Image-based high-throughput screening for inhibitors of angiogenesis.

Related Articles

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]

coxinhibitors c-met inhibitors zm-447439

Risk evaluation and mitigation strategies: a focus on the mammalian target of rapamycin inhibitors.

Risk evaluation and mitigation strategies: a focus on the mammalian target of rapamycin inhibitors.

Prog Transplant. 2013 Mar;23(1):55-7

Authors: Gabardi S

Abstract
Objective-To review the history of risk evaluation and mitigation strategies (REMS) with the mammalian target of rapamycin (mToR) inhibitors, evaluate their required REMS elements, and delineate the reasons for them being released from their REMS requirements.Data Sources and Extraction-Articles were identified through a literature search of MEDLINE and EMBASE (January 2007-July 2012) using the search terms: risk evaluation and mitigation strategies, REMS, everolimus, sirolimus and organ transplant (individual organs also were searched). Information from the Federal Register, the Food and Drug Administration, and the manufacturers of the mToR inhibitors was also evaluated.Data Synthesis-REMS are strategies implemented to manage known or potential risks associated with medications and to ensure ongoing pharmacovigilance throughout the life of a pharmaceutical product. The mToR inhibitors have been associated with several potential risks, including proteinuria, graft thrombosis, and wound-healing complications. The Food and Drug Administration approved REMS programs for both sirolimus and everolimus. The manufacturers of both medications complied with the components of their approved REMS, but after less than 2 years, both medications have been relieved of their REMS obligations.Conclusion-The only element of the sirolimus REMS was a medication guide, whereas the everolimus REMS consisted of a medication guide and a communication plan. The sirolimus REMS was implemented more than 10 years after its initial approval by the Food and Drug Administration, but was released from its REMS requirement within 7 months of its implementation. The everolimus REMS was instituted upon initial approval and was removed approximately 2 years later. Both medications' REMS were always intended to educate health care providers and patients about the potential risks associated with this transplant immunosuppressant. Transplant practitioners should be familiar with the mToR inhibitors' associated risks and properly educate patients regarding the inhibitors' risk-benefit profiles.

PMID: 23448821 [PubMed - in process]

zm-447439 rad001 ecdysone

A novel role of Kr�ppel-like factor 8 in DNA repair in breast cancer cells.

Related Articles

A novel role of Kr�ppel-like factor 8 in DNA repair in breast cancer cells.

J Biol Chem. 2012 Dec 21;287(52):43720-9

Authors: Lu H, Hu L, Li T, Lahiri S, Shen C, Wason MS, Mukherjee D, Xie H, Yu L, Zhao J

Abstract
Kr�ppel-like factor 8 (KLF8) regulates critical gene transcription and cellular events associated with cancer. However, the role of KLF8 in cancer remains largely unknown. Here, we report a surprisingly novel role for KLF8 in DNA repair in breast cancer cells. Comet, clonogenic, and WST-1 assays showed that KLF8 expression is required for protecting human breast cancer cells from doxorubicin-induced DNA damage and cell death. Western blotting indicated that overexpression of ectopic KLF8 attenuated the levels of the DNA damage marker ?H2A.X in doxorubicin-treated PARP-1(+/+) but not PARP-1(-/-) mouse embryonic fibroblasts, whereas the PARP-1-binding-defective KLF8 mutant failed to do so. Interestingly, in response to the DNA damage, KLF8 was phosphorylated by the DNA-dependent protein kinase catalytic subunit and, subsequently, SUMOylated by SUMO E3 ligases protein inhibitors of activated STAT (PIASs), which depends upon the interaction of KLF8 with DNA-dependent protein kinase catalytic subunit, PIASs, and PARP-1 as well as their enzymatic activities. Lastly, we show evidence that KLF8 was recruited to the DNA damage site. These results suggest a novel role and mechanism for KLF8 in the regulation of DNA repair and therapeutic resistance in breast cancer cells.

PMID: 23105099 [PubMed - indexed for MEDLINE]

coxinhibitors c-met inhibitors zm-447439

Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.

Related Articles

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]

c-met inhibitors zm-447439 rad001

Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.

Related Articles

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]

rad001 ecdysone chir-258

?-Catenin-driven cancers require a YAP1 transcriptional complex for survival and tumorigenesis.

Related Articles

?-Catenin-driven cancers require a YAP1 transcriptional complex for survival and tumorigenesis.

Cell. 2012 Dec 21;151(7):1457-73

Authors: Rosenbluh J, Nijhawan D, Cox AG, Li X, Neal JT, Schafer EJ, Zack TI, Wang X, Tsherniak A, Schinzel AC, Shao DD, Schumacher SE, Weir BA, Vazquez F, Cowley GS, Root DE, Mesirov JP, Beroukhim R, Kuo CJ, Goessling W, Hahn WC

Abstract
Wnt/?-catenin signaling plays a key role in the pathogenesis of colon and other cancers; emerging evidence indicates that oncogenic ?-catenin regulates several biological processes essential for cancer initiation and progression. To decipher the role of ?-catenin in transformation, we classified ?-catenin activity in 85 cancer cell lines in which we performed genome-scale loss-of-function screens and found that ?-catenin active cancers are dependent on a signaling pathway involving the transcriptional regulator YAP1. Specifically, we found that YAP1 and the transcription factor TBX5 form�a complex with ?-catenin. Phosphorylation of YAP1 by the tyrosine kinase YES1 leads to localization of this complex to the promoters of antiapoptotic genes, including BCL2L1 and BIRC5. A small-molecule inhibitor of YES1 impeded the proliferation of ?-catenin-dependent cancers in both cell lines and animal models. These observations define a ?-catenin-YAP1-TBX5 complex essential to the transformation and survival of ?-catenin-driven cancers.

PMID: 23245941 [PubMed - indexed for MEDLINE]

dna-pk coxinhibitors c-met inhibitors

Risk of significant infection in rheumatoid arthritis patients switching anti-tumor necrosis factor-? drugs.

Related Articles

Risk of significant infection in rheumatoid arthritis patients switching anti-tumor necrosis factor-? drugs.

Semin Arthritis Rheum. 2012 Oct;42(2):119-26

Authors: Nguyen-Khoa BA, Goehring EL, Alexander KA, Dong W, Napalkov P, Jones JK

Abstract
OBJECTIVES: To describe rates of first significant infection of rheumatoid arthritis patients who switch between anti-tumor necrosis factor (aTNF) drugs.
METHODS: Subjects with rheumatoid arthritis who received only aTNF drugs were observed in an insurance claims database from January 2001 to December 2007. Nonswitchers (NS) remained on one aTNF throughout the study period (date of the first aTNF claim was the index date); switchers (S) received at least one other aTNF (claim date for the 2nd agent was the index date). Significant infections included those that required intravenous antibiotics or hospitalization. Two attributable risk periods were used: (1) an infection occurring ?90 days following a claim for an aTNF (90-day) and (2) an infection occurring after the index date (ever-treated). Follow-up was censored at the first occurrence of a significant infection event, end of eligibility, or end of study period. Data were analyzed using Cox regression.
RESULTS: In 13,752 NS and 2293 S patients, time-stratified rates declined 2- to 3-fold between the first year versus ?2 years. Risk of significant infection was not different for either attribution model [90-day hazard ratio (HR) = 0.93, 95CI: 0.74 to 1.17, P = 0.55; ever treated HR = 0.94, 95CI: 0.78 to 1.15, P = 0.57]. First and second year rates were similar. Predictors included age ?50 years; history of significant or opportunistic infection, diabetes, respiratory disease; Charlson score ?2; or prior hospitalizations.
CONCLUSIONS: The risk of a significant infection was not different between NS and S patients. Regardless of switching status, the rate of infection was greater in the first year. This study was limited by the lack of clinical data to determine the reason for switching.

PMID: 22595643 [PubMed - indexed for MEDLINE]

zm-447439 rad001 ecdysone

The potential therapeutic benefits of vitamin D in the treatment of estrogen receptor positive breast cancer.

Related Articles

The potential therapeutic benefits of vitamin D in the treatment of estrogen receptor positive breast cancer.

Steroids. 2012 Sep;77(11):1107-12

Authors: Krishnan AV, Swami S, Feldman D

Abstract
Calcitriol (1,25-dihydroxyvitamin D(3)), the hormonally active form of vitamin D, inhibits the growth of many malignant cells including breast cancer (BCa) cells. The mechanisms of calcitriol anticancer actions include cell cycle arrest, stimulation of apoptosis and inhibition of invasion, metastasis and angiogenesis. In addition we have discovered new pathways of calcitriol action that are especially relevant in inhibiting the growth of estrogen receptor positive (ER+) BCa cells. Calcitriol suppresses COX-2 expression and increases that of 15-PGDH thereby reducing the levels of inflammatory prostaglandins (PGs). Our in vitro and in vivo studies show that calcitriol decreases the expression of aromatase, the enzyme that catalyzes estrogen synthesis selectively in BCa cells and in the mammary adipose tissue surrounding BCa, by a direct repression of aromatase transcription via promoter II as well as an indirect effect due to the reduction in the levels of PGs, which are major stimulator of aromatase transcription through promoter II. Calcitriol down-regulates the expression of ER? and thereby attenuates estrogen signaling in BCa cells including the proliferative stimulus provided by estrogens. Thus the inhibition of estrogen synthesis and signaling by calcitriol and its anti-inflammatory actions will play an important role in inhibiting ER+BCa. We hypothesize that dietary vitamin D would exhibit similar anticancer activity due to the presence of the enzyme 25-hydroxyvitamin D-1?-hydroxylase (CYP27B1) in breast cells ensuring conversion of circulating 25-hydroxyvitamin D to calcitriol locally within the breast micro-environment where it can act in a paracrine manner to inhibit BCa growth. Cell culture and in vivo data in mice strongly suggest that calcitriol and dietary vitamin D would play a beneficial role in the prevention and/or treatment of ER+BCa in women.

PMID: 22801352 [PubMed - indexed for MEDLINE]

dna-pk coxinhibitors c-met inhibitors

Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.

Related Articles

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]

ecdysone chir-258 dovitinib

Regulation of Drosophila metamorphosis by xenobiotic response regulators.

Regulation of Drosophila metamorphosis by xenobiotic response regulators.

PLoS Genet. 2013 Feb;9(2):e1003263

Authors: Deng H, Kerppola TK

Abstract
Mammalian Nrf2-Keap1 and the homologous Drosophila CncC-dKeap1 protein complexes regulate both transcriptional responses to xenobiotic compounds as well as native cellular and developmental processes. The relationships between the functions of these proteins in xenobiotic responses and in development were unknown. We investigated the genes regulated by CncC and dKeap1 during development and the signal transduction pathways that modulate their functions. CncC and dKeap1 were enriched within the nuclei in many tissues, in contrast to the reported cytoplasmic localization of Keap1 and Nrf2 in cultured mammalian cells. CncC and dKeap1 occupied ecdysone-regulated early puffs on polytene chromosomes. Depletion of either CncC or dKeap1 in salivary glands selectively reduced early puff gene transcription. CncC and dKeap1 depletion in the prothoracic gland as well as cncC(K6/K6) and dKeap1(EY5/EY5) loss of function mutations in embryos reduced ecdysone-biosynthetic gene transcription. In contrast, dKeap1 depletion and the dKeap1(EY5/EY5) loss of function mutation enhanced xenobiotic response gene transcription in larvae and embryos, respectively. Depletion of CncC or dKeap1 in the prothoracic gland delayed pupation by decreasing larval ecdysteroid levels. CncC depletion suppressed the premature pupation and developmental arrest caused by constitutive Ras signaling in the prothoracic gland; conversely, constitutive Ras signaling altered the loci occupied by CncC on polytene chromosomes and activated transcription of genes at these loci. The effects of CncC and dKeap1 on both ecdysone-biosynthetic and ecdysone-regulated gene transcription, and the roles of CncC in Ras signaling in the prothoracic gland, establish the functions of these proteins in the neuroendocrine axis that coordinates insect metamorphosis.

PMID: 23408904 [PubMed - in process]

c-met inhibitors zm-447439 rad001

A novel role of Kr�ppel-like factor 8 in DNA repair in breast cancer cells.

Related Articles

A novel role of Kr�ppel-like factor 8 in DNA repair in breast cancer cells.

J Biol Chem. 2012 Dec 21;287(52):43720-9

Authors: Lu H, Hu L, Li T, Lahiri S, Shen C, Wason MS, Mukherjee D, Xie H, Yu L, Zhao J

Abstract
Kr�ppel-like factor 8 (KLF8) regulates critical gene transcription and cellular events associated with cancer. However, the role of KLF8 in cancer remains largely unknown. Here, we report a surprisingly novel role for KLF8 in DNA repair in breast cancer cells. Comet, clonogenic, and WST-1 assays showed that KLF8 expression is required for protecting human breast cancer cells from doxorubicin-induced DNA damage and cell death. Western blotting indicated that overexpression of ectopic KLF8 attenuated the levels of the DNA damage marker ?H2A.X in doxorubicin-treated PARP-1(+/+) but not PARP-1(-/-) mouse embryonic fibroblasts, whereas the PARP-1-binding-defective KLF8 mutant failed to do so. Interestingly, in response to the DNA damage, KLF8 was phosphorylated by the DNA-dependent protein kinase catalytic subunit and, subsequently, SUMOylated by SUMO E3 ligases protein inhibitors of activated STAT (PIASs), which depends upon the interaction of KLF8 with DNA-dependent protein kinase catalytic subunit, PIASs, and PARP-1 as well as their enzymatic activities. Lastly, we show evidence that KLF8 was recruited to the DNA damage site. These results suggest a novel role and mechanism for KLF8 in the regulation of DNA repair and therapeutic resistance in breast cancer cells.

PMID: 23105099 [PubMed - indexed for MEDLINE]

chir-258 dovitinib dna-pk

Met receptor acts uniquely for survival and morphogenesis of EGFR-dependent normal mammary epithelial and cancer cells.

Related Articles

Met receptor acts uniquely for survival and morphogenesis of EGFR-dependent normal mammary epithelial and cancer cells.

PLoS One. 2012;7(9):e44982

Authors: Accornero P, Miretti S, Bersani F, Quaglino E, Martignani E, Baratta M

Abstract
Mammary gland development and breast cancer growth require multiple factors both of endocrine and paracrine origin. We analyzed the roles of Epidermal Growth Factor Receptor (EGFR) and Hepatocyte Growth Factor Receptor (Met) in mammary epithelial cells and mammary tumor cells derived from a mutated-ErbB2 transgenic mice. By using highly specific tyrosine kinase inhibitors we found that MCF-10A and NMuMG mammary epithelial cell lines are totally dependent on EGFR activation for their growth and survival. Proliferation and 3D-morphogenesis assays showed that HGF had no role in maintaining mammary cell viability, but was the only cytokine able to rescue EGFR-inhibited mammary cells. Insulin-Like Growth Factor-I (IGF-I), basic-Fibroblast Growth Factor (b-FGF) and Neuregulin, which are well known mammary morphogenic factors, did not rescue proliferation or morphogenesis in these cell lines, following EGFR inhibition. Similarly, ErbB2-driven tumor cells are EGFR-dependent and also display HGF-mediated rescue. Western-blot analysis of the signaling pathways involved in rescue after EGFR inhibition indicated that concomitant ERK1/2 and AKT activation was exclusively driven by Met, but not by IGF-I or b-FGF. These results describe a unique role for EGFR and Met in mammary epithelial cells by showing that similar pathways can be used by tumorigenic cells to sustain growth and resist to EGFR-directed anti-tumorigenic drugs.

PMID: 23028720 [PubMed - indexed for MEDLINE]

chir-258 dovitinib dna-pk

Everolimus-induced recurrent pericardial effusion after kidney transplantation.

Everolimus-induced recurrent pericardial effusion after kidney transplantation.

Transpl Int. 2013 Feb 27;

Authors: Zeidan S, Ribes D, Cointault O, Gautier M, Marcheix B, Kamar N

PMID: 23441996 [PubMed - as supplied by publisher]

zm-447439 rad001 ecdysone

Image-based high-throughput screening for inhibitors of angiogenesis.

Related Articles

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]

dna-pk coxinhibitors c-met inhibitors

Generation and characterization of severe combined immunodeficiency rats.

Related Articles

Generation and characterization of severe combined immunodeficiency rats.

Cell Rep. 2012 Sep 27;2(3):685-94

Authors: Mashimo T, Takizawa A, Kobayashi J, Kunihiro Y, Yoshimi K, Ishida S, Tanabe K, Yanagi A, Tachibana A, Hirose J, Yomoda J, Morimoto S, Kuramoto T, Voigt B, Watanabe T, Hiai H, Tateno C, Komatsu K, Serikawa T

Abstract
Severe combined immunodeficiency (SCID) mice, the most widely used animal model of DNA-PKcs (Prkdc) deficiency, have contributed enormously to our understanding of immunodeficiency, lymphocyte development, and DNA-repair mechanisms, and they are ideal hosts for allogeneic and xenogeneic tissue transplantation. Here, we use zinc-finger nucleases to generate rats that lack either the Prkdc gene (SCID) or the Prkdc and Il2rg genes (referred to as F344-scid gamma [FSG] rats). SCID rats show several phenotypic differences from SCID mice, including growth retardation, premature senescence, and a more severe immunodeficiency without "leaky" phenotypes. Double-knockout FSG rats show an even more immunocompromised phenotype, such as the abolishment of natural killer cells. Finally, xenotransplantation of human induced pluripotent stem cells, ovarian cancer cells, and hepatocytes shows that SCID and FSG rats can act as hosts for xenogeneic tissue grafts and stem cell transplantation and may be useful for preclinical testing of new drugs.

PMID: 22981234 [PubMed - indexed for MEDLINE]

ecdysone chir-258 dovitinib

Generation and characterization of severe combined immunodeficiency rats.

Related Articles

Generation and characterization of severe combined immunodeficiency rats.

Cell Rep. 2012 Sep 27;2(3):685-94

Authors: Mashimo T, Takizawa A, Kobayashi J, Kunihiro Y, Yoshimi K, Ishida S, Tanabe K, Yanagi A, Tachibana A, Hirose J, Yomoda J, Morimoto S, Kuramoto T, Voigt B, Watanabe T, Hiai H, Tateno C, Komatsu K, Serikawa T

Abstract
Severe combined immunodeficiency (SCID) mice, the most widely used animal model of DNA-PKcs (Prkdc) deficiency, have contributed enormously to our understanding of immunodeficiency, lymphocyte development, and DNA-repair mechanisms, and they are ideal hosts for allogeneic and xenogeneic tissue transplantation. Here, we use zinc-finger nucleases to generate rats that lack either the Prkdc gene (SCID) or the Prkdc and Il2rg genes (referred to as F344-scid gamma [FSG] rats). SCID rats show several phenotypic differences from SCID mice, including growth retardation, premature senescence, and a more severe immunodeficiency without "leaky" phenotypes. Double-knockout FSG rats show an even more immunocompromised phenotype, such as the abolishment of natural killer cells. Finally, xenotransplantation of human induced pluripotent stem cells, ovarian cancer cells, and hepatocytes shows that SCID and FSG rats can act as hosts for xenogeneic tissue grafts and stem cell transplantation and may be useful for preclinical testing of new drugs.

PMID: 22981234 [PubMed - indexed for MEDLINE]

rad001 ecdysone chir-258

Population pharmacokinetic/pharmacodynamic modeling to assist dosing schedule selection for dovitinib.

Related Articles

Population pharmacokinetic/pharmacodynamic modeling to assist dosing schedule selection for dovitinib.

J Clin Pharmacol. 2013 Jan;53(1):14-20

Authors: Wang X, Kay A, Anak O, Angevin E, Escudier B, Zhou W, Feng Y, Dugan M, Schran H

Abstract
Dovitinib is an oral multitargeted kinase inhibitor with potent activity against receptors for vascular endothelial growth factor, platelet-derived growth factor, and basic fibroblast growth factor. Initial phase 1 to 2 studies of dovitinib using a continuous daily dosing schedule has shown that dovitinib exhibits a prolonged and overproportional increase in dose and exposure relationship above 400 mg/d. To address this, intermittent dosing schedules were explored using a model-based approach. A semi-mechanistic population pharmcokinetic/pharmacodynamic (PD) model was developed from 4 dovitinib phase 1 studies with daily dosing schedules. Autoinduction of cytochrome P450 1A (CYP1A) responsible for dovitinib metabolism was described using an indirect response model. Simulation of dovitinib plasma concentration profiles following 4 intermittent dosing schedules suggested that intermittent dosing could prevent prolonged drug accumulation. Based on the simulated plasma profiles, PD response, and patient compliance, a 5-days-on/2-days-off intermittent dosing schedule was selected for a phase 1 to 2 clinical study. The observed dovitinib plasma concentrations in this study confirmed the model predictions. Furthermore, dovitinib was well tolerated, and antitumor activity was observed as well in this new study. The 5-days-on/2-days-off dosing schedule is currently used in a dovitinib registration trial and other clinical trials.

PMID: 23400739 [PubMed - in process]

dna-pk coxinhibitors c-met inhibitors

Metabolomic investigation of the anti-platelet aggregation activity of ginsenoside Rk? reveals attenuated 12-HETE production.

Related Articles

Metabolomic investigation of the anti-platelet aggregation activity of ginsenoside Rk? reveals attenuated 12-HETE production.

J Proteome Res. 2012 Oct 5;11(10):4939-46

Authors: Ju HK, Lee JG, Park MK, Park SJ, Lee CH, Park JH, Kwon SW

Abstract
Comprehensive metabolomics analysis is an effective method of measuring metabolite levels in the body following administration of a pharmaceutical compound and can allow for monitoring of the effects of the compound or assessment of appropriate treatment options for individual patients. In the present metabolomics study, samples pretreated with antiplatelet compounds were extracted and subjected to ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry. The acquired data were processed using peak clustering and evaluated by partial least-squares (PLS) and orthogonal projections to latent structures discriminant analyses (OPLS-DA). As a result, meaningful endogenous metabolites, namely eicosanoids and thromboxane B(2) (TXB(2)), were identified. TXB(2), a key element in platelet aggregation, was decreased upon ginsenoside Rk(1) treatment via inhibition of cyclooxygenase (COX) activity. One of the arachidonic acid (AA) metabolites, 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE), was decreased significantly in the ginsenoside Rk(1)-treated platelets compared to the AA-induced group. In the mechanism study of ginsenoside Rk(1), a strong linkage to intracellular calcium levels, which induce platelet activation, was found. Additionally, the translocation of 12-LOX from cytosol to membrane, which is related with the intracellular calcium levels, was determined. Therefore, a decreased 12-HETE level induced by ginsenoside Rk(1) on antiplatelet aggregation is related to 12-LOX translocation resulting from decreased Ca(2+) levels. This study shows that global metabolomic analysis has potential for use in understanding the biological behavior of antiplatelet drugs.

PMID: 22873173 [PubMed - indexed for MEDLINE]

dovitinib dna-pk coxinhibitors

Everolimus in Advanced Pancreatic Neuroendocrine Tumors: The Clinical Experience.

Everolimus in Advanced Pancreatic Neuroendocrine Tumors: The Clinical Experience.

Cancer Res. 2013 Feb 22;

Authors: Yao JC, Phan AT, Jehl V, Shah G, Meric-Bernstam F

Abstract
The incidence of neuroendocrine tumors (NET) has increased dramatically in the past 30 years. This information has revitalized basic and clinical research into the molecular biology of NET and has resulted in the recent approval of new therapies for pancreatic NET (pNET), including the oral inhibitor of the mTOR everolimus. Everolimus significantly improved progression-free survival among patients with pNET in the phase III RADIANT-3 study. Here, we review the clinical studies showing the efficacy of everolimus in pNET and summarize the translational science from these studies. To understand the mechanisms of resistance and cause of treatment failure, we compared the type of progression events observed in the everolimus and placebo arms of the RADIANT-3 study. Comparison of the everolimus arm to the placebo arm indicated the fractions of progression events due to new metastasis only (21% vs. 22%), growth of preexisting lesions only (54% vs. 49%), and new metastasis along with growth of preexisting lesions (24% vs. 27%) were similar. These results suggest that although everolimus delays disease progression in patients with pNET, patients who experience disease progression while on everolimus do not appear to have a more aggressive metastatic phenotype than those whose disease progresses while on placebo. Cancer Res; 73(5); 1-5. �2013 AACR.

PMID: 23436795 [PubMed - as supplied by publisher]

zm-447439 rad001 ecdysone

Chemotherapy alters monocyte differentiation to favor generation of cancer-supporting M2 macrophages in the tumor microenvironment.

Chemotherapy alters monocyte differentiation to favor generation of cancer-supporting M2 macrophages in the tumor microenvironment.

Cancer Res. 2013 Feb 22;

Authors: Dijkgraaf EM, Heusinkveld M, Tummers B, Vogelpoel LT, Goedemans R, Jha V, Nortier JW, Welters MJ, Kroep JR, van der Burg SH

Abstract
Current therapy of gynecological malignancies consists of platinum-containing chemotherapy. Resistance to therapy is associated with increased levels of interleukin-6 (IL-6) and prostaglandin E2 (PGE(2)), two inflammatory mediators known to skew differentiation of monocytes to tumor-promoting M2 macrophages. We investigated the impact of cisplatin and carboplatin on 10 different cervical and ovarian cancer cell lines as well as on the ability of the tumor cells to affect the differentiation and function of co-cultured monocytes in vitro. Treatment with cisplatin or carboplatin increased the potency of tumor cell lines to induce IL-10-producing M2 macrophages which displayed increased levels of activated signal transducer and activator of transcription-3 (STAT3) due to tumor-produced IL-6 as well as decreased levels of activated STAT1 and STAT6 related to the PGE(2)-production of tumor cells. Blockade of canonical NF?B signaling showed that the effect of the chemotherapy was abrogated, preventing the subsequent increased production of PGE(2) and/or IL-6 by the tumor cell lines. Treatment with the cyclooxygenase (COX)-inhibitor indomethacin and/or the clinical monoclonal antibody against IL-6 receptor (IL-6R), tocilizumab, prevented M2-differentiation. Importantly, no correlation existed between the production of PGE(2) or IL-6 by cancer cells and their resistance to chemotherapy-induced cell death, indicating that other mechanisms underlie the reported chemoresistance of tumors producing these factors. Our data suggests that a chemotherapy-mediated increase in tumor-promoting M2 macrophages may form an indirect mechanism for chemoresistance. Hence, concomitant therapy with COX-inhibitors and/or IL-6R antibodies might increase the clinical effect of platinum-based chemotherapy in otherwise resistant tumors.

PMID: 23436796 [PubMed - as supplied by publisher]

coxinhibitors c-met inhibitors zm-447439

Delayed developmental changes in neonatal vocalizations correlates with variations in ventral medial hypothalamus and central amygdala development in the rodent infant: effects of prenatal cocaine.

Related Articles

Delayed developmental changes in neonatal vocalizations correlates with variations in ventral medial hypothalamus and central amygdala development in the rodent infant: effects of prenatal cocaine.

Behav Brain Res. 2012 Dec 1;235(2):166-75

Authors: Cox ET, Hodge CW, Sheikh MJ, Abramowitz AC, Jones GF, Jamieson-Drake AW, Makam PR, Zeskind PS, Johns JM

Abstract
While variations in neonatal distress vocalizations have long been shown to reflect the integrity of nervous system development following a wide range of prenatal and perinatal insults, a paucity of research has explored the neurobiological basis of these variations. To address this, virgin Sprague-Dawley rats were bred and divided into three groups: [1] untreated, [2] chronic-cocaine treated (30 mg/kg/day, gestation days (GDs) 1-20); or [3] chronic saline treated (2 mg/kg/day, GDs 1-20). Pregnant dams were injected with Bromodeoxyuridine (10 mg/kg) on GDs 13-15 to label proliferating cells in limbic regions of interest. Ultrasonic vocalizations (USVs) were recorded on postnatal days (PNDs) 1, 14, and 21, from one male and female pup per litter. Variations in acoustic properties of USVs following cocaine-exposure were age and sex-dependent including measures of total number, total duration and amplitude of USVs, and percent of USVs with at least one harmonic. Following USV testing brains were stained with standard fluorescent immunohistochemistry protocols and examined for variations in neuronal development and if variations were associated with acoustic characteristics. Limbic region developmental differences following cocaine-exposure were sex- and age-dependent with variations in the ventral medial hypothalamus and central amygdala correlating with variations in vocalizations on PND 14 and 21. Results suggest maturation of the ventral medial hypothalamus and central amygdala may provide the basis for variations in the sound and production of USVs. As vocalizations may serve as a neurobehavioral marker for nervous system integrity, understanding the neurobiological basis of neonatal vocalizations may provide the basis for early intervention strategies in high-risk infant populations.

PMID: 22867871 [PubMed - indexed for MEDLINE]

zm-447439 rad001 ecdysone

The Combination of Sorafenib and Everolimus abrogates mTORC-1 and mTORC2 up-regulation in preclinical models of Osteosarcoma.

The Combination of Sorafenib and Everolimus abrogates mTORC-1 and mTORC2 up-regulation in preclinical models of Osteosarcoma.

Clin Cancer Res. 2013 Feb 22;

Authors: Pignochino Y, Dell'aglio C, Basirico M, Capozzi F, Soster M, Marchio S, Bruno S, Gammaitoni L, Sangiolo D, Torchiaro E, D'Ambrosio L, Fagioli F, Ferrari S, Alberghini M, Picci P, Aglietta M, Grignani G

Abstract
PURPOSE: The multikinase inhibitor sorafenib displays antitumor activity in preclinical models of osteosarcoma. However, in sorafenib-treated metastatic-relapsed osteosarcoma patients, disease stabilization and tumor shrinkage were short-lived and drug resistance occurred. We explored the sorafenib treatment escape mechanisms to overcome their drawbacks. Experimental design: Immunoprecipitation, Western blotting, and immunohistochemistry were employed to analyze the mammalian target of rapamycin (mTOR) pathway (mTORC1 and mTORC2). Cell viability, colony growth, and cell migration were evaluated in different osteosarcoma cell lines (MNNG-HOS, HOS, KHOS/NP, MG63, U-2OS, SJSA-1, SAOS-2) after scalar dose treatment with sorafenib (10-0.625 muM), rapamycin-analog everolimus (100-6.25 nM), and combinations of the two. Cell cycle, reactive oxygen species (ROS) production, and apoptosis were assessed by flow cytometry. NOD/SCID mice injected with MNNG-HOS cells were utilized to determine anti-tumor and anti-metastatic effects. Angiogenesis and vascularization were evaluated in vitro by exploiting endothelial branching morphogenesis assays and in vivo in xenografted mice and chorioallantoic membranes. RESULTS: After sorafenib treatment, mTORC1 signaling was reduced (downstream target P-S6) while mTORC2 was increased (phospho-mTOR Ser2481) in MNNG-HOS xenografts compared to vehicle-treated mice. Combining sorafenib with everolimus resulted in complete abrogation of both mTORC1 (through ROS-mediated AMPK activation) and mTORC2 (through complex disassembly). The sorafenib/everolimus combination yielded: 1) enhanced anti-proliferative and pro-apoptotic effects, 2) impaired tumor growth, 3) potentiated anti-angiogenesis, and 4) reduced migratory and metastatic potential. CONCLUSION: mTORC2 activation is an escape mechanism from sorafenib treatment. When sorafenib is combined with everolimus, its anti-tumor activity is increased by complete inhibition of the mTOR pathway in the preclinical setting.

PMID: 23434734 [PubMed - as supplied by publisher]

chir-258 dovitinib dna-pk

Everolimus in Advanced Pancreatic Neuroendocrine Tumors: The Clinical Experience.

Everolimus in Advanced Pancreatic Neuroendocrine Tumors: The Clinical Experience.

Cancer Res. 2013 Feb 22;

Authors: Yao JC, Phan AT, Jehl V, Shah G, Meric-Bernstam F

Abstract
The incidence of neuroendocrine tumors (NET) has increased dramatically in the past 30 years. This information has revitalized basic and clinical research into the molecular biology of NET and has resulted in the recent approval of new therapies for pancreatic NET (pNET), including the oral inhibitor of the mTOR everolimus. Everolimus significantly improved progression-free survival among patients with pNET in the phase III RADIANT-3 study. Here, we review the clinical studies showing the efficacy of everolimus in pNET and summarize the translational science from these studies. To understand the mechanisms of resistance and cause of treatment failure, we compared the type of progression events observed in the everolimus and placebo arms of the RADIANT-3 study. Comparison of the everolimus arm to the placebo arm indicated the fractions of progression events due to new metastasis only (21% vs. 22%), growth of preexisting lesions only (54% vs. 49%), and new metastasis along with growth of preexisting lesions (24% vs. 27%) were similar. These results suggest that although everolimus delays disease progression in patients with pNET, patients who experience disease progression while on everolimus do not appear to have a more aggressive metastatic phenotype than those whose disease progresses while on placebo. Cancer Res; 73(5); 1-5. �2013 AACR.

PMID: 23436795 [PubMed - as supplied by publisher]

ecdysone chir-258 dovitinib

Partial response of a rare malignant metastatic diffuse tenosynovial giant cell tumor with benign histologic features, treated with SCH 717-454, an insulin growth factor receptor inhibitor, in combination with everolimus, an MTOR inhibitor.

Partial response of a rare malignant metastatic diffuse tenosynovial giant cell tumor with benign histologic features, treated with SCH 717-454, an insulin growth factor receptor inhibitor, in combination with everolimus, an MTOR inhibitor.

Target Oncol. 2013 Feb 21;

Authors: Sikaria S, Heim-Hall J, Diaz EH, Williams R, Sankhala K, Laabs B, Mita M

PMID: 23430345 [PubMed - as supplied by publisher]

coxinhibitors c-met inhibitors zm-447439

Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.

Related Articles

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]

rad001 ecdysone chir-258

Regulation of Drosophila metamorphosis by xenobiotic response regulators.

Regulation of Drosophila metamorphosis by xenobiotic response regulators.

PLoS Genet. 2013 Feb;9(2):e1003263

Authors: Deng H, Kerppola TK

Abstract
Mammalian Nrf2-Keap1 and the homologous Drosophila CncC-dKeap1 protein complexes regulate both transcriptional responses to xenobiotic compounds as well as native cellular and developmental processes. The relationships between the functions of these proteins in xenobiotic responses and in development were unknown. We investigated the genes regulated by CncC and dKeap1 during development and the signal transduction pathways that modulate their functions. CncC and dKeap1 were enriched within the nuclei in many tissues, in contrast to the reported cytoplasmic localization of Keap1 and Nrf2 in cultured mammalian cells. CncC and dKeap1 occupied ecdysone-regulated early puffs on polytene chromosomes. Depletion of either CncC or dKeap1 in salivary glands selectively reduced early puff gene transcription. CncC and dKeap1 depletion in the prothoracic gland as well as cncC(K6/K6) and dKeap1(EY5/EY5) loss of function mutations in embryos reduced ecdysone-biosynthetic gene transcription. In contrast, dKeap1 depletion and the dKeap1(EY5/EY5) loss of function mutation enhanced xenobiotic response gene transcription in larvae and embryos, respectively. Depletion of CncC or dKeap1 in the prothoracic gland delayed pupation by decreasing larval ecdysteroid levels. CncC depletion suppressed the premature pupation and developmental arrest caused by constitutive Ras signaling in the prothoracic gland; conversely, constitutive Ras signaling altered the loci occupied by CncC on polytene chromosomes and activated transcription of genes at these loci. The effects of CncC and dKeap1 on both ecdysone-biosynthetic and ecdysone-regulated gene transcription, and the roles of CncC in Ras signaling in the prothoracic gland, establish the functions of these proteins in the neuroendocrine axis that coordinates insect metamorphosis.

PMID: 23408904 [PubMed - in process]

coxinhibitors c-met inhibitors zm-447439

Bilateral native kidney neoplasia detected by ultrasound in functionning renal allograft recipient.

Bilateral native kidney neoplasia detected by ultrasound in functionning renal allograft recipient.

Arch Ital Urol Androl. 2012 Dec;84(4):253-5

Authors: Noce A, Iaria G, Durante O, Sforza D, Canale MP, Di Villahermosa SM, Castagnola V, Tisone G, Di Daniele N

Abstract
We report the case of bilateral renal clear cell carcinoma in the native kidney, occurring fouryears after renal transplantation. Renal Doppler duplex sonography revealed large solid bilateral neoformation. Total-body computed tomography confirmed the presence of bilateral kidney lesions and also showed the presence of concomitant gross dyscariocinetic lesion of left hemotorax. The patient underwent bilateral native nephrectomy and the histological diagnosis was renal cell carcinoma. Subsequent left upper lobectomy revealed necrotic keratinizing squamous cell carcinoma. Then, the patients was switched tacrolimus to everolimus treatment and mycophenolate mofetil was reduced.

PMID: 23427757 [PubMed - in process]

dna-pk coxinhibitors c-met inhibitors

Regulation of Drosophila metamorphosis by xenobiotic response regulators.

Regulation of Drosophila metamorphosis by xenobiotic response regulators.

PLoS Genet. 2013 Feb;9(2):e1003263

Authors: Deng H, Kerppola TK

Abstract
Mammalian Nrf2-Keap1 and the homologous Drosophila CncC-dKeap1 protein complexes regulate both transcriptional responses to xenobiotic compounds as well as native cellular and developmental processes. The relationships between the functions of these proteins in xenobiotic responses and in development were unknown. We investigated the genes regulated by CncC and dKeap1 during development and the signal transduction pathways that modulate their functions. CncC and dKeap1 were enriched within the nuclei in many tissues, in contrast to the reported cytoplasmic localization of Keap1 and Nrf2 in cultured mammalian cells. CncC and dKeap1 occupied ecdysone-regulated early puffs on polytene chromosomes. Depletion of either CncC or dKeap1 in salivary glands selectively reduced early puff gene transcription. CncC and dKeap1 depletion in the prothoracic gland as well as cncC(K6/K6) and dKeap1(EY5/EY5) loss of function mutations in embryos reduced ecdysone-biosynthetic gene transcription. In contrast, dKeap1 depletion and the dKeap1(EY5/EY5) loss of function mutation enhanced xenobiotic response gene transcription in larvae and embryos, respectively. Depletion of CncC or dKeap1 in the prothoracic gland delayed pupation by decreasing larval ecdysteroid levels. CncC depletion suppressed the premature pupation and developmental arrest caused by constitutive Ras signaling in the prothoracic gland; conversely, constitutive Ras signaling altered the loci occupied by CncC on polytene chromosomes and activated transcription of genes at these loci. The effects of CncC and dKeap1 on both ecdysone-biosynthetic and ecdysone-regulated gene transcription, and the roles of CncC in Ras signaling in the prothoracic gland, establish the functions of these proteins in the neuroendocrine axis that coordinates insect metamorphosis.

PMID: 23408904 [PubMed - in process]

zm-447439 rad001 ecdysone

Partial response of a rare malignant metastatic diffuse tenosynovial giant cell tumor with benign histologic features, treated with SCH 717-454, an insulin growth factor receptor inhibitor, in combination with everolimus, an MTOR inhibitor.

Partial response of a rare malignant metastatic diffuse tenosynovial giant cell tumor with benign histologic features, treated with SCH 717-454, an insulin growth factor receptor inhibitor, in combination with everolimus, an MTOR inhibitor.

Target Oncol. 2013 Feb 21;

Authors: Sikaria S, Heim-Hall J, Diaz EH, Williams R, Sankhala K, Laabs B, Mita M

PMID: 23430345 [PubMed - as supplied by publisher]

zm-447439 rad001 ecdysone

Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.

Related Articles

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]

zm-447439 rad001 ecdysone

Inner nuclear envelope proteins SUN1 and SUN2 play a prominent role in the DNA damage response.

Related Articles

Inner nuclear envelope proteins SUN1 and SUN2 play a prominent role in the DNA damage response.

Curr Biol. 2012 Sep 11;22(17):1609-15

Authors: Lei K, Zhu X, Xu R, Shao C, Xu T, Zhuang Y, Han M

Abstract
The DNA damage response (DDR) and DNA repair are critical for maintaining genomic stability and evading many human diseases. Recent findings indicate that accumulation of SUN1, a nuclear envelope (NE) protein, is a significant pathogenic event in Emery-Dreifuss muscular dystrophy and Hutchinson-Gilford progeria syndrome, both caused by mutations in LMNA. However, roles of mammalian SUN proteins in mitotic cell division and genomic stability are unknown. Here we report that the inner NE proteins SUN1 and SUN2 may play a redundant role in DDR. Mouse embryonic fibroblasts from Sun1(-/-)Sun2(-/-) mice displayed premature proliferation arrest in S phase of cell cycle, increased apoptosis and DNA damage, and decreased perinuclear heterochromatin, indicating genome instability. Furthermore, activation of ATM and H2A.X, early events in DDR, were impaired in Sun1(-/-)Sun2(-/-) fibroblasts. A biochemical screen identified interactions between SUN1 and SUN2 and DNA-dependent protein kinase (DNAPK) complex that functions in DNA nonhomologous end joining repair and possibly in DDR. Knockdown of DNAPK reduced ATM activation in NIH 3T3 cells, consistent with a potential role of SUN1- and SUN2-DNAPK interaction during DDR. SUN1 and SUN2 could affect DDR by localizing certain nuclear factors to the NE or by mediating communication between nuclear and cytoplasmic events.

PMID: 22863315 [PubMed - indexed for MEDLINE]

dna-pk coxinhibitors c-met inhibitors

Image-based high-throughput screening for inhibitors of angiogenesis.

Related Articles

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]

chir-258 dovitinib dna-pk

Bilateral native kidney neoplasia detected by ultrasound in functionning renal allograft recipient.

Bilateral native kidney neoplasia detected by ultrasound in functionning renal allograft recipient.

Arch Ital Urol Androl. 2012 Dec;84(4):253-5

Authors: Noce A, Iaria G, Durante O, Sforza D, Canale MP, Di Villahermosa SM, Castagnola V, Tisone G, Di Daniele N

Abstract
We report the case of bilateral renal clear cell carcinoma in the native kidney, occurring fouryears after renal transplantation. Renal Doppler duplex sonography revealed large solid bilateral neoformation. Total-body computed tomography confirmed the presence of bilateral kidney lesions and also showed the presence of concomitant gross dyscariocinetic lesion of left hemotorax. The patient underwent bilateral native nephrectomy and the histological diagnosis was renal cell carcinoma. Subsequent left upper lobectomy revealed necrotic keratinizing squamous cell carcinoma. Then, the patients was switched tacrolimus to everolimus treatment and mycophenolate mofetil was reduced.

PMID: 23427757 [PubMed - in process]

dna-pk coxinhibitors c-met inhibitors