oka, Yoshio Kanayama
    Abstract:

    Abstract The c-kit proto-oncogene encodes a receptor tyrosine kinase. Binding of c-kit ligand, stem Cell factor (SCF) to c-kit receptor (c-kitR) is known to activate c-kitR tyrosine kinase, thereby leading to autophosphorylation of c-kitR on tyrosine and to association of c-kitR with substrates such as phosphatidylinositol 3-kinase (PI3K). In a human mast Cell Leukemia Cell Line HMC-1, c-kitR was found to be constitutively phosphorylated on tyrosine, activated, and associated with PI3K without the addition of SCF. The expression of SCF mRNA transcript in HMC-1 Cells was not detectable by means of PCR after reverse transcription (RT-PCR) analysis, suggesting that the constitutive activation of c-kitR was ligand independent. Sequencing of whole coding region of c-kit cDNA revealed that c-kit genes of HMC-1 Cells were composed of a normal, wild-type allele and a mutant allele with two point mutations resulting in intraCellular amino acid substitutions of Gly-560 for Val and Val-816 for Asp. Amino acid sequences in the regions of the two mutations are completely conserved in all of mouse, rat, and human c-kit. In order to determine the causal role of these mutations in the constitutive activation, murine c-kit mutants encoding Gly-559 and/or Val-814, corresponding to human Gly-560 and/or Val-816, were constructed by site-directed mutagenesis and expressed in a human embryonic kidney Cell Line, 293T Cells. In the transfected Cells, both c-kitR (Gly-559, Val-814) and c-kitR (Val-814) were abundantly phosphorylated on tyrosine and activated in immune complex kinase reaction in the absence of SCF, whereas tyrosine phosphorylation and activation of c-kitR (Gly-559) or wild-type c-kitR was modest or little, respectively. These results suggest that conversion of Asp-816 to Val in human c-kitR may be an activating mutation and responsible for the constitutive activation of c-kitR in HMC-1 Cells.

Leila Chekirghedira - One of the best experts on this subject based on the ideXlab platform.

  • isorhamnetin 3 o robinobioside from nitraria retusa leaves enhance antioxidant and antigenotoxic activity in human chronic myelogenous Leukemia Cell Line k562
    BMC Complementary and Alternative Medicine, 2012
    Co-Authors: Jihed Boubaker, Mohammed Ben Sghaier, Ines Skandrani, Kamel Ghedira, Leila Chekirghedira
    Abstract:

    In this report, the isorhamnetin 3-o-robinobioside and its original extract, the ethyl acetate extract, from Nitraria retusa leaves, were evaluated for their ability to induce antioxidant and antigenotoxic effects in human chronic myelogenous Leukemia Cell Line. Nitraria retusa products properties were carried out by firstly evaluating their effects against lipid peroxidation induced by H2O2, using the thiobarbituric acid reactive substances species (TBARS) assay, and proceeding to the assay of Cellular antioxidant activity, then doing the comet assay. The isorhamnetin 3-o-robinobioside showed a protective effect against lipid peroxidation induced by H2O2. The same natural compound and ethyl acetate extract inhibited oxidation induced by 2,2′-azobis (2-amidinopropane) dihydrochloride in human chronic myelogenous Leukemia Cells with respectively 50% inhibitory concentration values of 0.225 mg/ml and 0.31 mg/ml, reflecting a significant antioxidant potential. The same two products inhibited the genotoxicity induced by hydroxyl radicals in the same human Cell Line (by 77.77% at a concentration of 800 μg/ml and by 80.55% at a concentration of 1000 μg/ml respectively). The i sorhamnetin 3- o-robinobioside and its original extract, the ethyl acetate extract, from Nitraria retusa leaves, have a great antioxidant and antigenotoxic potential on human chronic myelogenous Leukemia Cell Line K562.

Jagu Subhashini - One of the best experts on this subject based on the ideXlab platform.

  • effect of 15 lipoxygenase metabolites 15 s hpete and 15 s hete on chronic myelogenous Leukemia Cell Line k 562 reactive oxygen species ros mediate caspase dependent apoptosis
    Biochemical Pharmacology, 2007
    Co-Authors: Suraneni V K Mahipal, Jagu Subhashini, Madhava C Reddy, Metukuri Mallikarjuna Reddy, Karnati R Roy, Gorla V Reddy, Kotha Anilkumar, P Reddanna
    Abstract:

    Abstract Growth inhibitory effects of 15-lipoxygenase-1 [13-( S )-HPODE and 13-( S )-HODE] and 15-lipoxygenase-2 [15-( S )-HPETE and 15-( S )-HETE] (15-LOX-1 and LOX-2) metabolites and the underlying mechanisms were studied on chronic myeloid Leukemia Cell Line (K-562). The hydroperoxy metabolites, 15-( S )-HPETE and 13-( S )-HPODE rapidly inhibited the growth of K-562 Cells by 3 h with IC 50 values, 10 and 15 μM, respectively. In contrast, the hydroxy metabolite of 15-LOX-2, 15-( S )-HETE, showed 50% inhibition only at 40 μM by 6 h and 13-( S )-HODE, hydroxy metabolite of 15-LOX-1, showed no significant effect up to 160 μM. The Cells exposed to 10 μM of 15-( S )-HPETE and 40 μM of 15-( S )-HETE showed typical apoptotic features like release of cytochrome c , caspase-3 activation and PARP-1 (poly(ADP) ribose polymerase-1) cleavage. A flow cytometry based DCFH-DA analysis and inhibitory studies with DPI, a pharmacological inhibitor of NADPH oxidase, NAC ( N -acetyl cysteine) and GSH revealed that NADPH oxidase-mediated generation of ROS is responsible for caspase-3 activation and subsequent induction of apoptosis in the K-562 Cell Line.

  • molecular mechanisms in c phycocyanin induced apoptosis in human chronic myeloid Leukemia Cell Line k562
    Biochemical Pharmacology, 2004
    Co-Authors: Jagu Subhashini, Suraneni V K Mahipal, Madhava C Reddy, Metukuri Mallikarjuna Reddy, Aparna Rachamallu, P Reddanna
    Abstract:

    Abstract C-Phycocyanin (C-PC), the major light harvesting biliprotein from Spirulina platensis is of greater importance because of its various biological and pharmacological properties. It is a water soluble, non-toxic fluorescent protein pigment with potent anti-oxidant, anti-inflammatory and anti-cancer properties. In the present study the effect of highly purified C-PC was tested on growth and multiplication of human chronic myeloid Leukemia Cell Line (K562). The results indicate significant decrease (49%) in the proliferation of K562 Cells treated with 50 μM C-PC up to 48 h. Further studies involving fluorescence and electron microscope revealed characteristic apoptotic features like Cell shrinkage, membrane blebbing and nuclear condensation. Agarose electrophoresis of genomic DNA of Cells treated with C-PC showed fragmentation pattern typical for apoptotic Cells. Flow cytometric analysis of Cells treated with 25 and 50 μM C-PC for 48 h showed 14.11 and 20.93% Cells in sub-G0/G1 phase, respectively. C-PC treatment of K562 Cells also resulted in release of cytochrome c into the cytosol and poly(ADP) ribose polymerase (PARP) cleavage. These studies also showed down regulation of anti-apoptotic Bcl-2 but without any changes in pro-apoptotic Bax and thereby tilting the Bcl-2/Bax ratio towards apoptosis. These effects of C-PC appear to be mediated through entry of C-PC into the cytosol by an unknown mechanism. The present study thus demonstrates that C-PC induces apoptosis in K562 Cells by cytochrome c release from mitochondria into the cytosol, PARP cleavage and down regulation of Bcl-2.

Takuma Furitsu - One of the best experts on this subject based on the ideXlab platform.

  • activating mutations of the c kit proto oncogene in a human mast Cell Leukemia Cell Line
    Leukemia, 1994
    Co-Authors: Yuzuru Kanakura, Takuma Furitsu, Hirokazu Ikeda, Tohru Tsujimura, Leonie K. Ashman, Hitoshi Kitayama, Joseph H. Butterfield, Yoshio Kanayama, Yuji Matsuzawa, Yukihiko Kitamura
    Abstract:

    The c-kit proto-oncogene encodes a receptor tyrosine kinase that is known to play a crucial role in mast Cell growth and differentiation. In a human mast Cell Leukemia Cell Line (HMC-1), KitR was found to be constitutively phosphorylated on tyrosine, activated and associated with phosphatidylinositol 3-kinase (P13K) in the absence of autocrine production of SCF. Sequencing of c-kit cDNA revealed that c-kit genes of HMC-1 Cells were composed of a normal, wild-type allele and a mutant allele with two point mutations in codon 560 and codon 816, resulting in intraCellular amino acid substitutions of Gly-560 for Val and Val-816 for Asp, respectively. Murine c-kit mutants encoding Gly-559 and/or Val-814, corresponding to human Gly-560 and/or Val-816, were constructed by site-directed mutagenesis and expressed in Cells of a human embryonic kidney Cell Line (293T). In the transfected Cells, KitR (Gly-559 + Val-814) and KitR (Val-814) were strikingly phosphorylated on tyrosine and activated in the absence of SCF, whereas tyrosine phosphorylation and activation of KitR (Gly-559) or wild-type KitR was modest or little, respectively. These results suggest that constitutive activation of KitR in HMC-1 results from the activating mutations of c-kit gene, and raise the possibility that the activating mutations, particularly at codon 814 of murine c-kit or at codon 816 of human c-kit, may participate in oncogenesis of mast Cells.

  • identification of mutations in the coding sequence of the proto oncogene c kit in a human mast Cell Leukemia Cell Line causing ligand independent activation of c kit product
    Journal of Clinical Investigation, 1993
    Co-Authors: Takuma Furitsu, Uichi Koshimizu, Hirokazu Ikeda, Hiroyuki Sugahara, Tohru Tsujimura, Leonie K. Ashman, Hitoshi Kitayama, Joseph H. Butterfield, Tatsuhito Tono-oka, Yoshio Kanayama
    Abstract:

    Abstract The c-kit proto-oncogene encodes a receptor tyrosine kinase. Binding of c-kit ligand, stem Cell factor (SCF) to c-kit receptor (c-kitR) is known to activate c-kitR tyrosine kinase, thereby leading to autophosphorylation of c-kitR on tyrosine and to association of c-kitR with substrates such as phosphatidylinositol 3-kinase (PI3K). In a human mast Cell Leukemia Cell Line HMC-1, c-kitR was found to be constitutively phosphorylated on tyrosine, activated, and associated with PI3K without the addition of SCF. The expression of SCF mRNA transcript in HMC-1 Cells was not detectable by means of PCR after reverse transcription (RT-PCR) analysis, suggesting that the constitutive activation of c-kitR was ligand independent. Sequencing of whole coding region of c-kit cDNA revealed that c-kit genes of HMC-1 Cells were composed of a normal, wild-type allele and a mutant allele with two point mutations resulting in intraCellular amino acid substitutions of Gly-560 for Val and Val-816 for Asp. Amino acid sequences in the regions of the two mutations are completely conserved in all of mouse, rat, and human c-kit. In order to determine the causal role of these mutations in the constitutive activation, murine c-kit mutants encoding Gly-559 and/or Val-814, corresponding to human Gly-560 and/or Val-816, were constructed by site-directed mutagenesis and expressed in a human embryonic kidney Cell Line, 293T Cells. In the transfected Cells, both c-kitR (Gly-559, Val-814) and c-kitR (Val-814) were abundantly phosphorylated on tyrosine and activated in immune complex kinase reaction in the absence of SCF, whereas tyrosine phosphorylation and activation of c-kitR (Gly-559) or wild-type c-kitR was modest or little, respectively. These results suggest that conversion of Asp-816 to Val in human c-kitR may be an activating mutation and responsible for the constitutive activation of c-kitR in HMC-1 Cells.