A BCR-ABL Kinase Activity-Independent Signaling Pathway in Chronic Myelogenous Leukemia

2007 ◽  
Author(s):  
Shaoguang Li
Keyword(s):  
Signaling Pathway ◽  
Chronic Myelogenous Leukemia ◽  
Kinase Activity ◽  
Myelogenous Leukemia ◽  
Abl Kinase

scholarly journals Blockade of the Bcr-Abl Kinase Activity Induces Apoptosis of Chronic Myelogenous Leukemia Cells by Suppressing Signal Transducer and Activator of Transcription 5–Dependent Expression of Bcl-XL

2000 ◽  
Vol 191 (6) ◽  
pp. 977-984 ◽  
Author(s):  
Machiko Horita ◽  
Enrique Jose Andreu ◽  
Adalberto Benito ◽  
Cristina Arbona ◽  
Cristina Sanz ◽  
...  
Keyword(s):  
Chronic Myelogenous Leukemia ◽  
Kinase Activity ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Myelogenous Leukemia ◽  
Leukemic Cells ◽  
Chemotherapeutic Drugs ◽  
Signal Transducer ◽  
Abl Kinase ◽  
Cd34 Cells

Bcr-Abl–expressing leukemic cells are highly resistant to apoptosis induced by chemotherapeutic drugs. Although a number of signaling molecules have been shown to be activated by the Bcr-Abl kinase, the antiapoptotic pathway triggered by this oncogene has not been elucidated. Here, we show that the interleukin 3-independent expression of the antiapoptotic protein, Bcl-xL, is induced by Bcr-Abl through activation of signal transducer and activator of transcription (Stat)5. Inhibition of the Bcr-Abl kinase activity in Bcr-Abl–expressing cell lines and CD34+ cells from chronic myelogenous leukemia (CML) patients induces apoptosis by suppressing the capacity of Stat5 to interact with the bcl-x promoter. Interestingly, after inhibition of the Bcr-Abl kinase, the expression of Bcl-xL is downregulated more rapidly in chronic phase than in blast crisis CML cells, suggesting an involvement of this protein in disease progression. Overall, we describe a novel antiapoptotic pathway triggered by Bcr-Abl that may contribute to the resistance of CML cells to undergo apoptosis.

scholarly journals Activation of the c-Jun N-terminal Kinase (JNK) Signaling Pathway Is Essential during PBOX-6-induced Apoptosis in Chronic Myelogenous Leukemia (CML) Cells

2002 ◽  
Vol 277 (21) ◽  
pp. 18383-18389 ◽  
Author(s):  
Margaret M. Mc Gee ◽  
Giuseppe Campiani ◽  
Anna Ramunno ◽  
Vito Nacci ◽  
Mark Lawler ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Chronic Myelogenous Leukemia ◽  
Myelogenous Leukemia ◽  
Jnk Signaling ◽  
Jnk Signaling Pathway ◽  
Induced Apoptosis

A Common Deletion Polymorphism in the BIM Gene Contributes to Intrinsic Imatinib Resistance in Chronic Myelogenous Leukemia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1666-1666
Author(s):  
Axel M Hillmer ◽  
King-Pan Ng ◽  
Charles Chuah ◽  
Wen Chun Juan ◽  
Tun-Kiat Ko ◽  
...  
Keyword(s):  
Chronic Myelogenous Leukemia ◽  
East Asian ◽  
Myelogenous Leukemia ◽  
Dependent Manner ◽  
Intrinsic Resistance ◽  
Deletion Polymorphism ◽  
Primary Resistance ◽  
Imatinib Resistance ◽  
Abl Kinase ◽  
Tki Resistance

Abstract Abstract 1666 The use of the tyrosine kinase inhibitor (TKI), imatinib (IM), to target the oncogenic BCR-ABL kinase has resulted in profound responses in patients with chronic phase (CP) chronic myelogenous leukemia (CML). However, a subset of patients do not respond to TKIs, and are deemed to have primary resistance. Importantly, patients with European LeukemiaNet (ELN)-defined ‘failure’ or ‘suboptimal response’ are at increased risk of poorer long-term outcomes. Little is known about mechanisms underlying primary resistance, where only a minority of patients have BCR-ABL kinase domain (KD) mutations. Interestingly, East-Asian CML patients are reported to have lower complete cytogenetic response rates compared to the West (∼50 vs 80% respectively, Au et al. 2009). We used massively parallel DNA sequencing of paired-end ditags to identify genetic factors associated with resistance in CML patient samples. We discovered a novel deletion polymorphism in the BIM gene that correlated with resistance, and which represented a common polymorphism in normal East-Asian (12.3% carriers), but not African or Caucasian (0%), populations (n=2465). BIM is a pro-apoptotic BCL2 family member, and plays a central role in CML pathophysiology. Here, BCR-ABL suppresses FoxO3a-mediated BIM transcription to maintain a survival advantage, while preventing BIM expression following BCR-ABL inhibition results in TKI resistance. Inspection of BIM gene structure suggested the polymorphism would result in mutually exclusive splicing of exon 3 (E3) vs 4 (E4), leading to decreased expression of BIM transcripts encoding the pro-apoptotic BH3 domain (found only in E4). To test this hypothesis, we constructed a minigene to measure E3 vs E4 splicing, and found the polymorphism decreased splicing to E4 over E3 by >5-fold. Importantly, primary CML cells exhibited the same phenomenon, since polymorphism-containing samples expressed lower levels of E4- vs E3-containing transcripts (p=0.008), while general BIM transcription was unaffected. Our observations suggested a novel mechanism for intrinsic TKI resistance. Here, upon IM exposure, polymorphism-containing CML cells would favor induction of E3- vs E4-containing BIM transcripts, decreased expression of BH3-containing BIM isoforms, and impaired apoptosis. To facilitate these studies, we identified a Japanese CML cell line, KCL22, which contained the polymorphism, and confirmed it had a decreased E4/E3 transcript ratio compared to cells without the polymorphism. KCL22 cells also had decreased induction of E4-containing transcripts following IM, as well as lower levels of BIMEL protein, a major BH3-containing BIM isoform. Consistent with prior reports, KCL22 cells were resistant to IM, despite effective BCR-ABL inhibition, and had impaired apoptotic signalling upon IM exposure. Importantly, and as predicted by our model, pharmacologic restoration of BH3 activity (using the BH3-mimetic drug, ABT-737) sensitized cells to IM-induced death. Next, we used zinc finger nuclease-facilitated gene targeting to precisely create the polymorphism in the BIM gene of IM-sensitive K562 CML cells. We generated subclones that were heterozygous or homozygous for the polymorphism, and confirmed a decreased E4/E3 ratio in these cells in a polymorphism-dosage-dependent manner. Polymorphism-containing cells exhibited decreased induction of E4-containing transcripts following IM exposure, as well as impaired upregulation of BIMEL protein, and diminished apoptotic cell death. As in KCL22 cells, ABT-737 enhanced the ability of IM to activate apoptosis in polymorphism-containing cells. Using an expanded East-Asian CML cohort (n=203), we found the polymorphism correlated with TKI resistance (defined as ‘failure’ or ‘suboptimal’ per ELN criteria) in CP patients treated with 400 mg IM daily (p=0.02). Further, patients with the polymorphism were more likely to have resistance in the absence of a KD mutation than those without (OR=2.24, 95% CI of 1.22–4.12). In sum, we have found an East-Asian polymorphism in BIM that is associated with intrinsic resistance to TKIs. Screening for this polymorphism may be useful in identifying patients at risk of TKI resistance; a resistance we show can be overcome by BH3 mimetics. Our findings may also apply to other cancers and proliferative disorders in which drug-sensitivity is BIM-dependent. Disclosures: No relevant conflicts of interest to declare.

Overcoming Resistance in Chronic Myelogenous Leukemia

2013 ◽  
pp. 306-312
Author(s):  
Michael J. Mauro
Keyword(s):  
Chronic Myelogenous Leukemia ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Point Mutations ◽  
Kinase Domain ◽  
Drug Binding ◽  
Myelogenous Leukemia ◽  
Novel Therapy ◽  
Abl Kinase ◽  
Clinical Resistance

Resistance in chronic myelogenous leukemia is an issue that has developed in parallel to the availability of rationally designed small molecule tyrosine kinase inhibitors to treat the disease. A significant fraction of patients with clinical resistance are recognized to harbor point mutations/substitutions in the Abl kinase domain, which limit or preclude drug binding and activity. Recent data suggest that compound mutations may develop as well. Proper identification of clinical resistance and prudent screening for all causes of resistance, ranging from adherence to therapy to Abl kinase mutations, is crucial to success with kinase inhibitor therapy. There is currently an array of Abl kinase inhibitors with unique toxicity and activity profiles available, allowing for individualizing therapy beginning with initial choice at diagnosis and as well informed choice of subsequent therapy in the face of toxicity or resistance, with or without Abl kinase domain mutations. Recent studies continue to highlight the merits of increasingly aggressive initial therapy to subvert resistance and importance of early response to identify need for change in therapy. Proper knowledge and navigation amongst novel therapy options and consideration of drug toxicities, individual patient characteristics, disease response, and vigilance for development of resistance are necessary elements of optimized care for the patient with chronic myelogenous leukemia.

Detection of c-abl tyrosine kinase activity in vitro permits direct comparison of normal and altered abl gene products

1985 ◽  
Vol 5 (11) ◽  
pp. 3116-3123
Author(s):  
J B Konopka ◽  
O N Witte
Keyword(s):  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Myelogenous Leukemia ◽  
Gene Products ◽  
Tyrosine Kinase Activity ◽  
Abl Kinase ◽  
Abl Tyrosine Kinase ◽  
Assay Conditions

The v-abl transforming protein P160v-abl and the P210c-abl gene product of the translocated c-abl gene in Philadelphia chromosome-positive chronic myelogenous leukemia cells have tyrosine-specific protein kinase activity. Under similar assay conditions the normal c-abl gene products, murine P150c-abl and human P145c-abl, lacked detectable kinase activity. Reaction conditions were modified to identify conditions which would permit the detection of c-abl tyrosine kinase activity. It was found that the Formalin-fixed Staphylococcus aureus formerly used for immunoprecipitation inhibits in vitro abl kinase activity. In addition, the sodium dodecyl sulfate and deoxycholate detergents formerly used in the cell lysis buffer were found to decrease recovered abl kinase activity. The discovery of assay conditions for c-abl kinase activity now makes it possible to compare P150c-abl and P145c-abl kinase activity with the altered abl proteins P160v-abl and P210c-abl. Although all of the abl proteins have in vitro tyrosine kinase activity, they differ in the way they utilize themselves as substrates in vitro. Comparison of in vitro and in vivo tyrosine phosphorylation sites of the abl proteins suggests that they function differently in vivo. The development of c-abl kinase assay conditions should be useful in elucidating c-abl function.

Differential Regulation of Pro- and Anti-Apoptotic Genes by Bcr-Abl in an In Vitro Experimental Model of Chronic Myelogenous Leukemia.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4244-4244
Author(s):  
Axel Gustavo Ulbrich ◽  
Ana Elisa B. Bueno-da-Silva ◽  
Gustavo P. Amarante-Mendes
Keyword(s):  
Tyrosine Kinase ◽  
Chronic Myelogenous Leukemia ◽  
Kinase Activity ◽  
Philadelphia Chromosome ◽  
Specific Inhibitor ◽  
Differential Regulation ◽  
Myelogenous Leukemia ◽  
Leukemic Cells ◽  
Regulation Mechanism ◽  
Efficient Treatment

Abstract Leukemic cells from patients with Philadelphia chromosome-positive chronic myelogenous leukemia (CML) are very resistant to apoptosis induced by DNA-damaging agents and other chemotherapeutic drugs, due to the presence of Bcr-Abl, a chimeric cytoplasmic tyrosine-kinase that confers both malignancy and resistance to apoptosis. Efficient treatment of CML can be achieved with a normal bone marrow transplant, which induces a graft-versus-leukemia response, and more recently by the use of the specific inhibitor imatinib mesylate (glivec. Novartis). Glivec blocks Bcr-Abl kinase activity and, as a consequence, the malignant cell dies by apoptosis. However most glivec-treated patients, mainly in the acute and blast phases, develop resistant forms of the disease. Since resistance to apoptosis in Bcr-Abl+ cells is probably related to the inhibition of mitochondrial release of cytochrome c, an obligatory step in most apoptotic pathways, we sought to investigate expression of Bcl-2 family genes in Bcr-Abl+, glivec-treated cells. By semi-quantitative RT-PCR we analyzed the gene expression of several pro- and anti-apoptotic molecules in the transduced cell line HL-60.Bcr-Abl and the wild-type HL-60, after a 1, 4 and 8h treatment with 10μM glivec. Bcr-Abl′s kinase activity is promptly inhibited by glivec (within 5 to 15min) and HL-60.Bcr-Abl cells begin to show mitochondrial depolarization 24h after treatment with the drug, dying 48h later, whereas no effects are observed in HL-60. Soon after glivec addition some genes are transcriptionally regulated in HL-60.Bcr-Abl cells. The major differences were observed for bcl-xL (2-fold reduction), c-flip (2-fold increase), bcl-w (30% increase) and mcl-1 (20% reduction). Some pro-apoptotic molecules such as noxa also displayed differential regulation in HL-60.Bcr-Abl cells. No differences were observed in HL-60 cells. In conclusion we describe a complex transcriptional regulation mechanism dependent on Bcr-Abl tyrosine-kinase activity, which has not been previously described by the use of microarrays, and could contribute to the understanding of the mechanisms involved in protection of apoptosis and drug resistance of Bcr-Abl+ cells.

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