MH_dev_189

Inhibition of c-kit receptor tyrosine kinase activity by DB00619 SUB , a selective tyrosine kinase inhibitor . DB00619 SUB ( formerly known as CGP 57148B ) is a known inhibitor of the c-abl , bcr-abl , and platelet-derived growth-factor receptor ( P09619 REA ) tyrosine kinases . This compound is being evaluated in clinical trials for the treatment of chronic myelogenous leukemia . We sought to extend the activity profile of DB00619 SUB by testing its ability to inhibit the tyrosine kinase activity of c-kit , a receptor structurally similar to P09619 REA . We treated a c-kit expressing a human myeloid leukemia cell line , M - 07e , with DB00619 SUB before stimulation with Steel factor ( SLF ) . DB00619 SUB inhibited c-kit autophosphorylation , activation of mitogen-activated protein ( Q96HU1 ) kinase , and activation of Akt without altering total protein levels of c-kit , Q96HU1 kinase , or Akt . The concentration that produced 50 % inhibition for these effects was approximately 100 nmol / L . DB00619 SUB also significantly decreased SLF-dependent growth of M - 07e cells in a dose-dependent manner and blocked the antiapoptotic activity of SLF . In contrast , the compound had no effect on Q96HU1 kinase activation or cellular proliferation in response to granulocyte-macrophage colony-stimulating factor . We also tested the activity of DB00619 SUB in a human mast cell leukemia cell line ( HMC - 1 ) , which has an activated mutant form of c-kit . DB00619 SUB had a more potent inhibitory effect on the kinase activity of this mutant receptor than it did on ligand-dependent activation of the wild-type receptor . These findings show that DB00619 SUB selectively inhibits c-kit tyrosine kinase activity and downstream activation of target proteins involved in cellular proliferation and survival . This compound may be useful in treating cancers associated with increased c-kit kinase activity .

DB04894 MEN labeled with Tc - 99m for imaging tumors . DB04894 MEN ( RC - 160 ) , an octapeptide analog of somatostatin , has a high affinity for somatostatin receptor subtypes P30874 REA and P35346 REA . DB04894 MEN binds differently to the tumors of the breast , ovary , exocrine pancreas , prostate and colon , than octreotide another octapeptide analog of somatostatin . DB04894 MEN was labeled with Tc - 99m , a radionuclide highly suitable for scintigraphic imaging . The labeling procedure was simple , produced > 70 % yields and could be applicable to label other peptides containing a cystine bridge . HPLC analysis showed that the tracer was stable when Tc - 99m - RC - 160 was challenged with 100 fold molar excess DTPA ( diethylenetriaminepentaacetic acid ) , HSA ( human serum albumin ) or cysteine and incubated at 37 degrees C for 4 h . HPLC analysis of urine samples obtained from mice that received Tc - 99m - RC - 160 showed that the preparation was stable in vivo . Rat brain cortex membrane receptor displacement assays showed that the Kd values for Tc - 99m - RC - 160 ( 71x10 ( - 9 ) M ) and Tc - 99m - octreotide ( 86x10 ( - 9 ) M ) ( Sandostatin ( R ) ) were in nM range , and were similar to that for I - 125 - RC - 160 ( 46x10 ( - 9 ) M ) . High binding affinity of Tc - 99m - RC - 160 for human breast tumor cells SKBR - 3 was also observed . These results suggest that Tc - 99m - RC - 160 is worthy of evaluation as an agent for scintigraphic imaging of tumors rich in somatostatin receptor subtypes P30874 REA and P35346 REA .

Lipocalin 2 is required for P11274 REA - P00519 REA - induced tumorigenesis . Our previous studies indicate that reduction of lipocalin 2 ( mouse 24p3 ) expression by either anti-sense or siRNA approaches strongly reduces the overgrowth of P11274 REA - P00519 REA + mouse myeloid 32D in marrow and spleen of NOD / SCID mice . In this study , we used the mouse bone marrow transplant model to further explore the role of 24p3 in P11274 REA - P00519 REA - induced leukemia . Consistent with our previous findings , when using non-irradiated mice as recipient , donor marrow cells expressing P11274 REA - P00519 REA but lacking 24p3 did not cause leukemia or any disease after 75 days , whereas all mice receiving wild type P11274 REA - P00519 REA donor cells died with CML-like disease . An agar clone of the P11274 REA - P00519 REA + human CML cell line K562 ( P01031 REA ) that secretes relatively high levels of lipocalin 2 ( human P8 0188 ) induced suppression of hematopoiesis in spleen and marrow of mice , leading to early death in contrast to parental K562 or K562 clone ( P13671 REA ) expressing low amounts of P8 0188 . Compared with K562 cells , overexpressing P8 0188 in K562 led to a higher apoptosis rate and an atrophy phenotype in the spleen of the inoculated mice . Plasma from both leukemic mice and CML patients showed elevated lipocalin 2 levels compared with healthy individuals . Moreover , we found that a primary stable cell line from wild-type mouse marrow cells expressing P11274 REA - P00519 REA caused solid tumors in nude mice whereas a similar P11274 REA - P00519 REA + cell line from 24p3 null mice did not . These findings demonstrate that lipocalin 2 has at least two functions related to tumorigenesis , one involving apoptosis induction of normal hematopoietic cells and the other being tissue invasion by leukemia cells .

Enhancement of L-cystine transport activity and its relation to Q9UPY5 gene induction at the blood-brain barrier by diethyl maleate treatment . The purpose of the present study was to elucidate the mechanism of enhancement of L-cystine uptake at the blood-brain barrier ( BBB ) . The uptake of [ ( 14 ) C ] L-cystine and [ ( 3 ) H ] L-glutamic acid ( L - DB00142 ) was determined using a mouse brain endothelial cell line ( MBEC 4 ) as an in vitro BBB model . The mRNA levels of L-cystine / L - DB00142 exchanger , system x ( c ) ( - ) , which consists of Q9UPY5 and P08195 REA , were determined by quantitative real-time reverse transcription-polymerase chain reaction analysis . The [ ( 14 ) C ] L-cystine uptake by MBEC 4 cells appeared to be mediated via an Na ( + ) - independent saturable process . The corresponding Michaelis-Menten constant ( K ( m ) ) was 63.7 microM . In the presence of L - DB00142 , there was competitive inhibition with an inhibition constant ( K ( i ) ) of 83.5 microM . [ ( 3 ) H ] L - DB00142 uptake in the absence of Na ( + ) was saturable with a K ( m ) of 48.1 microM , and it exhibited competitive inhibition with a K ( i ) of 24.9 microM in the presence of L-cystine . The mutual inhibition between L-cystine and L - DB00142 and the type of inhibition suggest that system x ( c ) ( - ) operates in MBEC 4 cells . The Q9UPY5 and P08195 REA mRNAs were expressed in MBEC 4 cells and , following diethyl maleate ( DEM ) treatment , the Q9UPY5 mRNA level and L-cystine uptake in MBEC 4 cells were enhanced in parallel with an increase in DEM concentration ( up to 500 microM ) . Concomitantly , the glutathione concentration in MBEC 4 cells was increased . In conclusion , system x ( c ) ( - ) - mediated L-cystine uptake takes place in MBEC 4 cells . DB00138 MEN transport via system x ( c ) ( - ) at the BBB is likely to be induced under oxidative stress conditions following DEM treatment due to enhanced transcription of the Q9UPY5 gene .

Identification of basophils as a major source of hepatocyte growth factor in chronic myeloid leukemia : a novel mechanism of P11274 REA - P00519 REA - independent disease progression . Chronic myeloid leukemia ( CML ) is a hematopoietic neoplasm characterized by the Philadelphia chromosome and the related P11274 REA - P00519 REA oncoprotein . Acceleration of CML is usually accompanied by basophilia . Several proangiogenic molecules have been implicated in disease acceleration , including the hepatocyte growth factor ( P14210 REA ) . However , little is known so far about the cellular distribution and function of P14210 REA in CML . We here report that P14210 REA is expressed abundantly in purified CML basophils and in the basophil-committed CML line KU812 , whereas all other cell types examined expressed only trace amounts of P14210 REA or no P14210 REA . Interleukin 3 , a major regulator of human basophils , was found to promote P14210 REA expression in CML basophils . By contrast , P11274 REA - P00519 REA failed to induce P14210 REA synthesis in CML cells , and imatinib failed to inhibit expression of P14210 REA in these cells . Recombinant P14210 REA as well as basophil-derived P14210 REA induced endothelial cell migration in a scratch wound assay , and these effects of P14210 REA were reverted by an anti - P14210 REA antibody as well as by pharmacologic c - DB00134 inhibitors . In addition , anti - P14210 REA and c - DB00134 inhibitors were found to suppress the spontaneous growth of KU812 cells , suggesting autocrine growth regulation . Together , P14210 REA is a P11274 REA - P00519 REA - independent angiogenic and autocrine growth regulator in CML . Basophils are a unique source of P14210 REA in these patients and may play a more active role in disease-associated angiogenesis and disease progression than has so far been assumed . Our data also suggest that P14210 REA and c - DB00134 are potential therapeutic targets in CML .

Molecular markers for novel therapeutic strategies in pancreatic endocrine tumors . OBJECTIVES : Pancreatic endocrine tumors ( PETs ) share numerous features with gastrointestinal neuroendocrine ( carcinoid ) tumors . Targets of novel therapeutic strategies previously assessed in carcinoid tumors were analyzed in PETs ( 44 cases ) . METHODS : Activating mutations in P00533 REA , P10721 REA , and P16234 REA and nonresponse mutations in P01116 REA were evaluated . Copy number of P00533 REA and HER - 2 / neu was quantified by fluorescence in situ hybridization . Expression of P00533 REA , P16234 REA , P17948 REA , P36897 REA , Hsp 90 , SSTR 2A , P35346 REA , P08069 REA , P42345 REA , and P16455 REA was measured immunohistochemically . RESULTS : Elevated P00533 REA copy number was found in 38 % of cases but no P01116 REA nonresponse mutations . P17948 REA , P36897 REA , P16234 REA , P35346 REA , SSTR 2A , and P08069 REA exhibited the highest levels of expression in the largest percentages of PETs.Anticancer drugs BMS - 754807 ( selective for P08069 REA / IR ) , 17 - ( allylamino ) - 17 - demethoxygeldanamycin ( 17 - P29372 REA , targeting Hsp 90 ) , and axitinib ( directed toward P17948 REA - 3 / P16234 REA - B / P10721 REA ) induced growth inhibition of human QGP - 1 PET cells with IC50 values ( nM ) of 273 , 723 , and 743 , respectively . At growth-inhibiting concentrations , BMS - 754807 inhibited P08069 REA phosphorylation ; 17 - P29372 REA induced loss of P00533 REA , P08069 REA , and P35968 REA ; and axitinib increased P38936 REA ( P38936 REA ) expression without inhibiting P35968 REA phosphorylation . CONCLUSIONS : Results encourage further research into multidrug strategies incorporating inhibitors targeting P08069 REA or Hsp 90 and into studies of axitinib combined with conventional chemotherapeutics toxic to tumor cells in persistent growth arrest .

DB00074 MEN induction in patients receiving tacrolimus-based immunosuppressive regimens . PURPOSE : The use of basiliximab induction increased significantly in recent years based on its superior efficacy and excellent safety profile demonstrated in studies with cyclosporine-based immunosuppression . However , its clinical utility in patients receiving tacrolimus-based immunosuppressive regimens is still uncertain . METHODS : We retrospectively reviewed data of 366 low immunological risk recipients of deceased donor kidney transplants . Of them , 134 received basiliximab and tacrolimus ( TAC - P01589 REA ) , 100 received basiliximab and delayed tacrolimus ( dTAC - P01589 REA ) , and 132 patients received tacrolimus without basiliximab ( TAC-No ) . The endpoints were the incidence of acute rejection , graft function , and patient and graft survivals at 1 year . RESULTS : The incidence of acute rejection was higher in dTAC - P01589 REA compared to TAC-IL - 2RA and TAC-No Groups ( 33 vs . 14.9 vs . 14.3 % , p < 0.001 ) . Inferior creatinine clearance was observed in dTAC - P01589 REA Group compared to TAC - P01589 REA and TAC-No Groups at months 1 ( 41.6 vs . 49.9 vs . 44.8 mL / min , p = 0.004 ) , 3 ( 49.8 vs . 57.2 vs . 53.5 mL / min , p = 0.017 ) , and 6 ( 53.1 vs . 61.8 vs . 57.0 mL / min , p = 0.001 ) . Patients who received basiliximab ( TAC - P01589 REA and dTAC - P01589 REA Groups ) had lower incidence of posttransplant diabetes ( 24 vs . 18 vs . 39.3 % , p = 0.009 ) . Patient and graft survivals were similar among the groups . CONCLUSIONS : In low immunological risk kidney transplant recipients receiving tacrolimus , the use of basiliximab induction was not associated with lower rejection rates and did not allow delayed tacrolimus introduction .

Electrostatic steering at acetylcholine binding sites . The electrostatic environments near the acetylcholine binding sites on the nicotinic acetylcholine receptor ( nAChR ) and acetylcholinesterase were measured by diffusion-enhanced fluorescence energy transfer ( DEFET ) to determine the influence of long-range electrostatic interactions on ligand binding kinetics and net binding energy . Changes in DEFET from variously charged Tb3 + - chelates revealed net potentials of - 20 mV at the nAChR agonist sites and - 14 mV at the entrance to the P22303 REA active site , in physiological ionic strength conditions . The potential at the alphadelta-binding site of the nAChR was determined independently in the presence of DB01199 MEN to be - 14 mV ; the calculated potential at the alphagamma-site was approximately threefold stronger than at the alphadelta-site . By determining the local potential in increasing ionic strength , Debye-Hückel theory predicted that the potentials near the nAChR agonist binding sites are constituted by one to three charges in close proximity to the binding site . Examination of the binding kinetics of the fluorescent acetylcholine analog dansyl - P13671 REA - choline at ionic strengths from 12.5 to 400 mM revealed a twofold decrease in association rate . Debye-Hückel analysis of the kinetics revealed a similar charge distribution as seen by changes in the potentials . To determine whether the experimentally determined potentials are reflected by continuum electrostatics calculations , solutions to the nonlinear Poisson-Boltzmann equation were used to compute the potentials expected from DEFET measurements from high-resolution models of the nAChR and P22303 REA . These calculations are in good agreement with the DEFET measurements for P22303 REA and for the alphagamma-site of the nAChR . We conclude that long-range electrostatic interactions contribute -0.3 and - 1 kcal / mol to the binding energy at the nAChR alphadelta - and alphagamma-sites due to an increase in association rates .

P25874 REA - mediated free fatty acid uncoupling of isolated cortical mitochondria from fasted animals : correlations to dietary modulations . Uncoupling proteins ( P25874 REA ) translocate protons from the mitochondrial intermembrane space to the matrix , thereby " uncoupling " electron transport from the production of DB00171 . It has been shown that these proteins are highly expressed in animals maintained on the ketogenic diet ( KD ) . Although the exact mechanism remains unclear , it is known that these proteins are activated within a protective antireactive oxygen species ( ROS ) mechanism by free fatty acids ( FFA ) . In our current studies , mitochondrial samples were probed for the presence of P55851 REA , which is the most ubiquitously expressed P25874 REA isoform . We found that both traumatic brain injury and fasting upregulated the expression of P55851 REA , with a synergistic upregulation in fasted injured animals . We then used mitochondria from fasted naive animals to screen a number of FFA for their activation of uncoupling as well as their ability to reduce ROS . We found that arachidonic acid ( AA ) , docosahexaenoic acid ( DB01708 ) , eicosapentaenoic acid ( EPA ) , palmitoleic acid , myristic acid , and butyric acid increased mitochondrial uncoupling when added after oligomycin . These FFA , along with oleic acid , also reduced ROS in mitochondria incubated with oligomycin . In order to correlate our data to KD and fasting , both of which have been shown to be neuroprotective after neurologic insult , we determined the serum levels of FFA in KD and fasted animals using gas chromatography / mass spectroscopy . We also determined brain and cerebrospinal fluid ( P04141 REA ) FFA levels from fasted animals .

Molecular mechanisms of patupilone resistance . DB03010 MEN is an epothilone in advanced clinical development that has shown promising efficacy in heavily pretreated patients . This study aimed at characterizing the mechanisms of patupilone activity in resistant patients . To this end , we generated patupilone-resistant cells using two cellular models , the first characterized by high chemosensitivity and low class III beta-tubulin ( Q13509 REA ) expression ( A2780 ) , and the second by low chemosensitivity and high Q13509 REA expression ( OVCAR - 3 ) . The obtained cell lines were named EPO 3 and OVCAR-EPO , respectively . The same selection procedure was done in A2780 cells to generate a paclitaxel-resistant cell line ( TAX 50 ) . Factors of resistance are expected to increase in the drug-resistant cell lines , whereas factors of drug sensitivity will be down-regulated . Using this approach , we found up-regulation of Q13509 REA in TAX 50 , but not EPO 3 , cells , showing that Q13509 REA mediates the resistance to paclitaxel but not to patupilone . Moreover , Q13509 REA was a factor of patupilone sensitivity because OVCAR-EPO cells exhibited a dramatic reduction of Q13509 REA and a concomitant sensitization to hypoxia and cisplatin-based chemotherapy . To identify the mechanisms underlying patupilone resistance , tubulin genes were sequenced , thereby revealing that a prominent mechanism of drug resistance is represented by point mutations in class I beta-tubulin . Overall , these results suggest that paclitaxel and patupilone have nonoverlapping mechanisms of resistance , thus allowing the use of patupilone for those patients relapsing after paclitaxel-based chemotherapy . Furthermore , patupilone represents a promising first-line option for the treatment of high-risk ovarian cancer patients , who exhibit high Q13509 REA levels and poor response to standard paclitaxel-platin chemotherapy .

P11274 REA - P00519 REA suppresses C / EBPalpha expression through inhibitory action of Q15366 REA . The arrest of differentiation is a feature of both chronic myelogenous leukemia cells in myeloid blast crisis and myeloid precursors that ectopically express the p210BCR - P00519 REA oncoprotein ; however , its underlying mechanisms remain poorly understood . Here we show that expression of P11274 REA - P00519 REA in myeloid precursor cells leads to transcriptional suppression of the granulocyte colony-stimulating factor receptor Q99062 REA ( encoded by Q99062 REA ) , possibly through down-modulation of C / EBPalpha-the principal regulator of granulocytic differentiation . Expression of C / EBPalpha protein is barely detectable in primary marrow cells taken from individuals affected with chronic myeloid leukemia in blast crisis . In contrast , P49715 REA RNA is clearly present . Ectopic expression of C / EBPalpha induces granulocytic differentiation of myeloid precursor cells expressing P11274 REA - P00519 REA . Expression of C / EBPalpha is suppressed at the translational level by interaction of the poly ( rC ) - binding protein Q15366 REA with P49715 REA mRNA , and ectopic expression of Q15366 REA in myeloid precursor cells down-regulates both C / EBPalpha and Q99062 REA and leads to rapid cell death on treatment with DB00099 MEN ( encoded by P09919 REA ) . Our results indicate that P11274 REA - P00519 REA regulates the expression of C / EBPalpha by inducing Q15366 REA - which inhibits the translation of P49715 REA mRNA .

Q9HBE4 signalling via P40763 REA primes human naive B cells to respond to P60568 REA to enhance their differentiation into plasmablasts . B-cell responses are guided by the integration of signals through the B-cell receptor ( P11274 REA ) , P25942 REA , and cytokine receptors . The common γ chain ( γc ) - binding cytokine interleukin ( IL ) - 21 drives humoral immune responses via P40763 REA - dependent induction of transcription factors required for plasma cell generation . We investigated additional mechanisms by which Q9HBE4 / P40763 REA signaling modulates human B-cell responses by studying patients with P40763 REA mutations . Q9HBE4 strongly induced CD25 ( IL - 2Rα ) in normal , but not P40763 REA - deficient , P29965 REA - stimulated naïve B cells . Chromatin immunoprecipitation confirmed P01589 REA as a direct target of P40763 REA . Q9HBE4 - induced CD25 expression was also impaired on B cells from patients with P31785 REA or Q9HBE5 mutations , confirming a requirement for intact Q9HBE5 signaling in this process . P60568 REA increased plasmablast generation and immunoglobulin secretion from normal , but not CD25 - deficient , naïve B cells stimulated with P29965 REA / Q9HBE4 . P60568 REA and Q9HBE4 were produced by T follicular helper cells , and neutralizing both cytokines abolished the B-cell helper capacity of these cells . Our results demonstrate that Q9HBE4 , via P40763 REA , sensitizes B cells to the stimulatory effects of P60568 REA . Thus , P60568 REA may play an adjunctive role in Q9HBE4 - induced B-cell differentiation . Lack of this secondary effect of Q9HBE4 may amplify the humoral immunodeficiency in patients with mutations in P40763 REA , P31785 REA , or Q9HBE5 due to impaired responsiveness to Q9HBE4 .

Mobilization of Ph chromosome-negative peripheral blood stem cells in chronic myeloid leukaemia patients with imatinib mesylate-induced complete cytogenetic remission . Imatinib mesylate ( IM , DB00619 SUB , Glivec ) can induce a high rate of complete cytogenetic response ( CCR ) in chronic myeloid leukaemia ( CML ) patients , although to date the majority of patients continue to have detectable disease by sensitive reverse transcription polymerase chain reaction ( RT-PCR ) . It is therefore possible that these patients may ultimately relapse and require treatment such as autologous peripheral blood stem cell transplant ( APBSCT ) . We attempted mobilization of haemopoietic progenitor cells from 58 patients in CCR using recombinant human granulocyte colony-stimulating factor [ rHu - DB00099 MEN ; 10 micro g / kg / d subcutaneously ( s . c . ) for at least 4 d ] alone , while continuing IM treatment . The median d 5 ( peak ) P28906 REA + count was 11.5 / microl ( range 0-108 / microl ) , and 43/58 ( 74 % ) patients underwent a median of two ( range 1-3 ) apheresis procedures . A median dose of 2.1 x 10 ( 6 ) / kg P28906 REA + cells ( range 0.1- 6.5 x 10 ( 6 ) / kg ) was collected . Some 84 % of 31 collections analysed were negative for the Philadelphia ( Ph ) chromosome or breakpoint cluster region and Abelson murine leukaemia viral oncogene homologue ( P11274 REA - P00519 REA ) translocation by cytogenetics or fluorescent in situ hybridization respectively . No toxicity was reported with the regimen . Overall , the target P28906 REA + dose ( 2 x 10 ( 6 ) / kg P28906 REA + ) was attained in 23/58 ( 40 % ) patients who entered the study . In summary , we have demonstrated that successful mobilization of Ph - P28906 REA + cells from IM-treated patients in CCR is possible using rHu-G - P04141 REA alone .

DB02426 MEN effects on brown-fat mitochondria imply that the adenine nucleotide translocator isoforms P12235 REA and P05141 REA may be responsible for basal and fatty-acid-induced uncoupling respectively . In brown-fat mitochondria , fatty acids induce thermogenic uncoupling through activation of P25874 REA ( uncoupling protein 1 ) . However , even in brown-fat mitochondria from P25874 REA - / - mice , fatty-acid-induced uncoupling exists . In the present investigation , we used the inhibitor CAtr ( carboxyatractyloside ) to examine the involvement of the ANT ( adenine nucleotide translocator ) in the mediation of this P25874 REA - independent fatty-acid-induced uncoupling in brown-fat mitochondria . We found that the contribution of ANT to fatty-acid-induced uncoupling in P25874 REA - / - brown-fat mitochondria was minimal ( whereas it was responsible for nearly half the fatty-acid-induced uncoupling in liver mitochondria ) . As compared with liver mitochondria , brown-fat mitochondria exhibit a relatively high ( P25874 REA - independent ) basal respiration ( ' proton leak ' ) . Unexpectedly , a large fraction of this high basal respiration was sensitive to CAtr , whereas in liver mitochondria , basal respiration was CAtr-insensitive . Total ANT protein levels were similar in brown-fat mitochondria from wild-type mice and in liver mitochondria , but the level was increased in brown-fat mitochondria from P25874 REA - / - mice . However , in liver , only Ant 2 mRNA was found , whereas in brown adipose tissue , Ant 1 and Ant 2 mRNA levels were equal . The data are therefore compatible with a tentative model in which the P05141 REA isoform mediates fatty-acid-induced uncoupling , whereas the P12235 REA isoform may mediate a significant part of the high basal proton leak in brown-fat mitochondria .

DB06643 MENMAX DB06643 MEN in postmenopausal osteoporosis : what the clinician needs to know . DB06643 MEN is a subcutaneously ( SC ) administered investigational fully human monoclonal antibody to receptor activator of nuclear factor-kB ligand ( O14788 REA ) , a cytokine member of the tumor necrosis factor family that is the principal mediator of osteoclastic bone resorption . O14788 REA stimulates the formation , activity , and survival of osteoclasts , and is implicated in the pathogenesis of postmenopausal osteoporosis and other skeletal disorders associated with increased bone remodeling . DB06643 MEN binds O14788 REA , preventing it from binding to Q9Y6Q6 REA , thereby reducing the formation , activity , and survival of osteoclasts and slowing the rate of bone resorption . Postmenopausal women with low bone mineral density ( BMD ) treated with denosumab have a reduction of bone turnover markers and an increase in BMD that is rapid , sustained , and reversible . In postmenopausal women with osteoporosis , denosumab reduces the risk of vertebral , hip , and nonvertebral fractures . In postmenopausal women with low BMD randomized to receive denosumab or alendronate , denosumab is associated with a significantly greater increase in BMD and further reduction in bone turnover markers compared with alendronate . In postmenopausal women with low BMD who were previously treated with alendronate , those who switched to denosumab have a significantly greater BMD increase and further reduction in bone turnover markers compared with those continuing alendronate . DB06643 MEN is well tolerated with a favorable safety profile . It is a promising emerging drug for the prevention and treatment of osteoporosis , offering a long dosing interval of every 6 months and convenient SC dosing , with the potential of improving long-term adherence to therapy compared with current oral treatments .

Update on the biology and therapy of gastrointestinal stromal tumors . BACKGROUND : Gastrointestinal stromal tumors ( GISTs ) , the most common mesenchymal tumors of the gastrointestinal tract , are an example of a disease with an effective , molecularly targeted therapy . METHODS : Published articles and author experience were used to comprehensively define the clinical features , biology , and state-of-the-art therapy of GISTs . RESULTS : GISTs are thought to originate from the neoplastic transformation of the interstitial cells of Cajal , the intestinal pacemaker cells . GISTs commonly have mutations in the kit gene , resulting in a gain-of-function mutation and ligand-independent constitutive activation of the P10721 REA receptor tyrosine kinase . Successful tyrosine kinase inhibitors target the aberrant pathways that are critical for tumor cell viability . The development of imatinib mesylate ( formerly DB00619 SUB ) in the treatment of metastatic GISTs represents a therapeutic breakthrough . CONCLUSIONS : Progress in the clinical diagnosis has led to an increased recognition of this disease as a distinct clinical entity . Treatment of metastatic GIST with imatinib has led to unprecedented improvements in progression-free and overall survival . The use of imatinib in the preoperative and postoperative treatment of GISTs is an area of intense investigation .

Delineation of gastric cancer subtypes by co-regulated expression of receptor tyrosine kinases and chemosensitivity genes . Chemotherapy plays a key role in improving disease-free survival and overall survival of gastric cancer ( GC ) ; however , response rates are variable and a non-negligible proportion of patients undergo toxic and costly chemotherapeutic regimens without a survival benefit . Several studies have shown the existence of GC subtypes which may predict survival and respond differently to chemotherapy . It is also known that the expression level of chemotherapy-related and target therapy-related genes correlates with response to specific antitumor drugs . Nevertheless , these genes have not been considered jointly to define GC subtypes . In this study , we evaluated seven genes known to influence chemotherapeutic response ( P07992 REA , P38398 REA , P23921 REA , Q13509 REA , P16949 REA , P04818 REA and P11388 REA ) and five receptor tyrosine kinases ( RTKs ) ( P00533 REA , P04626 REA , P09619 REA , P17948 REA and P35968 REA ) . We demonstrate significant heterogeneity of gene expression among GC patients and identified four GC subtypes using the expression profiles of eight genes in two co-regulation groups : chemosensitivity ( P38398 REA , P16949 REA , P04818 REA and P11388 REA ) and RTKs ( P00533 REA , P09619 REA , P17948 REA and P35968 REA ) . The results are of immediate translational value regarding GC diagnostics and therapeutics , as many of these genes are curently widely used in relevant clinical testing .

The role of the granulocyte colony-stimulating factor receptor ( Q99062 REA ) in disease . P09919 REA ( DB00099 MEN ) is a key regulator of granulopoiesis via stimulation of a specific cell-surface receptor , the Q99062 REA , found on hematopoietic progenitor cells as well as neutrophilic granulocytes . It is perhaps not surprising , therefore , that mutations of the Q99062 REA has been implicated in several clinical settings that affect granulocytic differentiation , particularly severe congenital neutropenia , myelodysplastic syndrome and acute myeloid leukemia . However , other studies suggest that signalling via the Q99062 REA is also involved in a range of other malignancies . This review focuses on the molecular mechanisms through which the Q99062 REA contributes to disease .

Critical role of P21453 REA and integrin β4 in P14210 REA / c - DB00134 - mediated increases in vascular integrity . Vascular endothelial cell ( EC ) barrier integrity is critical to vessel homeostasis whereas barrier dysfunction is a key feature of inflammatory disorders and tumor angiogenesis . We previously reported that hepatocyte growth factor ( P14210 REA ) - mediated increases in EC barrier integrity are signaled through a dynamic complex present in lipid rafts involving its receptor , c - DB00134 . We extended these observations to confirm that P21453 REA ( sphingosine 1 - phosphate receptor 1 ) and integrin β4 ( P16144 REA ) are essential participants in P14210 REA - induced EC barrier enhancement . Immunoprecipitation experiments demonstrated P14210 REA - mediated recruitment of c - DB00134 , P16144 REA and P21453 REA to caveolin-enriched lipid rafts in human lung EC with direct interactions of c - DB00134 with both P21453 REA and P16144 REA accompanied by c - DB00134 - dependent P21453 REA and P16144 REA transactivation . Reduced P21453 REA expression ( siRNA ) attenuated both P16144 REA and Rac 1 activation as well as c - DB00134 / P16144 REA interaction and resulted in decreased transendothelial electrical resistance . Furthermore , reduced P16144 REA expression attenuated P14210 REA - induced c - DB00134 activation , c - DB00134 / P21453 REA interaction , and effected decreases in Q14703 REA - and P14210 REA - induced EC barrier enhancement . Finally , the c - DB00134 inhibitor , DB05030 MEN , suppressed P14210 REA - induced c - DB00134 activation as well as P21453 REA and P16144 REA transactivation . These results support a critical role for P21453 REA and P16144 REA transactivation as rate-limiting events in the transduction of P14210 REA signals via a dynamic c - DB00134 complex resulting in enhanced EC barrier integrity .

Polyamines and membrane transporters . In recent years , our understanding of the importance of membrane transporters ( MTs ) in the disposition of and response to drugs has increased significantly . MTs are proteins that regulate the transport of endogenous molecules and xenobiotics across the cell membrane . In mammals , two super-families have been identified : DB00171 - binding cassette ( DB01048 ) and solute carrier ( O00585 REA ) transporters . There is evidence that MTs might mediate polyamines ( PA ) transport . PA are ubiquitous polycations which are found in all living cells . In mammalian cells , three major PA are synthesised : putrescine , spermidine and spermine ; whilst the decarboxylated arginine ( agmatine ) is not produced by mammals but is synthesised by plants and bacteria . In addition , research in the PA field suggests that PA are transported into cells via a specific transporter , the polyamine transport system ( s ) ( Q03393 REA ) . Although the Q03393 REA has not been fully defined , there is evidence that some of the known MTs might be involved in PA transport . In this mini review , eight O00585 REA transporters will be reviewed and their potential to mediate PA transport in human cells discussed . These transporters are O15245 REA , O15244 REA , O75751 REA , Q96FL8 , P30825 REA , P08195 REA , SLC 12A8A , and Q86VW1 . Preliminary data from our laboratory have revealed that O15245 REA might be involved in the PA uptake ; in addition to one member of ABC superfamily ( P08183 REA protein ) might also mediate the efflux of polyamine like molecules .

Imatinib mesylate ( Gleevec ) enhances mature osteoclast apoptosis and suppresses osteoclast bone resorbing activity . Recent studies have reported that imatinib mesylate , a kinase inhibitor that targets the intracellular tyrosine kinase P11274 REA - P00519 REA and the platelet derived growth factor ( PDGF ) receptor , is an effective inhibitor of the macrophage colony stimulating factor ( P09603 REA ) receptor , c - P07333 REA . Given that P09603 REA signalling through c - P07333 REA plays an important role in osteoclast biology , we speculated that blocking such a pathway with imatinib may modulate osteoclast activity . Using a cell model of mature rabbit osteoclasts , we thus investigated the effect of imatinib on in vitro osteoclast apoptosis and bone resorbing activity . Our findings demonstrate that imatinib dose-dependently stimulates osteoclast apoptosis , a phenomenon which is blocked by the caspase I inhibitor Z-VAD-fmk . The ability of imatinib to enhance osteoclast cell death was accompanied by a dose-dependent inhibition of osteoclast bone resorbing activity . Imatinib was also found to inhibit P09603 REA - induced osteoclast survival as well as P09603 REA - induced osteoclast bone resorbing activity , but was without effect on interleukin 1alpha ( IL - 1alpha ) and receptor activator of nuclear factor kappa B ligand ( O14788 REA ) - induced inhibition of osteoclasts apoptosis , further supporting the hypothesis that imatinib may affect mature osteoclasts through the inhibition of c - P07333 REA . Taken together , these results suggest that imatinib could be of clinical value in treating diseases where bone destruction can occur due to excessive P09603 REA production such as osteoporosis , inflammatory-and tumor-induced osteolysis .

Inhibition of P08183 REA does not sensitize primitive chronic myeloid leukemia P28906 REA + cells to imatinib . OBJECTIVE : To investigate the interaction of imatinib mesylate ( IM ) with the clinically relevant adenosine triphosphate-binding cassette efflux transporter P08183 REA ( P08183 REA ) in cells from patients with chronic myeloid leukemia ( CML ) and to explore whether inhibition of this transporter would improve IM ' s efficacy in the elimination of CML P28906 REA ( + ) cells by increasing cell-associated drug accumulation . MATERIALS AND METHODS : Cells from newly diagnosed chronic-phase CML patients were harvested by leukapheresis and enriched to > 95 % P28906 REA ( + ) . Expression of the transporter gene P08183 REA was performed by quantitative reverse transcription polymerase chain reaction . Interaction of IM with P08183 REA was analyzed by substrate ( rhodamine 123 ) displacement assay . Cell-associated levels of IM in CML P28906 REA ( + ) cells were measured by high-pressure liquid chromatography . Intracellular phospho-CrkL levels , apoptosis in total CML P28906 REA ( + ) cells and high-resolution tracking of cell division were assayed by flow cytometry . RESULTS : Measurements of cell-associated IM uptake showed significantly lower drug levels in P28906 REA ( + ) cells , particularly the P28907 REA ( - ) subpopulation , as compared to IM-sensitive K562 cells . P08183 REA was expressed at low level and dye efflux studies demonstrated very little P08183 REA activity in CML P28906 REA ( + ) cells . Furthermore , combination treatment of primitive CML cells with IM and the P08183 REA inhibitor PSC 833 did not result in elevated cell-associated IM levels . Although we observed slightly enhanced cytostasis with IM when combined with PSC 833 , this was independent of P11274 REA - P00519 REA inhibition because no associated decrease in phospho-CrkL was observed . CONCLUSIONS : Our findings demonstrate that inhibition of P08183 REA neither enhances the effect of IM against P11274 REA - P00519 REA activity , nor significantly potentiates IM ' s efficiency in eliminating primitive CML cells .

[ Signal transduction inhibitor - - STI 571 - - a new treatment for chronic myeloid leukemia ( CML ) , which opens a new targeted approach to cancer therapy ] . Chronic myeloid leukemia ( CML ) , in most of the cases , is the molecular consequence of the t ( 9,22 ) translocation , resulting in the Philadelphia ( Ph ) chromosome and the creation of the fusion gene P11274 REA - P00519 REA . The fusion gene is translated to the protooncogen P11274 REA - P00519 REA , a constitutively activated tyrosine kinase that is linked to the malignant transformation . Thus , this tyrosine kinase became an attractive target for drug design . The development of the novel investigational drug DB00619 SUB is based on its potent and selective ability to inhibit this fusion tyrosine kinase . In preclinical studies , DB00619 SUB selectively inhibited the growth of CML cells that carry the Ph chromosome . In this review we discuss the drug development and design , its mechanism of action , the preclinical studies and the results of phase I and II clinical trials .