scholarly journals Design, Synthesis and Biological Evaluation of Pentacyclic Triterpene Derivatives: Optimization of Anti-ABL Kinase Activity

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3535 ◽  
Author(s):  
Halil I. Ciftci ◽  
Mohamed O. Radwan ◽  
Safiye E. Ozturk ◽  
N. Gokce Ulusoy ◽  
Ece Sozer ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
K562 Cells ◽  
Biological Evaluation ◽  
Benzyl Ester ◽  
Myelogenous Leukemia ◽  
Pentacyclic Triterpene ◽  
Abl Kinase ◽  
Molecular Targeted Drug ◽  
Benzyl Esters

Imatinib, an Abelson (ABL) tyrosine kinase inhibitor, is a lead molecular-targeted drug against chronic myelogenous leukemia (CML). To overcome its resistance and adverse effects, new inhibitors of ABL kinase are needed. Our previous study showed that the benzyl ester of gypsogenin (1c), a pentacyclic triterpene, has anti-ABL kinase and a subsequent anti-CML activity. To optimize its activities, benzyl esters of carefully selected triterpenes (PT1–PT6), from different classes comprising oleanane, ursane and lupane, and new substituted benzyl esters of gypsogenin (GP1–GP5) were synthesized. All of the synthesized compounds were purified and charachterized by different spectroscopic methods. Cytotoxicity of the parent triterpenes and the synthesized compounds against CML cell line K562 was examined; revealing three promising compounds PT5, GP2 and GP5 (IC50 5.46, 4.78 and 3.19 μM, respectively). These compounds were shown to inhibit extracellular signal-regulated kinase (ERK) downstream signaling, and induce apoptosis in K562 cells. Among them, PT5 was identified to have in vitro activity (IC50 = 1.44 μM) against ABL1 kinase, about sixfold of 1c, which was justified by molecular docking. The in vitro activities of GP2 and GP5 are less than PT5, hence they were supposed to possess other more mechanisms of cytotoxicity. In general, our design and derivatizations resulted in enhancing the activity against ABL1 kinase and CML cells.

scholarly journals Emodin Exerts an Antiapoptotic Effect on Human Chronic Myelocytic Leukemia K562 Cell Lines by Targeting the PTEN/PI3K-AKT Signaling Pathway and Deleting BCR-ABL

2016 ◽  
Vol 16 (4) ◽  
pp. 526-539 ◽  
Author(s):  
Chun-Guang Wang ◽  
Liang Zhong ◽  
Yong-Li Liu ◽  
Xue-Jun Shi ◽  
Long-Qin Shi ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
K562 Cells ◽  
Imatinib Resistance ◽  
Abl Kinase ◽  
Myelocytic Leukemia ◽  
Novel Drugs ◽  
Alternative Drug ◽  
Drug Treatments

The BCR-ABL kinase inhibitor, imatinib mesylate, is the front-line treatment for chronic myeloid leukemia, but the emergence of imatinib resistance has led to the search for alternative drug treatments. There is a pressing need, therefore, to develop and test novel drugs. Natural products including plants, microorganisms, and halobios provide rich resources for discovery of anticancer drugs. In this article, we demonstrate that emodin inhibited the growth of K562 cells harboring BCR-ABL in vitro and in vivo, and induced abundant apoptosis, which was correlated with the inhibition of PETN/PI3K/Akt level and deletion of BCR-ABL. These findings suggest that emodin is a promising agent to kill K562 cells harboring BCR-ABL.

Identification and Functional Significance of Genes Regulated by Structurally Different ABL Kinase Inhibitors.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2860-2860
Author(s):  
Kousuke Nunoda ◽  
Tetsuzo Tauchi ◽  
Tomoiku Takaku ◽  
Masahiko Sumi ◽  
Seiichi Okabe ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Inhibition ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Specific Inhibitor ◽  
K562 Cells ◽  
Myelogenous Leukemia ◽  
Altered Expression ◽  
Abl Kinase ◽  
Abl Kinase Inhibitors

Abstract Imatinib is an ABL-specific inhibitor that binds with high affinity to the inactive conformation of the BCR-ABL tyrosine kinase and has been shown to be effective in the treatment of chronic myelogenous leukemia. Dasatinib is an ATP-competitive, dual-spesific SRC and ABL kinase inhibitor that can bind BCR-ABL in both the active and inactive conformations. From a clinical stand point, dasatinib is particular attractive because it has been shown to induce hematologic and cytogenetic responses in imatinib-resistant CML patients. In the view of the fact that the combination of imatinib and dasatinib shows the additive/synergistic growth inhibition on a wild type p210 BCR-ABL expressing cells, we reasoned that these ABL kinase inhibitors might induce the different molecular pathways. To address this question, we used DNA microarrays to identify genes whose transcription was altered by imatinib and dasatinib. K562 cells were cultured with imatinib or dasatinib for 16 hrs, and gene expression data was obtained from three independent microarray hybridizations. Almost all of the imatinib- and dasatinib- responsive genes appeared to be similarly increased or decreased in K562 cells; however, small subsets of genes were identified as selectively altered expression by either imatinib or dasatinib. The genes whose expression was affected by imatinib and dasatinib were categorized into different functional groups based on their biological function, and genes in the cell proliferation and apoptosis categories were examined in detail. Imatinib and dasatinib affected the expression of several cyclin-dependent kinases (CDK2, CDK4, CDK6, CDK8, and CDK9), cell division cycle genes (CDC6, CDC7, CDC25C, and CDC34), and cyclones (cyclin A2, C, D2, D3, E1, E2, F, G1, G2, and H). Imatinib and dasatinib also modulated the expression of apoptosis-related genes including APAF1, BAK1, BCL2, BCL10, MCL1, CASP3, and CASP6). One of the distinct genes which are selectively modulated by dasatinib are CDK2 and CDK8, which had a maximal fold reduction of <8-fold in microarray screen. Immunoblotting confirmed that gene expression changes induced only by dasatinib correlated with changes in protein expression. To assess the functional importance of dasatinib regulated genes, we used RNA interference to determine whether reduction of CDK2 and CDK8 affected the growth inhibition. The siRNA to CDK2 or CDK8 specifically reduced cdk2 or cdk8 in K562 cells. K562 cells pretreated with CDK2 or CDK8 siRNA showed the additive growth inhibition with imatinib but not with dasatinib. These finding demonstrate that the additive/synergistic growth inhibition by imatinib and dasatinib may be mediated by CDK2 and CDK8.

In Vitro and In Vivo Activity of the Src/Abl Kinase Inhibitor AP23464 and Analogs Against Activation Loop Mutants of KIT.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 793-793 ◽  
Author(s):  
Amie S. Corbin ◽  
Shadmehr Demehri ◽  
Ian J. Griswold ◽  
Chester A. Metcalf ◽  
William C. Shakespeare ◽  
...  
Keyword(s):  
Cell Lines ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Myelogenous Leukemia ◽  
Activation Loop ◽  
Wild Type ◽  
Abl Kinase ◽  
Ic50 Values

Abstract Oncogenic mutations of the KIT receptor tyrosine kinase have been identified in several malignancies including gastrointestinal stromal tumors (GIST), systemic mastocytosis (SM), seminomas/dysgerminomas and acute myelogenous leukemia (AML). Mutations in the regulatory juxtamembrane domain are common in GIST, while mutations in the activation loop of the kinase (most commonly D816V) occur predominantly in SM and at low frequency in AML. Several ATP-competitive kinase inhibitors, including imatinib, are effective against juxtamembrane KIT mutants, however, the D816V mutant is largely resistant to inhibition. We analyzed the sensitivities of cell lines expressing wild type KIT, juxtamembrane mutant KIT (V560G) and activation loop mutant KIT (D816V,F,Y and murine D814Y) to a potent Src/Abl kinase inhibitor, AP23464, and analogs. IC50 values for inhibition of cellular KIT phosphorylation by AP23464 were 5–11 nM for activation loop mutants, 70 nM for the juxtamembrane mutant and 85 nM for wild type KIT. Consistent with this, IC50 values in cell proliferation assays were 3–20 nM for activation loop mutants and 100 nM for wild type KIT and the juxtmembrane mutant. In activation loop mutant-expressing cell lines, AP23464, at concentrations ≤50 nM, induced apoptosis, arrested the cell cycle in G0/G1 and down-regulated phosphorylation of Akt and STAT3, signaling pathways critical for the transforming capacity of mutant KIT. In contrast, 500 nM AP23464 was required to induce equivalent effects in wild-type KIT and juxtamembrane mutant-expressing cell lines. These data demonstrate that activation loop KIT mutants are considerably more sensitive to inhibition by AP23464 than wild type or juxtamembrane mutant KIT. Non-specific toxicity in parental cells occurred only at concentrations above 2 μM. Additionally, at concentrations below 100 nM, AP23464 did not inhibit formation of granulocyte/macrophage and erythrocyte colonies from normal bone marrow, suggesting that therapeutic drug levels would not impact normal hematopoiesis. We also examined in vivo target inhibition in a mouse model. Mice were subcutaneously injected with D814Y-expressing (D816V homologous) murine mastocytoma cells. Once tumors were established, compound was administered three-times daily by oral gavage. One hour post treatment we observed >90% inhibition of KIT phosphorylation in tumor tissue. Following a three-day treatment regimen, there was a statistically significant difference in tumor size compared to controls. Thus, AP23464 analogs effectively target D816-mutant KIT both in vitro and in vivo and inhibit activation loop KIT mutants more potently than the wild type protein. These data provide evidence that this class of kinase inhibitors may have therapeutic potential for D816V-expressing malignancies such as SM or AML.

Targeting Drug-Resistant CML and Ph+-ALL with the Spectrum Selective Protein Kinase Inhibitor XL228.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 474-474 ◽  
Author(s):  
Neil P. Shah ◽  
Corynn Kasap ◽  
Ronald Paquette ◽  
Jorge Cortes ◽  
Javier Pinilla ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Kinase Inhibitor ◽  
Plasma Concentrations ◽  
Protein Kinase Inhibitor ◽  
Myelogenous Leukemia ◽  
Drug Resistant ◽  
Wild Type ◽  
Inhibition Of Proliferation ◽  
Abl Kinase

Abstract The fusion protein BCR-ABL is a hallmark of chronic myelogenous leukemia (CML) and Philadelphia-positive acute lymphocytic leukemia (Ph+-ALL), and has been demonstrated as the primary driver of these diseases. Control of CML for considerable periods of time has been achieved through use of selective ABL kinase inhibitors, particularly imatinib. Once patients fail imatinib therapy, they are commonly found to harbor a mutated and activated form of BCR-ABL which is unable to bind the inhibitor. A more recent ABL inhibitor, dasatinib, can block growth of cells harboring most of the imatinib-resistant mutations, but T315I and F317L mutations are often seen in patients relapsing after dasatinib therapy. Thus once a patient develops CML harboring these mutations, there are few therapeutic options available. XL228 is a potent multi-targeted protein kinase inhibitor with activity against IGF1R, src, and Abl. It displays low nanomolar biochemical activity against wild type Abl kinase (Ki = 5 nM), as well as the T315I form of Abl resistant to imatinib and dasatinib (Ki = 1.4 nM). XL228 also inhibits Aurora A with an IC50 of approximately 3 nM, demonstrating a more balanced inhibition profile compared to other dual Abl /Aurora inhibitors. CML and ALL cell lines were evaluated for sensitivity to XL228, and in each case the IC50 for inhibition of proliferation was less than 100 nM. XL228 inhibits phosphorylation of BCR-ABL and its substrate STAT5 in K562 cells in vitro with IC50s of 33 and 43 nM, respectively. Single-dose pharmacodynamics studies demonstrate a potent effect of XL228 on BCR-ABL signaling in K562 xenograft tumors. Phosphorylation of BCR-ABL was decreased by 50% at XL228 plasma concentrations of 3.5 μM; a similar decrease in phospho-STAT5 occurred at 0.8 μM plasma concentration. XL228 showed clear superiority to MK-0457, imatinib, and dasatinib in downregulating BCR-ABL phosphorylation in BaF3 cells expressing the T315I form of BCR-ABL in vitro (406 nM, 6912 nM, >10,000 nM, >10,000 nM, respectively), and in xenograft experiments in vivo. These results indicate that XL228 potently inhibits wild type and T315I forms of BCR-ABL, and provide a rationale for the clinical development of this agent for the treatment of patients with drug-resistant disease. A phase I dose escalation study of XL228 in subjects with CML or Ph+-ALL who have failed prior imatinib and dasatinib therapy has been initiated, focusing on safety/tolerability, pharmacodynamics, and pharmacokinetics. Pharmacodynamic assessments include a flow cytometry-based phospho-CrkL assay, quantitative PCR for BCR-ABL, and plasma markers of XL228 activity. An update on our clinical experience with XL228 in subjects resistant or intolerant to imatinib and dasatinib will be presented.

Quiescent Chronic Myelogenous Leukemia (CML) Cells Are Resistant to BCR-ABL Inhibitors but Preferentially Sensitive to BMS-214662, a Farnesyltransferase Inhibitor (FTI) with Unique Quiescent-Cell Selective Cytotoxicity.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1993-1993 ◽  
Author(s):  
Francis Y. Lee ◽  
Mei-Li Wen ◽  
Amy Camuso ◽  
Stephen Castenada ◽  
Krista Fager ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
Residual Disease ◽  
Human Tumor ◽  
K562 Cells ◽  
Myelogenous Leukemia ◽  
In Vivo Studies ◽  
Cell Populations ◽  
Progenitor Compartment

Abstract The major concern in the treatment of CML is resistance to the approved agent imatinib mesylate at all stages of disease, most commonly due to mutations in BCR-ABL (but other mechanisms have also been identified). Experimental agents such as dasatinib (BMS-354825), a novel, oral kinase inhibitor that targets BCR-ABL and SRC kinases, or AMN107, which targets BCR-ABL but not SRC, were designed to address all or parts of these mechanisms and are currently under clinical testing. A second concern in CML is persistence of BCR-ABL-positive cells or ‘residual disease’ in the majority of patients on imatinib therapy, including those with complete cytogenetic responses. Bone marrow studies reveal that the residual disease resides at least in part in the primitive CD34+ progenitor compartment, suggesting that imatinib may not be effective against these cell populations (Bhatia et al, Blood101:4701, 2003). Moreover, several imatinib-resistant ABL kinase domain mutations have been detected in CD34+/BCR-ABL+ progenitors (Chu et al, Blood105:2093, 2005), a scenario for eventual disease relapse. A hallmark of CD34+ primitive CML progenitors is quiescence (Elrick et al, Blood105:1862, 2005). We hypothesized that BCR-ABL inhibitors like imatinib may not be effective in killing CML cells in this non-proliferative state. This was tested by comparing cytotoxicity of imatinib or dasatinib in proliferating K562 cells and in cells forced into quiescence by nutrient depletion. Proliferating K562 cells were effectively killed by imatinib (IC50 250–500 nM) and dasatinib (IC50 <1.00 nM). However, cells in quiescent cultures were far more resistant (imatinib IC50 >5000 nM; dasatinib IC50 >12 nM), suggesting that these inhibitors may be less effective in eradicating quiescent CD34+ progenitors. BMS-214662 is a FTI in Phase I clinical development. Unlike many other FTI, BMS-214662 exhibits potent cytotoxic activity against a variety of human tumor cells, and uniquely, its cytotoxicity is highly selective against non-proliferating cancer cells of epithelial origin (Lee et al, Proceedings of the AACR42:260s, 2001). We now demonstrate similar selectivity in K562 CML cells. BMS-214662 was 68-fold more potent in killing quiescent (IC50 = 0.7 uM) than proliferating K562 cells (IC50 = 47.5 uM). Because BCR-ABL inhibitors and BMS-214662 target distinct cell populations (proliferating vs quiescent), there may be a positive therapeutic interaction when these agents are used in combination. In vitro studies in quiescent K562 cultures demonstrated that the combination of BMS-214662 and dasatinib, at concentrations readily achievable in the clinic, produced supra-additive cytotoxicity (% cell kill: dasatinib alone = 0%, BMS-214662 alone = 21%, combination = 71%). In vivo studies in K562 xenografts implanted SC in mice also showed that the combination of BMS-214662 and dasatinib produced a superior anti-leukemic activity than either dasatinib alone (P=0.0157) or BMS-214662 alone (P=0.0002). These results highlight the potential utility of BMS-214662 for targeting the quiescent progenitor compartment which, in combination with targeted agents such as dasatinib, address both BCR-ABL-dependent and -independent mechanisms of resistance, and may produce more durable responses and suppress the emergence of resistance.

A Study of the Binding Mode and the In Vitro Activity of the Protein Tyrosine Kinase Inhibitor SKI-606 in the BCR-ABL Positive Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2335-2335
Author(s):  
Tiziana Grafone ◽  
Simona Soverini ◽  
Gianluca Tasco ◽  
Manuela Mancini ◽  
Frank Boschelli ◽  
...  
Keyword(s):  
Protein Tyrosine Kinase ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Blast Crisis ◽  
K562 Cells ◽  
Binding Mode ◽  
Inactive Conformation ◽  
Abl Kinase ◽  
Cd34 Cells

Abstract Resistance to the BCR-ABL inhibitor imatinib mesylate (IM) is often caused by the selection of leukemic clones harboring mutations that destabilize the inactive conformation of BCR-ABL, to which IM preferentially binds, shifting the equilibrium toward the active kinase conformation. Hence the need for second -generation kinase inhibitors with a greater flexibility in binding to different BCR-ABL conformations. The 4-anilino-3 quinolinecarbonitrile SKI-606 is a novel Src and ABL kinase inhibitor. We report here that SKI-606 is a potent and antiproliferative agent when tested in K562 cell line and CD34+ cells from patients with chronic myeloid leukemia (CML) blast crisis. In K562 cells, SKI-606 treatment caused a dose-dependent decrease in cell viability accompanied by accumulation in subG1 phase, an effect not observed in BCR-ABL-negative HL-60 cells. Treatment of K562 with 100 nM SKI-606 for 24 hours caused a complete dephosphorylation of Lyn, Stat5 and Bcl-xl, while AKT and Bad phosphorylation was only diminished. Unexpectedly, the phosphorylation of BCR-ABL was less affected. SKI-606 treatment caused a shift to the subG1 phase also of CD34+ cells isolated from both IM-sensitive and resistant patients, the latter harboring the BCR-ABL mutations F359V, Y253H, E255V and E255K. The inhibitory concentration 50% (IC50) was 100 nM SKI-606 for Y253H, E255V, E255K and 1000nM for F359V. Cytofluorimetric analysis of cells from IM- sensitive CML patients indicated an accumulation in subG1 phase following treatment with SKI-606 alone or in combination with IM. Because the crystal structure of the BCR-ABL kinase domain in complex with SKI-606 has not yet been determined and the mode of binding of this inhibitor is unknown, we first used a molecular docking approach to determine SKI-606 binding mode to wild type (wt) form of the BCR-ABL kinase. We found that the interaction between SKI-606 and BCR-ABL was more stable when the activation loop was in the inactive conformation. Moreover, we found that SKI-606 retained the ability of efficiently binding all the above mentioned BCR-ABL variants, but not the T315I. Finally, we identified six BCR-ABL residues located around SKI-606 that, if mutated, could potentially be able to interfere with the SKI-606/BCR-ABL interaction: the charged residues K271, D381 and H361; the hydrophobic/aliphatic residues V299, A380 and M318. These data help refining the use of SKI-606 for treatment of BCR-ABL positive leukemias.

Chlorogenic acid inhibits Bcr-Abl tyrosine kinase and triggers p38 mitogen-activated protein kinase–dependent apoptosis in chronic myelogenous leukemic cells

Blood ◽  
2004 ◽  
Vol 104 (8) ◽  
pp. 2514-2522 ◽  
Author(s):  
Gautam Bandyopadhyay ◽  
Tanusree Biswas ◽  
Keshab C. Roy ◽  
Swapan Mandal ◽  
Chhabinath Mandal ◽  
...  
Keyword(s):  
Chlorogenic Acid ◽  
Cell Lines ◽  
Salivary Gland Tumor ◽  
K562 Cells ◽  
Myelogenous Leukemia ◽  
Mitogen Activated Protein Kinase ◽  
Leukemic Cells ◽  
Abl Kinase ◽  
Mitogen Activated Protein

Abstract We report that chlorogenic acid (Chl) induces apoptosis of several Bcr-Abl–positive chronic myelogenous leukemia (CML) cell lines and primary cells from CML patients in vitro and destroys Bcr-Abl–positive K562 cells in vivo. In contrast, this compound has no effect on the growth and viability of Bcr-Abl–negative lymphocytic and myeloid cell lines and primary CML cells. Sodium chlorogenate (NaChl) exhibits 2-fold higher efficiency in killing K562 cells compared with Chl. NaChl also induces growth inhibition of squamous cell carcinoma (HSC-2) and salivary gland tumor cells (HSG), although at 50-fold higher concentration. NaChl inhibits autophosphorylation of p210Bcr-Abl fusion protein rapidly. We demonstrate that p38 phosphorylation is increased in Bcr-Abl–positive cells after treatment with NaChl and closely paralleled the inhibition of Bcr-Abl phosphorylation. NaChl did not increase phosphorylation of p38 in Bcr-Abl–negative cells including HSC-2 and HSG that are responsive to this compound, indicating that p38 activation by NaChl is dependent on Bcr-Abl kinase inhibition. Inhibition of p38 activity by SB203580 significantly reduced NaChl-induced apoptosis of K562 cells, whereas activation of p38 by anisomycin augmented the apoptosis. These findings indicate that inhibition of Bcr-Abl kinase leading to activation of p38 mitogen-activated protein (MAP) kinase may play an important role in the anti-CML activity of Chl.

scholarly journals Leukemogenesis induced by wild-type and STI571-resistant BCR/ABL is potently suppressed by C/EBPα

Blood ◽  
2006 ◽  
Vol 108 (4) ◽  
pp. 1353-1362 ◽  
Author(s):  
Giovanna Ferrari-Amorotti ◽  
Karen Keeshan ◽  
Michela Zattoni ◽  
Clara Guerzoni ◽  
Giorgio Iotti ◽  
...  
Keyword(s):  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Kinase Domain ◽  
Drug Binding ◽  
Myelogenous Leukemia ◽  
Abl Kinase ◽  
Kinase Domain Mutation

Abstract Chronic phase–to–blast crisis transition in chronic myelogenous leukemia (CML) is associated with differentiation arrest and down-regulation of C/EBPα, a transcription factor essential for granulocyte differentiation. Patients with CML in blast crisis (CML-BC) became rapidly resistant to therapy with the breakpoint cluster region–Abelson murine leukemia (BCR/ABL) kinase inhibitor imatinib (STI571) because of mutations in the kinase domain that interfere with drug binding. We show here that the restoration of C/EBPα activity in STI571-sensitive or -resistant 32D-BCR/ABL cells induced granulocyte differentiation, inhibited proliferation in vitro and in mice, and suppressed leukemogenesis. Moreover, activation of C/EBPα eradicated leukemia in 4 of 10 and in 6 of 7 mice injected with STI571-sensitive or -resistant 32D-BCR/ABL cells, respectively. Differentiation induction and proliferation inhibition were required for optimal suppression of leukemogenesis, as indicated by the effects of p42 C/EBPα, which were more potent than those of K298E C/EBPα, a mutant defective in DNA binding and transcription activation that failed to induce granulocyte differentiation. Activation of C/EBPα in blast cells from 4 patients with CML-BC, including one resistant to STI571 and BMS-354825 and carrying the T315I Abl kinase domain mutation, also induced granulocyte differentiation. Thus, these data indicate that C/EBPα has potent antileukemia effects even in cells resistant to ATP-binding competitive tyrosine kinase inhibitors, and they portend the development of anti-leukemia therapies that rely on C/EBPα activation.

Effects of the Bcr/abl kinase inhibitors STI571 and adaphostin (NSC 680410) on chronic myelogenous leukemia cells in vitro

Blood ◽  
2002 ◽  
Vol 99 (2) ◽  
pp. 664-671 ◽  
Author(s):  
Benjamin M. F. Mow ◽  
Joya Chandra ◽  
Phyllis A. Svingen ◽  
Christopher G. Hallgren ◽  
Ellen Weisberg ◽  
...  
Keyword(s):  
Chronic Myelogenous Leukemia ◽  
Kinase Inhibitors ◽  
Prolonged Exposure ◽  
K562 Cells ◽  
Resistant Cell ◽  
Myelogenous Leukemia ◽  
Abl Kinase ◽  
Healthy Donors ◽  
Abl Kinase Inhibitors

Abstract The adenosine triphosphate binding-site–directed agent STI571 and the tyrphostin adaphostin are undergoing evaluation as bcr/abl kinase inhibitors. The current study compared the effects of these agents on the survival of K562 cells, bcr/abl-transduced FDC-P1 cells, and myeloid progenitors from patients with chronic myelogenous leukemia (CML) compared with healthy donors. Treatment of K562 cells with 10 μM adaphostin resulted in decreased p210bcr/ablpolypeptide levels in the first 6 hours, followed by caspase activation and accumulation of apoptotic cells in less than 12 hours. By 24 hours, 90% of the cells were apoptotic and unable to form colonies. In contrast, 20 μM STI571 caused rapid inhibition of bcr/abl autophosphorylation without p210bcr/abl degradation. Although this was followed by the inhibition of Stat5 phosphorylation and the down-regulation of Bcl-xL and Mcl-1, only 7% ± 3% and 25% ± 9% of cells were apoptotic at 16 and 24 hours, respectively. Instead, the cytotoxic effects of STI571 became more pronounced with prolonged exposure, with IC90values greater than 20 μM and 1.0 ± 0.6 μM after 24 and 48 hours, respectively. Consistent with these results, 24-hour adaphostin exposure inhibited CML granulocyte colony-forming units (CFU-G) (median IC50, 12 μM) but not normal CFU-G (median IC50, greater than 20 μM), whereas 24-hour STI571 treatment had no effect on CML or normal CFU-G. Additional experiments revealed that STI571-resistant K562 cells remained sensitive to adaphostin. Moreover, the combination of STI571 + adaphostin induced more cytotoxicity in K562 cells and in CML CFU-G than either agent alone did. Collectively, these results identify adaphostin as a mechanistically distinct CML-selective agent that retains activity in STI571-resistant cell lines.

scholarly journals Targeting USP47 overcomes tyrosine kinase inhibitor resistance and eradicates leukemia stem/progenitor cells in chronic myelogenous leukemia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hu Lei ◽  
Han-Zhang Xu ◽  
Hui-Zhuang Shan ◽  
Meng Liu ◽  
Ying Lu ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Progenitor Cells ◽  
Chronic Myelogenous Leukemia ◽  
Drug Targets ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Myelogenous Leukemia ◽  
Tki Resistance

AbstractIdentifying novel drug targets to overcome resistance to tyrosine kinase inhibitors (TKIs) and eradicating leukemia stem/progenitor cells are required for the treatment of chronic myelogenous leukemia (CML). Here, we show that ubiquitin-specific peptidase 47 (USP47) is a potential target to overcome TKI resistance. Functional analysis shows that USP47 knockdown represses proliferation of CML cells sensitive or resistant to imatinib in vitro and in vivo. The knockout of Usp47 significantly inhibits BCR-ABL and BCR-ABLT315I-induced CML in mice with the reduction of Lin−Sca1+c-Kit+ CML stem/progenitor cells. Mechanistic studies show that stabilizing Y-box binding protein 1 contributes to USP47-mediated DNA damage repair in CML cells. Inhibiting USP47 by P22077 exerts cytotoxicity to CML cells with or without TKI resistance in vitro and in vivo. Moreover, P22077 eliminates leukemia stem/progenitor cells in CML mice. Together, targeting USP47 is a promising strategy to overcome TKI resistance and eradicate leukemia stem/progenitor cells in CML.

Sign in / Sign up

Export Citation Format

Share Document