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Biomedicine. Rare cancer successes spawn 'exceptional' research efforts.
Science. 2013 Apr 19;340(6130):263
Authors: Kaiser J
PMID: 23599454 [PubMed - indexed for MEDLINE]
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Ataxia telangiectasia mutated (ATM) is dispensable for endonuclease I-SceI-induced homologous recombination in mouse embryonic stem cells.
J Biol Chem. 2013 Mar 8;288(10):7086-95
Authors: Rass E, Chandramouly G, Zha S, Alt FW, Xie A
Abstract
Ataxia telangiectasia mutated (ATM) is activated upon DNA double strand breaks (DSBs) and phosphorylates numerous DSB response proteins, including histone H2AX on serine 139 (Ser-139) to form ?-H2AX. Through interaction with MDC1, ?-H2AX promotes DSB repair by homologous recombination (HR). H2AX Ser-139 can also be phosphorylated by DNA-dependent protein kinase catalytic subunit and ataxia telangiectasia- and Rad3-related kinase. Thus, we tested whether ATM functions in HR, particularly that controlled by ?-H2AX, by comparing HR occurring at the euchromatic ROSA26 locus between mouse embryonic stem cells lacking either ATM, H2AX, or both. We show here that loss of ATM does not impair HR, including H2AX-dependent HR, but confers sensitivity to inhibition of poly(ADP-ribose) polymerases. Loss of ATM or H2AX has independent contributions to cellular sensitivity to ionizing radiation. The ATM-independent HR function of H2AX requires both Ser-139 phosphorylation and ?-H2AX/MDC1 interaction. Our data suggest that ATM is dispensable for HR, including that controlled by H2AX, in the context of euchromatin, excluding the implication of such an HR function in genomic instability, hypersensitivity to DNA damage, and poly(ADP-ribose) polymerase inhibition associated with ATM deficiency.
PMID: 23355489 [PubMed - indexed for MEDLINE]
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Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.
Transfusion. 2012 Nov;52(11):2406-13
Authors: Avanzi MP, Chen A, He W, Mitchell WB
Abstract
BACKGROUND: Large-scale in vitro production of platelets (PLTs) from cord blood stem cells is one goal of stem cell research. One step toward this goal will be to produce polyploid megakaryocytes capable of releasing high numbers of PLTs. Megakaryocyte polyploidization requires distinct cytoskeletal and cellular mechanisms, including actin polymerization, myosin activation, microtubule formation, and increased DNA production. In this study we variably combined inhibition of these principal mechanisms of cytokinesis with the goal of driving polyploidization in megakaryocytes.
STUDY DESIGN AND METHODS: Megakaryocytes were derived from umbilical cord blood and cultured with reagents that inhibit distinct mechanisms of cytokinesis: Rho-Rock inhibitor (RRI), Src inhibitor (SI), nicotinamide (NIC), aurora B inhibitor (ABI), and myosin light chain kinase inhibitor (MLCKI). Combinations of reagents were used to determine their interactions and to maximize megakaryocyte ploidy.
RESULTS: Treatment with RRI, NIC, SI, and ABI, but not with MLCKI, increased the final ploidy and RRI was the most effective single reagent. RRI and MLCKI, both inhibitors of MLC activation, resulted in opposite ploidy outcomes. Combinations of reagents also increased ploidy and the use of NIC, SI, and ABI was as effective as RRI alone. Addition of MLCKI to NIC, SI, and ABI reached the highest level of polyploidization.
CONCLUSION: Megakaryocyte polyploidization results from modulation of a combination of distinct cytokinesis pathways. Reagents targeting distinct cytoskeletal pathways produced additive effects in final megakaryocyte ploidy. The RRI, however, showed no additive effect but produced a high final ploidy due to overlapping inhibition of multiple cytokinesis pathways.
PMID: 22612069 [PubMed - indexed for MEDLINE]
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Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.
Transfusion. 2012 Nov;52(11):2406-13
Authors: Avanzi MP, Chen A, He W, Mitchell WB
Abstract
BACKGROUND: Large-scale in vitro production of platelets (PLTs) from cord blood stem cells is one goal of stem cell research. One step toward this goal will be to produce polyploid megakaryocytes capable of releasing high numbers of PLTs. Megakaryocyte polyploidization requires distinct cytoskeletal and cellular mechanisms, including actin polymerization, myosin activation, microtubule formation, and increased DNA production. In this study we variably combined inhibition of these principal mechanisms of cytokinesis with the goal of driving polyploidization in megakaryocytes.
STUDY DESIGN AND METHODS: Megakaryocytes were derived from umbilical cord blood and cultured with reagents that inhibit distinct mechanisms of cytokinesis: Rho-Rock inhibitor (RRI), Src inhibitor (SI), nicotinamide (NIC), aurora B inhibitor (ABI), and myosin light chain kinase inhibitor (MLCKI). Combinations of reagents were used to determine their interactions and to maximize megakaryocyte ploidy.
RESULTS: Treatment with RRI, NIC, SI, and ABI, but not with MLCKI, increased the final ploidy and RRI was the most effective single reagent. RRI and MLCKI, both inhibitors of MLC activation, resulted in opposite ploidy outcomes. Combinations of reagents also increased ploidy and the use of NIC, SI, and ABI was as effective as RRI alone. Addition of MLCKI to NIC, SI, and ABI reached the highest level of polyploidization.
CONCLUSION: Megakaryocyte polyploidization results from modulation of a combination of distinct cytokinesis pathways. Reagents targeting distinct cytoskeletal pathways produced additive effects in final megakaryocyte ploidy. The RRI, however, showed no additive effect but produced a high final ploidy due to overlapping inhibition of multiple cytokinesis pathways.
PMID: 22612069 [PubMed - indexed for MEDLINE]
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Inhibition of cyclooxygenase-2 reduces hypothalamic excitation in rats with adriamycin-induced heart failure.
PLoS One. 2012;7(11):e48771
Authors: Zheng M, Kang YM, Liu W, Zang WJ, Bao CY, Qin DN
Abstract
BACKGROUND: The paraventricular nucleus (PVN) of the hypothalamus plays an important role in the progression of heart failure (HF). We investigated whether cyclooxygenase-2 (COX-2) inhibition in the PVN attenuates the activities of sympathetic nervous system (SNS) and renin-angiotensin system (RAS) in rats with adriamycin-induced heart failure.
METHODOLOGY/PRINCIPAL FINDING: Heart failure was induced by intraperitoneal injection of adriamycin over a period of 2 weeks (cumulative dose of 15 mg/kg). On day 19, rats received intragastric administration daily with either COX-2 inhibitor celecoxib (CLB) or normal saline. Treatment with CLB reduced mortality and attenuated both myocardial atrophy and pulmonary congestion in HF rats. Compared with the HF rats, ventricle to body weight (VW/BW) and lung to body weight (LW/BW) ratios, heart rate (HR), left ventricular end-diastolic pressure (LVEDP), left ventricular peak systolic pressure (LVPSP) and maximum rate of change in left ventricular pressure (LV�dp/dtmax) were improved in HF+CLB rats. Angiotensin II (ANG II), norepinephrine (NE), COX-2 and glutamate (Glu) in the PVN were increased in HF rats. HF rats had higher levels of ANG II and NE in plasma, higher level of ANG II in myocardium, and lower levels of ANP in plasma and myocardium. Treatment with CLB attenuated these HF-induced changes. HF rats had more COX-2-positive neurons and more corticotropin releasing hormone (CRH) positive neurons in the PVN than did control rats. Treatment with CLB decreased COX-2-positive neurons and CRH positive neurons in the PVN of HF rats.
CONCLUSIONS: These results suggest that PVN COX-2 may be an intermediary step for PVN neuronal activation and excitatory neurotransmitter release, which further contributes to sympathoexcitation and RAS activation in adriamycin-induced heart failure. Treatment with COX-2 inhibitor attenuates sympathoexcitation and RAS activation in adriamycin-induced heart failure.
PMID: 23152801 [PubMed - indexed for MEDLINE]
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Association between efavirenz-based compared with nevirapine-based antiretroviral regimens and virological failure in HIV-infected children.
JAMA. 2013 May 1;309(17):1803-9
Authors: Lowenthal ED, Ellenberg JH, Machine E, Sagdeo A, Boiditswe S, Steenhoff AP, Rutstein R, Anabwani G, Gross R
Abstract
IMPORTANCE: Worldwide, the nonnucleoside reverse transcriptase inhibitors (NNRTIs) efavirenz and nevirapine are commonly used in first-line antiretroviral regimens in both adults and children with human immunodeficiency virus (HIV) infection. Data on the comparative effectiveness of these medications in children are limited.
OBJECTIVE: To investigate whether virological failure is more likely among children who initiated 1 or the other NNRTI-based HIV treatment.
DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study of children (aged 3-16 years) who initiated efavirenz-based (n = 421) or nevirapine-based (n = 383) treatment between April 2002 and January 2011 at a large pediatric HIV care setting in Botswana. MAIN OUTCOMES AND MEASURES: The primary outcome was time from initiation of therapy to virological failure. Virological failure was defined as lack of plasma HIV RNA suppression to less than 400 copies/mL by 6 months or confirmed HIV RNA of 400 copies/mL or greater after suppression. Cox proportional hazards regression analysis compared time to virological failure by regimen. Multivariable Cox regression controlled for age, sex, baseline immunologic category, baseline clinical category, baseline viral load, nutritional status, NRTIs used, receipt of single-dose nevirapine, and treatment for tuberculosis.
RESULTS: With a median follow-up time of 69 months (range, 6-112 months; interquartile range, 23-87 months), 57 children (13.5%; 95% CI, 10.4%-17.2%) initiating treatment with efavirenz and 101 children (26.4%; 95% CI, 22.0%-31.1%) initiating treatment with nevirapine had virological failure. There were 11 children (2.6%; 95% CI, 1.3%-4.6%) receiving efavirenz and 20 children (5.2%; 95% CI, 3.2%-7.9%) receiving nevirapine who never achieved virological suppression. The Cox proportional hazard ratio for the combined virological failure end point was 2.0 (95% CI, 1.4-2.7; log rank P < .001, favoring efavirenz). None of the measured covariates affected the estimated hazard ratio in the multivariable analyses.
CONCLUSIONS AND RELEVANCE: Among children aged 3 to 16 years infected with HIV and treated at a clinic in Botswana, the use of efavirenz compared with nevirapine as initial antiretroviral treatment was associated with less virological failure. These findings may warrant additional research evaluating the use of efavirenz and nevirapine for pediatric patients.
PMID: 23632724 [PubMed - in process]
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The human Lgl polarity gene, Hugl-2, induces MET and suppresses Snail tumorigenesis.
Oncogene. 2013 Mar 14;32(11):1396-407
Authors: Kashyap A, Zimmerman T, Erg�l N, Bosserhoff A, Hartman U, Alla V, Bataille F, Galle PR, Strand S, Strand D
Abstract
Lethal giant larvae proteins have key roles in regulating polarity in a variety of cell types and function as tumour suppressors. A transcriptional programme initiated by aberrant Snail expression transforms epithelial cells to potentially aggressive cancer cells. Although progress in defining the molecular determinants of this programme has been made, we have little knowledge as to how the Snail-induced phenotype can be suppressed. In our studies we identified the human lethal giant larvae homologue 2, Hugl-2, (Llgl2/Lgl2) polarity gene as downregulated by Snail. Snail binds E-boxes in the Hugl-2 promoter and represses Hugl-2 expression, whereas removal of the E-boxes releases Hugl-2 from Snail repression. We demonstrate that inducing Hugl-2 in cells with constitutive Snail expression reverses the phenotype including changes in morphology, motility, tumour growth and dissemination in vivo, and expression of epithelial markers. Hugl-2 expression reduced the nuclear localization of Snail and thus binding of Snail to its target promoters. Our results placing Hugl-2 within the Snail network as well as its ability to suppress Snail carcinogenesis identifies Hugl-2 as a target molecule driving cascades, which may have preventative and therapeutic promise to minimize cancer progression.
PMID: 22580609 [PubMed - indexed for MEDLINE]
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Inhibition of cyclooxygenase-2 reduces hypothalamic excitation in rats with adriamycin-induced heart failure.
PLoS One. 2012;7(11):e48771
Authors: Zheng M, Kang YM, Liu W, Zang WJ, Bao CY, Qin DN
Abstract
BACKGROUND: The paraventricular nucleus (PVN) of the hypothalamus plays an important role in the progression of heart failure (HF). We investigated whether cyclooxygenase-2 (COX-2) inhibition in the PVN attenuates the activities of sympathetic nervous system (SNS) and renin-angiotensin system (RAS) in rats with adriamycin-induced heart failure.
METHODOLOGY/PRINCIPAL FINDING: Heart failure was induced by intraperitoneal injection of adriamycin over a period of 2 weeks (cumulative dose of 15 mg/kg). On day 19, rats received intragastric administration daily with either COX-2 inhibitor celecoxib (CLB) or normal saline. Treatment with CLB reduced mortality and attenuated both myocardial atrophy and pulmonary congestion in HF rats. Compared with the HF rats, ventricle to body weight (VW/BW) and lung to body weight (LW/BW) ratios, heart rate (HR), left ventricular end-diastolic pressure (LVEDP), left ventricular peak systolic pressure (LVPSP) and maximum rate of change in left ventricular pressure (LV�dp/dtmax) were improved in HF+CLB rats. Angiotensin II (ANG II), norepinephrine (NE), COX-2 and glutamate (Glu) in the PVN were increased in HF rats. HF rats had higher levels of ANG II and NE in plasma, higher level of ANG II in myocardium, and lower levels of ANP in plasma and myocardium. Treatment with CLB attenuated these HF-induced changes. HF rats had more COX-2-positive neurons and more corticotropin releasing hormone (CRH) positive neurons in the PVN than did control rats. Treatment with CLB decreased COX-2-positive neurons and CRH positive neurons in the PVN of HF rats.
CONCLUSIONS: These results suggest that PVN COX-2 may be an intermediary step for PVN neuronal activation and excitatory neurotransmitter release, which further contributes to sympathoexcitation and RAS activation in adriamycin-induced heart failure. Treatment with COX-2 inhibitor attenuates sympathoexcitation and RAS activation in adriamycin-induced heart failure.
PMID: 23152801 [PubMed - indexed for MEDLINE]
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Cell Cycle Abnormalities Associated with Differential Perturbations of the Human U5 snRNP Associated U5-200kD RNA Helicase.
PLoS One. 2013;8(4):e62125
Authors: Ehsani A, Alluin JV, Rossi JJ
Abstract
Splicing of pre-messenger RNAs into functional messages requires a concerted assembly of proteins and small RNAs that identify the splice junctions and facilitate cleavage of exon-intron boundaries and ligation of exons. One of the key steps in the splicing reaction is the recruitment of a tri-snRNP harboring the U5/U4/U6 snRNPs. The U5 snRNP is also required for both steps of splicing and exon-exon joining. One of the key components of the tri-snRNP is the U5 200kd helicase. The human U5-200kD gene isolated from Hela cells encodes a 200 kDa protein with putative RNA helicase function. Surprisingly, little is known about the functional role of this protein in humans. Therefore, we have investigated the role of the U5-200kD RNA helicase in mammalian cell culture. We created and expressed a dominant negative domain I mutant of the RNA helicase in HEK293 cells and used RNAi to downregulate expression of the endogenous protein. Transient and stable expression of the domain I mutant U5-200kD protein using an ecdysone-inducible system and transient expression of an anti-U5-200kD short hairpin RNA (shRNA) resulted in differential splicing and growth defects in the 293/EcR cells. Cell cycle analysis of the dominant negative clones revealed delayed exit from the G2/M phase of the cell cycle due to a mild splicing defect. In contrast to the domain I dominant negative mutant expressing cells, transient expression of an anti-U5-200kD shRNA resulted in a pronounced S phase arrest and a minute splicing defect. Collectively, this work demonstrates for the first time establishment of differential human cell culture splicing and cell cycle defect models due to perturbed levels of an essential core splicing factor.
PMID: 23637979 [PubMed - in process]
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The progression free survival-plateau with vascular endothelial growth factor receptor inhibitors - Is there more to come?
Eur J Cancer. 2013 Apr 16;
Authors: Gr�nwald V, Merseburger AS
Abstract
The field of renal cell carcinoma (RCC) treatment has changed dramatically during recent years. Sunitinib, sorafenib and pazopanib were the first generation of vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs) to have significant clinical activity in metastatic clear cell RCC. These TKI share inhibition of VEGFR family members, but differ in their ability to block other cellular kinases. Axitinib and tivozanib are 2nd generation TKIs, which show high specificity for VEGFR inhibition and exert a favourable toxicity profile. Both agents have succeeded in pivotal clinical trials, which were the first studies to compare two distinct TKIs. Progression free survival (PFS) shows an advantage for the 2nd generation TKIs, but also curbs enthusiasm for limitless PFS expectations with a PFS plateau of 13-14months in 1st line treatment. More recently, novel targets have gained attention in RCC, such as the mesenchymal epithelial transition factor also known as the MET receptor and the fibroblast growth factor receptor (FGFR). These receptors are included into the inhibitory profiles of third generation TKIs such as cabozantinib or dovitinib, which showed promising activity in early clinical trials. Randomised controlled trials explore the role of these agents, and whether the expansion of targets inhibited may lead to more effective treatments in RCC.
PMID: 23601669 [PubMed - as supplied by publisher]
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Image-based high-throughput screening for inhibitors of angiogenesis.
Methods Mol Biol. 2013;931:139-51
Authors: Evensen L, Link W, Lorens JB
Abstract
Automated multicolor fluorescence microscopy facilitates high-throughput quantitation of cellular parameters of complex, organotypic systems. In vitro co-cultured vascular cells form capillary-like networks that model facets of angiogenesis, making it an attractive alternative for anti-angiogenic drug discovery. We have adapted this angiogenesis assay system to a high-throughput format to enable automated image-based high-throughput screening of live primary human vascular cell co-cultures with chemical libraries for anti-angiogenic drug discovery. Protocols are described for setup of a fluorescence-based co-culture assay, live cell image acquisition, image analysis of morphological parameters, and screening data handling.
PMID: 23027002 [PubMed - indexed for MEDLINE]
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The edge vascular response following implantation of the Absorb everolimus-eluting bioresorbable vascular scaffold and the XIENCE V metallic everolimus-eluting stent. First serial follow-up assessment at six months and two years: insights from the first-in-man ABSORB Cohort B and SPIRIT II trials.
EuroIntervention. 2013 Apr 30;
Authors: Gogas BD, Bourantas CV, Garcia-Garcia HM, Onuma Y, Muramatsu T, Farooq V, Diletti R, van Geuns RJ, De Bruyne B, Chevalier B, Thuesen L, Smits PC, Dudek D, Koolen J, Windecker S, Whitbourn R, McClean D, Dorange C, Miquel-Hebert K, Veldhof S, Rapoza R, Ormiston JA, Serruys PW
Abstract
Aims: To assess serially the edge vascular response (EVR) of a bioresorbable vascular scaffold (BVS) compared to a metallic everolimus-eluting stent (EES). Methods and results: Non-serial evaluations of the Absorb BVS at one year have previously demonstrated proximal edge constrictive remodelling and distal edge changes in plaque composition with increase of the percent fibro-fatty (FF) tissue component. The 5 mm proximal and distal segments adjacent to the implanted devices were investigated serially with intravascular ultrasound (IVUS), post procedure, at six months and at two years, from the ABSORB Cohort B1 (n=45) and the SPIRIT II (n=113) trials. Twenty-two proximal and twenty-four distal edge segments were available for analysis in the ABSORB Cohort B1 trial. In the SPIRIT II trial, thirty-three proximal and forty-six distal edge segments were analysed. At the 5-mm proximal edge, the vessels treated with an Absorb BVS from post procedure to two years demonstrated a lumen loss (LL) of 6.68% (-17.33; 2.08) (p=0.027) with a trend toward plaque area increase of 7.55% (-4.68; 27.11) (p=0.06). At the 5-mm distal edge no major changes were evident at either time point. At the 5-mm proximal edge the vessels treated with a XIENCE V EES from post procedure to two years did not show any signs of LL, only plaque area decrease of 6.90% (-17.86; 4.23) (p=0.035). At the distal edge no major changes were evident with regard to either lumen area or vessel remodelling at the same time point. Conclusions: The IVUS-based serial evaluation of the EVR up to two years following implantation of a bioresorbable everolimus-eluting scaffold shows a statistically significant proximal edge LL; however, this finding did not seem to have any clinical implications in the serial assessment. The upcoming imaging follow-up of the Absorb BVS at three years is anticipated to provide further information regarding the vessel wall behaviour at the edges.
PMID: 23628499 [PubMed - as supplied by publisher]
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Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.
Transfusion. 2012 Nov;52(11):2406-13
Authors: Avanzi MP, Chen A, He W, Mitchell WB
Abstract
BACKGROUND: Large-scale in vitro production of platelets (PLTs) from cord blood stem cells is one goal of stem cell research. One step toward this goal will be to produce polyploid megakaryocytes capable of releasing high numbers of PLTs. Megakaryocyte polyploidization requires distinct cytoskeletal and cellular mechanisms, including actin polymerization, myosin activation, microtubule formation, and increased DNA production. In this study we variably combined inhibition of these principal mechanisms of cytokinesis with the goal of driving polyploidization in megakaryocytes.
STUDY DESIGN AND METHODS: Megakaryocytes were derived from umbilical cord blood and cultured with reagents that inhibit distinct mechanisms of cytokinesis: Rho-Rock inhibitor (RRI), Src inhibitor (SI), nicotinamide (NIC), aurora B inhibitor (ABI), and myosin light chain kinase inhibitor (MLCKI). Combinations of reagents were used to determine their interactions and to maximize megakaryocyte ploidy.
RESULTS: Treatment with RRI, NIC, SI, and ABI, but not with MLCKI, increased the final ploidy and RRI was the most effective single reagent. RRI and MLCKI, both inhibitors of MLC activation, resulted in opposite ploidy outcomes. Combinations of reagents also increased ploidy and the use of NIC, SI, and ABI was as effective as RRI alone. Addition of MLCKI to NIC, SI, and ABI reached the highest level of polyploidization.
CONCLUSION: Megakaryocyte polyploidization results from modulation of a combination of distinct cytokinesis pathways. Reagents targeting distinct cytoskeletal pathways produced additive effects in final megakaryocyte ploidy. The RRI, however, showed no additive effect but produced a high final ploidy due to overlapping inhibition of multiple cytokinesis pathways.
PMID: 22612069 [PubMed - indexed for MEDLINE]
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Mepivacaine-induced contraction involves phosphorylation of extracellular signal-regulated kinase through activation of the lipoxygenase pathway in isolated rat aortic smooth muscle.
Can J Physiol Pharmacol. 2013 Apr;91(4):285-94
Authors: Lee HM, Ok SH, Sung HJ, Eun SY, Kim HJ, Lee SH, Kang S, Shin IW, Lee HK, Chung YK, Choi MJ, Bae SI, Sohn JT
Abstract
Mepivacaine is an aminoamide local anesthetic with an intermediate duration that intrinsically produces vasoconstriction both in vivo and in vitro. This study investigated the arachidonic acid metabolic pathways involved in mepivacaine-induced contraction, and elucidated the associated cellular mechanism with a particular focus on extracellular signal-regulated kinase (ERK) in endothelium-denuded rat aorta. Isolated rat thoracic aortic rings were suspended for isometric tension recording. Cumulative mepivacaine concentration-response curves were generated in the presence or absence of the following inhibitors: quinacrine dihydrochloride, nordihydroguaiaretic acid, phenidone, AA-861, indomethacin, NS-398, SC-560, fluconazole, PD 98059, and verapamil. Mepivacaine-induced ERK phosphorylation, 5-lipoxygenase (5-LOX) expression, and cyclooxygenase (COX)-2 expression in rat aortic smooth muscle cells were detected by Western blot analysis in the presence or absence of inhibitors. Mepivacaine produced tonic contraction in isolated endothelium-denuded rat aorta. Quinacrine dihydrochloride, nordihydroguaiaretic acid, phenidone, AA-861, NS-398, PD 98059, and verapamil attenuated mepivacaine-induced contraction in a concentration-dependent manner. However, fluconazole had no effect on mepivacaine-induced contraction. PD 98059, quinacrine dihydrochloride, nordihydroguaiaretic acid, AA-861, phenidone, and indomethacin attenuated mepivacaine-induced ERK phosphorylation. Mepivacaine upregulated 5-LOX and COX-2 expression. These results suggest that mepivacaine-induced contraction involves ERK activation, which is primarily mediated by the 5-LOX pathway and in part by the COX-2 pathway.
PMID: 23627840 [PubMed - in process]
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Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.
Transfusion. 2012 Nov;52(11):2406-13
Authors: Avanzi MP, Chen A, He W, Mitchell WB
Abstract
BACKGROUND: Large-scale in vitro production of platelets (PLTs) from cord blood stem cells is one goal of stem cell research. One step toward this goal will be to produce polyploid megakaryocytes capable of releasing high numbers of PLTs. Megakaryocyte polyploidization requires distinct cytoskeletal and cellular mechanisms, including actin polymerization, myosin activation, microtubule formation, and increased DNA production. In this study we variably combined inhibition of these principal mechanisms of cytokinesis with the goal of driving polyploidization in megakaryocytes.
STUDY DESIGN AND METHODS: Megakaryocytes were derived from umbilical cord blood and cultured with reagents that inhibit distinct mechanisms of cytokinesis: Rho-Rock inhibitor (RRI), Src inhibitor (SI), nicotinamide (NIC), aurora B inhibitor (ABI), and myosin light chain kinase inhibitor (MLCKI). Combinations of reagents were used to determine their interactions and to maximize megakaryocyte ploidy.
RESULTS: Treatment with RRI, NIC, SI, and ABI, but not with MLCKI, increased the final ploidy and RRI was the most effective single reagent. RRI and MLCKI, both inhibitors of MLC activation, resulted in opposite ploidy outcomes. Combinations of reagents also increased ploidy and the use of NIC, SI, and ABI was as effective as RRI alone. Addition of MLCKI to NIC, SI, and ABI reached the highest level of polyploidization.
CONCLUSION: Megakaryocyte polyploidization results from modulation of a combination of distinct cytokinesis pathways. Reagents targeting distinct cytoskeletal pathways produced additive effects in final megakaryocyte ploidy. The RRI, however, showed no additive effect but produced a high final ploidy due to overlapping inhibition of multiple cytokinesis pathways.
PMID: 22612069 [PubMed - indexed for MEDLINE]
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Long-term use of antiplatelet drugs by stroke patients: a follow-up study based on prescription register data.
Eur J Clin Pharmacol. 2012 Dec;68(12):1631-7
Authors: �stergaard K, Hallas J, Bak S, Christensen Rd, Gaist D
Abstract
PURPOSE: Treatment with antiplatelet drugs is a key element of secondary stroke prevention. We investigated long-term antiplatelet drug use in stroke patients with a focus on non-persistence.
METHODS: Population-based prescription register data were used to determine antiplatelet drug use in a cohort of stroke patients discharged from a Danish neurology department. The antiplatelet drugs comprised acetylsalicylic acid (ASA), clopidogrel and dipyridamole (if combined with ASA use). Non-persistence was defined as failure to present a prescription for antiplatelet drugs within 180�days after the dosage of a previous prescription had run out, or within 180�days after discharge. Cox regression was used to identify risk factors for non-persistence.
RESULTS: The cohort comprised 503 patients with ischaemic stroke discharged in 1999-2001. During follow-up (median 2.8�years, interquartile range 0.8-7.8�years), 486 of the subjects presented prescriptions for antiplatelets. Most subjects used a dual regimen of ASA and dipyridamole (N?=?320). Of 110 non-persistent subjects in this group, 64 stopped using ASA, but continued to use dipyridamole in monotherapy. Overall, 181 patients (36�%) were non-persistent. Stroke severity was inversely associated with the risk of non-persistence [NIHSS score on admission 0-3 (reference); 4-6: hazard risk (HR) 0.87, 95 % confidence interval (CI) 0.61-1.25; 7+: HR 0.47, 95 % CI 0.29-0.74].
CONCLUSIONS: Long-term non-persistence with antiplatelet treatment was high and more pronounced in our patients with less severe stroke. Our findings on the use of ASA and dipyridamole indicate that non-persistence may in part be amenable to simple intervention measures.
PMID: 22576729 [PubMed - indexed for MEDLINE]
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Developmental Biology: miRs and Steroids and Growth Control.
Curr Biol. 2013 Apr 22;23(8):R328-30
Authors: Delanoue R, L�opold P
Abstract
The Drosophila miRNA-encoding gene bantam controls cell and tissue growth. A new study now reveals that a large part of its effects on growth could come from its inhibition of the production of the molting hormone ecdysone.
PMID: 23618672 [PubMed - in process]
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Image-based high-throughput screening for inhibitors of angiogenesis.
Methods Mol Biol. 2013;931:139-51
Authors: Evensen L, Link W, Lorens JB
Abstract
Automated multicolor fluorescence microscopy facilitates high-throughput quantitation of cellular parameters of complex, organotypic systems. In vitro co-cultured vascular cells form capillary-like networks that model facets of angiogenesis, making it an attractive alternative for anti-angiogenic drug discovery. We have adapted this angiogenesis assay system to a high-throughput format to enable automated image-based high-throughput screening of live primary human vascular cell co-cultures with chemical libraries for anti-angiogenic drug discovery. Protocols are described for setup of a fluorescence-based co-culture assay, live cell image acquisition, image analysis of morphological parameters, and screening data handling.
PMID: 23027002 [PubMed - indexed for MEDLINE]
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Targeted therapies and the treatment of non-clear cell renal cell carcinoma.
Ann Oncol. 2013 Apr 26;
Authors: Bellmunt J, Dutcher J
Abstract
BACKGROUND: Targeted therapies have shown profound effects on the outcome of patients with advanced renal cell carcinoma (RCC). However, the optimal treatment for RCC of non-clear cell histology (nccRCC)-typically excluded from trials of targeted agents-remains uncertain. MATERIALS AND METHODS: By carrying out extensive searches of PubMed and ASCO databases, we identified and summarised research into the biological characteristics, clinical behaviour and treatment of different histological subtypes of nccRCC, focusing on targeted therapy. RESULTS: The available data suggest that treatments currently approved for RCC are active in ncc subtypes, although the overall clinical benefit may be less than for clear cell RCC. Temsirolimus has proven benefit over interferon-alfa (IFN-?) in patients with nccRCC, based on phase III data, while everolimus, sunitinib and sorafenib have all demonstrated some degree of activity in nccRCC in expanded-access trials. No clear picture has emerged of whether individual histological subtypes are particularly responsive to any individual treatment. CONCLUSIONS: Further molecular studies into the pathogenesis of RCC histological subtypes will help direct the development of novel, appropriate targeted agents. Clinical trials specifically designed to evaluate the role of targeted agents in nccRCC are ongoing, and data from trials with sunitinib and everolimus will be reported soon.
PMID: 23625974 [PubMed - as supplied by publisher]
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Genetic Deletion of Microsomal Prostaglandin E Synthase-1 Suppresses Mouse Mammary Tumor Growth and Angiogenesis.
Prostaglandins Other Lipid Mediat. 2013 Apr 25;
Authors: Howe LR, Subbaramaiah K, Kent CV, Zhou XK, Chang SH, Hla T, Jakobsson PJ, Hudis CA, Dannenberg AJ
Abstract
The cyclooxygenase/prostaglandin (COX/PG) signaling pathway is of central importance in inflammation and neoplasia. COX inhibitors are widely used for analgesia and also have demonstrated activity for cancer prophylaxis. However, cardiovascular toxicity associated with this drug class diminishes their clinical utility and motivates the development of safer approaches both for pain relief and cancer prevention. The terminal synthase microsomal PGE synthase-1 (mPGES-1) has attracted considerable attention as a potential target. Overexpression of mPGES-1 has been observed in both colorectal and breast cancers, and gene knockout and overexpression approaches have established a role for mPGES-1 in gastrointestinal carcinogenesis. Here we evaluate the contribution of mPGES-1 to mammary tumorigenesis using a gene knockout approach. Mice deficient in mPGES-1 were crossed with a strain in which breast cancer is driven by overexpression of human epidermal growth factor receptor 2 (HER2/neu). Loss of mPGES-1 was associated with a substantial reduction in intramammary PGE2 levels, aromatase activity, and angiogenesis in mammary glands from HER2/neu transgenic mice. Consistent with these findings, we observed a significant reduction in multiplicity of tumors ? 1mm in diameter, suggesting that mPGES-1 contributes to mammary tumor growth. Our data identify mPGES-1 as a potential anti-breast cancer target.
PMID: 23624019 [PubMed - as supplied by publisher]
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Trends in all-cause mortality among patients with chronic myeloid leukemia: A Surveillance, Epidemiology, and End Results database analysis.
Cancer. 2013 Apr 26;
Authors: Brunner AM, Campigotto F, Sadrzadeh H, Drapkin BJ, Chen YB, Neuberg DS, Fathi AT
Abstract
BACKGROUND: Outcomes for patients with chronic myeloid leukemia (CML) have improved after the advent of tyrosine kinase inhibitors (TKIs), which target the BCR/ABL fusion gene product. Nonetheless, differences in survival persist between age groups. The authors performed a retrospective cohort study using the Surveillance, Epidemiology, and End Results (SEER) database to assess 5-year overall survival (OS) in various patient age groups. METHODS: Patients who had a diagnosis of CML were identified using the SEER 19 registries database. Patients who were included had SEER diagnosis codes for CML not otherwise specified (code 9863) and BCR/ABL-positive CML (code 9875) diagnosed between January 2000 and December 2005. Patients were divided into cohorts based on age at diagnosis: ages 15 to 44 years, 45 to 64 years, 65 to 74 years, and 75 to 84 years. OS was estimated using the Kaplan-Meier method, and Cox regression was used to estimate predictors of patient survival. RESULTS: In total, 5138 patients with a new CML diagnosis were identified. Five-year OS improved for all patients between the years 2000 and 2005. Compared with patients who were diagnosed in 2000, 5-year survival improved among patients ages 15 to 44 years (hazard ratio [HR] for mortality, 0.424; P?<?.0001), ages 45 to 64 years (HR, 0.716; P?=?.0315), and ages 65 to 74 years (HR, 0.692; P?=?.0126); and patients ages 75 to 84 years had an increased 5-year OS rate from 19.2% in 2000 to 36.4% in 2005 (HR, 0.568; P?<?.0001). CONCLUSIONS: OS at 5 years improved among all patients, including those ages 75 to 84 years, a group with historically poor outcomes. However, older age retained an association with worse survival, suggesting opportunities for further progress. Cancer 2013;. � 2013 American Cancer Society.
PMID: 23625575 [PubMed - as supplied by publisher]
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Clinical everolimus experience in pediatric renal transplant patients.
Transplant Proc. 2013 Apr;45(3):913-6
Authors: Dincel N, Bulut IK, Sezer T�, Mir S, Ho?co?kun C
Abstract
OBJECTIVE: Everolimus is a potent immunosuppressive agent that has antiproliferative activities. This study sought to share our experience among renal transplanted children who required conversion from calcineurin inhibitors (CNIs) to the mammalian target of rapamycin inhibitor everolimus.
PATIENTS AND METHODS: Exclusion criteria were multiple organ transplantations, loss of a previous graft due to immunologic reasons, receipt of an organ donated after cardiac death, donor age <5 years or >65 years, panel reactive antibodies >25%, platelets <75,000/mm(3), absolute neutrophil count of <1,500/mm(3), leucocytes <2,500/mm(3), hemoglobin <6 g/dL, severe liver disease, cold ischemia time >40 hours or anti-HLA panel-reactive antibodies >50%.
RESULTS: Eighteen renal transplant patients (10 male, 8 female) underwent conversion to everolimus from CNI: 8 from cyclosporine (CsA) and 10 from tacrolimus. The mean age was 12.6 � 0.9 years and the mean body mass index 21.8 � 1.7 kg/m(2). The mean 2-hour postdose level of CsA before conversion was 671 � 142 ng/mL; the patients on tacrolimus showed a mean trough concentration of 4.5 ng/mL. Six (33,3%) were taking mycophenolate mofetil and 12 (66.6%) enteric-coated mycophenolate sodium. No significant changes were observed in either hepatic functions, serum lipids, or hemograms. There was no mortality or graft loss. The mean level of serum creatinine was 1.3 � 0.7 mg/dL before and 1.09 � 0.6 mg/dL after conversion. Proteinuria observed in only 1 patient was well controlled with angiotensin-converting enzyme inhibitor therapy. All patients responded to statin therapy. One patient developed unilateral lower extremity edema and 1 a lymphocele. Although there were 3 cases (14%) of biopsy-confirmed acute rejection, there was no mortality or graft loss.
CONCLUSIONS: Everolimus conversion has become an excellent choice, offering safety and efficacy with good outcomes.
PMID: 23622585 [PubMed - in process]
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Aromatase inhibition 2013: clinical state of the art and questions that remain to be solved.
Endocr Relat Cancer. 2013 Apr 26;
Authors: Lonning P, Eikesdal HP
Abstract
Following their successfull implementation for the treatment of metastatic breast cancer, the 'third-generation' aromatase inhibitors (anastrozole, letrozole and exemestane) now has become standard adjuvant endocrine treatment for postmenopausal estrogen receptor positive breast cancers. These drugs are all characterized by potent aromatase inhibition, causing >98% inhibition of estrogen synthesis in vivo. A recent meta-analysis found no difference in anti-tumour efficacy between these three compounds. As of today, aromatase inhibitor monotherapy or sequential treatment using tamoxifen followed by an aromatase inhibitor for a total of 5 years are considered equipotent treatment options. Yet currently trials are addressing the potential benefit of extending treatment duration beyond 5 years. Regarding side effects, aromatase inhibitors are not found associated with enhanced risk of cardiovascular disease, and enhanced bone loss is prevented by adding bisphosphonates in concert for those at danger of developing osteoporosis. However, arthralgia and carpal tunnel syndrome preclude drug administration among a few patients. While recent findings have questioned the use of aromatase inhibitors among overweigth and, in particular, obese patients, this problem seems to focus on premenopausal patients treated with an aromatase inhibitor and an LH-RH analogue in concert, questioning the efficacy of LH-RH analogues rather than aromatase inhibitors among overweigth patients. Finally, recent findings revealing a benefit from adding the mTOR inhibitor everolimus to treatment endocrine treatment indicates targeted therapy against defined growth factor pathways to be a way forward reversing acquired resistance to endocrine therapy.
PMID: 23625614 [PubMed - as supplied by publisher]
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Impact of the integrin signaling adaptor protein NEDD9 on prognosis and metastatic behavior of human lung cancer.
Clin Cancer Res. 2012 Nov 15;18(22):6326-38
Authors: Kondo S, Iwata S, Yamada T, Inoue Y, Ichihara H, Kichikawa Y, Katayose T, Souta-Kuribara A, Yamazaki H, Hosono O, Kawasaki H, Tanaka H, Hayashi Y, Sakamoto M, Kamiya K, Dang NH, Morimoto C
Abstract
PURPOSE: In a substantial population of non-small cell lung cancer (NSCLC), expression and activation of EGF receptor (EGFR) have been reported and is regarded as a novel molecular target. A growing body of evidence has shown the signaling crosstalk between EGFR and integrins in cellular migration and invasion. NEDD9 is an integrin signaling adaptor protein composed of multiple domains serving as substrate for a variety of tyrosine kinases. In the present study, we aimed at elucidating a role of NEDD9 in the signaling crosstalk between EGFR and integrins.
EXPERIMENTAL DESIGN: Using NSCLC cell lines, we conducted immunoblotting and cellular migration/invasion assay in vitro. Next, we analyzed metastasis assays in vivo by the use of xenograft transplantation model. Finally, we retrospectively evaluated clinical samples and records of patients with NSCLCs.
RESULTS: We showed that tyrosine phosphorylation of NEDD9 was reduced by the inhibition of EGFR in NSCLC cell lines. Overexpression of constitutively active EGFR caused tyrosine phosphorylation of NEDD9 in the absence of integrin stimulation. By gene transfer and gene knockdown, we showed that NEDD9 plays a pivotal role in cell migration and invasion of those cells in vitro. Furthermore, overexpression of NEDD9 promoted lung metastasis of an NSCLC cell line in NOD/Shi-scid, IL-2R?(null) mice (NOG) mice. Finally, univariate and multivariate Cox model analysis of NSCLC clinical specimens revealed a strong correlation between NEDD9 expression and recurrence-free survival as well as overall survival.
CONCLUSION: Our data thus suggest that NEDD9 is a promising biomarker for the prognosis of NSCLCs and its expression can promote NSCLC metastasis.
PMID: 23037767 [PubMed - indexed for MEDLINE]
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Synthesis and biological evaluation of new benzo-thieno[3,2-d]pyrimidin-4-one sulphonamide thio-derivatives as potential selective cyclooxygenase-2 inhibitors.
Mol Divers. 2013 Apr 26;
Authors: Barone M, Graziano AC, Marrazzo A, Gemmellaro P, Santagati A, Cardile V
Abstract
The aim of this work was to evaluate the potential anti-inflammatory activity of eleven (5-15) new synthesized derivatives of benzo-thieno[3,2-d]pyrimidine on two cell models, namely human keratinocytes NCTC 2544 and mouse monocyte-macrophages J774. For the synthesis of test compounds an efficient approach was developed: the key isothiocyanate was prepared through a simple and ecological method using di-2-pyridyl thionocarbonate (DPT) in substitution of thiophosgene, a highly toxic agent, and the cyclization reaction of benzo-thiosemicarbazide derivates was performed through Wamhoff methods. This procedure can be a new alternative method economically and environmentally advantageous by the simplicity of procedure, reduction of isolation and purification steps, time, costs, and waste production. The potential anti-inflammatory activity of 5-15 was evaluated by determining the expression of cyclooxygenase (COX)-2, inducible NO synthase (iNOS), and intercellular adhesion molecule-1 (ICAM-1), and the release of prostaglandins (PG)E[Formula: see text] and interleukin-8 (IL-8). Our results demonstrate that the compounds 7, 10, 12, 13, 14, and 15 act as a potent inhibitor of COX-2, iNOS, ICAM-1 expression while also suppressing the production of PGE[Formula: see text] and IL-8 in human keratinocytes NCTC 2544 exposed to interferon-gamma (IFN-[Formula: see text]) and histamine and monocyte-macrophages J774 cells treated with lipopolysaccharides (LPS). In conclusion, some derivatives of benzo-thieno[3,2-d]pyrimidine could be developed as a novel class of anti-inflammatory agents.
PMID: 23620375 [PubMed - as supplied by publisher]
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Clustered DNA damage induces pan-nuclear H2AX phosphorylation mediated by ATM and DNA-PK.
Nucleic Acids Res. 2013 Apr 24;
Authors: Meyer B, Voss KO, Tobias F, Jakob B, Durante M, Taucher-Scholz G
Abstract
DNA double-strand breaks (DSB) are considered as the most deleterious DNA lesions, and their repair is further complicated by increasing damage complexity. However, the molecular effects of clustered lesions are yet not fully understood. As the locally restricted phosphorylation of H2AX to form ?H2AX is a key step in facilitating efficient DSB repair, we investigated this process after localized induction of clustered damage by ionizing radiation. We show that in addition to foci at damaged sites, H2AX is also phosphorylated in undamaged chromatin over the whole-cell nucleus in human and rodent cells, but this is not related to apoptosis. This pan-nuclear ?H2AX is mediated by the kinases ataxia telangiectasia mutated and DNA-dependent protein kinase (DNA-PK) that also phosphorylate H2AX at DSBs. The pan-nuclear response is dependent on the amount of DNA damage and is transient even under conditions of impaired DSB repair. Using fluorescence recovery after photobleaching (FRAP), we found that MDC1, but not 53BP1, binds to the nuclear-wide ?H2AX. Consequently, the accumulation of MDC1 at DSBs is reduced. Altogether, we show that a transient dose-dependent activation of the kinases occurring on complex DNA lesions leads to their nuclear-wide distribution and H2AX phosphorylation, yet without eliciting a full pan-nuclear DNA damage response.
PMID: 23620287 [PubMed - as supplied by publisher]
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Combined Treatment With PPAR-? Agonists In Pancreatic Cancer: A Glimmer Of Hope For Cancer Therapy?
Curr Cancer Drug Targets. 2013 Mar 25;
Authors: Dicitore A, Caraglia M, Colao A, Zappavigna S, Mari D, Hofland LJ, Persani L, Vitale G
Abstract
Pancreatic cancer is the fourth leading cause of cancer death, associated to both limited success in treatment and a poor prognosis. The wide number of signalling pathway aberrations contributing to the tumorigenesis, progression and drug resistance, is the main reason for treatments being unsuccessful to date in pancreatic cancer. An additional and still under-investigated intracellular cancer target is the peroxisome proliferator activated receptor gamma (PPAR-?). Notwithstanding, several studies have shown the in vitro antitumor activity of PPAR-? agonists in cancer cells, such agents, if used in monotherapy, were poorly effective in cancer treatment. The present review will focus on the potential therapeutic role of PPAR-? agonists in combination with other drugs (type I interferons, gemcitabine and COX-2 inhibitors), highlighting molecular interactions and signalling pathways involved in pancreatic cancer cells. Understanding of the underlying molecular mechanisms and survival pathways activated in cancer cells should promote the development of new targeted and more successful therapies in the future.
PMID: 23617255 [PubMed - as supplied by publisher]
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Sorafenib and Everolimus in Advanced Clear Cell Renal Carcinoma: A Phase I/II Trial of the SCRI Oncology Research Consortium.
Cancer Invest. 2013 Apr 24;
Authors: Hainsworth JD, Waterhouse DM, Penley WC, Shipley DL, Thompson DS, Webb CD, Anthony Greco F
Abstract
Purpose: To evaluate the feasibility and efficacy of sorafenib and everolimus in renal cell carcinoma (RCC). Methods: Patients with advanced RCC and ?1 previous targeted therapy were treated. Results: Maximum tolerated doses were sorafenib 200�mg PO BID, everolimus 35�mg PO once weekly. Dose-limiting toxicity was hand-foot syndrome. The response rate was 13%; median PFS was 5.45 months (95% CI: 3.8-7.6). Skin toxicity, fatigue, hypertension, proteinuria, and mucositis (usually Grade 2) were common. Conclusions: Fifty percent doses of sorafenib and everolimus were required when these drugs were combined. No increase in efficacy was suggested; toxicity was modestly increased.
PMID: 23614653 [PubMed - as supplied by publisher]
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Clustered DNA damage induces pan-nuclear H2AX phosphorylation mediated by ATM and DNA-PK.
Nucleic Acids Res. 2013 Apr 24;
Authors: Meyer B, Voss KO, Tobias F, Jakob B, Durante M, Taucher-Scholz G
Abstract
DNA double-strand breaks (DSB) are considered as the most deleterious DNA lesions, and their repair is further complicated by increasing damage complexity. However, the molecular effects of clustered lesions are yet not fully understood. As the locally restricted phosphorylation of H2AX to form ?H2AX is a key step in facilitating efficient DSB repair, we investigated this process after localized induction of clustered damage by ionizing radiation. We show that in addition to foci at damaged sites, H2AX is also phosphorylated in undamaged chromatin over the whole-cell nucleus in human and rodent cells, but this is not related to apoptosis. This pan-nuclear ?H2AX is mediated by the kinases ataxia telangiectasia mutated and DNA-dependent protein kinase (DNA-PK) that also phosphorylate H2AX at DSBs. The pan-nuclear response is dependent on the amount of DNA damage and is transient even under conditions of impaired DSB repair. Using fluorescence recovery after photobleaching (FRAP), we found that MDC1, but not 53BP1, binds to the nuclear-wide ?H2AX. Consequently, the accumulation of MDC1 at DSBs is reduced. Altogether, we show that a transient dose-dependent activation of the kinases occurring on complex DNA lesions leads to their nuclear-wide distribution and H2AX phosphorylation, yet without eliciting a full pan-nuclear DNA damage response.
PMID: 23620287 [PubMed - as supplied by publisher]
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Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.
Transfusion. 2012 Nov;52(11):2406-13
Authors: Avanzi MP, Chen A, He W, Mitchell WB
Abstract
BACKGROUND: Large-scale in vitro production of platelets (PLTs) from cord blood stem cells is one goal of stem cell research. One step toward this goal will be to produce polyploid megakaryocytes capable of releasing high numbers of PLTs. Megakaryocyte polyploidization requires distinct cytoskeletal and cellular mechanisms, including actin polymerization, myosin activation, microtubule formation, and increased DNA production. In this study we variably combined inhibition of these principal mechanisms of cytokinesis with the goal of driving polyploidization in megakaryocytes.
STUDY DESIGN AND METHODS: Megakaryocytes were derived from umbilical cord blood and cultured with reagents that inhibit distinct mechanisms of cytokinesis: Rho-Rock inhibitor (RRI), Src inhibitor (SI), nicotinamide (NIC), aurora B inhibitor (ABI), and myosin light chain kinase inhibitor (MLCKI). Combinations of reagents were used to determine their interactions and to maximize megakaryocyte ploidy.
RESULTS: Treatment with RRI, NIC, SI, and ABI, but not with MLCKI, increased the final ploidy and RRI was the most effective single reagent. RRI and MLCKI, both inhibitors of MLC activation, resulted in opposite ploidy outcomes. Combinations of reagents also increased ploidy and the use of NIC, SI, and ABI was as effective as RRI alone. Addition of MLCKI to NIC, SI, and ABI reached the highest level of polyploidization.
CONCLUSION: Megakaryocyte polyploidization results from modulation of a combination of distinct cytokinesis pathways. Reagents targeting distinct cytoskeletal pathways produced additive effects in final megakaryocyte ploidy. The RRI, however, showed no additive effect but produced a high final ploidy due to overlapping inhibition of multiple cytokinesis pathways.
PMID: 22612069 [PubMed - indexed for MEDLINE]
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Image-based high-throughput screening for inhibitors of angiogenesis.
Methods Mol Biol. 2013;931:139-51
Authors: Evensen L, Link W, Lorens JB
Abstract
Automated multicolor fluorescence microscopy facilitates high-throughput quantitation of cellular parameters of complex, organotypic systems. In vitro co-cultured vascular cells form capillary-like networks that model facets of angiogenesis, making it an attractive alternative for anti-angiogenic drug discovery. We have adapted this angiogenesis assay system to a high-throughput format to enable automated image-based high-throughput screening of live primary human vascular cell co-cultures with chemical libraries for anti-angiogenic drug discovery. Protocols are described for setup of a fluorescence-based co-culture assay, live cell image acquisition, image analysis of morphological parameters, and screening data handling.
PMID: 23027002 [PubMed - indexed for MEDLINE]
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Potential Role of mTORC2 as a Therapeutic Target in Clear Cell Carcinoma of the Ovary.
Mol Cancer Ther. 2013 Apr 24;
Authors: Hisamatsu T, Mabuchi S, Matsumoto Y, Kawano M, Sasano T, Takahashi R, Sawada K, Ito K, Kurachi H, Schilder RJ, Testa JR, Kimura T
Abstract
The goal of this study was to examine the role of mTORC2 as a therapeutic target in ovarian clear cell carcinoma (CCC), which is regarded as an aggressive, chemoresistant histological subtype. Using tissue microarrays of 98 primary ovarian cancers (52 CCCs and 46 serous adenocarcinomas (SACs)), activation of mTORC2 was assessed by immunohistochemistry. Then, the growth-inhibitory effect of mTORC2-targeting therapy, as well as the role of mTORC2 signaling as a mechanism for acquired resistance to the mTORC1 inhibitor RAD001 in ovarian CCC, were examined using two pairs of RAD001-sensitive parental (RMG2 and HAC2) and RAD001-resistant CCC cell lines (RMG2-RR and HAC2-RR). mTORC2 was more frequently activated in CCCs than in SACs (71.2% vs. 45.7%). Simultaneous inhibition of mTORC1 and mTORC2 by AZD8055 markedly inhibited the proliferation of both RAD001-sensitive and RAD001-resistant cells in vitro. Treatment with RAD001 induced mTORC2-mediated AKT activation in RAD001-sensitive CCC cells. Moreover, increased activation of mTORC2-AKT signaling was observed in RAD001-resistant CCC cells compared to the respective parental cells. Inhibition of mTORC2 during RAD001 treatment enhanced the anti-tumor effect of RAD001 and prevented CCC cells from acquiring resistance to RAD001. In conclusion, mTORC2 is frequently activated, and can be a promising therapeutic target, in ovarian CCCs. Moreover, mTORC2-targeted therapy may be efficacious in a front-line setting as well as for second-line treatment of recurrent disease developing after RAD001-treatment.
PMID: 23615631 [PubMed - as supplied by publisher]
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Potential Role of mTORC2 as a Therapeutic Target in Clear Cell Carcinoma of the Ovary.
Mol Cancer Ther. 2013 Apr 24;
Authors: Hisamatsu T, Mabuchi S, Matsumoto Y, Kawano M, Sasano T, Takahashi R, Sawada K, Ito K, Kurachi H, Schilder RJ, Testa JR, Kimura T
Abstract
The goal of this study was to examine the role of mTORC2 as a therapeutic target in ovarian clear cell carcinoma (CCC), which is regarded as an aggressive, chemoresistant histological subtype. Using tissue microarrays of 98 primary ovarian cancers (52 CCCs and 46 serous adenocarcinomas (SACs)), activation of mTORC2 was assessed by immunohistochemistry. Then, the growth-inhibitory effect of mTORC2-targeting therapy, as well as the role of mTORC2 signaling as a mechanism for acquired resistance to the mTORC1 inhibitor RAD001 in ovarian CCC, were examined using two pairs of RAD001-sensitive parental (RMG2 and HAC2) and RAD001-resistant CCC cell lines (RMG2-RR and HAC2-RR). mTORC2 was more frequently activated in CCCs than in SACs (71.2% vs. 45.7%). Simultaneous inhibition of mTORC1 and mTORC2 by AZD8055 markedly inhibited the proliferation of both RAD001-sensitive and RAD001-resistant cells in vitro. Treatment with RAD001 induced mTORC2-mediated AKT activation in RAD001-sensitive CCC cells. Moreover, increased activation of mTORC2-AKT signaling was observed in RAD001-resistant CCC cells compared to the respective parental cells. Inhibition of mTORC2 during RAD001 treatment enhanced the anti-tumor effect of RAD001 and prevented CCC cells from acquiring resistance to RAD001. In conclusion, mTORC2 is frequently activated, and can be a promising therapeutic target, in ovarian CCCs. Moreover, mTORC2-targeted therapy may be efficacious in a front-line setting as well as for second-line treatment of recurrent disease developing after RAD001-treatment.
PMID: 23615631 [PubMed - as supplied by publisher]
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