Multi-Targeted Receptor Tyrosine Kinase Inhibitor, ABT-869, Induces Apoptosis and Suppresses Proliferation of Ba/F3 FLT-3 ITD Mutant Cells in Vitro and in Vivo through Inhibition of FLT3 and AKT.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1938-1938
Author(s):  
Jenny E Hernandez ◽  
Joan Zape ◽  
Keith Glaser ◽  
Elliot Landaw ◽  
Cecilia Fu ◽  
...  

Abstract FLT3 is a receptor tyrosine kinase of the subclass III family that plays a vital role in the regulation of differentiation, proliferation and survival of normal hematopoietic cells. FLT3 mutations are often found in patients with acute myelogenous leukemia (AML) and confer a poor prognosis. Of these mutations, 15–35% are FLT3 ITD (internal tandem duplication) mutations and 5–7% are point mutations in the FLT3 kinase activation loop, e.g. D835V. We are studying the signaling pathways associated with a small molecule multi-targeted receptor tyrosine kinase inhibitor (RTKI), ABT-869. To determine the effects of ABT-869 in vitro and in vivo, a Ba/F3 mouse pro-B lymphocytic cell line harboring the FLT-3 ITD or FLT-3 D835V mutation was used as an isolated FLT-3 mutant model system. In vitro, ABT-869 is effective in inhibiting the proliferation of Ba/F3 Flt-3 ITD mutant cells (IC50 value of 1 nM) when compared to Ba/F3 Flt-3 D835V mutant (IC50 value between 1 and 10 μM) and Ba/F3 Flt-3 wildtype (WT) cells (IC50 value of 10 μM). Annexin V and propidium iodide staining of cells revealed that an increase in apoptosis occurred in Ba/F3 Flt-3 ITD mutant cells treated with 1μM ABT-869 for 24 hours (42.8%) when compared to untreated (4.7%) or vehicle control (4.0%) cells. Ba/F3 Flt-3 D835V mutant cell lines demonstrated a 12.5% rate of apoptosis at 1μM, compared to untreated (1.99%) and vehicle control (2.1%) cell lines. Propidium iodide staining of treated Ba/F3 Flt-3 WT cell lines revealed no difference in apoptosis when compared to untreated Ba/F3 Flt-3 WT cells or DMSO controls. PARP cleavage was observed in Ba/F3 FLT-3 ITD mutant cells, following 6 hours of treatment with 1 to 100 nM ABT-869, whereas no cleavage was observed in Ba/F3 WT cells treated with ABT-869. To study the effects of ABT-869 in vivo, we treated SCID mice injected with Ba/F3 Flt-3 ITD, Ba/F3 Flt-3 D835V, or Ba/F3 Flt-3 WT cells and monitored disease progression using bioluminescence imaging. The mice injected with the Ba/F3 FLT-3 ITD mutant cells and treated with vehicle control developed metastases and had a median survival time of 2 weeks. In contrast, the ABT-869 treated group had slower disease progression with median survival of 6.2 weeks (P<0.008). Both control and treated mice injected with Ba/F3 FLT-3 D835V mutant cell lines developed metastases and had similar survival (median 1.7 and 1.9 weeks, respectively). Survival times of control and treated mice injected with Ba/F3 FLT-3 WT cells were also similar (median 8.4 and 8.1 weeks, respectively). Previous work identified that ABT-869 induced apoptosis of acute myeloid leukemia cells through inhibition of FLT-3 reception phosphorylation, which is observed as early as 3 hours after treatment. In Ba/F3 cells expressing FLT-3 ITD, ABT-869 also inhibited phosphorylation of AKT, which is upstream of the pro-apoptotic protein Bad. Therefore, our preclinical data suggest that ABT-869 induces apoptosis of FLT-3 ITD mutant cells both in vitro and in vivo. These studies provide rationale for the treatment of acute leukemia patients harboring the FLT3-ITD mutation with ABT-869 and the potential benefit of combining small molecule inhibitors that target both RTKs and AKT.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1589-1589
Author(s):  
Jenny E. Hernandez ◽  
Junling Li ◽  
Ru-Qi Wei ◽  
Paul Tapang ◽  
Steven K. Davidsen ◽  
...  

Abstract FLT3 is an receptor tyrosine kinase of the subclass III family that plays a vital role in the regulation of the differentiation, proliferation and survival of normal hematopoietic cells. FLT3 mutations are often found in patients with Acute myelogenous leukemia (AML) and confer poor prognosis. Of these mutations, 15–35% are FLT3 ITD (internal tandem duplication) mutations and 5–7% are point mutations on the FLT3 kinase activation loop (e.g. D835V). Our laboratory is studying the signaling pathways associated with a newly identified multi-targeted tyrosine kinase receptor small molecule inhibitor (RTKI), ABT-869. Recently published work in our laboratory showed that using ABT-869 to treat MV4-11, a human AML FLT-3 ITD mutant cell line, resulted in the inhibition of phosphorylation of FLT-3 with a downstream inhibitory effect on the activation of STAT5, ERK, and Pim-1. Cell viability assays determined that MV-411 cells responded to ABT-869 in a concentration dependent manner (IC50 = 10nM). Apoptosis studies also showed an induction of apoptosis in ABT-869 treated cells. In vivo studies involving xenograft injections of MV-411 cells into SCID mice and subsequent treatment with ABT-869 demonstrated regression of tumor formation. In this study, a Ba/F3 mouse pro-B lymphocytic cell line harboring the FLT-3 ITD or FLT-3 D835V mutation is used as an isolated Flt-3 mutant model system. In vitro, ABT-869 is effective in inhibiting the proliferation of Ba/F3 Flt-3 ITD mutant cells when compared to Ba/F3 Flt-3 D835V mutant and Ba/F3 Flt-3 WT cells. Trypan Blue Exclusion and Alamar Blue assays were used to demonstrate that there is 50% inhibition of growth and proliferation (IC50) of Ba/F3 FLT3 ITD mutant cells at a concentration of 1nM after 48 hours of treatment. Ba/F3 FLT3 D835V mutant cells show an IC50 between 1μM and 10μM after 48 hours of treatment. In contrast, Ba/F3 FLT3 WT cells demonstrate an IC50 of 10μM only after 72 hours of treatment. Annexin V and propidium iodide staining of cells revealed that an increase in apoptosis (41.2%) occurred in Ba/F3 Flt-3 ITD mutant cells treated with 10nM ABT-869 after 24 hours when compared to untreated (6.5%) or vehicle control (6.1%) cells. Staining of Ba/F3 Flt-3 WT treated cell lines revealed no difference in apoptosis when compared to untreated Ba/F3 Flt-3 WT cell only and DMSO controls. PARP cleavage was observed in Ba/F3 FLT-3 ITD mutant cells following treatment with ABT-869 whereas no cleavage was observed with Ba/F3 WT cells treated with ABT-869. In vivo, the activity of ABT-869 treatment of SCID mice injected with Baf3 Flt-3 ITD, Baf3 Flt-3 D835V, or Baf3 Flt-3 WT cells is also being evaluated. Using bioluminescence imaging, it was determined that Ba/F3 FLT-3 ITD mutant and Ba/F3 Flt-3 D835Vmutant cell lines result in metastases and subsequent death in SCID mice after 2 weeks for ITD and 5 weeks for D835V, whereas mice injected with Ba/F3 WT survive longer than 5 weeks. Preliminary data demonstrated that ABT-869 prolonged survival in mice injected with the Ba/F3 FLT3-ITD cells compared to controls. Our preclinical data demonstrate that ABT-869 is effective specifically with FLT-3 ITD mutant cell lines in an isolated system. These studies provide rationale for the treatment of AML patients and the prevention of relapse.


2002 ◽  
Vol 50 (6) ◽  
pp. 479-489 ◽  
Author(s):  
Ioannis A. Avramis ◽  
Garyfallia Christodoulopoulos ◽  
Atsushi Suzuki ◽  
Walter E. Laug ◽  
Ignacio Gonzalez-Gomez ◽  
...  

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 641-641 ◽  
Author(s):  
Suzanne Trudel ◽  
Zhi Hua Li ◽  
Ellen Wei ◽  
Marion Wiesmann ◽  
Katherine Rendahl ◽  
...  

Abstract The t(4;14) translocation that occurs uniquely in a subset (15%) of multiple myeloma (MM) patients results in the ectopic expression of the receptor tyrosine kinase, Fibroblast Growth Factor Receptor3 (FGFR3). Wild-type FGFR3 induces proliferative signals in myeloma cells and appears to be weakly transforming in a hematopoeitic mouse model. The subsequent acquisition of FGFR3 activating mutations in some MM is associated with disease progression and is strongly transforming in several experimental models. The clinical impact of t(4;14) translocations has been demonstrated in several retrospective studies each reporting a marked reduction in overall survival. We have previously shown that inhibition of activated FGFR3 causes morphologic differentiation followed by apoptosis of FGFR3 expressing MM cell lines, validating activated FGFR3 as a therapeutic target in t(4;14) MM and encouraging the clinical development of FGFR3 inhibitors for the treatment of these poor-prognosis patients. CHIR258 is a small molecule kinase inhibitor that targets Class III–V RTKs and inhibits FGFR3 with an IC50 of 5 nM in an in vitro kinase assay. Potent anti-tumor and anti-angiogenic activity has been demonstrated in vitro and in vivo. We employed the IL-6 dependent cell line, B9 that has been engineered to express wild-type FGFR3 or active mutants of FGFR3 (Y373C, K650E, G384D and 807C), to screen CHIR258 for activity against FGFR3. CHIR258 differentially inhibited FGF-mediated growth of B9 expressing wild-type and mutant receptors found in MM, with an IC50 of 25 nM and 80 nM respectively as determined by MTT proliferation assay. Growth of these cells could be rescued by IL-6 demonstrating selectivity of CHIR258 for FGFR3. We then confirmed the activity of CHIR258 against FGFR3 expressing myeloma cells. CHIR258 inhibited the viability of FGFR3 expressing KMS11 (Y373C), KMS18 (G384D) and OPM-2 (K650E) cell lines with an IC50 of 100 nM, 250 nM and 80 nM, respectively. Importantly, inhibition with CHIR258 was still observed in the presence of IL-6, a potent growth factors for MM cells. U266 cells, which lack FGFR3 expression, displayed minimal growth inhibition demonstrating that at effective concentrations, CHIR258 exhibits minimal nonspecific cytotoxicity on MM cells. Further characterization of this finding demonstrated that inhibition of cell growth corresponded to G0/G1 cell cycle arrest and dose-dependent inhibition of downstream ERK phosphorylation. In responsive cell lines, CHIR258 induced apoptosis via caspase 3. In vitro combination analysis of CHIR258 and dexamethasone applied simultaneously to KMS11 cells indicated a synergistic interaction. In vivo studies demonstrated that CHIR258 induced tumor regression and inhibited growth of FGFR3 tumors in a plasmacytoma xenograft mouse model. Finally, CHIR258 produced cytotoxic responses in 4/5 primary myeloma samples derived from patients harboring a t(4;14) translocation. These data indicate that the small molecule inhibitor, CHIR258 potently inhibits FGFR3 and has activity against human MM cells setting the stage for a Phase I clinical trial of this compound in t(4;14) myeloma.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 616-616 ◽  
Author(s):  
Deepa B. Shankar ◽  
Jenny C. Chang ◽  
Bertrand Parcells ◽  
Salemiz Sandoval ◽  
Junling Li ◽  
...  

Abstract Children with acute myeloid leukemia (AML) have less than 60% overall survival despite aggressive chemotherapy and bone marrow transplantation. Only one third of the adult patients diagnosed with AML will be cured. AML blast cells from up to 30% of patients express a constitutively active receptor tyrosine kinase, FLT3-ITD, which contains an internal tandem duplication in the juxtamembrane domain. Patients with FLT3-ITD have a worse prognosis. ABT-869 is a novel multi-targeted small molecule inhibitor of receptor tyrosine kinases and is a potent inhibitor of FLT3, c-Kit, and all members of the VEGF and PDGF receptor families. To determine the effects of ABT-896 on AML cells, we treated AML cell lines, primary cells, and tumors in xenograft models with varying concentrations of the drug. In vitro viability assays showed that ABT-869 inhibited the growth of two different cell lines, MV-4-11 (human AML cell line that expresses FLT3-ITD) and BAF3-ITD (murine B-cell line stably transfected with the FLT3-ITD) at an IC50 of 10nM. ABT-869 was also effective against another mutation of FLT3, D835V, but at higher concentrations (IC50 of 100nM). Phosphorylation of FLT3 and activation of downstream signaling molecules, STAT5 and ERK, were inhibited by ABT-869 in a concentration-dependent manner. Cells were also stained with Annexin V-FITC and Propidium Iodide, and analyzed using FACS. ABT-869 induced apoptosis, caspase-3 activation, and PARP cleavage after 48 hours. To examine the in vitro effects of ABT-869 on normal hematopoietic progenitor cells, we performed methylcellulose-based colony assays with human bone marrow. No significant difference was observed in the number and type of colonies formed using BM cells treated with ABT-869 or control, up to a concentration of 1 micromolar. These results suggest that ABT-869 is not toxic to normal bone marrow progenitor cells at concentrations that are effective against AML cells. To examine the effects of ABT-869 in vivo, we treated SCID mice injected with MV-4-11, Baf3-ITD, Baf3-D835V, or Baf3-WT cells, with oral preparations of ABT-869. Complete regression of MV-4-11 tumors was observed in mice treated with ABT-869 at 20 and 40 mg/kg/day. No adverse effects were detected in the peripheral blood counts, bone marrow, spleen or liver. Histology of the tumors from the control-treated group showed a high degree of proliferation by Ki-67 staining, increased mitotic figures, and a well-defined tumor mass. In contrast, the tumors from mice treated with ABT-869 showed a number of apoptotic bodies by TUNEL staining and the presence of reactive, inflammatory cells. Interestingly, we also observed that mice that received ABT-869 the day after injection of AML cells remained tumor-free for over 2 months in contrast to the mice receiving the vehicle alone. Inhibition of FLT3 phosphorylation was demonstrated in the tumors from mice treated with ABT-869. We are evaluating the activity of ABT-869 treatment of SCID mice injected with Baf3-ITD, Baf3-D835V, or Baf3-WT cells. NOD-SCID mouse models are currently being used to analyze the effects of ABT-869 on primary AML cells in vivo. Our preclinical studies demonstrate that ABT-869 is effective and nontoxic, and provide rationale for the treatment and prevention of relapse in AML patients.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 11044-11044
Author(s):  
Lillian Rose Klug ◽  
Jeffrey Tyner ◽  
Michael C. Heinrich

11044 Background: Multiple cancers, such as gastrointestinal stromal tumors (GIST) and melanoma, have been shown to be caused by somatic activating mutations in the receptor tyrosine kinase KIT. The major cause of death in patients with advanced KIT -mutant cancers is due to the development of KIT tyrosine kinase inhibitor-resistant (TKI-resistant) metastatic disease. Drug resistance arises almost exclusively from secondary mutations within KIT, highlighting the importance of KIT in the proliferation and survival of these tumors. Methods: We performed a human kinase siRNA screen in multiple KIT -mutant cancer cell lines using viability as a read out. We defined candidate targets as those whose knockdown decreased viability in all cell lines. Validation and mechanistic studies were done using a library of KIT-mutant GIST and melanoma cells. Results: We identified lemur tyrosine kinase 3 (LMTK3) as candidate target in three KIT -mutant cell lines. LMTK3 silencing reduced the viability of all KIT -mutant GIST and melanoma cells tested to date, including cell lines with KIT TKI-resistance mutations. Importantly, LMTK3 silencing decreased the viability of KIT -mutant cells specifically, but not that of KIT-independent GIST and melanoma cells. Further, we found that decreased cell viability was due to induction of apoptosis, as assessed by measuring caspase 3 and 7 activity within 96 hours of LMTK3 silencing. LMTK3 knockdown also reduced tumor growth in vivo in a GIST xenograft model. Because these cells depend so heavily on KIT and the loss of KIT signaling results in cell death, we hypothesized that LMTK3 silencing may affect this pathway. Indeed, LMTK3 silencing decreased levels of autophosphorylated KIT. We also observed a significant decrease in total KIT protein expression. This phenotype and corresponding viability was rescued with exogenous expression of full length LMTK3. Conclusions: LMTK3 is an important regulator of oncogenic KIT expression and activity in KIT-mutant GIST and melanoma and represents a novel, tractable target.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 640-640
Author(s):  
Karin Vanderkerken ◽  
Eline Menu ◽  
Thomas Stromberg ◽  
Hendrik De Raeve ◽  
Kewal Asosingh ◽  
...  

Abstract Multiple myeloma (MM) represents a B-cell malignancy, characterized by monoclonal proliferation of plasma cells in the bone marrow (BM) and is associated with osteolysis and angiogenesis. Insulin-like growth factor-1 (IGF-1), produced by the BM stromal cells, has been described as an important factor in the survival, proliferation and migration of MM cells. The latter process is involved in the homing of the MM cells to the BM. IGF-1 also induces VEGF secretion by the MM cells, thus stimulating angiogenesis in the BM. As IGF-1 is a pleiotropic factor in MM, therapeutic strategies targeting the IGF-1R may be effective as anti-tumor treatments. In this work we investigated the effect of an IGF-1 receptor tyrosine kinase inhibitor (picropodophyllin or PPP1) in the murine, syngeneic 5T33MM model of multiple myeloma. This mouse model is representative for the human disease and can combine in vitro and in vivo studies. We first investigated the effects of PPP on the MM cells in vitro. We and others have previously demonstrated that IGF-1 induced ERK activation, involved in VEGF secretion and proliferation. When the 5T33MM cells were preincubated with 1microM PPP, Western blot analysis demonstrated the blocking of this activation. Furthermore, when the 5T33MM cells were preincubated with PPP for 30 min, IGF-1 induced VEGF secretion and proliferation of the 5T33MM cells were completely blocked. Next, we used the tyrosine kinase inhibitor PPP in vivo. 5T33MM cells were injected intravenously in C57BLKaLwRij mice and the development of the disease was monitored by measuring the serum paraprotein concentration. Mice were either treated with a low (17mM, IP, twice a day) or a high dose of PPP (50mM, IP, twice a day) or with the vehicle (DMSO/oil 9/1) from the day of injection with 5T33MM onward. At week 3, vehicle controls showed signs of morbidity and were sacrificed. The presence of tumor was measured by assessing serum paraprotein concentrations and determining the proportion of idiotype positive cells in the BM by flow cytometry. Angiogenesis was assessed by measuring the microvessel density on CD31 stained paraffin sections. The tumor burden in the bone marrow in the PPP treated mice was 77% lower than in vehicle treated animals (p< 0,0001) and the serum paraprotein concentration was 90% lower (p< 0,0001). The microvessel density in the BM of the PPP treated group was reduced by 60% (p< 0,02). In a separate survival experiment the mice were either treated with the vehicle or with the high dose (50mM) of PPP, from the time of tumor injection. Kaplan-Meier analysis demonstrated a significant increase in survival after treatment with PPP when compared with vehicle (28 vs. 18 days, p<0,001). These data demonstrate that the IGF-1RTK inhibitor PPP possesses strong anti-tumor activity, as demonstrated both in vitro and in vivo in a syngeneic model of multiple myeloma, and may therefore be an effective therapeutic candidate for MM treatment.


Blood ◽  
2014 ◽  
Vol 123 (10) ◽  
pp. 1525-1534 ◽  
Author(s):  
Hayley Ma ◽  
Bao Nguyen ◽  
Li Li ◽  
Sarah Greenblatt ◽  
Allen Williams ◽  
...  

Key Points A novel TKI is discovered with potent and selective activity against FLT3-mutant cell lines and primary patient samples. TTT-3002 is effective in vivo in several mouse tumor models of FLT3/ITD-associated AML with minimal toxicity.


2011 ◽  
Vol 35 (2) ◽  
pp. 237-242 ◽  
Author(s):  
Xia Yuan ◽  
Yi Zhang ◽  
Haijing Zhang ◽  
Jing Jin ◽  
Xiangyan Li ◽  
...  

Cancers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 5898
Author(s):  
Tao Yu ◽  
Junguo Cao ◽  
Montadar Alaa Eddine ◽  
Mahmoud Moustafa ◽  
Andreas Mock ◽  
...  

To date, there is no standard-of-care systemic therapy for the treatment of aggressive meningiomas. Receptor tyrosine kinases (RTK) are frequently expressed in aggressive meningiomas and are associated with poor survival. Ponatinib is a FDA- and EMA-approved RTK inhibitor and its efficacy in meningioma has not been studied so far. Therefore, we investigated ponatinib as a potential drug candidate against meningioma. Cell viability and cell proliferation of ponatinib-treated meningioma cells were assessed using crystal violet assay, manual counting and BrdU assay. Treated meningioma cell lines were subjected to flow cytometry to evaluate the effects on cell cycle and apoptosis. Meningioma-bearing mice were treated with ponatinib to examine antitumor effects in vivo. qPCR was performed to assess the mRNA levels of tyrosine kinase receptors after ponatinib treatment. Full-length cDNA sequencing was carried out to assess differential gene expression. IC50 values of ponatinib were between 171.2 and 341.9 nM in three meningioma cell lines. Ponatinib induced G0/G1 cell cycle arrest and subsequently led to an accumulation of cells in the subG1-phase. A significant induction of apoptosis was observed in vitro. In vivo, ponatinib inhibited meningioma growth by 72.6%. Mechanistically, this was associated with downregulation of PDGFRA/B and FLT3 mRNA levels, and mitochondrial dysfunction. Taken together, ponatinib is a promising candidate for targeted therapy in the treatment of aggressive meningioma.


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