5-alpha-reductase

Reversible acute encephalopathy with mutism, induced by calcineurin inhibitors after renal transplantation.

Reversible acute encephalopathy with mutism, induced by calcineurin inhibitors after renal transplantation.

J Nephrol. 2012 Sep-Oct;25(5):839-42

Authors: Toledo Perdomo K, Navarro Cabello MD, P�rez S�ez MJ, Ramos P�rez MJ, Ag�era Morales ML, Aljama Garc�a P

Abstract
The incidence of neurotoxicity from calcineurin inhibitors varies by the organ transplanted. Akinetic mutism is characterized by the inability to perform voluntary movements and express language, without alterations in mental status. This process has been reported in neurotoxicity due to high serum levels of calcineurin inhibitors, but in rare cases, it presents as a form of tacrolimus toxicity after renal transplantation, despite normal serum levels. We report a clinical case of a renal transplant patient in whom reversible acute encephalopathy and akinetic mutism developed. Brain lesions appeared on magnetic resonance imaging, and the condition resolved after the drug was withdrawn.

PMID: 22252846 [PubMed - indexed for MEDLINE]

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

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

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

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]

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

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

PMID: 22863315 [PubMed - indexed for MEDLINE]

2013年2月22日星期五

Cassia tora L. (Jue-ming-zi) has anticancer activity in TCA8113 cells in vitro and exerts anti-metastatic effects in vivo.

Cassia tora L. (Jue-ming-zi) has anticancer activity in TCA8113 cells in vitro and exerts anti-metastatic effects in vivo.

Oncol Lett. 2013 Mar;5(3):1036-1042

Authors: Zhao X, Wang Q, Qian Y, Pang L

Abstract
Cassia tora L. (Jue-ming-zi) is a traditional Chinese medicine widely used in East Asia. The in vitro anticancer effects of Jue-ming-zi were evaluated in TCA8113 human tongue carcinoma cells using a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. At a concentration of 1.0 mg/ml, Cassia tora L. inhibited the growth of TCA8113 cells by 72%; this inhibiton was greater than that by 0.5 and 0.25 mg/ml Cassia tora L. (43 and 16%, respectively). To elucidate the inhibitory mechanisms underlying the anticancer effect of Cassia tora L. in cancer cells, the expression of genes associated with apoptosis, inflammation and metastasis were measured using RT-PCR and western blot analysis. Cassia tora L. significantly induced apoptosis in cancer cells (P<0.05) by upregulating Bax, caspase-3 and caspase-9, and by downregulating Bcl-2. The expression of genes associated with inflammation, including NF-?B, iNOS and COX-2, was significantly downregulated (P<0.05) by Cassia tora L., demonstrating its anti-inflammatory properties. Cassia tora L. also exerted a significant anti-metastatic effect on cancer cells as demonstrated by decreased mRNA expression of matrix metalloprotease (MMP) genes and increased expression of tissue inhibitors of metalloproteinases (TIMPs), and as confirmed by the inhibition of induced tumor metastasis induced in 26-M3.1 colon cells in BALB/c mice. Our results demonstrated that Cassia tora L. exhibited the most potent in vitro anticancer effects, induced apoptosis, had anti-inflammatory activities and exerted in vivo anti-metastatic effects. Additionally, the anticancer, anti-inflammatory and anti-metastatic effects of the higher Cassia tora L. concentrations were stronger compared with those of the lower Cassia tora L. concentrations tested.

PMID: 23426077 [PubMed - as supplied by publisher]

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

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

Methods Mol Biol. 2013;931:139-51

Authors: Evensen L, Link W, Lorens JB

PMID: 23027002 [PubMed - indexed for MEDLINE]

coxinhibitors c-met inhibitors zm-447439

Long-term outcome of second-generation everolimus-eluting stents and Endeavor zotarolimus-eluting stents in a prospective registry of ST-elevation myocardial infarction patients.

Long-term outcome of second-generation everolimus-eluting stents and Endeavor zotarolimus-eluting stents in a prospective registry of ST-elevation myocardial infarction patients.

EuroIntervention. 2013 Feb 22;8(10):1199-206

Authors: Velders MA, Boden H, van der Hoeven BL, Liem SS, Atary JZ, van der Wall EE, Jukema JW, Schalij MJ

Abstract
Aims: The optimal drug-eluting stent (DES) in ST-elevation myocardial infarction (STEMI) patients remains unclear. We sought to compare the long-term performance of everolimus-eluting stents (EES) and Endeavor zotarolimus-eluting stents (E-ZES) in STEMI. Methods and results: The current analysis of a prospective registry included consecutive patients treated with EES or E-ZES for STEMI. Adjustment for measured confounders was done using Cox regression. In total, 931 patients met the inclusion criteria (412 EES and 519 E-ZES). Baseline characteristics were balanced, apart from a lower rate of renal insufficiency in EES. Median follow-up duration was 2.4 years (IQR 1.6-3.1). Mortality outcomes were similar. Up to three-year follow-up, the composite endpoint of cardiac death, target vessel-related myocardial infarction and target lesion revascularisation (TLR) was lower in EES; 9.7% vs. 13.7% in E-ZES (HR 0.64, 95% CI: 0.42-0.99), primarily driven by reduced TLR rates; 3.4% in EES vs. 7.3% in E-ZES (HR 0.46, 95% CI: 0.23-0.92). Definite stent thrombosis rates were low and similar between groups (1.1% in EES vs. 1.9% in E-ZES, p=0.190). Conclusions: Use of EES led to lower rates of the composite endpoint, driven by reduced TLR. This suggests that EES are more efficacious than Endeavor ZES in STEMI. Definite ST rates were low, and the strategy of second-generation DES implantation and the administration of upfront GP IIb/IIIa inhibitors appear to be safe in STEMI.

PMID: 23425544 [PubMed - in process]

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

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

PMID: 22863315 [PubMed - indexed for MEDLINE]

c-met inhibitors zm-447439 rad001

Mapping inhibitor binding modes on an active cysteine protease via nuclear magnetic resonance spectroscopy.

Mapping inhibitor binding modes on an active cysteine protease via nuclear magnetic resonance spectroscopy.

Biochemistry. 2012 Dec 18;51(50):10087-98

Authors: Lee GM, Balouch E, Goetz DH, Lazic A, McKerrow JH, Craik CS

Abstract
Cruzain is a member of the papain/cathepsin L family of cysteine proteases, and the major cysteine protease of the protozoan Trypanosoma cruzi, the causative agent of Chagas disease. We report an autoinduction methodology that provides soluble cruzain in high yields (>30 mg/L in minimal medium). These increased yields provide sufficient quantities of active enzyme for use in nuclear magnetic resonance (NMR)-based ligand mapping. Using circular dichroism and NMR spectroscopy, we also examined the solution-state structural dynamics of the enzyme in complex with a covalently bound vinyl sulfone inhibitor (K777). We report the backbone amide and side chain carbon chemical shift assignments of cruzain in complex with K777. These resonance assignments were used to identify and map residues located in the substrate binding pocket, including the catalytic Cys25 and His162. Selective [(15)N]Cys, [(15)N]His, and [(13)C]Met labeling was performed to quickly assess cruzain-ligand interactions for a set of eight low-molecular weight compounds exhibiting micromolar binding or inhibition. Chemical shift perturbation mapping verified that six of the eight compounds bind to cruzain at the active site. Three different binding modes were delineated for the compounds, namely, covalent, noncovalent, and noninteracting. These results provide examples of how NMR spectroscopy can be used to screen compounds for fast evaluation of enzyme-inhibitor interactions to facilitate lead compound identification and subsequent structural studies.

PMID: 23181936 [PubMed - indexed for MEDLINE]

2013年2月21日星期四

Outcomes of pseudo-severe aortic stenosis under conservative treatment.

Outcomes of pseudo-severe aortic stenosis under conservative treatment.

Eur Heart J. 2012 Oct;33(19):2426-33

Authors: Foug�res E, Tribouilloy C, Monchi M, Petit-Eisenmann H, Baleynaud S, Pasquet A, Chauvel C, Metz D, Adams C, Rusinaru D, Gu�ret P, Monin JL

Abstract
AIMS: In the setting of low-flow/low-gradient aortic stenosis (LF/LGAS), outcomes of pseudo-severe aortic stenosis (AS) remain poorly described. This study was aimed to assess the outcome of patients with pseudo-severe AS under conservative treatment.
METHODS AND RESULTS: Among 305 patients from the European Registry of LF/LGAS, the outcomes of the 107 patients followed under conservative treatment were analysed. Based on the results of dobutamine echocardiography, patients were divided into group IA [left ventricular (LV) contractile reserve present with true-severe AS, n = 43], group IB [pseudo-severe AS (n = 29) defined as LV contractile reserve with a final aortic valve area ?1.2 cm(2) and a mean transaortic pressure gradient <40 mmHg at peak dobutamine infusion], or group II (exhausted LV contractile reserve, n = 35). The rate of death within 5 years was significantly lower in the group IB (43 � 11%, n = 10), when compared with the group IA (91 � 6%, n = 33; P = 0.001) and the group II (100%, n = 23; P < 0.001). The Cox proportional hazard model analysis demonstrated that the hazard ratio for death in the group IB remained significantly lower than in the other groups, even after adjustment for currently established risk factors. Furthermore, the 5-year survival of pseudo-severe AS patients was comparable with that of propensity-matched patients with systolic heart failure and no evidence of valve disease.
CONCLUSION: In patients with pseudo-severe AS, the 5-year survival under conservative treatment is better than in true-severe AS and comparable with that of propensity-matched patients with LV systolic dysfunction and no evidence of valve disease. Further studies are needed to define optimal therapeutic management in these patients.

PMID: 22733832 [PubMed - indexed for MEDLINE]

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

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

Methods Mol Biol. 2013;931:139-51

Authors: Evensen L, Link W, Lorens JB

PMID: 23027002 [PubMed - indexed for MEDLINE]

Single-cell microarray enables high-throughput evaluation of DNA double-strand breaks and DNA repair inhibitors.

Single-cell microarray enables high-throughput evaluation of DNA double-strand breaks and DNA repair inhibitors.

Cell Cycle. 2013 Feb 19;12(6)

Authors: Weingeist DM, Ge J, Wood DK, Mutamba JT, Huang Q, Rowland EA, Yaffe MB, Floyd S, Engelward BP

Abstract
A key modality of non-surgical cancer management is DNA damaging therapy that causes DNA double-strand breaks that are preferentially toxic to rapidly dividing cancer cells. Double-strand break repair capacity is recognized as an important mechanism in drug resistance and is therefore a potential target for adjuvant chemotherapy. Additionally, spontaneous and environmentally induced DSBs are known to promote cancer, making DSB evaluation important as a tool in epidemiology, clinical evaluation and in the development of novel pharmaceuticals. Currently available assays to detect double-strand breaks are limited in throughput and specificity and offer minimal information concerning the kinetics of repair. Here, we present the CometChip, a 96-well platform that enables assessment of double-strand break levels and repair capacity of multiple cell types and conditions in parallel and integrates with standard high-throughput screening and analysis technologies. We demonstrate the ability to detect multiple genetic deficiencies in double-strand break repair and evaluate a set of clinically relevant chemical inhibitors of one of the major double-strand break repair pathways, non-homologous end-joining. While other high-throughput repair assays measure residual damage or indirect markers of damage, the CometChip detects physical double-strand breaks, providing direct measurement of damage induction and repair capacity, which may be useful in developing and implementing treatment strategies with reduced side effects.

PMID: 23422001 [PubMed - as supplied by publisher]

High MET expression is an adverse prognostic factor in patients with triple-negative breast cancer.

High MET expression is an adverse prognostic factor in patients with triple-negative breast cancer.

Br J Cancer. 2013 Feb 19;

Authors: Zagouri F, Bago-Horvath Z, R�ssler F, Brandstetter A, Bartsch R, Papadimitriou CA, Dimitrakakis C, Tsigginou A, Papaspyrou I, Giannos A, Dimopoulos MA, Filipits M

Abstract
Background:The mesenchymal-epithelial transition (MET) pathway is frequently altered in tumours. The purpose of our study was to determine the prognostic value of tumour MET expression levels in patients with triple-negative breast cancer (TNBC), in order to strengthen the rationale for targeted therapy of TNBC using MET inhibitors.Methods:We determined expression of MET in formalin-fixed paraffin-embedded surgical specimens of TNBC by immunohistochemistry. Recurrence-free and overall survival was analysed with Cox models adjusted for clinical and pathological factors.Results:Immunostaining for MET was classified as high in 89 of 170 (52%) tumours. MET expression was more frequently observed in G3 carcinomas (P=0.02) but was not significantly associated to any of the other clinical or pathological parameters. High MET expression predicted shorter survival of the patients. Multivariate Cox proportional hazards regression analyses identified MET to be an independent prognostic factor for recurrence (adjusted hazard ratio (HR) for recurrence 3.43; 95% confidence interval (CI) 1.65-7.12; P=0.001) and death (adjusted HR for death 3.74; 95% CI 1.65-8.46; P=0.002).Conclusion:These results provide further evidence that the MET pathway could be exploited as a target for TNBC.British Journal of Cancer advance online publication, 19 February 2013; doi:10.1038/bjc.2013.31 www.bjcancer.com.

PMID: 23422757 [PubMed - as supplied by publisher]

Optimizing megakaryocyte polyploidization by targeting multiple pathways of cytokinesis.

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]

2013年2月20日星期三

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]

PI3K/Akt/mTOR Pathway Inhibitors in the Therapy of Pancreatic Neuroendocrine Tumors.

PI3K/Akt/mTOR Pathway Inhibitors in the Therapy of Pancreatic Neuroendocrine Tumors.

Cancer Lett. 2013 Feb 15;

Authors: Wolin EM

Abstract
The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is implicated in the pathogenesis of pancreatic neuroendocrine tumors (pNETs). Activation of this pathway is driven by aberrant tyrosine kinase receptor activities. Mutations in the PI3K/Akt/mTOR pathway occur in 15% of pNETs, and expression of genes of the PI3K/Akt/mTOR pathway is altered in the majority of pNETs. The mTOR inhibitor everolimus has been approved by the FDA for the treatment of pNET, but its efficacy may be limited by its inability to prevent mTORC2-mediated activation of Akt. Specific inhibitors of PI3K, Akt, or other pathway nodes, and their concomitant use with mTOR inhibitors, or agents with dual activity, may be more effective. Preclinical studies demonstrate that inhibitors of the PI3K pathway have antitumor activity in pNET cells, either through direct inhibition of individual pathway nodes or indirect inhibition of molecular chaperones such as heat-shock protein 90. Clinical studies are underway evaluating individual node and dual node inhibitors.

PMID: 23419523 [PubMed - as supplied by publisher]

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

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

Methods Mol Biol. 2013;931:139-51

Authors: Evensen L, Link W, Lorens JB

PMID: 23027002 [PubMed - indexed for MEDLINE]

coxinhibitors c-met inhibitors zm-447439

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

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

Methods Mol Biol. 2013;931:139-51

Authors: Evensen L, Link W, Lorens JB

PMID: 23027002 [PubMed - indexed for MEDLINE]

2013年2月19日星期二

A catalytically-inactive snake venom Lys49 phospholipase A(2) homologue induces expression of cyclooxygenase-2 and production of prostaglandins through selected signaling pathways in macrophages.

A catalytically-inactive snake venom Lys49 phospholipase A(2) homologue induces expression of cyclooxygenase-2 and production of prostaglandins through selected signaling pathways in macrophages.

Eur J Pharmacol. 2013 Feb 14;

Authors: Moreira V, de Castro Souto PC, Ramirez Vinolo MA, Lomonte B, Mar�a Guti�rrez J, Curi R, Teixeira C

Abstract
The effects of a snake venom Lys-49 phospholipase A(2) (PLA(2)) homologue named MT-II, devoid of enzymatic activity, on the biosynthesis of prostaglandins and protein expression of cyclooxygenase-2 (COX-2) and signaling pathways involved were evaluated in mouse macrophages in culture and in peritoneal cells ex vivo. Stimulation of macrophages with MT-II leads to production of prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)) and protein expression of COX-2 and microsomal prostaglandin E synthase-1 (mPGES-1). Inhibition of cytosolic PLA(2) (cPLA(2)), but not Ca(+2) independent PLA(2) (iPLA(2)) reduced release of PGD(2) and PGE(2) and expression of COX-2 induced by MT-II. Inhibition of nuclear factor ?B (NF-?B) significantly reduced MT-II-induced PGE(2), but not PGD(2) production and COX-2 expression. Inhibitors of either protein kinase C (PKC), protein tyrosine kinase (PTK), or extracellular signal-regulated kinase (ERK) pathways abrogated MT-II-induced NF-?B activation and reduced COX-2 expression and PGE(2) release, whereas the p38 mitogen-activated protein kinase (MAPK) inhibitor reduced MT-II-induced COX-2 expression and PGD(2) production. Inhibition of phosphatidylinositol-3-kinase (PI3K) pathway abrogated MT-II-induced NF-?B activation, but affected neither prostaglandins production nor COX-2 expression. MT-II-induced production of PGD(2) and PGE(2) and COX-2 expression were also observed in vivo after intraperitoneal injection into mice. Collectively, our data demonstrate that a catalytically-inactive PLA(2) homologue is capable of inducing prostaglandins biosynthesis and COX-2 expression in macrophages in both in vitro and in vivo models, indicating that the enzymatic activity of PLA(2) is not necessary to trigger these effects. MT-II-activated NF-?B, cPLA(2) and distinct protein kinases are the principal steps involved in these cellular events.

PMID: 23416211 [PubMed - as supplied by publisher]

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

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

PMID: 23400739 [PubMed - in process]

Activity of the Heat Shock Protein 90 Inhibitor Ganetespib in Melanoma.

Activity of the Heat Shock Protein 90 Inhibitor Ganetespib in Melanoma.

PLoS One. 2013;8(2):e56134

Authors: Wu X, Marmarelis ME, Hodi FS

Abstract
Heat shock protein 90 (HSP90) is involved in the regulation of diverse biological processes such as cell signaling, proliferation and survival, and has been recently recognized as a potential target for cancer therapy. Ganetespib is a potent ATP competitive inhibitor of HSP90. Ganetespib downregulated the expression of multiple signal transducing molecules including EGFR, IGF-1R, c-Met, Akt, B-RAF and C-RAF, resulting in pronounced decrease in phosphorylation of Akt and Erk1/2 in a panel of five cutaneous melanoma cell lines including those harboring B-RAF and N-RAS mutations. Ganetespib exhibited potent antiproliferative activity on all five of these cell lines, with IC50 values between 37.5 and 84 nM. Importantly, Ganetespib is active on B-RAF mutated melanoma cells that have acquired resistance to B-RAF inhibition. Ganetespib induced apoptosis and cell cycle arrest at G1 and/or G2/M phase. Ganetespib induced cell cycle arrest was accompanied by altered expression of cyclin-dependent kinase inhibitor (CDKI) p21(Cip1) and p27(Kip1), cyclins B1, D1 and E, and/or cyclin-dependent kinases 1, 2 and 4. HSP90 is functionally important for melanoma cells and HSP90 inhibitors such as ganetespib could potentially be effective therapeutics for melanoma with various genetic mutations and acquired resistance to B-RAF inhibition.

PMID: 23418523 [PubMed - as supplied by publisher]

c-met inhibitors zm-447439 rad001

An inverse switch in DNA base excision and strand break repair contributes to melphalan resistance in multiple myeloma cells.

An inverse switch in DNA base excision and strand break repair contributes to melphalan resistance in multiple myeloma cells.

PLoS One. 2013;8(2):e55493

Authors: Sousa MM, Zub KA, Aas PA, Hanssen-Bauer A, Demirovic A, Sarno A, Tian E, Liabakk NB, Slupphaug G

Abstract
Alterations in checkpoint and DNA repair pathways may provide adaptive mechanisms contributing to acquired drug resistance. Here, we investigated the levels of proteins mediating DNA damage signaling and -repair in RPMI8226 multiple myeloma cells and its Melphalan-resistant derivative 8226-LR5. We observed markedly reduced steady-state levels of DNA glycosylases UNG2, NEIL1 and MPG in the resistant cells and cross-resistance to agents inducing their respective DNA base lesions. Conversely, repair of alkali-labile sites was apparently enhanced in the resistant cells, as substantiated by alkaline comet assay, autoribosylation of PARP-1, and increased sensitivity to PARP-1 inhibition by 4-AN or KU58684. Reduced base-excision and enhanced single-strand break repair would both contribute to the observed reduction in genomic alkali-labile sites, which could jeopardize productive processing of the more cytotoxic Melphalan-induced interstrand DNA crosslinks (ICLs). Furthermore, we found a marked upregulation of proteins in the non-homologous end-joining (NHEJ) pathway of double-strand break (DSB) repair, likely contributing to the observed increase in DSB repair kinetics in the resistant cells. Finally, we observed apparent upregulation of ATR-signaling and downregulation of ATM-signaling in the resistant cells. This was accompanied by markedly increased sensitivity towards Melphalan in the presence of ATR-, DNA-PK, or CHK1/2 inhibitors whereas no sensitizing effect was observed subsequent to ATM inhibition, suggesting that replication blocking lesions are primary triggers of the DNA damage response in the Melphalan resistant cells. In conclusion, Melphalan resistance is apparently contributed by modulation of the DNA damage response at multiple levels, including downregulation of specific repair pathways to avoid repair intermediates that could impair efficient processing of cytotoxic ICLs and ICL-induced DSBs. This study has revealed several novel candidate biomarkers for Melphalan sensitivity that will be included in targeted quantitation studies in larger patient cohorts to validate their value in prognosis as well as targets for replacement- or adjuvant therapies.

PMID: 23405159 [PubMed - in process]

chir-258 dovitinib

2013年2月18日星期一

mTORC1 Inhibitors Suppress Meningioma Growth in Mouse Models.

mTORC1 Inhibitors Suppress Meningioma Growth in Mouse Models.

Clin Cancer Res. 2013 Feb 13;

Authors: Pachow D, Andrae N, Kliese N, Angenstein F, Stork O, Wilisch-Neumann A, Kirches E, Mawrin C

Abstract
PURPOSE: To evaluate the mTORC1 (mammalian target of rapamycin complex 1) pathway in meningiomas and to explore mTORC1 as a therapeutic target in meningioma cell lines and mouse models.EXPERIMENTAL DESIGN: Tissue microarrays (53 meningiomas of all WHO grades) were stained for phosphorylated polypeptides of mTOR, Akt, and the mTORC1 targets 4EBP1 and p70S6K, the latter being the consensus marker for mTORC1 activity. Expression of proteins and mRNAs was assessed by Western blotting and real-time PCR in 25 tumors. Cell lines Ben-Men-1 (benign), IOMM-Lee and KT21 (malignant), and pairs of merlin-positive or -negative meningioma cells were used to assess sensitivity toward mTORC1 inhibitors in methyl-tetrazolium and bromodeoxyuridine (BrdUrd) assays. The effect of temsirolimus (20 mg/kg daily) on tumor weight or MRI-estimated tumor volume was tested by treatment of eight nude mice (vs. 7 controls) carrying subcutaneous IOMM-Lee xenografts, or of eight (5) mice xenotransplanted intracranially with IOMM-Lee (KT21) cells in comparison to eight (5) untreated controls.RESULTS: All components of the mTORC1 pathway were expressed and activated in meningiomas, independent of their WHO grade. A significant dosage-dependent growth inhibition by temsirolimus and everolimus was observed in all cell lines. It was slightly diminished by merlin loss. In the orthotopic and subcutaneous xenograft models, temsirolimus treatment resulted in about 70% growth reduction of tumors (P < 0.01), which was paralleled by reduction of Ki67 mitotic index (P < 0.05) and reduction of mTORC1 activity (p70S6K phosphorylation) within the tumors.CONCLUSION: mTORC1 inhibitors suppress meningioma growth in mouse models, although the present study did not measure survival. Clin Cancer Res; 1-10. �2012 AACR.

PMID: 23406776 [PubMed - as supplied by publisher]

Rationally Designed Multitarget Agents against Inflammation and Pain.

Rationally Designed Multitarget Agents against Inflammation and Pain.

Curr Med Chem. 2013 Feb 14;

Authors: Hwang SH, Wecksler AT, Wagner K, Hammock BD

Abstract
Arachidonic acid (ARA) undergoes enzyme-mediated oxidative metabolism, resulting in the formation of a number of biologically active metabolites. For over a century, these biochemical transformations have been the target of numerous pharmacological drugs for inflammation and pain. In particular, non-steroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 (COX-2) selective inhibitors (coxibs) are widely used in the treatment of inflammation and pain. However, gastrointestinal (GI) and cardiovascular adverse effects of NSAIDs and coxibs, and recent findings demonstrating there are significant risks from the disruption of oxylipin levels when pharmacologically inhibiting a single ARA cascade metabolic pathway have led to studies involving the simultaneous inhibition of multiple pathways in ARA cascade. These studies suggest that multitarget inhibition represents a new and valuable option to enhance efficacy or reduce side-effects in the treatment of inflammation and pain. This review focuses on the crosstalk within the three pathways of the ARA cascade (cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP450)), and summarizes the current and future approaches of multitarget inhibitors for the treatment of eicosanoid driven inflammation and pain.

PMID: 23410172 [PubMed - as supplied by publisher]

chir-258 dovitinib dna-pk

Clinicopathological significance of Polo-like kinase 1 (PLK1) expression in human malignant glioma.

Clinicopathological significance of Polo-like kinase 1 (PLK1) expression in human malignant glioma.

Acta Histochem. 2012 Sep;114(5):503-9

Authors: Cheng MW, Wang BC, Weng ZQ, Zhu XW

Abstract
Polo-like kinase 1 (PLK1), a variety of serine/threonine-protein kinase, has been reported to play important roles in malignant transformation. The purpose of this study was to investigate the clinicopathological significance of PLK1 expression in malignant glioma. A semi-quantitative RT-PCR assay was performed to detect the expression of PLK1 mRNA in 68 cases of glioma tissues and corresponding non-cancerous brain tissues. Additionally, the correlation of PLK1 mRNA expression with clinicopathological factors or prognosis of glioma patients was statistically analyzed. Multivariate analysis of prognostic factors was performed using the Cox proportional hazard model. Small interfering RNA was used to knockdown PLK1 expression in a glioma cell line and analyze the effects of PLK1 inhibition on growth, cell cycle, apoptosis and chemo- or radiosensitivity of glioma cells. Results showed that the expression of PLK1 mRNA was significantly higher in glioma tissues than in corresponding normal brain tissues. The expression of PLK1 mRNA was closely correlated with WHO grade, KPS and tumor recurrence of glioma patients (P=0.022, 0.030 and 0.041, respectively). Meanwhile, the disease-free and overall survival rates of patients with high PLK1 mRNA expression were obviously lower than those of patients with low PLK1 mRNA expression. Multivariate analysis showed that high PLK1 mRNA expression was a poor prognostic factor for glioma patients (P=0.028). The expression of PLK1 mRNA and protein was significantly down-regulated in stably transfected U251-S cells. PLK1 down-regulation could inhibit growth, induce cell arrest in G2/M phase of cell cycle and apoptosis enhancement in glioma cells. Further, PLK1 down-regulation could enhance the sensitivity of glioma cells to cisplatin or irradiation. Thus, the status of PLK1 mRNA expression might be an independent prognostic factor for glioma patients and targeting PLK1 could be a novel strategy for chemo- or radiosensitization of human malignant gliomas.

PMID: 22000864 [PubMed - indexed for MEDLINE]

c-met inhibitors zm-447439 rad001

A phase 1 study of everolimus plus docetaxel plus cisplatin as induction chemotherapy for patients with locally and/or regionally advanced head and neck cancer.

A phase 1 study of everolimus plus docetaxel plus cisplatin as induction chemotherapy for patients with locally and/or regionally advanced head and neck cancer.

Cancer. 2013 Feb 13;

Authors: Fury MG, Sherman E, Ho AL, Xiao H, Tsai F, Nwankwo O, Sima C, Heguy A, Katabi N, Haque S, Pfister DG

Abstract
BACKGROUND: Activation of the phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is common in head and neck cancers, and it has been demonstrated that inhibition of mTOR complex 1 sensitizes cell lines to platinum and taxane chemotherapy. The authors conducted a phase 1 study to evaluate the addition of oral everolimus to cisplatin and docetaxel as induction chemotherapy for head and neck cancer. METHODS: In this single-institution phase 1 study, 3 doses of daily everolimus were explored: 5 mg daily, 7.5 mg daily (administered as 5 mg daily alternating with 10 mg daily), and 10 mg daily of each 21-day cycle. Cisplatin and docetaxel doses were fixed (both were 75 mg/m(2) on day 1 of 21-day cycle) at each dose level with pegfilgrastim support. A standard 3 + 3 dose-escalation plan was used. After induction, patients were removed from protocol. RESULTS: Eighteen patients were enrolled (15 men, 3 women), and their median Karnofsky performance status was 90. The most common toxicities were hyperglycemia, low hemoglobin, fatigue, and thrombocytopenia. Dose-limiting toxicities (DLTs) were neutropenic fever (1 event at dose level 2, 2 events at dose level 3), and all patients recovered fully from these DLTs. The maximum tolerated dose was exceeded at dose level 3. The progression-free survival rate at 1 year was 87.5% (95% confidence interval, 56.8%-96.7%); and, at 2 years, it was 76.6% (95% confidence interval, 41.2%-92.3%). Activating PI3K catalytic subunit ? (PIK3CA) gene mutations were identified in 2 human papillomavirus-associated oropharyngeal cancers. CONCLUSIONS: The phase 2 recommended dose was 7.5 mg daily for everolimus plus cisplatin and docetaxel (both at 75 mg/m(2) on day 1 of a 21-day cycle) given with pegfilgrastim support. Cancer 2013;. � 2013 American Cancer Society.

PMID: 23408298 [PubMed - as supplied by publisher]

The mTOR pathway in hepatic malignancies.

The mTOR pathway in hepatic malignancies.

Hepatology. 2013 Feb 13;

Authors: Bhat M, Sonenberg N, Gores G

Abstract
The mechanistic/mammalian target of rapamycin (mTOR) pathway plays a critical role in cellular metabolism, growth and proliferation, and has been evaluated as a target for therapy in various malignancies. The mTOR pathway is a major tumor-initiating pathway in hepatocellular carcinoma, with upregulation seen in up to 50% of (HCC) tumors. Metformin, which represses mTOR signaling by activating AMPK, has been shown to decrease liver carcinogenesis in population studies. mTOR inhibitors such as everolimus have been evaluated as adjunctive chemotherapy with some success, although efficacy has been limited by the lack of complete mTOR pathway inhibition. The active site mTOR inhibitors hold greater promise, given that they offer complete mTOR suppression. There is also evidence of mTOR pathway activation in cholangiocarcinoma, although its biological significance in initiating and promoting tumor progression remains ambiguous. This review article provides an overview of the complex biochemistry behind the mTOR pathway and its role in carcinogenesis, especially as it pertains to hepatic malignancies. (HEPATOLOGY 2013.).

PMID: 23408390 [PubMed - as supplied by publisher]

2013年2月17日星期日

The mTOR pathway in hepatic malignancies.

The mTOR pathway in hepatic malignancies.

Hepatology. 2013 Feb 13;

Authors: Bhat M, Sonenberg N, Gores G

PMID: 23408390 [PubMed - as supplied by publisher]

Discovery of an Orally Available, Brain Penetrant BACE1 Inhibitor that Affords Robust CNS A? Reduction.

Discovery of an Orally Available, Brain Penetrant BACE1 Inhibitor that Affords Robust CNS A? Reduction.

ACS Med Chem Lett. 2012 Nov 8;3(11):897-902

Authors: Stamford AW, Scott JD, Li SW, Babu S, Tadesse D, Hunter R, Wu Y, Misiaszek J, Cumming JN, Gilbert EJ, Huang C, McKittrick BA, Hong L, Guo T, Zhu Z, Strickland C, Orth P, Voigt JH, Kennedy ME, Chen X, Kuvelkar R, Hodgson R, Hyde LA, Cox K, Favreau L, Parker EM, Greenlee WJ

Abstract
Inhibition of BACE1 to prevent brain A? peptide formation is a potential disease-modifying approach to the treatment of Alzheimer's disease. Despite over a decade of drug discovery efforts, the identification of brain-penetrant BACE1 inhibitors that substantially lower CNS A? levels following systemic administration remains challenging. In this report we describe structure-based optimization of a series of brain-penetrant BACE1 inhibitors derived from an iminopyrimidinone scaffold. Application of structure-based design in tandem with control of physicochemical properties culminated in the discovery of compound 16, which potently reduced cortex and CSF A?40 levels when administered orally to rats.

PMID: 23412139 [PubMed - as supplied by publisher]

chir-258 dovitinib dna-pk

Association of integrin beta1 and c-MET in mediating EGFR TKI gefitinib resistance in non-small cell lung cancer.

Association of integrin beta1 and c-MET in mediating EGFR TKI gefitinib resistance in non-small cell lung cancer.

Cancer Cell Int. 2013 Feb 13;13(1):15

Authors: Ju L, Zhou C

Abstract
ABSTRACT: Although some patients are initially sensitive to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs), resistance invariably develops. Therefore, it's very important to study the molecular mechanism of this resistance. In our previous study we found that integrin beta1 can induce EGFR TKIs resistance in non-small cell lung cancer (NSCLC) cells. Here we analyzed the association of integrin beta1 and c-MET that is a recognized mechanism of EGFR TKIs resistance in NSCLC to demonstrate the mechanism of integrin beta1 related EGFR TKIs resistance. We found that the ligands of integrin beta1 and c-MET could synergistically promote cell proliferation and their inhibitors could synergistically improve the sensitivity to gfitinib, increase apoptosis, and inhibit the downstream signal transduction: focal adhesion kinase (FAK) and AKT. On the other hand, ligand-dependent activation of integrin beta1 could induce EGFR TKIs resistance through activating c-MET and its downstream signals. Thus, it can be concluded that there is crosstalk between integrin beta1 and c-MET and integrin beta1 mediates EGFR TKI resistance associating with c-MET signaling pathway in non-small cell lung cancer.

PMID: 23402326 [PubMed - as supplied by publisher]

Vasorelaxant and antihypertensive effects of methanolic extracts from Hymenocardia acida Tul.

Vasorelaxant and antihypertensive effects of methanolic extracts from Hymenocardia acida Tul.

J Ethnopharmacol. 2013 Feb 11;

Authors: Nsuadi Manga F, El Khattabi C, Fontaine J, Berkenboom G, Duez P, Noyon C, Van Antwerpen P, Lami Nzunzu J, Pochet S

Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: In Congolese traditional medicine, decoctions of Hymenocardia acida root bark (HaRB) and trunk bark (HaTrB) are used for the treatment of conditions assumed to be hypertension. AIM OF THE STUDY: To study the vasorelaxant effect of HaRB and HaTrB methanolic extracts on isolated rat thoracic aorta, to characterize the group of molecules responsible for the observed vasorelaxant activity, to evaluate the in vitro antioxidant activity of these extracts and to determine the antihypertensive activity of the HaRB extract on spontaneously hypertensive rats (SHR). Materials and methods: The vasorelaxant effect of the HaRB and HaTrB methanolic extracts was studied on endothelium-intact aortic rings pre-contracted with phenylephrine (PE, 1�M). The mechanism of this vasorelaxant effect was investigated on endothelium-denuded vessels and on endothelium-intact aortic rings in the presence of three inhibitors: L-N(G)-nitroarginine methyl ester (100�M), indomethacin (10�M) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (10�M). To determine the nature of the compounds responsible for the vasorelaxant activity, we carried out a fractionation of the extracts and a thiolysis of the most active fraction followed by a liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) analysis. The extracts antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) colorimetric assay. In vivo anti-hypertensive activity of the HaRB extract was conducted on SHR. RESULTS: HaRB and HaTrB methanolic extracts produced a concentration-dependent vasorelaxation on intact aortic rings pre-contracted with PE (1�M). The vasorelaxant responses obtained were 95.3�1.5% (5�g/ml) and 100.6�3.0% (1�g/ml), respectively. The effect was markedly attenuated by removal of endothelium or pretreatment of aortic rings with all inhibitors except indomethacin. The LC/ESI-MS analysis of the thiolysis products indicated that the fraction which caused the most important vasorelaxation (97.9�2.5% at 3�g/ml) was a mixture of procyanidins and prodelphinidins, with a predominance of procyanidins. Both extracts and all fractions from HaRB extract showed a DPPH scavenging activity, ranging from 0.4 to 0.8 quercetin-equivalents The HaRB methanolic extract reduced the systolic blood pressure in SHR (from 214�3mmHg to 194�4mmHg) after a 5-week treatment. CONCLUSIONS: The methanolic extracts of Hymenocardia acida root and trunk bark have vasorelaxant activity. The vasorelaxant effect observed is endothelium-dependent and seems mainly mediated through the NO-cGMP pathway. The COX pathway is not involved. The vasorelaxant activity appears to be due to polymeric procyanidins and prodelphinidins. These extracts also have an antioxidant effect. The extract of Hymenocardia acida root bark shows a significant but weak antihypertensive activity in SHR.

PMID: 23411013 [PubMed - as supplied by publisher]

Combined inhibition of PI3K-related DNA-damage response kinases and mTORC1 induces apoptosis in MYC-driven B-cell lymphomas.

Combined inhibition of PI3K-related DNA-damage response kinases and mTORC1 induces apoptosis in MYC-driven B-cell lymphomas.

Blood. 2013 Feb 12;

Authors: Shortt J, Martin BP, Newbold A, Hannan KM, Devlin JR, Baker AJ, Ralli R, Cullinane C, Schmitt CA, Reimann M, Hall MN, Wall M, Hannan RD, Pearson RB, McArthur GA, Johnstone RW

Abstract
Pharmacological strategies capable of directly targeting MYC are elusive. Previous studies have shown that MYC-driven lymphomagenesis is associated with mammalian target of rapamycin (mTOR) activation and a MYC-evoked DNA damage response (DDR), transduced by phosphatidylinositol-3-kinase (PI3K)-related kinases (DNA-PK, ATM and ATR). Here we report that BEZ235, a multi-targeted pan-PI3K/dual-mTOR inhibitor, potently killed primary Myc-driven B-cell lymphomas and human cell lines bearing IG-cMYC translocations. Using pharmacological and genetic dissection of PI3K/mTOR signaling, dual DDR/mTORC1 inhibition was identified as a key mediator of apoptosis. Moreover, apoptosis was initiated at drug concentrations insufficient to antagonize PI3K/mTORC2-regulated AKT phosphorylation. p53-independent induction of the pro-apoptotic BH3-only protein, BMF, was identified as a mechanism by which dual DDR/mTORC1 inhibition caused lymphoma cell death. BEZ235 treatment induced apoptotic tumor regressions in vivo that correlated with suppression of mTORC1-regulated substrates and reduced H2AX phosphorylation and also with feedback phosphorylation of AKT. These mechanistic studies hold important implications for the use of multi-targeted PI3K inhibitors in the treatment of hematological malignancies. In particular the newly elucidated role of PI3K-related DDR-kinases in the response to PI3K inhibitors offers a novel therapeutic opportunity for the treatment of hematological malignancies with a MYC-driven DDR.

PMID: 23403624 [PubMed - as supplied by publisher]