interacts_with DB00281?
Serotonergic mechanisms in human allergic contact dermatitis . Expression of serotonin ( 5-hydroxytryptamine ; 5-HT ) , 5-HT receptors 1A ( 5-HT1AR ) and 2A , and serotonin transporter protein ( P31645 ) was studied in positive epicutaneous reactions to nickel sulphate in nickel-allergic patients , at 72 h post-challenge with the antigen . In addition , the effects of 5-HT2AR agonist 2,5-dimethoxy-4-iodoamphetamine ( DOI ) , and the selective serotonin reuptake inhibitors ( SSRIs ) citalopram and fluoxetine , were tested on nickel-stimulated peripheral blood mononuclear cells from nickel-allergic patients , regarding their proliferation and interleukin ( IL ) -2 production , as well as the effect of these SSRIs on a murine Langerhans ' cell-like line ( XS52 ) , regarding its IL-1beta production . Serotonin-positive platelets were increased in the inflamed skin compared with control skin . A decrease ( p < 0.01 ) in 5-HT1AR-positive mononuclear cells was evident in the eczematous skin compared with control skin , whereas 5-HT2AR- and P31645 -positive cells were increased ( p < 0.001 for both ) in the eczematous skin . Treatment of nickel-stimulated peripheral blood mononuclear cells with 5x10(-5) mol/l of DOI inhibited ( p < 0.01 ) the proliferation of nickel-stimulated peripheral blood mononuclear cells , while no effect was found regarding P60568 production . DB00215 at 10(-6) mol/l tended to inhibit the production of IL-1beta by the XS52 cell line . These results indicate the implication of the serotonergic system in the contact allergic reaction . Expression of P20839 and P12268 after transplantation and initiation of immunosuppression . BACKGROUND : DB01024 ( DB00603 ) mediates immunosuppressive effects by inhibiting inosine monophosphate dehydrogenase ( IMPDH ) . Induction of IMPDH activity has been observed in whole blood and erythrocyte samples during immunosuppressive therapy . Information concerning the mechanisms for increased IMPDH activity is limited and the potential implications of induction have been debated . METHODS : Whole blood , P01730 + cell , and reticulocyte samples were collected from 30 renal transplant patients pre- and posttransplantation . The expressions of two IMPDH isoforms , type 1 and 2 , were analyzed by real-time reverse-transcription polymerase chain reaction and quantified using a housekeeping gene index . The IMPDH activity was determined by ultraviolet high-performance liquid chromatography . RESULTS : Transplantation and the initiation of immunosuppressive therapy was associated with increased P20839 ( 50-88 % , P < 0.0005 ) and decreased P12268 ( 42-56 % , P < 0.0005 ) expression . In P01730 + cells , however , P12268 increased ( 15 % , P=0.009 ) . These changes are probably related to glucocorticoid effects . Two weeks posttransplant , DB00603 -treated patients displayed elevated P20839 and 2 in reticulocytes , suggesting enzyme induction in these cells during prolonged DB00603 therapy . Patients with acute rejection during follow-up demonstrated higher P12268 expression in P01730 + cells pretransplant than nonrejecting patients ( median expression 1.26 vs. 0.87 respectively , P=0.017 ) . CONCLUSIONS : Knowledge of changes in P20839 and 2 expression after transplantation and initiation of immunosuppression is important considering the action of DB00603 on IMPDH and the potential for pharmacodynamic monitoring of DB00603 by measuring IMPDH activity . The expression of P12268 in P01730 + cells pretransplant may be an indicator of immune activation . Differential radiosensitisation by ZD1839 ( DB00317 ) , a highly selective epidermal growth factor receptor tyrosine kinase inhibitor in two related bladder cancer cell lines . The epidermal growth factor receptor ( P00533 ) is expressed in a wide variety of epithelial tumours including carcinoma of the bladder . Stimulation of the P00533 pathway is blocked by ZD1839 ( DB00317 ) , a highly selective P00533 tyrosine kinase inhibitor . Radical radiotherapy is an established organ sparing treatment option for muscle invasive bladder cancer and this study has explored the possibility for the use of ZD1839 as a radiosensitiser in this scenario . The effect of combination treatment with ZD1839 ( 0.01 microM ) and ionising radiation in the established bladder cancer cell lines MGH-U1 and its radiosensitive mutant clone S40b was measured by clonogenic assays . A highly significant radiosensitising effect was seen in both cell lines ( P < 0.001 for MGH-U1 and S40b cell lines ) . This effect was independent of the concentration of the drug and the duration of exposure prior to treatment with ionising radiation . Cell cycle kinetics of both cell lines was not significantly altered with ZD1839 ( 0.01 microM ) as a single agent . A modest induction of apoptosis was observed with ZD1839 ( 0.01 microM ) as a single agent , but a marked induction was observed with the combination treatment of ZD1839 and ionising radiation . These results suggest a potentially important role for ZD1839 in combination with radiotherapy in the treatment of muscle invasive bladder cancer . Class I histone deacetylase activity is required for proliferation of renal epithelial cells . The process of renal regeneration after acute kidney injury is thought to recapitulate renal development , and proliferation of renal proximal tubular cells ( RPTCs ) is a critical step in the regenerative response . Recent studies indicate that class I histone deacetylases ( HDACs ) are required for embryonic kidney gene expression , growth , and differentiation . The role and underlying mechanisms of class I HDAC activation in RPTC proliferation , however , remain unclear . In this study , we used cultured RPTCs to examine this issue since four class I HDAC isoforms ( 1 , 2 , 3 , and 8 ) are abundantly expressed in this cell type . Blocking class I HDAC activity with a highly selective inhibitor , MS-275 , induced global histone H3 hyperacetylation , reduced RPTC proliferation , and diminished expression of cyclin D1 and proliferating cell nuclear antigen . Silencing Q13547 , 3 , or 8 with small interfering RNA resulted in similar biological effects . Activation of epidermal growth factor receptor ( P00533 ) and signal transducers and activators of transcription 3 ( P40763 ) was required for RPTC proliferation , and P40763 functioned downstream of P00533 . Treatment with MS-275 or knockdown of Q13547 , 3 , or 8 suppressed P00533 expression and phosphorylation , and silencing Q13547 and 3 also reduced P40763 phosphorylation . However , Q92769 downregulation did not affect RPTC proliferation and phosphorylation of P00533 and P40763 . Collectively , these data reveal a critical role of class I HDACs in mediating proliferation of renal epithelial cells through activation of the P00533 / P40763 signaling pathway . The antiproliferative effect of lidocaine on human tongue cancer cells with inhibition of the activity of epidermal growth factor receptor . Local anesthetics suppress proliferation in several cancer cells . The mechanism of the suppression , however , is unknown . Our previous study shows that lidocaine , at the level of tissue concentration under topical or local administration , has a direct inhibitory effect on the activity of epidermal growth factor receptor ( P00533 ) , which is a potential target for antiproliferation in cancer cells . Therefore , we hypothesized that lidocaine would suppress the proliferation of cancer cells through the inhibition of P00533 activity . We investigated the effects of lidocaine ( 40-4000 microM ) on proliferation of a human tongue cancer cell line , CAL27 , which has a high level of P00533 expression , and also examined the effect of lidocaine on epidermal growth factor ( P01133 ) -stimulated autophosphorylation of P00533 in CAL27 cells . A clinical concentration of lidocaine ( 400 microM ) suppressed both serum-induced and P01133 -induced proliferation of CAL27 cells and inhibited P01133 -stimulated tyrosine kinase activity of P00533 without cytotoxicity . A larger concentration of lidocaine ( 4000 microM ) showed cytotoxicity with an antiproliferative effect . We suggest that the inhibition of P01133 -stimulated P00533 activity is one of the mechanisms of the antiproliferative effect of lidocaine on CAL27 cells . DB00281 administered topically within the oral cavity for cancer pain relief may suppress the proliferation of human tongue cancer cells . Dermatological adverse events from P15056 inhibitors : a growing problem . The development of targeted therapies has ushered in a new era in the management of melanoma . Inhibitors of the DB01367 -RAF-MEK- P29323 pathway have taken the center stage with development at a rapid pace . DB08881 was recently approved by regulatory agencies , and other agents ( e.g. dabrafenib ) are in various stages of clinical testing . These agents are producing remarkable results for patients , but are also presenting new challenges . Clinical toxicities and drug resistance are topmost issues . Some of the most common and vivid representations of adverse events to these agents are the dermatologic manifestations . Published trials and initial observations reflect a toxicity profile ( e.g. squamous cell carcinomas/keratoacanthomas , maculopapular rashes , hyperkeratosis ) that is distinct from cutaneous toxicities from P00533 and P42345 inhibitors ( acneiform rash , paronychia , xerosis ) . Their management extends beyond conservative treatment and includes specific physical and surgical treatment modalities , skill sets unique to dermatologists . All these pose significant challenges to clinicians , and sound knowledge of such toxicities and their management will likely result in improved patient outcomes and quality of life . In this manuscript , we provide an overview of the emerging scientific literature on dermatological adverse events arising out of P15056 inhibition . Targeting Q01196 / Q06455 -histone deacetylase repressor complex : a novel mechanism for valproic acid-mediated gene expression and cellular differentiation in Q01196 / Q06455 -positive acute myeloid leukemia cells . In t(8;21) acute myeloid leukemia ( AML ) , the Q01196 / Q06455 fusion protein promotes leukemogenesis by recruiting class I histone deacetylase ( HDAC ) -containing repressor complex to the promoter of Q01196 target genes . Valproic acid ( DB00313 ) , 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 causes selective proteasomal degradation of Q92769 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 / Q06455 fusion protein that also recruits Q13547 , a key regulator of normal and aberrant histone acetylation . We report here that DB00313 treatment disrupts the Q01196 / Q06455 - Q13547 physical interaction , stimulates the global dissociation of Q01196 / Q06455 - Q13547 complex from the promoter of Q01196 / Q06455 target genes , and induces relocation of both Q01196 / Q06455 and Q13547 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 ) otherwise silenced by Q01196 / 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 might effectively target Q01196 / Q06455 -driven leukemogenesis through disruption of aberrant Q13547 function and that DB00313 should be integrated in novel therapeutic approaches for Q01196 / Q06455 -positive AML . Characteristics of early murine B-lymphocyte precursors and their direct sensitivity to negative regulators . Recently , a collection of surface markers was exploited to isolate viable Lin(-) TdT(+) cells from murine bone marrow . These early pro-B cells were enriched for B-lineage lymphocyte precursor activity measured by short-term culture and had little responsiveness to myeloid growth factors . Early precursors can be propagated with remarkably high cloning frequencies in stromal cell-free , serum-free cultures , permitting this analysis of direct regulatory factors . Expression of the interleukin-7 receptor ( IL-7Ralpha ) chain marks functional precursors and P13232 is necessary for progression beyond the CD45RA(+) P15391 (-) stage . Efficient survival and differentiation were only observed when stem cell factor and Flt-3 ligand were also present . P13232 -responsive P15391 (+) precursors are estrogen resistant . However , B-lineage differentiation was selectively abrogated when highly purified Lin(-) precursors were treated with hormone in the absence of stromal cells . In addition , early stages of B lymphopoiesis were arrested by limitin , a new interferon ( IFN ) -like cytokine as well as IFN-alpha , P01579 , or transforming growth factor beta ( TGF-beta ) , but not by epidermal growth factor ( P01133 ) . Lin(-) TdT(+) early pro-B cells are shown here to be P26842 (+) AA4.1(+/-)Ki-67(+) Ly-6C(-) Ly-6A/Sca-1(Lo/-)Thy-1(-) P16150 (+) P01730 (+/-)CD16/32(Lo/-) P16070 (Hi) and similar in some respects to the " common lymphoid progenitors " ( CLP ) identified by others . Although early pro-B cells have lost myeloid differentiation potential , transplantation experiments described here reveal that at least some can generate T lymphocytes . Of particular importance is the demonstration that a pivotal early stage of lymphopoiesis is directly sensitive to negative regulation by hormones and cytokines . Potentiator ivacaftor abrogates pharmacological correction of ΔF508 P13569 in cystic fibrosis . Cystic fibrosis ( CF ) is caused by mutations in the CF transmembrane conductance regulator ( P13569 ) . Newly developed " correctors " such as DB09280 ( VX-809 ) that improve P13569 maturation and trafficking and " potentiators " such as ivacaftor ( VX-770 ) that enhance channel activity may provide important advances in CF therapy . Although VX-770 has demonstrated substantial clinical efficacy in the small subset of patients with a mutation ( G551D ) that affects only channel activity , a single compound is not sufficient to treat patients with the more common P13569 mutation , ΔF508 . Thus , patients with ΔF508 will likely require treatment with both correctors and potentiators to achieve clinical benefit . However , whereas the effectiveness of acute treatment with this drug combination has been demonstrated in vitro , the impact of chronic therapy has not been established . In studies of human primary airway epithelial cells , we found that both acute and chronic treatment with VX-770 improved P13569 function in cells with the G551D mutation , consistent with clinical studies . In contrast , chronic VX-770 administration caused a dose-dependent reversal of VX-809-mediated P13569 correction in ΔF508 homozygous cultures . This result reflected the destabilization of corrected ΔF508 P13569 by VX-770 , markedly increasing its turnover rate . Chronic VX-770 treatment also reduced mature wild-type P13569 levels and function . These findings demonstrate that chronic treatment with P13569 potentiators and correctors may have unexpected effects that can not be predicted from short-term studies . Combining these drugs to maximize rescue of ΔF508 P13569 may require changes in dosing and/or development of new potentiator compounds that do not interfere with P13569 stability . Effects of P28335 -receptor expression on cell proliferation control in hamster fibroblasts : serotonin fails to induce a transformed phenotype . 5-HT1c receptors have been shown to act as protooncogenes in NIH 3T3 cells , inducing ligand-dependent focus formation . In order to assess their mitogenic and oncogenic potential in a different cell system , we transfected these receptors into CCL39 hamster fibroblasts , a well-characterized growth factor-dependent cell line . Cell clones expressing functional receptors were isolated and tested for ( a ) growth factor dependence of proliferation measuring thymidine incorporation in response to varying doses of serum , ( b ) the response to serotonin alone or in combination with other growth factors , and ( c ) the capacity for anchorage-independent proliferation . In the absence or presence of serotonin , the large majority of the clones isolated showed normal morphology and normal growth factor dependence and was unable to grow in soft agar . None of the clones showed a significant response to serotonin alone in DNA synthesis reinitiation experiments , but synergy was observed between serotonin and the tyrosine kinase activating growth factors P01133 and FGF . However , the major part of this effect could be abolished by an antagonist of 5-HT1b receptors , which are endogenous in CCL39 cells . The same receptor was found to mediate a significant mitogenic response to the neurotransmitter in Ha-ras-transfected cells . The fact that 5-HT1c receptors do not readily induce a transformed phenotype in CCL39 cells clearly distinguishes them from strong dominantly acting oncogene products like DB01367 , P12931 , or P07333 . OSU-03012 and Viagra Treatment Inhibits the Activity of Multiple Chaperone Proteins and Disrupts the Blood-Brain Barrier : Implications for Anti-Cancer Therapies . We examined the interaction between OSU-03012 ( also called AR-12 ) with phosphodiesterase 5 ( O76074 ) inhibitors to determine the role of the chaperone glucose-regulated protein ( P11021 ) / P11021 / P11021 in the cellular response . DB00203 ( Viagra ) interacted in a greater than additive fashion with OSU-03012 to kill stem-like GBM cells . Treatment of cells with OSU-03012/sildenafil : abolished the expression of multiple oncogenic growth factor receptors and plasma membrane drug efflux pumps and caused a rapid degradation of P11021 and other HSP70 and HSP90 family chaperone proteins . Decreased expression of plasma membrane receptors and drug efflux pumps was dependent upon enhanced Q9NZJ5 -eIF2α- P18848 - P35638 signaling and was blocked by P11021 over-expression . In vivo OSU-03012/sildenafil was more efficacious than treatment with celecoxib and sildenafil at killing tumor cells without damaging normal tissues and in parallel reduced expression of P08183 and Q9UNQ0 in the normal brain . The combination of OSU-03012/sildenafil synergized with low concentrations of sorafenib to kill tumor cells , and with lapatinib to kill P00533 over-expressing tumor cells . In multiplex assays on plasma and human tumor tissue from an OSU-03012/sildenafil treated mouse , we noted a profound reduction in uPA signaling and identified FGF and P23458 /2 as response biomarkers for potentially suppressing the killing response . Inhibition of FGFR signaling and to a lesser extent P23458 /2 signaling profoundly enhanced OSU-03012/sildenafil lethality . Endogenous concentrations of ouabain act as a cofactor to stimulate fluid secretion and cyst growth of in vitro ADPKD models via DB02527 and P00533 -Src-MEK pathways . In autosomal-dominant polycystic kidney disease ( ADPKD ) , renal cysts develop by aberrant epithelial cell proliferation and transepithelial fluid secretion . We previously showed that ouabain increases proliferation of cultured human ADPKD cells via stimulation of the P01133 receptor ( P00533 ) -Src-MEK/ P29323 signaling pathway . We examined whether ouabain affects fluid secretion and in vitro cyst growth of human ADPKD cell monolayers , ADPKD cell microcysts cultured in a three-dimensional collagen matrix , and metanephric organ cultures from Pkd1(m1Bei) mice . Physiological concentrations of ouabain alone did not affect net transepithelial basal-to-apical fluid transport in ADPKD monolayers or growth of cultured ADPKD microcysts . In contrast , in the presence of forskolin or 8-bromo- DB02527 , ouabain significantly enhanced ADPKD fluid secretion and microcyst expansion . Ouabain exerted this effect by enhancing DB02527 -dependent Cl(-) secretion via the P13569 . Similarly , ouabain accelerated DB02527 -dependent cyst enlargement in Pkd1(m1Bei) mice metanephroi , with a more prominent response in homozygous than heterozygous mice . Ouabain had no effect on fluid secretion and cystogenesis of normal human kidney cells and caused only slight cystic dilations in wild-type mouse kidneys . The effects of ouabain in ADPKD cells and Pkd1(m1Bei) metanephroi were prevented by inhibitors of P00533 ( AG1478 ) , Src ( Q99463 ) , and MEK ( U0126 ) . Together , our results show that ouabain , used in physiological concentrations , has synergistic effects on DB02527 -mediated fluid secretion and cyst growth , via activation of the P00533 -Src-MEK pathway . These data provide important evidence for the role of ouabain as an endogenous hormone that exacerbates ADPKD cyst progression . Targeted treatment of advanced and metastaticbreast cancer with lapatinib . Improved molecular understanding of breast cancer in recent years has led to the discovery of important drug targets such as HER-2 and P00533 . DB01259 is a potent dual inhibitor of HER-2 and P00533 . Preclinical and phase I studies have shown activity with lapatinib in a number of cancers , including breast cancer , and the drug is well tolerated . The main known drug interactions are with paclitaxel and irinotecan . The most significant side-effects of lapatinib are diarrhea and adverse skin events . Rates of cardiotoxicity compare favorably with trastuzumab , a monoclonal antibody against HER-2 . This paper focuses on lapatinib in advanced and metastatic breast cancer , which remains an important therapeutic challenge . Phase II and III studies show activity as monotherapy , and in combination with chemotherapy or hormonal agents . Results from these studies suggest that the main benefit from lapatinib is in the HER-2 positive breast cancer population . Combinations of lapatinib and trastuzumab are also being studied and show encouraging results , particularly in trastuzumab-refractory metastatic breast cancer . DB01259 may have a specific role in treating HER-2 positive CNS metastases . The role of lapatinib as neoadjuvant therapy and in early breast cancer is also being evaluated . Local immunotherapy of glioma patients with a combination of 2 bispecific antibody fragments and resting autologous lymphocytes : evidence for in situ t-cell activation and therapeutic efficacy . After adoptive transfer of pre-activated lymphocytes into the operation cavity of glioma patients , tumor regression and improved survival have been reported in some patients . Results were most impressive when bispecific antibodies with tumor x CD3 specificity were also applied . In this study , we attempted to avoid time-consuming pre-activation procedures for adoptively transferred cells by using a combination of bispecific antibodies directed to the P01133 receptor ( P00533 ) on tumor cells and to CD3 and P10747 on T cells . Eleven patients with high-grade malignant glioma received 3 injections of 2 bispecific antibody fragments ( P00533 x CD3 and P00533 x P10747 ) together with freshly isolated autologous lymphocytes via an Ommaya reservoir . Intracavitary fluid aspirated during immunotherapy was examined for markers of T-cell activation . Increased levels of soluble P60568 receptor and P01375 were detected in the intracavitary fluid of all patients tested . Two of the 11 treated patients experienced a beneficial response to therapy as defined by a transient contrast enhancement in subsequent Q9BWK5 scans and prolonged survival . Side effects were transient and consisted of fever , nausea , headache and aggravation of pre-existing neurologic deficits . These adverse effects were most likely due to the antibody construct containing anti-CD3 specificity . Two patients developed cerebral edema and required steroid treatment . The P28335 receptor agonist lorcaserin reduces nicotine self-administration , discrimination , and reinstatement : relationship to feeding behavior and impulse control . DB04871 ( ( 1R ) -8-chloro-1-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine HCl ) is a selective 5-HT(2C) receptor agonist with clinical efficacy in phase-III obesity trials . Based on evidence that this drug class also affects behaviors motivated by drug reinforcement , we compared the effect of lorcaserin on behavior maintained by food and nicotine reinforcement , as well as the stimulant and discriminative stimulus properties of nicotine in the rat . Acutely administered lorcaserin ( 0.3-3 mg/kg , subcutaneous ( SC ) ) dose dependently reduced feeding induced by 22-h food deprivation or palatability . Effects up to 1 mg/kg were consistent with a specific effect on feeding motivation . DB04871 ( 0.6-1 mg/kg , SC ) reduced operant responding for food on progressive and fixed ratio schedules of reinforcement . In this dose range lorcaserin also reversed the motor stimulant effect of nicotine , reduced intravenous self-administration of nicotine , and attenuated the nicotine cue in rats trained to discriminate nicotine from saline . DB04871 also reduced the reinstatement of nicotine-seeking behavior elicited by a compound cue comprising a nicotine prime and conditioned stimulus previously paired with nicotine reinforcement . DB04871 did not reinstate nicotine-seeking behavior or substitute for a nicotine cue . Finally , lorcaserin ( 0.3-1 mg/kg ) reduced nicotine-induced increases in anticipatory responding , a measure of impulsive action , in rats performing the five-choice serial reaction time task . Importantly , these results indicate that lorcaserin , and likely other selective 5-HT(2C) receptor agonists , similarly affect both food- and nicotine-motivated behaviors , and nicotine-induced impulsivity . Collectively , these findings highlight a therapeutic potential for 5-HT(2C) agonists such as lorcaserin beyond obesity into addictive behaviors , such as nicotine dependence . DB00281 inhibits tyrosine kinase activity of the epidermal growth factor receptor and suppresses proliferation of corneal epithelial cells . BACKGROUND : Although lidocaine is recognized as an excellent topical corneal analgesic , its toxic effect on corneal epithelial cells limits its use during corneal epithelial wound healing . Mechanism of the impairment of corneal reepithelialization with lidocaine , however , has not been evaluated . The authors ' previous study revealed that lidocaine inhibits the activity of tyrosine kinase receptors through the interaction with specific amino acid sequences around autophosphorylation sites , including acidic , basic , and aromatic amino acids . P00533 ( P00533 ) , a tyrosine kinase receptor with an important role in epithelial cell proliferation after corneal wounding , also possesses these amino acids sequences around autophosphorylation sites . The authors hypothesized that lidocaine would suppress tyrosine kinase activity of P00533 and would impair corneal epithelial cell proliferation . METHODS : To investigate the effect of lidocaine ( 4 microM-40 mM ) on epidermal growth factor ( P01133 ) -stimulated autophosphorylation of P00533 , the authors studied purified P00533 in microtubes . They cultured human corneal epithelial cells ( HCECs ) with P01133 and lidocaine to investigate the effect of lidocaine on cell proliferation and on autophosphorylation of P00533 in HCECs . RESULTS : DB00281 ( > or =400 microM ) significantly suppressed P01133 -stimulated autophosphorylation of the purified P00533 . In the HCEC study , P01133 alone stimulated cell proliferation and increased autophosphorylation of P00533 in HCECs . DB00281 ( > or = 400 microM ) significantly suppressed both the proliferation of HCECs promoted by P01133 and P01133 -stimulated autophosphorylation of P00533 . CONCLUSION : DB00281 directly inhibits tyrosine kinase activity of P00533 and suppresses the corneal epithelial cell proliferation .