Mer Receptor Tyrosine Kinase Is A Potential Therapeutic Target in Acute Myeloid Leukemia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1317-1317
Author(s):  
Alisa B. Lee-Sherick ◽  
Kelly Menachof ◽  
Kristen M. Eisenman ◽  
Amy McGranahan ◽  
Colleen McGary ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Tyrosine Kinase ◽  
Cell Lines ◽  
Propidium Iodide ◽  
Receptor Tyrosine Kinase ◽  
Kinase Inhibitor ◽  
Control Cell ◽  
Flow Cytometric Analysis ◽  
Flow Cytometric ◽  
And Control

Abstract Abstract 1317 Acute myelogenous leukemia (AML) is difficult to treat successfully in both adult and pediatric patients using conventional chemotherapy. Mutated or aberrantly expressed proteins on the cell surface of myeloblasts provide a focus for targeted therapy which could potentially augment therapeutic outcome, decrease toxicity to normal tissues, and/or provide a therapy option for those who are not able to tolerate conventional therapy. We report here that the Mer receptor tyrosine kinase is upregulated in approximately 80% of AML cell lines and patient samples, and explore the therapeutic potential of Mer inhibition. We assessed the prevalence of Mer expression in AML. Western blot and flow cytometric analysis demonstrated expression of Mer in greater than 85% (12/14) of AML cell lines. Mer expression was also assessed at the time of diagnosis and relapse in both pediatric and adult patient samples using flow cytometry. We found that Mer was expressed on leukemic blasts in 80% of 36 pediatric and 100% of 10 adult patients at the time of diagnosis with AML. Additionally, 100% of 11 patients expressed Mer at the time of relapse. Furthermore, when analyzing patient samples at relapse compared to the same patient's diagnostic sample, there was a trend toward increased Mer expression. This is in contrast to normal bone marrow myeloid progenitors from healthy donors, which express little or no Mer. Using two independent shRNA constructs directed against Mer, we analyzed the effects of Mer inhibition in two Mer expressing AML cell lines. Mer knock-down and control cell lines were assessed for apoptosis by flow cytometry after serum starvation and staining with Yo-Pro-1 iodide and propidium iodide. Compared to AML cell lines transduced with a non-silencing control shRNA (shControl), cell lines expressing reduced levels of Mer protein demonstrated significantly more apoptosis (p<0.05). Additionally, when these cell lines were plated in equal number in methylcellulose, cell lines with reduced Mer expression demonstrated decreased colony forming potential compared to shControl cells (p<0.01). Mer knock-down and control cell lines were injected into NOD-SCID-gamma mice after sublethal irradiation and the mice were monitored for development of leukemia. Mice injected with myeloblasts expressing decreased levels of Mer demonstrated significantly prolonged symptom-free survival compared to mice transplanted with shControl AML cells (p<0.001). To further explore the effects of Mer inhibition in AML, we used a novel small molecule tyrosine kinase inhibitor (UNC1666), which has high specificity to Mer. Three Mer expressing AML cell lines were treated with UNC1666 in vitro; treatment reduced phosphorylation of Mer and the downstream signaling molecules ERK1/2 and STAT6. Additionally, treatment with UNC1666 resulted in significant induction of apoptosis (p<0.05) by flow cytometric analysis after staining with Yo-Pro-1 iodide and propidium iodide, and dose-dependent inhibition of colony formation in soft agar, when compared to vehicle treated cells In summary, the upregulation of Mer expression in patient samples and the functional effects on survival with Mer shRNA knockdown help validate Mer as a new and attractive AML therapeutic target. Furthermore, a novel Mer tyrosine kinase inhibitor decreased myeloblast cell survival, providing evidence that Mer is a druggable target in AML. Disclosures: Kireev: WO: Pyrazolopyrimidine Compounds for the Treatment of Cancer. WO Patent 2011146313, 2011, Pyrazolopyrimidine Compounds for the Treatment of Cancer. WO Patent 2011146313, 2011 Patents & Royalties. Liu:WO: Pyrazolopyrimidine Compounds for the Treatment of Cancer. WO Patent 2011146313, 2011, Pyrazolopyrimidine Compounds for the Treatment of Cancer. WO Patent 2011146313, 2011 Patents & Royalties. Wang:WO: Pyrazolopyrimidine Compounds for the Treatment of Cancer. WO Patent 2011146313, 2011, Pyrazolopyrimidine Compounds for the Treatment of Cancer. WO Patent 2011146313, 2011 Patents & Royalties. Frye:WO: Pyrazolopyrimidine Compounds for the Treatment of Cancer. WO Patent 2011146313, 2011, Pyrazolopyrimidine Compounds for the Treatment of Cancer. WO Patent 2011146313, 2011 Patents & Royalties. Graham:University of Colorado: This author has provisional patent considerations for iMer, This author has provisional patent considerations for iMer Patents & Royalties.

scholarly journals Chromosome doubling in Cattleya tigrina A. Rich

2019 ◽  
Vol 15 (11) ◽  
Author(s):  
Thays Saynara Alves Menezes-Sá ◽  
Maria de Fátima Arrigoni-Blank ◽  
Andréa Santos da Costa ◽  
Janay De Almeida Santos-Serejo ◽  
Arie Fitzgerald Blank ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Propidium Iodide ◽  
Chromosome Doubling ◽  
Flow Cytometric Analysis ◽  
Leaf Tissue ◽  
Stomatal Index ◽  
Chromosome Duplication ◽  
Flow Cytometric ◽  
Young Leaves ◽  
Commercial Value

Chromosome doubling induction in orchids may benefit their production for resulting in flowers of higher commercial value, larger size and higher content of substances that intensify the color and fragrance when compared with diploid orchids. This work aimed to induce and confirm artificial polyploidization, using flow cytometry and stomatal analysis. Explants were treated with colchicine at concentrations of 0, 2.5, 7.5, and 12.5 mM, for 24 and 48 hours and with oryzalin, at concentrations of 0, 10, 30, and 50 μM, for three and six days. For the flow cytometric analysis, a sample of leaf tissue was removed from each plant, crushed to release the nuclei and stained with propidium iodide. In addition to flow cytometry, the ploidy of the antimitotic treated plants was evaluated by stomata analysis. Young leaves were used where the density, functionality and stomatal index were evaluated. Colchicine provided induction of satisfactory polyploidy in C. tigrina at all concentrations and times of exposure, obtaining a greater number of polyploid individuals in the concentration of 12.5 mM for 48 hours. Oryzalin did not induce chromosome duplication at the tested concentrations.

Receptor Tyrosine Kinase-Like Orphan Receptor 1 (ROR1) - a Putative Diagnostic Marker for Chronic Lymphocytic Leukemia (CLL).

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1587-1587
Author(s):  
Sabrina Uhrmacher ◽  
Magdalena Hertweck ◽  
Julian Paesler ◽  
Felix Erdfelder ◽  
Alexandra Filipovich ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Tyrosine Kinase ◽  
Healthy Volunteers ◽  
Receptor Tyrosine Kinase ◽  
Peripheral Blood ◽  
Lymphocytic Leukemia ◽  
Orphan Receptor ◽  
Flow Cytometric

Abstract Abstract 1587 Poster Board I-613 In chronic lymphocytic leukemia (CLL) WNT signaling is constitutively active and several members of this signaling pathway are uniformely upregulated in these cells. Apart from classical WNT receptors like FZD and LRP6, receptor tyrosine kinase-like orphan receptor 1 (ROR1) has been shown to function as a receptor for WNT proteins, too. Furthermore, it could recently be demonstrated that ROR1 is frequently expressed on the surface of CLL cells and might therefore serve as a therapeutic target in this disease. However, so far only little is known about the expression status of this protein in different patients. Moreover, a diagnostic antibody for flow cytometric investigations is lacking. Thus, the aim of our study was to i) establish a directly labelled anti-ROR1 antibody for flow cytometry, ii) to confirm previous results on ROR1 expression in CLL, iii) to investigate ROR1 expression in different cell compartments and iv) correlate our findings to known markers of risk and disease progression. Peripheral blood of CLL patients as well as healthy volunteers was subjected to flow cytometric analysis. Besides standard determination of leukocyte subpopulations ZAP70 and CD38 status was assessed according to current diagnostic recommendations. In addition, ROR1 surface expression was first detected by flow cytometry using a specific primary antibody directed against ROR1 and a fluorescent labelled secondary antibody. Using this experimental setting we found that ROR1 is expressed on 63.4% of all neoplastic CLL cells and also on 30.5% of T cells in the peripheral CLL blood. In contrast, no ROR1 expression could be detected on NK cells, B cells, CD8+- or CD4+-T cells of healthy individuals. To improve the analytical technique the ROR1 antibody was directly conjugated with Phycoerythrin (PE) and the experiments were repeated. With the conjugated antibody we detected ROR1 expression on 97.1% of neoplastic CLL cells and virtually on no T lymphocytes. ROR1 expression levels correlated neither with the expression of ZAP70 nor with CD38. Again, we could not detect ROR1 expression on peripheral blood cells of our healthy volunteers. Taken together, ROR1 expression appears to be highly restricted to CLL cells. If in addition to CD5 and CD19 ROR1 detection is included into diagnostic flow cytometric panels the specificity and sensitivity of immunophenotypic CLL diagnostics may be greatly enhanced. Disclosures Hallek: Roche: Consultancy, Honoraria, Research Funding.

scholarly journals Fingolimod Is Cytotoxic in Acute Myeloid Leukemia Independent of Additional Chemotherapeutic Agents

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5126-5126
Author(s):  
Carter Thomas Davis ◽  
Arati V. Rao ◽  
Eross Guadalupe ◽  
Dale J. Christensen ◽  
J. Brice Weinberg
Keyword(s):  
Multiple Sclerosis ◽  
Flow Cytometry ◽  
Acute Myeloid Leukemia ◽  
Cell Line ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Flow Cytometric Analysis ◽  
Chemotherapeutic Agents ◽  
Flow Cytometric ◽  
Acute Myeloid

Abstract INTRODUCTION: Conventional treatment of acute myeloid leukemia (AML) remains largely unchanged for over thirty years. With poor overall survival and disease cure rates, novel therapies are needed. The SET oncoprotein has been implicated in AML as essential for proliferation through inhibition of the tumor suppressor protein phosphatase 2A (PP2A). Interaction between SET and PP2A leads to inactivation of PP2A, leaving cell survival and proliferation signals unchecked. PP2A has been postulated to be an important target in AML. Fingolimod (FTY720), an FDA approved drug for relapsing-remitting multiple sclerosis, is a sphingosine-1 phosphate receptor agonist that has off-target activity to activate PP2A. In this work, we show evidence of FTY720's efficacy in AML cells derived from cell lines and patients, and provide preliminary data regarding SET expression in AML cell lines. METHODS: Cytotoxicity experiments were performed using HL-60, THP-1, MV-4, and Kasumi-3 cell lines, as well as patient-derived samples of AML, obtained through an IRB-approved protocol. Cells were incubated overnight with varied concentrations of FTY720, azacitidine, idarubicin, cytarabine, or drugs in combination. After incubation, cells were analyzed by colorimetric assay. Percent cytotoxicity was estimated as a proportion of light absorbance compared with blank media and untreated control cells. Inhibitory concentration of 50% of cells (IC50) was estimated using GraphPad Prism software, version 6.0. Flow cytometry experiments for confirmation of cytotoxicity were also performed with antibodies against Annexin V and propidium iodide. For estimation of SET expression, we performed ELISA with antibodies against SETα and SETß and quantified measurements by light absorption. RESULTS: FTY720inhibits growth of AML cells independently in both cell lines and patient-derived samples. In the THP-1 cell line, we estimated the IC50 of FTY720 to be 3.4 μM (Figure 1). In the HL-60 cell line, we estimated the IC50 to be 2.5 μM. In patient-derived samples of AML, we had similar findings. The mean IC50 was 3.24 μM (SD = 1.32, n = 8). Flow cytometry of tested samples confirmed induction of both apoptosis and cell death within a 3-hour time frame (Figure 2). Samples were also incubated with combination of FTY720 and conventional cytotoxic chemotherapeutic agents used in AML (Table 1). In the HL-60 cell line, the following IC50s were estimated for these drugs: idarubicin (0.02 μM); cytarabine (0.6 μM); azacitidine (5.7 μM). In combination with FTY720, there was no appreciable change. Results of ELISA showed measurable but low SETα and SETß levels, when compared to a known positive control, the Ramos cell line for Burkitt's lymphoma (Table 2). In the MV-4 AML cell line, the SETα/ß ratio was 0.096. In Kasumi-3 cells, the α/ß ratio was measured at 0.063. DISCUSSION: These data support the assertion that FTY720 is a cytotoxic agent in AML. This effect is independent of other cytotoxic agents, as no additive or synergistic effect was demonstrated when drugs were combined. The micromolar cytotoxicity poses challenges to the adoption of this agent as an active drug in AML, as serum concentrations from currently prescribed doses in multiple sclerosis have been shown to achieve only nanomolar concentrations. It is notable that the volume of distribution of FTY720 is very high and over 90% is concentrated in blood cells, so actual cell concentrations may be substantially higher. Our work has not yielded the same results others have reported with increased SET α/ß ratios in AML cells. In other tumor types, high SET alpha ratios have been associated with higher SET activity; thus, these results would not be suggestive of such a role in AML. Despite our findings, the activity of FTY720 in these cells merits further investigation into SET expression in AML. We have recently a flow cytometric assay for SETα and SETß that can be used to quantify SET levels, and we plan to analyze patient samples used in cytotoxicity experiments to help identify the SET α/ß ratio in AML. We hope that these experiments will establish SET and PP2A as targets for drug development in AML. Figure 1 Cytotoxicity curve of FTY720 in THP-1 cells (n=3) Figure 1. Cytotoxicity curve of FTY720 in THP-1 cells (n=3) Figure 2 Flow cytometric analysis of FTY720 cytotoxicity in HL-60 cells. Figure 2. Flow cytometric analysis of FTY720 cytotoxicity in HL-60 cells. Disclosures Rao: Gilead, Inc.: Employment.

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 ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Cell Lines ◽  
Receptor Tyrosine Kinase ◽  
Kinase Inhibitor ◽  
Mutant Cell ◽  
Vehicle Control ◽  
Ic50 Value ◽  
Mutant Cells

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&lt;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.

UNC569 As Novel Small Molecule Mer Receptor Tyrosine Kinase Inhibitor for Treatment of ALL

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2589-2589 ◽  
Author(s):  
Sandra Christoph ◽  
Deborah DeRyckere ◽  
Susan Sather ◽  
Xiaodong Wang ◽  
Dmitri Kireev ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Cell Lines ◽  
Small Molecule ◽  
Receptor Tyrosine Kinase ◽  
Colony Formation ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Flow Cytometric Analysis ◽  
Cytotoxic Agents ◽  
Increased Risk

Abstract Abstract 2589 Introduction: Acute lymphoblastic leukemia (ALL) is one of the most common malignancies in children. Pediatric cure rates for ALL have dramatically increased in recent years as intensified therapeutic regimens have been developed. However, intensified therapy is associated with a significant and increased risk of short- and long-term toxicities. In addition, patients who relapse, do not reach remission, or have certain cytogenetic abnormalities have a poor prognosis and limited treatment options. Therefore, novel and less toxic therapies are needed. Tyrosine kinases are frequently abnormally regulated in cancer cells. Mer receptor tyrosine kinase is ectopically expressed in ALL cell lines and patient samples. Inhibition of Mer expression reduces pro-survival signaling, dramatically increases the sensitivity of leukemia cells to cytotoxic agents, and significantly delays development of leukemia in a mouse model. Thus, Mer tyrosine kinase inhibitors (TKIs) are excellent candidates for targeted therapies. We report here the first small molecule selective for Mer TK (UNC569) and characterization of its biochemical and anti-tumor activities in cell culture models of ALL. Methods: UNC569 is a substituted pyrazolopyrimidine that has been developed by a structure-based design and iterative medicinal chemistry from the known Mer/C52 cocrystal structure. Inhibition of Mer kinase activity by UNC569 was determined by a microfluidic capillary electrophoresis (MCE) assay in which phosphorylated and unphosphorylated substrate peptides were separated and analyzed through a LabChip EZ Reader. Western blot analysis of phosphorylated and total Mer protein was used to determine Mer inhibition by UNC569 in 697 (B-ALL) and Jurkat (T-ALL) cell lines. UNC569-mediated anti-leukemia activity was determined by detection of metabolically active cells using MTT reagent after 48 hours of exposure and by determining colony-formation in methylcellulose medium in the presence of UNC569. To investigate interactions with standard ALL therapies, apoptotic and dead cells were identified by flow cytometric analysis of cells stained with YO-PRO-1 and propidium iodide dyes after treatment with a chemotherapeutic agent alone or in combination with UNC569. Results: UNC569 is a novel small molecule Mer TKI with potent activity against Mer kinase (IC50 = 2.9 nM). In cell-based assays, UNC569 inhibited accumulation of phospho-Mer in both 697 and Jurkat ALL cells (IC50 <100 nM). Reduced proliferation and/or survival of ALL cells was also observed in 697 (IC50 = 0.91 ± 0.16 μM) and Jurkat (IC50 = 1.55 ± 0.19 μM) cultures. Treatment with UNC569 resulted in a statistically significant, dose-dependent decrease in colony-formation in Jurkat and 697 cell lines (60 ± 13.8 % (p = 0.01) and 29 ± 12.1 % (p = 0.01), respectively, relative to untreated cultures). Treatment of 697 cells with UNC569 in combination with etoposide resulted in a statistically significant increase in apoptotic and dead cells when compared with etoposide alone (43.3 ± 4.6 % vs 33.03 ± 0.73 %, p = 0.02). Treatment of Jurkat cells with a combination of UNC569 and methotrexate also resulted in a statistically significant increase in apoptotic and dead cells relative to methotrexate alone (26.9 ± 9.5 % vs 18.5 ± 5.7 %, p = 0.03). Conclusion: UNC569 is a highly effective Mer TKI that inhibits accumulation of the active phosphorylated form of Mer in B- and T-ALL cells. UNC569 mediates anti-leukemia activity against B- and T-ALL cells in culture and decreases colony-forming potential in methylcellulose. In addition, treatment with UNC569 sensitizes ALL cells to cytotoxic agents that are currently used as standard ALL therapies. Taken together, these data suggest that treatment with UNC569 may be a novel and effective ALL therapy and may be particularly effective in combination with cytotoxic therapies, thereby allowing for dose reduction and decreased incidence of toxic side effects. Disclosures: No relevant conflicts of interest to declare.

scholarly journals G-749 Promotes Receptor Tyrosine Kinase TYRO3 Degradation and Induces Apoptosis in Both Colon Cancer Cell Lines and Xenograft Mouse Models

2021 ◽  
Vol 12 ◽  
Author(s):  
Hae Dong Kim ◽  
Eun Jung Park ◽  
Eun Kyoung Choi ◽  
Seuk Young Song ◽  
Kwang-Lae Hoe ◽  
...  
Keyword(s):  
Colon Cancer ◽  
Tyrosine Kinase ◽  
Mouse Models ◽  
Cell Lines ◽  
Cancer Cell ◽  
Receptor Tyrosine Kinase ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Colon Cancer Cell ◽  
Colon Cancer Cell Lines

G-749 is an FLT3 kinase inhibitor that was originally developed as a treatment for acute myeloid leukemia. Some FLT3 kinase inhibitors are dual kinase inhibitors that inhibit the TAM (Tyro3, Axl, Mer) receptor tyrosine kinase family and are used to treat solid cancers such as non-small cell lung cancer (NSCLC) and triple-negative breast cancer (TNBC). AXL promotes metastasis, suppression of immune response, and drug resistance in NSCLC and TNBC. G-749, a potential TAM receptor tyrosine kinase inhibitor, and its derivative SKI-G-801, effectively inhibits the phosphorylation of AXL at nanomolar concentration (IC50 = 20 nM). This study aimed to investigate the anticancer effects of G-749 targeting the TAM receptor tyrosine kinase in colon cancer. Here, we demonstrate the potential of G-749 to effectively inhibit tumorigenesis by degrading TYRO3 via regulated intramembrane proteolysis both in vitro and in vivo. In addition, we demonstrated that G-749 inhibits the signaling pathway associated with cell proliferation in colon cancer cell lines HCT15 and SW620, as well as tumor xenograft mouse models. We propose G-749 as a new therapeutic agent for the treatment of colon cancer caused by abnormal TYRO3 expression or activity.

scholarly journals Effects of tyrosine kinase inhibitor-masitinib mesylate on canine mammary tumour cell lines

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Fulya Ustun-Alkan ◽  
Tülay Bakırel ◽  
Oya Üstüner ◽  
Ceren Anlas ◽  
Suzan Cinar ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitor ◽  
Dna Fragmentation ◽  
Cell Lines ◽  
Kinase Inhibitor ◽  
Flow Cytometric Analysis ◽  
Proliferation Index ◽  
Dependent Manner ◽  
Ki 67

Abstract Introduction Masitinib mesylate, a selective tyrosine kinase inhibitor of the c-KIT receptor, is used for the treatment of mast cell tumours in dogs. Masitinib has previously been investigated in various cancers; however, its potential anticancer effect in canine mammary tumours (CMTs) is unknown. In the present paper, we investigated the antiproliferative effect of masitinib in CMT cells and its possible mechanisms of action. Material and Methods The effect of masitinib on the proliferation of CMT-U27 and CMT-U309 cells was assessed by MTT assay and DNA fragmentation. Flow cytometric analysis was used to measure the effect of masitinib on apoptosis and the cell cycle. Additionally, vascular endothelial growth factor levels (VEGF) were measured, and the proliferation marker Ki-67 was visualised in immunocytochemical stainings in CMT cells. Results Treatment with masitinib inhibited the proliferation of CMT cells in a concentration-dependent manner. Maximal apoptotic activity and DNA fragmentation were observed at approximately IC50 of masitinib in both cell lines. In addition, cell cycle distribution was altered and VEGF levels and Ki-67 proliferation indices were decreased in masitinib-treated cells in comparison with control cells. Conclusion In this study, masitinib suppressed cell proliferation concomitantly via induction of apoptosis and cell cycle arrest by decreasing VEGF levels and the Ki-67 proliferation index in CMT-U27 and CMT-U309 cells in vitro, suggesting its potential as a therapeutic tool in the clinical setting of mammary cancer treatment in dogs.

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