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ABSTRACT: Cotylenin A, a plant growth regulator, and rapa-mycin, an inhibitor of the mammalian target of rapamycin, are potent inducers of differentiation in myeloid leukemia cells and also synergistically inhibit the proliferation of several human breast cancer cell lines including MCF-7 in vitro and in vivo. However, the mechanisms of the combined effects of cotylenin A and rapamycin are still unknown. Activated Akt induced by rapamycin has been suggested to attenuate the growth-inhibitory effects of rapamycin, serving as a negative feedback mechanism. In this study, we found that cotylenin A could suppress rapamycin-induced phosphorylation of Akt (Ser473) in MCF-7 cells and lung carcinoma A549 cells and that cotylenin A also enhanced the rapamycin-induced growth inhibition of MCF-7 and A549 cells. ISIR-005 (a synthetic cotylenin A-derivative) was able to enhance rapamycin‑induced growth inhibition and could also markedly inhibit rapamycin-induced phosphorylation of Akt. We also found that the HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) or arsenic trioxide (ATO) in combination with rapamycin markedly inhibited the growth of MCF-7 cells and 17-AAG or ATO suppressed rapamycin-induced phosphorylation of Akt. The PI3K inhibitor LY294002 also suppressed rapamycin-induced phosphorylation of Akt and combined treatment showed synergistic growth inhibition of MCF-7 cells. Rapamycin inhibited growth more significantly in Akt siRNA-transfected MCF-7 cells than in control siRNA-transfected MCF-7 cells. These results suggest that the inhibition of rapamycin-induced Akt phosphorylation by cotylenin A correlates with their effective growth inhibition of cancer cells.
International Journal of Oncology 12/2012; · 2.40 Impact Factor
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ABSTRACT: Hypoxia has been shown to promote metastasis of cancer cells through induction of epithelial-mesenchymal transition (EMT). It is also known to cause generation of reactive oxygen species (ROS). We investigated here the role of ROS in hypoxia-induced EMT and whether attenuation of ROS by antioxidants suppresses hypoxia-induced EMT and metastasis of human pancreatic cancer cells in a xenograft nude mouse model. PANC-1 and MiaPaCa-2 cells exposed to hypoxia (1 % O(2)) showed increased ROS generation and characteristic changes of EMT such as morphological changes, enhanced invasiveness, and upregulation of EMT regulators, SLUG, SNAI1 and TWIST. The antioxidants N-acetylcysteine (NAC) and ebselen significantly suppressed EMT and the expression of EMT regulators during hypoxia. NAC abrogated activation of HIF-1α and NF-κB, both of which were found to play an active role in hypoxia-induced EMT. Administration of NAC to nude mice with orthotopic tumors suppressed the expression of EMT regulators in hypoxic areas and significantly inhibited hepatic metastasis. Together, the present findings demonstrate that attenuation of ROS by antioxidants suppresses hypoxia-induced EMT and metastatic phenotype, suggesting that antioxidants may be of therapeutic value in treating pancreatic cancers.
Clinical and Experimental Metastasis 07/2012; · 3.52 Impact Factor
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Koshi Kawakami,
Miho Hattori,
Takatsugu Inoue,
Yuriko Maruyama,
Junko Ohkanda,
Nobuo Kato,
Miki Tongu,
Takaya Yamada,
Miho Akimoto,
Keizo Takenaga,
Takeshi Sassa,
Junji Suzumiy, Yoshio Honma
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ABSTRACT: Malignant cells in solid tumors survive under prolonged hypoxia and can be a source of resistance to current cancer therapies. Tumor hypoxia is also associated with a more malignant phenotype and poor survival in cancer patients. Recent progress in our understanding of the biology of tumor cells under hypoxia has led to increased attention on targeting hypoxia for cancer therapy. We report here that a novel fusicoccin derivative (ISIR-042), but not its parent or related compounds such as fusicoccin A and cotylenin A, is more cytotoxic to hypoxic cells than to normoxic cells. The hypoxia-induced accumulation of hypoxia-inducible factor (HIF)-1α and the phosphorylation of Akt were effectively inhibited by treatment with ISIR-042, suggesting that the preferential cytotoxicity toward hypoxic cells is associated with a reduction of HIF-1α and Akt activation. ISIR-042 inhibited the growth of human pancreatic cancer MIAPaCa-2 cells while sparing normal endothelial cells, and significantly inhibited the growth of MIAPaCa-2 cells as xenografts without apparent adverse effects. Pancreatic cancer cells expressing CD24 and CD44 exhibited characteristics of stem cells. Treatment with gemcitabine increased this stem cell-enriched population, and this effect was significantly inhibited by ISIR-042, suggesting that ISIR- 042 preferentially inhibits stem/progenitors in pancreatic cancer cell lines compared with chemotherapeutic agents. These results suggest that ISIR-042 may be a potential therapeutic agent for hypoxic tumors such as pancreatic cancer.
Anti-cancer agents in medicinal chemistry 01/2012; 12(7):791-800.
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ABSTRACT: Cyclopamine, a plant-derived steroidal alkaloid, inhibits the hedgehog (Hh) signaling pathway by antagonizing Smoothened. This drug can induce the differentiation of myeloid leukemia cell lines and acute myeloid leukemia (AML) cells in primary culture. The treated cells were stained with Luxol-fast-blue, which is specific for eosinophilic granules. Ligation of CD44 with some specific monoclonal antibodies can reverse the differentiation of AML cells. Combined treatment with cyclopamine and a monoclonal antibody to ligate CD44 more than additively induced the differentiation of HL-60 cells. These results may provide useful information for the development of a CD44-targeted therapy in AML.
Leukemia research 10/2010; 35(5):638-45. · 2.36 Impact Factor
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Nippon rinsho. Japanese journal of clinical medicine 07/2010; 68 Suppl 7:134-6.
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ABSTRACT: An elevated serum level of NM23-H1 protein is found in acute myelogenous leukemia (AML) and predicts a poor treatment outcome for AML patients. To investigate the potential pathological link between the elevated serum level of this protein and poor prognosis, we examined the extracellular effects of recombinant NM23-H1 protein on the in vitro survival of primary cultured normal peripheral blood mononuclear cells (PBMNC) at concentrations equivalent to the levels found in the serum of AML patients. Extracellular NM23-H1 protein inhibited the in vitro survival of PBMNC and promoted the production of various cytokines, such as GM-CSF and IL-1beta, which in fact promoted the growth of primary cultured AML cells. These findings indicate a novel biological action of extracellular NM23-H1 and its association with poor prognosis of patients with elevated serum levels of NM23-H1 protein. These results suggest an important role of extracellular NM23-H1 in the malignant progression of leukemia and a potential therapeutic target for these malignancies.
International journal of hematology 09/2009; 90(2):143-52. · 1.17 Impact Factor
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ABSTRACT: An elevated serum level of NM23-H1 protein is found in acute myelogenous leukemia (AML), and predicts a poor treatment outcome in AML patients. To investigate the potential pathological link between the elevated serum level of this protein and poor prognosis, we examined the extracellular effects of recombinant NM23-H1 protein on the in vitro growth and survival of primary cultured AML cells at concentrations equivalent to the levels found in the serum of AML patients. Extracellular NM23-H1 protein promoted the in vitro growth and survival of AML cells and this activity was associated with the cytokine production and activation of the MAPK and signal transducers and activators of transcription signaling pathways. Inhibitors specific to MAPK signaling pathways inhibited the growth- and survival-promoting activity of NM23-H1. These findings indicate the novel biological action of extracellular NM23-H1 and its association with poor prognosis, and suggest an important role for extracellular NM23-H1 in the malignant progression of leukemia and a potential therapeutic target for these malignancies.
Cancer Science 08/2009; 100(10):1885-94. · 3.33 Impact Factor
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ABSTRACT: Cotylenin A, a plant growth regulator, and rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), are potent inducers of differentiation of myeloid leukemia cells. Recently, we found that cotylenin A and rapamycin effectively inhibited the proliferation of several human breast cancer cell lines including MCF-7. Herein, we demonstrate that cotylenin A and rapamycin rapidly and markedly induced the cyclin G2 gene expression in several cancer cells including MCF-7 cells. The growth arrest of the MCF-7 cells at the G1 phase, induced by the treatment with cotylenin A and rapamycin or the culture in low serum medium, markedly induced the cyclin G2 gene expression. Anticancer drugs including doxorubicin, etoposide and 5-fluorouracil also induced cyclin G2 expression during induction of growth arrest of the MCF-7 cell at the G1 phase or G2/M phase. Ectopically inducible cyclin G2 expression potently inhibited the proliferation of MCF-7 cells. Furthermore, cyclin G2 knockdown induced by cyclin G2 small interfering RNA markedly reduced the potency of cotylenin A plus rapamycin to induce growth inhibition. Taken together, our results suggest that cotylenin A and rapamycin induce inhibition of cancer cell growth through the induction of cyclin G2.
Cancer Science 09/2008; 99(8):1693-8. · 3.33 Impact Factor
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ABSTRACT: Lithocholic acid (LCA) acetate induced the differentiation of human leukemia cells. Treatment with a combination of LCA acetate and cotylenin A, an inducer of the differentiation of leukemia cells, was more effective than that with LCA acetate or cotylenin A alone at inducing monocytic differentiation. LCA acetate activated mitogen-activated protein kinase (MAPK) before inducing differentiation. Cotylenin A did not activate MAPK, suggesting that cotylenin A has a different mode of action. The cooperative effects of LCA acetate and cotylenin A on inducing differentiation were, at least partly, due to the enhancement of LCA acetate-induced MAPK activation by cotylenin A.
Leukemia Research 08/2008; 32(7):1112-23. · 2.92 Impact Factor
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ABSTRACT: Mutations in mitochondrial DNA (mtDNA) occur at high frequency in human tumors, but whether these mutations alter tumor cell behavior has been unclear. We used cytoplasmic hybrid (cybrid) technology to replace the endogenous mtDNA in a mouse tumor cell line that was poorly metastatic with mtDNA from a cell line that was highly metastatic, and vice versa. Using assays of metastasis in mice, we found that the recipient tumor cells acquired the metastatic potential of the transferred mtDNA. The mtDNA conferring high metastatic potential contained G13997A and 13885insC mutations in the gene encoding NADH (reduced form of nicotinamide adenine dinucleotide) dehydrogenase subunit 6 (ND6). These mutations produced a deficiency in respiratory complex I activity and were associated with overproduction of reactive oxygen species (ROS). Pretreatment of the highly metastatic tumor cells with ROS scavengers suppressed their metastatic potential in mice. These results indicate that mtDNA mutations can contribute to tumor progression by enhancing the metastatic potential of tumor cells.
Science 06/2008; 320(5876):661-4. · 31.20 Impact Factor
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ABSTRACT: A low concentration of differentiation inducers greatly enhances the in vitro and in vivo antiproliferative effects of interferon (IFN)alpha in several human cancer cells. Among the differentiation inducers tested, the sensitivity of cancer cells to IFNalpha was most strongly affected by cotylenin A. Cotylenin A, which is a novel fusicoccane diterpene glycoside with a complex sugar moiety, affected the differentiation of leukemia cells that were freshly isolated from acute myelogenous leukemia patients in primary culture. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptor DR5 were early genes induced by the combination of cotylenin A and IFNalpha in carcinoma cells. Neutralizing antibody to TRAIL inhibited apoptosis, suggesting that cotylenin A and IFNalpha cooperatively induced apoptosis through the TRAIL signaling system. Combined treatment preferentially induced apoptosis in human lung cancer cells while sparing normal lung epithelial cells. In an analysis of various cancer cell lines, ovarian cancer cells were highly sensitive to combined treatment with cotylenin A and IFNalpha in terms of the inhibition of cell growth. This treatment was also effective toward ovarian cancer cells that were refractory to cisplatin, and significantly inhibited the growth of ovarian cancer cells as xenografts without apparent adverse effects. Ovarian cancer cells from patients were also sensitive to the combined treatment in primary cultures. Combined treatment with cotylenin A and IFNalpha may have therapeutic value in treating human cancers including ovarian cancer.
Cancer Science 12/2007; 98(11):1643-51. · 3.33 Impact Factor
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ABSTRACT: Cotylenin A, which has been isolated as a plant growth regulator, potently induces the differentiation of human myeloid leukemia cells. Treatment of HL-60 cells with a combination of transforming growth factor (TGF)-beta and 1alpha, 25-dihydroxyvitamin D(3) (VD3) resulted in increased differentiation compared to separate treatments, but TGF-beta did not affect the cotylenin A-induced differentiation of HL-60 cells. It is possible that the signal transduction pathway used by cotylenin A for inducing the differentiation of leukemia cells is the same as that used by TGF-beta. However, cotylenin A did not affect the expression of TGF superfamily or Smad genes in HL-60 cells. Treatment with neutralizing anti-TGF-beta antibody or an inhibitor of TGF-beta signaling did not inhibit cotylenin A-induced differentiation, although VD3-induced differentiation was significantly suppressed by these treatments. The subcellular distribution of Smad3 was also unaffected by cotylenin A. These results suggest that the cotylenin A-induced differentiation of leukemia cells is independent of the TGF-beta signaling system, although TGF-beta acts as an autocrine mediator of the growth arrest and differentiation of leukemia cells induced by VD3 and other inducers.
Leukemia and Lymphoma 05/2006; 47(4):733-40. · 2.58 Impact Factor
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ABSTRACT: Recently, we found that cotylenin A and IFNalpha synergistically inhibited growth both in vitro and in vivo, and induced apoptosis in human cancer cells. For the clinical application of this combined treatment, suitable cancer targets should be selected.
We examined the combined effects of these compounds on various types of cancer cells by a human cancer cell line panel assay, and on cancer cells that had been freshly isolated from patients in three-dimensional cultures embedded in collagen gel.
In the analysis of 39 cancer cell lines, ovarian cancer cells were highly sensitive to combined treatment with cotylenin A and IFNalpha in inhibiting cell growth. This treatment was also effective toward ovarian cancer cells that were refractory to CDDP, and significantly inhibited the growth of ovarian cancer cells as xenografts without apparent adverse effects. Ovarian cancer cells from the patients were also sensitive to the combined treatment in primary cultures.
Combined treatment with cotylenin A and IFNalpha may have therapeutic value in treating ovarian cancer.
Gynecologic Oncology 01/2006; 99(3):680-8. · 3.89 Impact Factor
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ABSTRACT: We have previously reported that NM23 genes are overexpressed in various hematological malignancies and that serum NM23-H1 protein levels are useful for predicting patient outcomes. In this study we assessed the clinical implications of serum NM23-H1 protein on neuroblastoma. We examined serum NM23-H1 protein levels in 217 patients with neuroblastoma, including 131 found by mass-screening and 86 found clinically by an enzyme-linked immunosorbent assay, and determined the association between levels of this protein, and known prognostic factors or the clinical outcome. The serum NM23-H1 protein level was higher in neuroblastoma patients than in control children (P < 0.0001). Patients with MYCN amplification had higher serum NM23-H1 levels than those with a single copy of MYCN. Overall survival was assessed in the 86 patients found clinically, and was found to be worse in patients with higher serum MN23-H1 levels (> or = 250 ng/mL) than in those with lower levels (< 250 ng/mL; P = 0.034). The higher level of NM23-H1 was correlated with a worse outcome in patients with a single MYCN copy, or in those younger than 12 months of age. Serum NM23-H1 protein levels may contribute to predictions of clinical outcome in patients with neuroblastoma.
Cancer Science 11/2005; 96(10):653-60. · 3.33 Impact Factor
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ABSTRACT: Cytokinins are important purine derivatives that act as redifferentiation-inducing hormones to control many processes in plants. Cytokinins such as isopentenyladenine (IPA) and kinetin are very effective at inducing the granulocytic differentiation of human myeloid leukemia HL-60 cells. We examined the gene expression profiles associated with exposure to IPA using cDNA microarrays and compared the results with those obtained with other inducers of differentiation, such as all-trans retinoic acid (ATRA), 1 alpha,25-dihydroxyvitamin D3 (VD3) and cotylenin A (CN-A). Many genes were up-regulated, and only a small fraction were down-regulated, upon exposure to the inducers. IPA and CN-A, but not ATRA or VD3, immediately induced the expression of mRNA for the calcium-binding protein S100P. The up-regulation of S100P was confirmed at the protein expression level. We also examined the expression of other S100 proteins, including S100A8, S100A9 and S100A12, and found that IPA preferentially up-regulated S100P at the early stages of differentiation. IPA-induced differentiation of HL-60 cells was suppressed by treatment with antisense oligonucleotides against S100P, suggesting that S100P plays an important role in cell differentiation.
Biochimica et Biophysica Acta 10/2005; 1745(2):156-65. · 4.66 Impact Factor
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Yoshio Honma
Nippon rinsho. Japanese journal of clinical medicine 09/2005; 63 Suppl 8:123-4.
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ABSTRACT: The interaction of granulocyte-colony stimulating factor (G-CSF) and retinoic acid (RA) in proliferation and differentiation of acute promyelocytic leukemia (APL) cells was examined. G-CSF stimulated proliferation of APL cells at concentrations of 0.1 to 50 ng/ml in a dose dependent manner. More than 10−8M RA induced granulocytic differentiation of APL cells. Although G-CSF induced lysozyme activities in APL cells, it alone did not induce terminal differentiation of APL cells. G-CSF significantly enhanced the RA-induced granulocytic differentiation of APL cells in vitro. Enhancement by G-CSF was not due to the prolongation of survival of RA-induced differentiated cells, but the differentiation-inducing effects of G-CSF might be evident only in the presence of RA. Since G-CSF has a potential to induce the granulocytic differentiation of myeloid leukemia cells, G-CSF in combination with RA may be applicable in differentiation induction therapy for some types of myeloid leukemia.
Cancer Science 08/2005; 80(11):1077 - 1082. · 3.33 Impact Factor
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ABSTRACT: Recent studies showed high frequencies of homoplasmic mtDNA mutations in various human tumor types, suggesting that the mutated mtDNA haplotypes somehow contribute to expression of tumor phenotypes. We directly addressed this issue by isolating mouse mtDNA-less (rho(0)) cells for complete mtDNA replacement between normal cells and their carcinogen-induced transformants, and examined the effect of the mtDNA replacement on expression of tumorigenicity, a phenotype forming tumors in nude mice. The results showed that genome chimera cells carrying nuclear DNA from tumor cells and mtDNA from normal cells expressed tumorigenicity, whereas those carrying nuclear DNA from normal cells and mtDNA from tumor cells did not. These observations provided direct evidence that nuclear DNA, but not mtDNA, is responsible for carcinogen-induced malignant transformation, although it remains possible that mtDNA mutations and resultant respiration defects may influence the degree of malignancy, such as invasive or metastatic properties.
Biochemical and Biophysical Research Communications 03/2005; 327(4):1028-35. · 2.48 Impact Factor
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ABSTRACT: Cytokinins, purine derivatives that act as hormones to control many processes in plants, are very effective at inducing the granulocytic differentiation of human myeloid leukaemia cells. Isopentenyladenine (IPA), a potent cytokinin, significantly induced the expression of CCAAT/enhancer-binding protein (C/EBP)delta, but not C/EBP alpha protein, whereas all-trans retinoic acid, a well-known inducer of granulocytic differentiation, induced C/EBP alpha but not C/EBP delta protein. Antisense oligonucleotide for C/EBP delta, but not C/EBP alpha or C/EBP beta, effectively suppressed IPA-induced differentiation, suggesting that the expression of C/EBP delta protein is necessary for cytokinin-induced differentiation. Although C/EBP alpha is known to be crucial for granulocytic differentiation, the function of C/EBP delta has not been well documented in the regulation of haematopoiesis. The role of C/EBP delta in the granulocytic differentiation of myeloid leukaemia cells is discussed.
British Journal of Haematology 03/2005; 128(4):540-7. · 4.94 Impact Factor
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ABSTRACT: Several clones of dexamethasone-resistant cells, which could not differentiate even in a high concentration of dexamethasone, were isolated from glucocorticoid-sensitive myeloid leukemic cells. Some of them were shown to be deficient in steroid binding to specific cytoplasmic receptors, while the others contained glucocorticoid-specific cytoplasmic receptors that might be the same as those in sensitive cells. One of the resistant clones was found to be almost completely deficient in nuclear acceptor sites for cytoplasmic steroid-receptor complexes. The remaining clones were also characterized by significantly reduced amounts of nuclear-bound glucocorticoid. These results suggest that resistibility to glucocorticoids in the resistant clones of myeloid leukemic cells is due mainly to a defect in some steps of intracellular transfer of the steroid. Dexamethasone-sensitive cells, which could differentiate in the presence of dexamethasone, could be also induced to differentiate by protein factor(s) in ascitic fluid. Although all the resistant cells showed a low response to ascitic fluid, some of them showed 10-fold enhancement of phagocytic activity which is a typical character of differentiated cells. These results suggest that response to steroids is not directly correlated with that to protein inducer(s).
Journal of Cellular Physiology 02/2005; 93(2):227 - 235. · 3.87 Impact Factor
