MH_dev_79

Purification and characterization of a high molecular weight histone deacetylase complex ( Q92769 REA ) of maize embryos . The dynamic state of core histone acetylation is maintained by histone acetyltransferases and deacetylases . In germinating maize embryos , four nuclear histone deacetylases can be distinguished . From a chromatin fraction prepared at 72 h after start of embryo germination , we have purified the nuclear histone deacetylase Q92769 REA to homogeneity . Using a sequence of chromatographic steps , we achieved the purification of an enzymatically active high molecular weight protein complex with an apparent molecular mass of 400 kDa , as determined by gel filtration chromatography . The purified enzyme was characterized in terms of enzymatic and kinetic properties , and sensitivity to several histone deacetylase inhibitors . In SDS-polyacrylamide gels , Q92769 REA split into three polypeptides of 45 , 42 , and 39 kDa , suggesting that the native enzyme is a multimer-protein complex . Electrophoresis under nondenaturing conditions in combination with second dimension SDS-gel electrophoresis indicated that all three protein components of the Q92769 REA complex were enzymatically active . Polyclonal antibodies against each of the three polypeptides were raised in rabbits . Each antiserum reacted with all three polypeptides on Western blots , suggesting that P29466 REA , Q8NFH3 , and p39 are highly homologous . This homology was confirmed by amino acid sequencing of peptides generated from each of the three Q92769 REA components .

DB06288 SUB is a potent P34969 REA antagonist : relevance for antidepressant actions in vivo . RATIONALE : DB06288 SUB is approved for clinical use in treating schizophrenia in a number of European countries and also for treating dysthymia , a mild form of depression , in Italy . DB06288 SUB has also been demonstrated to be an antidepressant for patients with major depression in many clinical trials . In part because of the selective D ( 2 ) / D ( 3 ) receptor antagonist properties of amisulpride , it has long been widely assumed that dopaminergic modulation is the proximal event responsible for mediating its antidepressant and antipsychotic properties . OBJECTIVES : The purpose of these studies was to determine if amisulpride ' s antidepressant actions are mediated by off-target interactions with other receptors . MATERIALS AND METHODS : We performed experiments that : ( 1 ) examined the pharmacological profile of amisulpride at a large number of central nervous system ( CNS ) molecular targets and , ( 2 ) after finding high potency antagonist affinity for human 5 - HT ( 7a ) serotonin receptors , characterized the actions of amisulpride as an antidepressant in wild-type and 5 - HT ( 7 ) receptor knockout mice . RESULTS : We discovered that amisulpride was a potent competitive antagonist at 5 - HT ( 7a ) receptors and that interactions with no other molecular target investigated in this paper could explain its antidepressant actions in vivo . Significantly , and in contrast to their wild-type littermates , 5 - HT ( 7 ) receptor knockout mice did not respond to amisulpride in two widely used rodent models of depression , the tail suspension test and the forced swim test . CONCLUSIONS : These results indicate that 5 - HT ( 7a ) receptor antagonism , and not D ( 2 ) / D ( 3 ) receptor antagonism , likely underlies the antidepressant actions of amisulpride .

Serotonin and vasopressin interact in the hypothalamus to control communicative behavior . The present study investigated whether serotonin ( 5 - HT ) agonists could inhibit the ability of arginine-vasopressin ( AVP ) to induce a form of scent marking called flank marking by their actions in the medial preoptic-anterior hypothalamus ( MPOA-AH ) . DOI , a 5 - Q13049 REA , 2B , 2C receptor agonist , did not inhibit AVP-induced flank marking , but mCPP a 5 - Q13049 REA antagonist and P41595 REA , 2C agonist inhibited AVP-induced flank marking . In addition , the finding that 8 - OH-DPAT , CGS - 12066A and SC53116 also inhibited AVP-induced flank marking suggests that 5 - HT could also inhibit flank marking by acting through P08908 REA , P34969 REA , P28222 REA and / or Q13639 REA receptor subtypes . These data support the hypothesis that 5 - HT acts within the MPOA-AH to inhibit the ability of AVP to induce flank marking .

Serotonin via P34969 REA receptors activates p38 mitogen-activated protein kinase and protein kinase C epsilon resulting in interleukin - 6 synthesis in human U373 MG astrocytoma cells . Serotonin [ 5 - hydroxytryptamine ( 5 - HT ) ] is a widely distributed neurotransmitter which is involved in neuroimmunomodulatory processes . Previously , it has been demonstrated that 5 - HT may induce interleukin ( IL ) - 6 expression in primary rat hippocampal astrocytes . The present study was undertaken to investigate the molecular pathways underlying this induction of P05231 REA synthesis . As a model system , we used the human astrocytoma cell line U373 MG , which synthesizes P05231 REA upon stimulation with various inducers . 5 - HT dose - and time-dependently induced P05231 REA protein synthesis . We identified several 5 - HT receptors to be expressed on U373 MG cells , including the P28221 REA , 5 - Q13049 REA , 5 - Q9H205 REA and P34969 REA receptors . In this report , we show that the 5 - HT-induced P05231 REA release is mediated by the P34969 REA receptor based on several agonist / antagonists that were used . 5 - HT-induced P05231 REA synthesis is inhibited by the partially selective P34969 REA receptor antagonist , pimozide , and the selective antagonist SB269970 . Furthermore , P05231 REA synthesis was induced by the P34969 REA receptor agonist carboxamidotryptamin . In addition , we found p38 MAPKs and protein kinase C ( PKC ) epsilon to be involved in 5 - HT-induced P05231 REA synthesis as specific inhibitors of these enzymes ( SB202190 and RO -31-8425 , respectively ) blocked 5 - HT-induced P05231 REA synthesis . Furthermore , 5 - HT mediated the phosphorylation of both p38 MAPK as well as the PKC epsilon isoform . The Q8NFH3 / 44 MAPKs , however , were not involved in 5 - HT-induced P05231 REA synthesis . This study shows , for the first time , a central role of P34969 REA receptor linked to p38 MAPK and PKC epsilon for the induction of cytokine synthesis in astrocytic cells .

Variants of dopamine and serotonin candidate genes as predictors of response to risperidone treatment in first-episode schizophrenia . AIMS : Abnormalities in dopaminergic and serotonergic transmission systems are thought to be involved in the pathophysiology of schizophrenia and the mechanisms underlying the therapeutic effects of antipsychotics . We conducted a pharmacogenetic study to evaluate whether variants in dopamine-related genes ( P21728 REA - P21918 REA , P31749 REA and GSK 3beta ) and serotonin receptor genes ( P08908 REA , P28222 REA , P28221 REA , P28223 REA , P28335 REA , P50406 REA and P34969 REA ) can be used to predict the efficacy of risperidone treatment for schizophrenia . MATERIALS & METHODS : A total of 120 first-episode neuroleptic-naive schizophrenia patients were treated with risperidone monotherapy for 8 weeks and clinical symptoms were evaluated by the Positive and Negative Syndrome Scale . RESULTS : Among the 30 variants that we examined , two SNPs in P14416 REA ( - 241A > G [ rs1799978 ] and TaqIA [ rs1800497 ] ) and two SNPs in P31749 REA ( P31749 REA - SNP 1 [ rs3803300 ] and P31749 REA - SNP 5 [ rs2494732 ] ) were significant predictors of treatment response to risperidone . CONCLUSION : These data suggest that the SNPs in P14416 REA and P31749 REA may influence the treatment response to risperidone in schizophrenia patients .

Clot penetration and retention by plasminogen activators promote fibrinolysis . P00750 REA ( tPA ) remains the sole thrombolytic approved by the FDA for the treatment of pulmonary embolism ( PE ) . tPA has not been replaced by third generation plasminogen activators , e . g . DB00015 ( Ret ) and DB00031 MEN ( TNK ) that circulate with longer life-spans and in theory should have more extended potency in vivo . One reason for this paradox is the inability to assign units of activity to plasminogen activators based on specific biologically relevant standards , which impairs objective comparison . Here , we compare clot permeation , retention and fibrinolytic activities of tPA , TNK and Ret in vitro and clot composition over time with outcome in a mouse model of disseminated pulmonary microembolism ( ME ) . When clots were incubated in the continuous presence of drug , tPA , TNK and Ret lysed fibrin clots identically in the absence of PA inhibitor - 1 ( e . g . P05121 REA ) . Ret , which has lower fibrin affinity and greater susceptibility to inhibition by P05121 REA than tPA , was less effective in lysing plasma clots , while TNK was less effective when the fibrin content of the clots was enhanced . However , when clots were afforded only brief exposure to drug , as occurs in vivo , Ret showed more extensive clot permeation , greater retention and lysis than tPA or TNK . These results were reproduced in vivo in a mouse model of ME . These studies indicate the need for more relevant tests of plasminogen activator activity in vitro and in vivo and they show that clot permeation and retention are important potential predictors of clinical utility .

Targeting Q01196 REA / Q06455 - histone deacetylase repressor complex : a novel mechanism for valproic acid-mediated gene expression and cellular differentiation in Q01196 REA / Q06455 - positive acute myeloid leukemia cells . In t (8 ; 21 ) acute myeloid leukemia ( AML ) , the Q01196 REA / Q06455 fusion protein promotes leukemogenesis by recruiting class I histone deacetylase ( HDAC ) - containing repressor complex to the promoter of Q01196 REA target genes . Valproic acid ( DB00313 MEN ) , a commonly used antiseizure and mood stabilizer drug , has been shown to cause growth arrest and induce differentiation of malignant cells via HDAC inhibition . DB00313 MEN causes selective proteasomal degradation of Q92769 REA but not other class I HDACs ( i . e . , HDAC 1 , 3 , and 8 ) . Therefore , we raised the question of whether this drug can effectively target the leukemogenic activity of the Q01196 REA / Q06455 fusion protein that also recruits Q13547 REA , a key regulator of normal and aberrant histone acetylation . We report here that DB00313 MEN treatment disrupts the Q01196 REA / Q06455 - Q13547 REA physical interaction , stimulates the global dissociation of Q01196 REA / Q06455 - Q13547 REA complex from the promoter of Q01196 REA / Q06455 target genes , and induces relocation of both Q01196 REA / Q06455 and Q13547 REA protein from nuclear to perinuclear region . Furthermore , we show that mechanistically these effects associate with a significant inhibition of HDAC activity , histone H3 and H4 hyperacetylation , and recruitment of RNA polymerase II , leading to transcriptional reactivation of target genes ( i . e . , P08700 REA ) otherwise silenced by Q01196 REA / Q06455 fusion protein . Ultimately , these pharmacological effects resulted in significant antileukemic activity mediated by partial cell differentiation and caspase-dependent apoptosis . Taken together , these data support the notion that DB00313 MEN might effectively target Q01196 REA / Q06455 - driven leukemogenesis through disruption of aberrant Q13547 REA function and that DB00313 MEN should be integrated in novel therapeutic approaches for Q01196 REA / Q06455 - positive AML .

Serotonin skews human macrophage polarization through P41595 REA and P34969 REA . Besides its role as a neurotransmitter , serotonin ( 5 - hydroxytryptamine , 5HT ) regulates inflammation and tissue repair via a set of receptors ( 5HT ( 1-7 ) ) whose pattern of expression varies among cell lineages . Considering the importance of macrophage polarization plasticity for inflammatory responses and tissue repair , we evaluated whether 5HT modulates human macrophage polarization . 5HT inhibited the LPS-induced release of proinflammatory cytokines without affecting P22301 REA production , upregulated the expression of M2 polarization-associated genes ( P05120 REA , P07996 REA , Q9NY15 , Q86Y22 REA ) , and reduced the expression of M1 - associated genes ( P08476 REA , P41597 REA , P39900 REA , P05121 REA , P29016 REA , O94788 REA ) . Whereas only 5HT ( 7 ) mediated the inhibitory action of 5HT on the release of proinflammatory cytokines , both 5HT ( 2B ) and 5HT ( 7 ) receptors mediated the pro-M 2 skewing effect of 5HT . In fact , blockade of both receptors during in vitro monocyte-to-macrophage differentiation preferentially modulated the acquisition of M2 polarization markers . 5HT ( 2B ) was found to be preferentially expressed by anti-inflammatory M2 ( P09603 REA ) macrophages and was detected in vivo in liver Kupffer cells and in tumor-associated macrophages . Therefore , 5HT modulates macrophage polarization and contributes to the maintenance of an anti-inflammatory state via 5HT ( 2B ) and 5HT ( 7 ) , whose identification as functionally relevant markers for anti-inflammatory / homeostatic human M2 macrophages suggests their potential therapeutic value in inflammatory pathologies .

DB06288 SUB promotes cognitive flexibility in rats : the role of P34969 REA receptors . The antagonism of P34969 REA receptors may contribute to the antidepressant and procognitive actions of the atypical antipsychotic drug , amisulpride . It has been previously demonstrated that the selective P34969 REA receptor antagonist reversed restraint stress-induced cognitive impairments in a rat model of frontal-dependent attentional set-shifting task ( ASST ) . Therefore , the first aim of the present study was to assess the effectiveness of amisulpride against stress-evoked cognitive inflexibility . The second goal was to elucidate whether the pro-cognitive effect of amisulpride could be due to the compound ' s action at P34969 REA receptors . Rats repeatedly exposed ( 1 h daily for 7 days ) to restraint stress demonstrated impaired performance on the extra-dimensional ( ED ) set-shifting stage of the ASST . DB06288 SUB ( 3 mg / kg ) given to stressed rats 30 min before testing reversed this restraint-induced cognitive inflexibility and improved ED performance of the unstressed control group . The P34969 REA receptor agonist , AS19 ( 10 mg / kg ) , abolished the pro-cognitive efficacy of amisulpride ( 3 mg / kg ) . The present study suggests that the antagonism of P34969 REA receptors may contribute to the mechanisms underlining the pro-cognitive action of amisulpride . These results may have therapeutic implications in frontal-like deficits associated with stress-related disorders .

Activation of telomerase by ionizing radiation : differential response to the inhibition of DNA double-strand break repair by abrogation of poly ( ADP-ribosyl ) ation , by LY294002 , or by Wortmannin . PURPOSE : Telomerase activity represents a radiation-inducible function , which may be targeted by a double-strand break ( DSB ) - activated signal transduction pathway . Therefore , the effects of DNA-PK inhibitors ( Wortmannin and LY294002 ) on telomerase upregulation after irradiation were studied . In addition , the role of trans-dominant inhibition of poly ( ADP-ribosyl ) ation , which strongly reduces DSB rejoining , was assessed in comparison with 3 - aminobenzamide . METHODS AND MATERIALS : COM 3 rodent cells carry a construct for the dexamethasone-inducible overexpression of the DNA-binding domain of P09874 REA and exhibit greatly impaired DSB rejoining after irradiation . Telomerase activity was measured using polymerase chain reaction ELISA 1 h after irradiation with doses up to 10 Gy . Phosphorylation status of P31749 REA / Akt and of PKCalpha / beta ( II ) was assessed by western blotting . RESULTS : No telomerase upregulation was detectable for irradiated cells with undisturbed DSB rejoining . In contrast , incubation with LY294002 or dexamethasone yielded pronounced radiation induction of telomerase activity that could be suppressed by Wortmannin . 3 - Aminobenzamide not only was unable to induce telomerase activity but also suppressed telomerase upregulation upon incubation with LY294002 or dexamethasone . Phospho - P31749 REA was detectable independent of irradiation or dexamethasone pretreatment , but was undetectable upon incubations with LY294002 or Wortmannin , whereas phospho-PKC rested detectable . CONCLUSIONS : Telomerase activation postirradiation was triggered by different treatments that interfere with DNA DSB processing . This telomerase upregulation , however , was not reflected by the phosporylation status of the putative mediators of O14746 REA activation , P31749 REA and PKC . Although an involvement of P31749 REA in O14746 REA activation is not supported by the present findings , a respective role of PKC isoforms other than alpha / beta ( II ) can not be ruled out .

Activation of P34969 REA receptor stimulates neurite elongation through P42345 REA , Cdc 42 and actin filaments dynamics . Recent studies have indicated that the serotonin receptor subtype 7 ( 5 - HT7R ) plays a crucial role in shaping neuronal morphology during embryonic and early postnatal life . Here we show that pharmacological stimulation of 5 - HT7R using a highly selective agonist , LP - 211 , enhances neurite outgrowth in neuronal primary cultures from the cortex , hippocampus and striatal complex of embryonic mouse brain , through multiple signal transduction pathways . All these signaling systems , involving P42345 REA , the Rho GTPase Cdc 42 , Cdk 5 , and P29323 REA , are known to converge on the reorganization of cytoskeletal proteins that subserve neurite outgrowth . Indeed , our data indicate that neurite elongation stimulated by 5 - HT7R is modulated by drugs affecting actin polymerization . In addition , we show , by 2D Western blot analyses , that treatment of neuronal cultures with LP - 211 alters the expression profile of cofilin , an actin binding protein involved in microfilaments dynamics . Furthermore , by using microfluidic chambers that physically separate axons from the soma and dendrites , we demonstrate that agonist-dependent activation of 5 - HT7R stimulates axonal elongation . Our results identify for the first time several signal transduction pathways , activated by stimulation of 5 - HT7R , that converge to promote cytoskeleton reorganization and consequent modulation of axonal elongation . Therefore , the activation of 5 - HT7R might represent one of the key elements regulating CNS connectivity and plasticity during development .

Dependence on phosphoinositide 3 - kinase and DB01367 - RAF pathways drive the activity of RAF 265 , a novel RAF / P35968 REA inhibitor , and RAD 001 ( DB01590 MEN ) in combination . Activation of phosphatidylinositol - 3 - kinase ( PI3K ) - AKT and Kirsten rat sarcoma viral oncogene homologue ( P01116 REA ) can induce cellular immortalization , proliferation , and resistance to anticancer therapeutics such as epidermal growth factor receptor inhibitors or chemotherapy . This study assessed the consequences of inhibiting these two pathways in tumor cells with activation of P01116 REA , PI3K - AKT , or both . We investigated whether the combination of a novel RAF / vascular endothelial growth factor receptor inhibitor , RAF 265 , with a mammalian target of rapamycin ( P42345 REA ) inhibitor , RAD 001 ( everolimus ) , could lead to enhanced antitumoral effects in vitro and in vivo . To address this question , we used cell lines with different status regarding P01116 REA , P42336 REA , and P15056 REA mutations , using immunoblotting to evaluate the inhibitors , and MTT and clonogenic assays for effects on cell viability and proliferation . Subcutaneous xenografts were used to assess the activity of the combination in vivo . RAD 001 inhibited P42345 REA downstream signaling in all cell lines , whereas RAF 265 inhibited RAF downstream signaling only in P15056 REA mutant cells . In vitro , addition of RAF 265 to RAD 001 led to decreased AKT , S6 , and P06730 REA binding protein 1 phosphorylation in HCT 116 cells . In vitro and in vivo , RAD 001 addition enhanced the antitumoral effect of RAF 265 in HCT 116 and H460 cells ( both P01116 REA mut , P42336 REA mut ) ; in contrast , the combination of RAF 265 and RAD 001 yielded no additional activity in A549 and MDAMB 231 cells . The combination of RAF and P42345 REA inhibitors is effective for enhancing antitumoral effects in cells with deregulation of both DB01367 - RAF and PI3K , possibly through the cross-inhibition of 4E binding protein 1 and S6 protein .

Acute P34969 REA receptor activation increases DB01221 - evoked currents and differentially alters DB01221 receptor subunit phosphorylation and trafficking in hippocampal neurons . BACKGROUND : N-methyl-D-aspartate ( DB01221 ) receptors are regulated by several G protein-coupled receptors ( GPCRs ) as well as receptor tyrosine kinases . Serotonin ( 5 - HT ) type 7 receptors are expressed throughout the brain including the thalamus and hippocampus . Long-term ( 2-24 h ) activation of P34969 REA receptors promotes the expression of neuroprotective growth factor receptors , including the platelet-derived growth factor ( PDGF ) β receptors which can protect neurons against DB01221 - induced neurotoxicity . RESULTS : In contrast to long-term activation of P34969 REA receptors , acute ( 5 min ) treatment of isolated hippocampal neurons with the P34969 REA receptor agonist 5 - carboxamidotryptamine ( 5 - CT ) enhances DB01221 - evoked peak currents and this increase in peak currents is blocked by the P34969 REA receptor antagonist , SB 269970 . In hippocampal slices , acute P34969 REA receptor activation increases Q9UHB4 DB01221 receptor subunit phosphorylation and differentially alters the phosphorylation state of the Q13224 REA and Q12879 REA subunits . DB01221 receptor subunit cell surface expression is also differentially altered by P34969 REA receptor agonists : Q13224 REA cell surface expression is decreased whereas Q9UHB4 and Q12879 REA surface expression are not significantly altered . CONCLUSIONS : In contrast to the negative regulatory effects of long-term activation of P34969 REA receptors on DB01221 receptor signaling , acute activation of P34969 REA receptors promotes DB01221 receptor activity . These findings highlight the potential for temporally differential regulation of DB01221 receptors by the P34969 REA receptor .

Stimulation of cyclic AMP formation in the circular smooth muscle of human colon by activation of Q13639 REA - like receptors . 5 - HT stimulated cyclic AMP generation in human colonic circular smooth muscle in a concentration-dependent fashion ( EC50 = 229.1 nM ) . DAU 6236 also increased cyclic AMP formation and was a partial agonist relative to 5 - HT . GR 113808 inhibited the cyclic AMP formation induced by 5 - HT with a - log Ki value of 9.1 and an apparent pA2 value of 9.2 . DB00904 MEN and methysergide failed to inhibit cyclic AMP formation induced by 5 - HT . These results indicate that the Q13639 REA receptors of human colonic circular muscle mediate relaxation and inhibition of spontaneous contractions via formation of cyclic AMP .

[ DB00391 MEN in the management of functional dyspepsia and delayed gastric emptying ] . DB00391 MEN is a sulpiride isomer that exerts its prokinetic action through a dual mechanism : 1 ) as a P14416 REA antagonist and 2 ) as a serotonin 5HT ( 4 ) receptor agonist , conferring this drug with a cholinergic effect . At a dosage of 25mg three times daily , levosulpiride accelerates gastric and gallbladder emptying . Clinical trials have shown that this agent is more effective than placebo in reducing the symptoms of dyspepsia , while comparative studies have demonstrated that its effect is similar or superior to that of other dopamine antagonists . The safety profile of levosulpiride is good and the frequency of adverse events is similar to that of other D ( 2 ) dopamine antagonists . Therefore , this drug is a useful therapeutic option in the management of patients with functional dyspepsia , as well as in those with delayed gastric emptying .

DB00502 MEN induces neurotoxicity by the DB01221 receptor downstream signaling pathway , alternative from glutamate excitotoxicity . The DB01221 receptor is believed to be important in a wide range of nervous system functions including neuronal migration , synapse formation , learning and memory . In addition , it is involved in excitotoxic neuronal cell death that occurs in a variety of acute and chronic neurological disorders . Besides of agonist / coagonist sites , other modulator sites , including butyrophenone site may regulate the N-methyl-D-aspartate receptor . It has been shown that haloperidol , an antipsychotic neuroleptic drug , interacts with the Q13224 REA subunit of DB01221 receptor and inhibits DB01221 response in neuronal cells . We found that DB01221 receptor was co-immunoprecipitated by anti-Ras antibody and this complex , beside NR2 subunit of DB01221 receptor contained haloperidol-binding proteins , P29475 REA and Ras - P01286 REA . Furthermore , we have shown that haloperidol induces neurotoxicity of neuronal cells via DB01221 receptor complex , accompanied by dissociation of Ras - P01286 REA from membranes and activation of c-Jun-kinase . Inclusion of insulin prevented relocalization of Ras - P01286 REA and subsequent neuronal death . DB00502 MENMAX DB00502 MEN - induced dissociation of Ras - P01286 REA leads to inhibition of membrane-bound form of Ras protein and changes downstream regulators activity that results in the initiation of the apoptotic processes via the mitochondrial way . Our results suggest that haloperidol induces neuronal cell death by the interaction with DB01221 receptor , but through the alternative from glutamate excitotoxicity signaling pathway .

Poly ( DB02059 ) polymerase - 1 signalling of the DNA damage induced by P11387 REA poison in D54 ( p53wt ) and U251 ( p53mut ) glioblastoma cell lines . Glioblastomas are widely characterised by the mutation of the p53 gene and p53 disruption sensitizes glioblastoma cells to P11387 REA ( TOPO I ) inhibitor-mediated apoptosis . We investigated the effects of combined treatments with the P11387 REA inhibitor DB01030 MEN and the poly ( DB02059 ) polymerase - 1 inhibitor DB02690 in D54 ( p53wt ) and U251 ( p53mut ) glioblastoma cell lines . Analysis of cell growth and cell cycle kinetics showed a synergistic anti-proliferative effect of 10 nM TPT and 10 microM DB02690 and a G2 / M block of the cell cycle . We also evaluated , the influence of TPT + / - DB02690 treatment on P09874 REA and p53 activity . We got evidences of a TPT-dependent increase of P09874 REA auto-modification level in both the cells . Moreover , in the D54 ( p53wt ) cells we found that in co-treatments DB02690 incremented the TPT-dependent stimulation of p53 transcriptional activity and increased the P38936 REA nuclear amount . Conversely , in U251 ( p53mut ) cells we found that DB02690 incremented the TPT-dependent apoptosis characterised by P09874 REA proteolysis . Our findings suggest that the modulation of P09874 REA can be considered a strategy in the potentiation of the chemotherapeutic action of TOPO I poisons in glioblastoma cells apart from their p53 status .