All-trans retinoic acid synergizes with FLT3 inhibition to eliminate FLT3/ITD+ leukemia stem cells in vitro and in vivo.

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Ma, Hayley S; Greenblatt, Sarah M; Shirley, Courtney M; Duffield, Amy S; Bruner, J Kyle; Li, Li; Nguyen, Bao; Jung, Eric; Aplan, Peter D; Ghiaur, Gabriel; Jones, Richard J; Small, Donald

2016-06-09

FMS-like tyrosine kinase 3 (FLT3)-mutant acute myeloid leukemia (AML) portends a poor prognosis, and ineffective targeting of the leukemic stem cell (LSC) population remains one of several obstacles in treating this disease. All-trans retinoic acid (ATRA) has been used in several clinical trials for the treatment of nonpromyelocytic AML with limited clinical activity observed. FLT3 tyrosine kinase inhibitors (TKIs) used as monotherapy also achieve limited clinical responses and are thus far unable to affect cure rates in AML patients. We explored the efficacy of combining ATRA and FLT3 TKIs to eliminate FLT3/internal tandem duplication (ITD)(+) LSCs. Our studies reveal highly synergistic drug activity, preferentially inducing apoptosis in FLT3/ITD(+) cell lines and patient samples. Colony-forming unit assays further demonstrate decreased clonogenicity of FLT3/ITD(+) cells upon treatment with ATRA and TKI. Most importantly, the drug combination depletes FLT3/ITD(+) LSCs in a genetic mouse model of AML, and prolongs survival of leukemic mice. Furthermore, engraftment of primary FLT3/ITD(+) patient samples is reduced in mice following treatment with FLT3 TKI and ATRA in combination, with evidence of cellular differentiation occurring in vivo. Mechanistically, we provide evidence that the synergism of ATRA and FLT3 TKIs is at least in part due to the observation that FLT3 TKI treatment upregulates the antiapoptotic protein Bcl6, limiting the drug's apoptotic effect. However, cotreatment with ATRA reduces Bcl6 expression to baseline levels through suppression of interleukin-6 receptor signaling. These studies provide evidence of the potential of this drug combination to eliminate FLT3/ITD(+) LSCs and reduce the rate of relapse in AML patients with FLT3 mutations.

Chemical Space of FLT3 Inhibitors as Potential Anti-AML Drugs.

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Lan, Qing-Yuan; Zhi, Yan-Le; Heng, Hao; Tian, Jie-Yi; Guo, Xiao-Xing; Liu, Hai-Chun; Chen, Ya-Dong; Lu, Tao; Lu, Shuai

2017-11-20

FLT3 is a member of receptor tyrosine kinase III family, mainly expressed in hematopoietic cells. The aberrant expression and function of FLT3 are strongly related to leukemia, especially acute myeloid leukemia. Its varieties of amino-acid residues mutations, such as FLT3-ITDs and -TKDs, can induce constant proliferation of hematological tumor cells with poor prognosis. Hence FLT3 serves as a promising target in AML chemotherapy. This review focused on the progress of FLT3 inhibitors study including those that have entered clinical trials or were reported in numerous patents all over the world. Thus, we provided a useful reference for the development of new anti-leukemia drugs. Through a comprehensive retrospective study, FLT3 inhibitors in several patent applications were identified and classified into five categories, including quinolone-related, indole-related, ureas, pyrimidines and other compounds. For each category of compounds, the structural feature, SAR, biological activity and current research status were thoroughly reviewed and analyzed. Although some of those compounds expressed potent bioactivities and have reached the advanced clinical trials for the treatment of leukemia, there are still several problems need to be faced before they enter the market eventually, especially the drug resistance issue. The improvement of therapeutic potency for FLT3 inhibitors might depend on the useful combination therapy and further refinement of the intrinsic properties of FLT3 inhibitors. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Dnmt3a deletion cooperates with the Flt3/ITD mutation to drive leukemogenesis in a murine model

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Poitras, Jennifer L.; Heiser, Diane; Li, Li; Nguyen, Bao; Nagai, Kozo; Duffield, Amy S.; Gamper, Christopher; Small, Donald

2016-01-01

Internal tandem duplications of the juxtamembrane domain of FLT3 (FLT3/ITD) are among the most common mutations in Acute Myeloid Leukemia (AML). Resulting in constitutive activation of the kinase, FLT3/ITD portends a particularly poor prognosis, with reduced overall survival and increased rates of relapse. We previously generated a knock-in mouse, harboring an internal tandem duplication at the endogenous Flt3 locus, which develops a fatal myeloproliferative neoplasm (MPN), but fails to develop acute leukemia, suggesting additional mutations are necessary for transformation. To investigate the potential cooperativity of FLT3/ITD and mutant DNMT3A, we bred a conditional Dnmt3a knockout to a substrain of our Flt3/ITD knock-in mice, and found deletion of Dnmt3a significantly reduced median survival of Flt3ITD/+ mice in a dose dependent manner. As expected, pIpC treated Flt3ITD/+ mice solely developed MPN, while Flt3ITD/+;Dnmt3af/f and Flt3ITD/+;Dnmt3af/+ developed a spectrum of neoplasms, including MPN, T-ALL, and AML. Functionally, FLT3/ITD and DNMT3A deletion cooperate to expand LT-HSCs, which exhibit enhanced self-renewal in serial re-plating assays. These results illustrate that DNMT3A loss cooperates with FLT3/ITD to generate hematopoietic neoplasms, including AML. In combination with FLT3/ITD, homozygous Dnmt3a knock-out results in reduced time to disease onset, LT-HSC expansion, and a higher incidence of T-ALL compared with loss of just one allele. The co-occurrence of FLT3 and DNMT3A mutations in AML, as well as subsets of T-ALL, suggests the Flt3ITD/+;Dnmt3af/f model may serve as a valuable resource for delineating effective therapeutic strategies in two clinically relevant contexts. PMID:27636998

Neurotrophin-3 and FLT3 Tyrosine Kinase Receptor in Perinatal Life

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Ariadne Malamitsi-Puchner

2005-01-01

Full Text Available Our aim is to determine—in 30 healthy full-term infants and their mothers—circulating levels of neurotrophin-3 (NT-3 (important for antenatal and postnatal brain development and implicated in the immune response and FLT3 tyrosine kinase receptor (FLT3 (controlling hematopoiesis and found in the nervous tissue, in the fetal and neonatal life. NT-3 levels, in contrast to FLT3 ones, increased significantly on the fourth postnatal day in relation to the low levels found in the mother, fetus, and day 1 neonate (P=.03, respectively. Maternal and umbilical NT3 levels positively correlated with respective FLT3 levels (P=.003 and P=.03. Circulating NT-3 levels increased in early neonatal life, possibly due to exposure to various stimuli soon after birth. FLT3 levels do not seem to behave accordingly, although these two substances probably synergize.

Breakdown of the FLT3-ITD/STAT5 axis and synergistic apoptosis induction by the histone deacetylase inhibitor panobinostat and FLT3-specific inhibitors.

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Pietschmann, Kristin; Bolck, Hella Anna; Buchwald, Marc; Spielberg, Steffi; Polzer, Harald; Spiekermann, Karsten; Bug, Gesine; Heinzel, Thorsten; Böhmer, Frank-Dietmar; Krämer, Oliver H

2012-11-01

Activating mutations of the class III receptor tyrosine kinase FLT3 are the most frequent molecular aberration in acute myeloid leukemia (AML). Mutant FLT3 accelerates proliferation, suppresses apoptosis, and correlates with poor prognosis. Therefore, it is a promising therapeutic target. Here, we show that RNA interference against FLT3 with an internal tandem duplication (FLT3-ITD) potentiates the efficacy of the histone deacetylase inhibitor (HDACi) panobinostat (LBH589) against AML cells expressing FLT3-ITD. Similar to RNA interference, tyrosine kinase inhibitors (TKI; AC220/cpd.102/PKC412) in combination with LBH589 exhibit superior activity against AML cells. Median dose-effect analyses of drug-induced apoptosis rates of AML cells (MV4-11 and MOLM-13) revealed combination index (CI) values indicating strong synergism. AC220, the most potent and FLT3-specific TKI, shows highest synergism with LBH589 in the low nanomolar range. A 4-hour exposure to LBH589 + AC220 already generates more than 50% apoptosis after 24 hours. Different cell lines lacking FLT3-ITD as well as normal peripheral blood mononuclear cells are not significantly affected by LBH589 + TKI, showing the specificity of this treatment regimen. Immunoblot analyses show that LBH589 + TKI induce apoptosis via degradation of FLT3-ITD and its prosurvival target STAT5. Previously, we showed the LBH589-induced proteasomal degradation of FLT3-ITD. Here, we show that activated caspase-3 also contributes to the degradation of FLT3-ITD and that STAT5 is a direct target of this protease. Our data strongly emphasize HDACi/TKI drug combinations as promising modality for the treatment of FLT3-ITD-positive AMLs. ©2012 AACR.

Targeting FLT3 Signaling in Childhood Acute Myeloid Leukemia

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Amy N. Sexauer

2017-11-01

Full Text Available Acute myeloid leukemia (AML is the second most common leukemia of childhood and is associated with high rates of chemotherapy resistance and relapse. Clinical outcomes for children with AML treated with maximally intensive multi-agent chemotherapy lag far behind those of children with the more common acute lymphoblastic leukemia, demonstrating continued need for new therapeutic approaches to decrease relapse risk and improve long-term survival. Mutations in the FMS-like tyrosine kinase-3 receptor gene (FLT3 occur in approximately 25% of children and adults with AML and are associated with particularly poor prognoses. Identification and development of targeted FLT3 inhibitors represents a major precision medicine paradigm shift in the treatment of patients with AML. While further development of many first-generation FLT3 inhibitors was hampered by limited potency and significant toxicity due to effects upon other kinases, the more selective second- and third-generation FLT3 inhibitors have demonstrated excellent tolerability and remarkable efficacy in the relapsed/refractory and now de novo FLT3-mutated AML settings. While these newest and most promising inhibitors have largely been studied in the adult population, pediatric investigation of FLT3 inhibitors with chemotherapy is relatively recently ongoing or planned. Successful development of FLT3 inhibitor-based therapies will be essential to improve outcomes in children with this high-risk subtype of AML.

Inhibitory effect of turmeric curcuminoids on FLT3 expression and cell cycle arrest in the FLT3-overexpressing EoL-1 leukemic cell line.

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Tima, Singkome; Ichikawa, Hideki; Ampasavate, Chadarat; Okonogi, Siriporn; Anuchapreeda, Songyot

2014-04-25

Leukemia is a hematologic malignancy with a frequent incidence and high mortality rate. Previous studies have shown that the FLT3 gene is overexpressed in leukemic blast cells, especially in acute myeloid leukemia. In this study, a commercially available curcuminoid mixture (1), pure curcumin (2), pure demethoxycurcumin (3), and pure bisdemethoxycurcumin (4) were investigated for their inhibitory effects on cell growth, FLT3 expression, and cell cycle progression in an FLT3-overexpressing EoL-1 leukemic cell line using an MTT assay, Western blotting, and flow cytometry, respectively. The mixture (1) and compounds 2-4 demonstrated cytotoxic effects with IC50 values ranging from 6.5 to 22.5 μM. A significant decrease in FLT3 protein levels was found after curcuminoid treatment with IC20 doses, especially with mixture 1 and compound 2. In addition, mixture 1 and curcumin (2) showed activity on cell cycle arrest at the G0/G1 phase and decreased the FLT3 and STAT5A protein levels in a dose-dependent manner. Compound 2 demonstrated the greatest potential for inhibiting cell growth, cell cycle progression, and FLT3 expression in EoL-1 cells. This investigation has provided new findings regarding the effect of turmeric curcuminoids on FLT3 expression in leukemic cells.

FLT3/ITD associated with an immature immunophenotype in PML-RARα leukemia

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Mariko Takenokuchi

2012-10-01

Full Text Available Acute promyelocytic leukemia (APL is characterized by the specific PML-RARa fusion gene resulting from translocation t(15;17 (q22;q12. Internal tandem duplication (ITD of the FLT3 gene has been observed in approximately 35% of APLs, and large-scale studies have identified the presence of ITD as an adverse prognostic factor for acute myeloblastic leukemia (AML patients. Aberrant expressions of surface antigens, such as CD2, CD34, and CD56, have been found in APL, but the implications of this are not well understood. We investigated the incidence of the FLT3/ITD mutation and FLT3/D835 (I836 point mutation in 25 APL patients. Incidence ratios of FLT3/ITD, D835 (I836, and both FLT3/ITD and D835 (I836 were 36%, 36% and 8%, respectively. FLT3/ITD+ cases showed a predominance of the bcr3 isoform (P=0.008 and M3v morphology (P<0.001. We found that all FLT3/ITD+ cases expressed CD2 (9 of 9 more frequently than that of FLT3/ITD- (1 of 16 (P<0.001, while only one of the CD2+ cases (1 of 10, 10% did not harbor FLT3/ITD, and all CD2+CD34+ cases (5 of 5, 100% harbored FLT3/ITD. In addition, quantitative polymerase chain reaction analysis showed that FLT3 mRNA was more abundantly expressed in FLT3/ITD+ than that in FLT3/ITD- (P=0.025, while there was no difference between D835(I836+ and D835(I836- with regards to aberrant surface-antigen expression, expression levels of FLT3 mRNA, M3v morphology, and the bcr3 isoform of PML-RARa mRNA. This study demonstrates that the presence of FLT3/ITD, but not D835 (I836, is closely related to aberrant CD2 expression and high expression levels of FLT3 mRNA. Our findings also suggest that FLT3/ITD as a secondary genetic event may block differentiation at the immature stage of APL.

Internal Tandem Duplication in FLT3 Attenuates Proliferation and Regulates Resistance to the FLT3 Inhibitor AC220 by Modulating p21Cdkn1a and Pbx1 in Hematopoietic Cells.

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Mariko Abe

Full Text Available Internal tandem duplication (ITD mutations in the Fms-related tyrosine kinase 3 (FLT3 gene (FLT3-ITD are associated with poor prognosis in patients with acute myeloid leukemia (AML. Due to the development of drug resistance, few FLT3-ITD inhibitors are effective against FLT3-ITD+ AML. In this study, we show that FLT3-ITD activates a novel pathway involving p21Cdkn1a (p21 and pre-B cell leukemia transcription factor 1 (Pbx1 that attenuates FLT3-ITD cell proliferation and is involved in the development of drug resistance. FLT3-ITD up-regulated p21 expression in both mouse bone marrow c-kit+-Sca-1+-Lin- (KSL cells and Ba/F3 cells. The loss of p21 expression enhanced growth factor-independent proliferation and sensitivity to cytarabine as a consequence of concomitantly enriching the S+G2/M phase population and significantly increasing the expression of Pbx1, but not Evi-1, in FLT3-ITD+ cells. This enhanced cell proliferation following the loss of p21 was partially abrogated when Pbx1 expression was silenced in FLT3-ITD+ primary bone marrow colony-forming cells and Ba/F3 cells. When FLT3-ITD was antagonized with AC220, a selective inhibitor of FLT3-ITD, p21 expression was decreased coincident with Pbx1 mRNA up-regulation and a rapid decline in the number of viable FLT3-ITD+ Ba/F3 cells; however, the cells eventually became refractory to AC220. Overexpressing p21 in FLT3-ITD+ Ba/F3 cells delayed the emergence of cells that were refractory to AC220, whereas p21 silencing accelerated their development. These data indicate that FLT3-ITD is capable of inhibiting FLT3-ITD+ cell proliferation through the p21/Pbx1 axis and that treatments that antagonize FLT3-ITD contribute to the subsequent development of cells that are refractory to a FLT3-ITD inhibitor by disrupting p21 expression.

Targeting oncoprotein stability overcomes drug resistance caused by FLT3 kinase domain mutations.

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Chuanjiang Yu

Full Text Available FLT3 is the most frequently mutated kinase in acute myeloid leukemia (AML. Internal tandem duplications (ITDs in the juxta-membrane region constitute the majority of activating FLT3 mutations. Several FLT3 kinase inhibitors were developed and tested in the clinic with significant success. However, recent studies have reported the development of secondary drug resistance in patients treated with FLT3 inhibitors. Since FLT3-ITD is an HSP90 client kinase, we here explored if targeting the stability of drug-resistant FLT3 mutant protein could be a potential therapeutic option. We observed that HSP90 inhibitor treatment resulted in the degradation of inhibitor-resistant FLT3-ITD mutants and selectively induced toxicity in cells expressing FLT3-ITD mutants. Thus, HSP90 inhibitors provide a potential therapeutic choice to overcome secondary drug resistance following TKI treatment in FLT3-ITD positive AML.

Frequency and Prognostic Relevance of FLT3 Mutations in Saudi Acute Myeloid Leukemia Patients

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Ghaleb Elyamany

2014-01-01

Full Text Available The Fms-like tyrosine kinase-3 (FLT3 is a receptor tyrosine kinase that plays a key role in cell survival, proliferation, and differentiation of hematopoietic stem cells. Mutations of FLT3 were first described in 1997 and account for the most frequent molecular mutations in acute myeloid leukemia (AML. AML patients with FLT3 internal tandem duplication (ITD mutations have poor cure rates the prognostic significance of point mutations; tyrosine kinase domain (TKD is still unclear. We analyzed the frequency of FLT3 mutations (ITD and D835 in patients with AML at diagnosis; no sufficient data currently exist regarding FLT3 mutations in Saudi AML patients. This study was aimed at evaluating the frequency of FLT3 mutations in patients with AML and its significance for prognosis. The frequency of FLT3 mutations in our study (18.56% was lower than many of the reported studies, FLT3-ITD mutations were observed in 14.4%, and FLT3-TKD in 4.1%, of 97 newly diagnosed AML patients (82 adult and 15 pediatric. Our data show significant increase of FLT3 mutations in male more than female (13 male, 5 female. Our results support the view that FLT3-ITD mutation has strong prognostic factor in AML patients and is associated with high rate of relapse, and high leucocytes and blast count at diagnosis and relapse.

Human Flt3L generates dendritic cells from canine peripheral blood precursors: implications for a dog glioma clinical trial.

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Weidong Xiong

2010-06-01

Full Text Available Glioblastoma multiforme (GBM is the most common primary brain tumor in adults and carries a dismal prognosis. We have developed a conditional cytotoxic/immunotherapeutic approach using adenoviral vectors (Ads encoding the immunostimulatory cytokine, human soluble fms-like tyrosine kinase 3 ligand (hsFlt3L and the conditional cytotoxic molecule, i.e., Herpes Simplex Type 1- thymide kinase (TK. This therapy triggers an anti-tumor immune response that leads to tumor regression and anti-tumor immunological memory in intracranial rodent cancer models. We aim to test the efficacy of this immunotherapy in dogs bearing spontaneous GBM. In view of the controversy regarding the effect of human cytokines on dog immune cells, and considering that the efficacy of this treatment depends on hsFlt3L-stimulated dendritic cells (DCs, in the present work we tested the ability of Ad-encoded hsFlt3L to generate DCs from dog peripheral blood and compared its effects with canine IL-4 and GM-CSF.Our results demonstrate that hsFlT3L expressed form an Ad vector, generated DCs from peripheral blood cultures with very similar morphological and phenotypic characteristics to canine IL-4 and GM-CSF-cultured DCs. These include phagocytic activity and expression of CD11c, MHCII, CD80 and CD14. Maturation of DCs cultured under both conditions resulted in increased secretion of IL-6, TNF-alpha and IFN-gamma. Importantly, hsFlt3L-derived antigen presenting cells showed allostimulatory potential highlighting their ability to present antigen to T cells and elicit their proliferation.These results demonstrate that hsFlt3L induces the proliferation of canine DCs and support its use in upcoming clinical trials for canine GBM. Our data further support the translation of hsFlt3L to be used for dendritic cells' vaccination and gene therapeutic approaches from rodent models to canine patients and its future implementation in human clinical trials.

Ligand-receptor assay for evaluation of functional activity of human recombinant VEGF and VEGFR-1 extracellular fragment.

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Leopol'd, A V; Baklaushev, V P; Korchagina, A A; Shein, S A; Grinenko, N F; Pavlov, K A; Ryabukhin, I A; Chekhonin, V P

2012-04-01

cDNA encoding VEGF and Ig-like extracellular domains 2-4 of VEGFR-1 (sFlt-1(2-4)) were cloned into prokaryotic expression vectors pET32a and pQE60. Recombinant proteins were purified (metal affinity chromatography) and renatured. Chemiluminescent study for the interaction of recombinant VEGF and sFlt-1(2-4) showed that biotinylated VEGF specifically binds to the polystyrene-immobilized receptor extracellular fragment. Biotinylated recombinant sFlt-1 interacts with immobilized VEGF. Analysis of the interaction of immobilized recombinant VEGFR-1 and VEGF with C6 glioma cells labeled with CFDA-SE (vital fluorescent dye) showed that recombinant VEGFR-1 also binds to native membrane-associated VEGF. Recombinant VEGF was shown to bind to specific receptors expressed on the surface of C6 glioma cells. Functional activity of these proteins was confirmed by ligand-receptor assay for VEGF and VEGFR-1 (sFlt-1) and quantitative chemiluminescent detection.

Niche-mediated depletion of the normal hematopoietic stem cell reservoir by Flt3-ITD–induced myeloproliferation

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Matsuoka, Sahoko; Thongjuea, Supat; Jamieson, Lauren; Atkinson, Deborah; Kharazi, Shabnam; Suda, Toshio

2017-01-01

Although previous studies suggested that the expression of FMS-like tyrosine kinase 3 (Flt3) initiates downstream of mouse hematopoietic stem cells (HSCs), FLT3 internal tandem duplications (FLT3 ITDs) have recently been suggested to intrinsically suppress HSCs. Herein, single-cell interrogation found Flt3 mRNA expression to be absent in the large majority of phenotypic HSCs, with a strong negative correlation between Flt3 and HSC-associated gene expression. Flt3-ITD knock-in mice showed reduced numbers of phenotypic HSCs, with an even more severe loss of long-term repopulating HSCs, likely reflecting the presence of non-HSCs within the phenotypic HSC compartment. Competitive transplantation experiments established that Flt3-ITD compromises HSCs through an extrinsically mediated mechanism of disrupting HSC-supporting bone marrow stromal cells, with reduced numbers of endothelial and mesenchymal stromal cells showing increased inflammation-associated gene expression. Tumor necrosis factor (TNF), a cell-extrinsic potent negative regulator of HSCs, was overexpressed in bone marrow niche cells from FLT3-ITD mice, and anti-TNF treatment partially rescued the HSC phenotype. These findings, which establish that Flt3-ITD–driven myeloproliferation results in cell-extrinsic suppression of the normal HSC reservoir, are of relevance for several aspects of acute myeloid leukemia biology. PMID:28637883

FLT3 mutation incidence and timing of origin in a population case series of pediatric leukemia

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Chang Jeffrey

2010-09-01

Full Text Available Abstract Background Mutations in FLT3 result in activated tyrosine kinase activity, cell growth stimulation, and a poor prognosis among various subtypes of leukemia. The causes and timing of the mutations are not currently known. We evaluated the prevalence and timing of origin of FLT3 mutations in a population series of childhood leukemia patients from Northern California. Methods We screened and sequenced FLT3 mutations (point mutations and internal tandem duplications, ITDs among 517 childhood leukemia patients, and assessed whether these mutations occurred before or after birth using sensitive "backtracking" methods. Results We determined a mutation prevalence of 9 of 73 acute myeloid leukemias (AMLs, 12% and 9 of 441 acute lymphocytic leukemias (ALLs, 2%. Among AMLs, FLT3 mutations were more common in older patients, and among ALLs, FLT3 mutations were more common in patients with high hyperdiploidy (3.7% than those without this cytogenetic feature (1.4%. Five FLT3 ITDs, one deletion mutation, and 3 point mutations were assessed for their presence in neonatal Guthrie spots using sensitive real-time PCR techniques, and no patients were found to harbor FLT3 mutations at birth. Conclusions FLT3 mutations were not common in our population-based patient series in California, and patients who harbor FLT3 mutations most likely acquire them after they are born.

Inhibition of MEK5 by BIX02188 induces apoptosis in cells expressing the oncogenic mutant FLT3-ITD

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Razumovskaya, Elena; Sun, Jianmin; Roennstrand, Lars

2011-01-01

Highlights: → In this study we have demonstrated that FLT3 activation leads to activation of ERK5. → We have demonstrated that ERK5 is involved in activation of AKT downstream of FLT3. → (BIX02188) blocks activation of ERK5 and induces apoptosis in FLT3 Ba/F3 cells. → (BIX02188) induce apoptosis in the two leukemic cell lines MV4-11 and MOLM-13. -- Abstract: Fms-like tyrosine kinase-3 (FLT3) is a growth factor receptor normally expressed on hematopoietic progenitor cells. Approximately one third of all patients with AML carry an activating mutation in FLT3 that drives proliferation and survival of the leukemic cells. The most common activating mutation is the so-called internal tandem duplication (ITD), which involves an in-frame duplication of a segment of varying length in the region of the FLT3 gene that encodes the juxtamembrane domain. The pathways downstream of FLT3-ITD are partially known but further knowledge regarding the downstream signal transduction molecules is important in order to develop alternative strategies for pharmacological intervention. In this paper we have studied the role of MEK/ERK5 in FLT3-ITD mediated transformation. We have found that both wild-type FLT3 and FLT3-ITD activate MEK5 leading to the activation of ERK5. By use of the selective inhibitor of MEK5, (BIX02188), we have shown that activation of AKT downstream of FLT3 is partially dependent on ERK5. Furthermore, inhibition of MEK5/ERK5 induces apoptosis of both FLT3-ITD transfected Ba/F3 cells as well as the FLT3-ITD carrying leukemic cell lines MV4-11 and MOLM-13. These results suggest that MEK5/ERK5 is important for FLT3-ITD induced hematopoietic transformation and may thus represent an alternative therapeutic target in the treatment of FLT3-ITD positive leukemia.

Tyrosine 842 in the activation loop is required for full transformation by the oncogenic mutant FLT3-ITD.

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Kazi, Julhash U; Chougule, Rohit A; Li, Tianfeng; Su, Xianwei; Moharram, Sausan A; Rupar, Kaja; Marhäll, Alissa; Gazi, Mohiuddin; Sun, Jianmin; Zhao, Hui; Rönnstrand, Lars

2017-07-01

The type III receptor tyrosine kinase FLT3 is frequently mutated in acute myeloid leukemia. Oncogenic FLT3 mutants display constitutive activity leading to aberrant cell proliferation and survival. Phosphorylation on several critical tyrosine residues is known to be essential for FLT3 signaling. Among these tyrosine residues, Y842 is located in the so-called activation loop. The position of this tyrosine residue is well conserved in all receptor tyrosine kinases. It has been reported that phosphorylation of the activation loop tyrosine is critical for catalytic activity for some but not all receptor tyrosine kinases. The role of Y842 residue in FLT3 signaling has not yet been studied. In this report, we show that Y842 is not important for FLT3 activation or ubiquitination but plays a critical role in regulating signaling downstream of the receptor as well as controlling receptor stability. We found that mutation of Y842 in the FLT3-ITD oncogenic mutant background reduced cell viability and increased apoptosis. Furthermore, the introduction of the Y842 mutation in the FLT3-ITD background led to a dramatic reduction in in vitro colony forming capacity. Additionally, mice injected with cells expressing FLT3-ITD/Y842F displayed a significant delay in tumor formation, compared to FLT3-ITD expressing cells. Microarray analysis comparing gene expression regulated by FLT3-ITD versus FLT3-ITD/Y842F demonstrated that mutation of Y842 causes suppression of anti-apoptotic genes. Furthermore, we showed that cells expressing FLT3-ITD/Y842F display impaired activity of the RAS/ERK pathway due to reduced interaction between FLT3 and SHP2 leading to reduced SHP2 activation. Thus, we suggest that Y842 is critical for FLT3-mediated RAS/ERK signaling and cellular transformation.

The Important Role of FLT3-L in Ex Vivo Expansion of Hematopoietic Stem Cells following Co-Culture with Mesenchymal Stem Cells.

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Oubari, Farhad; Amirizade, Naser; Mohammadpour, Hemn; Nakhlestani, Mozhdeh; Zarif, Mahin Nikougoftar

2015-01-01

Hematopoietic stem cells (HSCs) transplantation using umbilical cord blood (UCB) has improved during the last decade. Because of cell limitations, several studies focused on the ex vivo expansion of HSCs. Numerous investigations were performed to introduce the best cytokine cocktails for HSC expansion The majority used the Fms-related tyrosine kinase 3 ligand (FLT3-L) as a critical component. According to FLT3-L biology, in this study we have investigated the hypothesis that FLT3-L only effectively induces HSCs expansion in the presence of a mesenchymal stem cell (MSC) feeder. In this experimental study, HSCs and MSCs were isolated from UCB and placenta, respectively. HSCs were cultured in different culture conditions in the presence and absence of MSC feeder and cytokines. After ten days of culture, total nucleated cell count (TNC), cluster of differentiation 34+(CD34(+)) cell count, colony forming unit assay (CFU), long-term culture initiating cell (LTC-IC), homeobox protein B4 (HoxB4) mRNA and surface CD49d expression were evaluated. The fold increase for some culture conditions was compared by the t test. HSCs expanded in the presence of cytokines and MSCs feeder. The rate of expansion in the co-culture condition was two-fold more than culture with cytokines (Pculture condition at a level of 20-fold equal to the presence of stem cell factor (SCF), thrombopoietin (TPO) and FLT3-L without feeder cells. The number of extracted colonies from LTC-IC and CD49d expression compared with a cytokine cocktail condition meaningfully increased (Pculture with MSCs can induce high yield expansion of HSCs and be a substitute for the universal cocktail of SCF, TPO and FLT3-L in feeder-free culture.

Flt3L controls the development of radiosensitive dendritic cells in the meninges and choroid plexus of the steady-state mouse brain.

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Anandasabapathy, Niroshana; Victora, Gabriel D; Meredith, Matthew; Feder, Rachel; Dong, Baojun; Kluger, Courtney; Yao, Kaihui; Dustin, Michael L; Nussenzweig, Michel C; Steinman, Ralph M; Liu, Kang

2011-08-01

Antigen-presenting cells in the disease-free brain have been identified primarily by expression of antigens such as CD11b, CD11c, and MHC II, which can be shared by dendritic cells (DCs), microglia, and monocytes. In this study, starting with the criterion of Flt3 (FMS-like receptor tyrosine kinase 3)-dependent development, we characterize the features of authentic DCs within the meninges and choroid plexus in healthy mouse brains. Analyses of morphology, gene expression, and antigen-presenting function established a close relationship between meningeal and choroid plexus DCs (m/chDCs) and spleen DCs. DCs in both sites shared an intrinsic requirement for Flt3 ligand. Microarrays revealed differences in expression of transcripts encoding surface molecules, transcription factors, pattern recognition receptors, and other genes in m/chDCs compared with monocytes and microglia. Migrating pre-DC progenitors from bone marrow gave rise to m/chDCs that had a 5-7-d half-life. In contrast to microglia, DCs actively present self-antigens and stimulate T cells. Therefore, the meninges and choroid plexus of a steady-state brain contain DCs that derive from local precursors and exhibit a differentiation and antigen-presenting program similar to spleen DCs and distinct from microglia.

Temporal Changes in FLT3 ITD Regulation of Stem Cell Self Renewal and Leukemogenesis

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2016-11-01

AML) more frequently in adults than in children. FLT3-ITD encodes a constitutively active FLT3 tyrosine kinase. This mutation occurs in ~30% of adult...2006). FLT3ITD encodes a constitutively active tyrosine kinase 87   receptor that has been shown to activate the STAT5, MAP-kinase (MAPK), PI3-88...define cell populations: HSCs (CD150+, CD48-Lineage-, Sca1+, c-kit+), HPCs 570   (CD48-Lineage-, Sca1+, c-kit+), and GMPs (Lineage-, Sca1-, CD127-, c

Preliminary 19F-MRS Study of Tumor Cell Proliferation with 3′-deoxy-3′-fluorothymidine and Its Metabolite (FLT-MP

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In Ok Ko

2017-01-01

Full Text Available The thymidine analogue 3′-deoxy-3′-[18F]fluorothymidine, or [18F]fluorothymidine ([18F]FLT, is used to measure tumor cell proliferation with positron emission tomography (PET imaging technology in nuclear medicine. FLT is phosphorylated by thymidine kinase 1 (TK1 and then trapped inside cells; it is not incorporated into DNA. Imaging with 18F-radiolabeled FLT is a noninvasive technique to visualize cellular proliferation in tumors. However, it is difficult to distinguish between [18F]FLT and its metabolites by PET imaging, and quantification has not been attempted using current imaging methods. In this study, we successfully acquired in vivo F19 spectra of natural or nonradioactive 3′-deoxy-3′-fluorothymidine ([19F]FLT and its monophosphate metabolite (FLT-MP in a tumor xenograft mouse model using 9.4T magnetic resonance imaging (MRI. This preliminary result demonstrates that 19F magnetic resonance spectroscopy (MRS with FLT is suitable for the in vivo assessment of tumor aggressiveness and for early prediction of treatment response.

Characterisation and Clinical Significance of FLT3-ITD and non-ITD in Acute Myeloid Leukaemia Patients in Kelantan, Northeast Peninsular Malaysia.

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Yunus, Noraini Mat; Johan, Muhammad Farid; Ali Nagi Al-Jamal, Hamid; Husin, Azlan; Hussein, Abdul Rahim; Hassan, Rosline

2015-01-01

Mutations of the FMS-like tyrosine kinase-3 (FLT3) receptor gene may promote proliferation via activation of multiple signaling pathways. FLT3-internal tandem duplication (FLT3-ITD) is the most common gene alteration found in patients diagnosed with acute myeloid leukaemia (AML) and has been associated with poor prognosis. We performed mutational analysis of exons 14-15 and 20 of the FLT3 gene in 54 AML patients using PCR-CSGE (conformational sensitive gel electrophoresis) followed by sequencing analysis to characterise FLT3 mutations in adult patients diagnosed with AML at Hospital USM, Kelantan, Northeast Peninsular Malaysia. FLT3 exon 14-15 mutations were identified in 7 of 54 patients (13%) whereas no mutation was found in FLT3 exon 20. Six ITDs and one non-ITD mutation were found in exon 14 of the juxtamembrane (JM) domain of FLT3. FLT3-ITD mutations were associated with a significantly higher blast percentage (p-value=0.008) and white blood cell count (p-value=0.023) but there was no significant difference in median overall survival time for FLT3-ITD+/FLT3-ITD- within 2 years (p-value=0.374). The incidence of FLT3-ITD in AML patients in this particular region of Malaysia is low compared to the Western world and has a significant association with WBC and blast percentage.

The juxtamembrane domain in ETV6/FLT3 is critical for PIM-1 up-regulation and cell proliferation

International Nuclear Information System (INIS)

Vu, Hoang Anh; Xinh, Phan Thi; Kano, Yasuhiko; Tokunaga, Katsushi; Sato, Yuko

2009-01-01

We recently reported that the ETV6/FLT3 fusion protein conferred interleukin-3-independent growth on Ba/F3 cells. The present study has been conducted to assess role of the juxtamembrane domain of FLT3 for signal transduction and cell transformation. The wild-type ETV6/FLT3 fusion protein in transfected cells was a constitutively activated tyrosine kinase that led to up-regulation of PIM-1 and activations of STAT5, AKT, and MAPK. Deletion of the juxtamembrane domain abrogated interleukin-3-independent growth of the transfected cells and PIM-1 up-regulation, whereas it retained compatible levels of phosphorylations of STAT5, AKT, and MAPK. Further deletion of N-terminal region of the tyrosine kinase I domain of FLT3 completely abolished these phosphorylations. Our data indicate that the juxtamembrane domain of FLT3 in ETV6/FLT3 fusion protein is critical for cell proliferation and PIM-1 up-regulation that might be independent of a requirement for signaling through STAT5, MAPK, and AKT pathways.

Soluble Flt-1 links microvascular disease with heart failure in CKD.

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Di Marco, Giovana S; Kentrup, Dominik; Reuter, Stefan; Mayer, Anna B; Golle, Lina; Tiemann, Klaus; Fobker, Manfred; Engelbertz, Christiane; Breithardt, Günter; Brand, Eva; Reinecke, Holger; Pavenstädt, Hermann; Brand, Marcus

2015-05-01

Chronic kidney disease (CKD) is associated with an increased risk of heart failure (HF). Elevated plasma concentrations of soluble Flt-1 (sFlt-1) have been linked to cardiovascular disease in CKD patients, but whether sFlt-1 contributes to HF in CKD is still unknown. To provide evidence that concludes a pathophysiological role of sFlt-1 in CKD-associated HF, we measured plasma sFlt-1 concentrations in 586 patients with angiographically documented coronary artery disease and renal function classified according to estimated glomerular filtration rate (eGFR). sFlt-1 concentrations correlated negatively with eGFR and were associated with signs of heart failure, based on New York Heart Association functional class and reduced left ventricular ejection fraction (LVEF), and early mortality. Additionally, rats treated with recombinant sFlt-1 showed a 15 % reduction in LVEF and a 29 % reduction in cardiac output compared with control rats. High sFlt-1 concentrations were associated with a 15 % reduction in heart capillary density (number of vessels/cardiomyocyte) and a 24 % reduction in myocardial blood volume. Electron microscopy and histological analysis revealed mitochondrial damage and interstitial fibrosis in the hearts of sFlt-1-treated, but not control rats. In 5/6-nephrectomised rats, an animal model of CKD, sFlt-1 antagonism with recombinant VEGF121 preserved heart microvasculature and significantly improved heart function. Overall, these findings suggest that a component of cardiovascular risk in CKD patients could be directly attributed to sFlt-1. Assessment of patients with CKD confirmed that sFlt-1 concentrations were inversely correlated with renal function, while studies in rats suggested that sFlt-1 may link microvascular disease with HF in CKD.

A noncanonical Flt3ITD/NF-κB signaling pathway represses DAPK1 in acute myeloid leukemia.

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Shanmugam, Rajasubramaniam; Gade, Padmaja; Wilson-Weekes, Annique; Sayar, Hamid; Suvannasankha, Attaya; Goswami, Chirayu; Li, Lang; Gupta, Sushil; Cardoso, Angelo A; Baghdadi, Tareq Al; Sargent, Katie J; Cripe, Larry D; Kalvakolanu, Dhananjaya V; Boswell, H Scott

2012-01-15

Death-associated protein kinase 1 (DAPK1), a tumor suppressor, is a rate-limiting effector in an endoplasmic reticulum (ER) stress-dependent apoptotic pathway. Its expression is epigenetically suppressed in several tumors. A mechanistic basis for epigenetic/transcriptional repression of DAPK1 was investigated in certain forms of acute myeloid leukemia (AML) with poor prognosis, which lacked ER stress-induced apoptosis. Heterogeneous primary AMLs were screened to identify a subgroup with Flt3ITD in which repression of DAPK1, among NF-κB-and c-Jun-responsive genes, was studied. RNA interference knockdown studies were carried out in an Flt3ITD(+) cell line, MV-4-11, to establish genetic epistasis in the pathway Flt3ITD-TAK1-DAPK1 repression, and chromatin immunoprecipitations were carried out to identify proximate effector proteins, including TAK1-activated p52NF-κB, at the DAPK1 locus. AMLs characterized by normal karyotype with Flt3ITD were found to have 10- to 100-fold lower DAPK1 transcripts normalized to the expression of c-Jun, a transcriptional activator of DAPK1, as compared with a heterogeneous cytogenetic category. In addition, Meis1, a c-Jun-responsive adverse AML prognostic gene signature was measured as control. These Flt3ITD(+) AMLs overexpress relB, a transcriptional repressor, which forms active heterodimers with p52NF-κB. Chromatin immunoprecipitation assays identified p52NF-κB binding to the DAPK1 promoter together with histone deacetylase 2 (HDAC2) and HDAC6 in the Flt3ITD(+) human AML cell line MV-4-11. Knockdown of p52NF-κB or its upstream regulator, NF-κB-inducing kinase (NIK), de-repressed DAPK1. DAPK1-repressed primary Flt3ITD(+) AMLs had selective nuclear activation of p52NF-κB. Flt3ITD promotes a noncanonical pathway via TAK1 and p52NF-κB to suppress DAPK1 in association with HDACs, which explains DAPK1 repression in Flt3ITD(+) AML. ©2011 AACR.

Targeted Therapy of FLT3 in Treatment of AML—Current Status and Future Directions

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Caroline Benedicte Nitter Engen

2014-12-01

Full Text Available Internal tandem duplications (ITDs of the gene encoding the Fms-Like Tyrosine kinase-3 (FLT3 receptor are present in approximately 25% of patients with acute myeloid leukemia (AML. The mutation is associated with poor prognosis, and the aberrant protein product has been hypothesized as an attractive therapeutic target. Various tyrosine kinase inhibitors (TKIs have been developed targeting FLT3, but in spite of initial optimism the first generation TKIs tested in clinical studies generally induce only partial and transient hematological responses. The limited treatment efficacy generally observed may be explained by numerous factors; extensively pretreated and high risk cohorts, suboptimal pharmacodynamic and pharmacokinetic properties of the compounds, acquired TKI resistance, or the possible fact that inhibition of mutated FLT3 alone is not sufficient to avoid disease progression. The second-generation agent quizartinb is showing promising outcomes and seems better tolerated and with less toxic effects than traditional chemotherapeutic agents. Therefore, new generations of TKIs might be feasible for use in combination therapy or in a salvage setting in selected patients. Here, we sum up experiences so far, and we discuss the future outlook of targeting dysregulated FLT3 signaling in the treatment of AML.

Clonal evolution of AML on novel FMS-like tyrosine kinase-3 (FLT3 inhibitor therapy with evolving actionable targets

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Pashtoon M. Kasi

2016-01-01

Full Text Available For acute myeloid leukemia (AML, identification of activating mutations in the FMS-like tyrosine kinase-3 (FLT3 has led to the development of several FLT3-inhibitors. Here we present clinical and next generation sequencing data at the time of progression of a patient on a novel FLT3-inhibitor clinical trial (ASP2215 to show that employing therapeutic interventions with these novel targeted therapies can lead to consequences secondary to selective pressure and clonal evolution of cancer. We describe novel findings alongside data on treatment directed towards actionable aberrations acquired during the process. (Clinical Trial: NCT02014558; registered at: 〈https://clinicaltrials.gov/ct2/show/NCT02014558〉

Potent Activity of Ponatinib (AP24534) in Models of FLT3-Driven Acute Myeloid Leukemia and Other Hematologic Malignancies

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Gozgit, Joseph M.; Wong, Matthew J.; Wardwell, Scott; Tyner, Jeffrey W.; Loriaux, Marc M.; Mohemmad, Qurish K.; Narasimhan, Narayana I.; Shakespeare, William C.; Wang, Frank; Druker, Brian J.; Clackson, Tim; Rivera, Victor M.

2011-01-01

Ponatinib (AP24534) is a novel multitargeted kinase inhibitor that potently inhibits native and mutant BCR-ABL at clinically achievable drug levels. Ponatinib also has in vitro inhibitory activity against a discrete set of kinases implicated in the pathogenesis of other hematologic malignancies, including FLT3, KIT, fibroblast growth factor receptor 1 (FGFR1), and platelet derived growth factor receptor α (PDGFRα). Here, using leukemic cell lines containing activated forms of each of these receptors, we show that ponatinib potently inhibits receptor phosphorylation and cellular proliferation with IC50 values comparable to those required for inhibition of BCR-ABL (0.3 to 20 nmol/L). The activity of ponatinib against the FLT3-ITD mutant, found in up to 30% of acute myeloid leukemia (AML) patients, was particularly notable. In MV4-11 (FLT3-ITD+/+) but not RS4;11 (FLT3-ITD−/−) AML cells, ponatinib inhibited FLT3 signaling and induced apoptosis at concentrations of less than 10 nmol/L. In an MV4-11 mouse xenograft model, once daily oral dosing of ponatinib led to a dose-dependent inhibition of signaling and tumor regression. Ponatinib inhibited viability of primary leukemic blasts from a FLT3-ITD positive AML patient (IC50 4 nmol/L) but not those isolated from 3 patients with AML expressing native FLT3. Overall, these results support the investigation of ponatinib in patients with FLT3-ITD–driven AML and other hematologic malignancies driven by KIT, FGFR1, or PDGFRα. PMID:21482694

A non-canonical Flt3ITD/NF-κB signaling pathway represses DAPK1 in acute myeloid leukemia (AML)

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Shanmugam, Rajasubramaniam; Sayar, Hamid; Suvannasankha, Attaya; Goswami, Chirayu; Li, Lang; Gupta, Sushil; Cardoso, Angelo A.; Baghdadi, Tareq Al; Sargent, Katie J.; Cripe, Larry D.; Kalvakolanu, Dhananjaya V.; Boswell, H. Scott

2014-01-01

Purpose DAPK1, a tumor suppressor, is a rate-limiting effector in an ER stress-dependent apoptotic pathway. Its expression is epigenetically suppressed in several tumors. A mechanistic basis for epigenetic/transcriptional repression of DAPK1 was investigated in certain forms of AML with poor prognosis, which lacked ER stress-induced apoptosis. Experimental Design Heterogeneous primary AMLs were screened to identify a subgroup with Flt3ITD in which repression of DAPK1, among NF-κB- and c- jun-responsive genes, was studied. RNAi knockdown studies were performed in Flt3ITD+ve cell line, MV-4-11, to establish genetic epistasis in the pathway Flt3ITD-TAK1-DAPK1 repression, and chromatin immunoprecipitations were performed to identify proximate effector proteins, including TAK1-activated p52NF-κB, at the DAPK1 locus. Results AMLs characterized by normal karyotype with Flt3ITD were found to have 10-100-fold lower DAPK1 transcripts normalized to the expression of c-jun, a transcriptional activator of DAPK1, as compared to a heterogeneous cytogenetic category. Meis1, a c-jun-responsive adverse AML prognostic gene signature was also measured as control. These Flt3ITD+ve AMLs over-express relB, a transcriptional repressor, which forms active heterodimers with p52NF-κB. Chromatin immunoprecipitation assays identified p52NF-κB binding to the DAPK1 promoter along with HDAC2 and HDAC6 in the Flt3ITD+ve human AML cell line MV-4-11. Knockdown of p52NF-κB or its upstream regulator, NIK, de-repressed DAPK1. DAPK1-repressed primary Flt3ITD+ve AMLs had selective nuclear activation of p52NF-κB. Conclusions Flt3ITD promotes a non-canonical pathway via TAK1 and p52NF-κB to suppress DAPK1 in association with HDACs, which explains DAPK1 repression in Flt3ITD+ve AML. PMID:22096027

Consecutive epigenetically-active agent combinations act in ID1-RUNX3-TET2 and HOXA pathways for Flt3ITD+ve AML.

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Sayar, Hamid; Liu, Yan; Gao, Rui; Zaid, Mohammad Abu; Cripe, Larry D; Weisenbach, Jill; Sargent, Katie J; Nassiri, Mehdi; Li, Lang; Konig, Heiko; Suvannasankha, Attaya; Pan, Feng; Shanmugam, Rajasubramaniam; Goswami, Chirayu; Kapur, Reuben; Xu, Mingjiang; Boswell, H Scott

2018-01-19

Co-occurrence of Flt3ITD and TET2 mutations provoke an animal model of AML by epigenetic repression of Wnt pathway antagonists, including RUNX3, and by hyperexpression of ID1, encoding Wnt agonist. These affect HOXA over-expression and treatment resistance. A comparable epigenetic phenotype was identified among adult AML patients needing novel intervention. We chose combinations of targeted agents acting on distinct effectors, at the levels of both signal transduction and chromatin remodeling, in relapsed/refractory AML's, including Flt3ITD+ve, described with a signature of repressed tumor suppressor genes, involving Wnt antagonist RUNX3 , occurring along with ID1 and HOXA over-expressions. We tracked patient response to combination of Flt3/Raf inhibitor, Sorafenib, and Vorinostat, pan-histone deacetylase inhibitor, without or with added Bortezomib, in consecutive phase I trials. A striking association of rapid objective remissions (near-complete, complete responses) was noted to accompany induced early pharmacodynamic changes within patient blasts in situ, involving these effectors, significantly linking RUNX3 /Wnt antagonist de-repression (80%) and ID1 downregulation (85%), to a response, also preceded by profound HOXA9 repression. Response occurred in context of concurrent TET2 mutation/hypomorphy and Flt3ITD+ve mutation (83% of complete responses). Addition of Bortezomib to the combination was vital to attainment of complete response in Flt3ITD+ve cases exhibiting such Wnt pathway dysregulation.

FLT3 and JAK2 Mutations in Acute Myeloid Leukemia Promote Interchromosomal Homologous Recombination and the Potential for Copy Neutral Loss of Heterozygosity.

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Gaymes, Terry J; Mohamedali, Azim; Eiliazadeh, Anthony L; Darling, David; Mufti, Ghulam J

2017-04-01

Acquired copy neutral LOH (CN-LOH) is a frequent occurrence in myeloid malignancies and is often associated with resistance to standard therapeutic modalities and poor survival. Here, we show that constitutive signaling driven by mutated FLT3 and JAK2 confers interchromosomal homologous recombination (iHR), a precedent for CN-LOH. Using a targeted recombination assay, we determined significant iHR activity in internal tandem duplication FLT3 (FLT3-ITD) and JAK2V617F-mutated cells. Sister chromatid exchanges, a surrogate measure of iHR, was significantly elevated in primary FLT3-ITD normal karyotype acute myeloid leukemia (NK-AML) compared with wild-type FLT3 NK-AML. HR was harmonized to S phase of the cell cycle to repair broken chromatids and prevent iHR. Increased HR activity in G 0 arrested primary FLT3-ITD NK-AML in contrast to wild-type FLT3 NK-AML. Cells expressing mutated FLT3-ITD demonstrated a relative increase in mutation frequency as detected by thymidine kinase (TK) gene mutation assay. Moreover, resistance was associated with CN-LOH at the TK locus. Treatment of FLT3-ITD- and JAK2V617F-mutant cells with the antioxidant N -acetylcysteine diminished reactive oxygen species (ROS), restoring iHR and HR levels. Our findings show that mutated FLT3-ITD and JAK2 augment ROS production and HR, shifting the cellular milieu toward illegitimate recombination events such as iHR and CN-LOH. Therapeutic reduction of ROS may thus prevent leukemic progression and relapse in myeloid malignancies. Cancer Res; 77(7); 1697-708. ©2017 AACR . ©2017 American Association for Cancer Research.

Pim kinase inhibition sensitizes FLT3-ITD acute myeloid leukemia cells to topoisomerase 2 inhibitors through increased DNA damage and oxidative stress

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Doshi, Kshama A.; Trotta, Rossana; Natarajan, Karthika; Rassool, Feyruz V.; Tron, Adriana E.; Huszar, Dennis; Perrotti, Danilo; Baer, Maria R.

2016-01-01

Internal tandem duplication of fms-like tyrosine kinase-3 (FLT3-ITD) is frequent (30 percent) in acute myeloid leukemia (AML), and is associated with short disease-free survival following chemotherapy. The serine threonine kinase Pim-1 is a pro-survival oncogene transcriptionally upregulated by FLT3-ITD that also promotes its signaling in a positive feedback loop. Thus inhibiting Pim-1 represents an attractive approach in targeting FLT3-ITD cells. Indeed, co-treatment with the pan-Pim kinase inhibitor AZD1208 or expression of a kinase-dead Pim-1 mutant sensitized FLT3-ITD cell lines to apoptosis triggered by chemotherapy drugs including the topoisomerase 2 inhibitors daunorubicin, etoposide and mitoxantrone, but not the nucleoside analog cytarabine. AZD1208 sensitized primary AML cells with FLT3-ITD to topoisomerase 2 inhibitors, but did not sensitize AML cells with wild-type FLT3 or remission bone marrow cells, supporting a favorable therapeutic index. Mechanistically, the enhanced apoptosis observed with AZD1208 and topoisomerase 2 inhibitor combination treatment was associated with increased DNA double-strand breaks and increased levels of reactive oxygen species (ROS), and co-treatment with the ROS scavenger N-acetyl cysteine rescued FLT3-ITD cells from AZD1208 sensitization to topoisomerase 2 inhibitors. Our data support testing of Pim kinase inhibitors with topoisomerase 2 inhibitors, but not with cytarabine, to improve treatment outcomes in AML with FLT3-ITD. PMID:27374090

A randomized assessment of adding the kinase inhibitor lestaurtinib to first-line chemotherapy for FLT3-mutated AML

DEFF Research Database (Denmark)

Knapper, Steven; Russell, Nigel; Gilkes, Amanda

2017-01-01

The clinical benefit of adding FMS-like tyrosine kinase-3 (FLT3)-directed small molecule therapy to standard first-line treatment of acute myeloid leukemia (AML) has not yet been established. As part of the UK AML15 and AML17 trials, patients with previously untreated AML and confirmed FLT3-activ...

Incidence and significance of FLT3-ITD and NPM1 mutations in patients with normal karyotype acute myeloid leukaemia.

LENUS (Irish Health Repository)

Haslam, K

2012-02-01

BACKGROUND: Acute myeloid leukaemia (AML) is a heterogeneous clonal disorder of haematopoietic progenitor cells. Approximately half of all adult AML patients have a normal karyotype (NK-AML) and an intermediate risk prognosis. AIMS: To determine the incidence and prognostic significance of NPM1 and FLT3-ITD mutations in a population of patients with NK-AML. METHODS: FLT3-ITD and NPM1 mutation status was retrospectively sought in presentation samples from 44 NK-AML patients. RESULTS: FLT3-ITD and NPM1 mutations were detected in 45.5 and 54.5% of patients, respectively, allowing stratification according to genotype. CONCLUSIONS: FLT3-ITD and NPM1 mutation status can be defined in NK-AML. Prospective screening for these mutations is advocated in all NK-AML patients, as the genotype is of clinical importance when considering treatment options including stem cell transplantation.

Heterogeneity in stabilization phenomena in FLT PET images of canines

International Nuclear Information System (INIS)

Simoncic, Urban; Jeraj, Robert

2014-01-01

3'-( 18 F)fluoro-3'-deoxy-L-thymidine (FLT) is a PET marker of cellular proliferation. Its tissue uptake rate is often quantified with a Standardized Uptake Value (SUV), although kinetic analysis provides a more accurate quantification. The purpose of this study is to investigate the heterogeneity in FLT stabilization phenomena. The study was done on 15 canines with spontaneously occurring sinonasal tumours. They were imaged dynamically for 90 min with FLT PET/CT twice; before and during the radiotherapy. Images were analyzed for kinetics on a voxel basis through compartmental analysis. Stabilization curves were calculated as a time-dependant correlation between the time-dependant SUV and the kinetic parameters (voxel values within the tumour were correlated). Stabilization curves were analyzed for stabilization speed, maximal correlation and correlation decrease following the maximal correlation. These stabilization parameters were correlated with the region-averaged kinetic parameters. The FLT SUV was highly correlated with vasculature fraction immediately post-injection, followed by maximum in correlation with the perfusion/permeability. At later times post-injection the FLT SUV was highly correlated (Pearson correlation coefficient above 0.95) with the FLT influx parameter for cases with tumour-averaged SUV 30–50 min above 2, while others were indeterminate (correlation coefficients from 0.1 to 0.97). All cases with highly correlated SUV and FLT influx parameter had correlation coefficient within 0.5% of its maximum in the period of 30–50 min post-injection. Stabilization time was inversely proportional to the FLT influx rate. Correlation between the FLT SUV and FLT influx parameter dropped at later times post-injection with drop being proportional to the dephosphorylation rate. The FLT was found to be metabolically stable in canines. FLT PET imaging protocol should define minimal and maximal FLT uptake period, which would be 30–50�

Pre-apoptotic response to therapeutic DNA damage involves protein modulation of Mcl-1, Hdm2 and Flt3 in acute myeloid leukemia cells

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Hovland Randi

2007-05-01

Full Text Available Abstract Background Acute myeloid leukemia (AML cells are characterized by non-mutated TP53, high levels of Hdm2, and frequent mutation of the Flt3 receptor tyrosine kinase. The juxtamembrane mutation of FLT3 is the strongest independent marker for disease relapse and is associated with elevated Bcl-2 protein and p53 hyper-phosphorylation in AML. DNA damage forms the basic mechanism of cancer cell eradication in current therapy of AML. Hdm2 and pro-apoptotic Bcl-2 members are among the most intensely induced genes immediately after chemotherapy and Hdm2 is proposed a role in receptor tyrosine kinase regulation. Thus we examined the DNA damage related modulation of these proteins in relation to FLT3 mutational status and induction of apoptosis. Results Within one hour after exposure to ionizing radiation (IR, the AML cells (NB4, MV4-11, HL-60, primary AML cells showed an increase in Flt3 protein independent of mRNA levels, while the Hdm2 protein decreased. The FLT3 mutant MV4-11 cells were resistant to IR accompanied by presence of both Mcl-1 and Hdm2 protein three hours after IR. In contrast, the FLT3 wild type NB4 cells responded to IR with apoptosis and pre-apoptotic Mcl-1 down regulation. Daunorubicin (DNR induced continuing down regulation of Hdm2 and Mcl-1 in both cell lines followed by apoptosis. Conclusion Both IR and DNR treatment resulted in concerted protein modulations of Mcl-1, Hdm2 and Flt3. Cell death induction was associated with persistent attenuation of Mcl-1 and Hdm2. These observations suggest that defining the pathway(s modulating Flt3, Hdm2 and Mcl-1 may propose new strategies to optimize therapy for the relapse prone FLT3 mutated AML patients.

Molecular imaging of proliferation with [{sup 18}F]FLT-PET; Molekulare Bildgebung der Proliferation mit [{sup 18}F]FLT-PET

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Buck, A.K.; Herrmann, K.; Schwaiger, M.; Wester, H.J. [Klinikum rechts der Isar, Technische Univ. Muenchen (Germany). Nuklearmedizinische Klinik und Poliklinik; Dechow, T.; Graf, N. [Klinikum rechts der Isar, Technische Univ. Muenchen (Germany). Medizinische Klinik III, Haematologi/Onkologie

2009-06-15

An increased proliferation fraction is a hallmark of malignant cells and a specific feature of malignant tumors which potentially allows more specific tumor imaging compared to increased glucose consumption (FDG-PET). The majority of therapeutic approaches aim at inhibition of proliferation or induction of apoptosis. Accordingly, non-invasive assessment of the proliferation fraction is also of interest for monitoring response to treatment and to early detect resistance to a specific kind of therapy. In clinical studies it has been demonstrated that the radiotracer 3'-deoxy-3'-[{sup 18}F]fluorothymidine (FLT) accumulates specifically in malignant tumors. Regression analysis of tumoral FLT-uptake and immunohistochemically detected proliferation fraction (PCNA, Ki-67) resulted in a significant correlation (e.g., in lung cancer, correlation coefficient r=0.87, p<0.0001). The possibility to non-invasively assess the proliferation fraction with FLT-PET has been shown in a variety of solid cancers. Compared to the standard radiotracer FDG, superior demonstration of the proliferative activity using FLT as the tracer has been demonstrated. On the other hand, accumulation of FLT was significantly lower compared to FDG. Malignant tumors with low proliferation rates did not present with increased FLT-uptake resulting in a reduced sensitivity. In lung cancer for example, the sensitivity was 86% of FLT-PET compared to 100% of FDG-PET. Also, regarding detection of locoregional lymph node metastases or distant metastases, FDG-PET was shown to have a higher sensitivity. Due to the reduced sensitivity, there is no advantage of specific imaging of tumor proliferation regarding tumor staging. In malignant lymphoma, FLT was similar effective for tumor staging as compared to FDG-PET. In a pilot study comprising 34 patients, both tracers showed a similar sensitivity regarding detection of lymphoma. An observed specificity of 100% indicates that FLT-PET represents a diagnostic

Unlocking the potential of translation for FLT

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Alenka Kocbek

2014-12-01

Full Text Available The paper proposes unlocking the potential of translation for foreign language teaching (FLT by seeking to create synergies with the related discipline of translation science (TS. This aim is in keeping with the guidelines for language teaching provided in the Common European Framework of Languages, which introduced a model of communicative competences including communicative language competences as those which enable a person to act by drawing on specific linguistic means. First, an overview of the changing status of translation in FLT is presented – from its being considered a fundamental teaching method and basic skill in the Grammar-Translation Method, to its being all but outlawed in more recent communicative and task-based approaches, to its final rehabilitation in recent decades. It is then shown that, in the development of FLT, the parallel evolution of TS somehow failed to be acknowledged and, consequently, the opportunity to create valuable synergies between the two disciplines was missed. Following the stance of authors who have advocated the use of translation in FLT, it is argued that translation can effectively supplement the development of the four traditional language skills and, moreover, that some of the insights developed by TS can effectively be integrated into FLT as strategies aimed at enhancing leaners’ cross-cultural communicative competences. To this purpose, selected insights from TS (e.g. the functional approach and the skopos theory, the cultureme model, the theory of memes are discussed and their potential for creating synergies with FLT are explored. Finally, the paper discusses the omnipresence of different forms of translation and interpreting in contemporary societies and shows that this naturally and logically calls for a systematic inclusion of translation in FLT.

Mutation Analysis of JAK2V617F, FLT3-ITD, NPM1, and DNMT3A in Chinese Patients with Myeloproliferative Neoplasms

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Min Wang

2014-01-01

Full Text Available Since the discovery of JAK2V617F tyrosine kinase-activating mutation, several genes have been found mutated in myeloproliferative neoplasms (MPNs. FLT3-ITD, NPM1, and DNMT3A mutations frequently occurred in AML patients and have been found conferred with myeloproliferative neoplasms in mouse model. Therefore, we sought to search for mutations in JAK2V617F, FLT3-ITD, NPM1, and DNMT3A in 129 cases including 120 classic MPN cases and 9 MDS/MPN cases. JAK2V617F mutation was found in 60% of the 120 classic MPNs. However, none of the patients displayed FLT3-ITD and NPM1 mutations; only 2 patients harbored DNMT3A R882 mutation. Further studies including whole-genome sequence will be conducted to investigate the possible involvement of these genes in MPN.

SOCS1 cooperates with FLT3-ITD in the development of myeloproliferative disease by promoting the escape from external cytokine control

DEFF Research Database (Denmark)

Reddy, P.N.G.; Serve, H.; Brandts, C.H.

2012-01-01

Activating mutations in the receptor tyrosine kinase FLT3 are frequently found in acute myelogenous leukemia patients and confer poor clinical prognosis. It is unclear how leukemic blasts escape cytokine control that regulates normal hematopoiesis. We have recently demonstrated that FLT3-internal...

The Coordinated P53 and Estrogen Receptor Cis-Regulation at an FLT1 Promoter SNP Is Specific to Genotoxic Stress and Estrogenic Compound

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Langen, Jan-Stephan; Schoenfelder, Gilbert; Resnick, Michael A.; Inga, Alberto

2010-01-01

Background Recently, we established that a C>T single nucleotide polymorphism (SNP) in the promoter of the VEGF receptor FLT1 gene generates a ½ site p53 response element (RE-T) that results in p53 responsiveness of the promoter. The transcriptional control required an estrogen receptor (ER) ½ site response element (ERE1) 225 nt upstream to the RE-T. Methodology/Principal Findings Here we report the identification of a second ER ½ site (ERE2) located 145 bp downstream of the RE-T and establish that both EREs can impact p53-mediated transactivation of FLT1-T in a manner that is cell type and ER level dependent. Gene reporter assays and ChIP experiments conducted in the breast cancer-derived MCF7 cells revealed that the ERE2 site was sufficient for p53-mediated ERα recruitment and transactivation of the FLT1-T promoter/reporter construct. Surprisingly, unlike the case for other p53 target promoters, p53-mediated transactivation of FLT1-T constructs or expression of the endogenous FLT1 gene, as well as binding of p53 and ER at the promoter constructs, was inducible by doxorubicin but not by 5-fluorouracil. Furthermore, ER activity at FLT1-T was differentially affected by ER ligands, compared to a control TFF1/pS2 ER target promoter. The p53-related transcription factors (TFs) p73 and p63 had no effect on FLT1 transactivation. Conclusions/Significance We establish a new dimension to the p53 master regulatory network where p53-mediated transcription from a ½ site RE can be determined by ER binding at one or more cis-acting EREs in manner that is dependent on level of ER protein, the type of ER ligand and the specific p53-inducing agent. PMID:20422012

Spatiotemporal Stability of Cu-ATSM and FLT Positron Emission Tomography Distributions During Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Bradshaw, Tyler J.; Yip, Stephen; Jallow, Ngoneh [Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin (United States); Forrest, Lisa J. [Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin (United States); Jeraj, Robert, E-mail: rjeraj@wisc.edu [Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin (United States); Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin (United States)

2014-06-01

Purpose: In dose painting, in which functional imaging is used to define biological targets for radiation therapy dose escalation, changes in spatial distributions of biological properties during treatment can compromise the quality of therapy. The goal of this study was to assess the spatiotemporal stability of 2 potential dose painting targets—hypoxia and proliferation—in canine tumors during radiation therapy. Methods and Materials: Twenty-two canine patients with sinonasal tumors (14 carcinoma and 8 sarcoma) were imaged before hypofractionated radiation therapy with copper(II)-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) positron emission tomography/computed tomography (PET/CT) for hypoxia and 3′-deoxy-3′-{sup 18}F-fluorothymidine (FLT) PET/CT for proliferation. The FLT scans were repeated after 2 fractions and the Cu-ATSM scans after 3 fractions. Midtreatment PET/CT images were deformably registered to pretreatment PET/CT images. Voxel-based Spearman correlation coefficients quantified the spatial stability of Cu-ATSM and FLT uptake distributions between pretreatment and midtreatment scans. Paired t tests determined significant differences between the patients' respective Cu-ATSM and FLT correlations coefficients. Standardized uptake value measures were also compared between pretreatment and midtreatment scans by use of paired t tests. Results: Spatial distributions of Cu-ATSM and FLT uptake were stable through midtreatment for both sarcomas and carcinomas: the population mean ± standard deviation in Spearman correlation coefficient was 0.88 ± 0.07 for Cu-ATSM and 0.79 ± 0.13 for FLT. The patients' Cu-ATSM correlation coefficients were significantly higher than their respective FLT correlation coefficients (P=.001). Changes in Cu-ATSM SUV measures from pretreatment to midtreatment were histology dependent: carcinomas experienced significant decreases in Cu-ATSM uptake (P<.05), whereas sarcomas did not (P>.20). Both histologies

FLT3 mutations in early T-cell precursor ALL characterize a stem cell like leukemia and imply the clinical use of tyrosine kinase inhibitors.

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Martin Neumann

Full Text Available Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL has been identified as high-risk subgroup of acute T-lymphoblastic leukemia (T-ALL with a high rate of FLT3-mutations in adults. To unravel the underlying pathomechanisms and the clinical course we assessed molecular alterations and clinical characteristics in a large cohort of ETP-ALL (n = 68 in comparison to non-ETP T-ALL adult patients. Interestingly, we found a high rate of FLT3-mutations in ETP-ALL samples (n = 24, 35%. Furthermore, FLT3 mutated ETP-ALL was characterized by a specific immunophenotype (CD2+/CD5-/CD13+/CD33-, a distinct gene expression pattern (aberrant expression of IGFBP7, WT1, GATA3 and mutational status (absence of NOTCH1 mutations and a low frequency, 21%, of clonal TCR rearrangements. The observed low GATA3 expression and high WT1 expression in combination with lack of NOTCH1 mutations and a low rate of TCR rearrangements point to a leukemic transformation at the pluripotent prothymocyte stage in FLT3 mutated ETP-ALL. The clinical outcome in ETP-ALL patients was poor, but encouraging in those patients with allogeneic stem cell transplantation (3-year OS: 74%. To further explore the efficacy of targeted therapies, we demonstrate that T-ALL cell lines transfected with FLT3 expression constructs were particularly sensitive to tyrosine kinase inhibitors. In conclusion, FLT3 mutated ETP-ALL defines a molecular distinct stem cell like leukemic subtype. These data warrant clinical studies with the implementation of FLT3 inhibitors in addition to early allogeneic stem cell transplantation for this high risk subgroup.

Synthesis and labeling 5'-O-(4-4'-dimetoxytrityl) -2,3-anhidrothymidine for preparation of radiopharmaceutical [18F]FLT

International Nuclear Information System (INIS)

Purwoko; Maskur; Chaeruman; Sugiarto, Yono

2013-01-01

It is has been known that the compound of 3'-deoxy-3,-( 18 F] Fluorothymidine or ( 18 F] FLT is a thymidine derivative radiopharmaceutical used for cancer detection based on DNA metabolism. Synthesis and labeling of 5'-0-(4,4 '-dimetoxytrityl) -2,3' anhidrothymidine precursor for preparation of the radiopharmaceutical [ 18 F]FL T was carried out. The precursor was synthesized in similar manner and procedure literature and it have been obtained a crystalline product with total yield of 32,4 %. The chemical purity of the product which determined by HPLC was found to be more than 95%. Characterization of the product was done by observing the results of the LC / MS and 1 H-NMR test, the resulted data were found to be very closed to those reported in the literature. Labeling of the precursor was done by nucleophilic fluorination reactions using 18 Fluoride at 160 °C for 15 minutes with kryptofix 2.2.2 catalyst followed hydrolysis using HCI at 100 °C for 10 minutes and then neutralized with NaOH. Purification [ 18 F]FLT was performed by single cartridge Alumina-N as a substitute HPLC methods. The results have been obtained a label compound [ 18 F]FLT with high purity as a bulk for preparation of the radiopharmaceutical [ 18 F]FLT. The label compound of [ 18 F]FLT undergone a quality test which included a clarity, pH and a radiochemical purity. The results of quality control on four batches of [ 18 F]FLT showed that these products were colorless clear solution with pH between 6.0-7.5, and radiochemical purity 97.93 ± 1,48% and showed that the label compounds have been obtained [ 18 F]FLT-free particles form a clear solution with a pH between 6,0 - 7,5, radiochemical purity of 97.93 ± 1,48 %, radiochemical yields 8.18 ± 1.54% (decay uncorrected) and processing time 73 ± 4 minutes. (author)

[Use of sFlt-1/PlGF ratio in preeclampsia : a monocentric retrospective analysis].

Science.gov (United States)

Verbeurgt, L; Chantraine, F; De Marchin, J; Minon, J-M; Nisolle, M

2017-09-01

Soluble Fms-like tyrosine kinase 1 (sFlt-1) is an anti-angiogenic factor released in higher amounts in preeclampsia and implicated in endothelial dysfunction. sFlt-1/PlGF ratio is used in the prediction of preeclampsia. An sFlt-1/PlGF ratio inferior to 38 predicts the short-term absence of preeclampsia. A ratio ? 85 (early-onset PE) or ? 110 (late-onset of PE) could diagnose preeclampsia. In this study, sFlt-1/PlGF ratio has been measured in 183 patients. Sixty-seven preeclampsia have been diagnosed preeclamptic at delivery. The median sFlt-1/PlGF ratio was 100.3. The median ratio among women with preeclampsia (N=67) versus no preeclampsia (N=116) was 212.7 versus 35.4. In accordance with this analysis, an sFlt-1/PlGF ratio ? 38 has a sensibility of 95,5 % and a specificity of 73.3 %. The positive predictive value and the negative predictive value were 67.4 % and 96.6 %, respectively. These results suggest that sFlt-1/PlGF ratio is helpful in the diagnosis of preeclampsia.

Intra-individual comparison of F-18-FLT PET and F-18 FET PET in brain tumor patients

International Nuclear Information System (INIS)

Kim, S.; Cheon, G.J.; Cho, Y.S.; Kwak, H.S.; Lee, C.H.; Choi, C.W.; Lim, S.M.

2004-01-01

Full text: The nucleoside analogue 18F-3'-deoxy-3'-fluorothymidine (FLT) for cellular proliferation and the amino acid analogue O- (2'18F-fluoroethyl)-L-tyrosine (FET) are recently developed PET-tracer for tumor imaging. Previous studies have demonstrated that the diagnostic ability of FET PET better than FDG PET in patient with newly diagnosed or recurrent brain tumors after radiation therapy. To compare findings on FLT PET with FET PET, we prospectively undertook FLT, FET and FDG PET in same patient with suspected primary/metastatic and recurrent brain tumors. Seventeen studies (FLT +FET + FDG: 13, FLT+FDG: 3, FLT +FET: 1) in 16 consecutive patients (47 ± 8.3 years, M: F 10: 6) with brain tumor (3 for initial diagnosis, 6 for therapeutic response, 6 for detecting recurrence, 1 for diagnosis and recurrence both) were included. Brain tumors were 14 gliomas (6 high-grade, 9 low-grade by the WHO classification), 2 metastatic brain tumors and 1 CNS lymphoma. 18F-FDG, FLT and FET PET were performed within two weeks. Attenuation-corrected brain images were acquired 30 minutes after injection of 370-555 MBq FDG, FLT and FET with a dedicated PET scanner (ECAT HR+ scanner, Siemens-CTI, Knoxville, Tenn., USA). Maximum SUV (max SUV) and relative uptake defined by FLT and FET accumulation within the tumor in relation to a contra lateral control region (max SUV for tumor/mean SUV for contra lateral normal gray matter) were calculated. A total of 26 tumor foci (26 on FLT and FDG, 22 on FET) in 17 studies were analysed. In most of tumor foci (20 of 22) FLT and FET PET images showed a similar extent of tumor activity. In 2 tumor foci discrepant findings were noticed; intense FLT uptake with negative FLT uptake in primary CNS lymphoma and negative FLT uptake with mild FET uptake in low-grade astrocytoma. Overall positive FLT, FET and FDG uptakes were 85 % (22/26), 90 % (18/ 20) and 58 % (15/26) respectively. Max SUV and relative FLT/FET uptake: The mean max SUV of FLT (0.97 ± 0

Sorafenib promotes graft-versus-leukemia activity in mice and humans through IL-15 production in FLT3-ITD-mutant leukemia cells.

Science.gov (United States)

Mathew, Nimitha R; Baumgartner, Francis; Braun, Lukas; O'Sullivan, David; Thomas, Simone; Waterhouse, Miguel; Müller, Tony A; Hanke, Kathrin; Taromi, Sanaz; Apostolova, Petya; Illert, Anna L; Melchinger, Wolfgang; Duquesne, Sandra; Schmitt-Graeff, Annette; Osswald, Lena; Yan, Kai-Li; Weber, Arnim; Tugues, Sonia; Spath, Sabine; Pfeifer, Dietmar; Follo, Marie; Claus, Rainer; Lübbert, Michael; Rummelt, Christoph; Bertz, Hartmut; Wäsch, Ralph; Haag, Johanna; Schmidts, Andrea; Schultheiss, Michael; Bettinger, Dominik; Thimme, Robert; Ullrich, Evelyn; Tanriver, Yakup; Vuong, Giang Lam; Arnold, Renate; Hemmati, Philipp; Wolf, Dominik; Ditschkowski, Markus; Jilg, Cordula; Wilhelm, Konrad; Leiber, Christian; Gerull, Sabine; Halter, Jörg; Lengerke, Claudia; Pabst, Thomas; Schroeder, Thomas; Kobbe, Guido; Rösler, Wolf; Doostkam, Soroush; Meckel, Stephan; Stabla, Kathleen; Metzelder, Stephan K; Halbach, Sebastian; Brummer, Tilman; Hu, Zehan; Dengjel, Joern; Hackanson, Björn; Schmid, Christoph; Holtick, Udo; Scheid, Christof; Spyridonidis, Alexandros; Stölzel, Friedrich; Ordemann, Rainer; Müller, Lutz P; Sicre-de-Fontbrune, Flore; Ihorst, Gabriele; Kuball, Jürgen; Ehlert, Jan E; Feger, Daniel; Wagner, Eva-Maria; Cahn, Jean-Yves; Schnell, Jacqueline; Kuchenbauer, Florian; Bunjes, Donald; Chakraverty, Ronjon; Richardson, Simon; Gill, Saar; Kröger, Nicolaus; Ayuk, Francis; Vago, Luca; Ciceri, Fabio; Müller, Antonia M; Kondo, Takeshi; Teshima, Takanori; Klaeger, Susan; Kuster, Bernhard; Kim, Dennis Dong Hwan; Weisdorf, Daniel; van der Velden, Walter; Dörfel, Daniela; Bethge, Wolfgang; Hilgendorf, Inken; Hochhaus, Andreas; Andrieux, Geoffroy; Börries, Melanie; Busch, Hauke; Magenau, John; Reddy, Pavan; Labopin, Myriam; Antin, Joseph H; Henden, Andrea S; Hill, Geoffrey R; Kennedy, Glen A; Bar, Merav; Sarma, Anita; McLornan, Donal; Mufti, Ghulam; Oran, Betul; Rezvani, Katayoun; Shah, Omid; Negrin, Robert S; Nagler, Arnon; Prinz, Marco; Burchert, Andreas; Neubauer, Andreas; Beelen, Dietrich; Mackensen, Andreas; von Bubnoff, Nikolas; Herr, Wolfgang; Becher, Burkhard; Socié, Gerard; Caligiuri, Michael A; Ruggiero, Eliana; Bonini, Chiara; Häcker, Georg; Duyster, Justus; Finke, Jürgen; Pearce, Erika; Blazar, Bruce R; Zeiser, Robert

2018-03-01

Individuals with acute myeloid leukemia (AML) harboring an internal tandem duplication (ITD) in the gene encoding Fms-related tyrosine kinase 3 (FLT3) who relapse after allogeneic hematopoietic cell transplantation (allo-HCT) have a 1-year survival rate below 20%. We observed that sorafenib, a multitargeted tyrosine kinase inhibitor, increased IL-15 production by FLT3-ITD + leukemia cells. This synergized with the allogeneic CD8 + T cell response, leading to long-term survival in six mouse models of FLT3-ITD + AML. Sorafenib-related IL-15 production caused an increase in CD8 + CD107a + IFN-γ + T cells with features of longevity (high levels of Bcl-2 and reduced PD-1 levels), which eradicated leukemia in secondary recipients. Mechanistically, sorafenib reduced expression of the transcription factor ATF4, thereby blocking negative regulation of interferon regulatory factor 7 (IRF7) activation, which enhanced IL-15 transcription. Both IRF7 knockdown and ATF4 overexpression in leukemia cells antagonized sorafenib-induced IL-15 production in vitro. Human FLT3-ITD + AML cells obtained from sorafenib responders following sorafenib therapy showed increased levels of IL-15, phosphorylated IRF7, and a transcriptionally active IRF7 chromatin state. The mitochondrial spare respiratory capacity and glycolytic capacity of CD8 + T cells increased upon sorafenib treatment in sorafenib responders but not in nonresponders. Our findings indicate that the synergism of T cells and sorafenib is mediated via reduced ATF4 expression, causing activation of the IRF7-IL-15 axis in leukemia cells and thereby leading to metabolic reprogramming of leukemia-reactive T cells in humans. Therefore, sorafenib treatment has the potential to contribute to an immune-mediated cure of FLT3-ITD-mutant AML relapse, an otherwise fatal complication after allo-HCT.

Noninvasive quantification of 18F-FLT human brain PET for the assessment of tumour proliferation in patients with high-grade glioma

International Nuclear Information System (INIS)

Backes, Heiko; Ullrich, Roland; Neumaier, Bernd; Kracht, Lutz; Wienhard, Klaus; Jacobs, Andreas H.

2009-01-01

Compartmental modelling of 3 ' -deoxy-3 ' -[ 18 F]-fluorothymidine ( 18 F-FLT) PET-derived kinetics provides a method for noninvasive assessment of the proliferation rate of gliomas. Such analyses, however, require an input function generally derived by serial blood sampling and counting. In the current study, 18 F-FLT kinetic parameters obtained from image-derived input functions were compared with those from input functions derived from arterialized blood samples. Based on the analysis of 11 patients with glioma (WHO grade II-IV) a procedure for the automated extraction of an input function from 18 F-FLT brain PET data was derived. The time-activity curve of the volume of interest with the maximum difference in 18 F-FLT uptake during the first 5 min after injection and the period from 60 to 90 min was corrected for partial-volume effects and in vivo metabolism of 18 F-FLT. For each patient a two-compartment kinetic model was applied to the tumour tissue using the image-derived input function. The resulting kinetic rate constants K 1 (transport across the blood-brain barrier) and K i (metabolic rate constant or net influx constant) were compared with those obtained from the same data using the input function derived from blood samples. Additionally, the metabolic rate constant was correlated with the frequency of tumour cells stained with Ki-67, a widely used immunohistochemical marker of cell proliferation. The rate constants from kinetic modelling were comparable when the blood sample-derived input functions were replaced by the image-derived functions (K 1,img and K 1,sample , r = 0.95, p -5 ; K i,img and K i,sample , r = 0.86, p 1,img and K 1,sample , p = 0.20; K i,img and K i,sample , p = 0.92). Furthermore, a significant correlation between K i,img and the percentage of Ki-67-positive cells was observed (r = 0.73, p = 0.01). Kinetic modelling of 18 F-FLT brain PET data using image-derived input functions extracted from human brain PET data with the practical

A new class of PN3-pincer ligands for metal–ligand cooperative catalysis

KAUST Repository

Li, Huaifeng

2014-12-01

Work on a new class of PN3-pincer ligands for metal-ligand cooperative catalysis is reviewed. While the field of the pyridine-based PN3-transition metal pincer complexes is still relatively young, many important applications of these complexes have already emerged. In several cases, the PN3-pincer complexes for metal-ligand cooperative catalysis result in significantly improved or unprecedented activities. The synthesis and coordination chemistry of PN3-pincer ligands are briefly summarized first to cover the synthetic routes for their preparation, followed by a focus review on their applications in catalysis. A specific emphasis is placed on the later section about the role of PN3-pincer ligands\\' dearomatization-rearomatization steps during the catalytic cycles. The mechanistic insights from density functional theory (DFT) calculations are also discussed.

A new class of PN3-pincer ligands for metal–ligand cooperative catalysis

KAUST Repository

Li, Huaifeng; Zheng, Bin; Huang, Kuo-Wei

2014-01-01

Work on a new class of PN3-pincer ligands for metal-ligand cooperative catalysis is reviewed. While the field of the pyridine-based PN3-transition metal pincer complexes is still relatively young, many important applications of these complexes have already emerged. In several cases, the PN3-pincer complexes for metal-ligand cooperative catalysis result in significantly improved or unprecedented activities. The synthesis and coordination chemistry of PN3-pincer ligands are briefly summarized first to cover the synthetic routes for their preparation, followed by a focus review on their applications in catalysis. A specific emphasis is placed on the later section about the role of PN3-pincer ligands' dearomatization-rearomatization steps during the catalytic cycles. The mechanistic insights from density functional theory (DFT) calculations are also discussed.

Release of soluble vascular endothelial growth factor receptor-1 (sFlt-1 during coronary artery bypass surgery

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Orsel Isabelle

2007-09-01

Full Text Available Abstract Background This study was conducted to follow plasma concentrations of sFlt-1 and sKDR, two soluble forms of the vascular endothelial growth factor (VEGF receptor in patients undergoing coronary artery bypass graft (CABG surgery with extracorporeal circulation (ECC. Methods Plasma samples were obtained before, during and after surgery in 15 patients scheduled to undergo CABG. Levels of sFlt-1 and KDR levels were investigated using specific ELISA. Results A 75-fold increase of sFlt-1 was found during cardiac surgery, sFlt-1 levels returning to pre-operative values at the 6th post-operative hour. In contrast sKDR levels did not change during surgery. The ECC-derived sFlt-1 was functional as judge by its inhibitory effect on the VEGF mitogenic response in human umbilical vein endothelial cells (HUVECs. Kinetic experiments revealed sFlt-1 release immediately after the beginning of ECC suggesting a proteolysis of its membrane form (mFlt-1 rather than an elevated transcription/translation process. Flow cytometry analysis highlighted no effect of ECC on the shedding of mFlt-1 on platelets and leukocytes suggesting vascular endothelial cell as a putative cell source for the ECC-derived sFlt-1. Conclusion sFlt-1 is released during CABG with ECC. It might be suggested that sFlt-1 production, by neutralizing VEGF and/or by inactivating membrane-bound Flt-1 and KDR receptors, might play a role in the occurrence of post-CABG complication.

Intraindividual comparison of F-18-FLT PET and F-18 FET PET in brain tumor patients

International Nuclear Information System (INIS)

Kim, Sung Eun; Cheon, G. J.; Cho, Y. S.; Kwak, H. S.; Lee, C. H.; Choi, C. W.; Lim, S. M.

2003-01-01

To compare findings on FLT PET with FET PET, we prospectively undertaken FLT, FET and FDG PET in same patient with suspected primary/metastatic and recurrent brain tumors. Seventeen studies in 16 patients (47 8.3 years, M: F 10: 6) with brain tumor (3 for initial diagnosis, 6 for therapeutic response, 6 for detecting recurrence, 1 for diagnosis and recurrence both) were included. Brain tumors were 14 gliomas (6 high- grade 9 low-grade by the WHO classification), 2 metastatic brain tumors and 1 CNS lymphoma. 18F-FDG, FLT and FET PET were performed within two weeks. Attenuation-corrected brain images were acquired 30 minutes after injection of 370-555 MBq FDG, FLT and FET with a dedicated PET scanner (ECAT HR scanner, Siemens-CTI). Maximum SUV (max SUV) and relative uptake defined by FLT and FET accumulation within the tumor in relation to a contralateral control region (max SUV for tumor/ mean SUV for contralateral normal gray matter) were calculated. 26 tumor foci were analyzed. Relative FLT uptake (4.17 2.4, 0.58 to 7.45) was grater than than FET uptake (2.03 1.17, 0.92 to 4.53 (p<0.0006)) and FDG uptake (1.16 0.34, 0.76 to 2.08). Among FLT, FET and FDG uptakes in 20 tumor foci, correlation were poor. the relative FLT uptake of high-grade glioma was higher than low-glioma (6.070.76 vs 3.11 2.15, p=0.002), however, relative FET uptake was not different significantly (2.68 1.51, high-grade vs 1.970.78, low-grade). The correlation between tumor grade (high vs low grade) and relative uptake (FLT and FET) was shown only with relative FLT uptake (r=0.62, p=0.002). The best cut off value of relative FLT uptake between high-grade and low-grade glioma was 4.54 (AUC: 0.89 sensitivity: 100 specificity: 86.7%). Compared with FET uptake, FLT uptake showed much higher contrast and associated with tumor grade. Further study, evaluation of proliferative index of Ki-67 and its relationship with FLT and FET uptake, are ongoing

Microwave mediated radiosynthesis of [F-18] FLT and its in-vitro study with androgen independent human prostate cancer cell line (PC-3)

International Nuclear Information System (INIS)

Ponde, D.E.; Dence, C.S.; Oyama, N.; Welch, M.J.

2003-01-01

The aim of this work was to improve the radiosynthesis of [F-18] FLT and to study its usefulness in monitoring change of proliferative activity of prostate cancer cells in the early phase of therapy. Method: Starting with anhydrothymidine, [F-18] FLT was synthesized by microwave mediated nucleophilic displacement by fluoride ion followed by acid hydrolysis in a synthesis time of just 55 minutes, which included Oasis solid phase and HPLC purification. The total radiochemical yield was 10-15% (at EOS), and the radiochemical purity was >99%. An in vitro study was carried out with androgen-independent human prostate cancer cell line PC-3. Two X 10e5 cells were seeded in 6 well plates with Ham's F-12K medium with 2 mM L-glutamine adjusted to contain 1.5 g/L sodium bicarbonate supplemented with 10% heat activated FBS. One day later, PC-3 cells were at 50% confluent, the media was removed and the cells divided into two groups. In one group, cells were suspended in fresh media as above with 10% FBS, whereas in the other group cells were suspended in fresh media as above but without serum. Twenty-four hours later, [F-18] FLT was added to each flask (n=3). The cell-associated uptake of [F-18] FLT at 37 deg C was determined at 0, 1, 3, and 6 h after incubation. [F-18] FLT uptake in PC-3 cells decreased by 55% (from 9% to 4%) after 24h incubation with serum free media, indicating its potential usefulness to monitor cell proliferation in androgen-independent human prostate cancer. Studies to ascertain the uptake-mechanism are in the way. NIH grant HL13851

Serum Soluble Fms-Like Tyrosine Kinase 1 (sFlt-1 Predicts the Severity of Acute Pancreatitis

Directory of Open Access Journals (Sweden)

Paulina Dumnicka

2016-12-01

Full Text Available Organ failure is the most important determinant of the severity of acute pancreatitis (AP. Soluble fms-like tyrosine kinase 1 (sFlt-1 is positively associated with organ failure in sepsis. Our aim was to evaluate the diagnostic utility of automated sFlt-1 measurements for early prediction of AP severity. Adult patients (66 with AP were recruited, including 46 with mild (MAP, 15 with moderately-severe (MSAP and 5 with severe AP (SAP. Serum and urine samples were collected twice. Serum sFlt-1 was measured with automated electrochemiluminescence immunoassay. Serum concentrations of sFlt-1 were significantly higher in patients with MSAP and SAP as compared to MAP. SAP patients had the highest concentrations. At 24 and 48 h, sFlt-1 positively correlated with inflammatory markers (leukocyte count, C-reactive protein, kidney function (creatinine, urea, cystatin C, serum and urine neutrophil gelatinase-associated lipocalin, urine albumin/creatinine ratio, D-dimer and angiopoietin-2. sFlt-1 positively correlated with the bedside index of severity in AP (BISAP score and the duration of hospital stay. Serum sFlt-1 above 139 pg/mL predicted more severe AP (MSAP + SAP. In the early phase of AP, sFlt-1 is positively associated with the severity of AP and predicts organ failure, in particular kidney failure. Serum sFlt-1 may be a practical way to improve early assessment of AP severity.

A Pilot Study for the Feasibility of F-18 FLT-PET in Locally Advanced Breast Cancer: Comparison with F-18 FDG-PET

International Nuclear Information System (INIS)

Lee, Jai Hyuen; Kim, Euy Nyong; Hong, Il Ki

2008-01-01

The aim of this study was to investigate the feasibility of 3'-[F-18]fluoro-3'-deoxythymidine positron emission tomography(FLT-PET) for the detection of locally advanced breast cancer and to compare the degree of FLT and 2'-deoxy-2'-[F-18]fluoro-d-glucose(FDG) uptake in primary tumor, lymph nodes and other normal organs. The study subjects consisted of 22 female patients (mean age; 42±6 years) with biopsy-confirmed infiltrating ductal carcinoma between Aug 2005 and Nov 2006. We performed conventional imaging workup, FDG-PET and FLT PET/CT. Average tumor size measured by MRI was 7.2±3.4 cm. With visual analysis, Tumor and Lymph node uptakes of FLT and FDG were determined by calculation of standardized uptake value (SUV) and tumor to background (TB) ratio. We compared FLT tumor uptake with FDG tumor uptake. We also investigated the correlation between FLT tumor uptake and FDG tumor uptake and the concordant rate with lymph node uptakes of FLT and FDG. FLT and FDG uptakes of bone marrow and liver were measured to compare the biodistribution of each other. All tumor lesions were visually detected in both FLT-PET and FDG-PET. There was no significant correlation between maximal tumor size by MRI and SUVmax of FLT-PET or FDG-PET (p>0.05). SUVmax and SUV75 (average SUV within volume of interest using 75% isocontour) of FLT-PET were significantly lower than those of FDG-PET in primary tumor (SUVmax; 6.3±5.2 vs 8.3±4.9, p=0.02 / SUV75; 5.3±4.3 vs 6.9 4.2, p=0.02). There is significant moderate correlation between uptake of FLT and FDG in primary tumor (SUVmax; rho=0.450, p=0.04 / SUV75; rho=0.472, p=0.03). But, TB ratio of FLT-PET was higher than that of FDG-PET(11.7±7.7 vs 6.3±3.8, p=0.001). The concordant rate between FLT and FDG uptake of lymph node was reasonably good (33/34). The FLT SUVs of liver and bone marrow were 4.2±1.2 and 8.3±4.9. The FDG SUVs of liver and bone marrow were 1.8±0.4 and 1.6±0.4. The uptakes of FLT were lower than those of FDG, but all

Dynamic PET evaluation of elevated FLT level after sorafenib treatment in mice bearing human renal cell carcinoma xenograft.

Science.gov (United States)

Ukon, Naoyuki; Zhao, Songji; Yu, Wenwen; Shimizu, Yoichi; Nishijima, Ken-Ichi; Kubo, Naoki; Kitagawa, Yoshimasa; Tamaki, Nagara; Higashikawa, Kei; Yasui, Hironobu; Kuge, Yuji

2016-12-01

Sorafenib, an oral multikinase inhibitor, has anti-proliferative and anti-angiogenic activities and is therapeutically effective against renal cell carcinoma (RCC). Recently, we have evaluated the tumor responses to sorafenib treatment in a RCC xenograft using [Methyl- 3 H(N)]-3'-fluoro-3'-deoxythythymidine ([ 3 H]FLT). Contrary to our expectation, the FLT level in the tumor significantly increased after the treatment. In this study, to clarify the reason for the elevated FLT level, dynamic 3'-[ 18 F]fluoro-3'-deoxythymidine ([ 18 F]FLT) positron emission tomography (PET) and kinetic studies were performed in mice bearing a RCC xenograft (A498). The A498 xenograft was established in nude mice, and the mice were assigned to the control (n = 5) and treatment (n = 5) groups. The mice in the treatment group were orally given sorafenib (20 mg/kg/day p.o.) once daily for 3 days. Twenty-four hours after the treatment, dynamic [ 18 F]FLT PET was performed by small-animal PET. Three-dimensional regions of interest (ROIs) were manually defined for the tumors. A three-compartment model fitting was carried out to estimate four rate constants using the time activity curve (TAC) in the tumor and the blood clearance rate of [ 18 F]FLT. The dynamic pattern of [ 18 F]FLT levels in the tumor significantly changed after the treatment. The rate constant of [ 18 F]FLT phosphorylation (k 3 ) was significantly higher in the treatment group (0.111 ± 0.027 [1/min]) than in the control group (0.082 ± 0.009 [1/min]). No significant changes were observed in the distribution volume, the ratio of [ 18 F]FLT forward transport (K 1 ) to reverse transport (k 2 ), between the two groups (0.556 ± 0.073 and 0.641 ± 0.052 [mL/g] in the control group). Our dynamic PET studies indicated that the increase in FLT level may be caused by the phosphorylation of FLT in the tumor after the sorafenib treatment in the mice bearing a RCC xenograft. Dynamic PET studies with kinetic

Expression and Purification of Functional Ligand-binding Domains of T1R3 Taste Receptors

Energy Technology Data Exchange (ETDEWEB)

Nie,Y.; Hobbs, J.; Vigues, S.; Olson, W.; Conn, G.; Munger, S.

2006-01-01

Chemosensory receptors, including odor, taste, and vomeronasal receptors, comprise the largest group of G protein-coupled receptors (GPCRs) in the mammalian genome. However, little is known about the molecular determinants that are critical for the detection and discrimination of ligands by most of these receptors. This dearth of understanding is due in part to difficulties in preparing functional receptors suitable for biochemical and biophysical analyses. Here we describe in detail two strategies for the expression and purification of the ligand-binding domain of T1R taste receptors, which are constituents of the sweet and umami taste receptors. These class C GPCRs contain a large extracellular N-terminal domain (NTD) that is the site of interaction with most ligands and that is amenable to expression as a separate polypeptide in heterologous cells. The NTD of mouse T1R3 was expressed as two distinct fusion proteins in Escherichia coli and purified by column chromatography. Spectroscopic analysis of the purified NTD proteins shows them to be properly folded and capable of binding ligands. This methodology should not only facilitate the characterization of T1R ligand interactions but may also be useful for dissecting the function of other class C GPCRs such as the large family of orphan V2R vomeronasal receptors.

sFlt-1 and PlGF kinetics during and after pregnancy in women with suspected or confirmed preeclampsia.

Science.gov (United States)

Saleh, Langeza; van den Meiracker, Anton H; Geensen, Roos; Kaya, Aslihan; van Lennep, Jeanine E Roeters; Duvekot, Johannes J; Verdonk, Koen; Steegers, Eric A P; Russcher, Henk; Danser, Jan A H; Visser, Willy

2017-06-10

To assess the evolution of the sFlt-1/PlGF ratio in women with suspected or with confirmed preeclampsia and to investigate the changes in sFlt-1 and PlGF levels in preeclamptic women after delivery. In this exploratory tertiary referral university centre study, using the Roche Diagnostics Elecsys assay, sFlt-1 and PlGF were determined in two groups of patients. In the first group of 46 patients with suspected or confirmed preeclampsia, sFlt-1 and PlGF were measured at least twice during their pregnancy. Women had singleton pregnancies and a median pregnancy duration of 26 weeks (range 18 - 40 weeks). In the second group, sFlt-1 and PlGF of 26 preeclamptic patients were determined before and after delivery. The median gestational age at inclusion was 29 weeks (16 - 37) and the median days between antepartum measurement and delivery was 2 days (1 - 7). In the first group, 90% of patients with a sFlt-1/PlGF ratio ≤38 at baseline (n = 30), ruling out PE, the sFlt-1/PlGF ratio remained stable for up to 100 days. In 16 patients with a sFlt-1/PlGF ratio >38 and in 10% of those with a sFlt-1/PlGF ratio <38 at baseline the ratio increased further. In the second group, after delivery, sFlt-1 dropped to <1% of its pre-delivery values with a half-life of 1.4 ± 0.3 days, while PlGF dropped to ≈ 30% of its pre-delivery values with a half-life of 3.7 ± 4.3 days. Based on this small cohort, up to 10% of women admitted with suspected or confirmed PE presenting with a sFlt-1/PlGF ratio ≤38 display a rise of this sFlt-1/PlGF ratio in subsequent weeks, implying that repeated determination of the sFlt-1/PlGF ratio is required to reject this condition definitively. Furthermore, the rapid and pronounced decline of sFlt-1 values after delivery in patients with PE/HELLP suggests that sFlt-1, in contrast with PlGF, is almost entirely placenta-derived. This article is protected by copyright. All rights reserved.

18F-FLT uptake kinetics in head and neck squamous cell carcinoma: A PET imaging study

International Nuclear Information System (INIS)

Liu, Dan; Fenwick, John D.; Chalkidou, Anastasia; Landau, David B.; Marsden, Paul K.

2014-01-01

Purpose: To analyze the kinetics of 3 ′ -deoxy-3 ′ -[F-18]-fluorothymidine (18F-FLT) uptake by head and neck squamous cell carcinomas and involved nodes imaged using positron emission tomography (PET). Methods: Two- and three-tissue compartment models were fitted to 12 tumor time-activity-curves (TACs) obtained for 6 structures (tumors or involved nodes) imaged in ten dynamic PET studies of 1 h duration, carried out for five patients. The ability of the models to describe the data was assessed using a runs test, the Akaike information criterion (AIC) and leave-one-out cross-validation. To generate parametric maps the models were also fitted to TACs of individual voxels. Correlations between maps of different parameters were characterized using Pearson'sr coefficient; in particular the phosphorylation rate-constants k 3-2tiss and k 5 of the two- and three-tissue models were studied alongside the flux parameters K FLT-2tiss and K FLT of these models, and standardized uptake values (SUV). A methodology based on expectation-maximization clustering and the Bayesian information criterion (“EM-BIC clustering”) was used to distil the information from noisy parametric images. Results: Fits of two-tissue models 2C3K and 2C4K and three-tissue models 3C5K and 3C6K comprising three, four, five, and six rate-constants, respectively, pass the runs test for 4, 8, 10, and 11 of 12 tumor TACs. The three-tissue models have lower AIC and cross-validation scores for nine of the 12 tumors. Overall the 3C6K model has the lowest AIC and cross-validation scores and its fitted parameter values are of the same orders of magnitude as literature estimates. Maps ofK FLT and K FLT-2tiss are strongly correlated (r = 0.85) and also correlate closely with SUV maps (r = 0.72 for K FLT-2tiss , 0.64 for K FLT ). Phosphorylation rate-constant maps are moderately correlated with flux maps (r = 0.48 for k 3-2tiss vs K FLT-2tiss and r = 0.68 for k 5 vs K FLT ); however, neither phosphorylation

Importância da detecção das mutações no gene FLT3 e no gene NPM1 na leucemia mieloide aguda - Classificação da Organização Mundial de Saúde 2008 Importance of detecting FLT3 and NPM1 gene mutations in acute myeloid leukemia -World Health Organization Classification 2008

Directory of Open Access Journals (Sweden)

Marley Aparecida Licínio

2010-01-01

Full Text Available As leucemias mieloides agudas (LMA constituem um grupo de neoplasias malignas caracterizadas pela proliferação descontrolada de células hematopoéticas, decorrente de mutações que podem ocorrer em diferentes fases da diferenciação de células precursoras mieloides. Em 2008, a Organização Mundial da Saúde (OMS-2008 publicou uma nova classificação para neoplasias do sistema hematopoético e linfoide. De acordo com essa classificação, para um diagnóstico mais preciso e estratificação de prognóstico de pacientes com leucemias mieloides agudas, devem-se pesquisar mutações nos genes FLT3 e NPM1. Sabe-se que a presença de mutações no gene FLT3 é de prognóstico desfavorável e que as mutações no gene NPM1 do tipo A são de prognóstico favorável. Assim, nos países desenvolvidos, a análise das mutações no gene FLT3 e NPM1 tem sido considerada como um fator de prognóstico importante na decisão terapêutica em pacientes com diagnóstico de leucemias mieloides agudas. Considerando essas informações, é de extrema importância a análise das mutações no gene FLT3 (duplicação interna em tandem - DIT - e mutação pontual D835 e no gene NPM1 como marcadores moleculares para o diagnóstico, o prognóstico e a monitoração de doença residual mínima em pacientes com leucemias mieloides agudas.Acute myeloid leukemia (AML is a group of malignancies characterized by uncontrolled proliferation of hematopoietic cells resulting from mutations that occur at different stages in the differentiation of myeloid precursor cells. In 2008, the World Health Organization (WHO-2008 published a new classification for cancers of the hematopoietic and lymphoid system. According to this classification, FLT3 and NPM1 gene mutations should be investigated for a more precise diagnosis and prognostic stratification of AML patients. It is well known that the presence of FLT3 gene mutations is considered an unfavorable prognostic factor and type

In-vivo imaging of cellular proliferation in renal cell carcinoma using 18F-fluorothymidine (FLT) PET

International Nuclear Information System (INIS)

Wong, P.; Lee, S. T.; Eng, J.; Berlangieri, S. U.; Pathmaraj, K.; O'Keefe, G. J.; Lawrentschuk, N.

2009-01-01

Full text:Background: The ability to measure cellular proliferation non-invasively in renal cell carcinoma may allow prediction of tumour aggressiveness and response to therapy. The aim of this study was to evaluate the uptake of 18F-fluorothymidine (FLT) in renal cell carcinoma, and to compare this to 18F-fluorodeoxyglucose (FDG), and to an immunohistochemical measure of cellular proliferation (Ki-67). Methods: Twenty seven patients (16 men, 11 women; age 42-77) with newly diagnosed renal cell carcinoma suitable for resection were prospectively enrolled. All patients had preoperative FLT and FDG PET scans. After surgery tumour was taken for histologic analysis and immunohistochemical staining by Ki-67. Results: The mean SUVmax (maximum standardized uptake value) ± SD for FLT in tumour was 2.53 ± 1.26, compared to normal kidney (2.47 ± 0.34). The mean SUVmax for FDG in tumour was similar to FLT (2.60 ± 1.08). Visual identification of tumour using FLT PET compared to normal kidney was facilitated by the use of a pre-operative contrast enhanced CT scan. There was a significant correlation between FLT uptake and the immunohistochemical marker Ki-67 (r=0.624, p=0.0008) in RCC. Ki-67 labelling index was mean ± SD of 13.3% ± 9.2 (range 2.2% to 36.3%). Conclusion: There is detectable uptake of FLT in primary renal cell carcinoma, which correlates with cellular proliferation as assessed by Ki-67 labelling index. This finding has relevance to the use of FLT PET in molecular imaging studies of renal cell carcinoma biology.

Characterization of children with FLT3-ITD acute myeloid leukemia: a report from the AIEOP AML-2002 study group.

Science.gov (United States)

Manara, E; Basso, G; Zampini, M; Buldini, B; Tregnago, C; Rondelli, R; Masetti, R; Bisio, V; Frison, M; Polato, K; Cazzaniga, G; Menna, G; Fagioli, F; Merli, P; Biondi, A; Pession, A; Locatelli, F; Pigazzi, M

2017-01-01

Recurrent molecular markers have been routinely used in acute myeloid leukemia (AML) for risk assessment at diagnosis, whereas their post-induction monitoring still represents a debated issue. We evaluated the prognostic value and biological impact of minimal residual disease (MRD) and of the allelic ratio (AR) of FLT3-internal-tandem duplication (ITD) in childhood AML. We retrospectively screened 494 children with de novo AML for FLT3-ITD mutation, identifying 54 harboring the mutation; 51% of them presented high ITD-AR at diagnosis and had worse event-free survival (EFS, 19.2 versus 63.5% for low ITD-AR, <0.05). Forty-one percent of children with high levels of MRD after the 1st induction course, measured by a patient-specific real-time-PCR, had worse EFS (22.2 versus 59.4% in low-MRD patients, P<0.05). Next, we correlated these parameters with gene expression, showing that patients with high ITD-AR or persistent MRD had characteristic expression profiles with deregulated genes involved in methylation and acetylation. Moreover, patients with high CyclinA1 expression presented an unfavorable EFS (20.3 versus 51.2% in low CyclinA1 group, P<0.01). Our results suggest that ITD-AR levels and molecular MRD should be considered in planning clinical management of FLT3-ITD patients. Different transcriptional activation of epigenetic and oncogenic profiles may explain variability in outcome among these patients, for whom novel therapeutic approaches are desirable.

Monitoring of anti-cancer treatment with (18)F-FDG and (18)F-FLT PET

DEFF Research Database (Denmark)

Jensen, Mette Munk; Kjaer, Andreas

2015-01-01

treatment effect early in a treatment course and by that to stratify patients into responders and non-responders. With 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) and 3'-deoxy-3'-[(18)F]fluorothymidine((18)F-FLT) two of the cancer hallmarks, altered energy metabolism and increased cell proliferation, can......Functional imaging of solid tumors with positron emission tomography (PET) imaging is an evolving field with continuous development of new PET tracers and discovery of new applications for already implemented PET tracers. During treatment of cancer patients, a general challenge is to measure...... be visualized and quantified non-invasively by PET. With (18)F-FDG and (18)F-FLT PET changes in energy metabolism and cell proliferation can thereby be determined after initiation of cancer treatment in both clinical and pre-clinical studies in order to predict, at an early time-point, treatment response...

Crystallization of bi-functional ligand protein complexes.

Science.gov (United States)

Antoni, Claudia; Vera, Laura; Devel, Laurent; Catalani, Maria Pia; Czarny, Bertrand; Cassar-Lajeunesse, Evelyn; Nuti, Elisa; Rossello, Armando; Dive, Vincent; Stura, Enrico Adriano

2013-06-01

Homodimerization is important in signal transduction and can play a crucial role in many other biological systems. To obtaining structural information for the design of molecules able to control the signalization pathways, the proteins involved will have to be crystallized in complex with ligands that induce dimerization. Bi-functional drugs have been generated by linking two ligands together chemically and the relative crystallizability of complexes with mono-functional and bi-functional ligands has been evaluated. There are problems associated with crystallization with such ligands, but overall, the advantages appear to be greater than the drawbacks. The study involves two matrix metalloproteinases, MMP-12 and MMP-9. Using flexible and rigid linkers we show that it is possible to control the crystal packing and that by changing the ligand-enzyme stoichiometric ratio, one can toggle between having one bi-functional ligand binding to two enzymes and having the same ligand bound to each enzyme. The nature of linker and its point of attachment on the ligand can be varied to aid crystallization, and such variations can also provide valuable structural information about the interactions made by the linker with the protein. We report here the crystallization and structure determination of seven ligand-dimerized complexes. These results suggest that the use of bi-functional drugs can be extended beyond the realm of protein dimerization to include all drug design projects. Copyright © 2013 Elsevier Inc. All rights reserved.

Rapid Exercise-Induced Mobilization of Dendritic Cells Is Potentially Mediated by a Flt3L- and MMP-9-Dependent Process in Multiple Sclerosis

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Nathalie Deckx

2015-01-01

Full Text Available In healthy individuals, one exercise bout induces a substantial increase in the number of circulating leukocytes, while their function is transiently suppressed. The effect of one exercise bout in multiple sclerosis (MS is less studied. Since recent evidence suggests a role of dendritic cells (DC in the pathogenesis of MS, we investigated the effect of one combined endurance/resistance exercise bout on the number and function of DC in MS patients and healthy controls. Our results show a rapid increase in the number of DC in response to physical exercise in both MS patients and controls. Further investigation revealed that in particular DC expressing the migratory molecules CCR5 and CD62L were increased upon acute physical activity. This may be mediated by Flt3L- and MMP-9-dependent mobilization of DC, as demonstrated by increased circulating levels of Flt3L and MMP-9 following one exercise bout. Circulating DC display reduced TLR responsiveness after acute exercise, as evidenced by a less pronounced upregulation of activation markers, HLA-DR and CD86, on plasmacytoid DC and conventional DC, respectively. Our results indicate mobilization of DC, which may be less prone to drive inflammatory processes, following exercise. This may present a negative feedback mechanism for exercise-induced tissue damage and inflammation.

Performance of FLT-PET for pulmonary lesion diagnosis compared with traditional FDG-PET: A meta-analysis

Energy Technology Data Exchange (ETDEWEB)

Wang, Zixing; Wang, Yuyan [Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, 100005 (China); Sui, Xin; Zhang, Wei [Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, 100005 (China); Shi, Ruihong [National Institutes for Food and Drug Control, Beijing, 100000 (China); Zhang, Yingqiang; Dang, Yonghong; Qiao, Zhen [Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, 100005 (China); Zhang, Biao [Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, 100005 (China); Song, Wei, E-mail: cjr.songwei@vip.163.com [Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, 100005 (China); Jiang, Jingmei, E-mail: jingmeijiang238@hotmail.com [Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, 100005 (China)

2015-07-15

Highlights: • FDG PET is more sensitive compared with FLT for detecting small and early staged lung cancers. • FLT can reduce false positives of FDG for inflammation-based lesions such as tuberculosis. • FLT shows comparable accuracies for diagnoses of late stage tumors and larger pulmonary lesions. - Abstract: Purpose: Widely used {sup 18}F 2′-deoxy-2′-fluoro-D-glucose (FDG) positron emission tomography (PET) can be problematic with false positives in cancer imaging. This study aims to investigate the diagnostic accuracy of a candidate PET tracer, {sup 18}F 2′,3′-dideoxy-3′-fluoro-2-thiothymidine (FLT), in diagnosing pulmonary lesions compared with FDG. Materials and methods: After comprehensive search and study selection, a meta-analysis was performed on data from 548 patients pooled from 17 studies for evaluating FLT accuracy, in which data from 351 patients pooled from ten double-tracer studies was used for direct comparison with FDG. Weighted sensitivity and specificity were used as main indicators of test performance. Individual data was extracted and patient subgroup analyses were performed. Results: Overall, direct comparisons showed lower sensitivity (0.80 vs. 0.89) yet higher specificity (0.82 vs. 0.66) for FLT compared with FDG (both p < 0.01). Patient subgroup analysis showed FLT was less sensitive than FDG in detecting lung cancers staged as T1 or T2, and those ≤2.0 cm in diameter (0.81 vs. 0.93, and 0.53 vs. 0.78, respectively, both p < 0.05), but was comparable for cancers staged as T3 or T4, and those >2.0 cm in diameter (0.95 vs. 1.00, 0.96 vs. 0.88, both p > 0.05). For benignities, FLT performed better compared with FDG in ruling out inflammation-based lesions (0.57 vs. 0.32, p < 0.05), and demonstrated greater specificity regardless of lesion sizes. Conclusions: Although FLT cannot replace FDG in detecting small and early lung cancers, it may help to prevent patients with larger or inflammatory lesions from cancer misdiagnosis

Low-molecular weight heparin increases circulating sFlt-1 levels and enhances urinary elimination.

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Henning Hagmann

Full Text Available RATIONALE: Preeclampsia is a devastating medical complication of pregnancy which leads to maternal and fetal morbidity and mortality. While the etiology of preeclampsia is unclear, human and animal studies suggest that excessive circulating levels of soluble fms-like tyrosine-kinase-1 (sFlt-1, an alternatively spliced variant of VEGF-receptor1, contribute to the signs and symptoms of preeclampsia. Since sFlt-1 binds to heparin and heparan sulfate proteoglycans, we hypothesized that the anticoagulant heparin, which is often used in pregnancy, may interfere with the levels, distribution and elimination of sFlt-1 in vivo. OBJECTIVE: We systematically determined serum and urine levels of angiogenic factors in preeclamptic women before and after administration of low molecular weight heparin and further characterized the interaction with heparin in biochemical studies. METHODS AND RESULTS: Serum and urine samples were used to measure sFlt-1 levels before and after heparin administration. Serum levels of sFlt-1 increased by 25% after heparin administration in pregnant women. The magnitude of the increase in circulating sFlt-1 correlated with initial sFlt-1 serum levels. Urinary sFlt-1 levels were also elevated following heparin administration and levels of elimination were dependent on the underlying integrity of the glomerular filtration barrier. Biochemical binding studies employing cation exchange chromatography revealed that heparin bound sFlt-1 had decreased affinity to negatively charged surfaces when compared to sFlt-1 alone. CONCLUSION: Low molecular weight heparin administration increased circulating sFlt1 levels and enhanced renal elimination. We provide evidence that both effects may be due to heparin binding to sFlt1 and masking the positive charges on sFlt1 protein.

Enhancing SHP-1 expression with 5-azacytidine may inhibit STAT3 activation and confer sensitivity in lestaurtinib (CEP-701)-resistant FLT3-ITD positive acute myeloid leukemia

International Nuclear Information System (INIS)

Al-Jamal, Hamid Ali Nagi; Mat Jusoh, Siti Asmaa; Hassan, Rosline; Johan, Muhammad Farid

2015-01-01

Tumor-suppressor genes are inactivated by methylation in several cancers including acute myeloid leukemia (AML). Src homology-2 (SH2)-containing protein-tyrosine phosphatase 1 (SHP-1) is a negative regulator of the JAK/STAT pathway. Transcriptional silencing of SHP-1 plays a critical role in the development and progression of cancers through STAT3 activation. 5-Azacytidine (5-Aza) is a DNA methyltransferase inhibitor that causes DNA demethylation resulting in re-expression of silenced SHP-1. Lestaurtinib (CEP-701) is a multi-targeted tyrosine kinase inhibitor that potently inhibits FLT3 tyrosine kinase and induces hematological remission in AML patients harboring the internal tandem duplication of the FLT3 gene (FLT3-ITD). However, the majority of patients in clinical trials developed resistance to CEP-701. Therefore, the aim of this study, was to assess the effect of re-expression of SHP-1 on sensitivity to CEP-701 in resistant AML cells. Resistant cells harboring the FLT3-ITD were developed by overexposure of MV4-11 to CEP-701, and the effects of 5-Aza treatment were investigated. Apoptosis and cytotoxicity of CEP-701 were determined using Annexin V and MTS assays, respectively. Gene expression was performed by quantitative real-time PCR. STATs activity was examined by western blotting and the methylation profile of SHP-1 was studied using MS-PCR and pyrosequencing analysis. Repeated-measures ANOVA and Kruskal–Wallis tests were used for statistical analysis. The cytotoxic dose of CEP-701 on resistant cells was significantly higher in comparison with parental and MV4-11R-cep + 5-Aza cells (p = 0.004). The resistant cells showed a significant higher viability and lower apoptosis compared with other cells (p < 0.001). Expression of SHP-1 was 7-fold higher in MV4-11R-cep + 5-Aza cells compared to parental and resistant cells (p = 0.011). STAT3 was activated in resistant cells. Methylation of SHP-1 was significantly decreased in MV4-11R-cep + 5-Aza cells (p = 0

Andrographolide Suppresses MV4-11 Cell Proliferation through the Inhibition of FLT3 Signaling, Fatty Acid Synthesis and Cellular Iron Uptake

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Xiao Chen

2017-08-01

Full Text Available Background: Andrographolide (ADR, the main active component of Andrographis paniculata, displays anticancer activity in various cancer cell lines, among which leukemia cell lines exhibit the highest sensitivity to ADR. In particular, ADR was also reported to have reduced drug resistance in multidrug resistant cell lines. However, the mechanism of action (MOA of ADR’s anticancer and anti-drug-resistance activities remain elusive. Methods: In this study, we used the MV4-11 cell line, a FLT3 positive acute myeloid leukemia (AML cell line that displays multidrug resistance, as our experimental system. We first evaluated the effect of ADR on MV4-11 cell proliferation. Then, a quantitative proteomics approach was applied to identify differentially expressed proteins in ADR-treated MV4-11 cells. Finally, cellular processes and signal pathways affected by ADR in MV4-11 cell were predicted with proteomic analysis and validated with in vitro assays. Results: ADR inhibits MV4-11 cell proliferation in a dose- and time-dependent manner. With a proteomic approach, we discovered that ADR inhibited fatty acid synthesis, cellular iron uptake and FLT3 signaling pathway in MV4-11 cells. Conclusions: ADR inhibits MV4-11 cell proliferation through inhibition of fatty acid synthesis, iron uptake and protein synthesis. Furthermore, ADR reduces drug resistance by blocking FLT3 signaling.

Distribution Atlas of Proliferating Bone Marrow in Non-Small Cell Lung Cancer Patients Measured by FLT-PET/CT Imaging, With Potential Applicability in Radiation Therapy Planning

International Nuclear Information System (INIS)

Campbell, Belinda A.; Callahan, Jason; Bressel, Mathias; Simoens, Nathalie; Everitt, Sarah; Hofman, Michael S.; Hicks, Rodney J.; Burbury, Kate; MacManus, Michael

2015-01-01

Purpose: Proliferating bone marrow is exquisitely sensitive to ionizing radiation. Knowledge of its distribution could improve radiation therapy planning to minimize unnecessary marrow exposure and avoid consequential prolonged myelosuppression. [18F]-Fluoro-3-deoxy-3-L-fluorothymidine (FLT)–positron emission tomography (PET) is a novel imaging modality that provides detailed quantitative images of proliferating tissues, including bone marrow. We used FLT-PET imaging in cancer patients to produce an atlas of marrow distribution with potential clinical utility. Methods and Materials: The FLT-PET and fused CT scans of eligible patients with non-small cell lung cancer (no distant metastases, no prior cytotoxic exposure, no hematologic disorders) were reviewed. The proportions of skeletal FLT activity in 10 predefined bony regions were determined and compared according to age, sex, and recent smoking status. Results: Fifty-one patients were studied: 67% male; median age 68 (range, 31-87) years; 8% never smokers; 70% no smoking in the preceding 3 months. Significant differences in marrow distribution occurred between sex and age groups. No effect was detected from smoking in the preceding 3 months. Using the mean percentages of FLT uptake per body region, we created an atlas of the distribution of functional bone marrow in 4 subgroups defined by sex and age. Conclusions: This atlas has potential utility for estimating the distribution of active marrow in adult cancer patients to guide radiation therapy planning. However, because of interindividual variation it should be used with caution when radiation therapy risks ablating large proportions of active marrow; in such cases, individual FLT-PET scans may be required

Distribution Atlas of Proliferating Bone Marrow in Non-Small Cell Lung Cancer Patients Measured by FLT-PET/CT Imaging, With Potential Applicability in Radiation Therapy Planning

Energy Technology Data Exchange (ETDEWEB)

Campbell, Belinda A., E-mail: Belinda.Campbell@petermac.org [Department of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia); Callahan, Jason [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia); Bressel, Mathias [Centre for Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, East Melbourne (Australia); Simoens, Nathalie [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia); Everitt, Sarah [Radiotherapy Services, Peter MacCallum Cancer Centre, East Melbourne (Australia); Hofman, Michael S.; Hicks, Rodney J. [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia); Burbury, Kate [Department of Haematology, Peter MacCallum Cancer Centre, East Melbourne (Australia); MacManus, Michael [Department of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne (Australia)

2015-08-01

Purpose: Proliferating bone marrow is exquisitely sensitive to ionizing radiation. Knowledge of its distribution could improve radiation therapy planning to minimize unnecessary marrow exposure and avoid consequential prolonged myelosuppression. [18F]-Fluoro-3-deoxy-3-L-fluorothymidine (FLT)–positron emission tomography (PET) is a novel imaging modality that provides detailed quantitative images of proliferating tissues, including bone marrow. We used FLT-PET imaging in cancer patients to produce an atlas of marrow distribution with potential clinical utility. Methods and Materials: The FLT-PET and fused CT scans of eligible patients with non-small cell lung cancer (no distant metastases, no prior cytotoxic exposure, no hematologic disorders) were reviewed. The proportions of skeletal FLT activity in 10 predefined bony regions were determined and compared according to age, sex, and recent smoking status. Results: Fifty-one patients were studied: 67% male; median age 68 (range, 31-87) years; 8% never smokers; 70% no smoking in the preceding 3 months. Significant differences in marrow distribution occurred between sex and age groups. No effect was detected from smoking in the preceding 3 months. Using the mean percentages of FLT uptake per body region, we created an atlas of the distribution of functional bone marrow in 4 subgroups defined by sex and age. Conclusions: This atlas has potential utility for estimating the distribution of active marrow in adult cancer patients to guide radiation therapy planning. However, because of interindividual variation it should be used with caution when radiation therapy risks ablating large proportions of active marrow; in such cases, individual FLT-PET scans may be required.

Sorafenib promotes graft-versus-leukemia activity in mice and humans through IL-15 production in FLT3-ITD-mutant leukemia cells

NARCIS (Netherlands)

Mathew, N.R.; Baumgartner, F.; Braun, L.; O'Sullivan, D.; Thomas, S.; Waterhouse, M.; Muller, T.A.; Hanke, K.; Taromi, S.; Apostolova, P.; Illert, A.L.; Melchinger, W.; Duquesne, S.; Schmitt-Graeff, A.; Osswald, L.; Yan, K.L.; Weber, A; Tugues, S.; Spath, S.; Pfeifer, D.; Follo, M.; Claus, R.; Lubbert, M.; Rummelt, C.; Bertz, H.; Wasch, R.; Haag, J.; Schmidts, A.; Schultheiss, M.; Bettinger, D.; Thimme, R.; Ullrich, E.; Tanriver, Y.; Vuong, G.L.; Arnold, R.; Hemmati, P.; Wolf, D.; Ditschkowski, M.; Jilg, C.; Wilhelm, K.; Leiber, C.; Gerull, S.; Halter, J.; Lengerke, C.; Pabst, T.; Schroeder, T.; Kobbe, G.; Rosler, W.; Doostkam, S.; Meckel, S.; Stabla, K.; Metzelder, S.K.; Halbach, S.; Brummer, T.; Hu, Z; Dengjel, J.; Hackanson, B.; Schmid, C.; Holtick, U.; Scheid, C.; Spyridonidis, A.; Stolzel, F.; Ordemann, R.; Muller, L.P.; Sicre-de-Fontbrune, F.; Ihorst, G.; Kuball, J.; Ehlert, J.E.; Feger, D.; Wagner, E.M.; Cahn, J.Y.; Schnell, J.; Kuchenbauer, F.; Bunjes, D.; Chakraverty, R.; Richardson, S.; Gill, S.; Kroger, N.; Ayuk, F.; Vago, L.; Ciceri, F.; Muller, A.M.; Kondo, T.; Teshima, T.; Klaeger, S.; Kuster, B.; Kim, D.D.H.; Weisdorf, D.; Velden, W.J. van der; Dorfel, D.; Bethge, W.; Hilgendorf, I.; Hochhaus, A.; Andrieux, G.; Borries, M.; Busch, H.; Magenau, J.; Reddy, P.; Labopin, M.; Antin, J.H., et al.

2018-01-01

Individuals with acute myeloid leukemia (AML) harboring an internal tandem duplication (ITD) in the gene encoding Fms-related tyrosine kinase 3 (FLT3) who relapse after allogeneic hematopoietic cell transplantation (allo-HCT) have a 1-year survival rate below 20%. We observed that sorafenib, a

Interstitial diffusion and the relationship between compartment modelling and multi-scale spatial-temporal modelling of (18)F-FLT tumour uptake dynamics.

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Liu, Dan; Chalkidou, Anastasia; Landau, David B; Marsden, Paul K; Fenwick, John D

2014-09-07

Tumour cell proliferation can be imaged via positron emission tomography of the radiotracer 3'-deoxy-3'-18F-fluorothymidine (18F-FLT). Conceptually, the number of proliferating cells might be expected to correlate more closely with the kinetics of 18F-FLT uptake than with uptake at a fixed time. Radiotracer uptake kinetics are standardly visualized using parametric maps of compartment model fits to time-activity-curves (TACs) of individual voxels. However the relationship between the underlying spatiotemporal accumulation of FLT and the kinetics described by compartment models has not yet been explored. In this work tumour tracer uptake is simulated using a mechanistic spatial-temporal model based on a convection-diffusion-reaction equation solved via the finite difference method. The model describes a chain of processes: the flow of FLT between the spatially heterogeneous tumour vasculature and interstitium; diffusion and convection of FLT within the interstitium; transport of FLT into cells; and intracellular phosphorylation. Using values of model parameters estimated from the biological literature, simulated FLT TACs are generated with shapes and magnitudes similar to those seen clinically. Results show that the kinetics of the spatial-temporal model can be recovered accurately by fitting a 3-tissue compartment model to FLT TACs simulated for those tumours or tumour sub-volumes that can be viewed as approximately closed, for which tracer diffusion throughout the interstitium makes only a small fractional change to the quantity of FLT they contain. For a single PET voxel of width 2.5-5 mm we show that this condition is roughly equivalent to requiring that the relative difference in tracer uptake between the voxel and its neighbours is much less than one.

Covalent Coupling of Nanoparticles with Low-Density Functional Ligands to Surfaces via Click Chemistry

NARCIS (Netherlands)

Rianasari, I.; de Jong, Machiel Pieter; Huskens, Jurriaan; van der Wiel, Wilfred Gerard

2013-01-01

We demonstrate the application of the 1,3-dipolar cycloaddition (“click‿ reaction) to couple gold nanoparticles (Au NPs) functionalized with low densities of functional ligands. The ligand coverage on the citrate-stabilized Au NPs was adjusted by the ligand:Au surface atom ratio, while maintaining

Synthesis of sFlt-1 by platelet-monocyte aggregates contributes to the pathogenesis of preeclampsia

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Major, Heather D.; Cambell, Robert A.; Silver, Robert M.; Branch, D. Ware; Weyrich, Andrew S.

2014-01-01

Objective Soluble fms-like tyrosine kinase (sFlt-1) is an important mediator in the pathogenesis of preeclampsia. We sought to determine if platelet-monocyte aggregates (PMAs) produced sFlt-1 and if PMAs contributed to sFlt-1 production in preeclampsia. Study Design Case-control study of sFlt-1 release from PMAs using blood samples from women with preeclampsia matched by gestational age to pregnant controls. A third group of nonpregnant, reproductive-age women comprised an additional control group. Experiments were also performed using blood from non-pregnant women to elucidate if inducing PMAs could stimulate sFlt-1 production, and if so, to determine the necessary receptors and pathways. Results Women with preeclampsia had increased total Flt-1 concentrations in platelets and monocytes at baseline compared to pregnant controls (25 vs. 10 pg/ml, p=0.0003). sFlt-1 production was elicited from monocytes incubated with thrombin-activated platelets from non-pregnant women. sFlt-1 production was regulated at the transcriptional level by p38 and NF-κB dependent pathways. Conclusion Activated platelets in preeclampsia bind monocytes to generate sFlt-1. PMAs are a previously unrecognized source of sFlt-1 that may contribute to endothelial dysfunction and systemic inflammation commonly observed in preeclampsia. PMID:24440566

Assessment of glucose metabolism and cellular proliferation in multiple myeloma: a first report on combined 18F-FDG and 18F-FLT PET/CT imaging.

Science.gov (United States)

Sachpekidis, C; Goldschmidt, H; Kopka, K; Kopp-Schneider, A; Dimitrakopoulou-Strauss, A

2018-04-10

Despite the significant upgrading in recent years of the role of 18 F-FDG PET/CT in multiple myeloma (MM) diagnostics, there is a still unmet need for myeloma-specific radiotracers. 3'-Deoxy-3'-[ 18 F]fluorothymidine ( 18 F-FLT) is the most studied cellular proliferation PET agent, considered a potentially new myeloma functional imaging tracer. The aim of this pilot study was to evaluate 18 F-FLT PET/CT in imaging of MM patients, in the context of its combined use with 18 F-FDG PET/CT. Eight patients, four suffering from symptomatic MM and four suffering from smoldering MM (SMM), were enrolled in the study. All patients underwent 18 F-FDG PET/CT and 18 F-FLT PET/CT imaging by means of static (whole body) and dynamic PET/CT of the lower abdomen and pelvis (dPET/CT) in two consecutive days. The evaluation of PET/CT studies was based on qualitative evaluation, semi-quantitative (SUV) calculation, and quantitative analysis based on two-tissue compartment modeling. 18 F-FDG PET/CT demonstrated focal, 18 F-FDG avid, MM-indicative bone marrow lesions in five patients. In contrary, 18 F-FLT PET/CT showed focal, 18 F-FLT avid, myeloma-indicative lesions in only two patients. In total, 48 18 F-FDG avid, focal, MM-indicative lesions were detected with 18 F-FDG PET/CT, while 17 18 F-FLT avid, focal, MM-indicative lesions were detected with 18 F-FLT PET/CT. The number of myeloma-indicative lesions was significantly higher for 18 F-FDG PET/CT than for 18 F-FLT PET/CT. A common finding was a mismatch of focally increased 18 F-FDG uptake and reduced 18 F-FLT uptake (lower than the surrounding bone marrow). Moreover, 18 F-FLT PET/CT was characterized by high background activity in the bone marrow compartment, further complicating the evaluation of bone marrow lesions. Semi-quantitative evaluation revealed that both SUV mean and SUV max were significantly higher for 18 F-FLT than for 18 F-FDG in both MM lesions and reference tissue. SUV values were higher in MM lesions than in

Soluble FLT-1 rules placental destiny.

Science.gov (United States)

Yamashita, Michiko; Kumasawa, Keiichi; Nakamura, Hitomi; Kimura, Tadashi

2018-02-19

Placenta previa is an abnormality in which the placenta covers the internal uterine os, and it can cause serious morbidity and mortality in both mother and fetus due to catastrophic hemorrhage. Some pregnant women recover from placenta previa due to a phenomenon called "migration." However, the mechanism of "migration" of the placenta has not been elucidated. Human placentas were collected from patients with placenta previa and those with no abnormal placentation (control). A microarray analysis was performed to detect the genes up- or down-regulated only in the caudal part in the previa group. Specific mRNA expression was evaluated using real-time quantitative reverse transcription PCR (qRT-PCR). Unilateral uterine artery ablation of 8.5 dpc mice was performed to reproduce the reduction of placental blood supply, and weights of the placentas and fetuses were evaluated in 18.5 dpc. Specific mRNA expression was also evaluated in mice placentas. According to the result of the microarray analysis, we focused on soluble fms-like tyrosine kinase-1 (sFLT-1) and hypoxia-inducible factor-1 (HIF-1) alpha. The sFLT-1 expression level is locally high in the caudal part of the human placenta in patients with placenta previa. In mice experiments, the weights of the placentas and fetuses were significantly smaller in the ablation side than those in the control side, and the sFlt-1 expression level was significantly higher in the ablation side than in the control side. Our study suggests that "migration" of the placenta is derived from placental degeneration at the caudal part of the placenta, and sFlt-1 plays a role in this placental degeneration. Copyright © 2018 Elsevier Inc. All rights reserved.

Evaluation of an automated double-synthesis module: efficiency and reliability of subsequent radiosyntheses of FHBG and FLT

International Nuclear Information System (INIS)

Niedermoser, Sabrina; Pape, Manuela; Gildehaus, Franz Josef; Wängler, Carmen; Hartenbach, Markus; Schirrmacher, Ralf; Bartenstein, Peter; Wängler, Björn

2012-01-01

We optimized the synthesis methods for 3′-deoxy-3′-[ 18 F]fluorothymidine ([ 18 F]FLT) and 9-(4-[ 18 F]fluoro-3-[hydroxymethyl]butyl)guanine) ([ 18 F]FHBG) and automated them on an Explora General Nucleophilic double-synthesis module. Furthermore, the synthesis efficiency and reliability and the formation of cross-contaminations of the products when preparing two consecutive batches were evaluated. Whereas the preinstalled FLT synthesis conditions required substantial modification in reaction and neutralization conditions to achieve radiochemical yields of up to 60% within 70±10 min including high-performance liquid chromatography purification, the synthesis of FHBG had to be implemented to the module to obtain competitive radiochemical yields of up to 40% in an overall synthesis time of 60±10 min. The radiochemical purities obtained were ≥99% and ≥96% for the synthesis of [ 18 F]FLT and [ 18 F]FHBG, respectively. No significant changes in yield or purity could be observed between both batch productions. We found that the yields and purities also did not change when performing FLT after FHBG syntheses and vice versa. Hence, we developed a synthesis setup that offers the opportunity to perform two subsequent syntheses of either [ 18 F]FLT, [ 18 F]FHBG or [ 18 F]FLT after [ 18 F]FHBG without decrease in radiochemical yields and purities. Also, no cross-contaminations were observed, which can be attributed to the use of separate product delivery tubes, purification columns and an automated intermediate cleaning program. These results open up the possibility of producing consecutively either two equal 18 F-fluorinated tracers or two different ones in high yields on the same synthesis module.

PU.1 is essential for CD11c expression in CD8(+/CD8(- lymphoid and monocyte-derived dendritic cells during GM-CSF or FLT3L-induced differentiation.

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Xue-Jun Zhu

Full Text Available Dendritic cells (DCs regulate innate and acquired immunity through their roles as antigen-presenting cells. Specific subsets of mature DCs, including monocyte-derived and lymphoid-derived DCs, can be distinguished based on distinct immunophenotypes and functional properties. The leukocyte integrin, CD11c, is considered a specific marker for DCs and it is expressed by all DC subsets. We created a strain of mice in which DCs and their progenitors could be lineage traced based on activity of the CD11c proximal promoter. Surprisingly, we observed levels of CD11c promoter activity that were similar in DCs and in other mature leukocytes, including monocytes, granulocytes, and lymphocytes. We sought to identify DNA elements and transcription factors that regulate DC-associated expression of CD11c. The ets transcription factor, PU.1, is a key regulator of DC development, and expression of PU.1 varies in different DC subsets. GM-CSF increased monocyte-derived DCs in mice and from mouse bone marrow cultured in vitro, but it did not increase CD8(+ lymphoid-derived DCs or B220(+ plasmacytoid DCs. FLT3L increased both monocyte-derived DCs and lymphoid-derived DCs from mouse bone marrow cultured in vitro. GM-CSF increased the 5.3 Kb CD11c proximal promoter activity in monocyte-derived DCs and CD8(+ lymphoid-derived DCs, but not in B220(+ plasmacytoid DCs. In contrast, FLT3L increased the CD11c proximal promoter activity in both monocyte-derived DCs and B220(+ plasmacytoid DCs. We used shRNA gene knockdown and chromatin immunoprecipitation to demonstrate that PU.1 is required for the effects of GM-CSF or FLT3L on monocyte-derived DCs. We conclude that both GM-CSF and FLT3L act through PU.1 to activate the 5.3 Kb CD11c proximal promoter in DCs and to induce differentiation of monocyte-derived DCs. We also confirm that the CD11c proximal promoter is not sufficient to direct lineage specificity of CD11c expression, and that additional DNA elements are required

Circulating Levels of sFlt1 Splice Variants as Predictive Markers for the Development of Preeclampsia

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Colby A. Souders

2015-06-01

Full Text Available Angiogenic biomarkers, including soluble fms-like tyrosine kinase 1 (sFlt1, are thought to be predictors of preeclampsia onset; however, improvement is needed before a widespread diagnostic test can be utilized. Here we describe the development and use of diagnostic monoclonal antibodies specific to the two main splice variants of sFlt1, sFlt1-1 and sFlt1-14. These antibodies were selected for their sensitivity and specificity to their respective sFlt1 isoform in a capture ELISA format. Data from this pilot study suggest that sFlt1-1 may be more predictive of preeclampsia than total sFlt1. It may be possible to improve current diagnostic platforms if more specific antibodies are utilized.

Full-length human placental sFlt-1-e15a isoform induces distinct maternal phenotypes of preeclampsia in mice.

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Gabor Szalai

Full Text Available Most anti-angiogenic preeclampsia models in rodents utilized the overexpression of a truncated soluble fms-like tyrosine kinase-1 (sFlt-1 not expressed in any species. Other limitations of mouse preeclampsia models included stressful blood pressure measurements and the lack of postpartum monitoring. We aimed to 1 develop a mouse model of preeclampsia by administering the most abundant human placental sFlt-1 isoform (hsFlt-1-e15a in preeclampsia; 2 determine blood pressures in non-stressed conditions; and 3 develop a survival surgery that enables the collection of fetuses and placentas and postpartum (PP monitoring.Pregnancy status of CD-1 mice was evaluated with high-frequency ultrasound on gestational days (GD 6 and 7. Telemetry catheters were implanted in the carotid artery on GD7, and their positions were verified by ultrasound on GD13. Mice were injected through tail-vein with adenoviruses expressing hsFlt-1-e15a (n = 11 or green fluorescent protein (GFP; n = 9 on GD8/GD11. Placentas and pups were delivered by cesarean section on GD18 allowing PP monitoring. Urine samples were collected with cystocentesis on GD6/GD7, GD13, GD18, and PPD8, and albumin/creatinine ratios were determined. GFP and hsFlt-1-e15a expression profiles were determined by qRT-PCR. Aortic ring assays were performed to assess the effect of hsFlt-1-e15a on endothelia.Ultrasound predicted pregnancy on GD7 in 97% of cases. Cesarean section survival rate was 100%. Mean arterial blood pressure was higher in hsFlt-1-e15a-treated than in GFP-treated mice (∆MAP = 13.2 mmHg, p = 0.00107; GD18. Focal glomerular changes were found in hsFlt-1-e15a -treated mice, which had higher urine albumin/creatinine ratios than controls (109.3 ± 51.7 μg/mg vs. 19.3 ± 5.6 μg/mg, p = 4.4 x 10(-2; GD18. Aortic ring assays showed a 46% lesser microvessel outgrowth in hsFlt-1-e15a-treated than in GFP-treated mice (p = 1.2 x 10(-2. Placental and fetal weights did not differ between the groups

Full-Length Human Placental sFlt-1-e15a Isoform Induces Distinct Maternal Phenotypes of Preeclampsia in Mice

Science.gov (United States)

Szalai, Gabor; Romero, Roberto; Chaiworapongsa, Tinnakorn; Xu, Yi; Wang, Bing; Ahn, Hyunyoung; Xu, Zhonghui; Chiang, Po Jen; Sundell, Birgitta; Wang, Rona; Jiang, Yang; Plazyo, Olesya; Olive, Mary; Tarca, Adi L.; Dong, Zhong; Qureshi, Faisal; Papp, Zoltan; Hassan, Sonia S.; Hernandez-Andrade, Edgar; Than, Nandor Gabor

2015-01-01

Objective Most anti-angiogenic preeclampsia models in rodents utilized the overexpression of a truncated soluble fms-like tyrosine kinase-1 (sFlt-1) not expressed in any species. Other limitations of mouse preeclampsia models included stressful blood pressure measurements and the lack of postpartum monitoring. We aimed to 1) develop a mouse model of preeclampsia by administering the most abundant human placental sFlt-1 isoform (hsFlt-1-e15a) in preeclampsia; 2) determine blood pressures in non-stressed conditions; and 3) develop a survival surgery that enables the collection of fetuses and placentas and postpartum (PP) monitoring. Methods Pregnancy status of CD-1 mice was evaluated with high-frequency ultrasound on gestational days (GD) 6 and 7. Telemetry catheters were implanted in the carotid artery on GD7, and their positions were verified by ultrasound on GD13. Mice were injected through tail-vein with adenoviruses expressing hsFlt-1-e15a (n = 11) or green fluorescent protein (GFP; n = 9) on GD8/GD11. Placentas and pups were delivered by cesarean section on GD18 allowing PP monitoring. Urine samples were collected with cystocentesis on GD6/GD7, GD13, GD18, and PPD8, and albumin/creatinine ratios were determined. GFP and hsFlt-1-e15a expression profiles were determined by qRT-PCR. Aortic ring assays were performed to assess the effect of hsFlt-1-e15a on endothelia. Results Ultrasound predicted pregnancy on GD7 in 97% of cases. Cesarean section survival rate was 100%. Mean arterial blood pressure was higher in hsFlt-1-e15a-treated than in GFP-treated mice (∆MAP = 13.2 mmHg, p = 0.00107; GD18). Focal glomerular changes were found in hsFlt-1-e15a -treated mice, which had higher urine albumin/creatinine ratios than controls (109.3±51.7μg/mg vs. 19.3±5.6μg/mg, p = 4.4x10-2; GD18). Aortic ring assays showed a 46% lesser microvessel outgrowth in hsFlt-1-e15a-treated than in GFP-treated mice (p = 1.2x10-2). Placental and fetal weights did not differ between the

High radiochemical yield synthesis of [18F]FLT from 3'-O-nosylated thymidine and its 3-N-BOC-protected analogue

International Nuclear Information System (INIS)

Yoon, M. K.; Oh, S. J.; Ryu, J. S.; Moon, D. H.

2002-01-01

We synthesized 3'-O-nosylate and its 3-N-BOC-protected thymidine derivatives as two precursors for high radiochemical yield synthesis of [ 18 F]FLT and optimized [ 18 F]fluorination conditions. (5'-O-DMTr-2'-deoxy-3'-O-nosyl-β-D-threo-pentofuranosyl)thymidine and its s 3-N-BOD-protected analogue were prepared with 54% and 28% yield, respectively. After drying of [ 18 F]F-, 3'-O-nosylate(10-30 mg) or its 3-N-BOC-protected(11-34 mg) precursor was added to 500 μl of CH3CN, respectively. The mixtures were heated at 100-130 .deg. C for 5-30 min. For hydrolysis, 250-500 μl 1N HCl at 50 .deg. C for 5 min condition was used and 1.5ml of 2M sodium acetate was used for neutralization. Reaction mixture was purified by HPLC. The optimal [ 18 F]fluorination yield of 3'-O-nosylate precursor was 85±5.4% with 34 mg of precursor and a reaction time of 5 min at 130 .deg. C. For 3-N-BOC-protected analogue, [ 18 F]fluorination yield was 82±5.4% with 34 mg of precursor and a reaction time of 5 min at 110. deg. C. After HPLC purification, overall radiochemical yield using each precursors were 40±5.2% and 42±5.4% and radiochemical purity were 98±0.5% and 97±2.1% for two precursors, respectively. Preparation time was 60±10.5 min including HPLC purification for two precursors. From these two precursors, [ 18 F]FLT can be easily prepared with high radiochemical yield. 3-N-BOC-protected precursor required milder [ 18 F]fluorination conditions than 3'-O-nosylate precursor

FLT-PET for early response evaluation of colorectal cancer patients with liver metastases

DEFF Research Database (Denmark)

Mogensen, Marie Benzon; Loft, Annika; Aznar, Marianne

2017-01-01

BACKGROUND: Fluoro-L-thymidine (FLT) is a positron emission tomography/computed tomography (PET/CT) tracer which reflects proliferative activity in a cancer lesion. The main objective of this prospective explorative study was to evaluate whether FLT-PET can be used for the early evaluation...... standardised uptake values (SUVmax, SUVmean) were measured. After three cycles of chemotherapy, treatment response was assessed by CT scan based on RECIST 1.1. RESULTS: Thirty-nine consecutive patients were included of which 27 were evaluable. Dropout was mainly due to disease complications. Nineteen patients...... between the response according to RECIST and the early changes in FLT uptake measured as SUVmax(p = 0.24). CONCLUSIONS: No correlation was found between early changes in FLT uptake after the first cycle of treatment and the response evaluated from subsequent CT scans. It seems unlikely that FLT-PET can...

Comparison of [18F]FLT and [18F]FDG in in vitro cancer cell uptake and glucose effect

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Soo Jung Lim; Jin-Sook Ryu; Heuiran Lee; Seok Young Kim; Seung Jun Oh; Dae Hyuk Moon

2004-01-01

[18F]FLT is a new radiopharmaceutical for cell proliferation. We compared [18F]FLT and [18F]FDG in in vitro cancer cell uptake and glucose effect. Method: In vitro cancer cell uptake of [18F]FLT was evaluated using SCC7(mouse squamous cell carcinoma). At 24 hours after seeding 1 x 106 cells/well in 6 well plates with RPMI 1640 medium, culture media were changed to medium with glucose free or glucose concentration of 100 mg/dl. Then, [18F]FLT 5 μCi/50 ml was added to each well. After incubation for 30, 60, 90, 120 minutes, cells were washed twice by PBS, and harvested using 0.25% trypsin-EDTA. After centrifugation and counting at gamma counter, cell uptake was calculated by % activity of cellular uptake to total activity of cell and supernatant. For comparison, same tumor cell uptake experiment was performed with [18F]FDG. Results: After incubation with SCC7 cell line for 30, 60, 90, 120 minutes, [18F]FLT showed 1.95%, 2.17%, 2.10% and 2.80% of cell uptake in glucose free media, respectively. The results [18F]FLT uptake in glucose 100 mg/dl media were 1.82%, 1.87%, 1.97%, and 2.94%, respectively. The results of [18F]FDG in glucose free media were 2.50%, 3.47%, 5.04%, and 10.4%, whereas those in glucose 100 mg/dl media were 1.60%, 1.79%, 1.53%, and 1.82%, respectively. Conclusion: In contrast to [18F]FDG, [18F]FLT uptake in cancer cell was not affected by glucose concentration. In physiologic glucose concentration, [18F]FLT uptake in SCC7 cell line was significantly higher than [18F]FDG uptake after 120 minutes incubation. In [18F]FLT PET imaging may not need fasting for preparation before imaging study. (authors)

An Assessment of Early Response to Targeted Therapy via Molecular Imaging: A Pilot Study of 3′-deoxy-3′[(18F]-Fluorothymidine Positron Emission Tomography 18F-FLT PET/CT in Prostate Adenocarcinoma

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Kalevi Kairemo

2017-04-01

Full Text Available Fluorothymidine is a thymidine analog labeled with fluorine-18 fluorothymidine for positron emission tomography (18F-FLT-PET imaging. Thymidine is a nucleic acid that is used to build DNA. Fluorine-18 fluorothymidine (18F-FLT utilizes the same metabolic pathway as does thymidine but has a very low incidence of being incorporated into the DNA (<1%. 18F-FLT-PET could have a role in the evaluation of response to targeted therapy. We present here a pilot study where we investigated cellular metabolism and proliferation in patients with prostate cancer before and after targeted therapy. Seven patients with Stage IV prostate adenocarcinoma, candidates for targeted therapy inhibiting the hepatocyte growth factor/tyrosine-protein kinase Met (HGF/C-MET pathway, were included in this study. The HGF/C-MET pathway is implicated in prostate cancer progression, and an evaluation of the inhibition of this pathway could be valuable. 18F-FLT was performed at baseline and within four weeks post-therapy. Tumor response was assessed semi-quantitatively and using visual response criteria. The range of SUVmax for 18F-FLT at baseline in the prostate varied from 2.5 to 4.2. This study demonstrated that 18F-FLT with positron emission tomography/computerized tomography (18F-FLT PET/CT had only limited applications in the early response evaluation of prostate cancer. 18F-FLT PET/CT may have some utility in the assessment of response in lymph node disease. However, 18F-FLT PET/CT was not found to be useful in the evaluation of the prostate bed, metastatic skeletal disease, and liver disease.

Dinucleotide repeat polymorphism in Fms-like tyrosine kinase-1 (Flt-1 gene is not associated with preeclampsia

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Park So-Yeon

2008-07-01

Full Text Available Abstract Background Preeclampsia is a major cause of maternal and perinatal mortality and morbidity. The etiology of preeclampsia remains unclear. Recently, it was shown that misregulation of fms-like tyrosine kinase-1 (Flt-1 in the peripheral blood mononuclear cells of pregnant women results in over-expression of the soluble splice variant of Flt-1, sFlt-1, producing an additional (extra-placental source of sFlt-1 that can contribute to the etiology of preeclampsia. The aim of this study was to investigate the relationship between preeclampsia and a dinucleotide (threonine-glycine; TGn repeat polymorphism in the 3' non-coding region of the Flt-1 gene. Methods The number of the d(TGn repeats was analyzed in 170 patients with preeclampsia and in 202 normotensive pregnancies. The region containing the dinucleotide repeat polymorphism of the Flt-1 gene was amplified by polymerase chain reaction (PCR from the DNA samples and was analyzed by direct PCR sequencing. Results We found 10 alleles of the dinucleotide repeat polymorphism and designated these as allele*12 (A1 through allele*23 (A12 according to the number of the TG repeats, from 12 to 23. The frequency of the 14-repeat allele (A3 was most abundant (63.82% in preeclampsia and 69.06% in controls, followed by the 21-repeat allele (A10; 28.53% in preeclampsia and 23.76% in controls. There was no significant difference in the allele frequency between patients with preeclampsia and normal controls. The most common genotype in preeclamptic and normotensive pregnancies was heterozygous (TG14/(TG21 (41.76% and homozygous (TG14/(TG14 (45.05%, respectively. However, the genotype frequencies were not significantly different between preeclamptic patients and controls. Conclusion This is the first study to characterize the dinucleotide repeat polymorphism of the Flt-1 gene in patients with preeclampsia. We found no differences in the allele or genotype frequencies between patients with preeclampsia and

O-fucosylation of the notch ligand mDLL1 by POFUT1 is dispensable for ligand function.

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Julia Müller

Full Text Available Fucosylation of Epidermal Growth Factor-like (EGF repeats by protein O-fucosyltransferase 1 (POFUT1 in vertebrates, OFUT1 in Drosophila is pivotal for NOTCH function. In Drosophila OFUT1 also acts as chaperone for Notch independent from its enzymatic activity. NOTCH ligands are also substrates for POFUT1, but in Drosophila OFUT1 is not essential for ligand function. In vertebrates the significance of POFUT1 for ligand function and subcellular localization is unclear. Here, we analyze the importance of O-fucosylation and POFUT1 for the mouse NOTCH ligand Delta-like 1 (DLL1. We show by mass spectral glycoproteomic analyses that DLL1 is O-fucosylated at the consensus motif C²XXXX(S/TC³ (where C² and C³ are the second and third conserved cysteines within the EGF repeats found in EGF repeats 3, 4, 7 and 8. A putative site with only three amino acids between the second cysteine and the hydroxy amino acid within EGF repeat 2 is not modified. DLL1 proteins with mutated O-fucosylation sites reach the cell surface and accumulate intracellularly. Likewise, in presomitic mesoderm cells of POFUT1 deficient embryos DLL1 is present on the cell surface, and in mouse embryonic fibroblasts lacking POFUT1 the same relative amount of overexpressed wild type DLL1 reaches the cell surface as in wild type embryonic fibroblasts. DLL1 expressed in POFUT1 mutant cells can activate NOTCH, indicating that POFUT1 is not required for DLL1 function as a Notch ligand.

Notch-ligand expression by NALT dendritic cells regulates mucosal Th1- and Th2-type responses

International Nuclear Information System (INIS)

Fukuyama, Yoshiko; Tokuhara, Daisuke; Sekine, Shinichi; Kataoka, Kosuke; Markham, Jonathan D.; Irwin, Allyson R.; Moon, Grace H.; Tokuhara, Yuka; Fujihashi, Keiko; Davydova, Julia; Yamamoto, Masato; Gilbert, Rebekah S.; Fujihashi, Kohtaro

2012-01-01

Highlights: ► Nasal Ad-FL effectively up-regulates APC function by CD11c + DCs in mucosal tissues. ► Nasal Ad-FL induces Notch ligand (L)-expressing CD11c + DCs. ► Notch L-expressing DCs support the induction of Th1- and Th2-type cytokine responses. -- Abstract: Our previous studies showed that an adenovirus (Ad) serotype 5 vector expressing Flt3 ligand (Ad-FL) as nasal adjuvant activates CD11c + dendritic cells (DCs) for the enhancement of antigen (Ag)-specific IgA antibody (Ab) responses. In this study, we examined the molecular mechanism for activation of CD11c + DCs and their roles in induction of Ag-specific Th1- and Th2-cell responses. Ad-FL activated CD11c + DCs expressed increased levels of the Notch ligand (L)-expression and specific mRNA. When CD11c + DCs from various mucosal and systemic lymphoid tissues of mice given nasal OVA plus Ad-FL were cultured with CD4 + T cells isolated from non-immunized OVA TCR-transgenic (OT II) mice, significantly increased levels of T cell proliferative responses were noted. Furthermore, Ad-FL activated DCs induced IFN-γ, IL-2 and IL-4 producing CD4 + T cells. Of importance, these APC functions by Ad-FL activated DCs were down-regulated by blocking Notch–Notch-L pathway. These results show that Ad-FL induces CD11c + DCs to the express Notch-ligands and these activated DCs regulate the induction of Ag-specific Th1- and Th2-type cytokine responses.

Neuronal sFlt1 and Vegfaa determine venous sprouting and spinal cord vascularization

DEFF Research Database (Denmark)

Wild, Raphael; Klems, Alina; Takamiya, Masanari

2017-01-01

Formation of organ-specific vasculatures requires cross-talk between developing tissue and specialized endothelial cells. Here we show how developing zebrafish spinal cord neurons coordinate vessel growth through balancing of neuron-derived Vegfaa, with neuronal sFlt1 restricting Vegfaa......-Kdrl mediated angiogenesis at the neurovascular interface. Neuron-specific loss of flt1 or increased neuronal vegfaa expression promotes angiogenesis and peri-neural tube vascular network formation. Combining loss of neuronal flt1 with gain of vegfaa promotes sprout invasion into the neural tube. On loss...... of neuronal flt1, ectopic sprouts emanate from veins involving special angiogenic cell behaviours including nuclear positioning and a molecular signature distinct from primary arterial or secondary venous sprouting. Manipulation of arteriovenous identity or Notch signalling established that ectopic sprouting...

Metabolically active tumour volume segmentation from dynamic [(18)F]FLT PET studies in non-small cell lung cancer.

Science.gov (United States)

Hoyng, Lieke L; Frings, Virginie; Hoekstra, Otto S; Kenny, Laura M; Aboagye, Eric O; Boellaard, Ronald

2015-01-01

Positron emission tomography (PET) with (18)F-3'-deoxy-3'-fluorothymidine ([(18)F]FLT) can be used to assess tumour proliferation. A kinetic-filtering (KF) classification algorithm has been suggested for segmentation of tumours in dynamic [(18)F]FLT PET data. The aim of the present study was to evaluate KF segmentation and its test-retest performance in [(18)F]FLT PET in non-small cell lung cancer (NSCLC) patients. Nine NSCLC patients underwent two 60-min dynamic [(18)F]FLT PET scans within 7 days prior to treatment. Dynamic scans were reconstructed with filtered back projection (FBP) as well as with ordered subsets expectation maximisation (OSEM). Twenty-eight lesions were identified by an experienced physician. Segmentation was performed using KF applied to the dynamic data set and a source-to-background corrected 50% threshold (A50%) was applied to the sum image of the last three frames (45- to 60-min p.i.). Furthermore, several adaptations of KF were tested. Both for KF and A50% test-retest (TRT) variability of metabolically active tumour volume and standard uptake value (SUV) were evaluated. KF performed better on OSEM- than on FBP-reconstructed PET images. The original KF implementation segmented 15 out of 28 lesions, whereas A50% segmented each lesion. Adapted KF versions, however, were able to segment 26 out of 28 lesions. In the best performing adapted versions, metabolically active tumour volume and SUV TRT variability was similar to those of A50%. KF misclassified certain tumour areas as vertebrae or liver tissue, which was shown to be related to heterogeneous [(18)F]FLT uptake areas within the tumour. For [(18)F]FLT PET studies in NSCLC patients, KF and A50% show comparable tumour volume segmentation performance. The KF method needs, however, a site-specific optimisation. The A50% is therefore a good alternative for tumour segmentation in NSCLC [(18)F]FLT PET studies in multicentre studies. Yet, it was observed that KF has the potential to subsegment

Evaluation of 18F-fluorothymidine positron emission tomography ([18F]FLT-PET/CT) methodology in assessing early response to chemotherapy in patients with gastro-oesophageal cancer.

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Sharma, R; Mapelli, P; Hanna, G B; Goldin, R; Power, D; Al-Nahhas, A; Merchant, S; Ramaswami, R; Challapalli, A; Barwick, T; Aboagye, E O

2016-12-01

3'-Deoxy-3'-[ 18 F]fluorothymidine ([ 18 F]FLT) PET has limited utility in abdominal imaging due to high physiological hepatic uptake of a tracer. We evaluated [ 18 F]FLT-PET/CT combined with a temporal-intensity information-based voxel-clustering approach termed kinetic spatial filtering (KSF) to improve tumour visualisation in patients with locally advanced and metastatic gastro-oesophageal cancer and as a marker of early response to chemotherapy. Dynamic [ 18 F]FLT-PET/CT data were collected before and 3 weeks post first cycle of chemotherapy. Changes in tumour [ 18 F]FLT-PET/CT variables were determined. Response was determined on contrast-enhanced CT after three cycles of therapy using RECIST 1.1. Ten patients were included. Following application of the KSF, visual distinction of all oesophageal and/or gastric tumours was observed in [ 18 F]FLT-PET images. Among the nine patients available for response evaluation (RECIST 1.1), three patients had responded (partial response) and six patients were non-responders (stable disease). There was a significant association between Ki-67 and all baseline [ 18 F]FLT-PET parameters. Area under the curve (AUC) from 0 to 1 min was associated with treatment response. The results of this study indicate that application of the KSF allowed accurate visualisation of both primary and metastatic lesions following imaging with the proliferation marker, [ 18 F]FLT-PET/CT. However, [ 18 F]FLT-PET uptake parameters did not correlate with response. Instead, we observe significant changes in tracer delivery following chemotherapy suggesting that further [ 18 F]FLT-PET/CT studies in this tumour type should be undertaken with caution.

Enhance the performance of current scoring functions with the aid of 3D protein-ligand interaction fingerprints.

Science.gov (United States)

Liu, Jie; Su, Minyi; Liu, Zhihai; Li, Jie; Li, Yan; Wang, Renxiao

2017-07-18

In structure-based drug design, binding affinity prediction remains as a challenging goal for current scoring functions. Development of target-biased scoring functions provides a new possibility for tackling this problem, but this approach is also associated with certain technical difficulties. We previously reported the Knowledge-Guided Scoring (KGS) method as an alternative approach (BMC Bioinformatics, 2010, 11, 193-208). The key idea is to compute the binding affinity of a given protein-ligand complex based on the known binding data of an appropriate reference complex, so the error in binding affinity prediction can be reduced effectively. In this study, we have developed an upgraded version, i.e. KGS2, by employing 3D protein-ligand interaction fingerprints in reference selection. KGS2 was evaluated in combination with four scoring functions (X-Score, ChemPLP, ASP, and GoldScore) on five drug targets (HIV-1 protease, carbonic anhydrase 2, beta-secretase 1, beta-trypsin, and checkpoint kinase 1). In the in situ scoring test, considerable improvements were observed in most cases after application of KGS2. Besides, the performance of KGS2 was always better than KGS in all cases. In the more challenging molecular docking test, application of KGS2 also led to improved structure-activity relationship in some cases. KGS2 can be applied as a convenient "add-on" to current scoring functions without the need to re-engineer them, and its application is not limited to certain target proteins as customized scoring functions. As an interpolation method, its accuracy in principle can be improved further with the increasing knowledge of protein-ligand complex structures and binding affinity data. We expect that KGS2 will become a practical tool for enhancing the performance of current scoring functions in binding affinity prediction. The KGS2 software is available upon contacting the authors.

Imaging Cellular Proliferation During Chemo-Radiotherapy: A Pilot Study of Serial 18F-FLT Positron Emission Tomography/Computed Tomography Imaging for Non-Small-Cell Lung Cancer

International Nuclear Information System (INIS)

Everitt, Sarah; Hicks, Rodney J.; Ball, David; Kron, Tomas; Schneider-Kolsky, Michal; Walter, Tania; Binns, David; Mac Manus, Michael

2009-01-01

Purpose: To establish whether 18 F-3'-deoxy-3'-fluoro-L-thymidine ( 18 F-FLT) can monitor changes in cellular proliferation of non-small-cell lung cancer (NSCLC) during radical chemo-radiotherapy (chemo-RT). Methods and Materials: As part of a prospective pilot study, 5 patients with locally advanced NSCLC underwent serial 18 F-FLT positron emission tomography (PET)/computed tomography (CT) scans during treatment. Baseline 18 F-FLT PET/CT scans were compared with routine staging 18 F-FDG PET/CT scans. Two on-treatment 18 F-FLT scans were performed for each patient on Days 2, 8, 15 or 29, providing a range of time points for response assessment. Results: In all 5 patients, baseline lesional uptake of 18 F-FLT on PET/CT corresponded to staging 18 F-FDG PET/CT abnormalities. 18 F-FLT uptake in tumor was observed on five of nine (55%) on-treatment scans, on Days 2, 8 and 29, but not Day 15. A 'flare' of 18 F-FLT uptake in the primary tumor of one case was observed after 2 Gy of radiation (1.22 x baseline). The remaining eight on-treatment scans demonstrated a mean reduction in 18 F-FLT tumor uptake of 0.58 x baseline. A marked reduction of 18 F-FLT uptake in irradiated bone marrow was observed for all cases. This reduction was observed even after only 2 Gy, and all patients demonstrated a complete absence of proliferating marrow after 10 Gy. Conclusions: This proof of concept study indicates that 18 F-FLT uptake can monitor the distinctive biologic responses of epithelial cancers and highly radiosensitive normal tissue changes during radical chemo-RT. Further studies of 18 F-FLT PET/CT imaging during therapy may suggest that this tracer is useful in developing response-adapted RT for NSCLC.

The sFlt-1/PlGF ratio as a predictor for poor pregnancy and neonatal outcomes

Directory of Open Access Journals (Sweden)

Yu-Shan Chang

2017-12-01

Full Text Available Background: Soluble fms-like tyrosine kinase receptor-1 (sFlt-1/placental growth factor (PlGF ratio has been studied extensively as a predictive marker for pre-eclampsia. However, its usefulness for predicting neonatal outcomes remains unknown. This study aimed to evaluate the association of sFlt-1/PlGF ratio with pregnancy outcomes, neonatal morbidities and short-term postnatal growth patterns in pregnant women and their babies. Methods: sFlt-1 and PlGF were measured in women with fetal intrauterine growth retardation (IUGR or pre-eclampsia during gestational age (GA of 16–36 weeks. These women were classified into high- and low-ratio groups with a sFlt-1/PlGF cut-off ratio of 85. The maternal and neonatal outcomes were retrospectively reviewed and compared between the two groups. Results: A total of 25 pregnant women were recruited. Thirteen of them had a sFlt-1/PlGF ratio over 85 and twelve had a ratio of less than 85. The median duration from elevation of sFlt-1/PlGF to delivery was 4.5 weeks. Women in the high SFlt-1/PlGF ratio group had higher rates of intrauterine fetal demise (2/13 vs. 0/12 and early termination (1/13 vs. 0/12. The surviving offspring in this group had a higher incidence of preterm birth (GA: 31.4 ± 2.9 weeks vs. 37.3 ± 1.3 weeks, p < 0.001, lower birth weight (1142 ± 472 g vs. 2311 ± 236 g, p < 0.001, higher incidence of respiratory distress syndrome (6/10 vs. 0/12, p = 0.002 and bronchopulmonary dysplasia (4/10 vs. 0/12, p = 0.01. However, the percentile of body weight, height and head circumference at 28 days of age, 56 days of age and the corrected age of 6 months were comparable between groups. Conclusions: High sFlt-1/PlGF ratio in pregnant women is associated with poor pregnancy and neonatal outcomes. Therefore, the monitoring of sFlt-1/PlGF ratio in pregnant women with fetal IUGR and timely management for placenta-associated diseases are

The role of nucleoside/nucleotide transport and metabolism in the uptake and retention of 3'-fluoro-3'-deoxythymidine in human B-lymphoblast cells

International Nuclear Information System (INIS)

Plotnik, David A.; McLaughlin, Lena J.; Chan, Jenny; Redmayne-Titley, Joshua N.; Schwartz, Jeffrey L.

2011-01-01

Introduction: Recent studies in the human adenocarcinoma cell line A549 have identified cell growth-dependent equilibrative nucleoside transporter-1 (hENT1) as a modifier of 3'-fluoro-3'-deoxythymidine (FLT) uptake and retention. In the present study, we used the ability to isolate human lymphoblastoid clones deficient in thymidine kinase 1 (TK1) to study how metabolism and nucleoside transport influence FLT uptake and retention. Methods: Transport and metabolism of FLT were measured in the human lymphoblastoid cell line TK6 and in eight clones isolated from TK6. Four clones were TK1-proficient, while four were TK1-deficient. Both influx and efflux of FLT were measured under conditions where concentrative and equilibrative transport could be distinguished. Results: Sodium-dependent concentrative FLT transport dominated over equilibrative transport mechanisms and while inhibition of hENT1 reduced FLT uptake, there were no correlations between clonal variations in hENT1 levels and FLT uptake. There was an absolute requirement of TK1 for concentration of FLT in TK6 cells. FLT uptake reached a peak after 60 min of incubation with FLT after which intracellular levels of FLT and FLT metabolites declined. Efflux was rapid and was associated with reductions in FLT and each of its metabolites. Both FLT and FLT-monophosphate were found in the efflux buffer. Conclusions: Initial rates of FLT uptake were a function of both concentrative and equilibrative transporters. TK1 activity was an absolute requirement for the accumulation of FLT. Retention was dependent on nucleoside/nucleotide efflux and retrograde metabolism of FLT nucleotides.

18F-FLT Positron Emission Tomography/Computed Tomography Imaging in Pancreatic Cancer: Determination of Tumor Proliferative Activity and Comparison with Glycolytic Activity as Measured by 18F-FDG Positron Emission Tomography/Computed Tomography Imaging

Directory of Open Access Journals (Sweden)

Senait Aknaw Debebe

2016-02-01

Full Text Available Objective: This phase-I imaging study examined the imaging characteristic of 3’-deoxy-3’-(18F-fluorothymidine (18F-FLT positron emission tomography (PET in patients with pancreatic cancer and comparisons were made with (18F-fluorodeoxyglucose (18F-FDG. The ultimate aim was to develop a molecular imaging tool that could better define the biologic characteristics of pancreas cancer, and to identify the patients who could potentially benefit from surgical resection who were deemed inoperable by conventional means of staging. Methods: Six patients with newly diagnosed pancreatic cancer underwent a combined FLT and FDG computed tomography (CT PET/CT imaging protocol. The FLT PET/CT scan was performed within 1 week of FDG PET/CT imaging. Tumor uptake of a tracer was determined and compared using various techniques; statistical thresholding (z score=2.5, and fixed standardized uptake value (SUV thresholds of 1.4 and 2.5, and applying a threshold of 40% of maximum SUV (SUVmax and mean SUV (SUVmean. The correlation of functional tumor volumes (FTV between 18F-FDG and 18F-FLT was assessed using linear regression analysis. Results: It was found that there is a correlation in FTV due to metabolic and proliferation activity when using a threshold of SUV 2.5 for FDG and 1.4 for FLT (r=0.698, p=ns, but a better correlation was obtained when using SUV of 2.5 for both tracers (r=0.698, p=ns. The z score thresholding (z=2.5 method showed lower correlation between the FTVs (r=0.698, p=ns of FDG and FLT PET. Conclusion: Different tumor segmentation techniques yielded varying degrees of correlation in FTV between FLT and FDGPET images. FLT imaging may have a different meaning in determining tumor biology and prognosis.

Notch-ligand expression by NALT dendritic cells regulates mucosal Th1- and Th2-type responses

Energy Technology Data Exchange (ETDEWEB)

Fukuyama, Yoshiko; Tokuhara, Daisuke [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States); Division of Mucosal Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639 (Japan); Sekine, Shinichi [Department of Preventive Dentistry, Graduate School of Dentistry, Osaka University, Osaka 565-0871 (Japan); Kataoka, Kosuke [Department of Preventive Dentistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8504 (Japan); Markham, Jonathan D.; Irwin, Allyson R.; Moon, Grace H.; Tokuhara, Yuka; Fujihashi, Keiko [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States); Davydova, Julia; Yamamoto, Masato [Department of Surgery, University of Minnesota, Minneapolis, MN 55455 (United States); Gilbert, Rebekah S. [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States); Fujihashi, Kohtaro, E-mail: kohtarof@uab.edu [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States)

2012-02-03

Highlights: Black-Right-Pointing-Pointer Nasal Ad-FL effectively up-regulates APC function by CD11c{sup +} DCs in mucosal tissues. Black-Right-Pointing-Pointer Nasal Ad-FL induces Notch ligand (L)-expressing CD11c{sup +} DCs. Black-Right-Pointing-Pointer Notch L-expressing DCs support the induction of Th1- and Th2-type cytokine responses. -- Abstract: Our previous studies showed that an adenovirus (Ad) serotype 5 vector expressing Flt3 ligand (Ad-FL) as nasal adjuvant activates CD11c{sup +} dendritic cells (DCs) for the enhancement of antigen (Ag)-specific IgA antibody (Ab) responses. In this study, we examined the molecular mechanism for activation of CD11c{sup +} DCs and their roles in induction of Ag-specific Th1- and Th2-cell responses. Ad-FL activated CD11c{sup +} DCs expressed increased levels of the Notch ligand (L)-expression and specific mRNA. When CD11c{sup +} DCs from various mucosal and systemic lymphoid tissues of mice given nasal OVA plus Ad-FL were cultured with CD4{sup +} T cells isolated from non-immunized OVA TCR-transgenic (OT II) mice, significantly increased levels of T cell proliferative responses were noted. Furthermore, Ad-FL activated DCs induced IFN-{gamma}, IL-2 and IL-4 producing CD4{sup +} T cells. Of importance, these APC functions by Ad-FL activated DCs were down-regulated by blocking Notch-Notch-L pathway. These results show that Ad-FL induces CD11c{sup +} DCs to the express Notch-ligands and these activated DCs regulate the induction of Ag-specific Th1- and Th2-type cytokine responses.

Repeatability of quantitative 18F-FLT uptake measurements in solid tumors: an individual patient data multi-center meta-analysis.

Science.gov (United States)

Kramer, G M; Liu, Y; de Langen, A J; Jansma, E P; Trigonis, I; Asselin, M-C; Jackson, A; Kenny, L; Aboagye, E O; Hoekstra, O S; Boellaard, R

2018-06-01

3'-deoxy-3'-[ 18 F]fluorothymidine ( 18 F-FLT) positron emission tomography (PET) provides a non-invasive method to assess cellular proliferation and response to antitumor therapy. Quantitative 18 F-FLT uptake metrics are being used for evaluation of proliferative response in investigational setting, however multi-center repeatability needs to be established. The aim of this study was to determine the repeatability of 18 F-FLT tumor uptake metrics by re-analyzing individual patient data from previously published reports using the same tumor segmentation method and repeatability metrics across cohorts. A systematic search in PubMed, EMBASE.com and the Cochrane Library from inception-October 2016 yielded five 18 F-FLT repeatability cohorts in solid tumors. 18 F-FLT avid lesions were delineated using a 50% isocontour adapted for local background on test and retest scans. SUV max , SUV mean , SUV peak , proliferative volume and total lesion uptake (TLU) were calculated. Repeatability was assessed using the repeatability coefficient (RC = 1.96 × SD of test-retest differences), linear regression analysis, and the intra-class correlation coefficient (ICC). The impact of different lesion selection criteria was also evaluated. Images from four cohorts containing 30 patients with 52 lesions were obtained and analyzed (ten in breast cancer, nine in head and neck squamous cell carcinoma, and 33 in non-small cell lung cancer patients). A good correlation was found between test-retest data for all 18 F-FLT uptake metrics (R 2  ≥ 0.93; ICC ≥ 0.96). Best repeatability was found for SUV peak (RC: 23.1%), without significant differences in RC between different SUV metrics. Repeatability of proliferative volume (RC: 36.0%) and TLU (RC: 36.4%) was worse than SUV. Lesion selection methods based on SUV max  ≥ 4.0 improved the repeatability of volumetric metrics (RC: 26-28%), but did not affect the repeatability of SUV metrics. In multi-center studies

The role of nucleoside/nucleotide transport and metabolism in the uptake and retention of 3'-fluoro-3'-deoxythymidine in human B-lymphoblast cells

Energy Technology Data Exchange (ETDEWEB)

Plotnik, David A.; McLaughlin, Lena J.; Chan, Jenny; Redmayne-Titley, Joshua N.; Schwartz, Jeffrey L., E-mail: jschwart@uw.edu

2011-10-15

Introduction: Recent studies in the human adenocarcinoma cell line A549 have identified cell growth-dependent equilibrative nucleoside transporter-1 (hENT1) as a modifier of 3'-fluoro-3'-deoxythymidine (FLT) uptake and retention. In the present study, we used the ability to isolate human lymphoblastoid clones deficient in thymidine kinase 1 (TK1) to study how metabolism and nucleoside transport influence FLT uptake and retention. Methods: Transport and metabolism of FLT were measured in the human lymphoblastoid cell line TK6 and in eight clones isolated from TK6. Four clones were TK1-proficient, while four were TK1-deficient. Both influx and efflux of FLT were measured under conditions where concentrative and equilibrative transport could be distinguished. Results: Sodium-dependent concentrative FLT transport dominated over equilibrative transport mechanisms and while inhibition of hENT1 reduced FLT uptake, there were no correlations between clonal variations in hENT1 levels and FLT uptake. There was an absolute requirement of TK1 for concentration of FLT in TK6 cells. FLT uptake reached a peak after 60 min of incubation with FLT after which intracellular levels of FLT and FLT metabolites declined. Efflux was rapid and was associated with reductions in FLT and each of its metabolites. Both FLT and FLT-monophosphate were found in the efflux buffer. Conclusions: Initial rates of FLT uptake were a function of both concentrative and equilibrative transporters. TK1 activity was an absolute requirement for the accumulation of FLT. Retention was dependent on nucleoside/nucleotide efflux and retrograde metabolism of FLT nucleotides.

High Level of Soluble FMS-Like Tyrosine Kinase-1 (sFlt-1 Serum in Pregnancy as a Risk Factor of Preeclampsia

Directory of Open Access Journals (Sweden)

I Gede Mega Putra

2016-07-01

Full Text Available Background: Recently, etiology and pathogenesis of preeclampsia remain unknown. One of the theory indicating that hypoxia and ischemic placenta caused by abnormal cytotrophoblast invasion in preeclampsia. Soluble Fms-like tyrosine kinase-1 (sFlt-1 serum as a laboratory marker of hypoxia condition that contributes to the occurrence of endothelial damage and clinical manifestations in preeclampsia. Objective: This study was aimed at proving that high level of soluble Fms-like tyrosine kinase-1 (sFlt-1 serum in pregnancy as a risk factor for preeclampsia. Methods: This study was a case control. Among 58 pregnant women studied, 29 women with preeclampsia as a case group and 29 women with normal pregnancy as a control group. Soluble Fms-like tyrosine kinase-1 (sFlt-1 serum was analyzed in the Prodia Laboratory. Collected data were tested for normality using Kolmogorov-Smirnov, then analyzed with independent sample test. Chi-Square test used to determine soluble Fms-like tyrosine kinase-1 (sFlt-1 serum level in preeclampsia. Results: This research concluded that the average level of soluble Fms-like tyrosine kinase-1 (sFlt-1 serum in preeclampsia were 11231.00 ± 8390.3 pg/mL and 3981.62 ± 4921.5 pg/mL in normal pregnancy. Analysis of significance with independent t-test concluded that the value of t = 4.01 and p = 0.001. This mean the average levels of soluble Fms-like tyrosine kinase-1 (sFlt-1serum levels in both groups were difference significantly (p <0.05. Based on the cut-off point of sFlt-1 serum levels was 4505.50 pg/mL with 79.3% sensitivity and 82.8% specificity, the relative risk of preeclampsia was 18 times (OR = 18.40, IK 95% = 4.93 to 68.70, p = 0.001. Conclusion:  Based on this research, high levels of soluble Fms-like tyrosine kinase-1 (sFlt-1 in pregnancy was proved as a risk factor for preeclampsia.

FLT-PET for early response evaluation of colorectal cancer patients with liver metastases: a prospective study.

Science.gov (United States)

Mogensen, Marie Benzon; Loft, Annika; Aznar, Marianne; Axelsen, Thomas; Vainer, Ben; Osterlind, Kell; Kjaer, Andreas

2017-12-01

Fluoro-L-thymidine (FLT) is a positron emission tomography/computed tomography (PET/CT) tracer which reflects proliferative activity in a cancer lesion. The main objective of this prospective explorative study was to evaluate whether FLT-PET can be used for the early evaluation of treatment response in colorectal cancer patients (CRC) with liver metastases. Patients with metastatic CRC having at least one measurable (>1 cm) liver metastasis receiving first-line chemotherapy were included. A FLT-PET/CT scan was performed at baseline and after the first treatment. The maximum and mean standardised uptake values (SUV max , SUV mean ) were measured. After three cycles of chemotherapy, treatment response was assessed by CT scan based on RECIST 1.1. Thirty-nine consecutive patients were included of which 27 were evaluable. Dropout was mainly due to disease complications. Nineteen patients (70%) had a partial response, seven (26%) had stable disease and one (4%) had progressive disease. A total of 23 patients (85%) had a decrease in FLT uptake following the first treatment. The patient with progressive disease had the highest increase in FLT uptake in SUV max . There was no correlation between the response according to RECIST and the early changes in FLT uptake measured as SUV max (p = 0.24). No correlation was found between early changes in FLT uptake after the first cycle of treatment and the response evaluated from subsequent CT scans. It seems unlikely that FLT-PET can be used on its own for the early response evaluation of metastatic CRC.

Soluble Flt-1 and PlGF: new markers of early pregnancy loss?

LENUS (Irish Health Repository)

Muttukrishna, Shanthi

2012-01-31

Recent data have indicated a relationship between placental oxygen and angiogenic protein levels in the first trimester of normal pregnancies. Our objective was to investigate if maternal serum levels of angiogenic factors Soluble vascular endothelial growth factor (VEGF) receptor 1 (sFlt-1), soluble Endoglin and placental growth factor (PlGF) are altered in women with symptoms of threatened miscarriage (TM) and if they are predictive of a subsequent miscarriage. Blood samples were collected at 6-10 weeks from women presenting with TM (n = 40), from asymptomatic controls (n = 32) and from non- pregnant women in their luteal phase (n = 14). All samples were assayed for serum level of sFLT-1, PlGF, sEndoglin and HSP70 using commercial ELISAs. Samples were analysed retrospectively on the basis of pregnancy outcome. TM group included 21 women with a normal pregnancy outcome and 19 with subsequent complete miscarriage. The latter subgroup had significantly lower mean maternal serum (MS) sFlt-1 (83%, P<0.001) and PlGF (44%, P<0.001) compared to those with a normal pregnancy outcome. Asymptomatic control pregnant women had similar MS levels of sFlt-1 and PlGF compared to the TM patients with a normal outcome. The mean MS sFlt-1 (>10 fold) and MS PlGF ( approximately 2 fold) levels were significantly (P<0.001) higher in control pregnant women compared to the non-pregnant group in the luteal phase of the menstrual cycle. Soluble Endoglin was not altered in the normal pregnant women compared to non pregnant women, although lower in the TM subgroup with a subsequent miscarriage ( approximately 25%, P<0.001) compared to TM with a live birth. There was no significant difference in the mean MS HSP 70 levels between the different groups. This study shows that sFlt1 and PlGF MS levels are increased by several folds in early pregnancy and that MS sFlt-1 and MS PlGF are markedly decreased in threatened miscarriage patients who subsequently have a miscarriage suggesting these

Soluble Flt-1 and PlGF: new markers of early pregnancy loss?

LENUS (Irish Health Repository)

Muttukrishna, Shanthi

2011-01-01

Recent data have indicated a relationship between placental oxygen and angiogenic protein levels in the first trimester of normal pregnancies. Our objective was to investigate if maternal serum levels of angiogenic factors Soluble vascular endothelial growth factor (VEGF) receptor 1 (sFlt-1), soluble Endoglin and placental growth factor (PlGF) are altered in women with symptoms of threatened miscarriage (TM) and if they are predictive of a subsequent miscarriage. Blood samples were collected at 6-10 weeks from women presenting with TM (n = 40), from asymptomatic controls (n = 32) and from non- pregnant women in their luteal phase (n = 14). All samples were assayed for serum level of sFLT-1, PlGF, sEndoglin and HSP70 using commercial ELISAs. Samples were analysed retrospectively on the basis of pregnancy outcome. TM group included 21 women with a normal pregnancy outcome and 19 with subsequent complete miscarriage. The latter subgroup had significantly lower mean maternal serum (MS) sFlt-1 (83%, P<0.001) and PlGF (44%, P<0.001) compared to those with a normal pregnancy outcome. Asymptomatic control pregnant women had similar MS levels of sFlt-1 and PlGF compared to the TM patients with a normal outcome. The mean MS sFlt-1 (>10 fold) and MS PlGF (∼2 fold) levels were significantly (P<0.001) higher in control pregnant women compared to the non-pregnant group in the luteal phase of the menstrual cycle. Soluble Endoglin was not altered in the normal pregnant women compared to non pregnant women, although lower in the TM subgroup with a subsequent miscarriage (∼25%, P<0.001) compared to TM with a live birth. There was no significant difference in the mean MS HSP 70 levels between the different groups. This study shows that sFlt1 and PlGF MS levels are increased by several folds in early pregnancy and that MS sFlt-1 and MS PlGF are markedly decreased in threatened miscarriage patients who subsequently have a miscarriage suggesting these proteins are

Short-term, serum-free, static culture of cord blood-derived CD34+ cells: effects of FLT3-L and MIP-1alpha on in vitro expansion of hematopoietic progenitor cells.

Science.gov (United States)

Capmany, G; Querol, S; Cancelas, J A; García, J

1999-08-01

The use of ex vivo expanded cells has been suggested as a possible means to accelerate the speed of engraftment in cord blood (CB) transplantation. The aim of this study was to fix the optimal condition for the generation of committed progenitors without affecting the stem cell compartment. Analysis of the effects of FLT3-L and MIP-1alpha when combined with SCF, IL-3 and IL-6, in short-term (6 days), serum-free expansion cultures of CB-selected CD34+ cells. An important expansion was obtained that ranged between 8-15 times for CFU-GM, 21-51 times for the BFU-E/CFU-Mix population and 11 to 30 times for CD34+ cells assessed by flow cytometry. From the combinations tested, those in which FLT3-L was present had a significant increase in the expansion of committed progenitors, while the presence of MIP-1alpha had a detrimental effect on the generation of more differentiated cells. However, stem cell candidates assessed by week 5 CAFC assay could be maintained in culture when both MIP-1a and FLT3-L were present (up to 91% recovery). This culture system was also able to expand megakaryocytic precursors as determined by the co-expression of CD34 and CD61 antigens (45-70 times), in spite of the use of cytokines non-specific for the megakaryocytic lineage. The results obtained point to the combination of SCF, IL-3, IL-6, FLT3-L and MIP-1alpha as the best suited for a pre-clinical short-term serum-free static ex vivo expansion protocol of CB CD34+ cells, since it can generate large numbers of committed progenitor cells as well as maintaining week 5 CAFC.

Designer TGFβ superfamily ligands with diversified functionality.

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George P Allendorph

Full Text Available Transforming Growth Factor--beta (TGFβ superfamily ligands, including Activins, Growth and Differentiation Factors (GDFs, and Bone Morphogenetic Proteins (BMPs, are excellent targets for protein-based therapeutics because of their pervasiveness in numerous developmental and cellular processes. We developed a strategy termed RASCH (Random Assembly of Segmental Chimera and Heteromer, to engineer chemically-refoldable TGFβ superfamily ligands with unique signaling properties. One of these engineered ligands, AB208, created from Activin-βA and BMP-2 sequences, exhibits the refolding characteristics of BMP-2 while possessing Activin-like signaling attributes. Further, we find several additional ligands, AB204, AB211, and AB215, which initiate the intracellular Smad1-mediated signaling pathways more strongly than BMP-2 but show no sensitivity to the natural BMP antagonist Noggin unlike natural BMP-2. In another design, incorporation of a short N-terminal segment from BMP-2 was sufficient to enable chemical refolding of BMP-9, without which was never produced nor refolded. Our studies show that the RASCH strategy enables us to expand the functional repertoire of TGFβ superfamily ligands through development of novel chimeric TGFβ ligands with diverse biological and clinical values.

Radiation-induced decrease of CD8+ dendritic cells contributes to Th1/Th2 shift.

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Liu, Hu; Li, Bailong; Jia, Xiaojing; Ma, Yan; Gu, Yifeng; Zhang, Pei; Wei, Qun; Cai, Jianming; Cui, Jianguo; Gao, Fu; Yang, Yanyong

2017-05-01

Exposure to ionizing radiation (IR) often reduce the helper T (Th) 1 like function, resulting in a Th1/Th2 imbalance, which could affect the efficacy of cancer radiotherapy. As the most potent antigen presenting cells, dendritic cells (DC) can be divided into several subsets with specialized function. However, there is no literature covering the changes of DC subsets and their roles in immune regulation in response to IR. In the present study, we were aimed to investigate the changes of DC subsets after IR and its relationship with Th1/Th2 immunity. We found a significant decrease of BDCA3+DC in the blood of patients treated with radiotherapy. CD8+DC, a mouse equivalent of human BDCA3+DC, was also found decreased in mice spleen, peripheral blood and lymph node tissues after irradiation. As CD8+DC mainly induce Th1 immunity, we tested the changes of Th1/Th2 response and found that IR caused a repression of Th1 immunity, indicating a possible role of CD8+DC in radiation-induced Th1/Th2 imbalance. We also found that a CD8+DC-inducing cytokine, Fms-like tyrosine kinase 3 ligand (FLT3 ligand), restored CD8+DC and reversed Th1/Th2 shift. And then we found that bone marrow cells from irradiated mice differentiated into less CD8+DC, which was also protected by FLT3 ligand. In conclusion, our data showed that IR induced a decrease of CD8+DC and Th1/Th2 shift, which was reversed by Flt3 ligand treatment, suggesting a novel mechanism for radiation-induced immunosuppression. Copyright © 2017. Published by Elsevier B.V.

Early Death in Two Patients with Acute Promyelocytic Leukemia Presenting the bcr3 Isoform, FLT3-ITD Mutation, and Elevated WT1 Level

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Marianna Greco

2013-01-01

Full Text Available Despite major advances in the treatment of acute promyelocytic leukemia (APL, the problem of early death (ED remains unsolved. Alongside the currently known clinical and hematological risk factors, prognostic significance has been attributed to internal tandem duplication mutations of the fms-like tyrosine kinase-3 (FLT3-ITD, hypogranular variant morphology, and the bcr-3 isoform of PML-RARα. We describe premature death of two patients with the hypogranular variant of APL who presented remarkably high expression levels of Wilms' tumor gene (WT1. Our results point to WT1 as an important prognostic factor of ED that needs to be promptly evaluated in all newly diagnosed cases of APL.

Early detection of response to experimental chemotherapeutic Top216 with [18F]FLT and [18F]FDG PET in human ovary cancer xenografts in mice

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Jensen, Mette Munk; Erichsen, Kamille Dumong; Björkling, Fredrik

2010-01-01

3'-Deoxy-3'-[(18)F]fluorothymidine ((18)F-FLT) is a tracer used to assess cell proliferation in vivo. The aim of the study was to use (18)F-FLT positron emission tomography (PET) to study treatment responses to a new anti-cancer compound. To do so, we studied early anti-proliferative effects...

Neutralizing VEGF bioactivity with a soluble chimeric VEGF receptor protein flt (1-3) IGG inhibits testosterone stimulated prostate growth in castrated mice

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Hammarsten, P.; Lissbrant, E.; Lissbrant, I.-F.; Haeggstroem-Rudolfsson, S.; Bergh, A.; Ferrara, N.

2003-01-01

Recent studies show that testosterone stimulated growth of the glandular tissue in the ventral prostate in adult castrated rats is preceded by increased epithelial VEGF synthesis, endothelial cell proliferation, vascular growth, and increased blood flow. These observations suggest that testosterone stimulated prostate growth could be angiogenesis dependent, and that VEGF could play a central role in this. To test this hypothesis adult male mice were castrated and after one week treated with testosterone and vehicle, or with testosterone and a soluble chimeric VEGF-receptor flt(1-3)IgG protein. Treatment with testosterone markedly increased endothelial cell proliferation, vascular volume and organ weight in the ventral prostate lobe in the vehicle groups, but these responses were inhibited but not fully prevented by anti-VEGF treatment. The testosterone stimulated increase in epithelial cell proliferation was unaffected by flt(1-3)IgG, but endothelial and epithelial cell apoptosis were increased in the anti-VEGF compared to the vehicle treated group. This study, together with our previous observations, suggest that testosterone stimulates vascular growth in the ventral prostate lobe indirectly by increasing epithelial VEGF synthesis and that this is a necessary component in testosterone stimulated prostate growth

Technical advance: Generation of human pDC equivalents from primary monocytes using Flt3-L and their functional validation under hypoxia.

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Sekar, Divya; Brüne, Bernhard; Weigert, Andreas

2010-08-01

The division of labor between DC subsets is evolutionarily well-defined. mDC are efficient in antigen presentation, whereas pDC act as rheostats of the immune system. They activate NK cells, cause bystander activation of mDC, and interact with T cells to induce tolerance. This ambiguity positions pDC at the center of inflammatory diseases, such as cancer, arthritis, and autoimmune diseases. The ability to generate human mDC ex vivo made it possible to engineer them to suit therapy needs. Unfortunately, a similar, easily accessible system to generate human pDC is not available. We describe a method to generate human pDC equivalents ex vivo, termed mo-pDC from peripheral blood monocytes using Flt3-L. mo-pDC showed a characteristic pDC profile, such as high CD123 and BDCA4, but low CD86 and TLR4 surface expression and a low capacity to induce autologous lymphocyte proliferation and to phagocytose apoptotic debris in comparison with mDC. Interestingly, mo-pDC up-regulated the pDC lineage-determining transcription factor E2-2 as well as expression of BDCA2, which is under the transcriptional control of E2-2 but not its inhibitor ID2, during differentiation. mo-pDC produced high levels of IFN-alpha when pretreated overnight with TNF-alpha. Under hypoxia, E2-2 was down-regulated, and ID2 was induced in mo-pDC, whereas surface expression of MHCI, CD86, and BDCA2 was decreased. Furthermore, mo-pDC produced high levels of inflammatory cytokines when differentiated under hypoxia compared with normoxia. Hence, mo-pDC can be used to study differentiation and functions of human pDC under microenvironmental stimuli.

Dual Tracer PET Imaging with FDG and FLT Differentiates Tuberculous Lymphadenopathy from Metastases in a Case of Carcinoma Cervix

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Joshi, Prathamesh; Lele, Vikram; Aland, Parag; Gemawat, Shilpa [Jaslok Hospital and Research Centre, Woril (India)

2013-09-15

A forty-year-old woman with a known case of carcinoma cervix underwent 18-fluorodeoxyglucose positron emission tomography.computed tomography (18-FDG PET/CT) for evaluation of abdominal lymphadenopathy. Her treatment history included radical hysterectomy and radiotherapy 6 months ago. She complained of weight loss of 7 kg over last 5 months. The maximum intensity projection (MIP) image (Fig. 1a, arrows) revealed multiple areas of intense FDG uptake, which on CT and fused PET/CT images were localized to multiple lymph nodes in bilateral cervical region, right axilla, mediastinum and abdomen. The SUVmax of right axillary lymph nodes (most FDG avid of all lymph node groups) was 15.3. There was no evidence of metabolically active disease or CT demonstrable abnormality in rest of the body. Presence of metabolically active disease in extensive supradiaphramatic lymphadenopathy was unusual for a case of carcinoma cervix. This finding, along with history of significant weight loss and absence of extranodal disease, was suspicious for unrelated pathology like lymphoproliferative disorder or granulomatous disease. Mixed malignant and benign lymphadenopathy was also considered a possibility. To solve the conundrum, 18-fluoro-L-thymidine (FLT) PET/CT was performed on the next day. This scan was performed to assess the proliferation rate in various above-mentioned lymph nodes, and to plan the optimum site of biopsy. The FLT PET scan (Fig. 1b) showed physiological distribution of the tracer in bone marrow, liver, gall bladder and urinary bladder. There was minimal FLT uptake in the enlarged, FDG avid lymph nodes (Fig. 1c and d). SUVmax of FLT uptake in right axillary lymph nodes was 1.4 (SUVmax of FDG uptake = 15.8). The SUVmax of FLT uptake in cervical, mediastinal and abdominal lymph nodes were 1.3, 1.4 and 1.0 respectively. (SUVmax of FDG uptake 12.1, 12.7 and 11.9, respectively). Considering avidity for FDG and non-avidity of proliferation marker tracer (FLT), possibility of

FLT3-ITD and MLL-PTD influence the expression of MDR-1, MRP-1, and BCRP mRNA but not LRP mRNA assessed with RQ-PCR method in adult acute myeloid leukemia.

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Nasilowska-Adamska, Barbara; Solarska, Iwona; Paluszewska, Monika; Malinowska, Iwona; Jedrzejczak, Wieslaw W; Warzocha, Krzysztof

2014-04-01

Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) and mixed-lineage leukemia gene-partial tandem duplication (MLL-PTD) are aberrations associated with leukemia which indicate unsatisfactory prognosis. Downstream regulatory targets of FLT3-ITD and MLL-PTD are not well defined. We have analyzed the expression of MDR-1, multidrug resistant protein-1 (MRP-1), breast cancer resistance protein (BCRP), and lung resistance protein (LRP) messenger RNA (mRNA) in relation to the mutational status of FLT3-ITD and MLL-PTD in 185 acute myeloid leukemia (AML) adult patients. The real-time quantitative polymerase chain reaction method was performed to assess the expression of the MDR-1, MRP-1, BCRP, and LRP mRNA, and the results were presented as coefficients calculated using an intermediate method according to Pfaffl's rule. Significantly higher expressions of MDR-1 mRNA were found in patients who did not harbor FLT3-ITD (0.20 vs. 0.05; p = 0.0001) and MRP-1 mRNA in patients with this mutation (0.96 vs. 0.70; p = 0.002) and of BCRP mRNA in patients with MLL-PTD (0.61 vs. 0.38; p = 0.03). In univariate analysis, the high expression of MDR-1 mRNA (≥0.1317) negatively influenced the outcome of induction therapy (p = 0.05), whereas the high expression of BCRP mRNA (≥1.1487) was associated with a high relapse rate (RR) (p = 0.013). We found that the high expression of MDR-1 (≥0.1317), MRP-1 (≥0.8409), and BCRP mRNA (≥1.1487) significantly influenced disease-free survival (DFS; p = 0.059, 0.032, and 0.009, respectively) and overall survival (0.048, 0.014, and 0.059, respectively). Moreover, a high expression of BCRP mRNA (≥1.1487) proved to be an independent prognostic factor for RR (p = 0.01) and DFS (p = 0.002) in multivariate analysis. The significant correlation between the expression of MDR-1, MRP-1, and BCRP mRNA and FLT3-ITD or MLL-PTD in AML patients requires further investigation.

Placental-Specific sFLT-1 e15a Protein Is Increased in Preeclampsia, Antagonizes Vascular Endothelial Growth Factor Signaling, and Has Antiangiogenic Activity.

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Palmer, Kirsten R; Kaitu'u-Lino, Tu'uhevaha J; Hastie, Roxanne; Hannan, Natalie J; Ye, Louie; Binder, Natalie; Cannon, Ping; Tuohey, Laura; Johns, Terrance G; Shub, Alexis; Tong, Stephen

2015-12-01

In preeclampsia, the antiangiogenic factor soluble fms-like tyrosine kinase-1 (sFLT-1) is released from placenta into the maternal circulation, causing endothelial dysfunction and organ injury. A recently described splice variant, sFLT-1 e15a, is primate specific and the most abundant placentally derived sFLT-1. Therefore, it may be the major sFLT-1 isoform contributing to the pathophysiology of preeclampsia. sFLT-1 e15a protein remains poorly characterized: its bioactivity has not been comprehensively examined, and serum levels in normal and preeclamptic pregnancy have not been reported. We generated and validated an sFLT-1 e15a-specific ELISA to further characterize serum levels during pregnancy, and in the presence of preeclampsia. Furthermore, we performed assays to examine the bioactivity and antiangiogenic properties of sFLT-1 e15a protein. sFLT-1 e15a was expressed in the syncytiotrophoblast, and serum levels rose across pregnancy. Strikingly, serum levels were increased 10-fold in preterm preeclampsia compared with normotensive controls. We confirmed sFLT-1 e15a is bioactive and is able to inhibit vascular endothelial growth factor signaling of vascular endothelial growth factor receptor 2 and block downstream Akt phosphorylation. Furthermore, sFLT-1 e15a has antiangiogenic properties. sFLT-1 e15a decreased endothelial cell migration, invasion, and inhibited endothelial cell tube formation. Administering sFLT-1 e15a blocked vascular endothelial growth factor induced sprouts from mouse aortic rings ex vivo. We have demonstrated that sFLT-1 e15a is increased in preeclampsia, antagonizes vascular endothelial growth factor signaling, and has antiangiogenic activity. Future development of diagnostics and therapeutics for preeclampsia should consider targeting placentally derived sFLT-1 e15a. © 2015 American Heart Association, Inc.

Triamide mercaptide (N/sub 3/S) ligands for Tc-99m as potential Tc-99m renal function agents

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Fritzberg, A.R.; Kasina, S.; Johnson, D.L.; Eshima, D.

1985-01-01

A number of diamide dimercaptide (N/sub 2/S/sub 2/) complexes of Tc-99m have shown potential as renal tubular function radiopharmaceuticals that could replace radioiodinated hippurate (OIH). Evaluation of such ligands suggested that maximum efficiency for tubular secretion and specificity resulted from addition of a carboxylate group. However, such derivatives resulted in chelate ring stereoisomers that were differently transported by the renal tubular system. The problem of stereoisomers was obviated by replacing one sulfur with an effectively planar amido nitrogen. Groups on the nitrogen then result in diastereomers only when an additional asymetric center is present. A series of triamide mercaptide compounds have been synthesized to evaluate this class as ligands for Tc-99m. One of the simplest of the series, mercaptoacetylglycylglycylglycine (MAG/sub 3/), formed a single Tc-99m product in high yield as determined by HPLC. Preliminary results with pmr and ms of the Tc-99 complex indicate a structure consistent with a 1:1 metal to ligand ratio and monooxo technetium group. Biological evaluation of Tc-99m MAG/sub 3/ showed high renal specificity and rate of excretion exceeding OIH in several species including humans. Members of the N/sub 3/S series studied include mercaptoacetylglycylglycyl-amino acids. In some cases with second asymmetric centers, two components were seen on HPLC. In mice several dianionic Tc-99m complexes were excreted faster than OIH, Tc-99m MAG/sub 2/-ala, -asn, and -gln. Trianionic Tc-99m MAG/sub 2/-asp and -glu were excreted more slowly, and Tc-99m MAG/sub 2/-phe showed hepatobiliary excretion. Triamide mercaptides represent a new ligand class for Tc-99m

Preclinical FLT-PET and FDG-PET imaging of tumor response to the multi-targeted Aurora B kinase inhibitor, TAK-901

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Cullinane, Carleen; Waldeck, Kelly L.; Binns, David; Bogatyreva, Ekaterina; Bradley, Daniel P.; Jong, Ron de; McArthur, Grant A.; Hicks, Rodney J.

2014-01-01

Introduction: The Aurora kinases play a key role in mitosis and have recently been identified as attractive targets for therapeutic intervention in cancer. The aim of this study was therefore to investigate the utility of 3′-[ 18 F]fluoro-3′-deoxythymidine (FLT) and 2-deoxy-2-[ 18 F]fluoro-D-glucose (FDG) for assessment of tumor response to the multi-targeted Aurora B kinase inhibitor, TAK-901. Methods: Balb/c nude mice bearing HCT116 colorectal xenografts were treated with up to 30 mg/kg TAK 901 or vehicle intravenously twice daily for two days on a weekly cycle. Tumor growth was monitored by calliper measurements and PET imaging was performed at baseline, day 4, 8, 11 and 15. Tumors were harvested at time points corresponding to days of PET imaging for analysis of ex vivo markers of cell proliferation and metabolism together with markers of Aurora B kinase inhibition including phospho-histone H3 (pHH3) and senescence associated β-galactosidase. Results: Tumor growth was inhibited by 60% on day 12 of 30 mg/kg TAK-901 therapy. FLT uptake was significantly reduced by day 4 of treatment and this corresponded with reduction in bromodeoxyuridine and pHH3 staining by immunohistochemistry. All biomarkers rebounded towards baseline levels by the commencement of the next treatment cycle, consistent with release of Aurora B kinase suppression. TAK-901 therapy had no impact on glucose metabolism as assessed by FDG uptake and GLUT1 staining by immunohistochemistry. Conclusions: FLT-PET, but not FDG-PET, is a robust non-invasive imaging biomarker of early HCT116 tumor response to the on-target effects of the multi-targeted Aurora B kinase inhibitor, TAK-901. Advances in knowledge and implications for patient care: This is the first report to demonstrate the impact of the multi-targeted Aurora B kinase inhibitor, TAK-901 on tumor FLT uptake. The findings provide a strong rationale for the evaluation of FLT-PET as an early biomarker of tumor response in the early phase

Secretion of soluble vascular endothelial growth factor receptor 1 (sVEGFR1/sFlt1 requires Arf1, Arf6, and Rab11 GTPases.

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Jae-Joon Jung

Full Text Available The soluble form of vascular endothelial growth factor receptor 1 (sVEGFR-1/sFlt1 is generated by alternative splicing of the FLT1 gene. Secretion of sFlt1 from endothelial cells plays an important role in blood vessel sprouting and morphogenesis. However, excess sFlt1 secretion is associated with diseases such as preeclampsia and chronic kidney disease. To date, the secretory transport process involved in the secretion of sFlt1 is poorly understood. In the present study, we investigated the itinerary of sFlt1 trafficking along the secretory pathway. To understand the timecourse of sFlt1 secretion, endothelial cells stably expressing sFlt1 were metabolically radiolabeled with [(35S]-methionine and cysteine. Our results indicate that after initial synthesis the levels of secreted [(35S]-sFlt1 in the extracellular medium peaks at 8 hours. Treatment with brefeldin A (BFA, a drug which blocks trafficking between the endoplasmic reticulum (ER and the Golgi complex, inhibited extracellular release of sFlt1 suggesting that ER to Golgi and intra-Golgi trafficking of sFlt1 are essential for its secretion. Furthermore, we show that ectopic expression of dominant-negative mutant forms of Arf1, Arf6, and Rab11 as well as siRNA-mediated knockdown of these GTPases block secretion of sFlt1 during normoxic and hypoxic conditions suggesting role for these small GTPases. This work is the first to report role of regulatory proteins involved in sFlt1 trafficking along the secretory pathway and may provide insights and new molecular targets for the modulation of sFlt-1 release during physiological and pathological conditions.

Intratumoral heterogeneity of 18F-FLT uptake predicts proliferation and survival in patients with newly diagnosed gliomas

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Mitamura, Katsuya; Yamamoto, Yuka; Kudomi, Nobuyuki; Norikane, Takashi; Miyake, Keisuke; Nishiyama, Yoshihiro; Maeda, Yukito

2017-01-01

The nucleoside analog 3'-deoxy-3'- 18 F-fluorothymidine (FLT) has been investigated for evaluating tumor proliferating activity in brain tumors. We evaluated FLT uptake heterogeneity using textural features from the histogram analysis in patients with newly diagnosed gliomas and examined correlation of the results with proliferative activity and patient prognosis, in comparison with the conventional PET parameters. FLT PET was investigated in 37 patients with newly diagnosed gliomas. The conventional parameters [tumor-to-contralateral normal brain tissue (T/N) ratio and metabolic tumor volume (MTV)] and textural parameters (standard deviation, skewness, kurtosis, entropy, and uniformity) were derived from FLT PET images. Linear regression analysis was used to compare PET parameters and the proliferative activity as indicated by the Ki-67 index. The associations between parameters and overall survival (OS) were tested by Cox regression analysis. Median OS was 662 days. For the conventional parameters, linear regression analysis indicated a significant correlation between T/N ratio and Ki-67 index (p = 0.02) and MTV and Ki-67 index (p = 0.02). Among textural parameters, linear regression analysis indicated a significant correlation for kurtosis (p = 0.003), entropy (p < 0.001), and uniformity (p < 0.001) as compared to Ki-67 index, exceeding those of the conventional parameters. The results of univariate analysis suggested that skewness and kurtosis were associated with OS (p = 0.03 and 0.02, respectively). Mean survival for patients with skewness values less than 0.65 was 1462 days, compared with 917 days for those with values greater than 0.65 (p = 0.02). Mean survival for patients with kurtosis values less than 6.16 was 1616 days, compared with 882 days for those with values greater than 6.16 (p = 0.006). Based on the results of this preliminary study in a small patient population, textural features reflecting heterogeneity on FLT PET images seem to be

Early assessment of the efficacy of temozolomide chemotherapy in experimental glioblastoma using [18F]FLT-PET imaging.

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Thomas Viel

Full Text Available UNLABELLED: Addition of temozolomide (TMZ to radiation therapy is the standard treatment for patients with glioblastoma (GBM. However, there is uncertainty regarding the effectiveness of TMZ. Considering the rapid evolution of the disease, methods to assess TMZ efficacy early during treatment would be of great benefit. Our aim was to monitor early effects of TMZ in a mouse model of GBM using positron emission tomography (PET with 3'-deoxy-3'-[(18F]fluorothymidine ([(18F]FLT. METHODS: Human glioma cells sensitive to TMZ (Gli36dEGFR-1 were treated with sub-lethal doses of TMZ to obtain cells with lower sensitivity to TMZ (Gli36dEGFR-2, as measured by growth and clonogenic assays. Gli36dEGFR-1 and Gli36dEGFR-2 cells were subcutaneously (s.c. or intracranially (i.c. xenografted into nude mice. Mice were treated for 7 days with daily injection of 25 or 50 mg/kg TMZ. Treatment efficacy was measured using [(18F]FLT-PET before treatment and after 2 days. Computed Tomography (CT or Magnetic Resonance Imaging (MRI were used to determine tumor volumes before treatment and after 7 days. RESULTS: A significant difference was observed between TMZ and DMSO treated tumors in terms of variations of [(18F]FLT T/B ratio as soon as day 2 in the i.c. as well as in the s.c. mouse model. Variations of [(18F]FLT T/B uptake ratio between days 0 and 2 correlated with variations of tumor size between days 0 and 7 (s.c. model: n(tumor = 17 in n(mice = 11, P<0.01; i.c. model: n(tumor/mice = 9, P<0.01. CONCLUSIONS: Our results indicate that [(18F]FLT-PET may be useful for an early evaluation of the response of GBM to TMZ chemotherapy in patients with glioma.

Comparison of 18F-FET and 18F-FLT small animal PET for the assessment of anti-VEGF treatment response in an orthotopic model of glioblastoma

International Nuclear Information System (INIS)

Nedergaard, Mette Kjoelhede; Michaelsen, Signe Regner; Perryman, Lara; Erler, Janine; Poulsen, Hans Skovgaard; Stockhausen, Marie-Thérése; Lassen, Ulrik; Kjaer, Andreas

2016-01-01

Background: The radiolabeled amino acid O-(2- 18 F-fluoroethyl)-L-tyrosine (FET) and thymidine analogue 3′-deoxy-3′- 18 F-fluorothymidine (FLT) are widely used for positron emission tomography (PET) brain tumor imaging; however, comparative studies are scarce. The aim of this study therefore was to compare FLT and FET PET for the assessment of anti-VEGF response in glioblastoma xenografts. Methods: Xenografts with confirmed intracranial glioblastoma were treated with anti-VEGF therapy (B20-4.1) or saline as control. Weekly bioluminescence imaging (BLI), FLT and FET PET/CT were used to follow treatment response. Tracer uptake of FLT and FET was quantified using maximum standardized uptake (SUV max ) values and tumor-to-background ratios (TBRs). Survival, the Ki67 proliferation index and micro-vessel density (MVD) were evaluated. Results: In contrast to FLT TBRs, FET TBRs were significantly lower as early as one week after treatment initiation in the anti-VEGF group as compared to the control group. Following two weeks of treatment, both FLT and FET TBRs were significantly lower in the anti-VEGF group. In contrast, no significant difference between the treatment groups was detected using BLI. Furthermore, we found a significantly lower MVD in the anti-VEGF group as compared to the control group. However, we found no difference in the Ki67 proliferation index or mean survival time. Conclusion: FET appears to be a more sensitive tracer than FLT to measure early response to anti-VEGF therapy with PET. Advances in knowledge and implications for patient care FET PET appears to be an early predictor of anti-VEGF efficacy. Confirmation of these results in clinical studies is needed.

Prognostic value of 18F-FLT PET in patients with neuroendocrine neoplasms

DEFF Research Database (Denmark)

Johnbeck, Camilla B.; Knigge, Ulrich; Langer, Seppo W.

2016-01-01

Neuroendocrine neoplasms (NENs) constitute a heterogeneous group of tumors arising in various organs and with a large span of aggressiveness and survival rates. The Ki-67 proliferation index is presently used as the key marker of prognosis, and treatment guidelines are largely based on this index...... study was to investigate 18F-FLT PET as a prognostic marker for NENs in comparison with 18F-FDG PET and Ki-67 index. Methods: One hundred patients were PET-scanned with both 18F-FLT and 18F-FDG within the same week, and the prognostic value of a positive scan was examined in terms of progression...... prognostic value in NEN patients but when 18F-FDG PET and Ki-67 index are also available, a multivariate model revealed that 18F-FLT PET only adds information regarding PFS but not OS, whereas 18F-FDG PET remains predictive of both PFS and OS. However, a clinically robust algorithm including 18F...

FDG-PET/CT and FLT-PET/CT for differentiating between lipid-poor benign and malignant adrenal tumours

Energy Technology Data Exchange (ETDEWEB)

Nakajo, Masatoyo; Jinguji, Megumi; Fukukura, Yoshihiko; Nakabeppu, Yoshiaki; Nakamura, Fumihiko; Yoshiura, Takashi [Kagoshima University, Department of Radiology, Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Kajiya, Yoriko; Tani, Atushi; Nakajo, Masayuki [Nanpuh Hospital, Department of Radiology, Kagoshima (Japan); Arimura, Hiroshi; Nishio, Yoshihiko [Kagoshima University, Department of Diabetes and Endocrine Medicine, Graduate School of Medical and Dental Sciences, Kagoshima (Japan)

2015-12-15

To compare F-18-fluorodeoxyglucose (FDG) and F-18-fluorothymidine (FLT) PET/CT examinations for differentiating between benign and malignant adrenal tumours. Thirty lipid-poor benign and 11 malignant tumours of 40 patients were included. FDG- and FLT-based indices including visual score, maximum standardized uptake value (SUVmax) and FDG adrenal lesion/liver SUVmax (A/L SUVmax) or FLT adrenal lesion/back muscle SUVmax (A/B SUVmax) ratio were compared between benign and malignant tumours using the Mann-Whitney's U or Wilcoxon signed-rank test, and their diagnostic performances were evaluated by means of the area under the curve (AUC) values derived from the receiver operating characteristic analysis. All indices were significantly higher in malignant than benign tumours on both images (p < 0.05 each). On FDG-PET/CT, the sensitivity, specificity, and accuracy were 91 %, 63 % and 71 % for visual score, 91 %, 67 % and 73 % for SUVmax, and 100 %, 70 % and 78 % for A/L SUVmax ratio, respectively. On FLT-PET/CT, they were 100 %, 97 % and 98 % for visual score, SUVmax and A/B SUVmax ratio, respectively. All FLT indices were significantly higher than those of FDG in AUC (p < 0.05 each). FLT-PET/CT may be superior to FDG-PET/CT in differentiating lipid-poor benign from malignant adrenal tumours because of higher specificity and accuracy. (orig.)

Detection of TET2, KRAS and CBL variants by Next Generation Sequencing and analysis of their correlation with JAK2 and FLT3 in childhood AML

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Dilara Fatma Akin

2016-04-01

Conclusion: We found novel mutations for TET2, KRAS, and CBL. The detected variants in this article seem to be the first screening results of genes studied by NGS in childhood AML patients. Our results also showed some degree of association between FLT3-ITD and TET2, KRAS, CBL mutations.

Acute WT1-positive promyelocytic leukemia with hypogranular variant morphology, bcr-3 isoform of PML-RARα and Flt3-ITD mutation: a rare case report

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Xi Zhang

Full Text Available ABSTRACT CONTEXT: Acute promyelocytic leukemia (APL accounts for 8% to 10% of cases of acute myeloid leukemia (AML. Remission in cases of high-risk APL is still difficult to achieve, and relapses occur readily. CASE REPORT: Here, we describe a case of APL with high white blood cell counts in blood tests and hypogranular variant morphology in bone marrow, together with fms-like tyrosine kinase-3 with internal tandem duplication mutations (FLT3-ITD, and bcr-3 isoform of PML-RARα. Most importantly, we detected high level of Wilms’ tumor gene (WT1 in marrow blasts, through the reverse transcription polymerase chain reaction (RT-PCR. To date, no clear conclusions about an association between WT1 expression levels and APL have been reached. This patient successively received a combined treatment regimen consisting of hydroxycarbamide, arsenic trioxide and idarubicin plus cytarabine, which ultimately enabled complete remission. Unfortunately, he subsequently died of sudden massive hemoptysis because of pulmonary infection. CONCLUSION: Based on our findings and a review of the literature, abnormal functioning of WT1 may be a high-risk factor in cases of APL. Further studies aimed towards evaluating the impact of WT1 expression on the prognosis for APL patients are of interest.

Gene Duplication of the zebrafish kit ligand and partitioning of melanocyte development functions to kit ligand a.

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Keith A Hultman

2007-01-01

Full Text Available The retention of particular genes after the whole genome duplication in zebrafish has given insights into how genes may evolve through partitioning of ancestral functions. We examine the partitioning of expression patterns and functions of two zebrafish kit ligands, kit ligand a (kitla and kit ligand b (kitlb, and discuss their possible coevolution with the duplicated zebrafish kit receptors (kita and kitb. In situ hybridizations show that kitla mRNA is expressed in the trunk adjacent to the notochord in the middle of each somite during stages of melanocyte migration and later expressed in the skin, when the receptor is required for melanocyte survival. kitla is also expressed in other regions complementary to kita receptor expression, including the pineal gland, tail bud, and ear. In contrast, kitlb mRNA is expressed in brain ventricles, ear, and cardinal vein plexus, in regions generally not complementary to either zebrafish kit receptor ortholog. However, like kitla, kitlb is expressed in the skin during stages consistent with melanocyte survival. Thus, it appears that kita and kitla have maintained congruent expression patterns, while kitb and kitlb have evolved divergent expression patterns. We demonstrate the interaction of kita and kitla by morpholino knockdown analysis. kitla morphants, but not kitlb morphants, phenocopy the null allele of kita, with defects for both melanocyte migration and survival. Furthermore, kitla morpholino, but not kitlb morpholino, interacts genetically with a sensitized allele of kita, confirming that kitla is the functional ligand to kita. Last, we examine kitla overexpression in embryos, which results in hyperpigmentation caused by an increase in the number and size of melanocytes. This hyperpigmentation is dependent on kita function. We conclude that following genome duplication, kita and kitla have maintained their receptor-ligand relationship, coevolved complementary expression patterns, and that

Application of a whole-body pharmacokinetic model for targeted radionuclide therapy to NM404 and FLT

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Grudzinski, Joseph J.; Floberg, John M.; Mudd, Sarah R.; Jeffery, Justin J.; Peterson, Eric T.; Nomura, Alice; Burnette, Ronald R.; Tomé, Wolfgang A.; Weichert, Jamey P.; Jeraj, Robert

2012-03-01

We have previously developed a model that provides relative dosimetry estimates for targeted radionuclide therapy (TRT) agents. The whole-body and tumor pharmacokinetic (PK) parameters of this model can be noninvasively measured with molecular imaging, providing a means of comparing potential TRT agents. Parameter sensitivities and noise will affect the accuracy and precision of the estimated PK values and hence dosimetry estimates. The aim of this work is to apply a PK model for TRT to two agents with different magnitudes of clearance rates, NM404 and FLT, explore parameter sensitivity with respect to time and investigate the effect of noise on parameter precision and accuracy. Twenty-three tumor bearing mice were injected with a ‘slow-clearing’ agent, 124I-NM404 (n = 10), or a ‘fast-clearing’ agent, 18F-FLT (3‧-deoxy-3‧-fluorothymidine) (n = 13) and imaged via micro-PET/CT pseudo-dynamically or dynamically, respectively. Regions of interest were drawn within the heart and tumor to create time-concentration curves for blood pool and tumor. PK analysis was performed to estimate the mean and standard error of the central compartment efflux-to-influx ratio (k12/k21), central elimination rate constant (kel), and tumor influx-to-efflux ratio (k34/k43), as well as the mean and standard deviation of the dosimetry estimates. NM404 and FLT parameter estimation results were used to analyze model accuracy and parameter sensitivity. The accuracy of the experimental sampling schedule was compared to that of an optimal sampling schedule found using Cramer-Rao lower bounds theory. Accuracy was assessed using correlation coefficient, bias and standard error of the estimate normalized to the mean (SEE/mean). The PK parameter estimation of NM404 yielded a central clearance, kel (0.009 ± 0.003 h-1), normal body retention, k12/k21 (0.69 ± 0.16), tumor retention, k34/k43 (1.44 ± 0.46) and predicted dosimetry, Dtumor (3.47 ± 1.24 Gy). The PK parameter estimation of FLT

Evaluation of Docking Target Functions by the Comprehensive Investigation of Protein-Ligand Energy Minima.

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Oferkin, Igor V; Katkova, Ekaterina V; Sulimov, Alexey V; Kutov, Danil C; Sobolev, Sergey I; Voevodin, Vladimir V; Sulimov, Vladimir B

2015-01-01

The adequate choice of the docking target function impacts the accuracy of the ligand positioning as well as the accuracy of the protein-ligand binding energy calculation. To evaluate a docking target function we compared positions of its minima with the experimentally known pose of the ligand in the protein active site. We evaluated five docking target functions based on either the MMFF94 force field or the PM7 quantum-chemical method with or without implicit solvent models: PCM, COSMO, and SGB. Each function was tested on the same set of 16 protein-ligand complexes. For exhaustive low-energy minima search the novel MPI parallelized docking program FLM and large supercomputer resources were used. Protein-ligand binding energies calculated using low-energy minima were compared with experimental values. It was demonstrated that the docking target function on the base of the MMFF94 force field in vacuo can be used for discovery of native or near native ligand positions by finding the low-energy local minima spectrum of the target function. The importance of solute-solvent interaction for the correct ligand positioning is demonstrated. It is shown that docking accuracy can be improved by replacement of the MMFF94 force field by the new semiempirical quantum-chemical PM7 method.

Evaluation of Docking Target Functions by the Comprehensive Investigation of Protein-Ligand Energy Minima

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Igor V. Oferkin

2015-01-01

Full Text Available The adequate choice of the docking target function impacts the accuracy of the ligand positioning as well as the accuracy of the protein-ligand binding energy calculation. To evaluate a docking target function we compared positions of its minima with the experimentally known pose of the ligand in the protein active site. We evaluated five docking target functions based on either the MMFF94 force field or the PM7 quantum-chemical method with or without implicit solvent models: PCM, COSMO, and SGB. Each function was tested on the same set of 16 protein-ligand complexes. For exhaustive low-energy minima search the novel MPI parallelized docking program FLM and large supercomputer resources were used. Protein-ligand binding energies calculated using low-energy minima were compared with experimental values. It was demonstrated that the docking target function on the base of the MMFF94 force field in vacuo can be used for discovery of native or near native ligand positions by finding the low-energy local minima spectrum of the target function. The importance of solute-solvent interaction for the correct ligand positioning is demonstrated. It is shown that docking accuracy can be improved by replacement of the MMFF94 force field by the new semiempirical quantum-chemical PM7 method.

Forging the Basis for Developing Protein-Ligand Interaction Scoring Functions.

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Liu, Zhihai; Su, Minyi; Han, Li; Liu, Jie; Yang, Qifan; Li, Yan; Wang, Renxiao

2017-02-21

In structure-based drug design, scoring functions are widely used for fast evaluation of protein-ligand interactions. They are often applied in combination with molecular docking and de novo design methods. Since the early 1990s, a whole spectrum of protein-ligand interaction scoring functions have been developed. Regardless of their technical difference, scoring functions all need data sets combining protein-ligand complex structures and binding affinity data for parametrization and validation. However, data sets of this kind used to be rather limited in terms of size and quality. On the other hand, standard metrics for evaluating scoring function used to be ambiguous. Scoring functions are often tested in molecular docking or even virtual screening trials, which do not directly reflect the genuine quality of scoring functions. Collectively, these underlying obstacles have impeded the invention of more advanced scoring functions. In this Account, we describe our long-lasting efforts to overcome these obstacles, which involve two related projects. On the first project, we have created the PDBbind database. It is the first database that systematically annotates the protein-ligand complexes in the Protein Data Bank (PDB) with experimental binding data. This database has been updated annually since its first public release in 2004. The latest release (version 2016) provides binding data for 16 179 biomolecular complexes in PDB. Data sets provided by PDBbind have been applied to many computational and statistical studies on protein-ligand interaction and various subjects. In particular, it has become a major data resource for scoring function development. On the second project, we have established the Comparative Assessment of Scoring Functions (CASF) benchmark for scoring function evaluation. Our key idea is to decouple the "scoring" process from the "sampling" process, so scoring functions can be tested in a relatively pure context to reflect their quality. In our

18F-FDG and 18F-FLT-PET imaging for monitoring everolimus effect on tumor-growth in neuroendocrine tumors: studies in human tumor xenografts in mice.

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Camilla Bardram Johnbeck

Full Text Available The mTOR inhibitor everolimus has shown promising results in some but not all neuroendocrine tumors. Therefore, early assessment of treatment response would be beneficial. In this study, we investigated the in vivo and in vitro treatment effect of everolimus in neuroendocrine tumors and evaluated the performance of 18F-FDG and the proliferation tracer 18F-FLT for treatment response assessment by PET imaging.The effect of everolimus on the human carcinoid cell line H727 was examined in vitro with the MTT assay and in vivo on H727 xenograft tumors. The mice were scanned at baseline with 18F-FDG or 18F-FLT and then treated with either placebo or everolimus (5 mg/kg daily for 10 days. PET/CT scans were repeated at day 1,3 and 10.Everolimus showed significant inhibition of H727 cell proliferation in vitro at concentrations above 1 nM. In vivo tumor volumes measured relative to baseline were significantly lower in the everolimus group compared to the control group at day 3 (126±6% vs. 152±6%; p = 0.016, day 7 (164±7% vs. 226±13%; p<0.001 and at day 10 (194±10% vs. 281±18%; p<0.001. Uptake of 18F-FDG and 18F-FLT showed little differences between control and treatment groups, but individual mean uptake of 18F-FDG at day 3 correlated with tumor growth day 10 (r2 = 0.45; P = 0.034, 18F-FLT mean uptake at day 1 correlated with tumor growth day 7 (r2 = 0.63; P = 0.019 and at day 3 18F-FLT correlated with tumor growth day 7 (r2 = 0.87; P<0.001 and day 10 (r2 = 0.58; P = 0.027.Everolimus was effective in vitro and in vivo in human xenografts lung carcinoid NETs and especially early 18F-FLT uptake predicted subsequent tumor growth. We suggest that 18F-FLT PET can be used for tailoring therapy for neuroendocrine tumor patients through early identification of responders and non-responders.

Ligand-Promoted C(sp(3) )-H Olefination en Route to Multi-functionalized Pyrazoles.

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Yang, Weibo; Ye, Shengqing; Schmidt, Yvonne; Stamos, Dean; Yu, Jin-Quan

2016-05-17

A Pd-catalyzed/N-heterocycle-directed C(sp(3) )-H olefination has been developed. The monoprotected amino acid ligand (MPAA) is found to significantly promote Pd-catalyzed C(sp(3) )-H olefination for the first time. Cu(OAc)2 instead of Ag(+) salts are used as the terminal oxidant. This reaction provides a useful method for the synthesis of alkylated pyrazoles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure-Guided Screening for Functionally Selective D2 Dopamine Receptor Ligands from a Virtual Chemical Library.

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Männel, Barbara; Jaiteh, Mariama; Zeifman, Alexey; Randakova, Alena; Möller, Dorothee; Hübner, Harald; Gmeiner, Peter; Carlsson, Jens

2017-10-20

Functionally selective ligands stabilize conformations of G protein-coupled receptors (GPCRs) that induce a preference for signaling via a subset of the intracellular pathways activated by the endogenous agonists. The possibility to fine-tune the functional activity of a receptor provides opportunities to develop drugs that selectively signal via pathways associated with a therapeutic effect and avoid those causing side effects. Animal studies have indicated that ligands displaying functional selectivity at the D 2 dopamine receptor (D 2 R) could be safer and more efficacious drugs against neuropsychiatric diseases. In this work, computational design of functionally selective D 2 R ligands was explored using structure-based virtual screening. Molecular docking of known functionally selective ligands to a D 2 R homology model indicated that such compounds were anchored by interactions with the orthosteric site and extended into a common secondary pocket. A tailored virtual library with close to 13 000 compounds bearing 2,3-dichlorophenylpiperazine, a privileged orthosteric scaffold, connected to diverse chemical moieties via a linker was docked to the D 2 R model. Eighteen top-ranked compounds that occupied both the orthosteric and allosteric site were synthesized, leading to the discovery of 16 partial agonists. A majority of the ligands had comparable maximum effects in the G protein and β-arrestin recruitment assays, but a subset displayed preference for a single pathway. In particular, compound 4 stimulated β-arrestin recruitment (EC 50 = 320 nM, E max = 16%) but had no detectable G protein signaling. The use of structure-based screening and virtual libraries to discover GPCR ligands with tailored functional properties will be discussed.

Different response patterns of several ligands at the sphingosine-1-phosphate receptor subtype 3 (S1P(3))

NARCIS (Netherlands)

Jongsma, M.; van Unen, J.; van Loenen, P. B.; Michel, M. C.; Peters, S. L. M.; Alewijnse, A. E.

2009-01-01

Recently, some ligands targeting the sphingosine-1-phosphate receptor subtype 3 (S1P(3)) have become available. The characterization of these compounds was mainly based on one functional read-out system, although S1P(3) receptors are known to activate different signal transduction pathways.

SU-E-J-250: A Methodology for Active Bone Marrow Protection for Cervical Cancer Intensity-Modulated Radiotherapy Using 18F-FLT PET/CT Image

International Nuclear Information System (INIS)

Ma, C; Yin, Y

2014-01-01

Purpose: The purpose of this study was to compare a radiation therapy treatment planning that would spare active bone marrow and whole pelvic bone marrow using 18F FLT PET/CT image. Methods: We have developed an IMRT planning methodology to incorporate functional PET imaging using 18F FLT/CT scans. Plans were generated for two cervical cancer patients, where pelvicactive bone marrow region was incorporated as avoidance regions based on the range: SUV>2., another region was whole pelvic bone marrow. Dose objectives were set to reduce the volume of active bone marrow and whole bone marraw. The volumes of received 10 (V10) and 20 (V20) Gy for active bone marrow were evaluated. Results: Active bone marrow regions identified by 18F FLT with an SUV>2 represented an average of 48.0% of the total osseous pelvis for the two cases studied. Improved dose volume histograms for identified bone marrow SUV volumes and decreases in V10(average 18%), and V20(average 14%) were achieved without clinically significant changes to PTV or OAR doses. Conclusion: Incorporation of 18F FLT/CT PET in IMRT planning provides a methodology to reduce radiation dose to active bone marrow without compromising PTV or OAR dose objectives in cervical cancer

TU-F-12A-02: Quantitative Characterization of Normal Bone Marrow Proliferative Activity with FLT PET/CT

Energy Technology Data Exchange (ETDEWEB)

Weisse, N; Jeraj, R [Department of Medical Physics, University of Wisconsin, Madison, WI (United States)

2014-06-15

Purpose: [F-18]FLT PET is a tool for assessing health of bone marrow by evaluating its proliferative activity. This study establishes a baseline quantitative characterization of healthy marrow proliferation to aid in diagnosis of hematological disease. Methods: 31 patients (20 male, 11 female, 41–76 years) being treated for solid cancers with no history of hematological disease, osseous metastatic disease, or radiation therapy received pre-treatment FLT PET/CT scans. Total bone marrow was isolated from whole body FLT PET images by manually removing organs and applying a standardize uptake value (SUV) threshold of 1.0. Because adult marrow is concentrated in the axial skeleton, quantitative total bone marrow analysis (QTBMA) was used to isolate marrow in the lumbar spine, thoracic spine, sacrum, and pelvis for analysis. SUV_mean, SUV_max, and SUV_CV were used to quantify bone marrow proliferation. Correlations were explored between SUV and patient characteristics including age, weight, height, and BMI using the Spearman coefficient (ρ). Results: The population-averaged whole-skeleton SUV_mean, SUV_max, and SUV_CV were 3.0±0.6, 18.4±5.7, and 0.6±0.1, respectively. Uptake values in the axial skeleton were similar to the whole-skeleton demonstrated by SUV_mean in the thoracic spine (3.6±0.6), lumbar spine (3.3±0.5), sacrum (3.0±0.6), and pelvis regions (2.8±0.5). Whole-skeleton SUV_max correlated with patient weight (ρ=0.47, p<0.01) and BMI (ρ=0.60, p<0.01), suggesting marrow activity is related to the body's burden. SUV measures in the thoracic spine, lumbar spine, sacrum, and pelvis were negatively correlated with age (ρ:−0.41 to −0.46, p≤0.02). These negative correlations reflect the fact that active marrow in the adult skeleton is localized in the axial skeleton and decreases with age. Conclusions: Normal bone marrow characterizations were determined using FLT

Allogeneic stem cell transplantation benefits for patients ≥ 60 years with acute myeloid leukemia and FLT3 internal tandem duplication: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

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Poiré, Xavier; Labopin, Myriam; Polge, Emmanuelle; Passweg, Jakob; Craddock, Charles; Blaise, Didier; Cornelissen, Jan J; Volin, Liisa; Russell, Nigel H; Socié, Gérard; Michallet, Mauricette; Fegueux, Nathalie; Chevallier, Patrice; Brecht, Arne; Hunault-Berger, Mathilde; Mohty, Mohamad; Esteve, Jordi; Nagler, Arnon

2018-02-01

Intermediate-risk cytogenetic acute myeloid leukemia with an internal tandem duplication of FLT3 ( FLT3 -ITD) is associated with a high risk of relapse, and is now a standard indication for allogeneic stem cell transplantation. Nevertheless, most studies supporting this strategy have been performed in young patients. To address the benefit of allogeneic transplantation in the elderly, we made a selection from the European Society for Blood and Marrow Transplantation registry of de novo intermediate-risk cytogenetic acute myeloid leukemia harboring FLT3 -ITD in patients aged 60 or over and transplanted from a related or unrelated donor between January 2000 and December 2015. Two hundred and ninety-one patients were identified. Most patients received a reduced-intensity conditioning (82%), while donors consisted of an unrelated donor in 161 (55%) patients. Two hundred and twelve patients received their transplantation in first remission, 37 in second remission and 42 in a more advanced stage of the disease. The 2-year leukemia-free survival rate was 56% in patients in first remission, 22% in those in second remission and 10% in patients with active disease, respectively ( P <0.005). Non-relapse mortality for the entire cohort was 20%. In multivariate analysis, disease status at transplantation was the most powerful predictor of worse leukemia-free survival, graft- versus -host disease and relapse-free survival, and overall survival. In this elderly population, age was not associated with outcome. Based on the current results, allogeneic transplantation translates into a favorable outcome in fit patients ≥ 60 with FLT3 -ITD acute myeloid leukemia in first remission, similarly to current treatment recommendations for younger patients. Copyright© 2018 Ferrata Storti Foundation.

Glucocorticoid-induced TNF receptor family related protein ligand [GITR-L] is requisite for optimal functioning of regulatory CD4+ T cells.

Directory of Open Access Journals (Sweden)

Gongxian eLiao

2014-02-01

Full Text Available Glucocorticoid-Induced Tumor necrosis factor Receptor family-related protein (GITR, TNFRSF18, CD357 is constitutively expressed on regulatory T cells (Tregs and is inducible on effector T cells (Teffs. In this report, we examine the role of GITR-Ligand (GITR-L, which is expressed by antigen presenting cells, on the development and expansion of Tregs. We found that GITR-L is dispensable for the development of naturally occurring FoxP3+ Treg cells in the thymus. However, the expansion of Treg in GITR-L-/- mice is impaired after injection of the dendritic cells (DCs inducing factor Flt3 ligand. Furthermore, DCs from the liver of GITR-L-/- mice were less efficient in inducing proliferation of antigen-specific Treg cells in vitro than the same cells from WT littermates. Upon gene transfer of ovalbumin into hepatocytes of GITR-L-/- FoxP3(GFP reporter mice using adeno-associated virus (AAV8-OVA the number of antigen-specific Treg in liver and spleen is reduced. The reduced number of Tregs resulted in an increase in the number of ovalbumin specific CD8+ T effector cells. This is highly significant because proliferation of antigen specific CD8+ cells itself is dependent on the presence of GITR-L, as shown by in vitro experiments and by adoptive transfers into GITR-L-/-Rag-/- and Rag-/- mice that had received AAV8-OVA. Surprisingly, administering αCD3 significantly reduced the numbers of FoxP3+ Treg cells in the liver and spleen of GITR-L-/- but not WT mice. Because soluble Fc-GITR-L partially rescues αCD3 induced in vitro depletion of the CD103+ subset of FoxP3+CD4+ Treg cells, we conclude that expression of GITR-L by antigen presenting cells is requisite for optimal Treg-mediated regulation of immune responses including those in response during gene transfer.

Uteroplacental arterio-venous difference in soluble VEGFR-1 (sFlt-1), but not in soluble endoglin concentrations in preeclampsia.

Science.gov (United States)

Paasche Roland, M C; Lorentzen, B; Godang, K; Henriksen, T

2012-03-01

The aim was to determine plasma levels of sFlt-1 and sEng on the arterial and venous side of the uteroplacental circulation in preeclamptic patients and healthy controls. Preeclamptic patients had higher arterial concentrations than controls of sFlt-1 (17,450 vs. 5055 pg/ml, p = 0.003) and sEng (68.7 vs. 28.7 ng/ml, p = 0.003). In the preclampsia group sFlt-1 was higher in the uterine vein than in the radial artery (22,450 vs. 17,450 pg/ml, p = 0.005). We found no gradient for sEng. Our results support the hypothesis that excess sFlt-1 at least partly originates in placenta, while excess sEng appears to have a different origin. Copyright © 2012 Elsevier Ltd. All rights reserved.

Solid phase extraction of Am (III) by resins impregnated with multiply diglycolamide-functionalized ligands

International Nuclear Information System (INIS)

Gujar, R.B.; Ansari, S.A.; Mohapatra, P.K.; Verboom, W.

2016-01-01

Solvent extraction studies with multiply diglycolamide-functionalized extractants such as tripodal diglycolamide (T-DGA) or diglycolamide-functionalized calix(4)arene (C4DGA) ligands have shown excellent results as compared to those of normal DGA ligands such as TODGA. A very high selectivity for Am(III) has been reported with these ligands with respect to U(VI) and Pu(IV). High selectivities and large extraction efficiencies of these ligands towards trivalent f elements were ascribed to a co-operative complexation mechanism. Furthermore, the extraction efficiency of these ligands increased several folds in ionic liquid medium as compared to paraffinic solvents. It was of interest, therefore, to prepare extraction chromatographic resins by impregnation of solvent systems containing these ligands in an ionic liquid. In the present work, solid phase extraction studies were carried out using these two multiply diglycolamide-functionalized extractants, viz. T-DGA (resin I) and C4DGA (resin-II) containing the ionic liquid C 4 mim. NTf 2 impregnated on Chromosorb-W

Studies on ligand exchange reaction of functionalized mercaptothiadiazole compounds onto citrate capped gold nanoparticles

International Nuclear Information System (INIS)

Kalimuthu, Palraj; John, S. Abraham

2010-01-01

Mercaptothiadiazole ligands functionalized with thiol (2,5-dimercapto-1,3,4-thiadiazole (DMT)) and methyl (5-methyl-2-mercapto-1,3,4-thiadiazole (MMT)) groups capped onto citrate capped gold nanoparticles (C-AuNPs) by ligand exchange reaction was investigated by UV-vis spectroscopy, FT-IR spectroscopy and transmission electron microscopy (TEM) techniques. The surface plasmon resonance band at 522 nm for C-AuNPs was shifted to 530 nm after capping with DMT whereas an additional band was observed at 630 nm due to aggregation in addition to a shift in the band at 522 nm after capping of MMT onto C-AuNPs. Thus, capping of DMT onto C-AuNPs leads to the formation of stable AuNPs while capping of MMT leads to the formation of unstable AuNPs. FT-IR studies show that the citrate ions were completely replaced by both DMT and MMT ligands from the AuNPs. TEM images indicate that the size and shape of the AuNPs remain same after capping of these ligands.

Synthesis, density functional theory calculations and luminescence of lanthanide complexes with 2,6-bis[(3-methoxybenzylidene)hydrazinocarbonyl] pyridine Schiff base ligand.

Science.gov (United States)

Taha, Ziyad A; Ababneh, Taher S; Hijazi, Ahmed K; Abu-Salem, Qutaiba; Ajlouni, Abdulaziz M; Ebwany, Shroq

2018-02-01

A pyridine-diacylhydrazone Schiff base ligand, L = 2,6-bis[(3-methoxy benzylidene)hydrazinocarbonyl]pyridine was prepared and characterized by single crystal X-ray diffraction. Lanthanide complexes, Ln-L, {[LnL(NO 3 ) 2 ]NO 3 .xH 2 O (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Er)} were prepared and characterized by elemental analysis, molar conductance, thermal analysis (TGA/DTGA), mass spectrometry (MS), Fourier transform infra-red (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. Ln-L complexes are isostructural with four binding sites provided by two nitro groups along with four coordination sites for L. Density functional theory (DFT) calculations on L and its cationic [LnL(NO 3 ) 2 ] + complexes were carried out at the B3LYP/6-31G(d) level of theory. The FT-IR vibrational wavenumbers were computed and compared with the experimentally values. The luminescence investigations of L and Ln-L indicated that Tb-L and Eu-L complexes showed the characteristic luminescence of Tb(III) and Eu(III) ions. Ln-L complexes show higher antioxidant activity than the parent L ligand. Copyright © 2017 John Wiley & Sons, Ltd.

Destabilization of strigolactone receptor DWARF14 by binding of ligand and E3-ligase signaling effector DWARF3

Science.gov (United States)

Zhao, Li-Hua; Zhou, X Edward; Yi, Wei; Wu, Zhongshan; Liu, Yue; Kang, Yanyong; Hou, Li; de Waal, Parker W; Li, Suling; Jiang, Yi; Scaffidi, Adrian; Flematti, Gavin R; Smith, Steven M; Lam, Vinh Q; Griffin, Patrick R; Wang, Yonghong; Li, Jiayang; Melcher, Karsten; Xu, H Eric

2015-01-01

Strigolactones (SLs) are endogenous hormones and exuded signaling molecules in plant responses to low levels of mineral nutrients. Key mediators of the SL signaling pathway in rice include the α/β-fold hydrolase DWARF 14 (D14) and the F-box component DWARF 3 (D3) of the ubiquitin ligase SCFD3 that mediate ligand-dependent degradation of downstream signaling repressors. One perplexing feature is that D14 not only functions as the SL receptor but is also an active enzyme that slowly hydrolyzes diverse natural and synthetic SLs including GR24, preventing the crystallization of a binary complex of D14 with an intact SL as well as the ternary D14/SL/D3 complex. Here we overcome these barriers to derive a structural model of D14 bound to intact GR24 and identify the interface that is required for GR24-mediated D14-D3 interaction. The mode of GR24-mediated signaling, including ligand recognition, hydrolysis by D14, and ligand-mediated D14-D3 interaction, is conserved in structurally diverse SLs. More importantly, D14 is destabilized upon the binding of ligands and D3, thus revealing an unusual mechanism of SL recognition and signaling, in which the hormone, the receptor, and the downstream effectors are systematically destabilized during the signal transduction process. PMID:26470846

Ligand-Enabled γ-C(sp(3))-H Olefination of Amines: En Route to Pyrrolidines.

Science.gov (United States)

Jiang, Heng; He, Jian; Liu, Tao; Yu, Jin-Quan

2016-02-17

Pd(II)-catalyzed olefination of γ-C(sp(3))-H bonds of triflyl (Tf) and 4-nitrobenzenesulfonyl (Ns) protected amines is achieved. Subsequent aza-Wacker oxidative cyclization or conjugate addition of the olefinated intermediates provides a variety of C-2 alkylated pyrrolidines. Three pyridine- and quinoline-based ligands are developed to match different classes of amine substrates, demonstrating a rare example of ligand-enabled C(sp(3))-H olefination reactions. The use of Ns protecting group to direct C(sp(3))-H activation of alkyl amines is also a significant step toward practical C-H functionalizations of alkyl amines.

Impact of VEGF and VEGF receptor 1 (FLT1) expression on the prognosis of stage III esophageal cancer patients after radiochemotherapy

Energy Technology Data Exchange (ETDEWEB)

Rades, D. [Dept. of Radiation Oncology, Univ. Medical Center Hamburg-Eppendorf (Germany); Dept. of Radiation Oncology, Univ. Hospital Schleswig-Holstein, Luebeck (Germany); Golke, H. [Dept. of Radiation Oncology, Univ. Medical Center Hamburg-Eppendorf (Germany); Inst. of Pathology, Univ. Medical Center Hamburg-Eppendorf (Germany); Schild, S.E. [Dept. of Radiation Oncology, Mayo Clinic, Scottsdale, AZ (United States); Kilic, E. [Inst. of Pathology, Univ. Medical Center Hamburg-Eppendorf (Germany); Inst. of Pathology, Univ. Hospital Basel-Stadt (Switzerland)

2008-08-15

Background and purpose: high expression of vascular endothelial growth factor (VEGF) is negatively associated with clinical outcome. The prognostic value of VEGF receptor 1 (FLT1) is unclear. This retrospective study investigated the impact of tumor expression of VEGF and FLT1 on outcome in 68 stage III esophageal cancer patients. Material and methods: the impact of tumor VEGF and FLT expression (< 10% vs. > 10%) and five additional potential prognostic factors on overall survival (OS) and locoregional control (LC) was retrospectively evaluated. These factors included T-stage (T3 vs. T4), N-stage (NO vs. N1), treatment (radiochemotherapy plus resection vs. radiochemotherapy alone), erythropoietin (ERYPO {sup registered} 10000, Janssen-Cilag, Neuss, Germany) administration during radiotherapy, and majority of hemoglobin levels during radiotherapy (< 12 vs. {>=} 12 g/dl). Subgroup analyses were performed for patients receiving resection (R0 vs. R1/2 resection). The factors found to be significant on univariate analyses (Kaplan-Meier method, log-rank test) were included in multivariate analyses performed with the Cox proportional hazard model. Results: on univariate analysis, improved OS was associated with T3 stage (p = 0.011), surgery (p = 0.019), and hemoglobin {>=} 12 g/dl (p < 0.001). Improved LC was associated with T3 stage (p = 0.025), hemoglobin {>=} 12 g/dl (p < 0.001), and VEGF negativity (p = 0.045). On multivariate analyses, only hemoglobin maintained significance. In patients having surgery, R0 resection was significantly better than R1/2 resection for OS (p < 0.001) and LC (p < 0.001). Conclusion: preradiotherapy tumor VEGF expression appears negatively correlated with outcomes, whereas FLT1 expression appears to have no significant impact on OS and LC. (orig.)

Impact of VEGF and VEGF receptor 1 (FLT1) expression on the prognosis of stage III esophageal cancer patients after radiochemotherapy

International Nuclear Information System (INIS)

Rades, D.; Golke, H.; Schild, S.E.; Kilic, E.

2008-01-01

Background and purpose: high expression of vascular endothelial growth factor (VEGF) is negatively associated with clinical outcome. The prognostic value of VEGF receptor 1 (FLT1) is unclear. This retrospective study investigated the impact of tumor expression of VEGF and FLT1 on outcome in 68 stage III esophageal cancer patients. Material and methods: the impact of tumor VEGF and FLT expression ( 10%) and five additional potential prognostic factors on overall survival (OS) and locoregional control (LC) was retrospectively evaluated. These factors included T-stage (T3 vs. T4), N-stage (NO vs. N1), treatment (radiochemotherapy plus resection vs. radiochemotherapy alone), erythropoietin (ERYPO registered 10000, Janssen-Cilag, Neuss, Germany) administration during radiotherapy, and majority of hemoglobin levels during radiotherapy (< 12 vs. ≥ 12 g/dl). Subgroup analyses were performed for patients receiving resection (R0 vs. R1/2 resection). The factors found to be significant on univariate analyses (Kaplan-Meier method, log-rank test) were included in multivariate analyses performed with the Cox proportional hazard model. Results: on univariate analysis, improved OS was associated with T3 stage (p = 0.011), surgery (p = 0.019), and hemoglobin ≥ 12 g/dl (p < 0.001). Improved LC was associated with T3 stage (p = 0.025), hemoglobin ≥ 12 g/dl (p < 0.001), and VEGF negativity (p = 0.045). On multivariate analyses, only hemoglobin maintained significance. In patients having surgery, R0 resection was significantly better than R1/2 resection for OS (p < 0.001) and LC (p < 0.001). Conclusion: preradiotherapy tumor VEGF expression appears negatively correlated with outcomes, whereas FLT1 expression appears to have no significant impact on OS and LC. (orig.)

Synthesis and luminescence of Eu3+ and Tb3+ complexes with novel calix[4]arene ligands carrying 2,2'-bipyridine subunits

International Nuclear Information System (INIS)

Sabbatini, N.; Guardigli, M.; Manet, I.; Ungaro, R.; Casnati, A.; Fischer, C.; Ziessel, R.; Ulrich, G.

1995-01-01

Eu 3+ and Tb 3+ complexes with novel branched calix[4]arene ligands incorporating 2,2' -bipyridine subunits functionalized in the 6- or 5,5'-positions have been synthesized and their photophysical properties investigated. High luminescence intensity was obtained for the Eu 3+ complex of the calix[4]arene ligand carrying four 5,5' -substituted- 2,2' -bipyridines, which has high molar extinction coefficients (ε max 39 600 M -1 cm -1 ) and a high luminescence quantum yield (15%). (authors). 12 refs., 2 figs., 1 tab

MAML2 rearrangement in primary pulmonary mucoepidermoid carcinoma and the correlation with FLT1 expression.

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Fen Zhu

Full Text Available INTRODUCTION: Primary pulmonary mucoepidermoid carcinoma (PMEC is an uncommon neoplasm with remarkable resemblance to mucoepidermoid carcinoma of the salivary glands. The latter has been shown to harbor t(11,19 resulting in MECT1-MAML2 fusion, which may be of diagnostic and prognostic values. However, the importance of such feature in PMEC has not been well studied. METHODS: We detected MAML2 rearrangement using fluorescence in situ hybridization (FISH in tissue samples from 42 cases of PMEC and 40 of adenosquamous carcinoma (ASC, and the expression of potential downstream targets of MECT1-MAML2, including HES1, FLT1 and NR4A2 with immunohistochemistry (IHC. The findings were then examined regarding the clinicopathological parameters and patient outcomes. RESULTS: FISH analysis revealed MAML2 rearrangement in 50% of the PMEC cases, and such property was prominent in considerable younger patients (33 versus 60 years; p = 0.001 and restricted to cases of low and intermediate grades. IHC analysis showed that FLT1 and HES1 were expressed at lower level in MAML2 rearranged group than MAML2 non-rearranged group (p<0.001 and p = 0.023, respectively. Survival analysis showed significant correlation between MAML2 rearrangement and overall survival (p = 0.023 or disease-free survival (p = 0.027 as well as correlation between FLT1 and overall survival (p = 0.009. CONCLUSIONS: MAML2 rearrangement appears frequent in PMEC and specific with this tumor. Both the presence of MAML2 rearrangement and absence of FLT1 tend to confer a favorable clinical outcome. These findings suggest that molecular detection of MAML2 rearrangement combined with FLT1 may be of important clinical value for PMEC.

GalaxyDock BP2 score: a hybrid scoring function for accurate protein-ligand docking

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Baek, Minkyung; Shin, Woong-Hee; Chung, Hwan Won; Seok, Chaok

2017-07-01

Protein-ligand docking is a useful tool for providing atomic-level understanding of protein functions in nature and design principles for artificial ligands or proteins with desired properties. The ability to identify the true binding pose of a ligand to a target protein among numerous possible candidate poses is an essential requirement for successful protein-ligand docking. Many previously developed docking scoring functions were trained to reproduce experimental binding affinities and were also used for scoring binding poses. However, in this study, we developed a new docking scoring function, called GalaxyDock BP2 Score, by directly training the scoring power of binding poses. This function is a hybrid of physics-based, empirical, and knowledge-based score terms that are balanced to strengthen the advantages of each component. The performance of the new scoring function exhibits significant improvement over existing scoring functions in decoy pose discrimination tests. In addition, when the score is used with the GalaxyDock2 protein-ligand docking program, it outperformed other state-of-the-art docking programs in docking tests on the Astex diverse set, the Cross2009 benchmark set, and the Astex non-native set. GalaxyDock BP2 Score and GalaxyDock2 with this score are freely available at http://galaxy.seoklab.org/softwares/galaxydock.html.

Extraction complexes of Pu(IV) with carbamoylmethylphosphine oxide ligands. A relativistic density functional study

International Nuclear Information System (INIS)

Wang, Cong-Zhi; Lan, Jian-Hui; Feng, Yi-Xiao; Zhao, Yu-Liang; Chai, Zhi-Fang; Shi, Wei-Qun; Wei, Yue-Zhou

2014-01-01

The extraction complexes of Pu(IV) with n-octyl(phenyl)-N,N-diisobutyl-methylcarbamoyl phosphine oxide (CMPO) and diphenyl-N,N-diisobutyl carbamoyl phosphine oxide (Ph 2 CMPO) have been studied by using density functional theory (DFT) combined with relativistic small-core pseudopotentials. For most complexes, the CMPO and Ph 2 CMPO molecules are coordinated as bidentate chelating ligands through the carbonyl oxygen and phosphoric oxygen atoms. The metal-ligand bonding is mainly ionic for all of these complexes. The neutral PuL(NO 3 ) 4 and PuL 2 (NO 3 ) 4 complexes are predicted to be the most thermodynamically stable molecules according to the metal-ligand complexation reactions. In addition, hydration energies may also play a significant role in the extractability of CMPO and Ph 2 CMPO for the plutonium cations. In most cases, the complexes with CMPO possess qualitatively similar geometries and electron structures to those with Ph 2 CMPO, and they also have comparable metal-ligand binding energies. Thus, replacement of alkyl groups by phenyl groups at the phosphorus atom of CMPO seems to have no obvious influence on the extraction of Pu(IV). (orig.)

Acetylation of pregnane X receptor protein determines selective function independent of ligand activation

International Nuclear Information System (INIS)

Biswas, Arunima; Pasquel, Danielle; Tyagi, Rakesh Kumar; Mani, Sridhar

2011-01-01

Research highlights: → Pregnane X receptor (PXR), a major regulatory protein, is modified by acetylation. → PXR undergoes dynamic deacetylation upon ligand-mediated activation. → SIRT1 partially mediates PXR deacetylation. → PXR deacetylation per se induces lipogenesis mimicking ligand-mediated activation. -- Abstract: Pregnane X receptor (PXR), like other members of its class of nuclear receptors, undergoes post-translational modification [PTM] (e.g., phosphorylation). However, it is unknown if acetylation (a major and common form of protein PTM) is observed on PXR and, if it is, whether it is of functional consequence. PXR has recently emerged as an important regulatory protein with multiple ligand-dependent functions. In the present work we show that PXR is indeed acetylated in vivo. SIRT1 (Sirtuin 1), a NAD-dependent class III histone deacetylase and a member of the sirtuin family of proteins, partially mediates deacetylation of PXR. Most importantly, the acetylation status of PXR regulates its selective function independent of ligand activation.

Anti-angiogenesis therapy based on the bone marrow-derived stromal cells genetically engineered to express sFlt-1 in mouse tumor model

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Chen X-C

2008-10-01

Full Text Available Abstract Background Bone marrow-derived stromal cells (BMSCs are important for development, tissue cell replenishment, and wound healing in physiological and pathological conditions. BMSCs were found to preferably reach sites undergoing the process of cell proliferation, such as wound and tumor, suggesting that BMSCs may be used as a vehicle for gene therapy of tumor. Methods Mouse BMSCs were loaded with recombinant adenoviruses which express soluble Vascular Endothelial Growth Factor Receptor-1 (sFlt-1. The anti-angiogenesis of sFlt-1 in BMSCs was determined using endothelial cells proliferation inhibition assay and alginate encapsulation assay. The anti-tumor effects of BMSCs expressing sFlt-1 through tail-vein infusion were evaluated in two mouse tumor metastases models. Results BMSCs genetically modified with Adv-GFP-sFlt-1 could effectively express and secret sFlt-1. BMSCs loaded with sFlt-1 gene could preferentially home to tumor loci and decrease lung metastases and prolong lifespan in mouse tumor model through inducing anti-angiogenesis and apoptosis in tumors. Conclusion We demonstrated that BMSCs might be employed as a promising vehicle for tumor gene therapy which can effectively not only improve the concentration of anticancer therapeutics in tumors, but also modify the tumor microenvironment.

Lanthanide-organic frameworks constructed from multi-functional ligands: Syntheses, structures, near-infrared and visible photoluminescence properties

International Nuclear Information System (INIS)

Li Xinfa; Xie Zailai; Lin Jingxiang; Cao Rong

2009-01-01

A series of multi-functional ligands supported lanthanide-organic frameworks, formulated as [Ln(HL 1 )(H 2 L 2 ) 0.5 (H 4 L 2 ) 0.5 (H 2 O)].(H 2 O) 1.5 .{Ln=La (1), Pr (2), Nd (3), Sm (4), Eu (5); H 3 L 1 =5-Sulfosaclicylic acid; H 4 L 2 =N,N'-piperazine (bis-methylene phosphonic acid)}, have been synthesized by hydrothermal reactions. Single crystal X-ray diffractions and powder XRD patterns confirm they are isostructural. They feature 3D framework structures based on extension of a 'zigzag' inorganic chain by organic linkers. Moreover, the photoluminescence properties of 5 and 3 have been investigated, and they show strong solid-state emissions in the visible and near-infrared (IR) regions at room temperature. - Graphical abstract: Five multi-functional ligands supported 3D lanthanide-organic frameworks have been synthesized and structurally characterized. Compounds 5 and 3 displayed strong solid-state emissions in the visible and near-infrared region at room temperature.

Virtual screening using the ligand ZINC database for novel lipoxygenase-3 inhibitors.

Science.gov (United States)

Monika; Kour, Janmeet; Singh, Kulwinder

2013-01-01

The leukotrienes constitute a group of arachidonic acid-derived compounds with biologic activities suggesting important roles in inflammation and immediate hypersensitivity. Epidermis-type lipoxygenase-3 (ALOXE3), a distinct subclass within the multigene family of mammalian lipoxygenases, is a novel isoenzyme involved in the metabolism of leukotrienes and plays a very important role in skin barrier functions. Lipoxygenase selective inhibitors such as azelastine and zileuton are currently used to reduce inflammatory response. Nausea, pharyngolaryngeal pain, headache, nasal burning and somnolence are the most frequently reported adverse effects of these drugs. Therefore, there is still a need to develop more potent lipoxygenase inhibitors. In this paper, we report the screening of various compounds from the ZINC database (contains over 21 million compounds) using the Molegro Virtual Docker software against the ALOXE3 protein. Screening was performed using molecular constraints tool to filter compounds with physico-chemical properties similar to the 1N8Q bound ligand protocatechuic acid. The analysis resulted in 4319 Lipinski compliant hits which are docked and scored to identify structurally novel ligands that make similar interactions to those of known ligands or may have different interactions with other parts of the binding site. Our screening approach identified four molecules ZINC84299674; ZINC76643455; ZINC84299122 & ZINC75626957 with MolDock score of -128.901, -120.22, -116.873 & - 102.116 kcal/mol, respectively. Their energy scores were better than the 1N8Q bound co-crystallized ligand protocatechuic acid (with MolDock score of -77.225 kcal/mol). All the ligands were docked within the binding pocket forming interactions with amino acid residues.

The role of HOXB2 and HOXB3 in acute myeloid leukemia

Energy Technology Data Exchange (ETDEWEB)

Lindblad, Oscar [Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund (Sweden); Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund (Sweden); Department of Hematology and Vascular Disorders, Skåne University Hospital, Lund (Sweden); Chougule, Rohit A.; Moharram, Sausan A. [Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund (Sweden); Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund (Sweden); Kabir, Nuzhat N. [Laboratory of Computational Biochemistry, KN Biomedical Research Institute, Barisal (Bangladesh); Sun, Jianmin [Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund (Sweden); Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund (Sweden); Kazi, Julhash U. [Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund (Sweden); Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund (Sweden); Laboratory of Computational Biochemistry, KN Biomedical Research Institute, Barisal (Bangladesh); Rönnstrand, Lars, E-mail: lars.ronnstrand@med.lu.se [Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund (Sweden); Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, Lund (Sweden)

2015-11-27

Acute myeloid leukemia (AML) is a heterogeneous aggressive disease and the most common form of adult leukemia. Mutations in the type III receptor tyrosine kinase FLT3 are found in more than 30% of AML patients. Drugs against FLT3 have been developed for the treatment of AML, but they lack specificity, show poor response and lead to the development of a resistant phenotype upon treatment. Therefore, a deeper understanding of FLT3 signaling will facilitate identification of additional pharmacological targets in FLT3-driven AML. In this report, we identify HOXB2 and HOXB3 as novel regulators of oncogenic FLT3-ITD-driven AML. We show that HOXB2 and HOXB3 expression is upregulated in a group of AML patients carrying FLT3-ITD. Overexpression of HOXB2 or HOXB3 in mouse pro-B cells resulted in decreased FLT3-ITD-dependent cell proliferation as well as colony formation and increased apoptosis. Expression of HOXB2 or HOXB3 resulted in a significant decrease in FLT3-ITD-induced AKT, ERK, p38 and STAT5 phosphorylation. Our data suggest that HOXB2 and HOXB3 act as tumor suppressors in FLT3-ITD driven AML.

A pilot study for texture analysis of {sup 18}F-FDG and {sup 18}F-FLT-PET/CT to predict tumor recurrence of patients with colorectal cancer who received surgery

Energy Technology Data Exchange (ETDEWEB)

Nakajo, Masatoyo; Tani, Atsushi; Jinguji, Megumi; Yoshiura, Takashi [Kagoshima University, Department of Radiology, Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Kajiya, Yoriko; Nakajo, Masayuki [Nanpuh Hospital, Department of Radiology, Kagoshima (Japan); Kitazono, Masaki [Nanpuh Hospital, Department of Surgery, Kagoshima (Japan)

2017-12-15

This retrospective study was done to examine whether the heterogeneity in primary tumor F-18-fluorodeoxyglucose ({sup 18}F-FDG) and {sup 18}F-3'-fluoro-3'-deoxythymidine ({sup 18}F-FLT) distribution can predict prognosis of patients with colorectal cancer who received surgery. The enrolled 32 patients with colorectal cancer underwent both {sup 18}F-FDG- and {sup 18}F-FLT-PET/CT studies before surgery. Clinicopathological factors, stage, SUVmax, SUVmean, metabolic tumor volume (SUV ≥ 2.5), total lesion glycolysis, total lesion proliferation and seven texture heterogeneity parameters (coefficient of variation, local parameters: entropy, homogeneity, and dissimilarity; and regional parameters: intensity variability [IV], size-zone variability [SZV], and zone percentage [ZP]) were obtained. Progression free survival (PFS) was calculated by the Kaplan-Meier method. Prognostic significance was assessed by Cox proportional hazards analysis. Eight patients had eventually come to progression, and 24 patients were alive without progression during clinical follow-up [mean follow-up PFS; 55.9 months (range, 1-72)]. High stage (p = 0.004), high {sup 18}F-FDG-IV (p = 0.015), high {sup 18}F-FDG-SZV (p = 0.013) and high {sup 18}F-FLT-entropy (p = 0.015) were significant in predicting poor 5-year PFS. Other parameters did not predict the disease outcome. At bivariate analysis, disease event hazards ratios for {sup 18}F-FDG-IV and {sup 18}F-FDG-SZV remained significant when adjusted for stage and {sup 18}F-FLT-entropy ({sup 18}F-FDG-IV; p = 0.004 [adjusted for stage], 0.007 [adjusted for {sup 18}F-FLT-entropy]; {sup 18}F-FDG-SZV; p = 0.028 [adjusted for stage], 0.040 [adjusted for {sup 18}F-FLT-entropy]). {sup 18}F-FDG PET heterogeneity parameters, IV and SZV, have a potential to be strong prognostic factors to predict PFS of patients with surgically resected colorectal cancer and are more useful than {sup 18}F-FLT-PET/CT heterogeneity parameters. (orig.)

CMPO-functionalized C{sub 3}-symmetric tripodal ligands in liquid/liquid extractions : efficient, selective recognition of Pu(IV) with low affinity for 3+ metal ions.

Energy Technology Data Exchange (ETDEWEB)

Matloka, K.; Sah, A. K.; Peters, M. W.; Srinivasan, P.; Gelis, A. V.; Regalbuto, M.; Scott, M. J.; Univ. of Florida

2007-12-10

Structural modifications of carbamoylmethylphosphine oxide (CPMO)-functionalized triphenoxymethane platforms are described, and the influence of these changes on the ability of the ligand to extract actinides from simulated acidic nuclear waste streams has been evaluated. The ligand system has been shown to have excellent binding efficiency and a selectivity for An(IV) in comparison to the a simple monomeric CMPO ligand under analogous conditions. Both the extraction efficiency and selectivity are strongly dependent on the flexibility and electronic properties of the ligating units in the triphenoxymethane construct. The Tb(III) and Bi(III) nitrate complexes of tris-CMPO derivatives have been isolated, and their structures were elucidated by NMR, ESI FT-ICR MS, and X-ray analysis, providing information on the interactions between metal ions and the tris-CMPO molecules.

Predicting location of recurrence using FDG, FLT, and Cu-ATSM PET in canine sinonasal tumors treated with radiotherapy

International Nuclear Information System (INIS)

Bradshaw, Tyler; Jeraj, Robert; Fu, Rau; Zhu, Jun; Bowen, Stephen; Forrest, Lisa

2015-01-01

Dose painting relies on the ability of functional imaging to identify resistant tumor subvolumes to be targeted for additional boosting. This work assessed the ability of FDG, FLT, and Cu-ATSM PET imaging to predict the locations of residual FDG PET in canine tumors following radiotherapy. Nineteen canines with spontaneous sinonasal tumors underwent PET/CT imaging with radiotracers FDG, FLT, and Cu-ATSM prior to hypofractionated radiotherapy. Therapy consisted of 10 fractions of 4.2 Gy to the sinonasal cavity with or without an integrated boost of 0.8 Gy to the GTV. Patients had an additional FLT PET/CT scan after fraction 2, a Cu-ATSM PET/CT scan after fraction 3, and follow-up FDG PET/CT scans after radiotherapy. Following image registration, simple and multiple linear and logistic voxel regressions were performed to assess how well pre- and mid-treatment PET imaging predicted post-treatment FDG uptake. R 2 and pseudo R 2 were used to assess the goodness of fits. For simple linear regression models, regression coefficients for all pre- and mid-treatment PET images were significantly positive across the population (P < 0.05). However, there was large variability among patients in goodness of fits: R 2 ranged from 0.00 to 0.85, with a median of 0.12. Results for logistic regression models were similar. Multiple linear regression models resulted in better fits (median R 2 = 0.31), but there was still large variability between patients in R 2 . The R 2 from regression models for different predictor variables were highly correlated across patients (R ≈ 0.8), indicating tumors that were poorly predicted with one tracer were also poorly predicted by other tracers. In conclusion, the high inter-patient variability in goodness of fits indicates that PET was able to predict locations of residual tumor in some patients, but not others. This suggests not all patients would be good candidates for dose painting based on a single biological target. (paper)

Evaluation of several two-step scoring functions based on linear interaction energy, effective ligand size, and empirical pair potentials for prediction of protein-ligand binding geometry and free energy.

Science.gov (United States)

Rahaman, Obaidur; Estrada, Trilce P; Doren, Douglas J; Taufer, Michela; Brooks, Charles L; Armen, Roger S

2011-09-26

The performances of several two-step scoring approaches for molecular docking were assessed for their ability to predict binding geometries and free energies. Two new scoring functions designed for "step 2 discrimination" were proposed and compared to our CHARMM implementation of the linear interaction energy (LIE) approach using the Generalized-Born with Molecular Volume (GBMV) implicit solvation model. A scoring function S1 was proposed by considering only "interacting" ligand atoms as the "effective size" of the ligand and extended to an empirical regression-based pair potential S2. The S1 and S2 scoring schemes were trained and 5-fold cross-validated on a diverse set of 259 protein-ligand complexes from the Ligand Protein Database (LPDB). The regression-based parameters for S1 and S2 also demonstrated reasonable transferability in the CSARdock 2010 benchmark using a new data set (NRC HiQ) of diverse protein-ligand complexes. The ability of the scoring functions to accurately predict ligand geometry was evaluated by calculating the discriminative power (DP) of the scoring functions to identify native poses. The parameters for the LIE scoring function with the optimal discriminative power (DP) for geometry (step 1 discrimination) were found to be very similar to the best-fit parameters for binding free energy over a large number of protein-ligand complexes (step 2 discrimination). Reasonable performance of the scoring functions in enrichment of active compounds in four different protein target classes established that the parameters for S1 and S2 provided reasonable accuracy and transferability. Additional analysis was performed to definitively separate scoring function performance from molecular weight effects. This analysis included the prediction of ligand binding efficiencies for a subset of the CSARdock NRC HiQ data set where the number of ligand heavy atoms ranged from 17 to 35. This range of ligand heavy atoms is where improved accuracy of predicted ligand

Ligand-Enabled γ-C(sp3)–H Olefination of Amines: En Route to Pyrrolidines

Science.gov (United States)

Jiang, Heng; He, Jian; Liu, Tao

2016-01-01

Pd(II)-catalyzed olefination of γ-C(sp3)–H bonds of triflyl (Tf) and 4-nitrobenzenesulfonyl (Ns) protected amines is achieved. Subsequent aza-Wacker oxidative cyclization or conjugate addition of the olefinated intermediates provides a variety of C-2 alkylated pyrrolidines. Three pyridine- and quinoline-based ligands are developed to match different classes of amine substrates, demonstrating a rare example of ligand-enabled C(sp3)–H olefination reaction. The use of Ns protecting group to direct C(sp3)–H activation of alkyl amine is also a significant step towards practical C–H functionalizations of alkyl amines. PMID:26796676

Use of Molecular Imaging Markers of Glycolysis, Hypoxia and Proliferation (18F-FDG, 64Cu-ATSM and 18F-FLT) in a Dog with Fibrosarcoma

DEFF Research Database (Denmark)

Zornhagen, Kamilla; Clausen, Malene; Hansen, Anders Elias

2015-01-01

of cancer patients. A dog with fibrosarcoma was imaged using 18F-FDG, 64Cu-ATSM, and 18F-FLT before, during, and after 10 fractions of 4.5 Gy radiotherapy. Uptake of all tracers decreased during treatment. Fluctuations in 18F-FDG and 18F-FLT PET uptakes and a heterogeneous spatial distribution of the three......Glycolysis, hypoxia, and proliferation are important factors in the tumor microenvironment contributing to treatment-resistant aggressiveness. Imaging these factors using combined functional positron emission tomography and computed tomography can potentially guide diagnosis and management...... tracers were seen. Tracer distributions partially overlapped. It appears that each tracer provides distinct information about tumor heterogeneity and treatment response....

Regulation of Stat5 by FAK and PAK1 in Oncogenic FLT3 and KIT driven Leukemogenesis

Science.gov (United States)

Chatterjee, Anindya; Ghosh, Joydeep; Ramdas, Baskar; Mali, Raghuveer Singh; Martin, Holly; Kobayashi, Michihiro; Vemula, Sasidhar; Canela, Victor H.; Waskow, Emily R.; Visconte, Valeria; Tiu, Ramon V.; Smith, Catherine C.; Shah, Neil; Bunting, Kevin D.; Boswell, H. Scott; Liu, Yan; Chan, Rebecca J.; Kapur, Reuben

2015-01-01

SUMMARY Oncogenic mutations of FLT3 and KIT receptors are associated with poor survival in patients with acute myeloid leukemia (AML) and myeloproliferative neoplasms (MPN) and currently available drugs are largely ineffective. Although Stat5 has been implicated in regulating several myeloid and lymphoid malignancies, how precisely Stat5 regulates leukemogenesis, including its nuclear translocation to induce gene transcription is poorly understood. In leukemic cells, we show constitutive activation of focal adhesion kinase (FAK), whose inhibition represses leukemogenesis. Downstream of FAK, activation of Rac1 is regulated by RacGEF Tiam1, whose inhibition prolongs the survival of leukemic mice. Inhibition of the Rac1 effector PAK1 prolongs the survival of leukemic mice in part by inhibiting the nuclear translocation of Stat5. These results reveal a leukemic pathway involving FAK/Tiam1/Rac1/PAK1 and demonstrate an essential role for these signaling molecules in regulating the nuclear translocation of Stat5 in leukemogenesis. PMID:25456130

Regulation of Stat5 by FAK and PAK1 in Oncogenic FLT3- and KIT-Driven Leukemogenesis

Directory of Open Access Journals (Sweden)

Anindya Chatterjee

2014-11-01

Full Text Available Oncogenic mutations of FLT3 and KIT receptors are associated with poor survival in patients with acute myeloid leukemia (AML and myeloproliferative neoplasms (MPNs, and currently available drugs are largely ineffective. Although Stat5 has been implicated in regulating several myeloid and lymphoid malignancies, how precisely Stat5 regulates leukemogenesis, including its nuclear translocation to induce gene transcription, is poorly understood. In leukemic cells, we show constitutive activation of focal adhesion kinase (FAK whose inhibition represses leukemogenesis. Downstream of FAK, activation of Rac1 is regulated by RacGEF Tiam1, whose inhibition prolongs the survival of leukemic mice. Inhibition of the Rac1 effector PAK1 prolongs the survival of leukemic mice in part by inhibiting the nuclear translocation of Stat5. These results reveal a leukemic pathway involving FAK/Tiam1/Rac1/PAK1 and demonstrate an essential role for these signaling molecules in regulating the nuclear translocation of Stat5 in leukemogenesis.

Reaction of Non-Symmetric Schiff Base Metallo-Ligand Complexes Possessing an Oxime Function with Ln Ions

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Jean-Pierre Costes

2018-03-01

Full Text Available The preparation of non-symmetric Schiff base ligands possessing one oxime function that is associated to a second function such as pyrrole or phenol function is first described. These ligands, which possess inner N4 or N3O coordination sites, allow formation of cationic or neutral non-symmetric CuII or NiII metallo-ligand complexes under their mono- or di-deprotonated forms. In presence of Lanthanide ions the neutral complexes do not coordinate to the LnIII ions, the oxygen atom of the oxime function being only hydrogen-bonded to a water molecule that is linked to the LnIII ion. This surprising behavior allows for the isolation of LnIII ions by non-interacting metal complexes. Reaction of cationic NiII complexes possessing a protonated oxime function with LnIII ions leads to the formation of original and dianionic (Gd(NO352− entities that are well separated from each other. This work highlights the preparation of well isolated mononuclear LnIII entities into a matrix of diamagnetic metal complexes. These new complexes complete our previous work dealing with the complexing ability of the oxime function toward Lanthanide ions. It could open the way to the synthesis of new entities with interesting properties, such as single-ion magnets for example.

The effect of prenatal pravastatin treatment on altered fetal programming of postnatal growth and metabolic function in a preeclampsia-like murine model.

Science.gov (United States)

McDonnold, Mollie; Tamayo, Esther; Kechichian, Talar; Gamble, Phyllis; Longo, Monica; Hankins, Gary D V; Saade, George R; Costantine, Maged M

2014-06-01

Preeclampsia alters fetal programming and results in long-term metabolic consequences in the offspring. Pravastatin has been shown to prevent preeclampsia in animal models. Our aim was to characterize the effects of preeclampsia on fetal programming of adult growth and metabolic function, and evaluate the role of preventive pravastatin therapy, using a well characterized murine model. CD-1 mice were injected through the tail vein with adenovirus carrying soluble fms-like tyrosine kinase 1 (sFlt-1) and randomly allocated to pravastatin (5 mg/kg/day; sFlt-1/prav, n = 7) or water (sFlt-1, n = 6) until weaning. A control group was injected with adenovirus carrying the murine immunoglobulin G2α Fc fragment (mFc, n = 8). Male and female offspring (6-8/group) were weighed every month until 6 months of age. Intraperitoneal glucose tolerance testing was performed after 16 hours of fasting at 3 and 6 months of age; glucose and insulin responses were measured. sFlt-1 offspring weight was lower than mFc control (P < .001) until 2 months of age for females and 5 months of age for males (P < .001). There were no differences in postnatal growth between mFc and sFlt-1/prav offspring. At 3 and 6 months, female sFlt-1 offspring had higher glucose response compared with mFc and sFlt-1/prav. Three-month-old male sFlt-1 had lower insulin response compared with mFc offspring. Preeclampsia alters postnatal growth and metabolic function in the adult offspring in this animal model. Maternal therapy with prav prevents some of these alterations in the offspring. Copyright © 2014 Mosby, Inc. All rights reserved.

Dopamine D3 receptor ligands for drug addiction treatment: update on recent findings.

Science.gov (United States)

Le Foll, Bernard; Collo, Ginetta; Rabiner, Eugenii A; Boileau, Isabelle; Merlo Pich, Emilio; Sokoloff, Pierre

2014-01-01

The dopamine D3 receptor is located in the limbic area and apparently mediates selective effects on motivation to take drugs and drug-seeking behaviors, so that there has been considerable interest on the possible use of D3 receptor ligands to treat drug addiction. However, only recently selective tools allowing studying this receptor have been developed. This chapter presents an overview of findings that were presented at a symposium on the conference Dopamine 2013 in Sardinia in May 2013. Novel neurobiological findings indicate that drugs of abuse can lead to significant structural plasticity in rodent brain and that this is dependent on the availability of functional dopamine D3 autoreceptor, whose activation increased phosphorylation in the ERK pathway and in the Akt/mTORC1 pathway indicating the parallel engagement of a series of intracellular signaling pathways all involved in cell growth and survival. Preclinical findings using animal models of drug-seeking behaviors confirm that D3 antagonists have a promising profile to treat drug addiction across drugs of abuse type. Imaging the D3 is now feasible in human subjects. Notably, the development of (+)-4-propyl-9-hydroxynaphthoxazine ligand used in positron emission tomography (PET) studies in humans allows to measure D3 and D2 receptors based on the area of the brain under study. This PET ligand has been used to confirm up-regulation of D3 sites in psychostimulant users and to reveal that tobacco smoking produces elevation of dopamine at the level of D3 sites. There are now novel antagonists being developed, but also old drugs such as buspirone, that are available to test the D3 hypothesis in humans. The first results of clinical investigations are now being provided. Overall, those recent findings support further exploration of D3 ligands to treat drug addiction. © 2014 Elsevier B.V. All rights reserved.

Effect of p53 activation on cell growth, thymidine kinase-1 activity, and 3'-deoxy-3'fluorothymidine uptake

International Nuclear Information System (INIS)

Schwartz, Jeffrey L.; Tamura, Yasuko; Jordan, Robert; Grierson, John R.; Krohn, Kenneth A.

2004-01-01

The use of thymidine (TdR) and thymidine analogs such as 3'-deoxy-3'-fluorothymidine (FLT) as positron emission tomography (PET)-based tracers of tumor proliferation rate is based on the hypothesis that measurement of uptake of these nucleosides, a function primarily of thymidine kinase-1 (TK 1 ) activity, provides an accurate measure of cell proliferation in tumors. Tumor growth is influenced by many factors including the oxygen concentration within tumors and whether tumor cells have been exposed to cytotoxic therapies. The p53 gene plays an important role in regulating growth under both of these conditions. The goal of this study was to investigate the influence of p53 activation on cell growth, TK 1 activity, and FLT uptake. To accomplish this, TK 1 activity, S phase fraction, and the uptake of FLT were determined in plateau-phase and exponentially growing cultures of an isogenic pair of human tumor cell lines in which p53 expression was normal or inactivated by human papilloma virus type 16 E6 expression. Ionizing radiation exposure was used to stimulate p53 activity and to induce alterations in cell cycle progression. We found that exposure of cells to ionizing radiation induced dose-dependent changes in cell cycle progression in both cell lines. The relationship between S phase percentage, TK 1 activity, and FLT uptake were essentially unchanged in the p53-normal cell line. In contrast, TK 1 activity and FLT uptake remained high in the p53-deficient variant even when S phase percentage was low due to a p53-dependent G2 arrest. We conclude that a functional p53 response is required to maintain the normal relationship between TK1 activity and S phase percentage following radiation exposure

Adsorption of hairy particles with mobile ligands: Molecular dynamics and density functional study

Science.gov (United States)

Borówko, M.; Sokołowski, S.; Staszewski, T.; Pizio, O.

2018-01-01

We study models of hairy nanoparticles in contact with a hard wall. Each particle is built of a spherical core with a number of ligands attached to it and each ligand is composed of several spherical, tangentially jointed segments. The number of segments is the same for all ligands. Particular models differ by the numbers of ligands and of segments per ligand, but the total number of segments is constant. Moreover, our model assumes that the ligands are tethered to the core in such a manner that they can "slide" over the core surface. Using molecular dynamics simulations we investigate the differences in the structure of a system close to the wall. In order to characterize the distribution of the ligands around the core, we have calculated the end-to-end distances of the ligands and the lengths and orientation of the mass dipoles. Additionally, we also employed a density functional approach to obtain the density profiles. We have found that if the number of ligands is not too high, the proposed version of the theory is capable to predict the structure of the system with a reasonable accuracy.

Visualization of endothelial cell cycle dynamics in mouse using the Flt-1/eGFP-anillin system.

Science.gov (United States)

Herz, Katia; Becker, Alexandra; Shi, Chenyue; Ema, Masatsugo; Takahashi, Satoru; Potente, Michael; Hesse, Michael; Fleischmann, Bernd K; Wenzel, Daniela

2018-05-01

Endothelial cell proliferation is a key process during vascular growth but its kinetics could only be assessed in vitro or ex vivo so far. To enable the monitoring and quantification of cell cycle kinetics in vivo, we have generated transgenic mice expressing an eGFP-anillin construct under control of the endothelial-specific Flt-1 promoter. This construct labels the nuclei of endothelial cells in late G1, S and G2 phase and changes its localization during the different stages of M phase, thereby enabling the monitoring of EC proliferation and cytokinesis. In Flt-1/eGFP-anillin mice, we found eGFP + signals specifically in Ki67 + /PECAM + endothelial cells during vascular development. Quantification using this cell cycle reporter in embryos revealed a decline in endothelial cell proliferation between E9.5 to E12.5. By time-lapse microscopy, we determined the length of different cell cycle phases in embryonic endothelial cells in vivo and found a M phase duration of about 80 min with 2/3 covering karyokinesis and 1/3 cytokinesis. Thus, we have generated a versatile transgenic system for the accurate assessment of endothelial cell cycle dynamics in vitro and in vivo.

Alterations in plasma soluble vascular endothelial growth factor receptor-1 (sFlt-1 concentrations during coronary artery bypass graft surgery: relationships with post-operative complications

Directory of Open Access Journals (Sweden)

Orsel Isabelle

2008-04-01

Full Text Available Abstract Background Plasma concentrations of sFlt-1, the soluble form of the vascular endothelial growth factor receptor (VEGF, markedly increase during coronary artery bypass graft (CABG surgery with extracorporeal circulation (ECC. We investigated if plasma sFlt-1 values might be related to the occurrence of surgical complications after CABG. Methods Plasma samples were collected from the radial artery catheter before vascular cannulation and after opening the chest, at the end of ECC just before clamp release, after cross release, after weaning from ECC, at the 6th and 24th post-operative hour. Thirty one patients were investigated. The presence of cardiovascular, haematological and respiratory dysfunctions was prospectively assessed. Plasma sFlt-1 levels were measured with commercially ELISA kits. Results Among the 31 investigated patients, 15 had uneventful surgery. Patients with and without complications had similar pre-operative plasma sFlt-1 levels. Lowered plasma sFlt-1 levels were observed at the end of ECC in patients with haematological (p = 0.001, ANOVA or cardiovascular (p = 0.006 impairments, but not with respiratory ones (p = 0.053, as compared to patients with uneventful surgery. Conclusion These results identify an association between specific post-CABG complication and the lower release of sFlt-1 during ECC. sFlt-1-induced VEGF neutralisation might, thus, be beneficial to reduce the development of post-operative adverse effects after CABG.

Ligand-accelerated non-directed C-H functionalization of arenes

Science.gov (United States)

Wang, Peng; Verma, Pritha; Xia, Guoqin; Shi, Jun; Qiao, Jennifer X.; Tao, Shiwei; Cheng, Peter T. W.; Poss, Michael A.; Farmer, Marcus E.; Yeung, Kap-Sun; Yu, Jin-Quan

2017-11-01

The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.

Accounting for Intraligand Interactions in Flexible Ligand Docking with a PMF-Based Scoring Function.

Science.gov (United States)

Lizunov, A Y; Gonchar, A L; Zaitseva, N I; Zosimov, V V

2015-10-26

We analyzed the frequency with which intraligand contacts occurred in a set of 1300 protein-ligand complexes [ Plewczynski et al. J. Comput. Chem. 2011 , 32 , 742 - 755 .]. Our analysis showed that flexible ligands often form intraligand hydrophobic contacts, while intraligand hydrogen bonds are rare. The test set was also thoroughly investigated and classified. We suggest a universal method for enhancement of a scoring function based on a potential of mean force (PMF-based score) by adding a term accounting for intraligand interactions. The method was implemented via in-house developed program, utilizing an Algo_score scoring function [ Ramensky et al. Proteins: Struct., Funct., Genet. 2007 , 69 , 349 - 357 .] based on the Tarasov-Muryshev PMF [ Muryshev et al. J. Comput.-Aided Mol. Des. 2003 , 17 , 597 - 605 .]. The enhancement of the scoring function was shown to significantly improve the docking and scoring quality for flexible ligands in the test set of 1300 protein-ligand complexes [ Plewczynski et al. J. Comput. Chem. 2011 , 32 , 742 - 755 .]. We then investigated the correlation of the docking results with two parameters of intraligand interactions estimation. These parameters are the weight of intraligand interactions and the minimum number of bonds between the ligand atoms required to take their interaction into account.

IgG-Fc-mediated effector functions: molecular definition of interaction sites for effector ligands and the role of glycosylation.

Science.gov (United States)

Jefferis, R; Lund, J; Pound, J D

1998-06-01

The Fc region of human IgG expresses interaction sites for many effector ligands. In this review the topographical distributions of ten of these sites are discussed in relation to functional requirement. It is apparent that interaction sites localised to the inter-CH2-CH3 domain region of the Fc allow for functional divalency, whereas sites localised to the hinge proximal region of the CH2 domain are functionally monovalent, with expression of the latter sites being particularly dependent on glycosylation. All x-ray crystal structures for Fc and Fc-ligand complexes report that the protein structure of the hinge proximal region of the CH2 domain is "disordered", suggesting "internal mobility". We propose a model in which such "internal mobility" results in the generation of a dynamic equilibrium between multiple conformers, certain of which express interaction sites specific to individual ligands. The emerging understanding of the influence of oligosaccharide/protein interactions on protein conformation and biological function of IgG antibodies suggests a potential to generate novel glycoforms of antibody molecules having unique profiles of effector functions.

AutoSite: an automated approach for pseudo-ligands prediction—from ligand-binding sites identification to predicting key ligand atoms

Science.gov (United States)

Ravindranath, Pradeep Anand; Sanner, Michel F.

2016-01-01

Motivation: The identification of ligand-binding sites from a protein structure facilitates computational drug design and optimization, and protein function assignment. We introduce AutoSite: an efficient software tool for identifying ligand-binding sites and predicting pseudo ligand corresponding to each binding site identified. Binding sites are reported as clusters of 3D points called fills in which every point is labelled as hydrophobic or as hydrogen bond donor or acceptor. From these fills AutoSite derives feature points: a set of putative positions of hydrophobic-, and hydrogen-bond forming ligand atoms. Results: We show that AutoSite identifies ligand-binding sites with higher accuracy than other leading methods, and produces fills that better matches the ligand shape and properties, than the fills obtained with a software program with similar capabilities, AutoLigand. In addition, we demonstrate that for the Astex Diverse Set, the feature points identify 79% of hydrophobic ligand atoms, and 81% and 62% of the hydrogen acceptor and donor hydrogen ligand atoms interacting with the receptor, and predict 81.2% of water molecules mediating interactions between ligand and receptor. Finally, we illustrate potential uses of the predicted feature points in the context of lead optimization in drug discovery projects. Availability and Implementation: http://adfr.scripps.edu/AutoDockFR/autosite.html Contact: sanner@scripps.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27354702

Photochemical Properties and Reactivity of a Ru Compound Containing an NAD/NADH-Functionalized 1,10-Phenanthroline Ligand.

Science.gov (United States)

Kobayashi, Katsuaki; Ohtsu, Hideki; Nozaki, Koichi; Kitagawa, Susumu; Tanaka, Koji

2016-03-07

An NAD/NADH-functionalized ligand, benzo[b]pyrido[3,2-f][1,7]-phenanthroline (bpp), was newly synthesized. A Ru compound containing the bpp ligand, [Ru(bpp)(bpy)2](2+), underwent 2e(-) and 2H(+) reduction, generating the NADH form of the compound, [Ru(bppHH)(bpy)2](2+), in response to visible light irradiation in CH3CN/TEA/H2O (8/1/1). The UV-vis and fluorescent spectra of both [Ru(bpp)(bpy)2](2+) and [Ru(bppHH)(bpy)2](2+) resembled the spectra of [Ru(bpy)3](2+). Both complexes exhibited strong emission, with quantum yields of 0.086 and 0.031, respectively; values that are much higher than those obtained from the NAD/NADH-functionalized complexes [Ru(pbn)(bpy)2](2+) and [Ru(pbnHH)(bpy)2](2+) (pbn = (2-(2-pyridyl)benzo[b]-1.5-naphthyridine, pbnHH = hydrogenated form of pbn). The reduction potential of the bpp ligand in [Ru(bpp)(bpy)2](2+) (-1.28 V vs SCE) is much more negative than that of the pbn ligand in [Ru(pbn)(bpy)2](2+) (-0.74 V), although the oxidation potentials of bppHH and pbnHH are essentially equal (0.95 V). These results indicate that the electrochemical oxidation of the dihydropyridine moiety in the NADH-type ligand was independent of the π system, including the Ru polypyridyl framework. [Ru(bppHH)(bpy)2](2+) allowed the photoreduction of oxygen, generating H2O2 in 92% yield based on [Ru(bppHH)(bpy)2](2+). H2O2 production took place via singlet oxygen generated by the energy transfer from excited [Ru(bppHH)(bpy)2](2+) to triplet oxygen.

Effect of p53 activation on cell growth, thymidine kinase-1 activity, and 3'-deoxy-3'fluorothymidine uptake

Energy Technology Data Exchange (ETDEWEB)

Schwartz, Jeffrey L. E-mail: jschwart@u.washington.edu; Tamura, Yasuko; Jordan, Robert; Grierson, John R.; Krohn, Kenneth A

2004-05-01

The use of thymidine (TdR) and thymidine analogs such as 3'-deoxy-3'-fluorothymidine (FLT) as positron emission tomography (PET)-based tracers of tumor proliferation rate is based on the hypothesis that measurement of uptake of these nucleosides, a function primarily of thymidine kinase-1 (TK{sub 1}) activity, provides an accurate measure of cell proliferation in tumors. Tumor growth is influenced by many factors including the oxygen concentration within tumors and whether tumor cells have been exposed to cytotoxic therapies. The p53 gene plays an important role in regulating growth under both of these conditions. The goal of this study was to investigate the influence of p53 activation on cell growth, TK{sub 1} activity, and FLT uptake. To accomplish this, TK{sub 1} activity, S phase fraction, and the uptake of FLT were determined in plateau-phase and exponentially growing cultures of an isogenic pair of human tumor cell lines in which p53 expression was normal or inactivated by human papilloma virus type 16 E6 expression. Ionizing radiation exposure was used to stimulate p53 activity and to induce alterations in cell cycle progression. We found that exposure of cells to ionizing radiation induced dose-dependent changes in cell cycle progression in both cell lines. The relationship between S phase percentage, TK{sub 1} activity, and FLT uptake were essentially unchanged in the p53-normal cell line. In contrast, TK{sub 1} activity and FLT uptake remained high in the p53-deficient variant even when S phase percentage was low due to a p53-dependent G2 arrest. We conclude that a functional p53 response is required to maintain the normal relationship between TK1 activity and S phase percentage following radiation exposure.

Reversibly Switchable, pH-Dependent Peptide Ligand Binding via 3,5-Diiodotyrosine Substitutions.

Science.gov (United States)

Ngambenjawong, Chayanon; Sylvestre, Meilyn; Gustafson, Heather H; Pineda, Julio Marco B; Pun, Suzie H

2018-04-20

Cell type-specific targeting ligands utilized in drug delivery applications typically recognize receptors that are overexpressed on the cells of interest. Nonetheless, these receptors may also be expressed, to varying extents, on off-target cells, contributing to unintended side effects. For the selectivity profile of targeting ligands in cancer therapy to be improved, stimuli-responsive masking of these ligands with acid-, redox-, or enzyme-cleavable molecules has been reported, whereby the targeting ligands are exposed in specific environments, e.g., acidic tumor hypoxia. One possible drawback of these systems lies in their one-time, permanent trigger, which enables the "demasked" ligands to bind off-target cells if released back into the systemic circulation. A promising strategy to address the aforementioned problem is to design ligands that show selective binding based on ionization state, which may be microenvironment-dependent. In this study, we report a systematic strategy to engineer low pH-selective targeting peptides using an M2 macrophage-targeting peptide (M2pep) as an example. 3,5-Diiodotyrosine mutagenesis into native tyrosine residues of M2pep confers pH-dependent binding behavior specific to acidic environment (pH 6) when the amino acid is protonated into the native tyrosine-like state. At physiological pH of 7.4, the hydroxyl group of 3,5-diiodotyrosine on the peptide is deprotonated leading to interruption of the peptide native binding property. Our engineered pH-responsive M2pep (Ac-Y-Î-Î) binds target M2 macrophages more selectively at pH 6 than at pH 7.4. In addition, 3,5-diiodotyrosine substitutions also improve serum stability of the peptide. Finally, we demonstrate pH-dependent reversibility in target binding via a postbinding peptide elution study. The strategy presented here should be applicable for engineering pH-dependent functionality of other targeting peptides with potential applications in physiology-dependent in vivo targeting

Soluble NKG2D ligands: prevalence, release, and functional impact.

Science.gov (United States)

Salih, Helmut Rainer; Holdenrieder, Stefan; Steinle, Alexander

2008-05-01

Natural Killer (NK) cells are capable to recognize and eliminate malignant cells. Anti-tumor responses of NK cells are promoted by the tumor-associated expression of cell stress-inducible ligands of the activating NK receptor NKG2D. Current evidence suggests that established tumors subvert NKG2D-mediated tumor immunosurveillance by releasing NKG2D ligands (NKG2DL). Release of NKG2DL has been observed in a broad variety of human tumor entities and is thought to interfere with NKG2D-mediated tumor immunity in several ways. Further, levels of soluble NKG2DL (sNKG2DL) were also found to be elevated under various non-malignant conditions, although the functional implications remain largely unclear. Here we review and discuss the available data on the prevalence, release, functional impact, and potential clinical value of sNKG2DL.

Can multimodality imaging using {sup 18}F-FDG/{sup 18}F-FLT PET/CT benefit the diagnosis and management of patients with pulmonary lesions?

Energy Technology Data Exchange (ETDEWEB)

Xu, Baixuan; Guan, Zhiwei; Liu, Changbin; Wang, Ruimin; Yin, Dayi; Zhang, Jinming; Chen, Yingmao; Yao, Shulin; Shao, Mingzhe; Wang, Hui; Tian, Jiahe [Chinese PLA General Hospital, Department of Nuclear Medicine, Beijing (China)

2011-02-15

Dual-tracer, {sup 18}F-fluorodeoxyglucose and {sup 18}F-fluorodeoxythymidine ({sup 18}F-FDG/{sup 18}F-FLT), dual-modality (positron emission tomography and computed tomography, PET/CT) imaging was used in a clinical trial on differentiation of pulmonary nodules. The aims of this trial were to investigate if multimodality imaging is of advantage and to what extent it could benefit the patients in real clinical settings. Seventy-three subjects in whom it was difficult to establish the diagnosis and determine management of their pulmonary lesions were prospectively enrolled in this clinical trial. All subjects underwent {sup 18}F-FDG and {sup 18}F-FLT PET/CT imaging sequentially. The images were interpreted with different strategies as either individual or combined modalities. The pathological or clinical evidence during a follow-up period of more than 22 months served as the standard of truth. The diagnostic performance of each interpretation and their impact on clinical decision making was investigated. {sup 18}F-FLT/{sup 18}F-FDG PET/CT was proven to be of clinical value in improving the diagnostic confidence in 28 lung tumours, 18 tuberculoses and 27 other benign lesions. The ratio between maximum standardized uptake values of {sup 18}F-FLT and {sup 18}F-FDG was found to be of great potential in separating the three subgroups of patients. The advantage could only be obtained with the full use of the multimodality interpretation. Multimodality imaging induced substantial change in clinical management in 31.5% of the study subjects and partial change in another 12.3%. Multimodality imaging using {sup 18}F-FDG/{sup 18}F-FLT PET/CT provided the best diagnostic efficacy and the opportunity for better management in this group of clinically challenging patients with pulmonary lesions. (orig.)

A methodology for incorporating functional bone marrow sparing in IMRT planning for pelvic radiation therapy

International Nuclear Information System (INIS)

McGuire, Sarah M.; Menda, Yusuf; Boles Ponto, Laura L.; Gross, Brandie; Juweid, Malik; Bayouth, John E.

2011-01-01

Background and purpose: The purpose of this study was to design a radiation therapy treatment planning approach that would spare hematopoietically active bone marrow using [ 18 F]FLT PET imaging. Materials and methods: We have developed an IMRT planning methodology to incorporate functional PET imaging using [ 18 F]FLT scans. Plans were generated for two simulated cervical cancer patients, where pelvic active bone marrow regions were incorporated as avoidance regions based on the ranges: SUV4 ≥ 4; 4 > SUV3 ≥ 3; and 3 > SUV2 ≥ 2. Dose objectives were set to reduce bone marrow volume that received 10 (V 10 ) and 20 (V 20 ) Gy. Results: Active bone marrow regions identified by [ 18 F]FLT with an SUV ≥ 2, SUV ≥ 3, and SUV ≥ 4 represented an average of 43.0%, 15.3%, and 5.8%, respectively of the total osseous pelvis for the two cases studied. Improved dose-volume histograms for all identified bone marrow SUV volumes and decreases in V 10 , and V 20 were achieved without clinically significant changes to PTV or OAR doses. Conclusions: Incorporation of [ 18 F]FLT PET in IMRT planning provides a methodology to reduce radiation dose to active bone marrow without compromising PTV or OAR dose objectives in pelvic malignancies.

Synthesis of novel '4+1' Tc(III)/Re(III) mixed-ligand complexes with dendritically modified ligands

International Nuclear Information System (INIS)

Gniazdowska, E.; Kuenstler, J.U.; Stephan, H.; Pietzsch, H.J.

2006-01-01

Coordination chemistry of technetium and rhenium attracts a considerable interest due to the nuclear medicine applications of their radionuclides. Inert, so-called '3+1' or '4+1' technetium/rhenium mixed-ligand complexes open a new way to application of 99 mTc/ 188 Re labeled compounds in tumor diagnosis and therapy. In the presented paper, authors describe the synthesis and study of novel 99 mTc/ 188 Re complexes with dendritically functionalized tetradentate (tripodal chelator 2,2',2''-nitrilotris(ethanethiol), NS 3 and carboxyl group-bearing ligand, NS 3 (COOH) 3 ) and monodentate (dendritically modified isocyanide, CN-R(COOMe) 3 and isocyanide-modified peptide, CN-GGY) ligands. To verify the identity of the prepared n.c.a. complexes, non-radioactive analogous '4+1' Re compounds were synthesized. The experimental data show that a dendritic modification of the tetradentate/monodentate ligands changes the complex lipophilicity and does not influence its stability

New functionalized β-diketiminate ligands and f elements

International Nuclear Information System (INIS)

Dulong, Florian

2013-01-01

β-diketiminate ligands have received increased interest in coordination chemistry, especially for homogeneous catalysis. Their successful applications arise from an easy and fine tuning of the ligand electronic and geometric properties. However, these modifications are limited to the introduction of neutral donors (ethers or amines), on the nitrogen substituents of the β-diketiminate skeleton. The main focus of this research project is to overcome this limitation by synthesizing new β-diketiminate ligands functionalized by one or two anionic aryl-oxide groups, and to study their coordination chemistry with lanthanide and actinide ions. Access to these species relies on a fine understanding of the mechanism underlying their formation, and the sensitivity of the β-di-iminium skeleton towards nucleophiles (phenols) has been identified as the limiting side reaction in the synthetic route. Addition of reactants in well defined order allowed the formation of two new N-aryl-oxy-β-diketiminate dianions on a multi-gram scale. The two ligands differ by their steric bulk and exhibit different coordination behaviors towards lanthanides and actinide ions, which were rationalized on geometric considerations. The reactivity of three of these new complexes has been investigated. A Ce(III) N-aryl-oxy-β-diketiminate complex exhibits interesting reduction properties, due to the shift of its oxidation potential to negative values by its coordination environment. A Th(IV) complex presents a vacant coordination site, which has been probed with different Lewis bases, emphasizing two spatial arrangements ruled by inter-ligand repulsion. It has been compared to its U(IV) analogue, which can be oxidized to a rare terminal mono-oxo uranium(VI) species. The latter was reversibly reduced to its U(V) and U(IV) derivatives, creating the first series of terminal mono-oxo uranium complexes with three successive oxidation states. These compounds represent an opportunity to better understand

Regulation of Stat5 by FAK and PAK1 in Oncogenic FLT3- and KIT-Driven Leukemogenesis.

Science.gov (United States)

Chatterjee, Anindya; Ghosh, Joydeep; Ramdas, Baskar; Mali, Raghuveer Singh; Martin, Holly; Kobayashi, Michihiro; Vemula, Sasidhar; Canela, Victor H; Waskow, Emily R; Visconte, Valeria; Tiu, Ramon V; Smith, Catherine C; Shah, Neil; Bunting, Kevin D; Boswell, H Scott; Liu, Yan; Chan, Rebecca J; Kapur, Reuben

2014-11-20

Oncogenic mutations of FLT3 and KIT receptors are associated with poor survival in patients with acute myeloid leukemia (AML) and myeloproliferative neoplasms (MPNs), and currently available drugs are largely ineffective. Although Stat5 has been implicated in regulating several myeloid and lymphoid malignancies, how precisely Stat5 regulates leukemogenesis, including its nuclear translocation to induce gene transcription, is poorly understood. In leukemic cells, we show constitutive activation of focal adhesion kinase (FAK) whose inhibition represses leukemogenesis. Downstream of FAK, activation of Rac1 is regulated by RacGEF Tiam1, whose inhibition prolongs the survival of leukemic mice. Inhibition of the Rac1 effector PAK1 prolongs the survival of leukemic mice in part by inhibiting the nuclear translocation of Stat5. These results reveal a leukemic pathway involving FAK/Tiam1/Rac1/PAK1 and demonstrate an essential role for these signaling molecules in regulating the nuclear translocation of Stat5 in leukemogenesis. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Ascorbate regulates haematopoietic stem cell function and leukaemogenesis.

Science.gov (United States)

Agathocleous, Michalis; Meacham, Corbin E; Burgess, Rebecca J; Piskounova, Elena; Zhao, Zhiyu; Crane, Genevieve M; Cowin, Brianna L; Bruner, Emily; Murphy, Malea M; Chen, Weina; Spangrude, Gerald J; Hu, Zeping; DeBerardinis, Ralph J; Morrison, Sean J

2017-09-28

Stem-cell fate can be influenced by metabolite levels in culture, but it is not known whether physiological variations in metabolite levels in normal tissues regulate stem-cell function in vivo. Here we describe a metabolomics method for the analysis of rare cell populations isolated directly from tissues and use it to compare mouse haematopoietic stem cells (HSCs) to restricted haematopoietic progenitors. Each haematopoietic cell type had a distinct metabolic signature. Human and mouse HSCs had unusually high levels of ascorbate, which decreased with differentiation. Systemic ascorbate depletion in mice increased HSC frequency and function, in part by reducing the function of Tet2, a dioxygenase tumour suppressor. Ascorbate depletion cooperated with Flt3 internal tandem duplication (Flt3 ITD ) leukaemic mutations to accelerate leukaemogenesis, through cell-autonomous and possibly non-cell-autonomous mechanisms, in a manner that was reversed by dietary ascorbate. Ascorbate acted cell-autonomously to negatively regulate HSC function and myelopoiesis through Tet2-dependent and Tet2-independent mechanisms. Ascorbate therefore accumulates within HSCs to promote Tet activity in vivo, limiting HSC frequency and suppressing leukaemogenesis.

F-18 FLT PET : A Noninvasive Diagnostic Tool for Visualization of the Bone Marrow Compartment in Patients With Aplastic Anemia A Pilot Study

NARCIS (Netherlands)

Agool, Ali; Slart, Riemer H. J. A.; Kluin, Philip M.; de Wolf, Joost Th. M.; Dierckx, Rudi A. J. O.; Vellenga, Edo

Rationale: A discordant relationship between bone marrow cellularity and peripheral blood findings is regularly noticed in patients with aplastic anemia (AA). Therefore, the feasibility of 3-F-18 fluoro-3-deoxy-L-thymidine (F-18 FLT PET was tested as a noninvasive tool to visualize the total

submitter Emerging importance of chemokine receptor CXCR3 and its ligands in cardiovascular diseases

CERN Document Server

Altara, R; Brandao, R D; Zeidan, A; Booz, G W; Zouein, F A

2016-01-01

The CXC chemokines, CXCL4, -9, -10, -11, CXCL4L1, and the CC chemokine CCL21, activate CXC chemokine receptor 3 (CXCR3), a cell-surface G protein-coupled receptor expressed mainly by Th1 cells, cytotoxic T (Tc) cells and NK cells that have a key role in immunity and inflammation. However, CXCR3 is also expressed by vascular smooth muscle and endothelial cells, and appears to be important in controlling physiological vascular function. In the last decade, evidence from pre-clinical and clinical studies has revealed the participation of CXCR3 and its ligands in multiple cardiovascular diseases (CVDs) of different aetiologies including atherosclerosis, hypertension, cardiac hypertrophy and heart failure, as well as in heart transplant rejection and transplant coronary artery disease (CAD). CXCR3 ligands have also proven to be valid biomarkers for the development of heart failure and left ventricular dysfunction, suggesting an underlining pathophysiological relation between levels of these chemokines and the deve...

Spaceflight effects on T lymphocyte distribution, function and gene expression

Science.gov (United States)

Gridley, Daila S.; Slater, James M.; Luo-Owen, Xian; Rizvi, Asma; Chapes, Stephen K.; Stodieck, Louis S.; Ferguson, Virginia L.; Pecaut, Michael J.

2009-01-01

The immune system is highly sensitive to stressors present during spaceflight. The major emphasis of this study was on the T lymphocytes in C57BL/6NTac mice after return from a 13-day space shuttle mission (STS-118). Spleens and thymuses from flight animals (FLT) and ground controls similarly housed in animal enclosure modules (AEM) were evaluated within 3–6 h after landing. Phytohemagglutinin-induced splenocyte DNA synthesis was significantly reduced in FLT mice when based on both counts per minute and stimulation indexes (P < 0.05). Flow cytometry showed that CD3+ T and CD19+ B cell counts were low in spleens from the FLT group, whereas the number of NK1.1+ natural killer (NK) cells was increased (P < 0.01 for all three populations vs. AEM). The numerical changes resulted in a low percentage of T cells and high percentage of NK cells in FLT animals (P < 0.05). After activation of spleen cells with anti-CD3 monoclonal antibody, interleukin-2 (IL-2) was decreased, but IL-10, interferon-γ, and macrophage inflammatory protein-1α were increased in FLT mice (P < 0.05). Analysis of cancer-related genes in the thymus showed that the expression of 30 of 84 genes was significantly affected by flight (P < 0.05). Genes that differed from AEM controls by at least 1.5-fold were Birc5, Figf, Grb2, and Tert (upregulated) and Fos, Ifnb1, Itgb3, Mmp9, Myc, Pdgfb, S100a4, Thbs, and Tnf (downregulated). Collectively, the data show that T cell distribution, function, and gene expression are significantly modified shortly after return from the spaceflight environment. PMID:18988762

Angiogenesis-Related Biomarkers (sFlt-1/PLGF in the Prediction and Diagnosis of Placental Dysfunction: An Approach for Clinical Integration

Directory of Open Access Journals (Sweden)

Ignacio Herraiz

2015-08-01

Full Text Available Placental dysfunction is involved in a group of obstetrical conditions including preeclampsia, intrauterine growth restriction, and placental abruption. Their timely and accurate recognition is often a challenge since diagnostic criteria are still based on nonspecific signs and symptoms. The discovering of the role of angiogenic-related factors (sFlt-1/PlGF in the underlying pathophysiology of placental dysfunction, taking into account that angiogenesis-related biomarkers are not specific to any particular placental insufficiency-related disease, has marked an important step for improving their early diagnosis and prognosis assessment. However, sFlt-1/PlGF has not been yet established as a part of most guidelines. We will review the current evidence on the clinical utility of sFlt-1/PlGF and propose a new protocol for its clinical integration.

Altered hemodynamics and hyperuricemia accompany an elevated sFlt-1/PlGF ratio before the onset of early severe preeclampsia.

LENUS (Irish Health Repository)

Doherty, Anne

2014-08-01

Early identification of women at risk of developing early-onset severe preeclampsia (sPE) is a key objective in obstetrics. An elevated ratio of serum soluble fms-like tyrosine kinase (sFlt-1) to placenta-like growth factor (PlGF) (sFlt-1\\/PlGF ratio) precedes overt hypertension. The longitudinal relationship between this biomarker, maternal hemodynamics, and maternal serum uric acid during the pre-clinical phase is unknown.

Investigation of the pharmacokinetics of 3'-deoxy-3'-[18F]fluorothymidine uptake in the bone marrow before and early after initiation of chemoradiation therapy in head and neck cancer

International Nuclear Information System (INIS)

Menda, Yusuf; Boles Ponto, Laura L.; Dornfeld, Kenneth J.; Tewson, Timothy J.; Watkins, G. Leonard; Gupta, Anjali K.; Anderson, Carryn; McGuire, Sarah; Schultz, Michael K.; Sunderland, John J.; Graham, Michael M.; Buatti, John M.

2010-01-01

Introduction: The kinetics of the bone marrow uptake of 3'-deoxy-3'-[ 18 F]fluorothymidine (FLT) before and early after initiation of chemoradiation therapy was investigated in patients with head and neck cancer. Methods: Fourteen subjects with head and neck cancer underwent FLT positron emission tomography (PET) at baseline and after 10 Gy of radiation therapy. Thirteen subjects also received one cycle of platinum-based chemotherapy before the second FLT PET. Kinetic parameters, including the flux constant based on compartmental analysis (K FLT ) and the Patlak constant (K Patlak ) for cervical marrow, were calculated. Standardized uptake values (SUVs) for the cervical marrow (inside the radiation field) and lumbar spine marrow (outside the radiation field) were also determined. Results: There was a significant drop in FLT uptake in the bone marrow inside the radiation field. Mean pretreatment uptake values for the cervical spine were SUV=3.08±0.66, K FLT =0.045±0.016 min -1 and K Patlak =0.039±0.013 min -1 . After treatment, these values were SUV=0.74±0.19, K FLT =0.011±0.005 min -1 and K Patlak =0.005±0.002 min -1 . Compartmental analysis revealed a significant drop in k 3 in irradiated cervical marrow. FLT uptake in the bone marrow outside the radiation field exhibited a significantly smaller decrease. Conclusions: There is a marked decrease in FLT uptake in irradiated bone marrow after 10 Gy of radiation therapy to the head and neck. The drop in FLT uptake in irradiated marrow is due to a significant decrease in the net phosphorylation rate of FLT.

The Evaluation of Novel Camphor-derived Pyridyl Ligands as ...

African Journals Online (AJOL)

NJD

2009-03-03

Mar 3, 2009 ... The structures of the copper (II) complexes of the ligands were calculated using ONIOM density functional theory and the results suggest that chiral induction to the alkene functional group is indeed lacking. This explains the moderate experimental selectivities obtained. KEYWORDS. Camphor ligands ...

Role of ligand-ligand vs. core-core interactions in gold nanoclusters.

Science.gov (United States)

Milowska, Karolina Z; Stolarczyk, Jacek K

2016-05-14

The controlled assembly of ligand-coated gold nanoclusters (NCs) into larger structures paves the way for new applications ranging from electronics to nanomedicine. Here, we demonstrate through rigorous density functional theory (DFT) calculations employing novel functionals accounting for van der Waals forces that the ligand-ligand interactions determine whether stable assemblies can be formed. The study of NCs with different core sizes, symmetry forms, ligand lengths, mutual crystal orientations, and in the presence of a solvent suggests that core-to-core van der Waals interactions play a lesser role in the assembly. The dominant interactions originate from combination of steric effects, augmented by ligand bundling on NC facets, and related to them changes in electronic properties induced by neighbouring NCs. We also show that, in contrast to standard colloidal theory approach, DFT correctly reproduces the surprising experimental trends in the strength of the inter-particle interaction observed when varying the length of the ligands. The results underpin the importance of understanding NC interactions in designing gold NCs for a specific function.

Synthesis of an S T = 7 [Mn 3 ] Mixed-Valence Complex Based on 1,3-Propanediol Ligand Derivatives and Its One-Dimensional Assemblies

KAUST Repository

Huang, Jian; Wu, Gang; Bai, Jiaquan; Jiang, Yuan; Li, Guanghua; Qiu, Shilun; Clé rac, Rodolphe

2013-01-01

. In this work, a new ST = 7 trinuclear mixed-valence Mn complex, [MnIIIMnII 2(LA) 2(Br)4(CH3OH)6] ·Br· (CH3OH)1.5·(H2O)0.5 (1), is reported using a pyridinium-functionalized 1,3-propanediol ligand (H 2LABr = 1-(3-bromo-2,2-bis

Synthesis and Characterization of a Ru(II Complex with Functionalized Phenanthroline Ligands Having Single-Double Linked Anthracenyl and 1-Methoxy-1-buten-3-yne Moieties

Directory of Open Access Journals (Sweden)

Adewale O. Adeloye

2010-10-01

Full Text Available Two series of bidentate polypyridine ligands, made of phenanthroline chelating subunits having substituted mono-and di-anthracenyl groups, and 1-methoxy-1-buten-3-yne at the 4 and 7-positions with the corresponding heteroleptic Ru(II complex have been synthesized and characterized. The complex is formulated as [(Ru(L1(L2(NCS2], (where L1 = 4-(9-dianthracenyl-10-(2,3-dimethylacrylic acid-7-(9-anthracenyl-10-(2,3-dimethylacrylic acid-1,10-phenanthroline and L2 = 4,7-bis(1-methoxy-1-buten-3-yne-1,10-phenanthroline. The Ru(II complex shows characteristic broad and intense metal-to-ligand charge transfer (MLCT bands absorption and appreciable photoluminescence spanning the visible region. The ligands and complex were characterized by FT-IR, 1H, 13C NMR spectroscopy, UV-Vis, photoluminescence and elemental analysis (see in supplementary materials. The anchoring groups in both ligands have allowed an extended delocalization of acceptor orbital of the metal-to-ligand charge-transfer (MLCT excited state.

Evaluation of 18F-FDG and 18F-FLT for monitoring therapeutic responses of colorectal cancer cells to radiotherapy

International Nuclear Information System (INIS)

Wang, Hui; Liu, Bo; Tian, Jiahe; Xu, Baixuan; Zhang, Jinming; Qu, Baolin; Chen, Yingmao

2013-01-01

In order to compare the efficacy of 18 F-fluorothymidine (FLT) and 18 F-fluorodeoxyglucose (FDG) for monitoring early responses to irradiation, two human colorectal cancer (CRC) cell lines SW480 and SW620, which were derived from the primary lesions and the metastatic lymph node, underwent X-ray irradiation of 0, 10, or 20 Gy and were examined at 0, 24 and 72 h After irradiation, reduced proliferation of both SW480 and SW620 cells was observed in a dose-dependent manner (P < 0.001), G0-G1 arrest was also noted in both cell types after 72 h in the 20 Gy group (P < 0.001). Although increased apoptosis was observed in both cell lines after irradiation (P < 0.001), a greater percentage of SW480 cells underwent apoptosis in response to irradiation than SW620 cells. Increased Hsp27 and decreased integrin β 3 , Ki67 and VEGFR2 expression was observed over time via immunocytochemistry and Western blot analysis (P < 0.001), however, no significant changes were noted in response to irradiation. Finally, reduced uptake of 18 F-FLT by SW480 or SW620 cells was observed at 24-h post-irradiation, however, reduced 18 F-FDG uptake was only observed after 72 h. Therefore, we conclude that 18 F-FLT is a more suitable positron emission tomography (PET) tracer for monitoring early responses to irradiation in primary and metastatic lymph node CRC cells

Budget impact analysis of sFlt-1/PlGF ratio as prediction test in Italian women with suspected preeclampsia.

Science.gov (United States)

Frusca, Tiziana; Gervasi, Maria-Teresa; Paolini, Davide; Dionisi, Matteo; Ferre, Francesca; Cetin, Irene

2017-09-01

Preeclampsia (PE) is a pregnancy disease which represents a leading cause of maternal and perinatal mortality and morbidity. Accurate prediction of PE risk could provide an increase in health benefits and better patient management. To estimate the economic impact of introducing Elecsys sFlt-1/PlGF ratio test, in addition to standard practice, for the prediction of PE in women with suspected PE in the Italian National Health Service (INHS). A decision tree model has been developed to simulate the progression of a cohort of pregnant women from the first presentation of clinical suspicion of PE in the second and third trimesters until delivery. The model provides an estimation of the financial impact of introducing sFlt-1/PlGF versus standard practice. Clinical inputs have been derived from PROGNOSIS study and from literature review, and validated by National Clinical Experts. Resources and unit costs have been obtained from Italian-specific sources. Healthcare costs associated with the management of a pregnant woman with clinical suspicion of PE equal €2384 when following standard practice versus €1714 using sFlt-1/PlGF ratio test. Introduction of sFlt-1/PlGF into hospital practice is cost-saving. Savings are generated primarily through improvement in diagnostic accuracy and reduction in unnecessary hospitalization for women before PE's onset.

Do orphan G-protein-coupled receptors have ligand-independent functions? New insights from receptor heterodimers

OpenAIRE

Levoye, Angélique; Dam, Julie; Ayoub, Mohammed A; Guillaume, Jean-Luc; Jockers, Ralf

2006-01-01

G-protein-coupled receptors (GPCRs) are important drug targets and are involved in virtually every biological process. However, there are still more than 140 orphan GPCRs, and deciphering their function remains a priority for fundamental and clinical research. Research on orphan GPCRs has concentrated mainly on the identification of their natural ligands, whereas recent data suggest additional ligand-independent functions for these receptors. This emerging concept is connected with the observ...

Synthesis of an S T = 7 [Mn 3 ] Mixed-Valence Complex Based on 1,3-Propanediol Ligand Derivatives and Its One-Dimensional Assemblies

KAUST Repository

Huang, Jian

2013-10-07

Controlled organization of high-spin complexes and single-molecule magnets is a great challenge in molecular magnetism in order to study the effect of the intercomplex magnetic interactions on the intrinsic properties of a given magnetic object. In this work, a new ST = 7 trinuclear mixed-valence Mn complex, [MnIIIMnII 2(LA) 2(Br)4(CH3OH)6] ·Br· (CH3OH)1.5·(H2O)0.5 (1), is reported using a pyridinium-functionalized 1,3-propanediol ligand (H 2LABr = 1-(3-bromo-2,2-bis(hydroxymethyl)propyl)pyridinium bromide). Using azido anions as bridging ligands and different pyridinium-functionalized 1,3-propanediol ligands (H2LBBr = 1-(3-bromo-2,2-bis(hydroxymethyl)propyl)-4-picolinium bromide; H 2LCBr = 1-(3-bromo-2,2-bis(hydroxymethyl)propyl)-3,5- lutidinium bromide), the linear [MnIIIMnII 2L2X4]+ building block has been assembled into one-dimensional coordination networks: [MnIIIMn II 2(LA)2(Br)4(CH 3OH)4(N3)]·((C2H 5)2O)1.25 (2∞), [MnIIIMn II 2(LB)2(Br)4(C 2H5OH)(CH3OH)(H2O) 2(N3)]·(H2O)0.25 (3∞), and [MnIIIMnII 2(LC) 2(Cl)3.8(Br)0.2(C2H 5OH)3(CH3OH)(N3)] (4∞). The syntheses, characterization, crystal structures, and magnetic properties of these new [Mn3]-based materials are reported. © 2013 American Chemical Society.

Histamine H3 receptor ligands in the group of (homo)piperazine derivatives.

Science.gov (United States)

Szczepanska, Katarzyna; Kuder, Kamil; Kiec-Kononowicz, Katarzyna

2017-11-23

Since its' discovery in 1983, followed by gene cloning in 1999, the histamine H3 receptor served as an outstanding target for drug discovery. The wide spectrum of possible therapeutic implications make H3R's one of the most researched areas in the vast GPCR ligands field - started from imidazole containing ligands, through various successful imidazole replacements, with recent introduction of Wakix® to pharmaceutical market. One of such replacements is piperazine moiety, a significant versatile scaffold in rational drug design for most of the GPCR ligands. Therefore, herein we review ligands built on piperazine, as well as its seven membered analogue azepine, that target H3R's and their potential therapeutical applications, in order to elucidate the current state of the art in this vast field. Due to a high level of structural divergence among compounds described herein, we decided to divide them into groups, where the key division element was the position of nitrogen basicity decreasing moieties in (homo)piperazine ring. Paying attention to a number of published structures and their overall high biological activity, one can realize that the (homo)piperazine scaffold bids a versatile template also for histamine H3 receptor ligands. With two possible substitution sites and therefore a number of possible structural combinations, piperazine derivatives stand as one of the largest group of high importance among H3R ligands. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Ligands in PSI structures

International Nuclear Information System (INIS)

Kumar, Abhinav; Chiu, Hsiu-Ju; Axelrod, Herbert L.; Morse, Andrew; Elsliger, Marc-André; Wilson, Ian A.; Deacon, Ashley

2010-01-01

A survey of the types and frequency of ligands that are bound to PSI structures is analyzed as well as their utility in functional annotation of previously uncharacterized proteins. Approximately 65% of PSI structures report some type of ligand(s) that is bound in the crystal structure. Here, a description is given of how such ligands are handled and analyzed at the JCSG and a survey of the types, variety and frequency of ligands that are observed in the PSI structures is also compiled and analyzed, including illustrations of how these bound ligands have provided functional clues for annotation of proteins with little or no previous experimental characterization. Furthermore, a web server was developed as a tool to mine and analyze the PSI structures for bound ligands and other identifying features

Ligand Electron Density Shape Recognition Using 3D Zernike Descriptors

Science.gov (United States)

Gunasekaran, Prasad; Grandison, Scott; Cowtan, Kevin; Mak, Lora; Lawson, David M.; Morris, Richard J.

We present a novel approach to crystallographic ligand density interpretation based on Zernike shape descriptors. Electron density for a bound ligand is expanded in an orthogonal polynomial series (3D Zernike polynomials) and the coefficients from this expansion are employed to construct rotation-invariant descriptors. These descriptors can be compared highly efficiently against large databases of descriptors computed from other molecules. In this manuscript we describe this process and show initial results from an electron density interpretation study on a dataset containing over a hundred OMIT maps. We could identify the correct ligand as the first hit in about 30 % of the cases, within the top five in a further 30 % of the cases, and giving rise to an 80 % probability of getting the correct ligand within the top ten matches. In all but a few examples, the top hit was highly similar to the correct ligand in both shape and chemistry. Further extensions and intrinsic limitations of the method are discussed.

MO-AB-BRA-06: Dynamic FLT PET for Investigating Potential Synergistic Therapeutic Targets During Anti-Angiogenic Treatment

Energy Technology Data Exchange (ETDEWEB)

Scarpelli, M; Perlman, S; Liu, G [University of Wisconsin-Madison, Madison, WI (United States); Simoncic, U [Jozef Stefan Institute, Ljubljana (Slovenia); Jeraj, R [University of Wisconsin-Madison, Madison, WI (United States); Jozef Stefan Institute, Ljubljana (Slovenia)

2016-06-15

Purpose: Novel treatment strategies for metastatic cancer patients involve synergistically combining treatments with the hope of improving outcomes. This study investigated changes in tumor proliferative and vascular characteristics derived from dynamic [F-18]FLT PET during antiangiogenic treatment with the goal of identifying synergistic treatment opportunities. Methods: Patients with various solid cancers underwent continuous three-week cycles of anti-angiogenic treatment with intermittent dosing (two-weeks-on/one-week-off). Patients received up to six dynamic FLT PET/CT scans (days 0, 14, and 21 of cycle 1 (C1) and cycle 3 (C3)). Tumor proliferative (Kflt, net uptake rate) and vascular parameters (K1 blood-to-tissue transfer; Vb, vascular fraction) were calculated using a two-tissue compartment four-rate parameter kinetic model. Relative changes in these parameters, from day 0 to 14 (TxResp) and day 14 to 21 (offTxResp), were calculated. Significant differences were tested using Wilcoxon signed-rank test and significant correlations were tested using Spearman correlation. Results: Thirty patients were evaluable for C1 offTxResp with median values for Kflt, K1, and Vb of +30%, +35% and +30%, respectively. The fractions of patients with positive C1 offTxResp were: 21/30 for Ki, 24/30 for K1, 21/30 for Vb, and 12/30 had positive offTxResp for all three kinetic parameters. The offTxResp in C3 was not significantly different from C1 for any of the kinetic parameters. Significant correlations were found between TxResp and offTxResp in C1 for Kflt (ρ=-0.52, p=0.014), K1 (ρ=−0.61, p=0.003) and Vb (ρ=−0.80, p<0.001). Similar correlations were found for Kflt (ρ=-1, p=0.017) and K1 (ρ=−1, p=0.017) for the five patients evaluable in C3. Conclusion: Dynamic FLT PET showed evidence of distinct vascular and proliferative increases during off treatment weeks that could potentially be targeted with synergistic therapy. Early changes in kinetic parameters were

Activation of PAR-1/NADPH Oxidase/ROS Signaling Pathways is Crucial for the Thrombin-Induced sFlt-1 Production in Extravillous Trophoblasts: Possible Involvement in the Pathogenesis of Preeclampsia

Directory of Open Access Journals (Sweden)

Qi-tao Huang

2015-03-01

Full Text Available Backgrounds/Aims: Preeclampsia was characterized by excessive thrombin generation in placentas and previous researches showed that thrombin could enhance soluble Fms-like tyrosine kinase 1 (sFlt-1 expression in first trimester trophoblasts. However, the detailed mechanism for the sFlt-1 over-production induced by thrombin was largely unknown. The purpose of this study was to explore the possible signaling pathway of thrombin-induced sFlt-1 production in extravillous trophoblasts (EVT. Methods: An EVT cell line (HRT-8/SVneo was treated with various concentrations of thrombin. The mRNA expression and protein secretion of sFlt-1 in EVT were detected with real-time polymerase chain reaction and ELISA, respectively. The levels of intracellular reactive oxygen species (ROS production were determined by DCFH-DA. Results: Exposure of EVT to thrombin induced increased intracellular ROS generation and overexpression of sFlt-1 at both mRNA and protein levels in a dose dependent manner. Short interfering RNA (siRNA directed against PAR-1 or apocynin (an inhibitor of NADPH oxidase could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels. Conclusions: Our results suggested that thrombin increased sFlt-1 production in EVT via the PAR-1 /NADPH oxidase /ROS signaling pathway. This also highlights the PAR-1 / NADPH oxidase / ROS pathway might be a potential therapeutic target for the prevention of preeclampsia in the future.

Activation of PAR-1/NADPH oxidase/ROS signaling pathways is crucial for the thrombin-induced sFlt-1 production in extravillous trophoblasts: possible involvement in the pathogenesis of preeclampsia.

Science.gov (United States)

Huang, Qi-Tao; Chen, Jian-Hong; Hang, Li-Lin; Liu, Shi-San; Zhong, Mei

2015-01-01

Preeclampsia was characterized by excessive thrombin generation in placentas and previous researches showed that thrombin could enhance soluble Fms-like tyrosine kinase 1 (sFlt-1) expression in first trimester trophoblasts. However, the detailed mechanism for the sFlt-1 over-production induced by thrombin was largely unknown. The purpose of this study was to explore the possible signaling pathway of thrombin-induced sFlt-1 production in extravillous trophoblasts (EVT). An EVT cell line (HRT-8/SVneo) was treated with various concentrations of thrombin. The mRNA expression and protein secretion of sFlt-1 in EVT were detected with real-time polymerase chain reaction and ELISA, respectively. The levels of intracellular reactive oxygen species (ROS) production were determined by DCFH-DA. Exposure of EVT to thrombin induced increased intracellular ROS generation and overexpression of sFlt-1 at both mRNA and protein levels in a dose dependent manner. Short interfering RNA (siRNA) directed against PAR-1 or apocynin (an inhibitor of NADPH oxidase) could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels. Our results suggested that thrombin increased sFlt-1 production in EVT via the PAR-1 /NADPH oxidase /ROS signaling pathway. This also highlights the PAR-1 / NADPH oxidase / ROS pathway might be a potential therapeutic target for the prevention of preeclampsia in the future. © 2015 S. Karger AG, Basel.

Functional anthology of intrinsic disorder. 3. Ligands, post-translational modifications, and diseases associated with intrinsically disordered proteins.

Science.gov (United States)

Xie, Hongbo; Vucetic, Slobodan; Iakoucheva, Lilia M; Oldfield, Christopher J; Dunker, A Keith; Obradovic, Zoran; Uversky, Vladimir N

2007-05-01

devoted to the presentation of 87 Swiss-Prot keywords attributed to the cellular components, domains, technical terms, developmental processes, and coding sequence diversities possessing strong positive and negative correlation with long disordered regions (Vucetic, S.; Xie, H.; Iakoucheva, L. M.; Oldfield, C. J.; Dunker, A. K.; Obradovic, Z.; Uversky, V. N. Functional anthology of intrinsic disorder. 2. Cellular components, domains, technical terms, developmental processes, and coding sequence diversities correlated with long disordered regions. J. Proteome Res. 2007, 5, 1899-1916). Protein structure and functionality can be modulated by various post-translational modifications or/and as a result of binding of specific ligands. Numerous human diseases are associated with protein misfolding/misassembly/misfunctioning. This work concludes the series of papers dedicated to the functional anthology of intrinsic disorder and describes approximately 80 Swiss-Prot functional keywords that are related to ligands, post-translational modifications, and diseases possessing strong positive or negative correlation with the predicted long disordered regions in proteins.

Ligand-receptor Interactions by NMR Spectroscopy

Directory of Open Access Journals (Sweden)

Novak. P.

2008-04-01

Full Text Available Today NMR spectroscopy is a method of choice for elucidation of interactions between biomolecules and the potential ligands. Knowledge on these interactions is an essential prerequisite for the rational drug design. The most important contribution of NMR to drug design a few years ago was the 3D structure determination of proteins. Besides delivering the 3D structures of the free proteins as a raw material for the modeling studies on ligand binding, NMR can directly yield valuable experimental data on the biologically important protein-ligand complexes. In addition to X-ray diffraction, NMR spectroscopy can provide information on the internal protein dynamics ordynamics of intermolecular interactions. Changes in NMR parameters allow us to detect ("SAR by NMR" and quantitatively determine binding affinities (titration, diffusion NMR experiments, etc. of potential ligands. Also, it is possible to determine the binding site and conformations of ligands, receptors and receptor-ligand complexes with the help of NMR methods such as tr-NOESY. Epitopes or functional groups responsible for binding of ligands to the receptor can be identified by employing STD or WaterLOGSY experiments. In this review are described some of the most frequent NMR methods for the characterization of the interactions between biomolecules and ligands, together with their advantages and disadvantages.

Intuitive Density Functional Theory-Based Energy Decomposition Analysis for Protein-Ligand Interactions.

Science.gov (United States)

Phipps, M J S; Fox, T; Tautermann, C S; Skylaris, C-K

2017-04-11

First-principles quantum mechanical calculations with methods such as density functional theory (DFT) allow the accurate calculation of interaction energies between molecules. These interaction energies can be dissected into chemically relevant components such as electrostatics, polarization, and charge transfer using energy decomposition analysis (EDA) approaches. Typically EDA has been used to study interactions between small molecules; however, it has great potential to be applied to large biomolecular assemblies such as protein-protein and protein-ligand interactions. We present an application of EDA calculations to the study of ligands that bind to the thrombin protein, using the ONETEP program for linear-scaling DFT calculations. Our approach goes beyond simply providing the components of the interaction energy; we are also able to provide visual representations of the changes in density that happen as a result of polarization and charge transfer, thus pinpointing the functional groups between the ligand and protein that participate in each kind of interaction. We also demonstrate with this approach that we can focus on studying parts (fragments) of ligands. The method is relatively insensitive to the protocol that is used to prepare the structures, and the results obtained are therefore robust. This is an application to a real protein drug target of a whole new capability where accurate DFT calculations can produce both energetic and visual descriptors of interactions. These descriptors can be used to provide insights for tailoring interactions, as needed for example in drug design.

Investigation of Uranyl Nitrate Ion Pairs Complexed with Amide Ligands using Electrospray Ionization Ion Trap Mass Spectrometry and Density Functional Theory

International Nuclear Information System (INIS)

Groenewold, Gary S.; Dinescu, Adriana; Benson, Michael T.; Gresham, Garold L.; van Stipdonk, Michael J.

2011-01-01

Ion populations formed from electrospray of uranyl nitrate solutions containing different amides vary depending on ligand nucleophilicity and steric crowding at the metal center. The most abundant species were ion pair complexes having the general formula (UO2(NO3)(amide)n=2,3)+, and complexes containing the amide conjugate base, reduced uranyl UO2+, and a 2+ charge were also formed. The formamide experiment produced the greatest diversity of species that stems from weaker amide binding leading to dissociation and subsequent solvent coordination or metal reduction. Experiments using methyl formamide, dimethyl formamide, acetamide, and methyl acetamide produced ion pair and doubly charged complexes that were more abundant, and less abundant complexes containing solvent or reduced uranyl. This pattern is reversed in the dimethylacetamide experiment, which displayed reduced doubly charged complexes and augmented reduced uranyl complexes. DFT investigations of the tris-amide ion pair complexes showed that inter-ligand repulsion distorts the amide ligands out of the uranyl equatorial plane, and that complex stabilities do not increase with increasing amide nucleophilicity. Elimination of an amide ligand largely relieves the interligand repulsion, and the remaining amide ligands become closely aligned with the equatorial plane in the structures of the bis-amide ligands. The studies show that the phenomenological distribution of coordination complexes in a metal-ligand electrospray experiment is a function of both ligand nucleophilicity and interligand repulsion, and that the latter factor begins exerting influence even in the case of relatively small ligands like the substituted methyl-formamide and methyl-acetamide ligands.

Improving binding mode and binding affinity predictions of docking by ligand-based search of protein conformations: evaluation in D3R grand challenge 2015

Science.gov (United States)

Xu, Xianjin; Yan, Chengfei; Zou, Xiaoqin

2017-08-01

The growing number of protein-ligand complex structures, particularly the structures of proteins co-bound with different ligands, in the Protein Data Bank helps us tackle two major challenges in molecular docking studies: the protein flexibility and the scoring function. Here, we introduced a systematic strategy by using the information embedded in the known protein-ligand complex structures to improve both binding mode and binding affinity predictions. Specifically, a ligand similarity calculation method was employed to search a receptor structure with a bound ligand sharing high similarity with the query ligand for the docking use. The strategy was applied to the two datasets (HSP90 and MAP4K4) in recent D3R Grand Challenge 2015. In addition, for the HSP90 dataset, a system-specific scoring function (ITScore2_hsp90) was generated by recalibrating our statistical potential-based scoring function (ITScore2) using the known protein-ligand complex structures and the statistical mechanics-based iterative method. For the HSP90 dataset, better performances were achieved for both binding mode and binding affinity predictions comparing with the original ITScore2 and with ensemble docking. For the MAP4K4 dataset, although there were only eight known protein-ligand complex structures, our docking strategy achieved a comparable performance with ensemble docking. Our method for receptor conformational selection and iterative method for the development of system-specific statistical potential-based scoring functions can be easily applied to other protein targets that have a number of protein-ligand complex structures available to improve predictions on binding.

The concept of mixed organic ligands in metal-organic frameworks: design, tuning and functions.

Science.gov (United States)

Yin, Zheng; Zhou, Yan-Ling; Zeng, Ming-Hua; Kurmoo, Mohamedally

2015-03-28

The research on metal-organic frameworks (MOFs) has been developing at an extraordinary pace in its two decades of existence, as judged by the exponential growth of novel structures and the constant expansion of its applicability and research scope. A major part of the research and its success are due to the vital role of the concept of mixed organic ligands in the design, tuning and functions. This perspective, therefore, reviews the recent advances in MOFs based on this concept, which is generally based on employing a small polydentate ligand (here labelled as "nodal ligand") to form either clusters, rods or layers, which are then connected by a second ditopic linker ligand to form the framework. The structures of the materials can be grouped into the following three categories: layer-spacer (usually known as pillared-layer), rod-spacer, and cluster-spacer based MOFs. Depending on the size and geometry of the spacer ligands, interpenetrations of frameworks are occasionally found. These MOFs show a wide range of properties such as (a) crystal-to-crystal transformations upon solvent modifications, post-synthetic metal exchange or ligand reactions, (b) gas sorption, solvent selectivity and purification, (c) specific catalysis, (d) optical properties including colour change, luminescence, non-linear optic, (e) short- and long range magnetic ordering, metamagnetism and reversible ground-state modifications and (f) drug and iodine carriers with controlled release. In the following, we will highlight the importance of the above concept in the design, tuning, and functions of a selection of existing MOFs having mixed organic ligands and their associated structures and properties. The results obtained so far using this concept look very promising for fine-tuning the pore size and shape for selective adsorption and specificity in catalytic reactions, which appears to be one way to propel the advances in the application and commercialization of MOFs.

Mapping Radiation Injury and Recovery in Bone Marrow Using 18F-FLT PET/CT and USPIO MRI in a Rat Model.

Science.gov (United States)

Rendon, David A; Kotedia, Khushali; Afshar, Solmaz F; Punia, Jyotinder N; Sabek, Omaima M; Shirkey, Beverly A; Zawaski, Janice A; Gaber, M Waleed

2016-02-01

We present and test the use of multimodality imaging as a topological tool to map the amount of the body exposed to ionizing radiation and the location of exposure, which are important indicators of survival and recovery. To achieve our goal, PET/CT imaging with 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) was used to measure cellular proliferation in bone marrow (BM), whereas MRI using ultra-small superparamagnetic iron oxide (USPIO) particles provided noninvasive information on radiation-induced vascular damage. Animals were x-ray-irradiated at a dose of 7.5 Gy with 1 of 3 radiation schemes-whole-body irradiation, half-body shielding (HBS), or 1-leg shielding (1LS)-and imaged repeatedly. The spatial information from the CT scan was used to segment the region corresponding to BM from the PET scan using algorithms developed in-house, allowing for quantification of proliferating cells, and BM blood volume was estimated by measuring the changes in the T2 relaxation rates (ΔR2) collected from MR scans. (18)F-FLT PET/CT imaging differentiated irradiated from unirradiated BM regions. Two days after irradiation, proliferation of 1LS animals was significantly lower than sham (P = 0.0001, femurs; P < 0.0001, tibias) and returned to sham levels by day 10 (P = 0.6344, femurs; P = 0.3962, tibias). The degree of shielding affected proliferation recovery, showing an increase in the irradiated BM of the femurs, but not the tibias, of HBS animals when compared with 1LS (P = 0.0310, femurs; P = 0.5832, tibias). MRI of irradiated spines detected radiation-induced BM vascular damage, measured by the significant increase in ΔR2 2 d after whole-body irradiation (P = 0.0022) and HBS (P = 0.0003) with a decreasing trend of values, returning to levels close to baseline over 10 d. Our data were corroborated using γ-counting and histopathology. We demonstrated that (18)F-FLT PET/CT and USPIO MRI are valuable tools in mapping regional radiation exposure and the effects of radiation on

In vitro modulation of radiation-induced FAS-related apoptosis in CD34+ progenitor cells by combination cytokines

International Nuclear Information System (INIS)

Drouet, M.; Mathieu, J.; Grenier, N.; Soutif, A.; Herodin, F.

1998-01-01

Combination cytokines such as SCF, Flt-3 ligand, IL-3 and thrombopoietin can modulate Fas mRNA expression by in vitro irradiated CD34 + cells which results in a moderate decrease of apoptotic ratio and an improved rate of clonogenicity of the irradiated progenitors. (authors)

Serotoninergic receptors in brain tissue: properties and identification of various 3H-ligand binding sites in vitro

International Nuclear Information System (INIS)

Leysen, J.E.

1981-01-01

In vitro binding studies to serotoninergic receptors were performed using 3 H-LSD, 3 H-5-HT and 3 H-spiperone. An overwiew is given on findings using these three ligands with respect to the following: localization of specific binding sites, in various animal species, the regional distribution in the brain and periphery, the subcellular and cellular distribution. Properties of the binding sites, influence of the composition of the assay medium, binding kinetic properties, receptor regulation in vivo. Identity of the binding sites, differences between site for various 3 H-ligands, pharmacological specificity of the membranous binding sites, chemical composition of the macromolecular complex constituting the binding site. Function of the receptor. Binding affinities of 44 compounds were measured in binding assays using 3 H-spiperone and 3 H-LSD with rat frontal cortex membrane preparations and using 3 H-5-HT and 3 H-LSD with rat hippocampal membrane preparations

Study of the production of the radiopharmaceutical {sup 18}F-FLT in automated system: contribution for process validation; Estudo da producao do radiofarmaco FLT-{sup 18}F em sistema automatizado: contribuicao para a validacao do processo

Energy Technology Data Exchange (ETDEWEB)

Zanette, Camila

2013-07-01

Radiopharmaceutical {sup 18}F-FLT is a thymidine nucleoside analogue and a promising tumor proliferation marker for PET images. The synthesis of this radiopharmaceutical is not simple, and often has low yields. This radiopharmaceutical has already been studied for some years; however, there is no production, nor are there clinical studies in Brazil. The study of the production process and its compliance with the guidelines of Good Manufacturing Practices (ANVISA) are of extreme importance. This study aimed to investigate the synthesis of this radiopharmaceutical, evaluate methods of quality control that will be used in future production routines, perform cytotoxicity studies, biodistribution studies and PET imaging in animals, thereby contributing to the development and elaboration of the process validation protocol and to the establishment of analytical methods to be used during production routines. Initially, we studied the synthesis and production of {sup 18}F-FLT, with the evaluation of three different temperatures of radiolabeling to check the behavior of the radiochemical yield and stability of the nal product. Studies of analytical methodology comprised the analysis of radionuclide identification, determination of chromatographic profiles, radiochemical purity, residual solvents, and pH. In vitro studies of internalization and cytotoxicity were also carried out. In in vivo studies, we evaluated the pharmacokinetics, biodistribution in healthy animals and in animals with tumor models, in addition to PET/CT images in animals with melanomas. The final product had high radiochemical purity and was stable for up to 10 hours after the synthesis, but got a relatively low radiochemical yield, as described in the literature. The tested analytical methods proved suitable for use in the quality control of {sup 18}F-FLT. In in vitro studies, {sup 18}F-FLT showed a significant percentage of binding to tumor cells, and the nonradiolabeled molecule was not considered toxic

Pd-bound functionalized mesoporous silica as active catalyst for Suzuki coupling reaction: Effect of OAcˉ, PPh3 and Clˉ ligands on catalytic activity

Science.gov (United States)

Das, Trisha; Uyama, Hiroshi; Nandi, Mahasweta

2018-04-01

Three new palladium catalysts, PdCat-I, PdCat-II and PdCat-III, immobilized over heterogeneous silica support have been synthesized using different ligands attached to the palladium precursor. The ligands that have been used in this study are acetate, triphenylphosphine and chloride in PdCat-I, PdCat-II and PdCat-III, respectively. The ligands have different effect on stability of the compounds and impart different oxidation states to the metal center. The materials have been characterized by powder X-ray diffraction, nitrogen adsorption-desorption studies, transmission electron microscopy, thermal analysis, and different spectroscopic techniques. The Pd-content of the samples have been determined by ICP-AES analysis. The materials have been used as catalysts for Suzuki coupling reaction of aryl halides with phenylboronic acid under mild conditions. A comparative study has been carried out to ascertain the effect of the nature of different ligands on the outcome of the catalytic reactions. Products have been identified and estimated by 1H NMR and gas chromatography. The results show that the best yields are obtained with the catalyst containing triphenylphosphine as the ligand in methanol. Such type of work to study the effect of ligand on Suzuki coupling reaction over functionalized mesoporous silica heterogeneous catalysts have not been carried out so far.

Luminescent hybrid materials functionalized with lanthanide ethylenodiaminotetraacetate complexes containing β-diketonate as antenna ligands

Energy Technology Data Exchange (ETDEWEB)

Aguiar, Franklin P.; Costa, Israel F.; Espínola, José Geraldo P.; Faustino, Wagner M.; Moura, Jandeilson L. [Departamento de Química-Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Brito, Hermi F.; Paolini, Tiago B. [Departamento de Química Fundamental-Instituto de Química da Universidade de São Paulo, 05508-900 São Paulo, SP (Brazil); Felinto, Maria Cláudia F.C. [Instituto de Pesquisas energéticas e Nucleares-IPEN, 05508-900 São Paulo, SP (Brazil); Teotonio, Ercules E.S., E-mail: teotonioees@quimica.ufpb.br [Departamento de Química-Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil)

2016-02-15

Three organic–inorganic hybrid materials based on silica gel functionalized with (3-aminopropyl)trimethoxysilane (APTS), [3-(2-aminoetilamino)-propil]-trimetoxissilano (DAPTS) and 3-[2-(2-aminoetilamino)etilamino] propiltrimetoxysilane (TAPTS) and subsequently modified with EDTA derivative were prepared by nonhomogeneous route and were then characterized. The resulting materials named SilXN-EDTA (X=1 for APTS, 2 for DAPTS and 3 for TAPTS) were used to obtain new lanthanide Ln{sup 3+}-β-diketonate (Ln{sup 3+}=Eu{sup 3+}, Gd{sup 3+} and Tb{sup 3+}) complexes covalently linked to the functionalized silica gel surfaces (named SilXN-EDTALn-dik, dik=tta, dbm, bzac and acac). The photophysical properties of the new luminescent materials were investigated and compared with those with similar system presenting water molecules coordinated to the lanthanide ions, SilXN-EDTALn-H{sub 2}O. The SilXN-EDTAEu-dik and SilXN-EDTATb-dik systems displayed characteristic red and green luminescence when excited by UV radiation. Furthermore, the quantitative results showed that the emission quantum efficiency (η), experimental intensity parameters Ω{sub 2} and Ω{sub 4}, and Einstein's emission coefficient (A{sub 0J}) of the SilXN-EDTAEu-dik materials were largely dependent on the ligands. Based on the luminescence data, the most efficient intramolecular energy transfer processes were found to the SilXN-EDTAEu-dik (dik: tta and dbm) and SilXN-EDTATb-acac materials, which exhibited more pure emission colors. These materials are promising red and green phosphors, respectively. - Highlights: • New highly luminescent hybrid materials containing lanthanide-EDTA complexes. • The effect of three silylanting agent on the adsorption and luminescent properties has been studied. • The luminescence sensitizing by different β-diketonate ligands have been investigated.

Evaluation of {sup 18}F-FDG and {sup 18}F-FLT for monitoring therapeutic responses of colorectal cancer cells to radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Wang, Hui [Nuclear Medicine Department, The General Hospital of the Chinese People' s Liberation Army and Military Medical Postgraduate College, Beijing 100853 (China); Liu, Bo [Department of Hepatobiliary Surgery, The General Hospital of the Chinese People' s Liberation Army and Military Medical Postgraduate College, Beijing 100853 (China); Tian, Jiahe, E-mail: tianjh@vip.sina.com [Nuclear Medicine Department, The General Hospital of the Chinese People' s Liberation Army and Military Medical Postgraduate College, Beijing 100853 (China); Xu, Baixuan; Zhang, Jinming [Nuclear Medicine Department, The General Hospital of the Chinese People' s Liberation Army and Military Medical Postgraduate College, Beijing 100853 (China); Qu, Baolin [Department of Radiation Oncology, The General Hospital of the Chinese People' s Liberation Army and Military Medical Postgraduate College, Beijing 100853 (China); Chen, Yingmao [Nuclear Medicine Department, The General Hospital of the Chinese People' s Liberation Army and Military Medical Postgraduate College, Beijing 100853 (China)

2013-09-15

In order to compare the efficacy of {sup 18}F-fluorothymidine (FLT) and {sup 18}F-fluorodeoxyglucose (FDG) for monitoring early responses to irradiation, two human colorectal cancer (CRC) cell lines SW480 and SW620, which were derived from the primary lesions and the metastatic lymph node, underwent X-ray irradiation of 0, 10, or 20 Gy and were examined at 0, 24 and 72 h After irradiation, reduced proliferation of both SW480 and SW620 cells was observed in a dose-dependent manner (P < 0.001), G0-G1 arrest was also noted in both cell types after 72 h in the 20 Gy group (P < 0.001). Although increased apoptosis was observed in both cell lines after irradiation (P < 0.001), a greater percentage of SW480 cells underwent apoptosis in response to irradiation than SW620 cells. Increased Hsp27 and decreased integrin β{sub 3}, Ki67 and VEGFR2 expression was observed over time via immunocytochemistry and Western blot analysis (P < 0.001), however, no significant changes were noted in response to irradiation. Finally, reduced uptake of {sup 18}F-FLT by SW480 or SW620 cells was observed at 24-h post-irradiation, however, reduced {sup 18}F-FDG uptake was only observed after 72 h. Therefore, we conclude that {sup 18}F-FLT is a more suitable positron emission tomography (PET) tracer for monitoring early responses to irradiation in primary and metastatic lymph node CRC cells.

GITR ligand-costimulation activates effector and regulatory functions of CD4+ T cells

International Nuclear Information System (INIS)

Igarashi, Hanna; Cao, Yujia; Iwai, Hideyuki; Piao, Jinhua; Kamimura, Yosuke; Hashiguchi, Masaaki; Amagasa, Teruo; Azuma, Miyuki

2008-01-01

Engagement of glucocorticoid-induced TNFR-related protein (GITR) enables the costimulation of both CD25 - CD4 + effector (Teff) and CD25 + CD4 + regulatory (Treg) cells; however, the effects of GITR-costimulation on Treg function remain controversial. In this study, we examined the effects of GITR ligand (GITRL) binding on the respective functions of CD4 + T cells. GITRL-P815 transfectants efficiently augmented anti-CD3-induced proliferation and cytokine production by Teff cells. Proliferation and IL-10 production in Treg were also enhanced by GITRL transfectants when exogenous IL-2 and stronger CD3 stimulation was provided. Concomitant GITRL-costimulation of Teff and Treg converted the anergic state of Treg into a proliferating state, maintaining and augmenting their function. Thus, GITRL-costimulation augments both effector and regulatory functions of CD4 + T cells. Our results suggest that highly activated and increased ratios of Treg reverse the immune-enhancing effects of GITRL-costimulation in Teff, which may be problematic for therapeutic applications using strong GITR agonists

The influences of sensitivity of ligand in determination of fluors with LaF3

International Nuclear Information System (INIS)

Muzakky; Lahagu, F.; Djawahiri, H.M.; Susiaturi, E.

1996-01-01

The influences of acetate and carbonate ligand as a binder of uranium in uranium-tetra fluoride solution, with 0,1 M HNO 3 acid condition was been studied. The aim of binding is to looses of uranium from UO 2 (F 4 ) 2- compound, so the free of fluoride were able detected with LaF 3 membrane electrode on potentiometric method. Base on the free of Fluoride, acetate ligand was more sensitive than carbonate ligand. The addition method was able to prevented influent of HF species in high acidity was realized. The method was use to determination of Fluoride in C oncentrated Uranium , and yield are 1,215x10 -5 M±1,957x10 -4 in acetate ligand and 3,957x10 -5 M±2,57x10 -4 in carbonate ligand. (author)

Influence factor on automated synthesis yield of 3'-deoxy-3'-[18F] fluorothymidine

International Nuclear Information System (INIS)

Zhang Jinming; Tian Jiahe; Liu Changbin; Liu Jian; Luo Zhigang

2009-01-01

3'-deoxy-3'-[ 18 F] fluorothymidine ( 18 F-FLT) was prepared from N-BOC precursor to improve the synthesis yield, chemical purity and radiochemical purity of 18 F-FLT by home-made automated synthesis module. The results showed that residual water in synthesis system and the amount of precursor could affect the synthesis yield dramatically. The more the amount of precursor, the higher the synthesis yield of N-BOC. The residual water can decrease the synthesis yield. In the presence of excess base, the precursor was consumed by elimination before substitution was completed. The precursor to base was optimal in 1 to 1. The balance of semi-preparatiove HPLC Column can affect purified the final 18 F-FLT product. The chemical purity of 18 F-FLT could be decreased with 8% EtOH as mobile phase in semi-preparatiove HPLC. The high chemical purity, radiochemical purity and synthesis yield could be obtained by optimized the parameter of synthesis with home-made automated synthesis module. (authors)

Serum concentrations of soluble Flt-1 are decreased among women with a viable fetus and no symptoms of miscarriage destined for pregnancy loss.

Directory of Open Access Journals (Sweden)

Tu'uhevaha J Kaitu'u-Lino

Full Text Available Miscarriage is the most common complication of pregnancy. Pre-clinical miscarriage has an estimated incidence of 30%, whilst clinical miscarriage has an incidence of 12-15%. Two thirds of pregnancies lost to miscarriage are believed to be attributable to defective placentation, thus a number of studies have sought to identify markers of defective placentation that could be used as clinical biomarkers of miscarriage. Decreased soluble FMS-like tyrosine kinase-1 (sFlt1, placental growth factor (PlGF, and soluble endoglin (sEng in the maternal circulation during the first trimester have recently been proposed as potential markers of pregnancy loss. However, in these studies clinical samples were only obtained once women had presented with symptoms of miscarriage. In this study we prospectively screened serum samples collected from asymptomatic women with a viable fetus. We assessed maternal serum levels of sFlt1, PlGF and sEng across the first trimester of normal pregnancy and compared levels between women who continued to a live birth, to those who subsequently miscarried. Both sFlt1 and PlGF significantly (p≤0.05 increased across gestation in normal pregnancy with serum levels rising from 0.65±0.12 ng/ml at 6 weeks to 1.85±0.24 ng/ml at 12 weeks for sFlt1, and 57.2±19.2 pg/ml to 106±22.7 pg/ml for PlGF. sEng remained unchanged throughout the the first trimester. Importantly we detected a significant (35%, p≤0.05 decrease in sFlt1 levels between our control and miscarriage cohort, however there was significant overlap between cases and controls, suggesting serum sFlt1 is unlikely to be useful as a clinical biomarker in asymptomatic women. Nevertheless, our data suggests a dysregulation of angiogenic factors may be involved in the pathophysiology of miscarriage.

PatchSurfers: Two methods for local molecular property-based binding ligand prediction.

Science.gov (United States)

Shin, Woong-Hee; Bures, Mark Gregory; Kihara, Daisuke

2016-01-15

Protein function prediction is an active area of research in computational biology. Function prediction can help biologists make hypotheses for characterization of genes and help interpret biological assays, and thus is a productive area for collaboration between experimental and computational biologists. Among various function prediction methods, predicting binding ligand molecules for a target protein is an important class because ligand binding events for a protein are usually closely intertwined with the proteins' biological function, and also because predicted binding ligands can often be directly tested by biochemical assays. Binding ligand prediction methods can be classified into two types: those which are based on protein-protein (or pocket-pocket) comparison, and those that compare a target pocket directly to ligands. Recently, our group proposed two computational binding ligand prediction methods, Patch-Surfer, which is a pocket-pocket comparison method, and PL-PatchSurfer, which compares a pocket to ligand molecules. The two programs apply surface patch-based descriptions to calculate similarity or complementarity between molecules. A surface patch is characterized by physicochemical properties such as shape, hydrophobicity, and electrostatic potentials. These properties on the surface are represented using three-dimensional Zernike descriptors (3DZD), which are based on a series expansion of a 3 dimensional function. Utilizing 3DZD for describing the physicochemical properties has two main advantages: (1) rotational invariance and (2) fast comparison. Here, we introduce Patch-Surfer and PL-PatchSurfer with an emphasis on PL-PatchSurfer, which is more recently developed. Illustrative examples of PL-PatchSurfer performance on binding ligand prediction as well as virtual drug screening are also provided. Copyright © 2015 Elsevier Inc. All rights reserved.

Molecular mechanism of ligand recognition by NR3 subtype glutamate receptors

Energy Technology Data Exchange (ETDEWEB)

Yao, Yongneng; Harrison, Chris B.; Freddolino, Peter L.; Schulten, Klaus; Mayer, Mark L. (UIUC); (NIH)

2008-10-27

NR3 subtype glutamate receptors have a unique developmental expression profile, but are the least well-characterized members of the NMDA receptor gene family, which have key roles in synaptic plasticity and brain development. Using ligand binding assays, crystallographic analysis, and all atom MD simulations, we investigate mechanisms underlying the binding by NR3A and NR3B of glycine and D-serine, which are candidate neurotransmitters for NMDA receptors containing NR3 subunits. The ligand binding domains of both NR3 subunits adopt a similar extent of domain closure as found in the corresponding NR1 complexes, but have a unique loop 1 structure distinct from that in all other glutamate receptor ion channels. Within their ligand binding pockets, NR3A and NR3B have strikingly different hydrogen bonding networks and solvent structures from those found in NR1, and fail to undergo a conformational rearrangement observed in NR1 upon binding the partial agonist ACPC. MD simulations revealed numerous interdomain contacts, which stabilize the agonist-bound closed-cleft conformation, and a novel twisting motion for the loop 1 helix that is unique in NR3 subunits.

Elucidating the role of surface passivating ligand structural parameters in hole wave function delocalization in semiconductor cluster molecules.

Science.gov (United States)

Teunis, Meghan B; Nagaraju, Mulpuri; Dutta, Poulami; Pu, Jingzhi; Muhoberac, Barry B; Sardar, Rajesh; Agarwal, Mangilal

2017-09-28

This article describes the mechanisms underlying electronic interactions between surface passivating ligands and (CdSe) 34 semiconductor cluster molecules (SCMs) that facilitate band-gap engineering through the delocalization of hole wave functions without altering their inorganic core. We show here both experimentally and through density functional theory calculations that the expansion of the hole wave function beyond the SCM boundary into the ligand monolayer depends not only on the pre-binding energetic alignment of interfacial orbitals between the SCM and surface passivating ligands but is also strongly influenced by definable ligand structural parameters such as the extent of their π-conjugation [π-delocalization energy; pyrene (Py), anthracene (Anth), naphthalene (Naph), and phenyl (Ph)], binding mode [dithiocarbamate (DTC, -NH-CS 2 - ), carboxylate (-COO - ), and amine (-NH 2 )], and binding head group [-SH, -SeH, and -TeH]. We observe an unprecedentedly large ∼650 meV red-shift in the lowest energy optical absorption band of (CdSe) 34 SCMs upon passivating their surface with Py-DTC ligands and the trend is found to be Ph- wave function delocalization rather than carrier trapping and/or phonon-mediated relaxation. Taken together, knowledge of how ligands electronically interact with the SCM surface is crucial to semiconductor nanomaterial research in general because it allows the tuning of electronic properties of nanomaterials for better charge separation and enhanced charge transfer, which in turn will increase optoelectronic device and photocatalytic efficiencies.

3,4-Dimethyl diphenyldithiophosphate of mononuclear cobalt(II) with N-donor ligands: Synthesis, structural characterization, DFT and antibacterial studies

Science.gov (United States)

Kumar, Sandeep; Kour, Gurpreet; Schreckenbach, Georg; Andotra, Savit; Hundal, Geeta; Sharma, Vishal; Jaglan, Sundeep; Pandey, Sushil K.

2017-08-01

3,4-Dimethyl diphenyldithiophosphate of cobalt(II) with N-donor ligands [{(ArO)2PS2}2CoL2] [Ar = 3,4-(CH3)2C6H3 (1-3); L = C5H5N (1), 3,4-(CH3)2C5H3N (2) and 4-(C2H5)C5H4N (3)] have been synthesized and characterized by elemental analyses, infrared spectroscopy (IR), powder X-ray diffraction (PXRD) and single crystal X-ray analysis. Complex 1 crystallizes in the monoclinic space group P21/n whereas complexes 2 and 3 crystallize in the triclinic space group Pbar1. The crystal structures of complexes 1-3 reveal mononuclear units with the Co(II) center chelated in bidentate fashion by four S atoms of the two diphenyldithiophosphate ligands. The N atoms from two donor ligands are axially coordinated, leading to distorted octahedral geometry around Co(II). The complexes have been optimized using density functional theory (DFT), structural parameters have been calculated, and the energy gaps of the frontier orbitals (HOMO-LUMO) have been predicted. Mayer bond orders have also been calculated. Structural parameters from the crystallographic and DFT studies are in good agreement with each other. To explore the biological potential, complexes were evaluated for their antibacterial activity against three bacterial strains. The bacterial growth inhibition capacity of the ligand and complexes followed the order of 3 > 2 > 1 > L1.

A General Ligand Design for Gold Catalysis allowing Ligand-Directed Anti Nucleophilic Attack of Alkynes

Science.gov (United States)

Wang, Yanzhao; Wang, Zhixun; Li, Yuxue; Wu, Gongde; Cao, Zheng; Zhang, Liming

2014-01-01

Most homogenous gold catalyses demand ≥0.5 mol % catalyst loading. Due to the high cost of gold, these reactions are unlikely to be applicable in medium or large scale applications. Here we disclose a novel ligand design based on the privileged biphenyl-2-phosphine framework that offers a potentially general approach to dramatically lowering catalyst loading. In this design, an amide group at the 3’ position of the ligand framework directs and promotes nucleophilic attack at the ligand gold complex-activated alkyne, which is unprecedented in homogeneous gold catalysis considering the spatial challenge of using ligand to reach antiapproaching nucleophile in a linear P-Au-alkyne centroid structure. With such a ligand, the gold(I) complex becomes highly efficient in catalyzing acid addition to alkynes, with a turnover number up to 99,000. Density functional theory calculations support the role of the amide moiety in directing the attack of carboxylic acid via hydrogen bonding. PMID:24704803

In vitro modulation of radiation-induced FAS-related apoptosis in CD34{sup +} progenitor cells by combination cytokines; Reduction de l'apoptose radio-induite impliquant le recepteur FAS au niveau des cellules hematopoietiques CD34{sup +} par une combinaison de cytokines

Energy Technology Data Exchange (ETDEWEB)

Drouet, M.; Mathieu, J.; Grenier, N.; Soutif, A.; Herodin, F

1998-07-01

Combination cytokines such as SCF, Flt-3 ligand, IL-3 and thrombopoietin can modulate Fas mRNA expression by in vitro irradiated CD34{sup +} cells which results in a moderate decrease of apoptotic ratio and an improved rate of clonogenicity of the irradiated progenitors. (authors)

Water oxidation catalyzed by mononuclear ruthenium complexes with a 2,2'-bipyridine-6,6'-dicarboxylate (bda) ligand: how ligand environment influences the catalytic behavior.

Science.gov (United States)

Staehle, Robert; Tong, Lianpeng; Wang, Lei; Duan, Lele; Fischer, Andreas; Ahlquist, Mårten S G; Sun, Licheng; Rau, Sven

2014-02-03

A new water oxidation catalyst [Ru(III)(bda)(mmi)(OH2)](CF3SO3) (2, H2bda = 2,2'-bipyridine-6,6'-dicarboxylic acid; mmi = 1,3-dimethylimidazolium-2-ylidene) containing an axial N-heterocyclic carbene ligand and one aqua ligand was synthesized and fully characterized. The kinetics of catalytic water oxidation by 2 were measured using stopped-flow technique, and key intermediates in the catalytic cycle were probed by density functional theory calculations. While analogous Ru-bda water oxidation catalysts [Ru(bda)L2] (L = pyridyl ligands) are supposed to catalyze water oxidation through a bimolecular coupling pathway, our study points out that 2, surprisingly, undergoes a single-site water nucleophilic attack (acid-base) pathway. The diversion of catalytic mechanisms is mainly ascribed to the different ligand environments, from nonaqua ligands to an aqua ligand. Findings in this work provide some critical proof for our previous hypothesis about how alternation of ancillary ligands of water oxidation catalysts influences their catalytic efficiency.

LigandRFs: random forest ensemble to identify ligand-binding residues from sequence information alone

KAUST Repository

Chen, Peng; Huang, Jianhua Z; Gao, Xin

2014-01-01

Protein-ligand binding is important for some proteins to perform their functions. Protein-ligand binding sites are the residues of proteins that physically bind to ligands. Despite of the recent advances in computational prediction

A facile and rapid automated synthesis of 3'-deoxy-3'-[18F]fluorothymidine

International Nuclear Information System (INIS)

Tang Ganghua; Tang Xiaolan; Wen Fuhua; Wang Mingfang; Li Baoyuan

2010-01-01

Aim: To develop a simplified and fully automated synthesis procedure of 3'-deoxy-3'-[ 18 F]fluorothymidine ([ 18 F]FLT) using PET-MF-2V-IT-I synthesis module. Methods: Synthesis of [ 18 F]FLT was performed using PET-MF-2V-IT-I synthesis module by one-pot two-step reaction procedure, including nucleophilic fluorination of 3-N-t-butoxycarbonyl-1-[5'-O-(4,4'-dimethoxy triphenylmethyl)-2'-deoxy-3'-O-(4-nitrobenzenesulfonyl) -β-D-threopentofuranosyl]thymine (15 mg) as the precursor molecule with [ 18 F]fluoride, and subsequent hydrolysis of the protecting group with 1.0 M HCl at the same reaction vessel and purification with SEP PAK cartridges instead of the HPLC system. Results: The automated synthesis of [ 18 F]FLT with SEP PAK purification gave corrected radiochemical yield of 23.2±2.6% (n=6, uncorrected yield: 16-22%) and radiochemical purity of >97% within the total synthesis time of 35 min. Conclusion: The fully one-pot automated synthesis procedure with SEP PAK purification can be applied to the fully automated synthesis of [ 18 F]FLT using commercial [ 18 F]FDG synthesis module.

Can 3'-Deoxy-3'-((18)F) Fluorothymidine Out Perform 2-Deoxy-2-((18)F) Fluoro-D-Glucose Positron Emission Tomography/Computed Tomography in the Diagnosis of Cervical Lymphadenopathy in Patients With Oral/Head and Neck Cancer?

Science.gov (United States)

Schaefferkoetter, Joshua D; Carlson, Eric R; Heidel, Robert E

2015-07-01

The present study investigated the performance of cellular metabolism imaging with 2-deoxy-2-((18)F) fluoro-D-glucose (FDG) versus cellular proliferation imaging with 3'-deoxy-3'-((18)F) fluorothymidine (FLT) in the detection of cervical lymph node metastases in oral/head and neck cancer. We conducted a prospective cohort study to assess a head-to-head performance of FLT imaging and clinical FDG imaging for characterizing cervical lymph node metastases in patients with squamous cell carcinoma (SCC) of the oral/head and neck region. The primary predictor variable of the study was the presence of FDG or FLT avidity within the cervical lymph nodes. The primary outcome variable was the histologic presence of metastatic SCC in the cervical lymph nodes. The performance was reported in terms of the sensitivity, specificity, accuracy, and positive and negative predictive values. The overall accuracy for discriminating positive from negative lymph nodes was evaluated as a function of the positron emission tomography (PET) standardized uptake value (SUV). Receiver operating characteristic (ROC) analyses were performed for both tracers. Eleven patients undergoing surgical resection of SCC of the oral/head and neck region underwent preoperative FDG and FLT PET-computed tomography (CT) scans on separate days. The interpretation of the FDG PET-CT imaging resulted in sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 43.2, 99.5, 94.4, 88.9, and 94.7%, respectively. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for FLT PET-CT imaging was 75.7, 99.2, 97.1, 90.3, and 97.7%, respectively. The areas under the curve for the ROC curves were 0.9 and 0.84 for FDG and FLT, respectively. Poor correlation was observed between the SUV for FDG and FLT within the lymph nodes and tumors. FLT showed better overall performance for detecting lymphadenopathy on qualitative assessment within the total

Comparison of (18)F-FET and (18)F-FLT small animal PET for the assessment of anti-VEGF treatment response in an orthotopic model of glioblastoma

DEFF Research Database (Denmark)

Nedergaard, Mette Kjoelhede; Michaelsen, Signe Regner; Perryman, Lara

2016-01-01

was to compare FLT and FET PET for the assessment of anti-VEGF response in glioblastoma xenografts. METHODS: Xenografts with confirmed intracranial glioblastoma were treated with anti-VEGF therapy (B20-4.1) or saline as control. Weekly bioluminescence imaging (BLI), FLT and FET PET/CT were used to follow....... Furthermore, we found a significantly lower MVD in the anti-VEGF group as compared to the control group. However, we found no difference in the Ki67 proliferation index or mean survival time. CONCLUSION: FET appears to be a more sensitive tracer than FLT to measure early response to anti-VEGF therapy with PET...

Peroxisome proliferator-activated receptor α ligands and modulators from dietary compounds: Types, screening methods and functions.

Science.gov (United States)

Yang, Haixia; Xiao, Lei; Wang, Nanping

2017-04-01

Peroxisome proliferator-activated receptor α (PPARα) plays a key role in lipid metabolism and glucose homeostasis and a crucial role in the prevention and treatment of metabolic diseases. Natural dietary compounds, including nutrients and phytochemicals, are PPARα ligands or modulators. High-throughput screening assays have been developed to screen for PPARα ligands and modulators in our diet. In the present review, we discuss recent advances in our knowledge of PPARα, including its structure, function, and ligand and modulator screening assays, and summarize the different types of dietary PPARα ligands and modulators. © 2016 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

Predicting Efficient Antenna Ligands for Tb(III) Emission

Energy Technology Data Exchange (ETDEWEB)

Samuel, Amanda P.S.; Xu, Jide; Raymond, Kenneth

2008-10-06

A series of highly luminescent Tb(III) complexes of para-substituted 2-hydroxyisophthalamide ligands (5LI-IAM-X) has been prepared (X = H, CH{sub 3}, (C=O)NHCH{sub 3}, SO{sub 3}{sup -}, NO{sub 2}, OCH{sub 3}, F, Cl, Br) to probe the effect of substituting the isophthalamide ring on ligand and Tb(III) emission in order to establish a method for predicting the effects of chromophore modification on Tb(III) luminescence. The energies of the ligand singlet and triplet excited states are found to increase linearly with the {pi}-withdrawing ability of the substituent. The experimental results are supported by time-dependent density functional theory (TD-DFT) calculations performed on model systems, which predict ligand singlet and triplet energies within {approx}5% of the experimental values. The quantum yield ({Phi}) values of the Tb(III) complex increases with the triplet energy of the ligand, which is in part due to the decreased non-radiative deactivation caused by thermal repopulation of the triplet. Together, the experimental and theoretical results serve as a predictive tool that can be used to guide the synthesis of ligands used to sensitize lanthanide luminescence.

Functional glass slides for in vitro evaluation of interactions between osteosarcoma TE85 cells and mineral-binding ligands

Energy Technology Data Exchange (ETDEWEB)

Song, Jie; Chen, Julia; Klapperich, Catherine M.; Eng, Vincent; Bertozzi, Carolyn R.

2004-07-20

Primary amine-functionalized glass slides obtained through a multi-step plasma treatment were conjugated with anionic amino acids that are frequently found as mineral binding elements in acidic extracellular matrix components of natural bone. The modified glass surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. Human osteosarcoma TE85 cells were cultured on these functionalized slides and analyses on both protein and gene expression levels were performed to probe the ''biocompatibility'' of the surface ligands. Cell attachment and proliferation on anionic surfaces were either better than or comparable to those of cells cultured on tissue culture polystyrene (TCPS). The modified glass surfaces promoted the expression of osteocalcin, alkaline phosphatase activity and ECM proteins such as fibronectin and vitronectin under differentiation culture conditions. Transcript analysis using gene chip microarrays confirmed that culturing TE85 cells on anionic surfaces did not activate apoptotic pathways. Collectively, these results suggest that the potential mineral-binding anionic ligands examined here do not exert significant adverse effects on the expression of important osteogenic markers of TE85 cells. This work paves the way for the incorporation of these ligands into 3-dimensional artificial bone-like scaffolds.

3'-Deoxy-3'-18F-fluorothymidine positron emission tomography as an early predictor of disease progression in patients with advanced and metastatic pancreatic cancer

International Nuclear Information System (INIS)

Challapalli, Amarnath; Barwick, Tara; Merchant, Shairoz; Pearson, Rachel A.; Howell, Elizabeth C.; Maxwell, Ross J.; Mauri, Francesco; Sumpter, Katherine; Aboagye, Eric O.; Sharma, Rohini

2015-01-01

3'-Deoxy-3'- 18 F-fluorothymidine (FLT) positron emission tomography (PET) has limited utility in abdominal imaging due to high physiological hepatic uptake of tracer. We evaluated FLT PET/CT combined with a temporal-intensity information-based voxel-clustering approach termed kinetic spatial filtering (FLT PET/CT KSF ) for early prediction of response and survival outcomes in locally advanced and metastatic pancreatic cancer patients receiving gemcitabine-based chemotherapy. Dynamic FLT PET/CT data were collected before and 3 weeks after the first cycle of chemotherapy. Changes in tumour FLT PET/CT variables were determined. The primary end point was RECIST 1.1 response on contrast-enhanced CT after 3 months of therapy. Twenty patients were included. Visual distinction between tumours and normal pancreas was seen in FLT PET KSF images. All target lesions (>2 cm), including all primary pancreatic tumours, were visualised. Of the 11 liver metastases, 3 (<2 cm) were not visible after kinetic filtering. Of the 20 patients, 7 progressed (35 %). Maximum standardised uptake value at 60 min post-injection (SUV 60,max ) significantly increased in patients with disease progression (p = 0.04). Receiver-operating characteristic curve analysis indicated that a threshold of SUV 60,max increase of ≥ 12 % resulted in sensitivity, specificity and positive predictive value (PPV) of 71, 100 and 100 %, respectively [area under the curve (AUC) 0.90, p = 0.0001], to predict patients with disease progression. Changes in SUV 60,max were not predictive of survival. FLT PET/CT detected changes in proliferation, with early increase in SUV 60,max predicting progressive disease with a high specificity and PPV. Therefore, FLT PET/CT could be used as an early response biomarker for gemcitabine-based chemotherapy, to select a poor prognostic group who may benefit from novel therapeutic agents in advanced and metastatic pancreatic cancer. (orig.)

Interactions of human hemoglobin with charged ligand-functionalized iron oxide nanoparticles and effect of counterions

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Goutam, E-mail: ghoshg@yahoo.com [UGC-DAE Consortium for Scientific Research, Mumbai Centre (India); Panicker, Lata [Bhabha Atomic Research Centre, Solid State Physics Division (India)

2014-12-15

Human hemoglobin is an important metalloprotein. It has tetrameric structure with each subunit containing a ‘heme’ group which carries oxygen and carbon dioxide in blood. In this work, we have investigated the interactions of human hemoglobin (Hb) with charged ligand-functionalized iron oxide nanoparticles and the effect of counterions, in aqueous medium. Several techniques like DLS and ζ-potential measurements, UV–vis, fluorescence, and CD spectroscopy have been used to characterize the interaction. The nanoparticle size was measured to be in the range of 20–30 nm. Our results indicated the binding of Hb with both positively as well as negatively charged ligand-functionalized iron oxide nanoparticles in neutral aqueous medium which was driven by the electrostatic and the hydrophobic interactions. The electrostatic binding interaction was not seen in phosphate buffer at pH 7.4. We have also observed that the ‘heme’ groups of Hb remained unaffected on binding with charged nanoparticles, suggesting the utility of the charged ligand-functionalized nanoparticles in biomedical applications.

Structure and function of the selectin ligand PSGL-1

Directory of Open Access Journals (Sweden)

Cummings R.D.

1999-01-01

Full Text Available P-selectin glycoprotein ligand-1 (PSGL-1 is a dimeric mucin-like 120-kDa glycoprotein on leukocyte surfaces that binds to P- and L-selectin and promotes cell adhesion in the inflammatory response. The extreme amino terminal extracellular domain of PSGL-1 is critical for these interactions, based on site-directed mutagenesis, blocking monoclonal antibodies, and biochemical analyses. The current hypothesis is that for high affinity interactions with P-selectin, PSGL-1 must contain O-glycans with a core-2 branched motif containing the sialyl Lewis x antigen (NeuAca2®3Galß1®4[Fuca1®3]GlcNAcß1®R. In addition, high affinity interactions require the co-expression of tyrosine sulfate on tyrosine residues near the critical O-glycan structure. This review addresses the biochemical evidence for this hypothesis and the evidence that PSGL-1 is an important in vivo ligand for cell adhesion.

3'-Deoxy-3'-{sup 18}F-fluorothymidine positron emission tomography as an early predictor of disease progression in patients with advanced and metastatic pancreatic cancer

Energy Technology Data Exchange (ETDEWEB)

Challapalli, Amarnath; Barwick, Tara; Merchant, Shairoz [Imperial College London (ICL), Department of Surgery and Cancer, London (United Kingdom); Pearson, Rachel A.; Howell, Elizabeth C.; Maxwell, Ross J. [Newcastle University, Northern Institute for Cancer Research, Newcastle (United Kingdom); Mauri, Francesco [Imperial College Healthcare NHS Trust, Department of Pathology, London (United Kingdom); Sumpter, Katherine [Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, London (United Kingdom); Aboagye, Eric O. [Imperial College London (ICL), Department of Surgery and Cancer, London (United Kingdom); ICL, Hammersmith Hospital, Department of Surgery and Cancer, London (United Kingdom); Sharma, Rohini [ICL, Department of Investigative Medicine, London (United Kingdom)

2015-05-01

3'-Deoxy-3'-{sup 18}F-fluorothymidine (FLT) positron emission tomography (PET) has limited utility in abdominal imaging due to high physiological hepatic uptake of tracer. We evaluated FLT PET/CT combined with a temporal-intensity information-based voxel-clustering approach termed kinetic spatial filtering (FLT PET/CT{sub KSF}) for early prediction of response and survival outcomes in locally advanced and metastatic pancreatic cancer patients receiving gemcitabine-based chemotherapy. Dynamic FLT PET/CT data were collected before and 3 weeks after the first cycle of chemotherapy. Changes in tumour FLT PET/CT variables were determined. The primary end point was RECIST 1.1 response on contrast-enhanced CT after 3 months of therapy. Twenty patients were included. Visual distinction between tumours and normal pancreas was seen in FLT PET{sub KSF} images. All target lesions (>2 cm), including all primary pancreatic tumours, were visualised. Of the 11 liver metastases, 3 (<2 cm) were not visible after kinetic filtering. Of the 20 patients, 7 progressed (35 %). Maximum standardised uptake value at 60 min post-injection (SUV{sub 60,max}) significantly increased in patients with disease progression (p = 0.04). Receiver-operating characteristic curve analysis indicated that a threshold of SUV{sub 60,max} increase of ≥ 12 % resulted in sensitivity, specificity and positive predictive value (PPV) of 71, 100 and 100 %, respectively [area under the curve (AUC) 0.90, p = 0.0001], to predict patients with disease progression. Changes in SUV{sub 60,max} were not predictive of survival. FLT PET/CT detected changes in proliferation, with early increase in SUV{sub 60,max} predicting progressive disease with a high specificity and PPV. Therefore, FLT PET/CT could be used as an early response biomarker for gemcitabine-based chemotherapy, to select a poor prognostic group who may benefit from novel therapeutic agents in advanced and metastatic pancreatic cancer. (orig.)

Aryl hydrocarbon receptor ligand effects in RBL2H3 cells

DEFF Research Database (Denmark)

Maaetoft-Udsen, Kristina; Shimoda, Lori M. N.; Frøkiær, Hanne

2012-01-01

The aryl hydrocarbon receptor (AHR) mediates toxic effects of dioxin and xenobiotic metabolism. AHR has an emerging role in the immune system, but its physiological ligands and functional role in immunocytes remain poorly understood. Mast cells are immunocytes that are central to inflammatory...

AMPA receptor ligands

DEFF Research Database (Denmark)

Strømgaard, Kristian; Mellor, Ian

2004-01-01

Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPAR), subtype of the ionotropic glutamate receptors (IGRs), mediate fast synaptic transmission in the central nervous system (CNS), and are involved in many neurological disorders, as well as being a key player in the f......Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPAR), subtype of the ionotropic glutamate receptors (IGRs), mediate fast synaptic transmission in the central nervous system (CNS), and are involved in many neurological disorders, as well as being a key player...... in the formation of memory. Hence, ligands affecting AMPARs are highly important for the study of the structure and function of this receptor, and in this regard polyamine-based ligands, particularly polyamine toxins, are unique as they selectively block Ca2+ -permeable AMPARs. Indeed, endogenous intracellular...

Concise and diversity-oriented synthesis of ligand arm-functionalized azoamides.

Science.gov (United States)

Urankar, Damijana; Kosmrlj, Janez

2008-01-01

Azoamides, previously established as bioactive intracellular GSH-depleting agents, were decorated with a terminal alkyne moiety to 4 and then were transformed, by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC), into different ligand-arm functionalized azoamides 6. Azides 5 having ligand-arms amenable for binding to platinum(II) were selected for this study. Because, for the fragile azoamides 4, the typically employed reaction conditions for CuAAC failed, several alternative solvents and copper catalysts were tested. Excellent results were obtained with copper(II) sulfate pentahydrate/metallic copper and especially with heterogeneous catalysts, such as copper-in-charcoal, cupric oxide, and cuprous oxide. The heterogeneous catalysts were employed to obtain the desired products in almost quantitative yields by a simple three-step "stir-filter-evaporate" protocol with no or negligible contamination with copper impurities. This is of particular importance because compounds 6 have been designed for coordination.

Synthesis and characterization of monomeric and polymeric Cu(II) complexes of 3,4-ethylenedioxythiophene-functionalized with cyclam ligand

International Nuclear Information System (INIS)

Velauthamurty, Kuhamoorthy; Higgins, Simon J.; Rajapakse, R.M. Gamini; Bandara, H.M.N.; Shimomura, Masaru

2010-01-01

A functionalized EDOT derivative with 1,4,8,11-tetraazacyclotetradecane (cyclam) ligand pendant to the ethylene bridge (4) and its complexes [M(4)(BF 4 ) 2 ], where M(II) = Cu(II), was prepared and characterized. Their electrochemical copolymerization with EDOT was studied. The electro-co-polymerized films were characterized by electrochemical methods, X-ray photoelectron spectroscopy and by X-ray fluorescence spectroscopy. The co-polymerization method was found to afford a good control of the metal concentration in the polymer matrix and represents a good technique for preparing electronically conductive polymers containing redox-active metal complexes.

Routinely automated production of 3'-deoxy-3'-[18F] fluorothymidine as a specific molecular imaging probe of tumor cell proliferation

International Nuclear Information System (INIS)

Wang Mingwei; Zhang Yingjian; Zhang Yongping

2011-01-01

This work was aimed at developing a routine for automated production of 3'-deoxy-3'-[ 18 F]fluorothymidine ( 18 F-FLT), a specific molecular imaging probe of tumor cell proliferation, using one-pot two-step strategy and an upgraded Explora GN module integrated with a semi-preparative HPLC system. Firstly, the nucleophilic [ 18 F] radiofluorination of precursor BDNT with activated 18 F ion was carried out at 120 degree C for 5 min to yield the labeled intermediate 18 F-BDFT. Secondly, the acidic hydrolysis of 18 F-BDFT was run at 110 degree C for 5 min to produce 18 F-FLT after addition of HCl, and 18 F-FLT was purified by HPLC. This automated production of 18 F-FLT is of fast, reliable and multi-run features, being completed within 65 min with radiochemical yield of 15%-25% (without decay correction). The quality control of 18 F-FLT was identical with the radiopharmaceutical requirements, especiallly the radiochemical purity of greater than 99% and high chemical purity and specific activity own to HPLC purification. (authors)

Calculating the mean time to capture for tethered ligands and its effect on the chemical equilibrium of bound ligand pairs.

Science.gov (United States)

Shen, Lu; Decker, Caitlin G; Maynard, Heather D; Levine, Alex J

2016-09-01

We present here the calculation of the mean time to capture of a tethered ligand to the receptor. This calculation is then used to determine the shift in the partitioning between (1) free, (2) singly bound, and (3) doubly bound ligands in chemical equilibrium as a function of the length of the tether. These calculations are used in the research article Fibroblast Growth Factor 2 Dimer with Superagonist in vitro Activity Improves Granulation Tissue Formation During Wound Healing (Decker et al., in press [1]) to explain quantitatively how changes in polymeric linker length in the ligand dimers modifies the efficacy of these molecules relative to that of free ligands.

Identification and characterization of PPARα ligands in the hippocampus.

Science.gov (United States)

Roy, Avik; Kundu, Madhuchhanda; Jana, Malabendu; Mishra, Rama K; Yung, Yeni; Luan, Chi-Hao; Gonzalez, Frank J; Pahan, Kalipada

2016-12-01

Peroxisome proliferator-activated receptor-α (PPARα) regulates hepatic fatty acid catabolism and mediates the metabolic response to starvation. Recently we found that PPARα is constitutively activated in nuclei of hippocampal neurons and controls plasticity via direct transcriptional activation of CREB. Here we report the discovery of three endogenous PPARα ligands-3-hydroxy-(2,2)-dimethyl butyrate, hexadecanamide, and 9-octadecenamide-in mouse brain hippocampus. Mass spectrometric detection of these compounds in mouse hippocampal nuclear extracts, in silico interaction studies, time-resolved FRET analyses, and thermal shift assay results clearly indicated that these three compounds served as ligands of PPARα. Site-directed mutagenesis studies further revealed that PPARα Y464 and Y314 are involved in binding these hippocampal ligands. Moreover, these ligands activated PPARα and upregulated the synaptic function of hippocampal neurons. These results highlight the discovery of hippocampal ligands of PPARα capable of modulating synaptic functions.

Study of the production of the radiopharmaceutical 18F-FLT in automated system: contribution for process validation

International Nuclear Information System (INIS)

Zanette, Camila

2013-01-01

Radiopharmaceutical 18 F-FLT is a thymidine nucleoside analogue and a promising tumor proliferation marker for PET images. The synthesis of this radiopharmaceutical is not simple, and often has low yields. This radiopharmaceutical has already been studied for some years; however, there is no production, nor are there clinical studies in Brazil. The study of the production process and its compliance with the guidelines of Good Manufacturing Practices (ANVISA) are of extreme importance. This study aimed to investigate the synthesis of this radiopharmaceutical, evaluate methods of quality control that will be used in future production routines, perform cytotoxicity studies, biodistribution studies and PET imaging in animals, thereby contributing to the development and elaboration of the process validation protocol and to the establishment of analytical methods to be used during production routines. Initially, we studied the synthesis and production of 18 F-FLT, with the evaluation of three different temperatures of radiolabeling to check the behavior of the radiochemical yield and stability of the nal product. Studies of analytical methodology comprised the analysis of radionuclide identification, determination of chromatographic profiles, radiochemical purity, residual solvents, and pH. In vitro studies of internalization and cytotoxicity were also carried out. In in vivo studies, we evaluated the pharmacokinetics, biodistribution in healthy animals and in animals with tumor models, in addition to PET/CT images in animals with melanomas. The final product had high radiochemical purity and was stable for up to 10 hours after the synthesis, but got a relatively low radiochemical yield, as described in the literature. The tested analytical methods proved suitable for use in the quality control of 18 F-FLT. In in vitro studies, 18 F-FLT showed a significant percentage of binding to tumor cells, and the nonradiolabeled molecule was not considered toxic for these studied

In vivo imaging of therapy response to a novel Pan-HER antibody mixture using FDG and FLT positron emission tomography

DEFF Research Database (Denmark)

Nielsen, Carsten H; Jensen, Mette M; Kristensen, Lotte K

2015-01-01

response obtained by targeting HER family members individually or simultaneously using the novel monoclonal antibody (mAb) mixture Pan-HER. EXPERIMENTAL DESIGN AND RESULTS: Mice with subcutaneous BxPC-3 pancreatic adenocarcinomas were divided into five groups receiving vehicle or mAb mixtures directed...... to Pan-HER therapy. FDG and FLT PET/CT imaging should be considered as imaging biomarkers in clinical evaluation of the Pan-HER mAb mixture....

Maternal circulating levels of activin A, inhibin A, sFlt-1 and endoglin at parturition in normal pregnancy and pre-eclampsia.

Directory of Open Access Journals (Sweden)

Aparna Reddy

Full Text Available Maternal circulating levels of anti-angiogenic factors such as soluble fms-like tyrosine kinase-1 (sFlt-1, endoglin (sEng and placental proteins like activin A and inhibin A are increased before the onset of pre-eclampsia. There is evidence for oxidative stress in pre eclampsia. Recently it was shown that placental oxygen concentration is related to sFlt-1 and inhibin A. In addition it is reported that oxidative stress markers are increased in placental tissue delivered after labour. Therefore, the objective of this study is to investigate if these proteins are altered in maternal circulation of labouring pre-eclampsia and normal pregnancies.To assess the effects of labour, samples were taken from 10 normal pregnant (NP and 10 pre-eclamptic (PE women pre-labour, full dilation, placental delivery and 24 h. To assess the effects of placental delivery, plasma samples were taken from 10NP and 10PE women undergoing elective Caesarean section, pre-delivery, placental delivery and 10 min, 60 min and 24 h post delivery. SFlt-1 and sEng and activin A and inhibin A were measured using commercial and in house ELISA's respectively.The levels of sFlt-1 and sEng were significantly higher in PE compared to NP women in both groups. In labour, sFlt-1 levels increased significantly at full dilatation in PE women, before declining by 24 hr. However there was no significant rise in sEng levels in labour. Activin A and inhibin A levels declined rapidly with placental delivery in NP and PE pregnancies. There was a significant rise in activin A levels during labour in PE compared to pre labour, but inhibin levels did not increase.Labour in pre-eclamptic women increases the levels of sFlt-1 and activin A. This pilot data suggests that increase in the maternal levels of these factors in labour could predict and/or contribute to the maternal syndrome postpartum.

SKF 525-A and cytochrome P-450 ligands inhibit with high affinity the binding of [3H]dextromethorphan and σligands to guinea pig brain

International Nuclear Information System (INIS)

Klein, M.; Canoll, P.D.; Musacchio, J.M.

1991-01-01

The DM 1 /σ 1 site binds dextromethorphan (DM) and σ receptor ligands. The broad binding specificity of this site and its peculiar subcellular distribution prompted us to explore the possibility that this site is a member of the cytochrome P-450 superfamily of enzymes. We tested the effects of the liver microsomal monooxygenase inhibitor SKF 525-A (Proadifen), and other P-450 substrates on the binding of [ 3 H]dextromethorphan, [ 3 H]3-(3-Hydroxyphenyl)-N-(1-propyl)piperidine and (+)-[ 3 H]1,3-Di-o-tolyl-guanidine ([ 3 H]DTG) to the guinea pig brain. SKF 525-A, l-lobeline and GBR-12909 inhibited the binding of the three labeled ligands with nM affinity. Each drug has identical nM K i values for the high-affinity site labeled by the three ligands. This indicated that they displaced the labeled ligands from the common DM 1 σ 1 site. Debrisoquine and sparteine, prototypical substrates for liver debrisoquine 4-hydroxylase, displayed K i values of 9-13 and 3-4 μM respectively against the three labeled ligands. These results, the broad specificity of the DM 1 /σ 1 binding site, and its peculiar subcellular distribution, raises the possibility that this binding site is a member of the cytochrome P-450 superfamily of isozymes, rather than a neurotransmitter receptor

Photodegradation of luminescence in organic-ligand-capped Eu3+:LaF3 nano-particles

International Nuclear Information System (INIS)

King, Gavin G. G.; Taylor, Luke R.; Longdell, Jevon J.; Clarke, David J.; Quilty, J. W.

2014-01-01

The luminescence from europium doped lanthanum trifluoride (Eu 3+ :LaF 3 ) nano-crystals can be greatly enhanced by capping with β-diketonate organic ligands. Here, we report on photo-stability measurements for the case of nano-crystals capped with thenoyltrifluroacetone (TTA) and compared with those capped with an inactive ligand, oleic acid. With exposure to UV pump light, we observed significant decrease in fluorescence and change in emission spectrum of the TTA-capped nano-particles whilst the fluorescence lifetime remained approximately constant. After a dose of order 70 kJ cm −2 , the luminescence level was similar to that of oleic acid capped nano-crystals. We discuss possible mechanisms

[18F]FDG and [18F]FLT positron emission tomography imaging following treatment with belinostat in human ovary cancer xenografts in mice

DEFF Research Database (Denmark)

Jensen, Mette Munk; Erichsen, Kamille Dumong; Johnbeck, Camilla Bardram

2013-01-01

Belinostat is a histone deacetylase inhibitor with anti-tumor effect in several pre-clinical tumor models and clinical trials. The aim of the study was to evaluate changes in cell proliferation and glucose uptake by use of 3'-deoxy-3'-[(18)F]fluorothymidine ([18F]FLT) and 2-deoxy-2-[(18)F]fluoro-......]fluoro-D-glucose ([18F]FDG) positron emission tomography (PET) following treatment with belinostat in ovarian cancer in vivo models....

Enhancing gas adsorption and separation capacity through ligand functionalization of microporous metal-organic framework structures.

Science.gov (United States)

Zhao, Yonggang; Wu, Haohan; Emge, Thomas J; Gong, Qihan; Nijem, Nour; Chabal, Yves J; Kong, Lingzhu; Langreth, David C; Liu, Hui; Zeng, Heping; Li, Jing

2011-04-26

Hydroxyl- and amino- functionalized [Zn(BDC)(TED)(0.5)]·2DMF·0.2H(2)O leads to two new structures, [Zn(BDC-OH)(TED)(0.5)]·1.5DMF·0.3H(2)O and [Zn(BDC-NH(2))(TED)(0.5)]·xDMF·yH(2)O (BDC=terephthalic acid, TED=triethylenediamine, BDC-OH=2-hydroxylterephthalic acid, BDC-NH(2)=2-aminoterephthalic acid). Single-crystal X-ray diffraction and powder X-ray diffraction studies confirmed that the structures of both functionalized compounds are very similar to that of their parent structure. Compound [Zn(BDC)(TED)(0.5)]·2DMF·0.2H(2)O can be considered a 3D porous structure with three interlacing 1D channels, whereas both [Zn(BDC-OH)(TED)(0.5)]·1.5DMF·0.3H(2)O and [Zn(BDC-NH(2))(TED)(0.5)]·xDMF·yH(2)O contain only 1D open channels as a result of functionalization of the BDC ligand by the OH and NH(2) groups. A notable decrease in surface area and pore size is thus observed in both compounds. Consequently, [Zn(BDC)(TED)(0.5)]·2DMF·0.2H(2)O takes up the highest amount of H(2) at low temperatures. Interestingly, however, both [Zn(BDC-OH)(TED)(0.5)]·1.5DMF·0.3H(2)O and [Zn(BDC-NH(2))(TED)(0.5)]·xDMF·yH(2)O show significant enhancement in CO(2) uptake at room temperature, suggesting that the strong interactions between CO(2) and the functionalized ligands, indicating that surface chemistry, rather than porosity, plays a more important role in CO(2) adsorption. A comparison of single-component CO(2), CH(4), CO, N(2), and O(2) adsorption isotherms demonstrates that the adsorption selectivity of CO(2) over other small gases is considerably enhanced through functionalization of the frameworks. Infrared absorption spectroscopic measurements and theoretical calculations are also carried out to assess the effect of functional groups on CO(2) and H(2) adsorption potentials. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-assembling hydrogels crosslinked solely by receptor-ligand interactions: tunability, rationalization of physical properties, and 3D cell culture.

Science.gov (United States)

Thompson, Michael S; Tsurkan, Mikhail V; Chwalek, Karolina; Bornhauser, Martin; Schlierf, Michael; Werner, Carsten; Zhang, Yixin

2015-02-16

We report a novel, noncovalent hydrogel system crosslinked solely by receptor-ligand interactions between biotin and avidin. The simple hydrogel synthesis and functionalization together with the widespread use of biotinylated ligands in biosciences make this versatile system suitable for many applications. The gels possess a range of tunable physical properties, including stiffness, lifetime, and swelling. The erosion rates, unexpectedly fast compared to the kinetic parameters for biotin-avidin, are explored in terms of stretching tensions on the polymers, a concept well-known on the single-molecule level, but largely unexplored in supramolecular systems. As proof of utility, the gels were functionalized with different peptide sequences to control human mesenchymal stromal cell morphology in 3D culture. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

GALAHAD: 1. Pharmacophore identification by hypermolecular alignment of ligands in 3D

Science.gov (United States)

Richmond, Nicola J.; Abrams, Charlene A.; Wolohan, Philippa R. N.; Abrahamian, Edmond; Willett, Peter; Clark, Robert D.

2006-09-01

Alignment of multiple ligands based on shared pharmacophoric and pharmacosteric features is a long-recognized challenge in drug discovery and development. This is particularly true when the spatial overlap between structures is incomplete, in which case no good template molecule is likely to exist. Pair-wise rigid ligand alignment based on linear assignment (the LAMDA algorithm) has the potential to address this problem (Richmond et al. in J Mol Graph Model 23:199-209, 2004). Here we present the version of LAMDA embodied in the GALAHAD program, which carries out multi-way alignments by iterative construction of hypermolecules that retain the aggregate as well as the individual attributes of the ligands. We have also generalized the cost function from being purely atom-based to being one that operates on ionic, hydrogen bonding, hydrophobic and steric features. Finally, we have added the ability to generate useful partial-match 3D search queries from the hypermolecules obtained. By running frozen conformations through the GALAHAD program, one can utilize the extended version of LAMDA to generate pharmacophores and pharmacosteres that agree well with crystal structure alignments for a range of literature datasets, with minor adjustments of the default parameters generating even better models. Allowing for inclusion of partial match constraints in the queries yields pharmacophores that are consistently a superset of full-match pharmacophores identified in previous analyses, with the additional features representing points of potentially beneficial interaction with the target.

Inhibiting trophoblast PAR-1 overexpression suppresses sFlt-1-induced anti-angiogenesis and abnormal vascular remodeling: a possible therapeutic approach for preeclampsia.

Science.gov (United States)

Zhao, Yin; Zheng, YanFang; Liu, XiaoXia; Luo, QingQing; Wu, Di; Liu, XiaoPing; Zou, Li

2018-03-01

significantly suppressed sFlt-1 expression in trophoblasts. Soluble Flt-1 level in the supernatant was suppressed by PAR-1 inhibition plasmid transfection and increased by PAR-1 overexpression plasmids (46.93 ± 5.22 vs. 25.21 ± 4.18 vs. 67.84 ± 3.58 ng/ml, P overexpression may promote placental angiogenesis and vascular remodeling, potentially offering an alternative therapeutic approach for preeclampsia. This work was supported by grants from the National Natural Science Foundation of China (Grant Nos. 81100442 and 81771605 for Y.Z. and 81179584 for L.Z.) and the Hubei Province Health and Family Planning Scientific Research Project (Grant No. WJ2017 M093 for Y.Z.). The authors declare that there is no conflict of interest.

Real-Time Ligand Binding Pocket Database Search Using Local Surface Descriptors

Science.gov (United States)

Chikhi, Rayan; Sael, Lee; Kihara, Daisuke

2010-01-01

Due to the increasing number of structures of unknown function accumulated by ongoing structural genomics projects, there is an urgent need for computational methods for characterizing protein tertiary structures. As functions of many of these proteins are not easily predicted by conventional sequence database searches, a legitimate strategy is to utilize structure information in function characterization. Of a particular interest is prediction of ligand binding to a protein, as ligand molecule recognition is a major part of molecular function of proteins. Predicting whether a ligand molecule binds a protein is a complex problem due to the physical nature of protein-ligand interactions and the flexibility of both binding sites and ligand molecules. However, geometric and physicochemical complementarity is observed between the ligand and its binding site in many cases. Therefore, ligand molecules which bind to a local surface site in a protein can be predicted by finding similar local pockets of known binding ligands in the structure database. Here, we present two representations of ligand binding pockets and utilize them for ligand binding prediction by pocket shape comparison. These representations are based on mapping of surface properties of binding pockets, which are compactly described either by the two dimensional pseudo-Zernike moments or the 3D Zernike descriptors. These compact representations allow a fast real-time pocket searching against a database. Thorough benchmark study employing two different datasets show that our representations are competitive with the other existing methods. Limitations and potentials of the shape-based methods as well as possible improvements are discussed. PMID:20455259

Increased plasma levels of soluble vascular endothelial growth factor (VEGF) receptor 1 (sFlt-1) in women by moderate exercise and increased plasma levels of VEGF in overweight/obese women

Science.gov (United States)

Makey, Kristina L.; Patterson, Sharla G.; Robinson, James; Loftin, Mark; Waddell, Dwight E.; Miele, Lucio; Chinchar, Edmund; Huang, Min; Smith, Andrew D.; Weber, Mark; Gu, Jian-Wei

2012-01-01

The incidence of breast cancer is increasing worldwide, and this seems to be related to an increase in lifestyle risk factors, including physical inactivity, and overweight/obesity. We previously reported that exercise induced a circulating angiostatic phenotype characterized by increased sFlt-1 and endostatin and decreased unbound-VEGF in men. However, there is no data on women. The present study determines the following: 1) whether moderate exercise increased sFlt-1 and endostatin and decreased unbound-VEGF in the circulation of adult female volunteers; 2) whether overweight/obese women have a higher plasma level of unbound-VEGF than lean women. 72 African American and Caucasian adult women volunteers aged from 18–44 were enrolled into the exercise study. All the participants walked on a treadmill for 30 minutes at a moderate intensity (55–59% heart rate reserve), and oxygen consumption (VO2) was quantified by utilizing a metabolic cart. We had the blood samples before and immediately after exercise from 63 participants. ELISA assays (R&D Systems) showed that plasma levels of sFlt-1 were 67.8±3.7 pg/ml immediately after exercise (30 minutes), significantly higher than basal levels, 54.5±3.3 pg/ml, before exercise (P < 0.01; n=63). There was no significant difference in the % increase of sFlt-1 levels after exercise between African American and Caucasian (P=0.533) or between lean and overweight/obese women (P=0.892). There was no significant difference in plasma levels of unbound VEGF (35.28±5.47 vs. 35.23±4.96 pg/ml; P=0.99) or endostatin (111.12±5.48 vs. 115.45±7.15 ng/ml; P=0.63) before and after exercise. Basal plasma levels of unbound-VEGF in overweight/obese women were 52.26±9.6 pg/ml, significantly higher than basal levels of unbound-VEGF in lean women, 27.34±4.99 pg/ml (P < 0.05). The results support our hypothesis that exercise-induced plasma levels of sFlt-1 could be an important clinical biomarker to explore the mechanisms of exercise

Novel chalcone-based fluorescent human histamine H3 receptor ligands as pharmacological tools

Directory of Open Access Journals (Sweden)

Holger eStark

2012-03-01

Full Text Available Novel fluorescent chalcone-based ligands at human histamine H3 receptors (hH3R have been designed, synthesized and characterized. Compounds described are non-imidazole analogues of ciproxifan with a tetralone motif. Tetralones as chemical precursors and related fluorescent chalcones exhibit affinities at hH3R in the same concentration range like that of the reference antagonist ciproxifan (hH3R pKi value of 7.2. Fluorescence characterization of our novel ligands shows emission maxima about 570 nm for yellow fluorescent chalcones and ≥600 nm for the red fluorescent derivatives. Interferences to cellular autofluorescence could be excluded. All synthesized chalcone compounds could be taken to visualize hH3R proteins in stably transfected HEK-293 cells using confocal laser scanning fluorescence microscopy. These novel fluorescent ligands possess high potential to be used as pharmacological tools for hH3R visualization in different tissues.

Fully automated synthesis system of 3'-deoxy-3'-[18F]fluorothymidine

International Nuclear Information System (INIS)

Oh, Seung Jun; Mosdzianowski, Christoph; Chi, Dae Yoon; Kim, Jung Young; Kang, Se Hun; Ryu, Jin Sook; Yeo, Jeong Seok; Moon, Dae Hyuk

2004-01-01

We developed a new fully automated method for the synthesis of 3'-deoxy-3'-[ 18 F]fluorothymidine ([ 18 F]FLT), by modifying a commercial FDG synthesizer and its disposable fluid pathway. Optimal labeling condition was that 40 mg of precursor in acetonitrile (2 mL) was heated at 150 degree sign C for 100 sec, followed by heating at 85 degree sign C for 450 sec and hydrolysis with 1 N HCl at 105 degree sign C for 300 sec. Using 3.7 GBq of [ 18 F]F - as starting activity, [ 18 F]FLT was obtained with a yield of 50.5±5.2% (n=28, decay corrected) within 60.0±5.4 min including HPLC purification. With 37.0 GBq, we obtained 48.7±5.6% (n=10). The [ 18 F]FLT showed the good stability for 6 h. This new automated synthesis procedure combines high and reproducible yields with the benefits of a disposable cassette system

Periodic assessment of plasma sFlt-1 and PlGF concentrations and its association with placental morphometry in gestational hypertension (GH) - a prospective follow-up study.

Science.gov (United States)

Jeevaratnam, Kamalan; Nadarajah, Vishna Devi; Judson, John Paul; Nalliah, Sivalingam; Abdullah, Mohd Farouk

2010-09-28

Hypertensive disorders in pregnancy contributes to about 12% of maternal deaths in Malaysia and similarly worldwide. Early detection and adequate management are preventable strategies. Biochemical markers of abnormal angiogenesis would be more specific in early detection than routine blood pressure and proteinuria measurements. The aim of this study was to estimate maternal plasma PlGF and sFlt-1 levels in pregnant women with gestational hypertension at three intervals of pregnancy and correlate these biomarker levels with placental morphometry. Venous blood samples (antepartum, intrapartum and post partum periods) were drawn to estimate for sFlt-1 and PlGF levels while placental tissue samples were examined for placental morphometry. PlGF levels were lower in gestational hypertension (GH) compared to normotensive during antepartum and intrapartum period, whereas sFlt-1 levels were elevated in GH at antepartum, intrapartum and postpartum intervals during pregnancy. An inverse relationship between these two biomarkers was observed through correlation analysis. PlGF levels were inversely correlated with total villous surface area of the placental periphery (TCsa-C) and villous capillarization (VC-C) of the placental periphery. We established periodic values of for sFlt-1 and PlGF levels for the first time in an ethnically diverse Malaysian setting. We suggest the development of GH in women is related to defective capillarization. In demonstrating periodic changes, this study suggest the possibility of developing GH and other long term health complications as a result of prolonged exposure to sFlt-1. The correlation between PlGF levels and morphometric findings also support possible capillarization defect.

Ligand binding reduces SUMOylation of the peroxisome proliferator-activated receptor γ (PPARγ activation function 1 (AF1 domain.

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Rolf Diezko

Full Text Available Peroxisome proliferator-activated receptor gamma (PPARγ is a ligand-activated nuclear receptor regulating adipogenesis, glucose homeostasis and inflammatory responses. The activity of PPARγ is controlled by post-translational modifications including SUMOylation and phosphorylation that affects its biological and molecular functions. Several important aspects of PPARγ SUMOylation including SUMO isoform-specificity and the impact of ligand binding on SUMOylation remain unresolved or contradictory. Here, we present a comprehensive study of PPARγ1 SUMOylation. We show that PPARγ1 can be modified by SUMO1 and SUMO2. Mutational analyses revealed that SUMOylation occurs exclusively within the N-terminal activation function 1 (AF1 domain predominantly at lysines 33 and 77. Ligand binding to the C-terminal ligand-binding domain (LBD of PPARγ1 reduces SUMOylation of lysine 33 but not of lysine 77. SUMOylation of lysine 33 and lysine 77 represses basal and ligand-induced activation by PPARγ1. We further show that lysine 365 within the LBD is not a target for SUMOylation as suggested in a previous report, but it is essential for full LBD activity. Our results suggest that PPARγ ligands negatively affect SUMOylation by interdomain communication between the C-terminal LBD and the N-terminal AF1 domain. The ability of the LBD to regulate the AF1 domain may have important implications for the evaluation and mechanism of action of therapeutic ligands that bind PPARγ.

Origin of the Substitution Mechanism for the Binding of Organic Ligands on the Surface of CsPbBr3 Perovskite Nanocubes.

Science.gov (United States)

Ravi, Vikash Kumar; Santra, Pralay K; Joshi, Niharika; Chugh, Jeetender; Singh, Sachin Kumar; Rensmo, Håkan; Ghosh, Prasenjit; Nag, Angshuman

2017-10-19

Optoelectronic properties of CsPbBr 3 perovskite nanocubes (NCs) depend strongly on the interaction of the organic passivating molecules with the inorganic crystal. To understand this interaction, we employed a combination of synchrotron-based X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (NMR) spectroscopy, and first-principles density functional theory (DFT)-based calculations. Variable energy XPS elucidated the internal structure of the inorganic part in a layer-by-layer fashion, whereas NMR characterized the organic ligands. Our experimental results confirm that oleylammonium ions act as capping ligands by substituting Cs + ions from the surface of CsPbBr 3 NCs. DFT calculations shows that the substitution mechanism does not require much energy for surface reconstruction and, in contrast, stabilizes the nanocrystal by the formation of three hydrogen bonds between the -NH 3 + moiety of oleylammonium and surrounding Br - on the surface of NCs. This substitution mechanism and its origin are in stark contrast to the usual adsorption of organic ligands on the surface of typical NCs.

Outcome of the first wwPDB/CCDC/D3R Ligand Validation Workshop

Science.gov (United States)

Adams, Paul D.; Aertgeerts, Kathleen; Bauer, Cary; Bell, Jeffrey A.; Berman, Helen M.; Bhat, Talapady N.; Blaney, Jeff; Bolton, Evan; Bricogne, Gerard; Brown, David; Burley, Stephen K.; Case, David A.; Clark, Kirk L.; Darden, Tom; Emsley, Paul; Feher, Victoria A.; Feng, Zukang; Groom, Colin R.; Harris, Seth F.; Hendle, Jorg; Holder, Thomas; Joachimiak, Andrzej; Kleywegt, Gerard J.; Krojer, Tobias; Marcotrigiano, Joseph; Mark, Alan E.; Markley, John L.; Miller, Matthew; Minor, Wladek; Montelione, Gaetano T.; Murshudov, Garib; Nakagawa, Atsushi; Nakamura, Haruki; Nicholls, Anthony; Nicklaus, Marc; Nolte, Robert T.; Padyana, Anil K.; Peishoff, Catherine E.; Pieniazek, Susan; Read, Randy J.; Shao, Chenghua; Sheriff, Steven; Smart, Oliver; Soisson, Stephen; Spurlino, John; Stouch, Terry; Svobodova, Radka; Tempel, Wolfram; Terwilliger, Thomas C.; Tronrud, Dale; Velankar, Sameer; Ward, Suzanna; Warren, Gregory L.; Westbrook, John D.; Williams, Pamela; Yang, Huanwang; Young, Jasmine

2016-01-01

Summary Crystallographic studies of ligands bound to biological macromolecules (proteins and nucleic acids) represent an important source of information concerning drug-target interactions, providing atomic level insights into the physical chemistry of complex formation between macromolecules and ligands. Of the more than 115,000 entries extant in the Protein Data Bank archive, ~75% include at least one non-polymeric ligand. Ligand geometrical and stereochemical quality, the suitability of ligand models for in silico drug discovery/design, and the goodness-of-fit of ligand models to electron density maps vary widely across the archive. We describe the proceedings and conclusions from the first Worldwide Protein Data Bank/Cambridge Crystallographic Data Centre/Drug Design Data Resource (wwPDB/CCDC/D3R) Ligand Validation Workshop held at the Research Collaboratory for Structural Bioinformatics at Rutgers University on July 30–31, 2015. Experts in protein crystallography from academe and industry came together with non-profit and for-profit software providers for crystallography and with experts in computational chemistry and data archiving to discuss and make recommendations on best practices, as framed by a series of questions central to structural studies of macromolecule-ligand complexes. What data concerning bound ligands should be archived in the Protein Data Bank? How should the ligands be best represented? How should structural models of macromolecule-ligand complexes be validated? What supplementary information should accompany publications of structural studies of biological macromolecules? Consensus recommendations on best practices developed in response to each of these questions are provided, together with some details regarding implementation. Important issues addressed but not resolved at the workshop are also enumerated. PMID:27050687

Radioiodinated ligands for dopamine receptors

International Nuclear Information System (INIS)

Kung, H.F.

1994-01-01

The dopamine receptor system is important for normal brain function; it is also the apparent action site for various neuroleptic drugs for the treatment of schizophrenia and other metal disorders. In the past few years radioiodinated ligands for single photon emission tomography (SPECT) have been successfully developed and tested in humans: [ 123 I]TISCH for D1 dopamine receptors; [ 123 I]IBZM, epidepride, IBF and FIDA2, four iodobenzamide derivatives, for D2/D3 dopamine receptors. In addition, [ 123 I]β-CIT (RTI-55) and IPT, cocaine derivatives, for the dopamine reuptake site are potentially useful for diagnosis of loss of dopamine neurons. The first iodinated ligand, (R)trans-7-OH-PIPAT, for D3 dopamine receptors, was synthesized and characterized with cloned cell lines (Spodoptera frugiperda, Sf9) expressing the D2 and D3 dopamine receptors and with rat basal forebrain membrane preparations. Most of the known iodobenzamides displayed similar potency in binding to both D2 and D3 dopamine receptors expressed in the cell lines. Initial studies appear to suggest that by fine tuning the structures it may be possible to develop agents specific for D2 and D3 dopamine receptors. It is important to investigate D2/D3 selectivity for this series of potent ligands

3'-deoxy-3'-[18F]fluorothymidine PET Quantification of Bone Marrow Response to Radiation Dose

International Nuclear Information System (INIS)

McGuire, Sarah M.; Menda, Yusuf; Boles Ponto, Laura L.; Gross, Brandie; Buatti, John; Bayouth, John E.

2011-01-01

Purpose: The purpose of this study was to quantify the relationship of bone marrow response to radiation dose, using 3'-deoxy-3'-[ 18 F]fluorothymidine ([ 18 F]FLT)-labeled uptake quantified in positron-emission tomography (PET) scans. Methods and Materials: Pre- and post-Week 1 treatment [ 18 F]FLT PET images were registered to the CT images used to create the radiation treatment plan. Changes in [ 18 F]FLT uptake values were measured using profile data of standardized uptake values (SUVs) and doses along the vertebral bodies located at a field border where a range of radiation doses were present for 10 patients. Data from the profile measurements were grouped into 1 Gy dose bins from 1 to 9 Gy to compare SUV changes for all patients. Additionally, the maximum pretreatment, the post-Week 1 treatment, and the dose values located within the C6-T7 vertebrae that straddled the field edge were measured for all patients. Results: Both the profile and the individual vertebral data showed a strong correlation between SUV change and radiation dose. Relative differences in SUVs between bins >1 Gy and 18 F]FLT PET images for identifying active bone marrow and monitoring changes due to radiation dose. Additionally, the change in [ 18 F]FLT uptake observed in bone marrow for different weekly doses suggests potential dose thresholds for reducing bone marrow toxicity.

WE-H-207A-03: The Universality of the Lognormal Behavior of [F-18]FLT PET SUV Measurements

International Nuclear Information System (INIS)

Scarpelli, M; Eickhoff, J; Perlman, S; Jeraj, R

2016-01-01

Purpose: Log transforming [F-18]FDG PET standardized uptake values (SUVs) has been shown to lead to normal SUV distributions, which allows utilization of powerful parametric statistical models. This study identified the optimal transformation leading to normally distributed [F-18]FLT PET SUVs from solid tumors and offers an example of how normal distributions permits analysis of non-independent/correlated measurements. Methods: Forty patients with various metastatic diseases underwent up to six FLT PET/CT scans during treatment. Tumors were identified by nuclear medicine physician and manually segmented. Average uptake was extracted for each patient giving a global SUVmean (gSUVmean) for each scan. The Shapiro-Wilk test was used to test distribution normality. One parameter Box-Cox transformations were applied to each of the six gSUVmean distributions and the optimal transformation was found by selecting the parameter that maximized the Shapiro-Wilk test statistic. The relationship between gSUVmean and a serum biomarker (VEGF) collected at imaging timepoints was determined using a linear mixed effects model (LMEM), which accounted for correlated/non-independent measurements from the same individual. Results: Untransformed gSUVmean distributions were found to be significantly non-normal (p<0.05). The optimal transformation parameter had a value of 0.3 (95%CI: −0.4 to 1.6). Given the optimal parameter was close to zero (which corresponds to log transformation), the data were subsequently log transformed. All log transformed gSUVmean distributions were normally distributed (p>0.10 for all timepoints). Log transformed data were incorporated into the LMEM. VEGF serum levels significantly correlated with gSUVmean (p<0.001), revealing log-linear relationship between SUVs and underlying biology. Conclusion: Failure to account for correlated/non-independent measurements can lead to invalid conclusions and motivated transformation to normally distributed SUVs. The log

WE-H-207A-03: The Universality of the Lognormal Behavior of [F-18]FLT PET SUV Measurements

Energy Technology Data Exchange (ETDEWEB)

Scarpelli, M; Eickhoff, J; Perlman, S; Jeraj, R

2016-06-15

Purpose: Log transforming [F-18]FDG PET standardized uptake values (SUVs) has been shown to lead to normal SUV distributions, which allows utilization of powerful parametric statistical models. This study identified the optimal transformation leading to normally distributed [F-18]FLT PET SUVs from solid tumors and offers an example of how normal distributions permits analysis of non-independent/correlated measurements. Methods: Forty patients with various metastatic diseases underwent up to six FLT PET/CT scans during treatment. Tumors were identified by nuclear medicine physician and manually segmented. Average uptake was extracted for each patient giving a global SUVmean (gSUVmean) for each scan. The Shapiro-Wilk test was used to test distribution normality. One parameter Box-Cox transformations were applied to each of the six gSUVmean distributions and the optimal transformation was found by selecting the parameter that maximized the Shapiro-Wilk test statistic. The relationship between gSUVmean and a serum biomarker (VEGF) collected at imaging timepoints was determined using a linear mixed effects model (LMEM), which accounted for correlated/non-independent measurements from the same individual. Results: Untransformed gSUVmean distributions were found to be significantly non-normal (p<0.05). The optimal transformation parameter had a value of 0.3 (95%CI: −0.4 to 1.6). Given the optimal parameter was close to zero (which corresponds to log transformation), the data were subsequently log transformed. All log transformed gSUVmean distributions were normally distributed (p>0.10 for all timepoints). Log transformed data were incorporated into the LMEM. VEGF serum levels significantly correlated with gSUVmean (p<0.001), revealing log-linear relationship between SUVs and underlying biology. Conclusion: Failure to account for correlated/non-independent measurements can lead to invalid conclusions and motivated transformation to normally distributed SUVs. The log

Attenuation of vaccinia virus by the expression of human Flt3 ligand

Czech Academy of Sciences Publication Activity Database

Žurková, K.; Hainz, P.; Kryštofová, J.; Kutinová, L.; Šanda, Miloslav; Němečková, Š.

2010-01-01

Roč. 7, č. 1 (2010), 109/1-109/15 ISSN 1743-422X Institutional research plan: CEZ:AV0Z40550506 Keywords : vaccinia virus * antibodies * virulence Subject RIV: CE - Biochemistry Impact factor: 2.546, year: 2010

Noninvasive Evaluation of Cellular Proliferative Activity in Brain Neurogenic Regions in Rats under Depression and Treatment by Enhanced [18F]FLT-PET Imaging.

Science.gov (United States)

Tamura, Yasuhisa; Takahashi, Kayo; Takata, Kumi; Eguchi, Asami; Yamato, Masanori; Kume, Satoshi; Nakano, Masayuki; Watanabe, Yasuyoshi; Kataoka, Yosky

2016-08-03

Neural stem cells in two neurogenic regions, the subventricular zone and the subgranular zone (SGZ) of the hippocampal dentate gyrus, can divide and produce new neurons throughout life. Hippocampal neurogenesis is related to emotions, including depression/anxiety, and the therapeutic effects of antidepressants, as well as learning and memory. The establishment of in vivo imaging for proliferative activity of neural stem cells in the SGZ might be used to diagnose depression and to monitor the therapeutic efficacy of antidepressants. Positron emission tomography (PET) imaging with 3'-deoxy-3'-[(18)F]fluoro-l-thymidine ([(18)F]FLT) has been studied to allow visualization of proliferative activity in two neurogenic regions of adult mammals; however, the PET imaging has not been widely used because of lower accumulation of [(18)F]FLT, which does not allow quantitative assessment of the decline in cellular proliferative activity in the SGZ under the condition of depression. We report the establishment of an enhanced PET imaging method with [(18)F]FLT combined with probenecid, an inhibitor of drug transporters at the blood-brain barrier, which can allow the quantitative visualization of neurogenic activity in rats. Enhanced PET imaging allowed us to evaluate reduced cell proliferation in the SGZ of rats with corticosterone-induced depression, and further the recovery of proliferative activity in rats under treatment with antidepressants. This enhanced [(18)F]FLT-PET imaging technique with probenecid can be used to assess the dynamic alteration of neurogenic activity in the adult mammalian brain and may also provide a means for objective diagnosis of depression and monitoring of the therapeutic effect of antidepressant treatment. Adult hippocampal neurogenesis may play a role in major depression and antidepressant therapy. Establishment of in vivo imaging for hippocampal neurogenic activity may be useful to diagnose depression and monitor the therapeutic efficacy of

Differential TAM receptor-ligand-phospholipid interactions delimit differential TAM bioactivities.

Science.gov (United States)

Lew, Erin D; Oh, Jennifer; Burrola, Patrick G; Lax, Irit; Zagórska, Anna; Través, Paqui G; Schlessinger, Joseph; Lemke, Greg

2014-09-29

The TAM receptor tyrosine kinases Tyro3, Axl, and Mer regulate key features of cellular physiology, yet the differential activities of the TAM ligands Gas6 and Protein S are poorly understood. We have used biochemical and genetic analyses to delineate the rules for TAM receptor-ligand engagement and find that the TAMs segregate into two groups based on ligand specificity, regulation by phosphatidylserine, and function. Tyro3 and Mer are activated by both ligands but only Gas6 activates Axl. Optimal TAM signaling requires coincident TAM ligand engagement of both its receptor and the phospholipid phosphatidylserine (PtdSer): Gas6 lacking its PtdSer-binding 'Gla domain' is significantly weakened as a Tyro3/Mer agonist and is inert as an Axl agonist, even though it binds to Axl with wild-type affinity. In two settings of TAM-dependent homeostatic phagocytosis, Mer plays a predominant role while Axl is dispensable, and activation of Mer by Protein S is sufficient to drive phagocytosis.

S,O-Ligand-Promoted Palladium-Catalyzed C-H Functionalization Reactions of Nondirected Arenes

NARCIS (Netherlands)

Naksomboon, K.; Valderas, C.; Gomez-Martinez, M.; Alvarez-Casao, Y.; Fernández Ibáñez, M.A.

Pd(II)-catalyzed C-H functionalization of non directed arenes has been realized using an inexpensive and easily accessible type of bidentate S,O-ligand. The catalytic system shows high efficiency in the C-H olefination reaction of electron-rich and electron-poor arenes. This methodology is

Hydrogen Sulfide Attenuates sFlt1-Induced Hypertension and Renal Damage by Upregulating Vascular Endothelial Growth Factor

NARCIS (Netherlands)

Holwerda, Kim M.; Burke, Suzanne D.; Faas, Marijke M.; Zsengeller, Zsuzsanna; Stillman, Isaac E.; Kang, Peter M.; van Goor, Harry; McCurley, Amy; Jaffe, Iris Z.; Karumanchi, S. Ananth; Lely, A. Titia

Soluble fms-like tyrosine kinase 1 (sFlt1), a circulating antiangiogenic protein, is elevated in kidney diseases and contributes to the development of preeclampsia. Hydrogen sulfide is a vasorelaxant and proangiogenic gas with therapeutic potential in several diseases. Therefore, we evaluated the

Expression of the sFLT1 gene in cord blood cells is associated to maternal arsenic exposure and decreased birth weight

DEFF Research Database (Denmark)

Remy, Sylvie; Govarts, Eva; Bruckers, Liesbeth

2014-01-01

that birth weight decreased with 47 g (95% CI: 16-78 g) for an interquartile range increase of 0.99 μg/L arsenic. The model was adjusted for child's sex, maternal smoking during pregnancy, gestational age, and parity. Higher arsenic concentrations and reduced birth weight were positively associated...... with changes in expression of the sFLT1 (soluble fms-like tyrosine kinase-1) gene in cord blood cells in girls. The protein product of sFLT1 is a scavenger of vascular endothelial growth factor (VEGF) in the extracellular environment and plays a key role in the inhibition of placental angiogenesis. In terms...

Functional analysis of Ficolin-3 mediated complement activation

DEFF Research Database (Denmark)

Hein, Estrid; Honoré, Christian; Skjoedt, Mikkel-Ole

2010-01-01

Ficolin-3 mediated complement activation that could be applicable for research and clinical use. Bovine serum albumin (BSA) was acetylated (acBSA) and chosen as a solid phase ligand for Ficolins in microtiter wells. Binding of Ficolins on acBSA was evaluated, as was functional complement activation...... was applied to the samples that inhibited interference from the classical pathway due to the presence of anti-BSA antibodies in some sera. We describe a novel functional method for measuring complement activation mediated by Ficolin-3 in human serum up to the formation of TCC. The assay provides...

Identification of VDR Antagonists among Nuclear Receptor Ligands Using Virtual Screening

Directory of Open Access Journals (Sweden)

Kelly Teske

2014-04-01

Full Text Available Herein, we described the development of two virtual screens to identify new vitamin D receptor (VDR antagonists among nuclear receptor (NR ligands. Therefore, a database of 14330 nuclear receptor ligands and their NR affinities was assembled using the online available “Binding Database.” Two different virtual screens were carried out in conjunction with a reported VDR crystal structure applying a stringent and less stringent pharmacophore model to filter docked NR ligand conformations. The pharmacophore models were based on the spatial orientation of the hydroxyl functionalities of VDR's natural ligands 1,25(OH2D3 and 25(OH2D3. The first virtual screen identified 32 NR ligands with a calculated free energy of VDR binding of more than -6.0 kJ/mol. All but nordihydroguaiaretic acid (NDGA are VDR ligands, which inhibited the interaction between VDR and coactivator peptide SRC2-3 with an IC50 value of 15.8 μM. The second screen identified 162 NR ligands with a calculated free energy of VDR binding of more than -6.0 kJ/mol. More than half of these ligands were developed to bind VDR followed by ERα/β ligands (26%, TRα/β ligands (7%, and LxRα/β ligands (7%. The binding between VDR and ERα ligand H6036 as well as TRα/β ligand triiodothyronine and a homoserine analog thereof was confirmed by fluorescence polarization.

Dependence of stability of lanthanide(3) complexes with coloured ligands on the element nature

Energy Technology Data Exchange (ETDEWEB)

Poluehktov, N S; Meshkova, S B; Rusakova, N V [AN Ukrainskoj SSR, Odessa. Fiziko-Khimicheskij Inst.

1984-07-01

The change in the colour intensity of Ln(3) complexes with coloured ligands (methyl thymol blue, glycine cresol red, stilbazo, glycine thymol blue, methyl ortanyl S, ortanyl B, phthalexone S, semiphthalexone S, cresolphtalexone, sulfarsazen) in the natural series of lanthanoids is considered. A correlation equation is suggested that permits to describe the relative colour intensity (quenching molar coefficients, stability constants) of complexes in the series of lanthanide(3) ions versus the number of f-electrons, spin and orbital quantum numbers of the ground states. Using the ratio obtained it is possible to calculate the values of appropriate functions of complexes of elements for which such data are not available.

Periodic assessment of plasma sFlt-1 and PlGF concentrations and its association with placental morphometry in gestational hypertension (GH - a prospective follow-up study

Directory of Open Access Journals (Sweden)

Nalliah Sivalingam

2010-09-01

Full Text Available Abstract Background Hypertensive disorders in pregnancy contributes to about 12% of maternal deaths in Malaysia and similarly worldwide. Early detection and adequate management are preventable strategies. Biochemical markers of abnormal angiogenesis would be more specific in early detection than routine blood pressure and proteinuria measurements. The aim of this study was to estimate maternal plasma PlGF and sFlt-1 levels in pregnant women with gestational hypertension at three intervals of pregnancy and correlate these biomarker levels with placental morphometry. Methods Venous blood samples (antepartum, intrapartum and post partum periods were drawn to estimate for sFlt-1 and PlGF levels while placental tissue samples were examined for placental morphometry. Results PlGF levels were lower in gestational hypertension (GH compared to normotensive during antepartum and intrapartum period, whereas sFlt-1 levels were elevated in GH at antepartum, intrapartum and postpartum intervals during pregnancy. An inverse relationship between these two biomarkers was observed through correlation analysis. PlGF levels were inversely correlated with total villous surface area of the placental periphery (TCsa-C and villous capillarization (VC-C of the placental periphery. Conclusion We established periodic values of for sFlt-1 and PlGF levels for the first time in an ethnically diverse Malaysian setting. We suggest the development of GH in women is related to defective capillarization. In demonstrating periodic changes, this study suggest the possibility of developing GH and other long term health complications as a result of prolonged exposure to sFlt-1. The correlation between PlGF levels and morphometric findings also support possible capillarization defect.

Aromatic interactions impact ligand binding and function at serotonin 5-HT2C G protein-coupled receptors: receptor homology modelling, ligand docking, and molecular dynamics results validated by experimental studies

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Córdova-Sintjago, Tania; Villa, Nancy; Fang, Lijuan; Booth, Raymond G.

2014-02-01

The serotonin (5-hydroxytryptamine, 5-HT) 5-HT2 G protein-coupled receptor (GPCR) family consists of types 2A, 2B, and 2C that share ∼75% transmembrane (TM) sequence identity. Agonists for 5-HT2C receptors are under development for psychoses; whereas, at 5-HT2A receptors, antipsychotic effects are associated with antagonists - in fact, 5-HT2A agonists can cause hallucinations and 5-HT2B agonists cause cardiotoxicity. It is known that 5-HT2A TM6 residues W6.48, F6.51, and F6.52 impact ligand binding and function; however, ligand interactions with these residues at the 5-HT2C receptor have not been reported. To predict and validate molecular determinants for 5-HT2C-specific activation, results from receptor homology modelling, ligand docking, and molecular dynamics simulation studies were compared with experimental results for ligand binding and function at wild type and W6.48A, F6.51A, and F6.52A point-mutated 5-HT2C receptors.

[Supercomputer investigation of the protein-ligand system low-energy minima].

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Oferkin, I V; Sulimov, A V; Katkova, E V; Kutov, D K; Grigoriev, F V; Kondakova, O A; Sulimov, V B

2015-01-01

The accuracy of the protein-ligand binding energy calculations and ligand positioning is strongly influenced by the choice of the docking target function. This work demonstrates the evaluation of the five different target functions used in docking: functions based on MMFF94 force field and functions based on PM7 quantum-chemical method accounting or without accounting the implicit solvent model (PCM, COSMO or SGB). For these purposes the ligand positions corresponding to the minima of the target function and the experimentally known ligand positions in the protein active site (crystal ligand positions) were compared. Each function was examined on the same test-set of 16 protein-ligand complexes. The new parallelized docking program FLM based on Monte Carlo search algorithm was developed to perform the comprehensive low-energy minima search and to calculate the protein-ligand binding energy. This study demonstrates that the docking target function based on the MMFF94 force field can be used to detect the crystal or near crystal positions of the ligand by the finding the low-energy local minima spectrum of the target function. The importance of solvent accounting in the docking process for the accurate ligand positioning is also shown. The accuracy of the ligand positioning as well as the correlation between the calculated and experimentally determined protein-ligand binding energies are improved when the MMFF94 force field is substituted by the new PM7 method with implicit solvent accounting.

Increased plasma levels of soluble vascular endothelial growth factor receptor 1 (sFlt-1) in women by moderate exercise and increased plasma levels of vascular endothelial growth factor in overweight/obese women.

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Makey, Kristina L; Patterson, Sharla G; Robinson, James; Loftin, Mark; Waddell, Dwight E; Miele, Lucio; Chinchar, Edmund; Huang, Min; Smith, Andrew D; Weber, Mark; Gu, Jian-Wei

2013-01-01

The incidence of breast cancer is increasing worldwide, and this seems to be related to an increase in lifestyle risk factors, including physical inactivity and overweight/obesity. We have reported previously that exercise induced a circulating angiostatic phenotype characterized by increased soluble fms-like tyrosine kinase-1 (sFlt-1) and endostatin and decreased unbound vascular endothelial growth factor (VEGF) in men. However, there are no data on women. The present study determines the following: (a) whether moderate exercise increased sFlt-1 and endostatin and decreased unbound VEGF in the circulation of adult female volunteers and (b) whether overweight/obese women have a higher plasma level of unbound VEGF than lean women. A total of 72 African American and White adult women volunteers ranging in age from 18 to 44 years were enrolled in the exercise study. All the participants walked on a treadmill for 30 min at a moderate intensity (55-59% heart rate reserve), and oxygen consumption (VO(2)) was quantified utilizing a metabolic cart. We obtained blood samples before and immediately after exercise from 63 participants. ELISA assays showed that the plasma levels of sFlt-1 were 67.8±3.7 pg/ml immediately after exercise (30 min), significantly higher than the basal levels, 54.5±3.3 pg/ml, before exercise (P<0.01; n=63). There was no significant difference in the % increase in the sFlt-1 levels after exercise between African American and White (P=0.533) women or between lean and overweight/obese women (P=0.892). There was no significant difference in the plasma levels of unbound VEGF (35.28±5.47 vs. 35.23±4.96 pg/ml; P=0.99) or endostatin (111.12±5.48 vs. 115.45±7.15 ng/ml; P=0.63) before and after exercise. The basal plasma levels of unbound VEGF in overweight/obese women were 52.26±9.6 pg/ml, significantly higher than the basal levels of unbound VEGF in lean women, 27.34±4.99 pg/ml (P<0.05). The results support our hypothesis that exercise

Computational fragment-based screening using RosettaLigand: the SAMPL3 challenge

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Kumar, Ashutosh; Zhang, Kam Y. J.

2012-05-01

SAMPL3 fragment based virtual screening challenge provides a valuable opportunity for researchers to test their programs, methods and screening protocols in a blind testing environment. We participated in SAMPL3 challenge and evaluated our virtual fragment screening protocol, which involves RosettaLigand as the core component by screening a 500 fragments Maybridge library against bovine pancreatic trypsin. Our study reaffirmed that the real test for any virtual screening approach would be in a blind testing environment. The analyses presented in this paper also showed that virtual screening performance can be improved, if a set of known active compounds is available and parameters and methods that yield better enrichment are selected. Our study also highlighted that to achieve accurate orientation and conformation of ligands within a binding site, selecting an appropriate method to calculate partial charges is important. Another finding is that using multiple receptor ensembles in docking does not always yield better enrichment than individual receptors. On the basis of our results and retrospective analyses from SAMPL3 fragment screening challenge we anticipate that chances of success in a fragment screening process could be increased significantly with careful selection of receptor structures, protein flexibility, sufficient conformational sampling within binding pocket and accurate assignment of ligand and protein partial charges.

Expression and function of Delta-like ligand 4 in a rat model of retinopathy of prematurity

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Shaoyang Shi; Xun Li; You Li; Cunwen Pei; Hongwei Yang; Xiaolong Chen

2013-01-01

The Delta-like ligand 4/Notch signaling pathway was shown to participate in the process of retinal development and angiogenesis. However, the function of the Delta-like ligand 4/Notch signaling pathway in retinopathy of prematurity requires further study. Retinopathy of prematurity was induced in 5-day-old Sprague-Dawley rats exposed to hyperoxia for 7 days, and then returned to room air. Reverse transcription-PCR and western blot revealed that Delta-like ligand 4 levels decreased at postnatal day 12 and increased at postnatal day 17 in retinopathy of prematurity rats. Flat-mounted adenosine diphosphatase stained retina and hematoxylin-eosin stained retinal tissue slices showed that the clock hour scores and the nuclei counts in retinopathy of prematurity rats were significantly different compared to normal control rats. After retinopathy of prematurity rats were intravitreally injected with Delta-like ligand 4 monoclonal antibody to inhibit the Delta-like ligand 4/Notch signaling pathway, there was a significant increase in the severity of retinal neovascularization (clock hours) in the intravitreally injected eyes. The nuclei count was highly correlated with the clock hour score. These results suggest that Delta-like ligand 4/Notch signaling plays an essential role in the process of physiological and pathological angiogenesis in the retina.

Synthesis and Optical Properties of Thiol Functionalized CdSe/ZnS (Core/Shell Quantum Dots by Ligand Exchange

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Huaping Zhu

2014-01-01

Full Text Available The colloidal photoluminescent quantum dots (QDs of CdSe (core and CdSe/ZnS (core/shell were synthesized at different temperatures with different growth periods. Optical properties (i.e., UV/Vis spectra and photoluminescent emission spectra of the resulting QDs were investigated. The shell-protected CdSe/ZnS QDs exhibited higher photoluminescent (PL efficiency and stability than their corresponding CdSe core QDs. Ligand exchange with various thiol molecules was performed to replace the initial surface passivation ligands, that is, trioctylphosphine oxide (TOPO and trioctylphosphine (TOP, and the optical properties of the surface-modified QDs were studied. The thiol ligand molecules in this study included 1,4-benzenedimethanethiol, 1,16-hexadecanedithiol, 1,11-undecanedithiol, biphenyl-4,4′-dithiol, 11-mercapto-1-undecanol, and 1,8-octanedithiol. After the thiol functionalization, the CdSe/ZnS QDs exhibited significantly enhanced PL efficiency and storage stability. Besides surface passivation effect, such enhanced performance of thiol-functionalized QDs could be due to cross-linked assembly formation of dimer/trimer clusters, in which QDs are linked by dithiol molecules. Furthermore, effects of ligand concentration, type of ligand, and heating on the thiol stabilization of QDs were also discussed.

Pemetrexed induced thymidylate synthase inhibition in non-small cell lung cancer patients: a pilot study with 3'-deoxy-3'-[¹⁸F]fluorothymidine positron emission tomography.

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Virginie Frings

Full Text Available OBJECTIVES: Pemetrexed is a thymidylate synthase (TS inhibitor and is effective in non-small cell lung cancer (NSCLC. 3'-deoxy-3'-[¹⁸F]fluorothymidine (¹⁸F-FLT, a proliferation marker, could potentially identify tumor specific TS-inhibition. The aim of this study was to investigate the effect of pemetrexed-induced TS-inhibition on ¹⁸F-FLT uptake 4 hours after pemetrexed administration in metastatic NSCLC patients. METHODS: Fourteen NSCLC patients underwent dynamic ¹⁸F-FLT positron emission tomography (PET scans at baseline and 4 hours after the first dose of pemetrexed. Volumes of interest were defined with a 41%, 50% and 70% threshold of the maximum pixel. Kinetic analysis and simplified measures were performed. At one, two, four and six hours after pemetrexed, plasma deoxyuridine was measured as systemic indicator of TS-inhibition. Tumor response measured with response evaluation criteria in solid tumors (RECIST, time to progression (TTP and overall survival (OS were determined. RESULTS: Eleven patients had evaluable ¹⁸F-FLT PET scans at baseline and 4 hours after pemetrexed. Two patients had increased ¹⁸F-FLT uptake of 35% and 31% after pemetrexed, whereas two other patients had decreased uptake of 31%. In the remaining seven patients ¹⁸F-FLT uptake did not change beyond test-retest borders. In all patients deoxyuridine levels raised after administration of pemetrexed, implicating pemetrexed-induced TS-inhibition. ¹⁸F-FLT uptake in bone marrow was significantly increased 4 hours after pemetrexed administration. Six weeks after the start of treatment 5 patients had partial response, 4 stable disease and 2 progressive disease. Median TTP was 4.2 months (range 3.0-7.4 months; median OS was 13.0 months (range 5.1-30.8 months. Changes in ¹⁸F-FLT uptake were not predictive for tumor response, TTP or OS. CONCLUSIONS: Measuring TS-inhibition in a clinical setting 4 hours after pemetrexed revealed a non-systematic change in

Ligand fishing from Dioscorea nipponica extract using human serum albumin functionalized magnetic nanoparticles.

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Qinga, Lin-Sen; Xue, Ying; Zheng, Yi; Xiong, Jing; Liao, Xun; Ding, Li-Sheng; Li, Bo-Gang; Liu, Yi-Ming

2010-07-09

Dioscorea nipponica and the preparations made from it have been used for long to prevent and treat coronary heart disease in traditional Chinese medicine. A group of steroidal saponins present in the plant are believed to be the active ingredients. It has been a challenge to study the individual saponins separately due to the similarities in their chemical and physical properties. In this work, human serum albumin (HSA) functionalized magnetic nanoparticles (MNPs) were used to isolate and identify saponin ligands that bind to HSA from D. nipponica extract. Electrospray ionization mass spectrometry (ESI-MS) was used for compound identification and semi-quantification. Three saponins, i.e. dioscin, gracillin, and pseudo-protodioscin showed affinity to HSA-MNPs and thus isolated effectively from the extract. The other two saponins detected in the extract (i.e. protodioscin and 26-O-β-D-glucopyranosyl-3β,20α,26-triol-25(R)-Δ(5,22)-dienofurostan-3-O-α-L-rhamnopyranosyl (1→2)-[α-L-rhamnopyranosyl (1→4)]-β-D-glucopyranoside) exhibited no affinity at all. Among the three saponins fished out, dioscin bound to HSA much stronger than gracillin and pseudo-protodioscin did. The results indicated that affinity interaction between HSA immobilized on MNPs and small molecule compounds were highly dependent on chemical structures and, potentially, medicinal usefulness. The present work demonstrates a facile and effective way to isolate and identify ligands of receptors from medicinal plants.

Targeting Selectins and Their Ligands in Cancer

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Alessandro eNatoni

2016-04-01

Full Text Available Aberrant glycosylation is a hallmark of cancer cells with increased evidence pointing to a role in tumor progression. In particular, aberrant sialylation of glycoproteins and glycolipids have been linked to increased immune cell evasion, drug evasion, drug resistance, tumor invasiveness, and vascular dissemination leading to metastases. Hypersialylation of cancer cells is largely the result of overexpression of sialyltransferases. Humans differentially express twenty different sialyltransferases in a tissue-specific manner, each of which catalyze the attachment of sialic acids via different glycosidic linkages (2-3; 2-6 or 2-8 to the underlying glycan chain. One important mechanism whereby overexpression of sialyltransferases contributes to an enhanced metastatic phenotype is via the generation of selectin ligands. Selectin ligand function requires the expression of sialyl-Lewis X and its structural-isomer sialyl-Lewis A, which are synthesized by the combined action of alpha 1-3-fucosyltransferases, 2-3-sialyltransferases, 1-4-galactosyltranferases, and N-acetyl--glucosaminyltransferases. The α2-3-sialyltransferases ST3Gal4 and ST3Gal6 are critical to the generation of functional E- and P-selectin ligands and overexpression of these sialyltransferases have been linked to increased risk of metastatic disease in solid tumors and poor outcome in multiple myeloma. Thus, targeting selectins and their ligands as well as the enzymes involved in their generation, in particular sialyltransferases, could be beneficial to many cancer patients. Potential strategies include sialyltransferase inhibition and the use of selectin antagonists, such as glycomimetic drugs and antibodies. Here, we review ongoing efforts to optimize the potency and selectivity of sialyltransferase inhibitors, including the potential for targeted delivery approaches, as well as evaluate the potential utility of selectin inhibitors, which are now in early clinical

Two novel mixed-ligand complexes containing organosulfonate ligands.

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Li, Mingtian; Huang, Jun; Zhou, Xuan; Fang, Hua; Ding, Liyun

2008-07-01

The structures reported herein, viz. bis(4-aminonaphthalene-1-sulfonato-kappaO)bis(4,5-diazafluoren-9-one-kappa(2)N,N')copper(II), [Cu(C(10)H(8)NO(3)S)(2)(C(11)H(6)N(2)O)(2)], (I), and poly[[[diaquacadmium(II)]-bis(mu-4-aminonaphthalene-1-sulfonato)-kappa(2)O:N;kappa(2)N:O] dihydrate], {[Cd(C(10)H(8)NO(3)S)(2)(H(2)O)(2)].2H(2)O}(n), (II), are rare examples of sulfonate-containing complexes where the anion does not fulfill a passive charge-balancing role, but takes an active part in coordination as a monodentate and/or bridging ligand. Monomeric complex (I) possesses a crystallographic inversion center at the Cu(II) atom, and the asymmetric unit contains one-half of a Cu atom, one complete 4-aminonaphthalene-1-sulfonate (ans) ligand and one 4,5-diazafluoren-9-one (DAFO) ligand. The Cu(II) atom has an elongated distorted octahedral coordination geometry formed by two O atoms from two monodentate ans ligands and by four N atoms from two DAFO molecules. Complex (II) is polymeric and its crystal structure is built up by one-dimensional chains and solvent water molecules. Here also the cation (a Cd(II) atom) lies on a crystallographic inversion center and adopts a slightly distorted octahedral geometry. Each ans anion serves as a bridging ligand linking two Cd(II) atoms into one-dimensional infinite chains along the [010] direction, with each Cd(II) center coordinated by four ans ligands via O and N atoms and by two aqua ligands. In both structures, there are significant pi-pi stacking interactions between adjacent ligands and hydrogen bonds contribute to the formation of two- and three-dimensional networks.

Strong metal-metal coupling in mixed-valent intermediates [Cl(L)Ru(mu-tppz)Ru(L)Cl](+), L = beta-diketonato ligands, tppz=2,3,5,6-tetrakis(2-pyridyl)pyrazine

Czech Academy of Sciences Publication Activity Database

Kundu, T.; Schweinfurth, D.; Sarkar, B.; Mondal, T. K.; Fiedler, Jan; Mobin, S. M.; Puranik, V. G.; Kaim, W.; Lahiri, G. K.

2012-01-01

Roč. 41, č. 43 (2012), s. 13429-13440 ISSN 1477-9226 R&D Projects: GA AV ČR IAA400400802 Institutional support: RVO:61388955 Keywords : TRIDENTATE BRIDGING LIGAND * DENSITY-FUNCTIONAL THEORY * HYDRAZONE-BASED LIGAND S Subject RIV: CG - Electrochemistry Impact factor: 3.806, year: 2012

Pentameric ligand-gated ion channels exhibit distinct transmembrane domain archetypes for folding/expression and function.

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Therien, J P Daniel; Baenziger, John E

2017-03-27

Although transmembrane helix-helix interactions must be strong enough to drive folding, they must still permit the inter-helix movements associated with conformational change. Interactions between the outermost M4 and adjacent M1 and M3 α-helices of pentameric ligand-gated ion channels have been implicated in folding and function. Here, we evaluate the role of different physical interactions at this interface in the function of two prokaryotic homologs, GLIC and ELIC. Strikingly, disruption of most interactions in GLIC lead to either a reduction or a complete loss of expression and/or function, while analogous disruptions in ELIC often lead to gains in function. Structural comparisons suggest that GLIC and ELIC represent distinct transmembrane domain archetypes. One archetype, exemplified by GLIC, the glycine and GABA receptors and the glutamate activated chloride channel, has extensive aromatic contacts that govern M4-M1/M3 interactions and that are essential for expression and function. The other archetype, exemplified by ELIC and both the nicotinic acetylcholine and serotonin receptors, has relatively few aromatic contacts that are detrimental to function. These archetypes likely have evolved different mechanisms to balance the need for strong M4 "binding" to M1/M3 to promote folding/expression, and the need for weaker interactions that allow for greater conformational flexibility.

ICOS:ICOS-ligand interaction is required for type 2 innate lymphoid cell function, homeostasis, and induction of airway hyperreactivity.

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Maazi, Hadi; Patel, Nisheel; Sankaranarayanan, Ishwarya; Suzuki, Yuzo; Rigas, Diamanda; Soroosh, Pejman; Freeman, Gordon J; Sharpe, Arlene H; Akbari, Omid

2015-03-17

Allergic asthma is caused by Th2-cell-type cytokines in response to allergen exposure. Type 2 innate lymphoid cells (ILC2s) are a newly identified subset of immune cells that, along with Th2 cells, contribute to the pathogenesis of asthma by producing copious amounts of IL-5 and IL-13, which cause eosinophilia and airway hyperreactivity (AHR), a cardinal feature of asthma. ILC2s express ICOS, a T cell costimulatory molecule with a currently unknown function. Here we showed that a lack of ICOS on murine ILC2s and blocking the ICOS:ICOS-ligand interaction in human ILC2s reduced AHR and lung inflammation. ILC2s expressed both ICOS and ICOS-ligand, and the ICOS:ICOS-ligand interaction promoted cytokine production and survival in ILC2s through STAT5 signaling. Thus, ICOS:ICOS-ligand signaling pathway is critically involved in ILC2 function and homeostasis. Copyright © 2015 Elsevier Inc. All rights reserved.

Context-Dependent Functional Divergence of the Notch Ligands DLL1 and DLL4 In Vivo.

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Kristina Preuße

2015-06-01

Full Text Available Notch signalling is a fundamental pathway that shapes the developing embryo and sustains adult tissues by direct communication between ligand and receptor molecules on adjacent cells. Among the ligands are two Delta paralogues, DLL1 and DLL4, that are conserved in mammals and share a similar structure and sequence. They activate the Notch receptor partly in overlapping expression domains where they fulfil redundant functions in some processes (e.g. maintenance of the crypt cell progenitor pool. In other processes, however, they appear to act differently (e.g. maintenance of foetal arterial identity raising the questions of how similar DLL1 and DLL4 really are and which mechanism causes the apparent context-dependent divergence. By analysing mice that conditionally overexpress DLL1 or DLL4 from the same genomic locus (Hprt and mice that express DLL4 instead of DLL1 from the endogenous Dll1 locus (Dll1Dll4ki, we found functional differences that are tissue-specific: while DLL1 and DLL4 act redundantly during the maintenance of retinal progenitors, their function varies in the presomitic mesoderm (PSM where somites form in a Notch-dependent process. In the anterior PSM, every cell expresses both Notch receptors and ligands, and DLL1 is the only activator of Notch while DLL4 is not endogenously expressed. Transgenic DLL4 cannot replace DLL1 during somitogenesis and in heterozygous Dll1Dll4ki/+ mice, the Dll1Dll4ki allele causes a dominant segmentation phenotype. Testing several aspects of the complex Notch signalling system in vitro, we found that both ligands have a similar trans-activation potential but that only DLL4 is an efficient cis-inhibitor of Notch signalling, causing a reduced net activation of Notch. These differential cis-inhibitory properties are likely to contribute to the functional divergence of DLL1 and DLL4.

Stable curcumin-loaded polymeric micellar formulation for enhancing cellular uptake and cytotoxicity to FLT3 overexpressing EoL-1 leukemic cells.

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Tima, Singkome; Anuchapreeda, Songyot; Ampasavate, Chadarat; Berkland, Cory; Okonogi, Siriporn

2017-05-01

The present study aims to develop a stable polymeric micellar formulation of curcumin (CM) with improved solubility and stability, and that is suitable for clinical applications in leukemia patients. CM-loaded polymeric micelles (CM-micelles) were prepared using poloxamers. The chemical structure of the polymers influenced micellar properties. The best formulation of CM-micelles, namely CM-P407, was obtained from poloxamer 407 at drug to polymer ratio of 1:30 and rehydrated with phosphate buffer solution pH 7.4. CM-P407 exhibited the smallest size of 30.3±1.3nm and highest entrapment efficiency of 88.4±4.1%. When stored at -80°C for 60days, CM-P407 retained high protection of CM and had no significant size change. In comparison with CM solution in dimethyl sulfoxide (CM-DMSO), CM kinetic degradation in both formulations followed a pseudo-first-order reaction, but the half-life of CM in CM-P407 was approx. 200 times longer than in CM-DMSO. Regarding the activity against FLT3 overexpressing EoL-1 leukemic cells, CM-P407 showed higher cytotoxicity than CM-DMSO. Moreover, intracellular uptake to leukemic cells of CM-P407 was 2-3 times greater than that of CM-DMSO. These promising results for CM-P407 will be further investigated in rodents and in clinical studies for leukemia treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Recent insights into the implications of metabolism in plasmacytoid dendritic cell innate functions: Potential ways to control these functions [version 1; referees: 1 approved, 2 approved with reservations

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Philippe Saas

2017-04-01

Full Text Available There are more and more data concerning the role of cellular metabolism in innate immune cells, such as macrophages or conventional dendritic cells. However, few data are available currently concerning plasmacytoid dendritic cells (PDC, another type of innate immune cells. These cells are the main type I interferon (IFN producing cells, but they also secrete other pro-inflammatory cytokines (e.g., tumor necrosis factor or interleukin [IL]-6 or immunomodulatory factors (e.g., IL-10 or transforming growth factor-β. Through these functions, PDC participate in antimicrobial responses or maintenance of immune tolerance, and have been implicated in the pathophysiology of several autoimmune diseases. Recent data support the idea that the glycolytic pathway (or glycolysis, as well as lipid metabolism (including both cholesterol and fatty acid metabolism may impact some innate immune functions of PDC or may be involved in these functions after Toll-like receptor (TLR 7/9 triggering. Some differences may be related to the origin of PDC (human versus mouse PDC or blood-sorted versus FLT3 ligand stimulated-bone marrow-sorted PDC. The kinetics of glycolysis may differ between human and murine PDC. In mouse PDC, metabolism changes promoted by TLR7/9 activation may depend on an autocrine/paracrine loop, implicating type I IFN and its receptor IFNAR, explaining a delayed glycolysis. Moreover, PDC functions can be modulated by the metabolism of cholesterol and fatty acids. This may occur via the production of lipid ligands that activate nuclear receptors (e.g., liver X receptor [LXR] in PDC or through limiting intracellular cholesterol pool size (by statins or LXR agonists in these cells. Finally, lipid-activated nuclear receptors (i.e., LXR or peroxisome proliferator activated receptor may also directly interact with pro-inflammatory transcription factors, such as NF-κB. Here, we discuss how glycolysis and lipid metabolism may modulate PDC functions and how

An -OH group functionalized MOF for ratiometric Fe3+ sensing

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Xu, Hui; Dong, Yingying; Wu, Yuhang; Ren, Wenjing; Zhao, Tao; Wang, Shunli; Gao, Junkuo

2018-02-01

Iron is one of the most important elements in the biochemical processes in all living system, both deficiency or excess of iron will lead to metabolism disorder diseases. However, Fe3+ is one of the most efficient fluorescence quenchers among the transition-metal ions because of its paramagnetic nature. The realization of Fe3+ ratiometric and self-calibrated fluorescent sensor is highly-challenging. We synthesized a novel luminescent -OH functionalized EuOHBDC (Eu2(OH-BDC)3, OH-BDC=2-hydroxyterephthalic acid) by hydrothermal reaction and in situ ligand synthesis, and used it as a rare ratiomatric luminescent sensor for Fe3+ ions. The -OH functional group facilitates both electron transfer and binding interaction between EuOHBDC and Fe3+, which lead to luminescent quenching of ligand-based emission while enhancement of a new peak emission, and thus enables ratiometric detection of Fe3+. The relative fluorescent intensity ratio (I375/I427) increased linearly with increasing Fe3+ concentration in the 10-50 μM range with 1.17 μM (65 ppb) detection limit. The EuOHBDC also shows excellent selectivity towards different metal ions, particularly can discriminate Fe3+ and Fe2+ through different luminescent responses. This result clearly demonstrates the superiority of -OH functionalized MOF for Fe3+ detection, which can contribute to develop high performance luminescent probe for detection of metal ions in environmental and biomedical applications.

Adducts of nitrogenous ligands with rhodium(II) tetracarboxylates and tetraformamidinate: NMR spectroscopy and density functional theory calculations.

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Cmoch, Piotr; Głaszczka, Rafał; Jaźwiński, Jarosław; Kamieński, Bohdan; Senkara, Elżbieta

2014-03-01

Complexation of tetrakis(μ2-N,N'-diphenylformamidinato-N,N')-di-rhodium(II) with ligands containing nitrile, isonitrile, amine, hydroxyl, sulfhydryl, isocyanate, and isothiocyanate functional groups has been studied in liquid and solid phases using (1)H, (13)C and (15)N NMR, (13)C and (15)N cross polarisation-magic angle spinning NMR, and absorption spectroscopy in the visible range. The complexation was monitored using various NMR physicochemical parameters, such as chemical shifts, longitudinal relaxation times T1 , and NOE enhancements. Rhodium(II) tetraformamidinate selectively bonded only unbranched amine (propan-1-amine), pentanenitrile, and (1-isocyanoethyl)benzene. No complexation occurred in the case of ligands having hydroxyl, sulfhydryl, isocyanate, and isothiocyanate functional groups, and more expanded amine molecules such as butan-2-amine and 1-azabicyclo[2.2.2]octane. Such features were opposite to those observed in rhodium(II) tetracarboxylates, forming adducts with all kind of ligands. Special attention was focused on the analysis of Δδ parameters, defined as a chemical shift difference between signal in adduct and corresponding signal in free ligand. In the case of (1)H NMR, Δδ values were either negative in adducts of rhodium(II) tetraformamidinate or positive in adducts of rhodium(II) tetracarboxylates. Experimental findings were supported by density functional theory molecular modelling and gauge independent atomic orbitals chemical shift calculations. The calculation of chemical shifts combined with scaling procedure allowed to reproduce qualitatively Δδ parameters. Copyright © 2013 John Wiley & Sons, Ltd.

Clinical value of 18F-FDG and 18F-FLT PET /CT for the detection of primary and regional lymph node metastasis of gastric cancer

Institute of Scientific and Technical Information of China (English)

杨洋

2014-01-01

Objective To evaluate the value of18F-FDG and18F-FLT PET/CT for the detection of primary and regional lymph node metastasis of gastric cancer.Methods Thirty-seven patients with gastric cancer underwent preoperative18F-FLT and18F-FDG PET/CT within one week from March 2011 to April 2013.Postoperative histopathology confirmation was obtained in all patients.The PET/CT images were assessed visually and semi-quantitatively.Two-sample t andχ2tests were analyzed using SPSS overall diagnostic

Electrical and Plasmonic Properties of Ligand-Free Sn(4+) -Doped In2 O3 (ITO) Nanocrystals.

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Jagadeeswararao, Metikoti; Pal, Somnath; Nag, Angshuman; Sarma, D D

2016-03-03

Sn(4+) -doped In2 O3 (ITO) is a benchmark transparent conducting oxide material. We prepared ligand-free but colloidal ITO (8 nm, 10 % Sn(4+) ) nanocrystals (NCs) by using a post-synthesis surface-modification reaction. (CH3 )3 OBF4 removes the native oleylamine ligand from NC surfaces to give ligand-free, positively charged NCs that form a colloidal dispersion in polar solvents. Both oleylamine-capped and ligand-free ITO NCs exhibit intense absorption peaks, due to localized surface plasmon resonance (LSPR) at around λ=1950 nm. Compared with oleylamine-capped NCs, the electrical resistivity of ligand-free ITO NCs is lower by an order of magnitude (≈35 mΩ cm(-1) ). Resistivity over a wide range of temperatures can be consistently described as a composite of metallic ITO grains embedded in an insulating matrix by using a simple equivalent circuit, which provides an insight into the conduction mechanism in these systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimal ex vivo expansion of neutrophils from PBSC CD34+ cells by a combination of SCF, Flt3-L and G-CSF and its inhibition by further addition of TPO

Directory of Open Access Journals (Sweden)

Turner Marc L

2007-10-01

Full Text Available Abstract Background Autologous mobilised peripheral blood stem cell (PBSC transplantation is now a standard approach in the treatment of haematological diseases to reconstitute haematopoiesis following myeloablative chemotherapy. However, there remains a period of severe neutropenia and thrombocytopenia before haematopoietic reconstitution is achieved. Ex vivo expanded PBSC have been employed as an adjunct to unmanipulated HSC transplantation, but have tended to be produced using complex cytokine mixtures aimed at multilineage (neutrophil and megakaryocyte progenitor expansion. These have been reported to reduce or abrogate neutropenia but have little major effect on thrombocytopenia. Selective megakaryocyte expansion has been to date ineffective in reducing thrombocytopenia. This study was implemented to evaluate neutrophil specific rather than multilineage ex vivo expansion of PBSC for specifically focusing on reduction or abrogation of neutropenia. Methods CD34+ cells (PBSC were enriched from peripheral blood mononuclear cells following G-CSF-mobilisation and cultured with different permutations of cytokines to determine optimal cytokine combinations and doses for expansion and functional differentiation and maturation of neutrophils and their progenitors. Results were assessed by cell number, morphology, phenotype and function. Results A simple cytokine combination, SCF + Flt3-L + G-CSF, synergised to optimally expand and mature neutrophil progenitors assessed by cell number, phenotype, morphology and function (superoxide respiratory burst measured by chemiluminescence. G-CSF appears mandatory for functional maturation. Addition of other commonly employed cytokines, IL-3 and IL-6, had no demonstrable additive effect on numbers or function compared to this optimal combination. Addition of TPO, commonly included in multilineage progenitor expansion for development of megakaryocytes, reduced the maturation of neutrophil progenitors as assessed

1,2,3-triazolyl amino acids as AMPA receptor ligands

DEFF Research Database (Denmark)

Stanley, Nathan J.; Pedersen, Daniel Sejer; Nielsen, Birgitte

2010-01-01

The central nervous system glutamate receptors are an important target for drug discovery. Herein we report initial investigations into the synthesis and glutamate receptor activity of 1,2,3-triazolyl amino acids. Two compounds were found to be selective AMPA receptor ligands, which warrant further...

1,3-thiazole as suitable antenna ligand for lanthanide photoluminescence in [LnCl{sub 3}(thz){sub 4}].0.5thz, Ln = Sm, Eu, Gd, Tb, Dy

Energy Technology Data Exchange (ETDEWEB)

Dannenbauer, Nicole; Mueller-Buschbaum, Klaus [Wuerzburg Univ. (Germany). Inst. for Inorganic Chemistry; Kuzmanoski, Ana; Feldmann, Claus [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. for Inorganic Chemistry

2014-02-15

The series of luminescent monomeric lanthanide thiazole complexes [LnCl{sub 3}(thz){sub 4}].0.5thz (Ln = Sm, Eu, Gd, Tb, Dy; thz = 1,3-thiazole) has been synthesised and characterised by powder and single-crystal X-ray diffraction, IR and photoluminescence spectroscopy, DTA/TG as well as elemental analysis. The colourless compounds exhibit photoluminescence in the visible region with varying quantum efficiencies up to QY = 48 % for [LnCl{sub 3}(thz){sub 4}].0.5thz. Both, the lanthanide ions as well as the thiazole ligand contribute to the luminescence. Excitation can be achieved via intra-4f transitions and by exciting the ligand, emission is observed mainly from the lanthanide ions again by 4f transitions. Thiazole can transfer energy to the lanthanide ions, which further feeds the lanthanide emission by an efficient antenna effect even at room temperature. The lanthanide ions show pentagonal-bipyramidal coordination by three chloride anions and four N atoms of 1,3-thiazole, which leads to a strong {sup 5}D{sub 0} → {sup 7}F{sub 4} transition for europium. Significant differences arise as compared to thiophene complexes because no sulphur atom is involved in the metal coordination, as the thiazole ligand is solely coordinated via its nitrogen function. (orig.)

Zn and Fe complexes containing a redox active macrocyclic biquinazoline ligand.

Science.gov (United States)

Banerjee, Priyabrata; Company, Anna; Weyhermüller, Thomas; Bill, Eckhard; Hess, Corinna R

2009-04-06

A series of iron and zinc complexes has been synthesized, coordinated by the macrocyclic biquinazoline ligand, 2-4:6-8-bis(3,3,4,4-tetramethyldihydropyrrolo)-10-15-(2,2'-biquinazolino)-[15]-1,3,5,8,10,14-hexaene-1,3,7,9,11,14-N(6) (Mabiq). The Mabiq ligand consists of a bipyrimidine moiety and two dihydropyrrole units. The electronic structures of the metal-Mabiq complexes have been characterized using spectroscopic and density-functional theory (DFT) computational methods. The parent zinc complex exhibits a ligand-centered reduction to generate the metal-coordinated Mabiq radical dianion, establishing the redox non-innocence of this ligand. Iron-Mabiq complexes have been isolated in three oxidation states. This redox series includes low-spin ferric and low-spin ferrous species, as well as an intermediate-spin Fe(II) compound. In the latter complex, the iron ion is antiferromagnetically coupled to a Mabiq-centered pi-radical. The results demonstrate the rich redox chemistry and electronic properties of metal complexes coordinated by the Mabiq ligand.

On dependence of stability of lanthanide(3) complexes with coloured ligands on the element nature

International Nuclear Information System (INIS)

Poluehktov, N.S.; Meshkova, S.B.; Rusakova, N.V.

1984-01-01

The change in the colour intensity of Ln(3) complexes with coloured ligands (methyl thymol blue, glycine cresol red, stilbazo, glycine thymol blue, methyl ortanyl S, ortanyl B, phthalexone S, semiphthalexone S, cresolphtalexone, sulfarsazen) in the natural series of lanthanoids is considered. A correlation equation is suggested that permits to describe the relative colour intensity (quenching molar coefficients, stability constants) of complexes in the series of lanthanide(3) ions versus the number of f-electrons, spin and orbital quantum numbers of the ground states. Using the ratio obtained it is possible to calculate the values of appropriate functions of complexes of elements for which such data are not available

Using the angiogenic factors sFlt-1 and PlGF with Doppler ultrasound of the uterine artery for confirming preeclampsia.

Science.gov (United States)

Bahlmann, Franz; Al Naimi, Ammar

2016-11-01

The aim of this study is to assess the value of the angiogenic factors for diagnosing preeclampsia and predicting the severity of manifestation. A secondary aim is assessing the combination of the uterine artery Doppler with the angiogenic factors for improving the diagnostic power. This is a prospective single center study in a tertiary referral hospital. This study includes 728 individual patients. Inclusion criteria were singleton pregnancies, a referral to the hospital with suspicion of preeclampsia and any one or combination of the following symptoms: headache, upper abdominal pain, edema, and hypertension. Patients with complications that would affect the course of the pregnancy, such as placenta praevia, premature preterm rupture of membranes, breech presentation, and fetal chromosomal or structural anomalies, were excluded from the study. Blood samples collection and uterine artery Doppler ultrasound were performed at time of recruitment. The differences in sFlt-1, PlGF, and their quotient among normal collective and patients with preeclampsia were analyzed. Doppler ultrasound was performed by one of four highly qualified sonographers. Wilcoxon-Mann-Whitney U test, Spearman's rank correlation, receiver operating characteristic curves, Chi-square test, and logistic regression were used in the analysis. A total of 1003 individual samples for the angiogenic factors were included in the analysis. 584 out of the recruited 728 patients had follow-up data with delivery information at the study hospital. Patients with preeclampsia show a significant increase in sFlt-1, which directly correlate with the increased severity of manifestation (Spearman's ρ 0.49). The sFlt-1 cut-off value of 5424 pg/ml confirms preeclampsia with 83.7 % sensitivity, 68.1 % specificity, and 24 % misclassification rate. Preeclampsia patients also show a significant decrease in PlGF, which negatively correlates with the increased severity of manifestation (Spearman's ρ -0.39). A Pl

Large scale free energy calculations for blind predictions of protein-ligand binding: the D3R Grand Challenge 2015.

Science.gov (United States)

Deng, Nanjie; Flynn, William F; Xia, Junchao; Vijayan, R S K; Zhang, Baofeng; He, Peng; Mentes, Ahmet; Gallicchio, Emilio; Levy, Ronald M

2016-09-01

We describe binding free energy calculations in the D3R Grand Challenge 2015 for blind prediction of the binding affinities of 180 ligands to Hsp90. The present D3R challenge was built around experimental datasets involving Heat shock protein (Hsp) 90, an ATP-dependent molecular chaperone which is an important anticancer drug target. The Hsp90 ATP binding site is known to be a challenging target for accurate calculations of ligand binding affinities because of the ligand-dependent conformational changes in the binding site, the presence of ordered waters and the broad chemical diversity of ligands that can bind at this site. Our primary focus here is to distinguish binders from nonbinders. Large scale absolute binding free energy calculations that cover over 3000 protein-ligand complexes were performed using the BEDAM method starting from docked structures generated by Glide docking. Although the ligand dataset in this study resembles an intermediate to late stage lead optimization project while the BEDAM method is mainly developed for early stage virtual screening of hit molecules, the BEDAM binding free energy scoring has resulted in a moderate enrichment of ligand screening against this challenging drug target. Results show that, using a statistical mechanics based free energy method like BEDAM starting from docked poses offers better enrichment than classical docking scoring functions and rescoring methods like Prime MM-GBSA for the Hsp90 data set in this blind challenge. Importantly, among the three methods tested here, only the mean value of the BEDAM binding free energy scores is able to separate the large group of binders from the small group of nonbinders with a gap of 2.4 kcal/mol. None of the three methods that we have tested provided accurate ranking of the affinities of the 147 active compounds. We discuss the possible sources of errors in the binding free energy calculations. The study suggests that BEDAM can be used strategically to discriminate

Interaction of calreticulin with CD40 ligand, TRAIL and Fas ligand

DEFF Research Database (Denmark)

Duus, K; Pagh, R T; Holmskov, U

2007-01-01

is utilized by many other functionally diverse molecules and in this work the interaction of calreticulin with C1q and structurally similar molecules was investigated. In addition to C1q and MBL, CD40 ligand (CD40L), tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and Fas ligand (FasL) were...... found to bind calreticulin strongly. A low level or no binding was observed for adiponectin, tumour necrosis factor-alpha (TNF-alpha), CD30L, surfactant protein-A and -D and collagen VIII. The interaction with calreticulin required a conformational change in CD40L, TRAIL and FasL and showed the same...

PPARγ Ligands Regulate Noncontractile and Contractile Functions of Airway Smooth Muscle: Implications for Asthma Therapy

Directory of Open Access Journals (Sweden)

Chantal Donovan

2012-01-01

Full Text Available In asthma, the increase in airway smooth muscle (ASM can contribute to inflammation, airway wall remodeling and airway hyperresponsiveness (AHR. Targetting peroxisome proliferator-activated receptor γ (PPARγ, a receptor upregulated in ASM in asthmatic airways, may provide a novel approach to regulate these contributions. This review summarises experimental evidence that PPARγ ligands, such as rosiglitazone (RGZ and pioglitazone (PGZ, inhibit proliferation and inflammatory cytokine production from ASM in vitro. In addition, inhaled administration of these ligands reduces inflammatory cell infiltration and airway remodelling in mouse models of allergen-induced airways disease. PPARγ ligands can also regulate ASM contractility, with acute treatment eliciting relaxation of mouse trachea in vitro through a PPARγ-independent mechanism. Chronic treatment can protect against the loss of bronchodilator sensitivity to β2-adrenoceptor agonists and inhibit the development of AHR associated with exposure to nicotine in utero or following allergen challenge. Of particular interest, a small clinical trial has shown that oral RGZ treatment improves lung function in smokers with asthma, a group that is generally unresponsive to conventional steroid treatment. These combined findings support further investigation of the potential for PPARγ agonists to target the noncontractile and contractile functions of ASM to improve outcomes for patients with poorly controlled asthma.

LigandRFs: random forest ensemble to identify ligand-binding residues from sequence information alone

KAUST Repository

Chen, Peng

2014-12-03

Background Protein-ligand binding is important for some proteins to perform their functions. Protein-ligand binding sites are the residues of proteins that physically bind to ligands. Despite of the recent advances in computational prediction for protein-ligand binding sites, the state-of-the-art methods search for similar, known structures of the query and predict the binding sites based on the solved structures. However, such structural information is not commonly available. Results In this paper, we propose a sequence-based approach to identify protein-ligand binding residues. We propose a combination technique to reduce the effects of different sliding residue windows in the process of encoding input feature vectors. Moreover, due to the highly imbalanced samples between the ligand-binding sites and non ligand-binding sites, we construct several balanced data sets, for each of which a random forest (RF)-based classifier is trained. The ensemble of these RF classifiers forms a sequence-based protein-ligand binding site predictor. Conclusions Experimental results on CASP9 and CASP8 data sets demonstrate that our method compares favorably with the state-of-the-art protein-ligand binding site prediction methods.

Complete identification of E-selectin ligands on neutrophils reveals distinct functions of PSGL-1, ESL-1, and CD44.

Science.gov (United States)

Hidalgo, Andrés; Peired, Anna J; Wild, Martin; Vestweber, Dietmar; Frenette, Paul S

2007-04-01

The selectins and their ligands are required for leukocyte extravasation during inflammation. Several glycoproteins have been suggested to bind to E-selectin in vitro, but the complete identification of its physiological ligands has remained elusive. Here, we showed that E-selectin ligand-1 (ESL-1), P-selectin glycoprotein ligand-1 (PSGL-1), and CD44 encompassed all endothelial-selectin ligand activity on neutrophils by using gene- and RNA-targeted loss of function. PSGL-1 played a major role in the initial leukocyte capture, whereas ESL-1 was critical for converting initial tethers into steady slow rolling. CD44 controlled rolling velocity and mediated E-selectin-dependent redistribution of PSGL-1 and L-selectin to a major pole on slowly rolling leukocytes through p38 signaling. These results suggest distinct and dynamic contributions of these three glycoproteins in selectin-mediated neutrophil adhesion and signaling.

Automatic synthesis of 3'-Deoxy-3'-18F-fluorothymidine using a domestic FDG module

International Nuclear Information System (INIS)

Zhang Jinming; Zhang Xiaojun; Li Yungang; Liu Jian; Tian Jiahe

2012-01-01

3'-Deoxy-3'-[ 18 F] fluorothymidine ( 18 F-FLT) is a radiotracer for the imaging of tumor proliferation. A clinically applicable automatic system for the preparation of 18 F-FLT was developed by modifying a domestic 18 F-FDG synthesizer with semipreparative HPLC. Fifteen milligrams of 3-N-Boc-5'-O-dimethoxytrityl-3'-O-nosyl-thymidine were dissolved in 0.5 mL DMSO and reacted with dried 18 F-fluoride at 100 ℃ for 5 min. The obtained material was hydrolyzed with 1 mol/L HCl at 110 ℃ for 5 min, and then neutralized with 2 mol/ L NaOH before HPLC purification was performed. The desired radioactive fraction was collected after passing through a 0.22 m filter into a 30 mL vial as the final product. The 18 F- FLT labelling yield was found to be 67.5% (n=8) by the radio-TLC method, and 39.4% (n=6) by the HPLC method. The yield as the final product for clinical use was 21.2% (n=3, not corrected for decay). The total preparation time, including the time for HPLC purification, was 30 min. The radiochemical purity of the final product was over 99%, and the specific activity was higher than 740 TBq/mg (180 PBq/mol). The final product was stable for more than 6 h in the 10% alcohol solution. This preparation system with semi-preparative HPLC enables us to produce 18 F-FLT with a stable yield for clinical use. (authors)

Predicting Nanocrystal Shape through Consideration of Surface-Ligand Interactions

KAUST Repository

Bealing, Clive R.

2012-03-27

Density functional calculations for the binding energy of oleic acid-based ligands on Pb-rich {100} and {111} facets of PbSe nanocrystals determine the surface energies as a function of ligand coverage. Oleic acid is expected to bind to the nanocrystal surface in the form of lead oleate. The Wulff construction predicts the thermodynamic equilibrium shape of the PbSe nanocrystals. The equilibrium shape is a function of the ligand surface coverage, which can be controlled by changing the concentration of oleic acid during synthesis. The different binding energy of the ligand on the {100} and {111} facets results in different equilibrium ligand coverages on the facets, and a transition in the equilibrium shape from octahedral to cubic is predicted when increasing the ligand concentration during synthesis. © 2012 American Chemical Society.

Structural Insights into Selective Ligand-Receptor Interactions Leading to Receptor Inactivation Utilizing Selective Melanocortin 3 Receptor Antagonists.

Science.gov (United States)

Cai, Minying; Marelli, Udaya Kiran; Mertz, Blake; Beck, Johannes G; Opperer, Florian; Rechenmacher, Florian; Kessler, Horst; Hruby, Victor J

2017-08-15

Systematic N-methylated derivatives of the melanocortin receptor ligand, SHU9119, lead to multiple binding and functional selectivity toward melanocortin receptors. However, the relationship between N-methylation-induced conformational changes in the peptide backbone and side chains and melanocortin receptor selectivity is still unknown. We conducted comprehensive conformational studies in solution of two selective antagonists of the third isoform of the melanocortin receptor (hMC3R), namely, Ac-Nle-c[Asp-NMe-His 6 -d-Nal(2') 7 -NMe-Arg 8 -Trp 9 -Lys]-NH 2 (15) and Ac-Nle-c[Asp-His 6 -d-Nal(2') 7 -NMe-Arg 8 -NMe-Trp 9 -NMe-Lys]-NH 2 (17). It is known that the pharmacophore (His 6 -DNal 7 -Arg 8 -Trp 9 ) of the SHU-9119 peptides occupies a β II-turn-like region with the turn centered about DNal 7 -Arg 8 . The analogues with hMC3R selectivity showed distinct differences in the spatial arrangement of the Trp 9 side chains. In addition to our NMR studies, we also carried out molecular-level interaction studies of these two peptides at the homology model of hMC3R. Earlier chimeric human melanocortin 3 receptor studies revealed insights regarding the binding and functional sites of hMC3R selectivity. Upon docking of peptides 15 and 17 to the binding pocket of hMC3R, it was revealed that Arg 8 and Trp 9 side chains are involved in a majority of the interactions with the receptor. While Arg 8 forms polar contacts with D154 and D158 of hMC3R, Trp 9 utilizes π-π stacking interactions with F295 and F298, located on the transmembrane domain of hMC3R. It is hypothesized that as the frequency of Trp 9 -hMC3R interactions decrease, antagonistic activity increases. The absence of any interactions of the N-methyl groups with hMC3R suggests that their primary function is to modulate backbone conformations of the ligands.

Construction of three metal-organic frameworks based on multifunctional T-shaped tripodal ligands, H3PyImDC

KAUST Repository

Jing, Xuemin

2010-08-04

Three novel metal-organic frameworks (MOFs), |(C3H 7NO)2(H2O)|[Zn3(C10H 5N3O4)3(C3H 7NO)2] (1), |(H2O)5(H 3O)(NO3)|[Nd2(C10H5N 3O4)3(H2O)4] (2), and |(H2O)2|[Nd3(C10H5N 3O4)3(C10H4N 3O4)] (3), based on the T-shaped tripodal ligands 2-(pyridine-4-yl)-1H-4,5-imidazoledicarboxylic acid and 2-(pyridine-3-yl)-1H-4, 5-imidazoledicarboxylic acid (H3PyImDC), have been constructed under solvo-/hydrothermal conditions. The diverse coordination modes of H 3PyImDC ligands have afforded the assembly of three novel compounds. In compound 1, two oxygen atoms and three nitrogen atoms of the H 3PyImDC ligand, a T-shaped linker, coordinate to two zinc centers to form a novel bbm net with two distinct channels along the [100] and [001] directions. In compound 2, H3PyImDC ligands coordinate to neodymium centers to form a ladder-like chain which then interacts with a water molecules chain via hydrogen-bondings to construct a 3D supermolecular structure. In compound 3, H3PyImDC ligands, a T-shaped linker, coordinate to neodymium centers to form a (3,6)-connected net with an ant topology. In compounds 1-3, the two H3PyImDC ligands exhibit different coordination modes with zinc and neodymium centers, which afforded the expected structural diversity. Additionally, all three compounds exhibit strong fluorescence emissions in the solid state at room temperature. © 2010 American Chemical Society.

Application of 3D-QSAR in the rational design of receptor ligands and enzyme inhibitors.

Science.gov (United States)

Mor, Marco; Rivara, Silvia; Lodola, Alessio; Lorenzi, Simone; Bordi, Fabrizio; Plazzi, Pier Vincenzo; Spadoni, Gilberto; Bedini, Annalida; Duranti, Andrea; Tontini, Andrea; Tarzia, Giorgio

2005-11-01

Quantitative structure-activity relationships (QSARs) are frequently employed in medicinal chemistry projects, both to rationalize structure-activity relationships (SAR) for known series of compounds and to help in the design of innovative structures endowed with desired pharmacological actions. As a difference from the so-called structure-based drug design tools, they do not require the knowledge of the biological target structure, but are based on the comparison of drug structural features, thus being defined ligand-based drug design tools. In the 3D-QSAR approach, structural descriptors are calculated from molecular models of the ligands, as interaction fields within a three-dimensional (3D) lattice of points surrounding the ligand structure. These descriptors are collected in a large X matrix, which is submitted to multivariate analysis to look for correlations with biological activity. Like for other QSARs, the reliability and usefulness of the correlation models depends on the validity of the assumptions and on the quality of the data. A careful selection of compounds and pharmacological data can improve the application of 3D-QSAR analysis in drug design. Some examples of the application of CoMFA and CoMSIA approaches to the SAR study and design of receptor or enzyme ligands is described, pointing the attention to the fields of melatonin receptor ligands and FAAH inhibitors.

First trimester uterine artery Doppler, sFlt-1 and PlGF to predict preeclampsia in a high-risk population.

Science.gov (United States)

Diguisto, Caroline; Piver, Eric; Gouge, Amélie Le; Eboue, Florence; Vaillant, Claudine Le; Maréchaud, Martine; Goua, Valérie; Giraudeau, Bruno; Perrotin, Franck

2017-07-01

The study aims to evaluate the accuracy of combining uterine artery Doppler (UAD), PlGF and sFlt-1 in the first trimester for preeclampsia screening. Prospectively enrolled women at high risk of preeclampsia were included. Transabdominal UAD measurements and serum biomarkers were collected between 11 and 13 weeks of gestation in three university hospitals and in one general hospital. The main outcome was preeclampsia. UAD parameters and biomarker levels among women with preeclampsia were compared with those of women in the unaffected group in univariate and multivariate analyses. Out of 226 women included from May 2007 to January 2011, 27 (11.9%) women developed preeclampsia. Among women affected by preeclampsia, the lowest pulsatility index was higher (p = 0.02), bilateral notching was more frequent (p = 0.01), and PlGF was lower (p preeclampsia, but neither sFlt-1 nor any UAD indices improved the prediction of preeclampsia.

C-C coupling of N-heterocycles at the fac-Re(CO)(3) fragment: synthesis of pyridylimidazole and bipyridine ligands.

Science.gov (United States)

Viguri, Maialen Espinal; Pérez, Julio; Riera, Lucía

2014-05-05

A new family of cationic rhenium tricarbonyl complexes with either two N-alkylimidazole (N-RIm) and one pyridine (Py) ligand, or two pyridine and one N-RIm ligand, [Re(CO)3 (N-RIm)(3-x) (Py)x ](+) , has been prepared. The reaction of these complexes with a strong base, followed by an oxidant, selectively afforded 2,2'-pyridylimidazole complexes as the result of intramolecular dehydrogenative CC coupling reactions. For tris(pyridine) complexes [Re(CO)3 (Py)3 ](+) the reaction pattern upon a deprotonation/oxidation sequence is maintained, which allows the generation of complexes with 2,2'-bipyridine ligands. In the particular combination of two different types of pyridine ligand in the cationic fac-Re(CO)3 complexes only the cross-coupling products with asymmetric 2,2'-bipyridine ligands were obtained; the homocoupling products were not observed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface polyPEGylation of Eu3+ doped luminescent hydroxyapatite nanorods through the combination of ligand exchange and metal free surface initiated atom transfer radical polymerization

Science.gov (United States)

Zeng, Guangjian; Liu, Meiying; Heng, Chunning; Huang, Qiang; Mao, Liucheng; Huang, Hongye; Hui, Junfeng; Deng, Fengjie; Zhang, Xiaoyong; Wei, Yen

2017-03-01

The Eu3+ doped luminescent hydroxyapatite (HAp) nanorods with uniform size and morphology can be synthesized by hydrothermal route. However, these HAp nanorods are coated by hydrophobic oleylamine, which makes them difficult to be dispersed in aqueous solution and impede their biomedical applications. In this work, Eu3+ doped luminescent polymers functionalized HAp nanorods were prepared through the combination of ligand exchange reaction and metal free surface initiated atom transfer radical polymerization (ATRP) method. In this procedure, the amino group functionalized HAp nanorods were first prepared by ligand exchange reaction using adenosine monophosphate (AMP) as ligand. Then the Br-containing initiators (HAp-Br) were introduced onto the surface of HAp-AMP nanorods through the amidation reaction. Finally, polymers functionalized HAp nanorods were prepared by metal free ATRP method using poly(ethylene glycol) methacrylate (PEGMA) as monomer and 10-phenylphenothiazine (PTH) as organic photocatalyst. The properties of these obtained HAp nanocomposites (HAP-polyPEGMA nanorods) were characterized by means of transmission electron microscopy, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis in detail. The cell imaging of these HAP-polyPEGMA nanorods was examined using laser scanning confocal microscope to evaluate their biomedical applications. We demonstrated for the first time that hydrophobic luminescent HAp nanorods can be functionalized with polyPEGMA through the combination of ligand exchange reaction and metal free surface initiated ATRP. As compared with the traditional ATRP, the metal free ATRP can overcome the toxic and fluorescence quenching effects of metal catalysts such as copper ions. More importantly, the strategy described in this work should also be utilized for fabrications of many other luminescent polymer nanocomposites due to its good monomer adoptability.

Functional characterization of the modified melanocortin peptides responsible for ligand selectivity at the human melanocortin receptors.

Science.gov (United States)

Chen, Min; Georgeson, Keith E; Harmon, Carroll M; Haskell-Luevano, Carrie; Yang, Yingkui

2006-11-01

The melanocortin system plays an important role in energy homeostasis as well as skin pigmentation, steroidogenesis and exocrine gland function. In this study, we examined eight Ac-His-Phe-Arg-Trp-NH(2) tetrapeptides that were modified at the Phe position and pharmacologically characterized their activities at the human MCR wild-types and their mutants. Our results indicate that at the hMC1R, all D stereochemical modified residues at the Phe position of peptides increase cAMP production in a dose-dependent manner. At the hMC3R, the DPhe peptide dose dependently increases cAMP production but all other three tetrapeptides were not. At the hMC4R, both the DPhe and DNal(1') peptides induce cAMP production. However, both DTyr and DNal(2') were not able to induce cAMP production. Further studies indicated that at the hMC1R M128L mutant receptor, the all D-configured tetrapeptides reduce their potencies as compared to that of hMC1R wild-type. However, at the hMC3R and hMC4R L165M and L133M mutant receptors, the DNal(2') and DTyr tetrapeptides possess agonist activity. These findings indicate that DPhe in tetrapeptide plays an important role in ligand selectivity and specific residue TM3 of the melanocortin receptors is crucial for ligand selectivity.

C-H functionalization: thoroughly tuning ligands at a metal ion, a chemist can greatly enhance catalyst's activity and selectivity.

Science.gov (United States)

Shul'pin, Georgiy B

2013-09-28

This brief essay consists of a few "exciting stories" devoted to relations within a metal-complex catalyst between a metal ion and a coordinated ligand. When, as in the case of a human couple, the rapport of the partners is cordial and a love cements these relations, a chemist finds an ideal married couple, in other words he obtains a catalyst of choice which allows him to functionalize C-H bonds very efficiently and selectively. Examples of such lucky marriages in the catalytic world of ions and ligands are discussed here. Activity of the catalyst is characterized by turnover number (TON) or turnover frequency (TOF) as well as by yield of a target product. Introducing a chelating N,N- or N,O-ligand to the catalyst molecule (this can be an iron or manganese derivative) sharply enhances its activity. However, the activity of vanadium derivatives (with additionally added to the solution pyrazinecarboxylic acid, PCA) as well as of various osmium complexes does not dramatically depend on the nature of ligands surrounding metal ions. Complexes of these metals are very efficient catalysts in oxidations with H2O2. Osmium derivatives are record-holders exhibiting extremely high TONs whereas vanadium complexes are on the second position. Finally, elegant examples of alkane functionalization on the ions of non-transition metals (aluminium, gallium etc.) are described when one ligand within the metal complex (namely, hydroperoxyl ligand HOO(-)) helps other ligand of this complex (H2O2 molecule coordinated to the metal) to disintegrate into two species, generating very reactive hydroxyl radical. Hydrogen peroxide molecule, even ligated to the metal ion, is perfectly stable without the assistance of the neighboring HOO(-) ligand. This ligand can be easily oxidized donating an electron to its partner ligand (H2O2). In an analogous case, when the central ion in the catalyst is a transition metal, this ion changing its oxidation state can donate an electron to the coordinated H2O2

Binding Ligand Prediction for Proteins Using Partial Matching of Local Surface Patches

Directory of Open Access Journals (Sweden)

Lee Sael

2010-12-01

Full Text Available Functional elucidation of uncharacterized protein structures is an important task in bioinformatics. We report our new approach for structure-based function prediction which captures local surface features of ligand binding pockets. Function of proteins, specifically, binding ligands of proteins, can be predicted by finding similar local surface regions of known proteins. To enable partial comparison of binding sites in proteins, a weighted bipartite matching algorithm is used to match pairs of surface patches. The surface patches are encoded with the 3D Zernike descriptors. Unlike the existing methods which compare global characteristics of the protein fold or the global pocket shape, the local surface patch method can find functional similarity between non-homologous proteins and binding pockets for flexible ligand molecules. The proposed method improves prediction results over global pocket shape-based method which was previously developed by our group.

Binding ligand prediction for proteins using partial matching of local surface patches.

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Sael, Lee; Kihara, Daisuke

2010-01-01

Functional elucidation of uncharacterized protein structures is an important task in bioinformatics. We report our new approach for structure-based function prediction which captures local surface features of ligand binding pockets. Function of proteins, specifically, binding ligands of proteins, can be predicted by finding similar local surface regions of known proteins. To enable partial comparison of binding sites in proteins, a weighted bipartite matching algorithm is used to match pairs of surface patches. The surface patches are encoded with the 3D Zernike descriptors. Unlike the existing methods which compare global characteristics of the protein fold or the global pocket shape, the local surface patch method can find functional similarity between non-homologous proteins and binding pockets for flexible ligand molecules. The proposed method improves prediction results over global pocket shape-based method which was previously developed by our group.

Functional characterization of neurotransmitter activation and modulation in a nematode model ligand-gated ion channel.

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Heusser, Stephanie A; Yoluk, Özge; Klement, Göran; Riederer, Erika A; Lindahl, Erik; Howard, Rebecca J

2016-07-01

The superfamily of pentameric ligand-gated ion channels includes neurotransmitter receptors that mediate fast synaptic transmission in vertebrates, and are targets for drugs including alcohols, anesthetics, benzodiazepines, and anticonvulsants. However, the mechanisms of ion channel opening, gating, and modulation in these receptors leave many open questions, despite their pharmacological importance. Subtle conformational changes in both the extracellular and transmembrane domains are likely to influence channel opening, but have been difficult to characterize given the limited structural data available for human membrane proteins. Recent crystal structures of a modified Caenorhabditis elegans glutamate-gated chloride channel (GluCl) in multiple states offer an appealing model system for structure-function studies. However, the pharmacology of the crystallographic GluCl construct is not well established. To establish the functional relevance of this system, we used two-electrode voltage-clamp electrophysiology in Xenopus oocytes to characterize activation of crystallographic and native-like GluCl constructs by L-glutamate and ivermectin. We also tested modulation by ethanol and other anesthetic agents, and used site-directed mutagenesis to explore the role of a region of Loop F which was implicated in ligand gating by molecular dynamics simulations. Our findings indicate that the crystallographic construct functionally models concentration-dependent agonism and allosteric modulation of pharmacologically relevant receptors. Specific substitutions at residue Leu174 in loop F altered direct L-glutamate activation, consistent with computational evidence for this region's role in ligand binding. These insights demonstrate conservation of activation and modulation properties in this receptor family, and establish a framework for GluCl as a model system, including new possibilities for drug discovery. In this study, we elucidate the validity of a modified glutamate

Noninvasive k3 estimation method for slow dissociation PET ligands: application to [11C]Pittsburgh compound B.

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Sato, Koichi; Fukushi, Kiyoshi; Shinotoh, Hitoshi; Shimada, Hitoshi; Hirano, Shigeki; Tanaka, Noriko; Suhara, Tetsuya; Irie, Toshiaki; Ito, Hiroshi

2013-11-16

Recently, we reported an information density theory and an analysis of three-parameter plus shorter scan than conventional method (3P+) for the amyloid-binding ligand [11C]Pittsburgh compound B (PIB) as an example of a non-highly reversible positron emission tomography (PET) ligand. This article describes an extension of 3P + analysis to noninvasive '3P++' analysis (3P + plus use of a reference tissue for input function). In 3P++ analysis for [11C]PIB, the cerebellum was used as a reference tissue (negligible specific binding). Fifteen healthy subjects (NC) and fifteen Alzheimer's disease (AD) patients participated. The k3 (index of receptor density) values were estimated with 40-min PET data and three-parameter reference tissue model and were compared with that in 40-min 3P + analysis as well as standard 90-min four-parameter (4P) analysis with arterial input function. Simulation studies were performed to explain k3 biases observed in 3P++ analysis. Good model fits of 40-min PET data were observed in both reference and target regions-of-interest (ROIs). High linear intra-subject (inter-15 ROI) correlations of k3 between 3P++ (Y-axis) and 3P + (X-axis) analyses were shown in one NC (r2 = 0.972 and slope = 0.845) and in one AD (r2 = 0.982, slope = 0.655), whereas inter-subject k3 correlations in a target region (left lateral temporal cortex) from 30 subjects (15 NC + 15 AD) were somewhat lower (r2 = 0.739 and slope = 0.461). Similar results were shown between 3P++ and 4P analyses: r2 = 0.953 for intra-subject k3 in NC, r2 = 0.907 for that in AD and r2 = 0.711 for inter-30 subject k3. Simulation studies showed that such lower inter-subject k3 correlations and significant negative k3 biases were not due to unstableness of 3P++ analysis but rather to inter-subject variation of both k2 (index of brain-to-blood transport) and k3 (not completely negligible) in the reference region. In [11C]PIB, the applicability of 3

Strong Ligand-Protein Interactions Derived from Diffuse Ligand Interactions with Loose Binding Sites.

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Marsh, Lorraine

2015-01-01

Many systems in biology rely on binding of ligands to target proteins in a single high-affinity conformation with a favorable ΔG. Alternatively, interactions of ligands with protein regions that allow diffuse binding, distributed over multiple sites and conformations, can exhibit favorable ΔG because of their higher entropy. Diffuse binding may be biologically important for multidrug transporters and carrier proteins. A fine-grained computational method for numerical integration of total binding ΔG arising from diffuse regional interaction of a ligand in multiple conformations using a Markov Chain Monte Carlo (MCMC) approach is presented. This method yields a metric that quantifies the influence on overall ligand affinity of ligand binding to multiple, distinct sites within a protein binding region. This metric is essentially a measure of dispersion in equilibrium ligand binding and depends on both the number of potential sites of interaction and the distribution of their individual predicted affinities. Analysis of test cases indicates that, for some ligand/protein pairs involving transporters and carrier proteins, diffuse binding contributes greatly to total affinity, whereas in other cases the influence is modest. This approach may be useful for studying situations where "nonspecific" interactions contribute to biological function.

Surface polyPEGylation of Eu"3"+ doped luminescent hydroxyapatite nanorods through the combination of ligand exchange and metal free surface initiated atom transfer radical polymerization

International Nuclear Information System (INIS)

Zeng, Guangjian; Liu, Meiying; Heng, Chunning; Huang, Qiang; Mao, Liucheng; Huang, Hongye; Hui, Junfeng; Deng, Fengjie; Zhang, Xiaoyong; Wei, Yen

2017-01-01

Highlights: • Surface modification of HAp nanorods through the combination of ligand exchange reaction and metal free SI-ATRP. • HAp-polyPEGMA displayed high water dispersibility, good biocompatibility and biological imaging capability. • Metal free ATRP can overcome the toxic and fluorescence quenching effects of metal catalysts of conventional ATRP. - Abstract: The Eu"3"+ doped luminescent hydroxyapatite (HAp) nanorods with uniform size and morphology can be synthesized by hydrothermal route. However, these HAp nanorods are coated by hydrophobic oleylamine, which makes them difficult to be dispersed in aqueous solution and impede their biomedical applications. In this work, Eu"3"+ doped luminescent polymers functionalized HAp nanorods were prepared through the combination of ligand exchange reaction and metal free surface initiated atom transfer radical polymerization (ATRP) method. In this procedure, the amino group functionalized HAp nanorods were first prepared by ligand exchange reaction using adenosine monophosphate (AMP) as ligand. Then the Br-containing initiators (HAp-Br) were introduced onto the surface of HAp-AMP nanorods through the amidation reaction. Finally, polymers functionalized HAp nanorods were prepared by metal free ATRP method using poly(ethylene glycol) methacrylate (PEGMA) as monomer and 10-phenylphenothiazine (PTH) as organic photocatalyst. The properties of these obtained HAp nanocomposites (HAP-polyPEGMA nanorods) were characterized by means of transmission electron microscopy, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis in detail. The cell imaging of these HAP-polyPEGMA nanorods was examined using laser scanning confocal microscope to evaluate their biomedical applications. We demonstrated for the first time that hydrophobic luminescent HAp nanorods can be functionalized with polyPEGMA through the combination of ligand exchange reaction and metal free surface initiated

Transformations of functional groups attached to cyclopentadienyl or related ligands in group 4 metal complexes

Czech Academy of Sciences Publication Activity Database

Pinkas, Jiří; Lamač, Martin

2015-01-01

Roč. 296, JUL 2015 (2015), s. 45-90 ISSN 0010-8545 R&D Projects: GA ČR(CZ) GA14-08531S Institutional support: RVO:61388955 Keywords : Zirconium * Functionalized cyclopentadienyl ligands * Titanium Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 12.994, year: 2015

Growth Modeling of the Maternal Cytokine Milieu throughout Normal Pregnancy: Macrophage-Derived Chemokine Decreases as Inflammation/Counterregulation Increases

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Shernan G. Holtan

2015-01-01

Full Text Available Several recent studies have shown differences in the maternal immune milieu at different phases of pregnancy, but most studies have been cross-sectional or of relatively few time points. Levels of 42 cytokines were determined using a multiplex bead-based assay on archived serum from a cohort of pregnant women N=16 at median of 18 time points tested, from the first trimester through to parturition, per woman. Unconditional growth modeling was then used to determine time-dependent changes in levels of these cytokines. Macrophage-derived chemokine (MDC, aka CCL22 decreases as pregnancy progresses. IL-1β, IL-6, IL-8, IL-12p70, IL-13, IL-15, IP-10, and FLT3-ligand increase as a function of gestational weeks, and IFNα2, IL-1ra, IL-3, IL-9, IL-12p40, and soluble CD40 ligand increase as a function of trimester. As pregnancy normally progresses, a maternal shift away from a type 2-biased immune response and toward an inflammatory/counterregulatory response is observed.

Organic ligand-induced dissolution kinetics of antimony trioxide

Institute of Scientific and Technical Information of China (English)

Xingyun Hu; Mengchang He

2017-01-01

The influence of low-molecular-weight dissolved organic matter (LMWDOM) on the dissolution rate of Sb2O3 was investigated.Some representative LMWDOMs with carboxyl,hydroxyl,hydrosulfuryl and amidogen groups occurring naturally in the solution were chosen,namely oxalic acid,citric acid,tartaric acid,EDTA,salicylic acid,phthalandione,glycine,thiolactic acid,xylitol,glucose and catechol.These LMWDOMs were dissolved in inert buffers at pH =3.7,6.6 and 8.6 and added to powdered Sb2O3 in a stirred,thermostatted reactor (25℃).The addition of EDTA,tartaric acid,thiolactic acid,citric acid and oxalic acid solutions at pH 3.7 and catechol at pH 8.6 increased the rate of release of antimony.In the 10 mmol/L thiolactic acid solution,up to 97％ by mass of the antimony was released after 120 min reaction.There was no effect on the dissolution of Sb2O3 for the other ligands.A weak correlation between dissolution rate with the dissociation constant of ligands and the stability of the dissolved complex was also found.All the results showed that the extent of the promoting effect of ligands on the dissolution of Sb2O3 was not determined by the stability of the dissolved complex,but by the dissociation constant of ligands and detachment rate of surface chelates from the mineral surface.This study can not only help in further understanding the effect of individual low-molecular-weight organic ligands,but also provides a reference to deduce the effect of natural organic matters with oxygen-bearing functional groups on the dissolution of antimony oxide minerals.

Comparative density functional study of the complexes [UO2(CO3)3]4- and [(UO2)3(CO3)6]6- in aqueous solution.

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Schlosser, Florian; Moskaleva, Lyudmila V; Kremleva, Alena; Krüger, Sven; Rösch, Notker

2010-06-28

With a relativistic all-electron density functional method, we studied two anionic uranium(VI) carbonate complexes that are important for uranium speciation and transport in aqueous medium, the mononuclear tris(carbonato) complex [UO(2)(CO(3))(3)](4-) and the trinuclear hexa(carbonato) complex [(UO(2))(3)(CO(3))(6)](6-). Focusing on the structures in solution, we applied for the first time a full solvation treatment to these complexes. We approximated short-range effects by explicit aqua ligands and described long-range electrostatic interactions via a polarizable continuum model. Structures and vibrational frequencies of "gas-phase" models with explicit aqua ligands agree best with experiment. This is accidental because the continuum model of the solvent to some extent overestimates the electrostatic interactions of these highly anionic systems with the bulk solvent. The calculated free energy change when three mono-nuclear complexes associate to the trinuclear complex, agrees well with experiment and supports the formation of the latter species upon acidification of a uranyl carbonate solution.