5-alpha-reductase: 2012-11-11

2012年11月17日星期六

Mitotic requirement for aurora A kinase is bypassed in the absence of aurora B kinase.

Mitotic requirement for aurora A kinase is bypassed in the absence of aurora B kinase.

FEBS Lett. 2005 Jun 20;579(16):3385-91

Authors: Yang H, Burke T, Dempsey J, Diaz B, Collins E, Toth J, Beckmann R, Ye X

Abstract
We investigated why treatment of cells with dual aurora A and B kinase inhibitors produces phenotypes identical to inactivation of aurora B. We found that dual aurora kinase inhibitors in fact potently inhibit cellular activities of both kinases, indicating that inactivation of aurora B bypasses aurora A in mitosis. RNAi experiments further established that inactivation of aurora B indeed bypasses the requirement for aurora A and leads to polyploidy. Inactivation of aurora A activates checkpoint kinase BubR1 in an aurora B-dependent manner. Our results thus show that aurora B is responsible for mitotic arrest in the absence of aurora A.

PMID: 15922328 [PubMed - indexed for MEDLINE]

dovitinib dna-pk coxinhibitors

Aurora kinase B, epigenetic state of centromeric heterochromatin and chiasma resolution in oocytes.

Aurora kinase B, epigenetic state of centromeric heterochromatin and chiasma resolution in oocytes.

Reprod Biomed Online. 2009 Sep;19(3):352-68

Authors: Vogt E, Kipp A, Eichenlaub-Ritter U

Abstract
Aurora kinases comprise a family of phosphoproteins performing multiple functions in mitosis and meiosis. Because Aurora kinase B (AURKB) expression is altered in aged oocytes and there is only limited information on its function in meiosis, it was decided to study the spatial distribution and co-localization of AURKB with other regulatory proteins at centromeres during mouse oocyte maturation. AURKB associates with chromosomes after germinal vesicle breakdown, is enriched at centromeres from prometaphase I and transits to the spindle midzone at late anaphase I. Preferential inhibition of AURKB by low concentrations of ZM 447439 inhibitor prevents polar body formation and affects spindle formation and chromosome congression at meiosis I, associated with expression of BubR1 checkpoint protein at kinetochores. Release of cohesion between sister chromatids appears inhibited resulting in failure of chiasma resolution in oocytes progressing to anaphase I. Concomitantly, the inhibitor reduces histone H3 lysine 9 trimethylation at centromeric heterochromatin and affects chromosome condensation. The cytokinesis arrest protects young, healthy oocytes from errors in chromosome segregation although increasing polyploidy. This study shows that changes in activity of AURKB may increase risks for chromosome non-disjunction and aneuploidy in mammalian oocytes, irrespective of age.

PMID: 19778480 [PubMed - indexed for MEDLINE]

zm-447439 rad001 ecdysone

Antiproliferative effect of Aurora kinase targeting in mesothelioma.

Antiproliferative effect of Aurora kinase targeting in mesothelioma.

Lung Cancer. 2010 Dec;70(3):271-9

Authors: Crispi S, Fagliarone C, Biroccio A, D'Angelo C, Galati R, Sacchi A, Vincenzi B, Baldi A, Verdina A

Abstract
The Aurora proteins are a small family of serine/threonine kinase that function in various stages of mitosis. Current interest in Aurora kinase relates to its role in tumours, and its potential as a therapeutic target. In this work we studied the expression of Aurora kinases A and B and related genes in human mesothelioma tissues and in five mesothelioma cell lines. Moreover, we analyzed the effects of ZM447439 (ZM), an Aurora kinase inhibitor, on cellular growth. Results evidenced an over-expression of Aurora kinase A and related genes in human mesothelioma tissues and an over-expression of Aurora kinases A and B in all cell lines. Moreover, we demonstrated that ZM447439 was able to inhibit cell growth in all cell lines and that this inhibition was due to a specific effect as demonstrated by the reduction in the level of Histone H3 phosphorylation. Our findings support a role of Aurora kinase in mesothelioma and the possibility of using Aurora kinase inhibitors in therapeutic modalities.

PMID: 20371132 [PubMed - indexed for MEDLINE]

c-met inhibitors zm-447439 rad001

MAPK interacts with XGef and is required for CPEB activation during meiosis in Xenopus oocytes.

MAPK interacts with XGef and is required for CPEB activation during meiosis in Xenopus oocytes.

J Cell Sci. 2007 Mar 15;120(Pt 6):1093-103

Authors: Keady BT, Kuo P, Mart�nez SE, Yuan L, Hake LE

Abstract
Meiotic progression in Xenopus oocytes, and all other oocytes investigated, is dependent on polyadenylation-induced translation of stockpiled maternal mRNAs. Early during meiotic resumption, phosphorylation of CPE-binding protein (CPEB) is required for polyadenylation-induced translation of mRNAs encoding cell cycle regulators. Xenopus Gef (XGef), a Rho-family guanine-exchange factor, influences the activating phosphorylation of CPEB. An exchange-deficient version of XGef does not, therefore implicating Rho-family GTPase function in early meiosis. We show here that Clostridium difficile Toxin B, a Rho-family GTPase inhibitor, does not impair early CPEB phosphorylation or progression to germinal vesicle breakdown, indicating that XGef does not influence these events through activation of a Toxin-B-sensitive GTPase. Using the inhibitors U0126 for mitogen-activated protein kinase (MAPK), and ZM447439 for Aurora kinase A and Aurora kinase B, we found that MAPK is required for phosphorylation of CPEB, whereas Aurora kinases are not. Furthermore, we do not detect active Aurora kinase A in early meiosis. By contrast, we observe an early, transient activation of MAPK, independent of Mos protein expression. MAPK directly phosphorylates CPEB on four residues (T22, T164, S184, S248), but not on S174, a key residue for activating CPEB function. Notably, XGef immunoprecipitates contain MAPK, and this complex can phosphorylate CPEB. MAPK may prime CPEB for phosphorylation on S174 by an as-yet-unidentified kinase or may activate this kinase.

PMID: 17344432 [PubMed - indexed for MEDLINE]

rad001 ecdysone chir-258

Development of focal adhesion kinase inhibitors in cancer therapy.

Development of focal adhesion kinase inhibitors in cancer therapy.

Anticancer Agents Med Chem. 2011 Sep;11(7):638-42

Authors: Ma WW

Abstract
Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase implicated in cancer progression, and plays a vital role in integrating environmental signals from growth factors, extracellular matrix and mechanical forces. As a scaffolding protein, FAK interacts and regulates the activity of many signaling kinases including Src, VEGFR-3, p53, PI3k and IGF-1R. In turn, FAK activity is modulated by a complex network of regulators that presents a number of therapeutic approaches to targeting FAK in cancer therapy. The ATP competitive inhibitors binds directly to FAK kinase domain to abrogate multiple downstream signaling pathways, and this class of agents lead the way in FAK inhibitor clinical development. CFAK-C4 and Y15 represents a novel class of non-ATP dependant, allosteric inhibitors that interrupt protein-protein interactions to achieve anti-cancer effects. The optimal approach to targeting FAK for cancer therapy is currently under investigation. Preliminary efficacy signals from early-phase trials suggest that FAK inhibitors may be best used in combination therapy. In addition to determining dosing schedules that is tolerable by patients, future clinical studies should include mechanistic-based pharmacodynamic studies to determine the biological active dose and explore potential predictive markers. In summary, a rich pipeline of FAK-targeting agents is entering clinical development and has the potential of improving the lives of cancer patients.

PMID: 21787276 [PubMed - indexed for MEDLINE]

coxinhibitors c-met inhibitors zm-447439

2012年11月16日星期五

The Ipl1/Aurora kinase family: methods of inhibition and functional analysis in mammalian cells.

The Ipl1/Aurora kinase family: methods of inhibition and functional analysis in mammalian cells.

Methods Mol Biol. 2005;296:371-81

Authors: Ditchfield C, Keen N, Taylor SS

Abstract
The Ipl1/Aurora family of protein kinases are required for accurate chromosome segregation. Because members of this family are often overexpressed in human tumors, they have recently received much attention, both from the academic community and the pharmaceutical industry. Indeed, two small molecule Aurora kinase inhibitors have recently been described. In this chapter, we describe several methods for investigating the function of the Aurora kinases, focusing on Aurora B. We describe the use of the small-molecule inhibitor ZM447439, RNA interference, and overexpression of a catalytic mutant. All of these methods have proved useful in studying Aurora B as well as validating it as a potential anticancer drug target. However, while all three methods are useful for probing the function of Aurora B, each has inherent advantages and disadvantages. Furthermore, because the mechanism underlying the inhibition is different in each case, caution must be taken when interpreting the data.

PMID: 15576945 [PubMed - indexed for MEDLINE]

coxinhibitors c-met inhibitors zm-447439

Inhibition of survivin and aurora B kinase sensitizes mesothelioma cells by enhancing mitotic arrests.

Inhibition of survivin and aurora B kinase sensitizes mesothelioma cells by enhancing mitotic arrests.

Int J Radiat Oncol Biol Phys. 2007 Apr 1;67(5):1519-25

Authors: Kim KW, Mutter RW, Willey CD, Subhawong TK, Shinohara ET, Albert JM, Ling G, Cao C, Gi YJ, Lu B

Abstract
PURPOSE: Survivin, a member of the inhibitor of apoptosis gene family, has also been shown to regulate mitosis. It binds Aurora B kinase and the inner centromere protein to form the chromosome passenger complex. Both Aurora B and survivin are overexpressed in many tumors. In this study, we examined whether irradiation affected survivin and Aurora B expression in mesothelioma cells, and how inhibition of these molecules affected radiosensitivity.
METHODS AND MATERIALS: ZM447439 and survivin antisense oligonucleotides were used to inhibit survivin and Aurora B kinase respectively. Western blot was performed to determine the expression of survivin, Aurora B, phosphorylated-histone H3 (Ser 10), and caspase cleavage. Multinucleated cells were counted using flow cytometry, and cell survival after treatment was determined using clonogenic assay.
RESULTS: At 3-Gy irradiation an increase was observed in levels of survivin and Aurora B as well as the kinase activity of Aurora B, with an increase in G2/M phase. The radiation-induced upregulation of these molecules was effectively attenuated by antisense oligonucleotides against survivin and a small-molecule inhibitor of Aurora B, ZM447439. Dual inhibition of survivin and Aurora B synergistically radiosensitized mesothelioma cells with a dose enhancement ratio of 2.55. This treatment resulted in increased formation of multinucleated cells after irradiation but did not increase levels of cleaved caspase 3.
CONCLUSION: Inhibition of survivin and Aurora B induces mitotic cell arrest in mesothelioma cells after irradiation. These two proteins may be potential therapeutic targets for the enhancement of radiotherapy in malignant pleural mesothelioma.

PMID: 17394948 [PubMed - indexed for MEDLINE]

dna-pk coxinhibitors c-met inhibitors

Mitotic requirement for aurora A kinase is bypassed in the absence of aurora B kinase.

Mitotic requirement for aurora A kinase is bypassed in the absence of aurora B kinase.

FEBS Lett. 2005 Jun 20;579(16):3385-91

Authors: Yang H, Burke T, Dempsey J, Diaz B, Collins E, Toth J, Beckmann R, Ye X

PMID: 15922328 [PubMed - indexed for MEDLINE]

dna-pk coxinhibitors c-met inhibitors

Inhibition of survivin and aurora B kinase sensitizes mesothelioma cells by enhancing mitotic arrests.

Inhibition of survivin and aurora B kinase sensitizes mesothelioma cells by enhancing mitotic arrests.

Int J Radiat Oncol Biol Phys. 2007 Apr 1;67(5):1519-25

Authors: Kim KW, Mutter RW, Willey CD, Subhawong TK, Shinohara ET, Albert JM, Ling G, Cao C, Gi YJ, Lu B

PMID: 17394948 [PubMed - indexed for MEDLINE]

dovitinib dna-pk coxinhibitors

Length of mitotic arrest induced by microtubule-stabilizing drugs determines cell death after mitotic exit.

Length of mitotic arrest induced by microtubule-stabilizing drugs determines cell death after mitotic exit.

Mol Cancer Ther. 2009 Jun;8(6):1646-54

Authors: Bekier ME, Fischbach R, Lee J, Taylor WR

Abstract
Cell death induced by agents that disrupt microtubules can kill cells by inducing a prolonged mitotic block. This mitotic block is dependent on the spindle assembly checkpoint, a surveillance system that ensures the bipolar attachment of chromosomes to the mitotic spindle before the onset of anaphase. Under some conditions, the spindle assembly checkpoint can become weakened, allowing cells to exit mitosis despite the presence of chromosomes that are not properly attached to the mitotic spindle. Here, we use an Aurora kinase inhibitor to drive mitotic exit and test the effect of mitotic arrest length on death in the subsequent interphase. Cells that are blocked in mitosis for >15 h die shortly after exiting from mitosis, whereas cells that exit after being blocked for <15 h show variable fates, with some living for days after exiting mitosis. Cells blocked in mitosis by either Taxol or epothilone B are acutely sensitive to the death ligand tumor necrosis factor-related apoptosis-inducing ligand, suggesting that prolonged mitosis allows the gradual accumulation of internal death signals, rendering cells hypersensitive to additional prodeath cues. Death under these conditions is initiated while cyclin B1 is still present, indicating that cells are in mitosis. Our experiments suggest that there is a point of no return during prolonged mitotic block after which mitotic exit can no longer block death.

PMID: 19509263 [PubMed - indexed for MEDLINE]

chir-258 dovitinib dna-pk

2012年11月15日星期四

Aurora B is required for mitotic chromatin-induced phosphorylation of Op18/Stathmin.

Aurora B is required for mitotic chromatin-induced phosphorylation of Op18/Stathmin.

Proc Natl Acad Sci U S A. 2006 Mar 21;103(12):4493-8

Authors: Gadea BB, Ruderman JV

Abstract
Oncoprotein 18/Stathmin (Op18) is a microtubule-destabilizing protein that is inhibited by phosphorylation in response to many types of signals. During mitosis, phosphorylation of Op18 by cdc2 is necessary but not sufficient for Op18 inhibition. The presence of mitotic chromosomes is additionally required and involves phosphorylation of Ser-16 in Xenopus Op18 (and/or Ser-63 in human). Given that Ser-16 is an excellent Aurora A (Aur-A) kinase consensus phosphorylation site and the Aurora kinase inhibitor ZM447439 (ZM) blocks phosphorylation in the activation loop of Aur-A, we asked whether either Aur-A or Aurora B (Aur-B) might regulate Op18. We find that ZM blocks the ability of mitotic chromatin to induce Op18 hyperphosphorylation in Xenopus egg extracts. Depletion of Aur-B, but not Aur-A, blocks hyperphosphorylation of Op18, and chromatin assembled in the absence of Aur-B fails to induce hyperphosphorylation. These results suggest that Aur-B, which concentrates at centromeres of metaphase chromosomes, contributes to localized regulation of Op18 during the process of spindle assembly.

PMID: 16537398 [PubMed - indexed for MEDLINE]

rad001 ecdysone chir-258

Zwint-1 is a novel Aurora B substrate required for the assembly of a dynein-binding platform on kinetochores.

Zwint-1 is a novel Aurora B substrate required for the assembly of a dynein-binding platform on kinetochores.

Mol Biol Cell. 2011 Sep;22(18):3318-30

Authors: Kasuboski JM, Bader JR, Vaughan PS, Tauhata SB, Winding M, Morrissey MA, Joyce MV, Boggess W, Vos L, Chan GK, Hinchcliffe EH, Vaughan KT

Abstract
Aurora B (AurB) is a mitotic kinase responsible for multiple aspects of mitotic progression, including assembly of the outer kinetochore. Cytoplasmic dynein is an abundant kinetochore protein whose recruitment to kinetochores requires phosphorylation. To assess whether AurB regulates recruitment of dynein to kinetochores, we inhibited AurB using ZM447439 or a kinase-dead AurB construct. Inhibition of AurB reduced accumulation of dynein at kinetochores substantially; however, this reflected a loss of dynein-associated proteins rather than a defect in dynein phosphorylation. We determined that AurB inhibition affected recruitment of the ROD, ZW10, zwilch (RZZ) complex to kinetochores but not zwint-1 or more-proximal kinetochore proteins. AurB phosphorylated zwint-1 but not ZW10 in vitro, and three novel phosphorylation sites were identified by tandem mass spectrometry analysis. Expression of a triple-Ala zwint-1 mutant blocked kinetochore assembly of RZZ-dependent proteins and induced defects in chromosome movement during prometaphase. Expression of a triple-Glu zwint-1 mutant rendered cells resistant to AurB inhibition during prometaphase. However, cells expressing the triple-Glu mutant failed to satisfy the spindle assembly checkpoint (SAC) at metaphase because poleward streaming of dynein/dynactin/RZZ was inhibited. These studies identify zwint-1 as a novel AurB substrate required for kinetochore assembly and for proper SAC silencing at metaphase.

PMID: 21775627 [PubMed - indexed for MEDLINE]

chir-258 dovitinib dna-pk

Mitotic requirement for aurora A kinase is bypassed in the absence of aurora B kinase.

Mitotic requirement for aurora A kinase is bypassed in the absence of aurora B kinase.

FEBS Lett. 2005 Jun 20;579(16):3385-91

Authors: Yang H, Burke T, Dempsey J, Diaz B, Collins E, Toth J, Beckmann R, Ye X

PMID: 15922328 [PubMed - indexed for MEDLINE]

rad001 ecdysone chir-258

Determinants for the efficiency of anticancer drugs targeting either Aurora-A or Aurora-B kinases in human colon carcinoma cells.

Determinants for the efficiency of anticancer drugs targeting either Aurora-A or Aurora-B kinases in human colon carcinoma cells.

Mol Cancer Ther. 2009 Jul;8(7):2046-56

Authors: Kaestner P, Stolz A, Bastians H

Abstract
The mitotic Aurora kinases, including Aurora-A and Aurora- B, are attractive novel targets for anticancer therapy, and inhibitory drugs have been developed that are currently undergoing clinical trials. However, the molecular mechanisms how these drugs induce tumor cell death are poorly understood. We have addressed this question by comparing the requirements for an efficient induction of apoptosis in response to MLN8054, a selective inhibitor of Aurora-A, and the selective Aurora-B inhibitor ZM447439 in human colon carcinoma cells. By using various isogenic knockout as well as inducible colon carcinoma cell lines, we found that treatment with MLN8054 induces defects in mitotic spindle assembly, which causes a transient spindle checkpoint-dependent mitotic arrest. This cell cycle arrest is not maintained due to the activity of MLN8054 to override the spindle checkpoint. Subsequently, MLN8054-treated cells exit from mitosis and activate a p53-dependent postmitotic G(1) checkpoint, which subsequently induces p21 and Bax, leading to G(1) arrest followed by the induction of apoptosis. In contrast, inhibition of Aurora-B by ZM447439 also interferes with normal chromosome alignment during mitosis and overrides the mitotic spindle checkpoint but allows a subsequent endoreduplication, although ZM447439 potently activates the p53-dependent postmitotic G(1) checkpoint. Moreover, the ZM447439-induced endoreduplication is a prerequisite for the efficiency of the drug. Thus, our results obtained in human colon carcinoma cells indicate that although both Aurora kinase inhibitors are potent inducers of tumor cell death, the pathways leading to the induction of apoptosis in response to these drugs are distinct.

PMID: 19584233 [PubMed - indexed for MEDLINE]

rad001 ecdysone chir-258

Validating Aurora B as an anti-cancer drug target.

Validating Aurora B as an anti-cancer drug target.

J Cell Sci. 2006 Sep 1;119(Pt 17):3664-75

Authors: Girdler F, Gascoigne KE, Eyers PA, Hartmuth S, Crafter C, Foote KM, Keen NJ, Taylor SS

Abstract
The Aurora kinases, a family of mitotic regulators, have received much attention as potential targets for novel anti-cancer therapeutics. Several Aurora kinase inhibitors have been described including ZM447439, which prevents chromosome alignment, spindle checkpoint function and cytokinesis. Subsequently, ZM447439-treated cells exit mitosis without dividing and lose viability. Because ZM447439 inhibits both Aurora A and B, we set out to determine which phenotypes are due to inhibition of which kinase. Using molecular genetic approaches, we show that inhibition of Aurora B kinase activity phenocopies ZM447439. Furthermore, a novel ZM compound, which is 100 times more selective for Aurora B over Aurora A in vitro, induces identical phenotypes. Importantly, inhibition of Aurora B kinase activity induces a penetrant anti-proliferative phenotype, indicating that Aurora B is an attractive anti-cancer drug target. Using molecular genetic and chemical-genetic approaches, we also probe the role of Aurora A kinase activity. We show that simultaneous repression of Aurora A plus induction of a catalytic mutant induces a monopolar phenotype. Consistently, another novel ZM-related inhibitor, which is 20 times as potent against Aurora A compared with ZM447439, induces a monopolar phenotype. Expression of a drug-resistant Aurora A mutant reverts this phenotype, demonstrating that Aurora A kinase activity is required for spindle bipolarity in human cells. Because small molecule-mediated inhibition of Aurora A and Aurora B yields distinct phenotypes, our observations indicate that the Auroras may present two avenues for anti-cancer drug discovery.

PMID: 16912073 [PubMed - indexed for MEDLINE]

c-met inhibitors zm-447439 rad001

2012年11月14日星期三

Geminin overexpression induces mammary tumors via suppressing cytokinesis.

Geminin overexpression induces mammary tumors via suppressing cytokinesis.

Oncotarget. 2011 Dec;2(12):1011-27

Authors: Blanchard Z, Malik R, Mullins N, Maric C, Luk H, Horio D, Hernandez B, Killeen J, Elshamy WM

Abstract
Aneuploidy plays an important role in the development of cancer. Here, we uncovered an oncogenic role for geminin in mitotic cells. In addition to chromatin, tyrosine phosphorylated geminin also localizes to centrosome, spindle, cleavage furrow and midbody during mitosis. Geminin binding to Aurora B prevents its binding to INCENP, and thus activation leading to lack of histone H3-(serine 10) phosphorylation, chromosome condensation failure, aborted cytokinesis and the formation of aneuploid, drug resistance cells. Geminin overexpressing human mammary epithelial cells form aneuploid, aggressive tumors in SCID mice. Geminin is overexpressed in more than half of all breast cancers analyzed. The current study reveals that geminin is a genuine oncogene that promotes cytokinesis failure and production of aneuploid, aggressive breast tumors when overexpressed and thus a worthy therapeutic target (oncotarget) for aggressive breast cancer.

PMID: 22184288 [PubMed - indexed for MEDLINE]

dovitinib dna-pk coxinhibitors

Celecoxib synergizes human pancreatic ductal adenocarcinoma cells to sorafenib-induced growth inhibition.

Celecoxib synergizes human pancreatic ductal adenocarcinoma cells to sorafenib-induced growth inhibition.

Pancreatology. 2012 May-Jun;12(3):219-26

Authors: Rosendahl AH, Gundewar C, Said K, Karnevi E, Andersson R

Abstract
BACKGROUND: Pancreatic ductal adenocarcinoma is frequently associated with aberrant activation of the Ras/Raf/MAPK pathway and cyclooxygenase-2 (COX-2) overexpression. This study evaluated the potential for combining the multikinase inhibitor sorafenib and the specific COX-2 inhibitor celecoxib as therapy in pancreatic ductal adenocarcinoma cells.
METHODS: BxPC-3, MIAPaCa-2, PANC-1 and AsPC-1 pancreatic adenocarcinoma cells were exposed to sorafenib and celecoxib combined treatment in�vitro. Cell viability and various growth promoting and survival signaling pathways were monitored by MTT, flow cytometry and Western blotting.
RESULTS: Combined treatment with sorafenib and celecoxib synergistically inhibited pancreatic adenocarcinoma cell proliferation. This regimen produced combination index (CI) values between 0.67 and 0.92 for the various cell lines, indicating significant synergistic interactions between sorafenib and celecoxib, which also markedly inhibited the migratory capacity. The growth inhibition was associated with an accumulation of cells in the G(0)/G(1) phase of the cell cycle and induction of apoptosis. These changes were accompanied by a significant reduction of p21(WAF1/Cip1) levels, where celecoxib sensitized the cells to sorafenib-mediated p21(WAF1/Cip1) suppression.
CONCLUSION: These results suggest that combined treatment with sorafenib and celecoxib synergistically induce growth inhibition and apoptosis in pancreatic adenocarcinoma cells through a process involving p21(WAF1/Cip1) suppression.

PMID: 22687377 [PubMed - indexed for MEDLINE]

c-met inhibitors zm-447439 rad001

Inhibition of Aurora kinases perturbs chromosome alignment and spindle checkpoint signaling in rat spermatocytes.

Inhibition of Aurora kinases perturbs chromosome alignment and spindle checkpoint signaling in rat spermatocytes.

Exp Cell Res. 2006 Nov 1;312(18):3459-70

Authors: Wang Y, Toppari J, Parvinen M, Kallio MJ

Abstract
In somatic cells, integrity of cell division is safeguarded by the spindle checkpoint, a signaling cascade that delays the separation of sister chromatids in the presence of misaligned chromosomes. Aurora kinases play important roles in this process by promoting centrosome maturation, chromosome bi-orientation, spindle checkpoint signaling, and cytokinesis. To investigate the functions of Aurora kinases in male meiosis, we applied a small molecule Aurora inhibitor, ZM447439, to seminiferous tubules in vitro. Primary and secondary spermatocytes exposed to ZM447439 exhibit defects in the spindle morphology and fail to align their chromosomes at the metaphase plate. Moreover, the treated spermatocytes undergo a forced exit from the meiotic M-phase without cytokinesis. These results suggest that the activities of Aurora kinases are required for normal spindle assembly as well as for establishment and maintenance of proper microtubule-kinetochore attachments and spindle checkpoint signaling in male mammalian meiosis.

PMID: 16962097 [PubMed - indexed for MEDLINE]

chir-258 dovitinib dna-pk

Phosphorylation of histone H3 serine 10 in early mouse embryos: active phosphorylation at late S phase and differential effects of ZM447439 on first two embryonic mitoses.

Phosphorylation of histone H3 serine 10 in early mouse embryos: active phosphorylation at late S phase and differential effects of ZM447439 on first two embryonic mitoses.

Cell Cycle. 2010 Dec 1;9(23):4674-87

Authors: Teperek-Tkacz M, Meglicki M, Pasternak M, Kubiak JZ, Borsuk E

Abstract
Cell division in mammalian cells is regulated by Aurora kinases. The activity of Aurora A is indispensable for correct function of centrosomes and proper spindle formation, while Aurora B for chromosome biorientation and separation. Aurora B is also responsible for the phosphorylation of histone H3 serine 10 (H3S10Ph) from G2 to metaphase. Data concerning the Aurora B activity and H3S10Ph in embryonic cells are limited to primordial and maturing oocytes and advanced pronuclei in zygotes. In the present study we have analyzed H3S10Ph in 1- and 2-cell mouse embryos. We show that H3S10 remains phosphorylated at anaphase and telophase of the second meiotic division, as well as during the anaphase and telophase of the first and second embryonic mitoses. At late G1 H3S10 is dephosphorylated and subsequently phosphorylated de novo at late S phase of the first and second cell cycle. These results show that the H3S10 phosphorylation/dephosphorylation cycle in embryonic cells is different than in somatic cells. The behaviour of thymocyte G0 nuclei introduced into ovulated oocytes and early 1-cell parthenogenotes confirms that kinases responsible for de novo H3S10 phosphorylation, most probably Aurora B,� are active until G1 of the first cell cycle of mouse embryo. The inhibition of Aurora kinases by ZM447439 caused abnormalities both in the first and second mitoses. However, the disturbances in each division differed, suggesting important differences in the control of these mitoses. In ZM447439-treated mitotic zygotes Mad2 protein remained continuously present on kinetochores, what confirmed that spindle checkpoint remained active.

PMID: 21099354 [PubMed - indexed for MEDLINE]

rad001 ecdysone chir-258

HYDROGEN PEROXIDE AND ECDYSONE IN THE CRYOPROTECTIVE DEHYDRATION STRATEGY OF Megaphorura Arctica (ONYCHIURIDAE: COLLEMBOLA).

HYDROGEN PEROXIDE AND ECDYSONE IN THE CRYOPROTECTIVE DEHYDRATION STRATEGY OF Megaphorura Arctica (ONYCHIURIDAE: COLLEMBOLA).

Arch Insect Biochem Physiol. 2012 Nov 12;

Authors: Grubor-Laj?i? G, Petri ET, Koji? D, Pura? J, Popovi? ZD, Worland RM, Clark MS, Mojovi? M, Blagojevi? DP

Abstract
The Arctic springtail, Megaphorura arctica, survives sub-zero temperatures in a dehydrated state via trehalose-dependent cryoprotective dehydration. Regulation of trehalose biosynthesis is complex; based in part on studies in yeast and fungi, its connection with oxidative stress caused by exposure of cells to oxidants, such as hydrogen peroxide (H(2) O(2) ), or dehydration, is well documented. In this respect, we measured the amount of H(2) O(2) and antioxidant enzyme activities (superoxide dismutases: copper, zinc-CuZnSOD and manganese containing-MnSOD, and catalase-CAT), as the regulatory components determining H(2) O(2) concentrations, in Arctic springtails incubated at 5 �C (control) versus -2 �C (threshold temperature for trehalose biosynthesis). Because ecdysone also stimulates trehalose production in insects and regulates the expression of genes involved in redox homeostasis and antioxidant protection in Drosophila, we measured the levels of the active physiological form of ecdysone-20-hydroxyecdysone (20-HE). Significantly elevated H(2) O(2) and 20-HE levels were observed in M. arctica incubated at -2 �C, supporting a link between ecdysone, H(2) O(2) , and trehalose levels during cryoprotective dehydration. CAT activity was found to be significantly lower in M. arctica incubated at -2 �C versus 5 �C, suggesting reduced H(2) O(2) breakdown. Furthermore, measurement of the free radical composition in Arctic springtails incubated at 5 �C (controls) versus -2 �C by Electron Paramagnetic Resonance spectroscopy revealed melanin-derived free radicals at -2 �C, perhaps an additional source of H(2) O(2) . Our results suggest that H(2) O(2) and ecdysone play important roles in the cryoprotective dehydration process in M. arctica, linked with the regulation of trehalose biosynthesis.

PMID: 23143920 [PubMed - as supplied by publisher]

ecdysone chir-258 dovitinib

2012年11月13日星期二

Short and long-term tumor cell responses to Aurora kinase inhibitors.

Short and long-term tumor cell responses to Aurora kinase inhibitors.

Exp Cell Res. 2009 Apr 15;315(7):1085-99

Authors: Dreier MR, Grabovich AZ, Katusin JD, Taylor WR

Abstract
Aurora kinases are essential for mitosis and are candidate targets of novel chemotherapeutic agents. The inhibitors ZM447439, MK-0457 (VX-680) as well as Hesperadin have been used to dissect the roles of Aurora kinases in the cell cycle and have been tested clinically for the treatment of cancer. Here we have carried out a detailed kinetic analysis of two isogenic cell lines differing in p53 function and have compared the effects of ZM447439 and VE-465 (related to MK-0457). We find that p53 is needed for efficient cell cycle arrest when Aurora kinases are inhibited by either ZM447439 or VE-465. However, the p53-induced cell cycle block is neither immediate nor absolute. ZM447439 induced the localized accumulation of gammaH2A.X indicating that p53 induction by this drug occurs in response to DNA damage. Our analysis of the long-term effects of ZM447439 indicates that cells can evade killing by the drug, but not via a classical drug-resistance mechanism. Several mechanisms to explain how cells may evade killing by Aurora kinase inhibitors are described.

PMID: 19233169 [PubMed - indexed for MEDLINE]

rad001 ecdysone chir-258

Dawn of Aurora kinase inhibitors as anticancer drugs.

Dawn of Aurora kinase inhibitors as anticancer drugs.

Expert Opin Investig Drugs. 2004 Sep;13(9):1199-201

Authors: Doggrell SA

Abstract
With the current standard chemotherapy regimens only approximately 25% of acute myelogenous leukaemia (AML) patients survive > 5 years. Aurora kinases are overexpressed in many human cancers. VX-680 inhibited Aurora-A, -B, -C and the FMS-like tyrosine kinase-3 with apparent inhibitory constants of 0.6, 18, 4.6 and 30 nM, respectively. In primary leukaemia cells from patients with AML, which were refractory to standard therapies, VX-680 inhibited colony formation. In nude mice, VX-680 markedly reduced human AML tumours. The development of VX-680 for use in AML should continue.

PMID: 15330750 [PubMed - indexed for MEDLINE]

dovitinib dna-pk coxinhibitors

Inhibition of Aurora kinases perturbs chromosome alignment and spindle checkpoint signaling in rat spermatocytes.

Inhibition of Aurora kinases perturbs chromosome alignment and spindle checkpoint signaling in rat spermatocytes.

Exp Cell Res. 2006 Nov 1;312(18):3459-70

Authors: Wang Y, Toppari J, Parvinen M, Kallio MJ

PMID: 16962097 [PubMed - indexed for MEDLINE]

ecdysone chir-258 dovitinib

Length of mitotic arrest induced by microtubule-stabilizing drugs determines cell death after mitotic exit.

Length of mitotic arrest induced by microtubule-stabilizing drugs determines cell death after mitotic exit.

Mol Cancer Ther. 2009 Jun;8(6):1646-54

Authors: Bekier ME, Fischbach R, Lee J, Taylor WR

PMID: 19509263 [PubMed - indexed for MEDLINE]

c-met inhibitors zm-447439 rad001

2012年11月12日星期一

Dual inhibition of Met kinase and angiogenesis to overcome HGF-induced EGFR-TKI resistance in EGFR mutant lung cancer.

Dual inhibition of Met kinase and angiogenesis to overcome HGF-induced EGFR-TKI resistance in EGFR mutant lung cancer.

Am J Pathol. 2012 Sep;181(3):1034-43

Authors: Takeuchi S, Wang W, Li Q, Yamada T, Kita K, Donev IS, Nakamura T, Matsumoto K, Shimizu E, Nishioka Y, Sone S, Nakagawa T, Uenaka T, Yano S

Abstract
Acquired resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) is a serious problem in the management of EGFR mutant lung cancer. We recently reported that hepatocyte growth factor (HGF) induces resistance to EGFR-TKIs by activating the Met/PI3K pathway. HGF is also known to induce angiogenesis in cooperation with vascular endothelial growth factor (VEGF), which is an important therapeutic target in lung cancer. Therefore, we hypothesized that dual inhibition of HGF and VEGF may be therapeutically useful for controlling HGF-induced EGFR-TKI-resistant lung cancer. We found that a dual Met/VEGF receptor 2 kinase inhibitor, E7050, circumvented HGF-induced EGFR-TKI resistance in EGFR mutant lung cancer cell lines by inhibiting the Met/Gab1/PI3K/Akt pathway in vitro. HGF stimulated VEGF production by activation of the Met/Gab1 signaling pathway in EGFR mutant lung cancer cell lines, and E7050 showed an inhibitory effect. In a xenograft model, tumors produced by HGF-transfected Ma-1 (Ma-1/HGF) cells were more angiogenic than vector control tumors and showed resistance to gefitinib. E7050 alone inhibited angiogenesis and retarded growth of Ma-1/HGF tumors. E7050 combined with gefitinib induced marked regression of tumor growth. Moreover, dual inhibition of HGF and VEGF by neutralizing antibodies combined with gefitinib also markedly regressed tumor growth. These results indicate the therapeutic rationale of dual targeting of HGF-Met and VEGF-VEGF receptor 2 for overcoming HGF-induced EGFR-TKI resistance in EGFR mutant lung cancer.

PMID: 22789825 [PubMed - indexed for MEDLINE]

coxinhibitors c-met inhibitors zm-447439

Histone post-translational modification: from discovery to the clinic.

Histone post-translational modification: from discovery to the clinic.

IDrugs. 2006 Jun;9(6):398-401

Authors: Thomas NR

PMID: 16752306 [PubMed - indexed for MEDLINE]

chir-258 dovitinib dna-pk

Analysis of mitotic phosphorylation of borealin.

Analysis of mitotic phosphorylation of borealin.

BMC Cell Biol. 2007;8:5

Authors: Kaur H, Stiff AC, Date DA, Taylor WR

Abstract
BACKGROUND: The main role of the chromosomal passenger complex is to ensure that Aurora B kinase is properly localized and activated before and during mitosis. Borealin, a member of the chromosomal passenger complex, shows increased expression during G2/M phases and is involved in targeting the complex to the centromere and the spindle midzone, where it ensures proper chromosome segregation and cytokinesis. Borealin has a consensus CDK1 phosphorylation site, threonine 106 and can be phosphorylated by Aurora B Kinase at serine 165 in vitro.
RESULTS: Here, we show that Borealin is phosphorylated during mitosis in human cells. Dephosphorylation of Borealin occurs as cells exit mitosis. The phosphorylated form of Borealin is found in an INCENP-containing complex in mitosis. INCENP-containing complexes from cells in S phase are enriched in the phosphorylated form suggesting that phosphorylation may encourage entry of Borealin into the chromosomal passenger complex. Although Aurora B Kinase is found in complexes that contain Borealin, it is not required for the mitotic phosphorylation of Borealin. Mutation of T106 or S165 of Borealin to alanine does not alter the electrophoretic mobility shift of Borealin. Experiments with cyclohexamide and the phosphatase inhibitor sodium fluoride suggest that Borealin is phosphorylated by a protein kinase that can be active in interphase and mitosis and that the phosphorylation may be regulated by a short-lived phosphatase that is active in interphase but not mitosis.
CONCLUSION: Borealin is phosphorylated during mitosis. Neither residue S165, T106 nor phosphorylation of Borealin by Aurora B Kinase is required to generate the mitotic, shifted form of Borealin. Suppression of phosphorylation during interphase is ensured by a labile protein, possibly a cell cycle regulated phosphatase.

PMID: 17241471 [PubMed - indexed for MEDLINE]

chir-258 dovitinib dna-pk

Sensitivity of BRCA2 mutated human cell lines to Aurora kinase inhibition.

Sensitivity of BRCA2 mutated human cell lines to Aurora kinase inhibition.

Invest New Drugs. 2012 Apr;30(2):425-34

Authors: Vidarsdottir L, Steingrimsdottir G, Bodvarsdottir SK, Ogmundsdottir HM, Eyfjord JE

Abstract
Aurora kinases play a vital part in successful mitosis and cell division. Aberrant Aurora-A and -B expression is commonly seen in various types of tumors. Small molecule Aurora inhibitors have already entered clinical trials. Aurora-A amplification has been shown to be associated with breast tumors from BRCA2-mutation carriers and such patients might therefore be candidates for treatment with Aurora kinase inhibitors. There is a need to identify markers that can predict sensitivity to Aurora inhibition. In this study sensitivity to the inhibitor ZM447439 was tested on a panel of 15 non-malignant and malignant epithelial cell lines that differed with respect to BRCA2 and p53 status and related to level of Aurora kinase expression. The IC(50) value for cell survival ranged from 1.9-8.1 ?M and was not related to presence or absence of BRCA2 mutation. The levels of Aurora-A and -B expression correlated with each other but sensitivity towards ZM447439 did not correlate with levels of Aurora-A and -B mRNA expression, alone. Cells treated with the Aurora kinase inhibitor completed mitosis but cytokinesis was inhibited resulting in polyploidy and multinucleation. Different levels of polyploidy could not be fully explained by defects in p53. Only cell lines with a combination of high Aurora-A and -B expression, BRCA2 mutation and p53 defects showed more sensitivity towards Aurora inhibition than other cell lines. In conclusion, BRCA2-mutated cells showed variable sensitivity towards Aurora kinase inhibition. The level of sensitivity could not be predicted by Aurora expression levels alone but BRCA2 mutated tumors with high Aurora expression and non-functional p53 are likely candidates for treatment with Aurora inhibitors.

PMID: 20960027 [PubMed - indexed for MEDLINE]

chir-258 dovitinib dna-pk

A novel treatment strategy targeting Aurora kinases in acute myelogenous leukemia.

A novel treatment strategy targeting Aurora kinases in acute myelogenous leukemia.

Mol Cancer Ther. 2007 Jun;6(6):1851-7

Authors: Ikezoe T, Yang J, Nishioka C, Tasaka T, Taniguchi A, Kuwayama Y, Komatsu N, Bandobashi K, Togitani K, Koeffler HP, Taguchi H

Abstract
The Aurora kinases play an important role in chromosome alignment, segregation, and cytokinesis during mitosis. Aberrant expression of these kinases occurs in solid tumors and is associated with aneuploidy and carcinogenesis. We found in this study that Aurora kinase A and B were aberrantly expressed in a variety of types of human leukemia cell lines (n = 15, e.g., PALL-1, PALL-2, HL-60, NB4, MV4-11, etc.), as well as freshly isolated leukemia cells from individuals with acute myelogenous leukemia (n = 44) compared with bone marrow mononuclear cells from healthy volunteers (n = 11), as measured by real-time PCR. ZM447439 is a novel selective Aurora kinase inhibitor. The compound induced growth inhibition, caused accumulation of cells with 4N/8N DNA content, and mediated apoptosis of human leukemia cells as measured by thymidine uptake, cell cycle analysis, and annexin V staining, respectively. Especially profound growth inhibition occurred with the PALL-1 and PALL-2 cells, which possess wild-type p53 gene. In contrast, ZM447439 did not inhibit clonogenic growth of myeloid committed stem cells harvested from healthy normal volunteers. Taken together, inhibition of Aurora kinases may be a promising treatment strategy for individuals with leukemia.

PMID: 17541033 [PubMed - indexed for MEDLINE]

rad001 ecdysone chir-258

2012年11月11日星期日

Caffeine promotes apoptosis in mitotic spindle checkpoint-arrested cells.

Caffeine promotes apoptosis in mitotic spindle checkpoint-arrested cells.

J Biol Chem. 2007 Mar 9;282(10):6954-64

Authors: Gabrielli B, Chau YQ, Giles N, Harding A, Stevens F, Beamish H

Abstract
The spindle assembly checkpoint arrests cells in mitosis when defects in mitotic spindle assembly or partitioning of the replicated genome are detected. This checkpoint blocks exit from mitosis until the defect is rectified or the cell initiates apoptosis. In this study we have used caffeine to identify components of the mechanism that signals apoptosis in mitotic checkpoint-arrested cells. Addition of caffeine to spindle checkpoint-arrested cells induced >40% apoptosis within 5 h. It also caused proteasome-mediated destruction of cyclin B1, a corresponding reduction in cyclin B1/cdk1 activity, and reduction in MPM-2 reactivity. However, cells retained MAD2 staining at the kinetochores, an indication of continued spindle checkpoint function. Blocking proteasome activity did not block apoptosis, but continued spindle checkpoint function was essential for apoptosis. After systematically eliminating all known targets, we have identified p21-activated kinase PAK1, which has an anti-apoptotic function in spindle checkpoint-arrested cells, as a target for caffeine inhibition. Knockdown of PAK1 also increased apoptosis in spindle checkpoint-arrested cells. This study demonstrates that the spindle checkpoint not only regulates mitotic exit but apoptosis in mitosis through the activity of PAK1.

PMID: 17182611 [PubMed - indexed for MEDLINE]

zm-447439 rad001 ecdysone

Inhibition of survivin and aurora B kinase sensitizes mesothelioma cells by enhancing mitotic arrests.

Inhibition of survivin and aurora B kinase sensitizes mesothelioma cells by enhancing mitotic arrests.

Int J Radiat Oncol Biol Phys. 2007 Apr 1;67(5):1519-25

Authors: Kim KW, Mutter RW, Willey CD, Subhawong TK, Shinohara ET, Albert JM, Ling G, Cao C, Gi YJ, Lu B

PMID: 17394948 [PubMed - indexed for MEDLINE]

c-met inhibitors zm-447439 rad001

Aurora B confers cancer cell resistance to TRAIL-induced apoptosis via phosphorylation of survivin.

Aurora B confers cancer cell resistance to TRAIL-induced apoptosis via phosphorylation of survivin.

Carcinogenesis. 2012 Mar;33(3):492-500

Authors: Yoon MJ, Park SS, Kang YJ, Kim IY, Lee JA, Lee JS, Kim EG, Lee CW, Choi KS

Abstract
Tumor necrosis factor-related apoptosis-induced ligand (TRAIL) induces apoptosis selectively in cancer cells while sparing normal cells. However, many cancer cells are resistant to TRAIL-induced cell death. In this study, we examined whether Aurora B, which is frequently overexpressed in cancer cells, is associated with TRAIL resistance. The protein levels of Aurora B were higher in TRAIL-resistant cancer cell lines than in TRAIL-sensitive cancer cell lines. Exogenously expressed Aurora B attenuated TRAIL-induced apoptosis in the tested TRAIL-sensitive cancer cell lines, whereas the small interfering RNA-mediated suppression of Aurora B expression stimulated TRAIL-mediated apoptosis in the tested TRAIL-resistant cancer cell lines. Furthermore, combined treatment with TRAIL and ZM447439, a specific inhibitor of Aurora B, synergistically induced apoptosis in various TRAIL-resistant cancer cells, suggesting that this combined regimen may represent an attractive strategy for effectively treating TRAIL-resistant malignant cancers. Mechanistically, the inhibition of Aurora B activity in various cancer cells commonly downregulated survivin protein levels and potentiated the activation of caspase-3. In addition, Aurora B inhibition induced mitotic catastrophe, which also contributed to the sensitization of cells to TRAIL-mediated apoptosis. Interestingly, forced overexpression of Aurora B increased the protein levels of survivin, but not those of a non-phosphorylatable survivin mutant in which threonine 117 was replaced by alanine, indicating that phosphorylation of survivin is required for this effect. Furthermore, TRAIL-induced apoptosis in MDA-MB-435S cells was attenuated by wild-type survivin but not by the non-phosphorylatable survivin mutant. Collectively, our results demonstrate that Aurora B confers TRAIL resistance to cancer cells via phosphorylation of survivin.

PMID: 22159225 [PubMed - indexed for MEDLINE]

chir-258 dovitinib dna-pk

Insights from the docking analysis of biologically active compounds from plant Litsea Genus as potential COX-2 inhibitors.

Insights from the docking analysis of biologically active compounds from plant Litsea Genus as potential COX-2 inhibitors.

Bioinformation. 2012;8(17):812-5

Authors: Gogoi D, Bezbaruah RL, Bordoloi M, Sarmah R, Bora TC

Abstract
Litsea spp of Laural family are traditionally used as herbal medicine for treating inflammation including gastroenterologia, oedema and rheumatic arthritis. Therefore, it is of interest to investigate and understand the molecular principles for such actions. Here, we have illustrated the binding of thirteen Litsea derived biologically active compounds against the inflammation associated target COX (cyclo-oxygenase) -2 enzymes. We compared the binding information of these compounds with a selected number of already known COX-2 inhibitors. The comparison reflected that some of these compounds such as linderol, catechin, 6'-hydroxy-2',3',4' - trimethoxy-chalcone and litseaone have better or equivalent binding features compared to already known inhibitory compounds namely celecoxib, acetylsalicylic acid, rofecoxib. Therefore, all these small compounds reported from plant Litsea spp were found to possess potential medicinal values with anti-inflammatory properties.

PMID: 23139590 [PubMed - in process]

rad001 ecdysone chir-258

Geminin overexpression induces mammary tumors via suppressing cytokinesis.

Geminin overexpression induces mammary tumors via suppressing cytokinesis.

Oncotarget. 2011 Dec;2(12):1011-27

Authors: Blanchard Z, Malik R, Mullins N, Maric C, Luk H, Horio D, Hernandez B, Killeen J, Elshamy WM

PMID: 22184288 [PubMed - indexed for MEDLINE]

chir-258 dovitinib dna-pk

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