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Prepublished online as a Blood First Edition Paper on January 16, 2003; DOI 10.1182/blood-2002-07-2307.
NEOPLASIA
From Preclinical Research and Exploratory
Development, SUGEN, South San Francisco, CA; and the Department of
Medicine and Oregon Health and Science University (OHSU) Cancer
Institute, Division of Hematology and Medical Oncology, OHSU and
Portland Veterans Affairs Medical Center, OR.
FLT3 (fms-related tyrosine kinase/Flk2/Stk-2) is a receptor
tyrosine kinase (RTK) primarily expressed on hematopoietic cells. In blasts from acute myelogenous leukemia (AML) patients, 2 classes of FLT3 activating mutations have been identified: internal
tandem duplication (ITD) mutations in the juxtamembrane domain
(25%-30% of patients) and point mutations in the kinase domain
activation loop (7%-8% of patients). FLT3-ITD mutations are the most
common molecular defect identified in AML and have been shown to be an independent prognostic factor for decreased survival. FLT3-ITD is
therefore an attractive molecular target for therapy. SU11248 is a
recently described selective inhibitor with selectivity for split
kinase domain RTKs, including platelet-derived growth factor receptors, vascular endothelial growth factor receptors, and
KIT. We show that SU11248 also has potent activity against wild-type FLT3 (FLT3-WT), FLT3-ITD, and FLT3 activation loop
(FLT3-Asp835) mutants in phosphorylation assays. SU11248
inhibits FLT3-driven phosphorylation and induces apoptosis in
vitro. In addition, SU11248 inhibits FLT3-induced VEGF production.
The in vivo efficacy of SU11248 was investigated in 2 FLT3-ITD
models: a subcutaneous tumor xenograft model and a bone marrow
engraftment model. We show that SU11248 (20 mg/kg/d) dramatically
regresses FLT3-ITD tumors in the subcutaneous tumor xenograft model and
prolongs survival in the bone marrow engraftment model. Pharmacokinetic and pharmacodynamic analysis in subcutaneous tumors showed that a
single administration of an efficacious drug dose potently inhibits FLT3-ITD phosphorylation for up to 16 hours following a single dose.
These results suggest that further exploration of SU11248 activity in AML patients is warranted.
(Blood. 2003;101:3597-3605) Signaling via receptor tyrosine kinases
(RTKs) is frequently dysregulated in disease. FLT3 (fms-related
tyrosine kinase/Flk2/Stk-2) belongs to the type III split-kinase domain
family of RTKs, and is primarily expressed on immature hematopoietic
progenitors and also on some mature myeloid and lymphoid
cells.1-3 FLT3 is activated following binding of FLT3
ligand (FL), which causes receptor dimerization leading to increased
kinase activity and activation of downstream signaling pathways
including Stat5, Ras, and PI3'kinase.4-6 FLT3 normally
regulates survival and proliferation of hematopoietic progenitor cells,
in particular by synergy with other RTKs and cytokine
receptors.7-9 FLT3 is also expressed on acute myelogenous leukemia (AML) cells from the majority of patients and stimulates survival and proliferation of leukemic blasts.10-12
Two classes of activating FLT3 mutations have been identified in AML
patients: internal tandem duplication (ITD) mutations in the
juxtamembrane region expressed in 25% to 30% of AML patients, and
point mutations in the activation loop of the kinase domain found in
approximately 7% of patients (for review, see Gilliland and
Griffin13). Both classes of mutation result in
constitutive FLT3 tyrosine kinase activity and have been shown to
transform hematopoietic cell lines in vitro and in
vivo.5,14 Recently Kelly et al15 have
reported that hematopoietic reconstitution with primary bone marrow
cells transduced with FLT3-ITD causes myeloproliferative disease in
mice, with a latency period of 40 to 60 days. FLT3-ITD has also been
shown to cooperate with promyelocytic leukemia-retinoic-acid receptor
FLT3-ITD is the most frequently observed molecular defect in AML
and has been found in pediatric, adult, and elderly AML patients at
frequencies of 10% to 16%, 21% to 27%, and 24% to 34%,
respectively.17-20 FLT3-ITD has been shown to be the
single most significant poor prognosis factor in AML in several recent
independent studies.21-23 Clinically, FLT3-ITD is
associated with increased leukocytosis, increased blast count,
increased relapse rate, decreased disease-free survival, and poor
overall survival. A recent study has shown that an increased ratio of
FLT3-ITD relative to wild-type FLT3 (FLT3-WT) confers a poorer
prognosis and that the FLT3-WT allele is absent in a minority of
patients.24 The catalytic Asp835 point mutation is also
associated with leukocytosis and poor prognosis, though not as
statistically significant as FLT3-ITD.25 FLT3 therefore
appears to be necessary for disease progression and is an attractive
target for consideration in AML therapies.
Other split kinase RTKs such as vascular endothelial growth factor
receptor 2 (VEGFR2; KDR) may play a role in the pathophysiology of AML by regulation of bone marrow angiogenesis. Increased bone marrow
vascularity and increased cellular VEGF levels are evident in AML
patients and predict a poor outcome.26-28 Paracrine
interactions between the bone marrow microenvironment and AML blasts
likely play a role in increasing microvessel density and contributing to blast cell survival and proliferation (for review see Fiedler et
al29). Agents targeting VEGFR2 may therefore also have
clinical benefit in AML.
SU11248 is a small molecule that potently inhibits platelet-derived
growth factor receptors (PDGFR) Cell lines
Site-directed mutagenesis and transfection
Cell proliferation, apoptosis, and enzyme-linked immunosorbent assays (ELISAs) Cell lines were starved overnight in medium containing 0.1% FBS prior to addition of SU11248 and FL (50 ng/mL; FLT3-WT cells only). Proliferation was measured after 48 hours of culture using the Alamar Blue assay (Alamar Biosciences, Sacramento, CA) in triplicate for each condition, as described by the manufacturer. Trypan blue cell viability assays were performed in parallel and yielded similar results.VEGF ELISAs on culture supernatants were performed at 72 hours of culture in triplicate for each condition, as directed by the manufacturer (QuantiGlo human VEGF Immunoassay kit, R&D Systems). Apoptosis was measured 24 hours after compound addition by Western blotting to detect cleavage of poly (ADP-ribose) polymerase (PARP) or levels of caspase-3. Cells were lysed in lysis buffer (20 mM Tris [tris(hydroxymethyl)aminomethane], pH 7.5; 137 mM NaCl; 10% glycerol; 1% nonidet P-40 [NP-40]; 0.1% sodium dodecyl sulfate [SDS]; 2 mM EDTA [ethylenediaminetetraacetic acid]) containing protease and phosphatase inhibitors (50 mM sodium fluoride, 1 mM sodium orthovanadate, 2 mM Pefabloc, 1.2 µM aprotinin, 40 µM bestatin, 5.6 µM E-64, 4 µM leupeptin, and 4 µM pepstatin A). Equivalent amounts of protein were separated by SDS-polyacrylamide gel electrophoresis (PAGE), and then transferred to nitrocellulose membranes. Membranes were probed with an anti-PARP antibody (Cell Signaling Technology, Beverly, MA) or caspase-3 (Upstate Biotechnology, Lake Placid, NY). Immunoprecipitation and Western blot (IP/W) analysis For in vitro experiments, cells were treated with SU11248 for 2 hours in medium containing 0.1% FBS. Cells expressing FLT3-WT were stimulated with 150 ng/mL FL for 5 minutes. Cells were lysed as described above. Equivalent amounts of protein from each sample were immunoprecipitated overnight at 4°C with an agarose-conjugated anti-FLT3 antibody (Santa Cruz Biotechnology, Santa Cruz, CA). Immune complexes were washed (150 mM NaCl; 1.5 mM MgCl2; 50 mM HEPES [N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid], pH 7.5; 10% glycerol; 0.1% Triton X-100; and 1 mM EGTA [ethylene glycol tetraacetic acid]), and, following SDS-PAGE, proteins were transferred to nitrocellulose membranes. Membranes were probed with an antiphosphotyrosine antibody (Upstate Biotechnology, Lake Placid, NY, or Transduction Laboratories, Lexington, KY) and then stripped with Restore Western Blot Stripping Buffer (Pierce, Rockford, IL). Membranes were reprobed with an anti-FLT3 antibody (Santa Cruz Biotechnology). Stat5 antibodies for immunprecipitation and Western blot analysis were from Upstate Biotechnology and Transduction Laboratories, respectively.In vivo models Prior to implantation, cells were harvested during exponential growth, washed once with sterile phosphate-buffered saline (PBS), and, for subcutaneous injection, resuspended in Matrigel (BD Biosciences, Bedford, MA). All animal studies were carried out with the approval of the SUGEN Institutional Animal Care and Use Committee in an Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC) International accredited animal facility and were in accordance with the Institute of Laboratory Animal Research (National Institutes of Health, Bethesda, MD) Guide for the Care and Use of Laboratory Animals.32 Female athymic nu/nu mice (8 to 12 weeks old) were purchased from Charles River Laboratories (Wilmington, MA) and female nonobese diabetic-severe combined immunodeficiency (NOD-SCID) mice from Jackson Laboratories (Bar Harbor, ME). All animals were maintained under clean room conditions in sterile microisolator cages (Allentown Caging Equipment, Allentown, NJ) with Sani-Chips (PJ Murphy, Forest Products, Montville, NJ) and were provided sterile rodent chow and water ad libitum.Subcutaneous model. Athymic nu/nu mice received subcutaneous injections into the hind flank on day 0 with 5 × 106 MV4;11 or RS4;11 cells. In vivo experiments were scheduled to evaluate the therapeutic effects of daily oral administration of SU11248 on pre-existing tumors (size 300-500 mm3) in all studies. Animals were randomized into treatment groups of 10 mice each for efficacy studies and 2 to 3 mice each for target modulation studies. A range of doses of SU11248 or its vehicle were administered, as indicated in figure legends. SU11248 was delivered orally (PO) in a citrate-buffered solution (pH 3.5) by gavage. Tumor growth was measured twice weekly using Vernier calipers (Fowler, Des Plaines, IL) for the duration of the treatment. Tumor volumes were calculated as the product of length × width × height. Target modulation. Mice bearing tumors were administered a single oral dose of SU11248 at the indicated concentrations. Control animals received either no treatment (predose) or vehicle. At the indicated times after dosing, individual mice were killed, their tumors resected, and a blood sample taken by cardiac puncture using a syringe primed with heparin sulfate. Pharmacokinetic analysis of plasma and generation of tumor lysates were performed as described.30 IP/W analysis was performed as described for in vitro experiments. Bone marrow model. NOD-SCID mice were pretreated with cyclophosphamide (Neosar, Pharmacia, Kalamazoo, MI) by intraperitoneal injection of 150 mg/kg/d for 2 days,33 followed by 24 hours of rest prior to intravenous injection of 5 × 106 cells via the tail vein. At experimental end points (within 90 days of implantation) mice were anesthetized, followed by terminal blood collection via intracardiac puncture. Bone marrow cell suspensions were prepared by flushing mouse femurs with cold, sterile PBS. A range of doses of SU11248 or its vehicle were orally administered once daily, as indicated in figure and table legends. For all studies, a paired Student t test was used to assess differences between treated and control groups (P < .05 was considered significant). Flow cytometric analysis. For flow cytometric analysis of bone marrow samples, erythrocytes were lysed using Cal-Lyse (Caltag Laboratories, Burlingame, CA) following the manufacturer's protocol. The percentage of human cells in bone marrow was determined by staining with phycoerythrin-conjugated antihuman CD45 (Pharmingen, San Diego, CA) and isotype controls. Samples were analyzed on a Becton Dickinson FACSCalibur flow cytometer. Data analysis was performed using CellQuest. Histopathology and IHC. Sections were prepared from formalin-fixed, decalcified, and paraffin-embedded mouse tibias. General tissue morphology and microvessels were visualized using conventional hematoxylin and eosin (H&E) staining. Cell proliferation was visualized using the MIB-1 monoclonal antibody for Ki-67 (Immunotech, Westbrook, ME) and biotinylated polyclonal rabbit antimouse secondary antibody (Zymed, South San Francisco, CA), using a peroxidase-based immunostaining protocol (Vectastain ABC Elite kit, Vector Laboratories, Burlingame, CA).
SU11248 inhibits FLT3-WT, FLT3-ITD, and FLT3-Asp835 mutant phosphorylation SU11248 was designed to have broad selectivity for the split kinase family of RTKs and potently inhibits PDGFR , PDGFR , VEGFR2 (KDR), VEGFR1 (FLT1), and KIT, as recently described.30
Given the sequence conservation between FLT3 and other members of the class III RTK family, we reasoned that SU11248 may also inhibit FLT3.
To investigate SU11248 activity, cellular assays to detect changes in
FLT3 phosphorylation were performed using leukemia cell lines RS;411
(which expresses wild-type FLT3) and MV4;11 (which expresses FLT3-ITD
mutant).31 For both cell lines, IP/W analysis
showed 2 forms of FLT3 protein, a higher ( 160 kDa) and lower (135 kDa) molecular weight form that likely correspond to mature and
immature forms of FLT3 expressed on the cell surface and
intracellularly, respectively.2 In RS4;11 cells (FLT3-WT), addition of FL was necessary to stimulate FLT3 phosphorylation, and, as
predicted, primarily the higher molecular weight (likely extracellular)
FLT3 species was phosphorylated. As shown in Figure 1A, treatment with SU11248 inhibited
FLT3-WT phosphorylation in a dose-dependent manner with a 50%
inhibitory concentration (IC50) of approximately
250 nM. Similar results were obtained in the OC1-AML5 human leukemia
cell line, which also expresses FLT3-WT, as assessed by genotyping
(data not shown). In MV4;11 cells that express FLT3-ITD, it is
noteworthy that both high and low molecular weight forms of FLT3 are
phosphorylated in the absence of FLT3 ligand (FL), consistent with
expression of FLT3-ITD (Figure 1B). SU11248 inhibited FLT3-ITD
phosphorylation in a dose-dependent manner with an IC50 of
50 nM following a 2-hour treatment (Figure 1B). In 5 separate
experiments, IC50 values ranged from 10 to 60 nM for
FLT3-ITD, with a mean of 50 nM (data not shown).
To address whether the apparent difference in sensitivity of FLT3-WT and FLT3-ITD to SU11248 could be attributed to use of these nonisogenic cell lines, a 32D myeloid cell line engineered to express FLT3-WT or FLT3-ITD5 was tested. SU11248 inhibited 32D:FLT3-WT phosphorylation with an IC50 of approximately 250 nM; while 32D:FLT3-ITD was inhibited with an IC50 of 50 nM (data not shown). These cell lines showed similar levels of FLT3 cell surface staining when assessed by flow cytometry analysis. It therefore appears that FLT3-ITD has increased sensitivity to SU11248 relative to FLT3-WT. We also investigated the activity of SU11248 against FLT3 activation
loop mutations using transiently transfected CHO cells. For CHO cells
expressing FLT3-WT, treatment with FLT3 ligand stimulated phosphorylation, and SU11248 inhibited phosphorylation with an IC50 of approximately 30 nM (Figure
2). FLT3 was constitutively phosphorylated in all cells expressing mutant FLT3. SU11248 inhibited phosphorylation of FLT3-ITD with an IC50 of less
than 10 nM. Similarly, phosphorylation of activation loop
mutants Asp835Tyr, Asp835Val, and Asp835His was inhibited by SU11248,
with IC50 values of 30 to 300 nM (Figure 2). Taken together
these data demonstrate that SU11248 inhibits phosphorylation of
FLT3-WT, FLT3-ITD, and FLT3-Asp835 mutant forms of FLT3.
SU11248 inhibits proliferation induced by FLT3-ITD and FLT3-WT Having demonstrated that SU11248 inhibits FLT3 phosphorylation, the biologic consequence of inhibition was tested in cell proliferation and apoptosis assays. For the FLT3-ITD cell line MV4;11, SU11248 dramatically inhibited cellular proliferation in a dose-dependent manner with an IC50 of 1 to 10 nM (Figure 3A). We used the factor-dependent FLT3-WT cell line, OC1-AML5, to investigate the effect of SU11248 on proliferation driven by FLT3-WT. Addition of FL stimulated an approximately 3-fold increase in OC1-AML5 cell number over 48 hours (data not shown). SU11248 inhibited proliferation of OC1-AML5 with an IC50 of approximately 10 nM in the presence of FLT3 ligand (Figure 3A). The mean IC50 values for inhibition of proliferation of MV4;11 and OC1-AML5 cells at 48 hours were 8 nM and 14 nM, respectively, in at least 3 independent experiments. Similar results were apparent in trypan blue viable cell count assays, in which SU11248 inhibited expansion of MV4;11 and OC1-AML5 cell lines in a dose-dependent manner, with IC50 values in the 10 to 50 nM range. RS4;11 cells (FLT3-WT) are not factor-dependent and addition of FLT3 ligand induced only a modest increase in proliferation. Accordingly SU11248 inhibited FLT3 ligand-stimulated proliferation in RS4;11 cells with an IC50 of more than 500 nM (data not shown).
Next the ability of SU11248 to induce apoptosis was assessed using measurement of PARP cleavage and caspase-3 levels as indicators. For FLT3-ITD-expressing cells (MV4;11) a low level of cleaved PARP was evident at baseline. Addition of SU11248 increased PARP cleavage (89-kDa and 24-kDa fragments) in a dose-dependent manner, evident at 10 nM SU11248, with a concomitant decrease in full-length PARP (Figure 3B). Similarly, a dose-dependent increase in levels of the proteolytic (active) fragment of caspase-3 was observed in the presence of SU11248 (Figure 3D). Similar observations were made using FACS analysis for active caspase-3 (data not shown). For OC1-AML5 cells, cleaved PARP and caspase-3 were evident within a similar dose range (Figure 3C,E), although the magnitude of cell death in cultures was less than MV4;11 cells. RS4;11 cells did not undergo apoptosis in the presence of SU11248, consistent with a lack of dependence on FLT3 for survival (data not shown). Taken together, these data suggest that SU11248 inhibits proliferation driven by both FLT3-WT and FLT3-ITD, resulting in apoptosis. SU11248 causes dramatic regression of large subcutaneous FLT3-ITD tumors in athymic mice Having determined that SU11248 is a potent inhibitor of FLT3 in vitro, we evaluated the in vivo activity of this compound using a FLT3-ITD tumor model. Subcutaneous implantation of MV4;11 cells expressing FLT3-ITD into athymic mice resulted in growth of solid tumors of approximately 500 mm3 within 4 weeks; tumors continued to increase in size until mice were killed. Immunohistochemical staining for Ki67 demonstrated a high proliferation index, consistent with the rapid tumor growth rate. In addition strong FLT3 expression on tumor cells was observed (data not shown).We previously reported that SU11248 dosed orally at 40 mg/kg/d is fully
efficacious in a number of subcutaneous tumor xenograft models,
including SF763T and Colo205.30 Therefore, the 40 mg/kg/d dose was initially tested for efficacy in mice bearing established MV4;11 tumors of approximately 300 to 500 mm3. SU11248
treatment resulted in a dramatic destruction of the tumor with visual
disappearance 4 days after treatment in all mice (n = 10) (Figure
4A). Daily administration of SU11248 was ceased 8 days after full regression was observed to determine if the effect of SU11248 was reversible. This resulted in eventual regrowth of 6 of 10 tumors, with no regrowth in the remaining 4 (2 of
which were observed for 10 months after treatment stopped). Of
the regrowing tumors, 4 were again treated with 40 mg/kg/d of SU11248
when they reached approximately 2000 mm3. All of these
tumors responded dramatically to the second treatment with 40 mg/kg of
daily SU11248, suggesting that tumors had not developed resistance
(Figure 4B).
When tumors from the vehicle control group in Figure 4A reached approximately 2000 mm3, these mice were treated with SU11248, resulting in complete tumor regression. Dosing was ceased after an average of 23 days of treatment. Of 10 mice, 2 exhibited tumor regrowth, while 8 mice exhibited no regrowth after 2.5 months (2 of which are still viable and remain tumor-free after 9 months). Daily treatment with SU11248 was well tolerated, with no signs of gross toxicity. The rapid regression of the FLT3-ITD-expressing cell line MV4;11 by SU11248 is consistent with dependence on constitutive FLT3 signaling for survival. Since 40 mg/kg/d of SU11248 caused profound tumor regression, lower daily doses of SU11248 (20, 5, and 1 mg/kg/d) were evaluated to determine the lowest efficacious dose. In mice receiving 20 mg/kg/d of SU11248, complete tumor regression was apparent although not as rapidly as observed with the 40 mg/kg/d dose (Figure 4C). For the lower dose of 5 mg/kg/d, a marginal but insignificant effect on tumor growth was apparent, and 1 mg/kg/d had no effect. In a separate study a 10 mg/kg dose induced tumor growth inhibition but not regression (data not shown). These efficacy studies confirm dose-dependent inhibition of tumor growth by SU11248 and demonstrate that 20 mg/kg/d is the minimal efficacious dose to induce regression. To assess FLT3 phosphorylation in tumor cells, tumor (MV4;11)-bearing mice were treated with vehicle control or a single dose of SU11248 (40 mg/kg). Analysis of FLT3 phosphorylation by IP/W showed high levels of phosphorylation in tumor lysates from predose (untreated) or vehicle-treated animals (n = 3 per group). FLT3 protein levels were not altered by SU11248 but FLT3 phosphorylation was dramatically suppressed in all SU11248-treated animals within 4 hours (Figure 4D). Analysis of a downstream FLT3-ITD signaling protein, Stat5, showed similarly decreased phosphorylation; Stat5 was highly activated at baseline in both vehicle and untreated animals and markedly inhibited by a single administration of SU11248 (Figure 4D). Establishment of pharmacokinetic and pharmacodynamic (PK/PD) relationship for FLT3-ITD inhibition in vivo Establishment of a PK/PD relationship is an important aspect for translation of preclinical data to clinical trials. We have reported that SU11248 exhibits predictable and dose-dependent pharmacokinetics in mice.30 To define the PK/PD relationship for SU11248 in modulation of FLT3-ITD in vivo, we first addressed the kinetics of inhibition of FLT3 phosphorylation at 20 mg/kg SU11248, the lowest dose inducing tumor regression. After a single dose of SU11248, tumors were removed at various time points for analysis of FLT3 phosphorylation, and plasma was simultaneously collected for analysis of drug levels. The single SU11248 administration completely inhibited FLT3 phosphorylation within 2 hours, for at least 12 to 16 hours (Figure 5A). At 24 and 48 hours, phosphorylation increased, although levels remained lower than those observed in tumors from untreated animals. Plasma inhibitor levels are indicated in Figure 5 and showed expected concentrations and kinetics: a dose of 20 mg/kg produced a maximal concentration (Cmax) of more than 100 ng/mL ( 250 nM) within 2 hours and plasma drug levels were less than 1 ng/mL at 16 hours after dosing. The observed inhibition of FLT3 phosphorylation at 12 and 16 hours, when plasma drug
levels were less than 1 ng/mL, may reflect the duration of FLT3
inhibition once target plasma concentration is attained
(below).
Next, the effects of subefficacious (5 mg/kg) and nonefficacious (1 mg/kg) doses of SU11248 were examined at 2, 4, and 8 hours after administration, as shown in Figure 5B. A single dose of SU11248 at 5 mg/kg inhibited FLT3 phosphorylation at 2 hours with less inhibition at 4 and 8 hours. Inhibition was weaker and more transient than that observed with 20 mg/kg (Figure 5B). The nonefficacious dose of 1 mg/kg marginally inhibited FLT3 phosphorylation. Quantitation of Western blots using Quantity One software (BioRad, Hercules, CA) supported these observations (data not shown). It therefore appears that strong (> 50%) inhibition of FLT3-ITD phosphorylation maintained for 8 to 16 hours correlates with regression in this model. Additional PK/PD analysis comparing different drug doses suggested that a target plasma concentration of 30 to 50 ng/mL for at least 8 hours correlated with robust sustained inhibition of FLT3-ITD, attained with 20 mg/kg and not with 5 mg/kg. This is slightly lower than, but in a similar range to, that predicted for PDGFR and Flk-1 (50-100 ng/mL).30 These data show that inhibition of FLT3-ITD phosphorylation by SU11248 is dose-dependent, and the magnitude and extent of FLT3 inhibition at 1, 5, and 20 mg/kg correlate with results of the efficacy experiments. SU11248 enhances survival in a bone marrow engraftment model Having shown that SU11248 regresses FLT3-ITD tumors in a subcutaneous tumor model, we investigated the effects of SU11248 in a more physiologically relevant leukemia model in which cells engraft in the bone marrow, established using MV4;11 cells. Mice were sublethally pretreated with cyclophosphamide33 to reduce the endogenous bone marrow cell population and facilitate engraftment before intravenous injection of 5 × 106 MV4;11 cells. Flow cytometric analysis of human CD45 expression in bone marrow was performed to provide evidence of disease. Human cells were detectable in bone marrow approximately 4 weeks after cell inoculation. Clinically, within 40 to 50 days mice exhibited hind limb paralysis, ruffled fur, and decreased spontaneous activity (grooming and ambulation).To study the effect of SU11248 on survival, once-daily treatment with
either SU11248 or vehicle was initiated 3 weeks after MV4;11 cell
implantation. Animals were continued on the assigned SU11248 or vehicle
treatment regimen until sufficient clinical evidence of symptomatic
disease progression (eg, hind limb paralysis or morbidity) was present
to warrant humane killing. All vehicle control group mice died
within 39 to 50 days, with a mean survival time of 41 days (Figure
6A). Mice on the SU11248 arm demonstrated prolonged dose-dependent survival. With 5, 10, and 20 mg/kg/d of orally
administered SU11248, the mean survival time was significantly prolonged to 46, 56, and at least 83 days, respectively
(P = .002, P < .0001,
P < .0001, respectively). Accompanying the increase in
survival time, SU11248-treated mice demonstrated a marked lack of hind
limb paralysis, a healthier-appearing coat, and more normal levels of
physical activity, while the vehicle-treated mice had succumbed to
disease. FACS analysis showed that vehicle-treated animals had an
average of 49% human CD45+ cells in bone marrow (range,
19%-73%) while SU11248-treated mice had an average of 2.3% (Figure
6B). In control mice pretreated with cyclophosphamide but not
inoculated with MV4;11 cells, less than 1% human CD45+
cells were detected in the bone marrow.
Morphologic examination of H&E-stained bone marrow sections from untreated or vehicle-treated animals showed large cells with pale nuclei and abundant mitotic figures in locally abundant regions as well as diffuse infiltration (Figure 6C). MV4;11 cells had strong nuclear immunoreactivity for Ki67, while other cells stained weakly. Bone marrow from MV4;11-inoculated mice also appeared highly vascularized (data not shown). Treatment with SU11248 at 20 mg/kg/d resulted in reduced numbers of bone marrow MV4;11 cells when examined on day 50. In some cases, only a few leukemic cells distributed throughout the bone marrow remained, while other samples exhibited no evidence of leukemic cells, which correlated with lack of overt disease symptoms (Figure 6C). These data show that SU11248 has efficacy in a FLT3-ITD model of lethal bone marrow disease, with similar dose-dependence to the subcutaneous model. SU11248 decreases VEGF levels following FLT3 signaling Increased microvessel density and increased VEGFR2 expression26,27 has been reported in bone marrow of AML patients, relative to healthy donors, and it has been proposed that paracrine growth stimulatory interactions occur between blasts and endothelial cells.29 VEGF binding to its receptor KDR (VEGFR2, Flk-1) is one of the best-characterized positive inducers of tumor neovascularization by the stimulation of endothelial cell proliferation and migration34 (for reviews see Ferrara and Gerber35; Albitar36; and Rosen37). To assess the effects of FLT3-ITD signaling on VEGF production, we measured VEGF levels in tissue culture supernatants from cell lines. MV4;11 (FLT3-ITD) cells constitutively produced relatively high levels of VEGF, ranging from 35 to 92 pg/mL per 105 cells. Culture in the presence of SU11248 inhibited VEGF production in a dose-dependent manner with an IC50 of approximately 10 nM (Table 1). When VEGF levels were normalized for viable cell number the inhibitory effect was still apparent, suggesting that the reduced VEGF levels are not simply a reflection of decreased cell number in the presence of SU11248, but more likely due to decreased signaling in viable cells. To assess if VEGF production is specific to leukemia cell lines, similar experiments were performed in 32D:FLT3-ITD cells and murine VEGF was measured. We observed that 32D:FLT3-ITD cells constitutively produced VEGF (data not shown).
Analysis of FLT3-WT cells showed that VEGF was barely detectable in 72-hour culture supernatants from RS4;11 cells (< 1 pg/mL per 105 cells), while OC1-AML5 cells produced low levels (32 pg/mL per 105 cells). However addition of FLT3 ligand increased VEGF production by 3- to 4-fold in each cell line, and this effect was inhibited by SU11248 (Table 1). We also measured human VEGF levels in plasma from a survival study in the MV4;11 bone marrow engraftment model. In naive mice (n = 4) VEGF was not detected. In MV4;11-inoculated mice with hind limb paralysis treated with vehicle, VEGF was detectable in 9 of 9 cases (mean 49 pg/mL, range). VEGF was not detected in any of 6 apparently healthy MV4;11-inoculated mice treated with SU11248 at 20 mg/kg daily. These data suggest that signaling downstream of both FLT3-WT and FLT3-ITD results in VEGF production, which is inhibited by SU11248. VEGF is a potential marker for FLT3-ITD in vivo.
AML is a malignant disorder of hematopoietic progenitor cells and constitutes approximately 90% of adult acute leukemia. As the vast majority of adults who develop AML eventually succumb to their disease or associated cytotoxic therapy, there is an urgent need for new therapies. The FLT3-ITD mutation is the most common molecular defect in AML and confers poor prognosis. In this report we have characterized SU11248 as a FLT3 inhibitor. We show that SU11248 inhibits phosphorylation of FLT3-ITD, FLT3-Asp835, as well as FLT3-WT, which results in inhibition of proliferation and induction of apoptosis in vitro. Consistent with these observations, SU11248 had dramatic efficacy in a FLT3-ITD xenograft model and also in a bone marrow engraftment model. Analysis of SU11248 effects on FLT3-ITD phosphorylation in tumor xenografts showed a time- and dose-dependent inhibition of phosphorylation, and a PK/PD relationship was established. Finally, SU11248 treatment can abrogate VEGF production, secondary to FLT3 signaling. In cellular assays, SU11248 potently inhibited FLT3-ITD phosphorylation with an IC50 of 50 nM, similar to those reported for other RTK targets of SU11248.30 SU11248 exhibited a relative increase in potency for inhibition of FLT3-ITD phosphorylation relative to FLT3-WT when assayed in different cell lines that express either endogenous or overexpressed FLT3 and also when assayed in transiently transfected CHO cells. There are several possibilities to account for this effect: SU11248 may bind to FLT3-ITD with increased affinity due to differences in conformation between WT and ITD; accessibility to drug may be influenced by differences in cellular localization; or levels of ligand necessary to stimulate phosphorylation of FLT3-WT in vitro may be nonphysiologic. Irrespective of the mechanism, our data demonstrate that SU11248 inhibits phosphorylation of both mutant FLT3 and FLT3-WT, and may have an increased potency for FLT3-ITD relative to FLT3-WT. SU11248 also inhibited phosphorylation of Asp835 point mutations, Asp835Val, Asp835His, and Asp835Tyr. As anticipated, the biologic consequences of FLT3 inhibition were most profound in MV4;11 cells where FLT3-ITD appears to drive proliferation. Proliferation was inhibited by SU11248 with an IC50 of 1 to 10 nM, resulting in apoptosis. SU11248 also inhibited FL-driven proliferation in the FLT3-WT cell line OC1-AML5, most likely because this cell line undergoes apoptosis in the absence of added cytokines and FL maintains survival. It is unlikely that the effects of SU11248 on MV4;11 cells are mediated by targeting other RTKs, as MV4;11 cells do not appear to express PDGFR; and while weak expression of KIT was detected, no phosphorylation was apparent in IP/W experiments (data not shown). SU11248 inhibited FLT3 phosphorylation in RS4;11 cells, but this cell line is more than 100-fold less sensitive to SU11248 than MV4;11 in biologic assays. This can be attributed to the lack of requirement for FLT3 signaling for survival or proliferation in RS4;11, and also demonstrates that SU11248 does not have nonspecific effects. These data are consistent with observations of Levis et al38 who reported that FLT3 phosphorylation was inhibited by CEP-701, a different FLT3 inhibitor, in the BV173 cell line, but cells did not undergo apoptosis. It is likely that inhibition of additional signaling pathways is necessary to elicit a cytotoxic response in RS4;11. A subcutaneous tumor xenograft model was used to assess the effects of
SU11248 in vivo and to help define the PK/PD relationship for FLT3-ITD,
important for the translation of this compound to clinical testing. We
found that SU11248 dramatically regressed FLT3-ITD xenografts in a
dose-dependent manner, with a minimum fully efficacious dose of 20 mg/kg/d most likely acting as a direct antitumor agent. This dose is
lower than that identified for inhibition of other human tumor cell
line xenografts such as SF763T and Colo205 (40 mg/kg/d). In these
models SU11248 may act primarily as an antiangiogenic
agent,30 targeting VEGFR2/KDR and PDGFR expressed in tumor
endothelium and/or stroma. Since SU11248 does not have increased
potency against FLT3 in cellular phosphorylation assays relative to
PDGFR or VEGFR2 (IC50 approximately 10 nM for PDGFR The target genes of FLT3 signaling pathways that function in oncogenesis have not been identified. We report the novel finding that FLT3 signaling leads to secretion of VEGF in vitro, most notably in FLT3-ITD cell lines. It seems likely that VEGF is a direct rather than indirect target of FLT3 signal transduction pathways, given that this effect was apparent in several cell lines and also apparent following FLT3-WT stimulation. A mechanism may exist in AML by which FLT3-induced VEGF contributes to bone marrow angiogenesis in a paracrine fashion and has autocrine action on blast cells. It will be of significance to determine whether blasts from FLT3-ITD-positive AML patients express higher levels of VEGF than those of FLT3-WT patients. The prognostic significance of FLT3-ITD mutations in clinical studies suggests that FLT3 plays a driving role in AML. Recent evidence in mouse models suggests that FLT3-ITD mutations alone induce myeloproliferative disease, whereas additional mutations are needed to induce AML.15,16 In addition to SU11248, several other small-molecule FLT3 inhibitors have been recently described, including AG1295,39 PKC412,40 CT53518,41 CEP701,38 SU5416,31 and MLN518.42 Each has a unique spectrum of activity for other kinases including VEGFR2, PDGFR, KIT, protein kinase C (PKC), and tyrosine kinase (TRK). Additional strategies to target FLT3 have also been defined, such as use of HSP90 inhibitors.43 SU11248 is orally bioavailable, can exert direct tumor inhibition by targeting FLT3 on blasts, and also has potent activity against PDGFR and VEGFR, which regulate angiogenesis, associated with disease progression. The demonstration that SU11248 exhibits sustained target inhibition and efficacy in FLT3-ITD models suggests that this compound may have biologic activity in AML. SU11248 is currently in phase 1 AML clinical trials.
We are very grateful to Dr Hubert Serve for providing the FLT3-expressing 32D cell lines. We would like to acknowledge Dr Alison Hannah for critical review of this manuscript, group members for useful discussions, and Barbara Remley for help with manuscript preparation.
Submitted July 31, 2002; accepted November 14, 2002.
Prepublished online as Blood First Edition Paper, January 16, 2003; DOI 10.1182/blood-2002-07-2307.
Supported by a Merit Review Grant from the Department of Veterans Affairs (M.C.H.).
The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked "advertisement" in accordance with 18 U.S.C. section 1734.
Reprints: Anne-Marie O'Farrell, SUGEN, 230 E Grand Ave, South San Francisco, CA 94080; e-mail: marie-ofarrell{at}sugen.com.
1. Rosnet O, Marchetto S, deLapeyriere O, Birnbaum D. Murine Flt3, a gene encoding a novel tyrosine kinase receptor of the PDGFR/CSF1R family. Oncogene. 1991;6:1641-1650[Medline] [Order article via Infotrieve]. 2. Maroc N, Rottapel R, Rosnet O, et al. Biochemical characterization and analysis of the transforming potential of the FLT3/FLK2 receptor tyrosine kinase. Oncogene. 1993;8:909-918[Medline] [Order article via Infotrieve]. 3. Rosnet O, Buhring HJ, deLapeyriere O, et al. Expression and signal transduction of the FLT3 tyrosine kinase receptor. Acta Haematol. 1996;95:218-223[Medline] [Order article via Infotrieve]. 4. Hayakawa F, Towatari M, Kiyoi H, et al. Tandem-duplicated Flt3 constitutively activates STAT5 and MAP kinase and introduces autonomous cell growth in IL-3-dependent cell lines. Oncogene. 2000;19:624-631[CrossRef][Medline] [Order article via Infotrieve].
5.
Mizuki M, Fenski R, Halfter H, et al.
Flt3 mutations from patients with acute myeloid leukemia induce transformation of 32D cells mediated by the Ras and STAT5 pathways.
Blood.
2000;96:3907-3914 6. Zhang S, Broxmeyer HE. p85 subunit of PI3 kinase does not bind to human FLT3 receptor, but associates with SHP2, SHIP, and a tyrosine-phosphorylated 100-kDa protein in FLT3 ligand-stimulated hematopoietic cells. Biochem Biophys Res Commun. 1999;254:440-445[CrossRef][Medline] [Order article via Infotrieve].
7.
Hudak S, Hunte B, Culpepper J, et al.
FLT3/FLK2 ligand promotes the growth of murine stem cells and the expansion of colony-forming cells and spleen colony-forming units.
Blood.
1995;85:2747-2755
8.
Piacibello W, Fubini L, Sanavio F, et al.
Effects of human FLT3 ligand on myeloid leukemia cell growth: heterogeneity in response and synergy with other hematopoietic growth factors.
Blood.
1995;86:4105-4114 9. Mackarehtschian K, Hardin JD, Moore KA, Boast S, Goff SP, Lemischka IR. Targeted disruption of the flk2/flt3 gene leads to deficiencies in primitive hematopoietic progenitors. Immunity. 1995;3:147-161[CrossRef][Medline] [Order article via Infotrieve].
10.
Carow CE, Levenstein M, Kaufmann SH, et al.
Expression of the hematopoietic growth factor receptor FLT3 (STK-1/Flk2) in human leukemias.
Blood.
1996;87:1089-1096 11. Drexler HG. Expression of FLT3 receptor and response to FLT3 ligand by leukemic cells. Leukemia. 1996;10:588-599[Medline] [Order article via Infotrieve]. 12. Stacchini A, Fubini L, Severino A, Sanavio F, Aglietta M, Piacibello W. Expression of type III receptor tyrosine kinases FLT3 and KIT and responses to their ligands by acute myeloid leukemia blasts. Leukemia. 1996;10:1584-1591[Medline] [Order article via Infotrieve]. 13. Gilliland DG, Griffin JD. Role of FLT3 in leukemia. Curr Opin Hematol. 2002;9:274-281[CrossRef][Medline] [Order article via Infotrieve]. 14. Tse KF, Mukherjee G, Small D. Constitutive activation of FLT3 stimulates multiple intracellular signal transducers and results in transformation. Leukemia. 2000;14:1766-1776[CrossRef][Medline] [Order article via Infotrieve].
15.
Kelly LM, Liu Q, Kutok JL, Williams IR, Boulton CL, Gilliland DG.
FLT3 internal tandem duplication mutations associated with human acute myeloid leukemias induce myeloproliferative disease in a murine bone marrow transplant model.
Blood.
2002;99:310-318
16.
Kelly LM, Kutok JL, Williams IR, et al.
PML/RARalpha and FLT3-ITD induce an APL-like disease in a mouse model.
Proc Natl Acad Sci U S A.
2002;99:8283-8288 17. Nakao M, Yokota S, Iwai T, et al. Internal tandem duplication of the flt3 gene found in acute myeloid leukemia. Leukemia. 1996;10:1911-1918[Medline] [Order article via Infotrieve].
18.
Kiyoi H, Naoe T, Nakano Y, et al.
Prognostic implication of FLT3 and N-RAS gene mutations in acute myeloid leukemia.
Blood.
1999;93:3074-3080 19. Kondo M, Horibe K, Takahashi Y, et al. Prognostic value of internal tandem duplication of the FLT3 gene in childhood acute myelogenous leukemia. Med Pediatr Oncol. 1999;33:525-529[CrossRef][Medline] [Order article via Infotrieve].
20.
Stirewalt DL, Kopecky KJ, Meshinchi S, et al.
FLT3, RAS, and TP53 mutations in elderly patients with acute myeloid leukemia.
Blood.
2001;97:3589-3595 21. Abu-Duhier FM, Goodeve AC, Wilson GA, et al. FLT3 internal tandem duplication mutations in adult acute myeloid leukaemia define a high-risk group. Br J Haematol. 2000;111:190-195[CrossRef][Medline] [Order article via Infotrieve].
22.
Kottaridis PD, Gale RE, Frew ME, et al.
The presence of a FLT3 internal tandem duplication in patients with acute myeloid leukemia (AML) adds important prognostic information to cytogenetic risk group and response to the first cycle of chemotherapy: analysis of 854 patients from the United Kingdom Medical Research Council AML 10 and 12 trials.
Blood.
2001;98:1752-1759
23.
Meshinchi S, Woods WG, Stirewalt DL, et al.
Prevalence and prognostic significance of Flt3 internal tandem duplication in pediatric acute myeloid leukemia.
Blood.
2001;97:89-94
24.
Thiede C, Steudel C, Mohr B, et al.
Analysis of FLT3-activating mutations in 979 patients with acute myelogenous leukemia: association with FAB subtypes and identification of subgroups with poor prognosis.
Blood.
2002;99:4326-4335
25.
Yamamoto Y, Kiyoi H, Nakano Y, et al.
Activating mutation of D835 within the activation loop of FLT3 in human hematologic malignancies.
Blood.
2001;97:2434-2439
26.
Padro T, Ruiz S, Bieker R, et al.
Increased angiogenesis in the bone marrow of patients with acute myeloid leukemia.
Blood.
2000;95:2637-2644 27. Padro T, Bieker R, Ruiz S, et al. Overexpression of vascular endothelial growth factor (VEGF) and its cellular receptor KDR (VEGFR-2) in the bone marrow of patients with acute myeloid leukemia. Leukemia. 2002;16:1302-1310[CrossRef][Medline] [Order article via Infotrieve].
28.
Aguayo A, Estey E, Kantarjian H, et al.
Cellular vascular endothelial growth factor is a predictor of outcome in patients with acute myeloid leukemia.
Blood.
1999;94:3717-3721 29. Fiedler W, Staib P, Kuse R, et al. Role of angiogenesis inhibitors in acute myeloid leukemia. Cancer J. 2001;7(suppl 3):S129-S133.
30.
Mendel DB, Laird AD, Xin X, et al.
In vivo anti-tumor activity of SU11248, a novel tyrosine kinase inhibitor targeting VEGF and PDGF receptors: determination of a pharmacokinetic/pharmacodynamic relationship.
Clin Canc Res.
2003;9:327-337
31.
Yee KW, O'Farrell AM, Smolich BD, et al.
SU5416 and SU5614 inhibit kinase activity of wild-type and mutant FLT3 receptor tyrosine kinase.
Blood.
2002;100:2941-2949 32. Institute of Laboratory Animal Resources Commission on Life Sciences. Guide for the Care and Use of Laboratory Animals. Washington, DC: National Academy Press.; 1996. 33. Cesano A, Hoxie JA, Lange B, Nowell PC, Bishop J, Santoli D. The severe immunodeficient (SCID) mouse as a model for human myeloid leukemias. Oncogene. 1992;5:827-836.
34.
Leung DW, Cachianes G, Kuang WJ, Goeddel DV, Ferrara N.
Vascular endothelial growth factor is a secreted angiogenic mitogen.
Science.
1989;246:1306-1309 35. Ferrara N, Gerber HP. The role of vascular endothelial growth factor in angiogenesis. Acta Haematol. 2001;106:148-156[CrossRef][Medline] [Order article via Infotrieve]. 36. Albitar M. Angiogenesis in acute myeloid leukemia and myelodysplastic syndrome. Acta Haematol. 2001;106:170-176[CrossRef][Medline] [Order article via Infotrieve]. 37. Rosen LS. Clinical experience with angiogenesis signaling inhibitors: focus on vascular endothelial growth factor (VEGF) blockers. Cancer Control. 2002;9(suppl 2):36-44[Medline] [Order article via Infotrieve].
38.
Levis M, Allebach J, Tse KF, et al.
A FLT3-targeted tyrosine kinase inhibitor is cytotoxic to leukemia cells in vitro and in vivo.
Blood.
2002;99:3885-3891
39.
Levis M, Tse KF, Smith BD, Garrett E, Small D.
A FLT3 tyrosine kinase inhibitor is selectively cytotoxic to acute myeloid leukemia blasts harboring FLT3 internal tandem duplication mutations.
Blood.
2001;98:885-887 40. Weisberg E, Boulton C, Kelly LM, et al. Inhibition of mutant FLT3 receptors in leukemia cells by the small molecule tyrosine kinase inhibitor PKC412. Cancer Cell. 2002;5:433-443. 41. Kelly LM, Yu JC, Boulton CL, et al. CT53518, a novel selective FLT3 antagonist for the treatment of acute myelogenous leukemia (AML). Cancer Cell. 2002;1:421-432[CrossRef][Medline] [Order article via Infotrieve]. 42. Heinrich MC, Drucker BJ, Curtin PT, et al. A "First in Man" study of the safety and PK/PD of an oral FLT3 inhibitor (MLN518) in patients with AML or high risk myelodysplasia. Blood. 2002;100:1305. 43. Minami Y, Kiyoi H, Yamamoto Y, et al. Selective apoptosis of tandemly duplicated FLT3-transformed leukemia cells by Hsp90 inhibitors. Leukemia. 2002;16:1535-1540[CrossRef][Medline] [Order article via Infotrieve].
© 2003 by The American Society of Hematology.
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|
  JNJ-28312141, a novel orally active colony-stimulating factor-1 receptor/FMS-related receptor tyrosine kinase-3 receptor tyrosine kinase inhibitor with potential utility in solid tumors, bone metastases, and acute myeloid leukemia Mol. Cancer Ther., November 1, 2009; 8(11): 3151 - 3161.
|
|
|
|
 |
|
 P. P. Zarrinkar, R. N. Gunawardane, M. D. Cramer, M. F. Gardner, D. Brigham, B. Belli, M. W. Karaman, K. W. Pratz, G. Pallares, Q. Chao, et al. AC220 is a uniquely potent and selective inhibitor of FLT3 for the treatment of acute myeloid leukemia (AML) Blood, October 1, 2009; 114(14): 2984 - 2992. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. D. Demetri, M. C. Heinrich, J. A. Fletcher, C. D.M. Fletcher, A. D. Van den Abbeele, C. L. Corless, C. R. Antonescu, S. George, J. A. Morgan, M. H. Chen, et al. Molecular Target Modulation, Imaging, and Clinical Evaluation of Gastrointestinal Stromal Tumor Patients Treated with Sunitinib Malate after Imatinib Failure Clin. Cancer Res., September 15, 2009; 15(18): 5902 - 5909. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. E. DePrimo, X. Huang, M. E. Blackstein, C. R. Garrett, C. S. Harmon, P. Schoffski, M. H. Shah, J. Verweij, C. M. Baum, and G. D. Demetri Circulating Levels of Soluble KIT Serve as a Biomarker for Clinical Outcome in Gastrointestinal Stromal Tumor Patients Receiving Sunitinib following Imatinib Failure Clin. Cancer Res., September 15, 2009; 15(18): 5869 - 5877. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Escudier, J. Roigas, S. Gillessen, U. Harmenberg, S. Srinivas, S. F. Mulder, G. Fountzilas, C. Peschel, P. Flodgren, E. C. Maneval, et al. Phase II Study of Sunitinib Administered in a Continuous Once-Daily Dosing Regimen in Patients With Cytokine-Refractory Metastatic Renal Cell Carcinoma J. Clin. Oncol., September 1, 2009; 27(25): 4068 - 4075. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Darrasse-Jeze, S. Deroubaix, H. Mouquet, G. D. Victora, T. Eisenreich, K.-h. Yao, R. F. Masilamani, M. L. Dustin, A. Rudensky, K. Liu, et al. Feedback control of regulatory T cell homeostasis by dendritic cells in vivo J. Exp. Med., August 31, 2009; 206(9): 1853 - 1862. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-Y. Blay Pharmacological management of gastrointestinal stromal tumours: an update on the role of sunitinib Ann. Onc., August 12, 2009; (2009) mdp291v1. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Bao, C.-J. Lai, H. Qu, D. Wang, L. Yin, B. Zifcak, R. Atoyan, J. Wang, M. Samson, J. Forrester, et al. CUDC-305, a Novel Synthetic HSP90 Inhibitor with Unique Pharmacologic Properties for Cancer Therapy Clin. Cancer Res., June 15, 2009; 15(12): 4046 - 4057. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Castillo-Avila, J. M. Piulats, X. Garcia del Muro, A. Vidal, E. Condom, O. Casanovas, J. Mora, J. R. Germa, G. Capella, A. Villanueva, et al. Sunitinib Inhibits Tumor Growth and Synergizes with Cisplatin in Orthotopic Models of Cisplatin-Sensitive and Cisplatin-Resistant Human Testicular Germ Cell Tumors Clin. Cancer Res., May 15, 2009; 15(10): 3384 - 3395. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Burkitt, S. Y. Chun, D. T. Dang, and L. H. Dang Targeting both HIF-1 and HIF-2 in human colon cancer cells improves tumor response to sunitinib treatment Mol. Cancer Ther., May 1, 2009; 8(5): 1148 - 1156. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. N. Sternberg Expanding the boundaries of clinical practice: building on experience with targeted therapies Ann. Onc., May 1, 2009; 20(suppl_1): i1 - i6. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-Y. Blay New paradigms in gastrointestinal stromal tumour management Ann. Onc., May 1, 2009; 20(suppl_1): i18 - i24. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. W. Pratz, J. Cortes, G. J. Roboz, N. Rao, O. Arowojolu, A. Stine, Y. Shiotsu, A. Shudo, S. Akinaga, D. Small, et al. A pharmacodynamic study of the FLT3 inhibitor KW-2449 yields insight into the basis for clinical response Blood, April 23, 2009; 113(17): 3938 - 3946. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Gandhi, K. L. McNamara, D. Li, C. L. Borgman, U. McDermott, K. A. Brandstetter, R. F. Padera, L. R. Chirieac, J. E. Settleman, and K.-K. Wong Sunitinib Prolongs Survival in Genetically Engineered Mouse Models of Multistep Lung Carcinogenesis Cancer Prevention Research, April 1, 2009; 2(4): 330 - 337. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. E. Houk, C. L. Bello, D. Kang, and M. Amantea A Population Pharmacokinetic Meta-analysis of Sunitinib Malate (SU11248) and Its Primary Metabolite (SU12662) in Healthy Volunteers and Oncology Patients Clin. Cancer Res., April 1, 2009; 15(7): 2497 - 2506. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Stacchiotti, E. Tamborini, A. Marrari, S. Brich, S. A. Rota, M. Orsenigo, F. Crippa, C. Morosi, A. Gronchi, M. A. Pierotti, et al. Response to Sunitinib Malate in Advanced Alveolar Soft Part Sarcoma Clin. Cancer Res., February 1, 2009; 15(3): 1096 - 1104. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Q. Zhou and J. M. Gallo Differential effect of sunitinib on the distribution of temozolomide in an orthotopic glioma model Neuro-oncol, January 1, 2009; 11(3): 301 - 310. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Card, C. Caldwell, H. Min, B. Lokchander, Hualin Xi, S. Sciabola, A. V. Kamath, S. L. Clugston, W. R. Tschantz, Leyu Wang, et al. High-Throughput Biochemical Kinase Selectivity Assays: Panel Development and Screening Applications J Biomol Screen, January 1, 2009; 14(1): 31 - 42. [Abstract] [PDF]
|
|
|
|
 |
|
 S. Patyna, C. Arrigoni, A. Terron, T.-W. Kim, J. K. Heward, S. L. Vonderfecht, R. Denlinger, S. E. Turnquist, and W. Evering Nonclinical Safety Evaluation of Sunitinib: A Potent Inhibitor of VEGF, PDGF, KIT, FLT3, and RET Receptors Toxicol Pathol, December 1, 2008; 36(7): 905 - 916. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. C. Heinrich, R. G. Maki, C. L. Corless, C. R. Antonescu, A. Harlow, D. Griffith, A. Town, A. Mckinley, W.-B. Ou, J. A. Fletcher, et al. Primary and Secondary Kinase Genotypes Correlate With the Biological and Clinical Activity of Sunitinib in Imatinib-Resistant Gastrointestinal Stromal Tumor J. Clin. Oncol., November 20, 2008; 26(33): 5352 - 5359. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. van Cruijsen, A. A.M. van der Veldt, L. Vroling, D. Oosterhoff, H. J. Broxterman, R. J. Scheper, G. Giaccone, J. B.A.G. Haanen, A. J.M. van den Eertwegh, E. Boven, et al. Sunitinib-Induced Myeloid Lineage Redistribution in Renal Cell Cancer Patients: CD1c+ Dendritic Cell Frequency Predicts Progression-Free Survival Clin. Cancer Res., September 15, 2008; 14(18): 5884 - 5892. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. H. Kulke, H.-J. Lenz, N. J. Meropol, J. Posey, D. P. Ryan, J. Picus, E. Bergsland, K. Stuart, L. Tye, X. Huang, et al. Activity of Sunitinib in Patients With Advanced Neuroendocrine Tumors J. Clin. Oncol., July 10, 2008; 26(20): 3403 - 3410. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Letard, Y. Yang, K. Hanssens, F. Palmerini, P. S. Leventhal, S. Guery, A. Moussy, J.-P. Kinet, O. Hermine, and P. Dubreuil Gain-of-Function Mutations in the Extracellular Domain of KIT Are Common in Canine Mast Cell Tumors Mol. Cancer Res., July 1, 2008; 6(7): 1137 - 1145. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q. Zhou, P. Guo, and J. M. Gallo Impact of Angiogenesis Inhibition by Sunitinib on Tumor Distribution of Temozolomide Clin. Cancer Res., March 1, 2008; 14(5): 1540 - 1549. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Socinski, S. Novello, J. R. Brahmer, R. Rosell, J. M. Sanchez, C. P. Belani, R. Govindan, J. N. Atkins, H. H. Gillenwater, C. Pallares, et al. Multicenter, Phase II Trial of Sunitinib in Previously Treated, Advanced Non-Small-Cell Lung Cancer J. Clin. Oncol., February 1, 2008; 26(4): 650 - 656. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Rambaldi, T. Barbui, and G. Barosi From Palliation to Epigenetic Therapy in Myelofibrosis Hematology, January 1, 2008; 2008(1): 83 - 91. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. M. Stone Genetically Defined Prognostic Factors and Novel Therapeutics for AML ASCO Educational Book, January 1, 2008; 2008(1): 280 - 284. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Widakowich, G. de Castro Jr., E. de Azambuja, P. Dinh, and A. Awada Review: Side Effects of Approved Molecular Targeted Therapies in Solid Cancers Oncologist, December 1, 2007; 12(12): 1443 - 1455. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. B. Saltz, L. S. Rosen, J. L. Marshall, R. J. Belt, H. I. Hurwitz, S. G. Eckhardt, E. K. Bergsland, D. G. Haller, A. C. Lockhart, C. M. Rocha Lima, et al. Phase II Trial of Sunitinib in Patients With Metastatic Colorectal Cancer After Failure of Standard Therapy J. Clin. Oncol., October 20, 2007; 25(30): 4793 - 4799. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Martin and R. Schilder Novel Approaches in Advancing the Treatment of Epithelial Ovarian Cancer: The Role of Angiogenesis Inhibition J. Clin. Oncol., July 10, 2007; 25(20): 2894 - 2901. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. B. Shankar, J. Li, P. Tapang, J. Owen McCall, L. J. Pease, Y. Dai, R.-Q. Wei, D. H. Albert, J. J. Bouska, D. J. Osterling, et al. ABT-869, a multitargeted receptor tyrosine kinase inhibitor: inhibition of FLT3 phosphorylation and signaling in acute myeloid leukemia Blood, April 15, 2007; 109(8): 3400 - 3408. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Giaccone The Potential of Antiangiogenic Therapy in Non-Small Cell Lung Cancer Clin. Cancer Res., April 1, 2007; 13(7): 1961 - 1970. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Q.M. Chow and S. G. Eckhardt Sunitinib: From Rational Design to Clinical Efficacy J. Clin. Oncol., March 1, 2007; 25(7): 884 - 896. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q. Yao, B. Weigel, and J. Kersey Synergism between Etoposide and 17-AAG in Leukemia Cells: Critical Roles for Hsp90, FLT3, Topoisomerase II, Chk1, and Rad51 Clin. Cancer Res., March 1, 2007; 13(5): 1591 - 1600. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. I. Rini Vascular Endothelial Growth Factor-Targeted Therapy in Renal Cell Carcinoma: Current Status and Future Directions Clin. Cancer Res., February 15, 2007; 13(4): 1098 - 1106. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
O. Piloto, M. Wright, P. Brown, K.-T. Kim, M. Levis, and D. Small Prolonged exposure to FLT3 inhibitors leads to resistance via activation of parallel signaling pathways Blood, February 15, 2007; 109(4): 1643 - 1652. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Gridelli, P. Maione, F. Del Gaizo, G. Colantuoni, C. Guerriero, C. Ferrara, D. Nicolella, D. Comunale, A. De Vita, and A. Rossi Sorafenib and Sunitinib in the Treatment of Advanced Non-Small Cell Lung Cancer Oncologist, February 1, 2007; 12(2): 191 - 200. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. J. Motzer, T. E. Hutson, P. Tomczak, M. D. Michaelson, R. M. Bukowski, O. Rixe, S. Oudard, S. Negrier, C. Szczylik, S. T. Kim, et al. Sunitinib versus Interferon Alfa in Metastatic Renal-Cell Carcinoma N. Engl. J. Med., January 11, 2007; 356(2): 115 - 124. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Knapper, A. K. Burnett, T. Littlewood, W. J. Kell, S. Agrawal, R. Chopra, R. Clark, M. J. Levis, and D. Small A phase 2 trial of the FLT3 inhibitor lestaurtinib (CEP701) as first-line treatment for older patients with acute myeloid leukemia not considered fit for intensive chemotherapy Blood, November 15, 2006; 108(10): 3262 - 3270. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. W. Kim, Y. S. Jo, H. S. Jung, H. K. Chung, J. H. Song, K. C. Park, S. H. Park, J. H. Hwang, S. Y. Rha, G. R. Kweon, et al. An Orally Administered Multitarget Tyrosine Kinase Inhibitor, SU11248, Is a Novel Potent Inhibitor of Thyroid Oncogenic RET/Papillary Thyroid Cancer Kinases J. Clin. Endocrinol. Metab., October 1, 2006; 91(10): 4070 - 4076. [Abstract] [Full Text] [PDF]
|
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T. Ikezoe, C. Nishioka, T. Tasaka, Y. Yang, N. Komatsu, K. Togitani, H. P. Koeffler, and H. Taguchi The antitumor effects of sunitinib (formerly SU11248) against a variety of human hematologic malignancies: enhancement of growth inhibition via inhibition of mammalian target of rapamycin signaling. Mol. Cancer Ther., October 1, 2006; 5(10): 2522 - 2530. [Abstract] [Full Text] [PDF]
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S. Patyna, A. D. Laird, D. B. Mendel, A.-M. O'Farrell, C. Liang, H. Guan, T. Vojkovsky, S. Vasile, X. Wang, J. Chen, et al. SU14813: a novel multiple receptor tyrosine kinase inhibitor with potent antiangiogenic and antitumor activity. Mol. Cancer Ther., July 1, 2006; 5(7): 1774 - 1782. [Abstract] [Full Text] [PDF]
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A. Morabito, E. De Maio, M. Di Maio, N. Normanno, and F. Perrone Tyrosine Kinase Inhibitors of Vascular Endothelial Growth Factor Receptors in Clinical Trials: Current Status and Future Directions Oncologist, July 1, 2006; 11(7): 753 - 764. [Abstract] [Full Text] [PDF]
|
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 R. J. Motzer, B. I. Rini, R. M. Bukowski, B. D. Curti, D. J. George, G. R. Hudes, B. G. Redman, K. A. Margolin, J. R. Merchan, G. Wilding, et al. Sunitinib in patients with metastatic renal cell carcinoma. JAMA, June 7, 2006; 295(21): 2516 - 2524. [Abstract] [Full Text] [PDF]
|
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 O. Piloto, B. Nguyen, D. Huso, K.-T. Kim, Y. Li, L. Witte, D. J. Hicklin, P. Brown, and D. Small IMC-EB10, an Anti-FLT3 Monoclonal Antibody, Prolongs Survival and Reduces Nonobese Diabetic/Severe Combined Immunodeficient Engraftment of Some Acute Lymphoblastic Leukemia Cell Lines and Primary Leukemic Samples. Cancer Res., May 1, 2006; 66(9): 4843 - 4851. [Abstract] [Full Text] [PDF]
|
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O. Potapova, A. D. Laird, M. A. Nannini, A. Barone, G. Li, K. G. Moss, J. M. Cherrington, and D. B. Mendel Contribution of individual targets to the antitumor efficacy of the multitargeted receptor tyrosine kinase inhibitor SU11248 Mol. Cancer Ther., May 1, 2006; 5(5): 1280 - 1289. [Abstract] [Full Text] [PDF]
|
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 A. Schirmer, J. Kennedy, S. Murli, R. Reid, and D. V. Santi Targeted covalent inactivation of protein kinases by resorcylic acid lactone polyketides. PNAS, March 14, 2006; 103(11): 4234 - 4239. [Abstract] [Full Text] [PDF]
|
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|
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R. J. Motzer, M. D. Michaelson, B. G. Redman, G. R. Hudes, G. Wilding, R. A. Figlin, M. S. Ginsberg, S. T. Kim, C. M. Baum, S. E. DePrimo, et al. Activity of SU11248, a Multitargeted Inhibitor of Vascular Endothelial Growth Factor Receptor and Platelet-Derived Growth Factor Receptor, in Patients With Metastatic Renal Cell Carcinoma J. Clin. Oncol., January 1, 2006; 24(1): 16 - 24. [Abstract] [Full Text] [PDF]
|
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M. M. Schittenhelm, S. Shiraga, A. Schroeder, A. S. Corbin, D. Griffith, F. Y. Lee, C. Bokemeyer, M. W.N. Deininger, B. J. Druker, and M. C. Heinrich Dasatinib (BMS-354825), a Dual SRC/ABL Kinase Inhibitor, Inhibits the Kinase Activity of Wild-Type, Juxtamembrane, and Activation Loop Mutant KIT Isoforms Associated with Human Malignancies Cancer Res., January 1, 2006; 66(1): 473 - 481. [Abstract] [Full Text] [PDF]
|
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D. Small FLT3 Mutations: Biology and Treatment Hematology, January 1, 2006; 2006(1): 178 - 184. [Abstract] [Full Text] [PDF]
|
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R. E. Gale, R. Hills, A. R. Pizzey, P. D. Kottaridis, D. Swirsky, A. F. Gilkes, E. Nugent, K. I. Mills, K. Wheatley, E. Solomon, et al. Relationship between FLT3 mutation status, biologic characteristics, and response to targeted therapy in acute promyelocytic leukemia Blood, December 1, 2005; 106(12): 3768 - 3776. [Abstract] [Full Text] [PDF]
|
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 R. Tussiwand, N. Onai, L. Mazzucchelli, and M. G. Manz Inhibition of Natural Type I IFN-Producing and Dendritic Cell Development by a Small Molecule Receptor Tyrosine Kinase Inhibitor with Flt3 Affinity J. Immunol., September 15, 2005; 175(6): 3674 - 3680. [Abstract] [Full Text] [PDF]
|
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P. Marzola, A. Degrassi, L. Calderan, P. Farace, E. Nicolato, C. Crescimanno, M. Sandri, A. Giusti, E. Pesenti, A. Terron, et al. Early Antiangiogenic Activity of SU11248 Evaluated In vivo by Dynamic Contrast-Enhanced Magnetic Resonance Imaging in an Experimental Model of Colon Carcinoma Clin. Cancer Res., August 15, 2005; 11(16): 5827 - 5832. [Abstract] [Full Text] [PDF]
|
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T. A. Carter, L. M. Wodicka, N. P. Shah, A. M. Velasco, M. A. Fabian, D. K. Treiber, Z. V. Milanov, C. E. Atteridge, W. H. Biggs III, P. T. Edeen, et al. Inhibition of drug-resistant mutants of ABL, KIT, and EGF receptor kinases PNAS, August 2, 2005; 102(31): 11011 - 11016. [Abstract] [Full Text] [PDF]
|
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D. E. Lopes de Menezes, J. Peng, E. N. Garrett, S. G. Louie, S. H. Lee, M. Wiesmann, Y. Tang, L. Shephard, C. Goldbeck, Y. Oei, et al. CHIR-258: A Potent Inhibitor of FLT3 Kinase in Experimental Tumor Xenograft Models of Human Acute Myelogenous Leukemia Clin. Cancer Res., July 15, 2005; 11(14): 5281 - 5291. [Abstract] [Full Text] [PDF]
|
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C. Choudhary, J. Schwable, C. Brandts, L. Tickenbrock, B. Sargin, T. Kindler, T. Fischer, W. E. Berdel, C. Muller-Tidow, and H. Serve AML-associated Flt3 kinase domain mutations show signal transduction differences compared with Flt3 ITD mutations Blood, July 1, 2005; 106(1): 265 - 273. [Abstract] [Full Text] [PDF]
|
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|
 D.-E. Schmidt-Arras, A. Bohmer, B. Markova, C. Choudhary, H. Serve, and F.-D. Bohmer Tyrosine Phosphorylation Regulates Maturation of Receptor Tyrosine Kinases Mol. Cell. Biol., May 1, 2005; 25(9): 3690 - 3703. [Abstract] [Full Text] [PDF]
|
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 X.-F. Zhu, B.-F. Xie, J.-M. Zhou, G.-K. Feng, Z.-C. Liu, X.-Y. Wei, F.-X. Zhang, M.-F. Liu, and Y.-X. Zeng Blockade of Vascular Endothelial Growth Factor Receptor Signal Pathway and Antitumor Activity of ON-III (2',4'-Dihydroxy-6'-methoxy-3',5'-dimethylchalcone), a Component from Chinese Herbal Medicine Mol. Pharmacol., May 1, 2005; 67(5): 1444 - 1450. [Abstract] [Full Text] [PDF]
|
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 J. M. Cherrington Taking Biological Targeted Agents into Clinical Trial Am. Assoc. Cancer Res. Educ. Book, April 1, 2005; 2005(1): 23 - 29. [Full Text] [PDF]
|
|
|
|
|
|
J. Schwable, C. Choudhary, C. Thiede, L. Tickenbrock, B. Sargin, C. Steur, M. Rehage, A. Rudat, C. Brandts, W. E. Berdel, et al. RGS2 is an important target gene of Flt3-ITD mutations in AML and functions in myeloid differentiation and leukemic transformation Blood, March 1, 2005; 105(5): 2107 - 2114. [Abstract] [Full Text] [PDF]
|
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G. Gasparini, R. Longo, M. Fanelli, and B. A. Teicher Combination of Antiangiogenic Therapy With Other Anticancer Therapies: Results, Challenges, and Open Questions J. Clin. Oncol., February 20, 2005; 23(6): 1295 - 1311. [Abstract] [Full Text] [PDF]
|
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|
|
|
|
O. Piloto, M. Levis, D. Huso, Y. Li, H. Li, M.-N. Wang, R. Bassi, P. Balderes, D. L. Ludwig, L. Witte, et al. Inhibitory Anti-FLT3 Antibodies Are Capable of Mediating Antibody-Dependent Cell-Mediated Cytotoxicity and Reducing Engraftment of Acute Myelogenous Leukemia Blasts in Nonobese Diabetic/Severe Combined Immunodeficient Mice Cancer Res., February 15, 2005; 65(4): 1514 - 1522. [Abstract] [Full Text] [PDF]
|
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|
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K. Podar and K. C. Anderson The pathophysiologic role of VEGF in hematologic malignancies: therapeutic implications Blood, February 15, 2005; 105(4): 1383 - 1395. [Abstract] [Full Text] [PDF]
|
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|
|
W. Fiedler, H. Serve, H. Dohner, M. Schwittay, O. G. Ottmann, A.-M. O'Farrell, C. L. Bello, R. Allred, W. C. Manning, J. M. Cherrington, et al. A phase 1 study of SU11248 in the treatment of patients with refractory or resistant acute myeloid leukemia (AML) or not amenable to conventional therapy for the disease Blood, February 1, 2005; 105(3): 986 - 993. [Abstract] [Full Text] [PDF]
|
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P. Brown, M. Levis, S. Shurtleff, D. Campana, J. Downing, and D. Small FLT3 inhibition selectively kills childhood acute lymphoblastic leukemia cells with high levels of FLT3 expression Blood, January 15, 2005; 105(2): 812 - 820. [Abstract] [Full Text] [PDF]
|
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M. Wadleigh, D. J. DeAngelo, J. D. Griffin, and R. M. Stone After chronic myelogenous leukemia: tyrosine kinase inhibitors in other hematologic malignancies Blood, January 1, 2005; 105(1): 22 - 30. [Abstract] [Full Text] [PDF]
|
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K. Y. Chung, G. Morrone, J. J. Schuringa, B. Wong, D. C. Dorn, and M. A. S. Moore Enforced expression of an Flt3 internal tandem duplication in human CD34+ cells confers properties of self-renewal and enhanced erythropoiesis Blood, January 1, 2005; 105(1): 77 - 84. [Abstract] [Full Text] [PDF]
|
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K. W. H. Yee, M. Schittenhelm, A.-M. O'Farrell, A. R. Town, L. McGreevey, T. Bainbridge, J. M. Cherrington, and M. C. Heinrich Synergistic effect of SU11248 with cytarabine or daunorubicin on FLT3 ITD-positive leukemic cells Blood, December 15, 2004; 104(13): 4202 - 4209. [Abstract] [Full Text] [PDF]
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J. J. Clark, J. Cools, D. P. Curley, J.-C. Yu, N. A. Lokker, N. A. Giese, and D. G. Gilliland Variable sensitivity of FLT3 activation loop mutations to the small molecule tyrosine kinase inhibitor MLN518 Blood, November 1, 2004; 104(9): 2867 - 2872. [Abstract] [Full Text] [PDF]
|
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P. Brown, S. Meshinchi, M. Levis, T. A. Alonzo, R. Gerbing, B. Lange, R. Arceci, and D. Small Pediatric AML primary samples with FLT3/ITD mutations are preferentially killed by FLT3 inhibition Blood, September 15, 2004; 104(6): 1841 - 1849. [Abstract] [Full Text] [PDF]
|
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|
|
|
|
Y. Li, H. Li, M.-N. Wang, D. Lu, R. Bassi, Y. Wu, H. Zhang, P. Balderes, D. L. Ludwig, B. Pytowski, et al. Suppression of leukemia expressing wild-type or ITD-mutant FLT3 receptor by a fully human anti-FLT3 neutralizing antibody Blood, August 15, 2004; 104(4): 1137 - 1144. [Abstract] [Full Text] [PDF]
|
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M. Levis, R. Pham, B. D. Smith, and D. Small In vitro studies of a FLT3 inhibitor combined with chemotherapy: sequence of administration is important to achieve synergistic cytotoxic effects Blood, August 15, 2004; 104(4): 1145 - 1150. [Abstract] [Full Text] [PDF]
|
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J. A. Cain, J. L. Grisolano, A. D. Laird, and M. H. Tomasson Complete remission of TEL-PDGFRB-induced myeloproliferative disease in mice by receptor tyrosine kinase inhibitor SU11657 Blood, July 15, 2004; 104(2): 561 - 564. [Abstract] [Full Text] [PDF]
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B. D. Smith, M. Levis, M. Beran, F. Giles, H. Kantarjian, K. Berg, K. M. Murphy, T. Dauses, J. Allebach, and D. Small Single-agent CEP-701, a novel FLT3 inhibitor, shows biologic and clinical activity in patients with relapsed or refractory acute myeloid leukemia Blood, May 15, 2004; 103(10): 3669 - 3676. [Abstract] [Full Text] [PDF]
|
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M. G. Mohi, C. Boulton, T.-L. Gu, D. W. Sternberg, D. Neuberg, J. D. Griffin, D. G. Gilliland, and B. G. Neel Combination of rapamycin and protein tyrosine kinase (PTK) inhibitors for the treatment of leukemias caused by oncogenic PTKs PNAS, March 2, 2004; 101(9): 3130 - 3135. [Abstract] [Full Text] [PDF]
|
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A.-M. O'Farrell, J. M. Foran, W. Fiedler, H. Serve, R. L. Paquette, M. A. Cooper, H. A. Yuen, S. G. Louie, H. Kim, S. Nicholas, et al. An Innovative Phase I Clinical Study Demonstrates Inhibition of FLT3 Phosphorylation by SU11248 in Acute Myeloid Leukemia Patients Clin. Cancer Res., November 15, 2003; 9(15): 5465 - 5476. [Abstract] [Full Text] [PDF]
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 K. G. Moss, G. C. Toner, J. M. Cherrington, D. B. Mendel, and A. D. Laird Hair Depigmentation Is a Biological Readout for Pharmacological Inhibition of KIT in Mice and Humans J. Pharmacol. Exp. Ther., November 1, 2003; 307(2): 476 - 480. [Abstract] [Full Text] [PDF]
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T. J. Abrams, L. J. Murray, E. Pesenti, V. Walker Holway, T. Colombo, L. B. Lee, J. M. Cherrington, and N. K. Pryer Preclinical evaluation of the tyrosine kinase inhibitor SU11248 as a single agent and in combination with "standard of care" therapeutic agents for the treatment of breast cancer Mol. Cancer Ther., October 1, 2003; 2(10): 1011 - 1021. [Abstract] [Full Text]
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J. H. Antin A 41-Year-Old Woman With Chronic Myelogenous Leukemia JAMA, August 27, 2003; 290(8): 1083 - 1090. [Full Text] [PDF]
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B. Lowenberg, J. D. Griffin, and M. S. Tallman Acute Myeloid Leukemia and Acute Promyelocytic Leukemia Hematology, January 1, 2003; 2003(1): 82 - 101. [Abstract] [Full Text] [PDF]
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Top
Abstract
Introduction
) was administered to mice bearing large tumors (2000 mm3) from the original vehicle-treated control group (
).
(B) In mice with fully regressed tumors, dosing of SU11248 at 40 mg/kg/d was ceased and tumor regrowth occurred in some animals. When
tumor volume exceeded 1000 mm3, SU11248 administration at
40 mg/kg/d recommenced to evaluate any alteration in sensitivity to the
compound (4 mice). Tumor volume was measured on the indicated days,
with the mean tumor volume ± SEM indicated for each group, each
of which consisted of 10 mice (excluding panel B). (D) Athymic mice
bearing established MV4;11 tumor xenografts were given a single oral
dose of SU11248 (40 mg/kg) or citrate buffer vehicle; predose animals
received no treatment. FLT3 (top panel) or Stat5 (bottom panel) were
immunoprecipitated from tumor lysates, and Western blots were probed
for phosphotyrosine or phospho-Stat5, respectively. Blots were reprobed
for total FLT3 or Stat5. Each lane represents a separate animal. Lane
labeled "ctrl" is positive control cell lysate for FLT3
immunoprecipitation.
