5-alpha-reductase

coxinhibitors c-met inhibitors zm-447439

Erythrocytic Pyruvate Kinase Mutations Causing Hemolytic Anemia, Osteosclerosis, and Secondary Hemochromatosis in Dogs.

Erythrocytic Pyruvate Kinase Mutations Causing Hemolytic Anemia, Osteosclerosis, and Secondary Hemochromatosis in Dogs.

J Vet Intern Med. 2012 Jul 13;

Authors: Inal Gultekin G, Raj K, Foureman P, Lehman S, Manhart K, Abdulmalik O, Giger U

Abstract
BACKGROUND: Erythrocytic pyruvate kinase (PK) deficiency, first documented in Basenjis, is the most common inherited erythroenzymopathy in dogs. OBJECTIVES: To report 3 new breed-specific PK-LR gene mutations and a retrospective survey of PK mutations in a small and selected group of Beagles and West Highland White Terriers (WHWT). ANIMALS: Labrador Retrievers (2 siblings, 5 unrelated), Pugs (2 siblings, 1 unrelated), Beagles (39 anemic, 29 other), WHWTs (22 anemic, 226 nonanemic), Cairn Terrier (n�=�1). METHODS: Exons of the PK-LR gene were sequenced from genomic DNA of young dogs (<2�years) with persistent highly regenerative hemolytic anemia. RESULTS: A nonsense mutation (c.799C>T) resulting in a premature stop codon was identified in anemic Labrador Retriever siblings that had osteosclerosis, high serum ferritin concentrations, and severe hepatic secondary hemochromatosis. Anemic Pug and Beagle revealed 2 different missense mutations (c.848T>C, c.994G>A, respectively) resulting in intolerable amino acid changes to protein structure and enzyme function. Breed-specific mutation tests were developed. Among the biased group of 248 WHWTs, 9% and 35% were homozygous (affected) and heterozygous, respectively, for the previously described mutation (mutant allele frequency 0.26). A PK-deficient Cairn Terrier had the same insertion mutation as the affected WHWTs. Of the selected group of 68 Beagles, 35% were PK-deficient and 3% were carriers (0.37). CONCLUSIONS AND CLINICAL IMPORTANCE: Erythrocytic PK deficiency is caused by different mutations in different dog breeds and causes chronic severe hemolytic anemia, hemosiderosis, and secondary hemochromatosis because of chronic hemolysis and, an as yet unexplained osteosclerosis. The newly developed breed-specific mutation assays simplify the diagnosis of PK deficiency.

PMID: 22805166 [PubMed - as supplied by publisher]

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Emtricitabine/tenofovir in the treatment of HIV infection: current PK/PD evaluation.

Emtricitabine/tenofovir in the treatment of HIV infection: current PK/PD evaluation.

Expert Opin Drug Metab Toxicol. 2012 Oct;8(10):1305-14

Authors: Uglietti A, Zanaboni D, Gnarini M, Maserati R

Abstract
Introduction: Emtricitabine/tenofovir disoproxil fumarate fixed-dose combination (FTC/TDF FDC) is the co-formulation of a nucleoside and a nucleotide, respectively. After oral administration, both drugs exhibit plasma and intracellular half-lives suitable for once-daily dosing. Within the host cells, active metabolites FTC-TP and TFV-DP act as chain terminators to the newly synthesized proviral DNA, showing synergy at enzymatic level (viral reverse transcriptase). When given in HAART combinations, FTC/TDF FDC has a remarkable effectiveness in controlling HIV replication and securing a significant CD4(+) cell recovery. If patients treated with FTC/TDF FDC fail, a lower incidence of TDF-associated K65R resistance mutation seems to develop. Furthermore, cytidine analog-associated M184V is less likely to appear with FTC than with lamivudine when both are given with TDF. FTC and TFV are not metabolized by CYP450 enzymes and are eliminated by the renal route. TFV may accumulate in tubular cells and cause a decrease in GFR and a loss of phosphates. As a onsequence, patients treated with FTC/TDF FCD may experience varied degrees of renal impairment and osteopenia/osteoporosis. Areas covered: This paper has focused on the PK/PD features of FTC and TDF, when given as single agent or when administered as FDC. The interpretation of efficacy/toxicity was guided by PK/PD features. The review of the available literature included also conference presentations and recent guidelines (as of May 2012). Expert opinion: FTC/TDF FDC is a potent and reliable component of most HAART combinations due to its maintained activity across time, as demonstrated in many trials and studies. Toxicity issues (kidney, bone) are still to be entirely elucidated and the drug-induced component well separated from patient- and HIV-related ones. However, the clinical gain associated with the use of FTC/TDF FDC is fully acknowledged by its leading position in most current treatment guidelines.

PMID: 22943210 [PubMed - in process]

2012年10月5日星期五

Frequent overexpression of aurora B kinase, a novel drug target, in non-small cell lung carcinoma patients.

Frequent overexpression of aurora B kinase, a novel drug target, in non-small cell lung carcinoma patients.

Mol Cancer Ther. 2006 Nov;5(11):2905-13

Authors: Vischioni B, Oudejans JJ, Vos W, Rodriguez JA, Giaccone G

Abstract
The serine/threonine protein kinase aurora B, a key regulator of mitosis, is emerging as a novel drug target for cancer treatment. Aurora B overexpression has been previously documented by immunohistochemistry in several types of human tumors. We assessed aurora B expression in a series of 160 non-small cell lung cancer (NSCLC) samples (60% stage I, 21% stage II, 11% stage III, and 8% stage IV). In addition, we determined the expression of survivin and p16, two molecules also involved in cell cycle control. Aurora B was expressed selectively in tumor cells compared with normal epithelium. Aurora B expression was significantly correlated with expression of survivin in the nucleus (P < 0.0001), but not with expression of p16 (P = 0.134). High aurora B expression levels were significantly associated with older age (P = 0.012), male sex (P = 0.013), squamous cell carcinoma histology (P = 0.001), poor tumor differentiation grade (P = 0.007), and lymph node invasion (P = 0.037), in the subset of radically resected patients in our series. In addition, aurora B expression predicted shorter survival for the patients with adenocarcinoma histology, at both univariate (P = 0.020) and multivariate (P = 0.012) analysis. Survivin expression levels were neither associated with patient clinicopathologic characteristics nor with survival. However, expression of survivin in the nucleus was preferentially detected in stage I and II than in stage III and IV (P = 0.007) in the overall series of NSCLC samples. Taken together, our results suggest that aurora B may represent a valid target in NSCLC.

PMID: 17121938 [PubMed - indexed for MEDLINE]

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Neither Aurora B activity nor histone H3 phosphorylation is essential for chromosome condensation during meiotic maturation of porcine oocytes.

Neither Aurora B activity nor histone H3 phosphorylation is essential for chromosome condensation during meiotic maturation of porcine oocytes.

Biol Reprod. 2006 May;74(5):905-12

Authors: Jel�nkov� L, Kubelka M

Abstract
Aurora kinase B (AURKB) is a chromosomal passenger protein that is essential for a number of processes during mitosis. Its activity is regulated by association with two other passenger proteins, INCENP and Survivin, and by phosphorylation on Thr 232. In this study, we examine expression and phosphorylation on Thr-232 of AURKB during meiotic maturation of pig oocytes in correlation with histone H3 phosphorylation and chromosome condensation. We show that histone H3 phosphorylation on Ser-10, but not on Ser-28, correlates with progressive chromosome condensation during oocyte maturation; Ser-10 phosphorylation starts around the time of the breakdown of the nuclear envelope, with the maximal activity in metaphase I, whereas Ser-28 phosphorylation does not significantly change in maturing oocytes. Treatment of oocytes with 50 microM butyrolactone I (BL-I), an inhibitor of cyclin-dependent kinases, or cycloheximide (10 microg/ml), inhibitor of proteosynthesis, results in a block of oocytes in the germinal vesicle stage, when nuclear membrane remains intact; however, condensed chromosome fibers or highly condensed chromosome bivalents can be seen in the nucleoplasm of BL-I- or cycloheximide-treated oocytes, respectively. In these treated oocytes, no or only very weak AURKB activity and phosphorylation of histone H3 on Ser-10 can be detected after 27 h of treatment, whereas phosphorylation on Ser-28 is not influenced. These results suggest that AURKB activity and Ser-10 phosphorylation of histone H3 are not required for chromosome condensation in pig oocytes, but might be required for further processing of chromosomes during meiosis.

PMID: 16452462 [PubMed - indexed for MEDLINE]

A validated tumorgraft model reveals activity of dovitinib against renal cell carcinoma.

A validated tumorgraft model reveals activity of dovitinib against renal cell carcinoma.

Sci Transl Med. 2012 Jun 6;4(137):137ra75

Authors: Sivanand S, Pe�a-Llopis S, Zhao H, Kucejova B, Spence P, Pavia-Jimenez A, Yamasaki T, McBride DJ, Gillen J, Wolff NC, Morlock L, Lotan Y, Raj GV, Sagalowsky A, Margulis V, Cadeddu JA, Ross MT, Bentley DR, Kabbani W, Xie XJ, Kapur P, Williams NS, Brugarolas J

Abstract
Most anticancer drugs entering clinical trials fail to achieve approval from the U.S. Food and Drug Administration. Drug development is hampered by the lack of preclinical models with therapeutic predictive value. Herein, we report the development and validation of a tumorgraft model of renal cell carcinoma (RCC) and its application to the evaluation of an experimental drug. Tumor samples from 94 patients were implanted in the kidneys of mice without additives or disaggregation. Tumors from 35 of these patients formed tumorgrafts, and 16 stable lines were established. Samples from metastatic sites engrafted at higher frequency than those from primary tumors, and stable engraftment of primary tumors in mice correlated with decreased patient survival. Tumorgrafts retained the histology, gene expression, DNA copy number alterations, and more than 90% of the protein-coding gene mutations of the corresponding tumors. As determined by the induction of hypercalcemia in tumorgraft-bearing mice, tumorgrafts retained the ability to induce paraneoplastic syndromes. In studies simulating drug exposures in patients, RCC tumorgraft growth was inhibited by sunitinib and sirolimus (the active metabolite of temsirolimus in humans), but not by erlotinib, which was used as a control. Dovitinib, a drug in clinical development, showed greater activity than sunitinib and sirolimus. The routine incorporation of models recapitulating the molecular genetics and drug sensitivities of human tumors into preclinical programs has the potential to improve oncology drug development.

PMID: 22674553 [PubMed - indexed for MEDLINE]

The Aurora kinase inhibitor ZM447439 accelerates first meiosis in mouse oocytes by overriding the spindle assembly checkpoint.

The Aurora kinase inhibitor ZM447439 accelerates first meiosis in mouse oocytes by overriding the spindle assembly checkpoint.

Reproduction. 2010 Oct;140(4):521-30

Authors: Lane SI, Chang HY, Jennings PC, Jones KT

Abstract
Previous studies have established that when maturing mouse oocytes are continuously incubated with the Aurora inhibitor ZM447439, meiotic maturation is blocked. In this study, we observe that by altering the time of addition of the inhibitor, oocyte maturation can actually be accelerated by 1 h as measured by the timing of polar body extrusion. ZM447439 also had the ability to overcome a spindle assembly checkpoint (SAC) arrest caused by nocodazole and so rescue polar body extrusion. Consistent with the ability of the SAC to inhibit cyclin B1 degradation by blocking activation of the anaphase-promoting complex, we could also observe a rescue in cyclin B1 degradation when ZM447439 was added to nocodazole-treated oocytes. The acceleration of the first meiotic division by ZM447439, which has not been achieved previously, and its effects on the SAC are all consistent with the proposed mitotic role of Aurora B in activating the SAC. We hypothesize that Aurora kinase activity controls the SAC in meiosis I, despite differences to the mitotic cell cycle division in spindle architecture brought about by the meiotic mono-orientation of sister kinetochores.

PMID: 20660090 [PubMed - indexed for MEDLINE]

Trivalent dimethylarsenic compound induces histone H3 phosphorylation and abnormal localization of Aurora B kinase in HepG2 cells.

Trivalent dimethylarsenic compound induces histone H3 phosphorylation and abnormal localization of Aurora B kinase in HepG2 cells.

Toxicol Appl Pharmacol. 2009 Dec 15;241(3):275-82

Authors: Suzuki T, Miyazaki K, Kita K, Ochi T

Abstract
Trivalent dimethylarsinous acid [DMA(III)] has been shown to induce mitotic abnormalities, such as centrosome abnormality, multipolar spindles, multipolar division, and aneuploidy, in several cell lines. In order to elucidate the mechanisms underlying these mitotic abnormalities, we investigated DMA(III)-mediated changes in histone H3 phosphorylation and localization of Aurora B kinase, which is a key molecule in cell mitosis. DMA(III) caused the phosphorylation of histone H3 (ser10) and was distributed predominantly in mitotic cells, especially in prometaphase cells. By contrast, most of the phospho-histone H3 was found to be localized in interphase cells after treatment with inorganic arsenite [iAs(III)], suggesting the involvement of a different pathway in phosphorylation. DMA(III) activated Aurora B kinase and slightly activated ERK MAP kinase. Phosphorylation of histone H3 by DMA(III) was effectively reduced by ZM447439 (Aurora kinase inhibitor) and slightly reduced by U0126 (MEK inhibitor). By contrast, iAs(III)-dependent histone H3 phosphorylation was markedly reduced by U0126. Aurora B kinase is generally localized in the midbody during telophase and plays an important role in cytokinesis. However, in some cells treated with DMA(III), Aurora B was not localized in the midbody of telophase cells. These findings suggested that DMA(III) induced a spindle abnormality, thereby activating the spindle assembly checkpoint (SAC) through the Aurora B kinase pathway. In addition, cytokinesis was not completed because of the abnormal localization of Aurora B kinase by DMA(III), thereby resulting in the generation of multinucleated cells. These results provide insight into the mechanism of arsenic tumorigenesis.

PMID: 19716834 [PubMed - indexed for MEDLINE]

2012年10月4日星期四

Fulminant acneiform eruptions after administration of dovitinib in a patient with renal cell carcinoma.

Fulminant acneiform eruptions after administration of dovitinib in a patient with renal cell carcinoma.

J Clin Oncol. 2011 Apr 20;29(12):e340-1

Authors: Hsiao YW, Lin YC, Hui RC, Yang CH

PMID: 21263088 [PubMed - indexed for MEDLINE]

Molecular targets of the antiinflammatory Harpagophytum procumbens (devil's claw): inhibition of TNF? and COX-2 gene expression by preventing activation of AP-1.

Molecular targets of the antiinflammatory Harpagophytum procumbens (devil's claw): inhibition of TNF? and COX-2 gene expression by preventing activation of AP-1.

Phytother Res. 2012 Jun;26(6):806-11

Authors: Fiebich BL, Mu�oz E, Rose T, Weiss G, McGregor GP

Abstract
Harpagophytum procumbens (Hp) is often used in the supportive treatment of inflammatory and degenerative diseases of the skeletal system. Although the clinical efficacy in osteoarthritis has been demonstrated in clinical trials, the molecular target(s) of Hp are unclear. This study quantified the effects of the ethanol Hp extract (60% v/v ethanol, sole active ingredient of Pascoe�-Agil), on the expression and release of the major pro-inflammatory mediators in LPS-stimulated human monocytes and the intracellular signalling pathways involved in inflammation. The Hp extract dose-dependently inhibited the release of TNF? as well as that of interleukin (IL)-6, IL-1? and prostaglandin E? (PGE?). The Hp prevented TNF? and IL-6 mRNA expression in human monocytes and cyclooxygenase-2 (COX-2) in RAW 264.7 cells. Furthermore, the Hp extract inhibited LPS-stimulated AP-1-mediated gene transcription activity and binding to the AP-1 response elements. The extract had no effect on the LPS-induced binding of nuclear factor-?B in RAW 264.7 cells, on LPS-induced degradation of I?B? or on LPS-induced activation of mitogen-activated protein kinases (MAPK), p38MAPK and JNK in human monocytes. The data indicate that a standardized ethanol Hp extract inhibits induction of pro-inflammatory gene expression, possibly by blocking the AP-1 pathway. This is novel evidence of a possible mechanism of action of this antiinflammatory drug.

PMID: 22072539 [PubMed - indexed for MEDLINE]

zm-447439 rad001 ecdysone

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]

Novel germline CDK4 mutations in patients with head and neck cancer.

Novel germline CDK4 mutations in patients with head and neck cancer.

Hered Cancer Clin Pract. 2012;10(1):11

Authors: Sabir M, Baig RM, Mahjabeen I, Kayani MA

PMID: 22932448 [PubMed - in process]

Aurora kinase family: a new target for anticancer drug.

Aurora kinase family: a new target for anticancer drug.

Recent Pat Anticancer Drug Discov. 2008 Jun;3(2):114-22

Authors: Macarulla T, Ramos FJ, Tabernero J

Abstract
Aurora kinases (AK) are the name given to a family of Serine/threonine (Ser/Thr) protein kinases. These proteins represent a novel family of kinases crucial for cell cycle control. The cell division process is one of the hallmarks of every living organism. Within the complete cell-cycle process, mitosis constitutes one of the most critical steps. The main purpose of mitosis is to segregate sister chromatics into two daughters cells. It is a complex biologic process, and errors in this mechanism can lead to genomic instability, a condition associated with tumorigenesis. This process is tightly regulated by several proteins, some of them acting as check-points that ultimately ensure the correct temporal and spatial coordination of this critical biologic process. Among this network of mitotic regulators, AK play a critical role in cellular division by controlling chromatid segregation. Three AK family members have been identified in mammalian cells: A, B, and C. These proteins are implicated in several vital events in mitosis. In experimental models, overexpression of AK can induce spindle defects, chromosome mis-segregation, and malignant transformation. Conversely, downregulation of AK expression cause mitotic arrest and apoptosis in tumor cell lines. The expression levels of human AK are increased in certain types of cancer including breast, colon, pancreatic, ovarian, and gastric tumors. This observation has lent an interest to this family of kinases as potential drug targets for development of new anticancer therapies. This review focuses in recent progress in the role of AK in tumorogenesis and the development of new anticancer drug against AK proteins. This manuscript also includes some relevant patents as well.

PMID: 18537754 [PubMed - indexed for MEDLINE]

2012年10月3日星期三

Celecoxib desensitization: continued temozolomide/celecoxib chemotherapy after a celecoxib-induced hypersensitivity reaction.

Celecoxib desensitization: continued temozolomide/celecoxib chemotherapy after a celecoxib-induced hypersensitivity reaction.

Anticancer Drugs. 2012 Nov;23(10):1118-1120

Authors: Burbach GJ, Vajkoczy P, Zuberbier T

Abstract
Cox-2 inhibitors have been identified as promising candidates for cancer therapy. Several studies have recently proposed the use of celecoxib in long-term low-intensity chemotherapy protocols for recurrent tumors. However, drug-induced hypersensitivity reactions may force discontinuation of the medication and, thus, significantly complicate successful care. Here, we report on celecoxib desensitization after a celecoxib-induced skin reaction, thereby allowing the continuation of temozolomide/celecoxib chemotherapy in a young patient with recurrent astrocytoma.

PMID: 23026982 [PubMed - as supplied by publisher]

Tyrosine kinase inhibitor insensitivity of non-cycling CD34+ human acute myeloid leukaemia cells with FMS-like tyrosine kinase 3 mutations.

Tyrosine kinase inhibitor insensitivity of non-cycling CD34+ human acute myeloid leukaemia cells with FMS-like tyrosine kinase 3 mutations.

Br J Haematol. 2011 Aug;154(4):457-65

Authors: Alvares CL, Schenk T, Hulkki S, Min T, Vijayaraghavan G, Yeung J, Gonzalez D, So CW, Greaves M, Titley I, Bartolovic K, Morgan G

Abstract
The efficacy of tyrosine kinase (TK) inhibitors on non-cycling acute myeloid leukaemia (AML) cells, previously shown to have potent tumourigenic potential, is unknown. This pilot study describes the first attempt to characterize non-cycling cells from a small series of human FMS-like tyrosine kinase 3 (FLT3) mutation positive samples. CD34+ AML cells from patients with FLT3 mutation positive AML were cultured on murine stroma. In expansion cultures, non-cycling cells were found to retain CD34+ expression in contrast to dividing cells. Leukaemic gene rearrangements could be detected in non-cycling cells, indicating their leukaemic origin. Significantly, the FLT3-internal tandem duplication (ITD) mutation was found in the non-cycling fraction of four out of five cases. Exposure to the FLT3-directed inhibitor TKI258 clearly inhibited the growth of AML CD34+ cells in short-term cultures and colony-forming unit assays. Crucially, non-cycling cells were not eradicated, with the exception of one case, which exhibited exquisite sensitivity to the compound. Moreover, in longer-term cultures, TKI258-treated non-cycling cells showed no growth impairment compared to treatment-naive non-cycling cells. These findings suggest that non-cycling cells in AML may constitute a disease reservoir that is resistant to TK inhibition. Further studies with a larger sample size and other inhibitors are warranted.

PMID: 21689085 [PubMed - indexed for MEDLINE]

Pyridofuran substituted pyrimidine derivatives as HCV replication (replicase) inhibitors.

Pyridofuran substituted pyrimidine derivatives as HCV replication (replicase) inhibitors.

Bioorg Med Chem Lett. 2012 Aug 1;22(15):5144-9

Authors: Bennett F, Kezar HS, Girijavallabhan V, Huang Y, Huelgas R, Rossman R, Shih NY, Piwinski JJ, MacCoss M, Kwong CD, Clark JL, Fowler AT, Geng F, Roychowdhury A, Reynolds RC, Maddry JA, Ananthan S, Secrist JA, Li C, Chase R, Curry S, Huang HC, Tong X, George Njoroge F, Arasappan A

Abstract
Introduction of nitrogen atom into the benzene ring of a previously identified HCV replication (replicase) benzofuran inhibitor 2, resulted in the discovery of the more potent pyridofuran analogue 5. Subsequent introduction of small alkyl and alkoxy ligands into the pyridine ring resulted in further improvements in replicon potency. Replacement of the 4-chloro moiety on the pyrimidine core with a methyl group, and concomitant monoalkylation of the C-2 amino moiety resulted in the identification of several inhibitors with desirable characteristics. Inhibitor 41, from the monosubstituted pyridofuran and inhibitor 50 from the disubstituted series displayed excellent potency, selectivity (GAPDH/MTS CC(50)) and PK parameters in all species studied, while the selectivity in the thymidine incorporation assay (DNA�CC(50)) was low.

PMID: 22814211 [PubMed - in process]

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]

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]

2012年10月2日星期二

FGFR inhibitor induced peripheral neuropathy in patients with advanced RCC.

FGFR inhibitor induced peripheral neuropathy in patients with advanced RCC.

Ann Oncol. 2010 Jul;21(7):1559-60

Authors: Loriot Y, Massard C, Angevin E, Lambotte O, Escudier B, Soria JC

PMID: 20444848 [PubMed - indexed for MEDLINE]

Aurora kinase family: a new target for anticancer drug.

Aurora kinase family: a new target for anticancer drug.

Recent Pat Anticancer Drug Discov. 2008 Jun;3(2):114-22

Authors: Macarulla T, Ramos FJ, Tabernero J

PMID: 18537754 [PubMed - indexed for MEDLINE]

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Preclinical stereoselective disposition and toxicokinetics of two novel MET inhibitors.

Preclinical stereoselective disposition and toxicokinetics of two novel MET inhibitors.

Xenobiotica. 2012 May;42(5):456-65

Authors: Liederer BM, Liu X, Berezhkovskiy LM, Cain G, Ding X, Gaudino J, Kaus R, Plise EG, Sutherlin DP, Harstad EB

Abstract
The R- and S-enantiomer of N-(4-(3-(1-ethyl-3,3-difluoropiperidin-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-4-yloxy)-3-fluorophenyl)-2-(4-fluorophenyl)-3-oxo-2,3-dihydropyridazine-4-carboxamide are novel MET kinase inhibitors that have been investigated as potential anticancer agents. The effect of the chirality of these compounds on preclinical in vivo pharmacokinetics and toxicity was studied. The plasma clearance for the S-enantiomer was low in mice and monkeys (23.7 and 7.8 mL min(-1) kg(-1), respectively) and high in rats (79.2 mL min(-1) kg(-1)). The R/S enantiomer clearance ratio was 1.5 except in rats (0.49). After oral single-dose administration at 5 mg kg(-1) the R/S enantiomer ratio of AUC(inf) was 0.95, 1.9 and 0.41 in mice, rats and monkeys, respectively. In an oral single-dose dose-ranging study at 200 and 500 mg kg(-1) and multi-dose toxicity study in mice plasma AUC exposure was approximately 2- to 3-fold higher for the R-enantiomer compared to the S-enantiomer. Greater toxicity of the S-enantiomer was observed which appeared to be due to high plasma C(min) values and tissue concentrations approximately 24 h after the final dose. Both enantiomers showed low to moderate permeability in MDCKI cells with no significant efflux, no preferential distribution into red blood cells and similar plasma protein binding in vitro. Overall, the differences between the enantiomers with respect to low dose pharmacokinetics and in vitro properties were relatively modest. However, toxicity results warrant further development of the R-enantiomer over the S-enantiomer.

PMID: 22122353 [PubMed - indexed for MEDLINE]

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]

A Critical Role for p130Cas in the Progression of Pulmonary Hypertension in Humans and Rodents.

A Critical Role for p130Cas in the Progression of Pulmonary Hypertension in Humans and Rodents.

Am J Respir Crit Care Med. 2012 Jul 12;

Authors: Tu L, De Man FS, Girerd B, Huertas A, Chaumais MC, Lecerf F, Fran�ois C, Perros F, Dorfm�ller P, Fadel E, Montani D, Eddahibi S, Humbert M, Guignabert C

Abstract
RATIONALE: Pulmonary arterial hypertension (PAH) is a progressive and fatal disease characterized by pulmonary arterial muscularization due to excessive pulmonary vascular cell proliferation and migration, a phenotype dependent upon growth factors and activation of receptor tyrosine kinases (RTKs). p130Cas is an adaptor protein involved in several cellular signaling pathways that control cell migration, proliferation and survival. OBJECTIVES: We hypothesized that in experimental and human PAH p130Cas signaling is over-activated, thereby facilitating the intracellular transmission of signal induced by fibroblast growth factor (FGF)-2, epidermal growth factor (EGF), and platelet-derived growth factor (PDGF). MEASUREMENTS AND MAIN RESULTS: In PAH patients, levels of p130Cas protein and/or activity are higher in the serum, in walls of distal pulmonary arteries, in cultured smooth muscle (PA-SMCs) and pulmonary endothelial cells (P-ECs) than controls. These abnormalities in the p130Cas signaling were also found to be in the chronically hypoxic mice and monocrotaline-injected rats as models of human PAH. We next obtained evidence for convergence and amplification of the growth-stimulating effect of EGF, FGF2 and PDGF signaling pathways via p130Cas signaling pathway. Finally, we found that daily treatment with each of the EGF-R inhibitor gefitinib, the FGF-R inhibitor dovitinib and the PDGF-R inhibitor imatinib started 2 weeks after a subcutaneous monocrotaline injection substantially attenuate the abnormal increase in p130cas and ERK1/2 activation and regress established PH. CONCLUSIONS: Our findings demonstrate that p130Cas signaling plays a critical role in experimental and iPAH by modulating pulmonary vascular cell migration, proliferation and by acting as an amplifier of RTKs downstream signals.

PMID: 22798315 [PubMed - as supplied by publisher]

2012年10月1日星期一

Treatment of everolimus-resistant metastatic renal cell carcinoma with VEGF-targeted therapies.

Treatment of everolimus-resistant metastatic renal cell carcinoma with VEGF-targeted therapies.

Br J Cancer. 2011 Nov 22;105(11):1635-9

Authors: Gr�nwald V, Seidel C, Fenner M, Ganser A, Busch J, Weikert S

Abstract
BACKGROUND: Treatment of everolimus-resistant disease remains largely undefined in metastatic renal cell carcinoma (mRCC). We report on 40 patients (pts) who receive systemic treatment after failure of everolimus.
PATIENTS AND METHODS: Forty pts received sunitinib (n=19), sorafenib (n=8), dovitinib (n=10) or bevacizumab/interferon (n=3) after failure of everolimus. Median progression-free survival (PFS), overall survival (OS) and best tumour response (according to Response Evaluation Criteria In Solid Tumors) were analysed retrospectively. Kaplan-Meier, log-rank test and Cox regression analyses were used to estimate or predict OS and PFS.
RESULTS: Treatment of everolimus-resistant disease was associated with a PFS of 5.5 months. (range 0.4-22.3) and an objective partial remission (PR) in 4 pts (10%) and stable disease (SD) in 22 pts (55%). In univariate analyses, first-line treatment with sorafenib was the only variable to correlate with a prolonged PFS of treatment in everolimus-resistant disease (P=0.036). However, its significance as a predictive marker for subsequent therapy could not be verified in multivariate analyses.
CONCLUSIONS: Vascular endothelial growth factor targeted therapy shows promising activity in everolimus-resistant metastatic renal cancer and warrants further studies.

PMID: 22033275 [PubMed - indexed for MEDLINE]

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]

Downregulation of protein kinase CK2 induces autophagic cell death through modulation of the mTOR and MAPK signaling pathways in human glioblastoma cells.

Downregulation of protein kinase CK2 induces autophagic cell death through modulation of the mTOR and MAPK signaling pathways in human glioblastoma cells.

Int J Oncol. 2012 Sep 21;

Authors: Olsen BB, Svenstrup TH, Guerra B

Abstract
Glioblastoma multiforme is the most common primary brain tumor and one of the most aggressive types of cancer in adults. Survival signaling and apoptosis resistance are hallmarks of malignant glioma cells. However, recent studies have shown that other types of cell death such as autophagy can be induced in malignant glioma cells. This suggests that stimulation of this process may be explored in new therapeutic strategies against glioblastoma multiforme. Protein kinase CK2 is a highly conserved and constitutively active enzyme that promotes numerous cellular processes such as survival, proliferation and differentiation. CK2 has been found elevated in several malignancies including brain tumors, and to confer resistance against chemotherapeutic agents and apoptotic stimuli. Recently, we have shown that the siRNA-mediated downregulation of CK2 leads to cell death in DNA-PK-proficient human glioblastoma cells. We show, here, that lack of CK2 results in significant induction of autophagic cell death in two human glioblastoma cell lines, M059K and T98G, as indicated by the positive staining of cells with the acidotropic dye acridine orange, and the specific recruitment of microtubule-associated protein 1 light chain 3 (LC3) to autophagosome membranes. Induction of autophagy is accompanied by CK2-dependent decreased phosphorylation of p70 ribosomal S6 and AKT kinases and significantly reduced expression levels of Raptor. In contrast, phosphorylation and activity levels of ERK1/2 are enhanced suggesting an inhibition of the PI3K/AKT/mTORC1 and activation of the ERK1/2 pathways. Furthermore, siRNA-mediated silencing of CK2 results in increased mitochondrial superoxide production in both glioblastoma cell lines. However, mitochondrial reactive oxygen species release correlates with induction of autophagy only in T98G cells. Taken together, our findings identify CK2 as a novel component of the autophagic machinery and underline the potential of its downregulation to kill glioblastoma cells by overcoming the resistance to multiple anticancer agents.

PMID: 23007634 [PubMed - as supplied by publisher]

ZM447439, a novel promising aurora kinase inhibitor, provokes antiproliferative and proapoptotic effects alone and in combination with bio- and chemotherapeutic agents in gastroenteropancreatic neuroendocrine tumor cell lines.

ZM447439, a novel promising aurora kinase inhibitor, provokes antiproliferative and proapoptotic effects alone and in combination with bio- and chemotherapeutic agents in gastroenteropancreatic neuroendocrine tumor cell lines.

Neuroendocrinology. 2010;91(2):121-30

Authors: Georgieva I, Koychev D, Wang Y, Holstein J, Hopfenm�ller W, Zeitz M, Grabowski P

Abstract
Background: Therapeutic approaches to gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are still not satisfactory. A new direction in treatment options could be the novel aurora kinase inhibitor ZM447439, which was previously reported to interfere with the mitotic spindle integrity checkpoint and chromosome segregation, but does not interfere with other kinases when used up to 5 muM. Methods: We evaluated the antineoplastic effects of ZM447439 on growth and apoptosis of the GEP-NET cell lines BON, QGP-1 and MIP-101, representing the different malignant tumor types, using standard cell biological tests as crystal violet assays, caspase activation, DNA fragmentation and cell cycle analysis. Results: ZM447439 dose-dependently inhibited proliferation of all three cell lines with IC(50) values in the nanomolar to low micromolar range. Moreover, aurora kinase inhibition by ZM447439 potently induced apoptosis, which was accompanied by DNA fragmentation and caspase 3 and 7 activation. Furthermore, we observed cell cycle arrest at G(0)/G(1) phase as well as a block in G(2)/M transition. In addition, combined treatment with the chemotherapeutic agents streptozocin and cisplatin augmented significantly the antiproliferative effects of those agents. Conclusion: Aurora kinase inhibition by ZM447439 seems to be a promising new therapeutic approach in GEP-NETs, which should be evaluated in further clinical trials.

PMID: 19923785 [PubMed - indexed for MEDLINE]

2012年9月30日星期日

Feature Article: Heat shock protein 90? (HSP90?), a substrate and chaperone of DNA-PK necessary for the apoptotic response.

Feature Article: Heat shock protein 90? (HSP90?), a substrate and chaperone of DNA-PK necessary for the apoptotic response.

Proc Natl Acad Sci U S A. 2012 Aug 7;109(32):12866-72

Authors: Solier S, Kohn KW, Scroggins B, Xu W, Trepel J, Neckers L, Pommier Y

Abstract
The "apoptotic ring" is characterized by the phosphorylation of histone H2AX at serine 139 (?-H2AX) by DNA-dependent protein kinase (DNA-PK). The ?-H2AX apoptotic ring differs from the nuclear foci patterns observed in response to DNA-damaging agents. It contains phosphorylated DNA damage response proteins including activated Chk2, activated ATM, and activated DNA-PK itself but lacks MDC1 and 53BP1, which are required to initiate DNA repair. Because DNA-PK can phosphorylate heat shock protein 90? (HSP90?) in biochemical assays, we investigated whether HSP90? is involved in the apoptotic ring. Here we show that HSP90? is phosphorylated by DNA-PK on threonines 5 and 7 early during apoptosis and that both phosphorylated HSP90? and DNA-PK colocalize in the apoptotic ring. We also show that DNA-PK is a client of HSP90? and that HSP90? is required for full DNA-PK activation, ?-H2AX formation, DNA fragmentation, and apoptotic body formation. In contrast, HSP90 inhibition by geldanamycin markedly enhances TRAIL-induced DNA-PK and H2AX activation. Together, our results reveal that HSP90? is a substrate and chaperone of DNA-PK in the apoptotic response. The response of phosphorylated HSP90? to TRAIL and its localization to the ?-H2AX ring represent epigenetic features of apoptosis that offer insights for studying and monitoring nuclear apoptosis.

PMID: 22753480 [PubMed - in process]

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]

Aurora kinase B modulates chromosome alignment in mouse oocytes.

Aurora kinase B modulates chromosome alignment in mouse oocytes.

Mol Reprod Dev. 2009 Nov;76(11):1094-105

Authors: Shuda K, Schindler K, Ma J, Schultz RM, Donovan PJ

Abstract
The elevated incidence of aneuploidy in human oocytes warrants study of the molecular mechanisms regulating proper chromosome segregation. The Aurora kinases are a well-conserved family of serine/threonine kinases that are involved in proper chromosome segregation during mitosis and meiosis. Here we report the expression and localization of all three Aurora kinase homologs, AURKA, AURKB, and AURKC, during meiotic maturation of mouse oocytes. AURKA, the most abundantly expressed homolog, localizes to the spindle poles during meiosis I (MI) and meiosis II (MII), whereas AURKB is concentrated at kinetochores, specifically at metaphase of MI (Met I). The germ cell-specific homolog, AURKC, is found along the entire length of chromosomes during both meiotic divisions. Maturing oocytes in the presence of the small molecule pan-Aurora kinase inhibitor, ZM447439 results in defects in meiotic progression and chromosome alignment at both Met I and Met II. Over-expression of AURKB, but not AURKA or AURKC, rescues the chromosome alignment defect suggesting that AURKB is the primary Aurora kinase responsible for regulating chromosome dynamics during meiosis in mouse oocytes.

PMID: 19565641 [PubMed - indexed for MEDLINE]

Naringenin attenuates the release of pro-inflammatory mediators from lipopolysaccharide-stimulated BV2 microglia by inactivating nuclear factor-?B and inhibiting mitogen-activated protein kinases.

Int J Mol Med. 2012 Jul;30(1):204-10

Authors: Park HY, Kim GY, Choi YH

Abstract
Naringenin, one of the most abundant flavonoids in citrus fruits and grapefruits, has been reported to exhibit anti-inflammatory and antitumor activities. However, the cellular and molecular mechanisms underlying the naringenin anti-inflammatory activity are poorly understood. In this study, we conducted an investigation of the inhibitory effects of naringenin on the production of lipopolysaccharide (LPS)-induced pro-inflammatory mediators in BV2 microglial cells. We found that pre-treatment with naringenin prior to treatment with LPS significantly inhibited excessive production of nitric oxide (NO) and prostaglandin E2 (PGE2) in a dose-dependent manner. The inhibition was associated with downregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. Naringenin also attenuated the production of pro-inflammatory cytokines and chemokines, including interleukin-1? (IL-1?), tumor necrosis factor-? (TNF-?) and monocyte chemoattractant protein-1 (MCP-1) by suppressing expression of mRNAs for these proteins. In addition, the molecular mechanism underlying naringenin-mediated attenuation in BV2 cells has a close relationship to suppressing translocation of the nuclear factor-?B (NF-?B) p65 subunit into the nucleus and the phosphorylation of Akt and mitogen-activated protein kinases (MAPKs). These findings suggest that naringenin may provide neuroprotection through suppression of pro-inflammatory pathways in activated BV2 microglial cells.

PMID: 22552813 [PubMed - indexed for MEDLINE]

Aurora B couples chromosome alignment with anaphase by targeting BubR1, Mad2, and Cenp-E to kinetochores.

Aurora B couples chromosome alignment with anaphase by targeting BubR1, Mad2, and Cenp-E to kinetochores.

J Cell Biol. 2003 Apr 28;161(2):267-80

Authors: Ditchfield C, Johnson VL, Tighe A, Ellston R, Haworth C, Johnson T, Mortlock A, Keen N, Taylor SS

Abstract
The Aurora/Ipl1 family of protein kinases plays multiple roles in mitosis and cytokinesis. Here, we describe ZM447439, a novel selective Aurora kinase inhibitor. Cells treated with ZM447439 progress through interphase, enter mitosis normally, and assemble bipolar spindles. However, chromosome alignment, segregation, and cytokinesis all fail. Despite the presence of maloriented chromosomes, ZM447439-treated cells exit mitosis with normal kinetics, indicating that the spindle checkpoint is compromised. Indeed, ZM447439 prevents mitotic arrest after exposure to paclitaxel. RNA interference experiments suggest that these phenotypes are due to inhibition of Aurora B, not Aurora A or some other kinase. In the absence of Aurora B function, kinetochore localization of the spindle checkpoint components BubR1, Mad2, and Cenp-E is diminished. Furthermore, inhibition of Aurora B kinase activity prevents the rebinding of BubR1 to metaphase kinetochores after a reduction in centromeric tension. Aurora B kinase activity is also required for phosphorylation of BubR1 on entry into mitosis. Finally, we show that BubR1 is not only required for spindle checkpoint function, but is also required for chromosome alignment. Together, these results suggest that by targeting checkpoint proteins to kinetochores, Aurora B couples chromosome alignment with anaphase onset.

PMID: 12719470 [PubMed - indexed for MEDLINE]