scholarly journals Bcr-abl signals to desensitize chronic myeloid leukemia cells to IFNα via accelerating the degradation of its receptor

Blood ◽  
2011 ◽  
Vol 118 (15) ◽  
pp. 4179-4187 ◽  
Author(s):  
Sabyasachi Bhattacharya ◽  
Hui Zheng ◽  
Christos Tzimas ◽  
Martin Carroll ◽  
Darren P. Baker ◽  
...  

Abstract Constitutive activity of Bcr-abl fusion protein kinase causes chronic myeloid leukemia (CML). Inhibitors of Bcr-abl such as imatinib mesylate have replaced the cytokine IFNα as the primary treatment for the management of patients with this malignancy. We found that pretreatment of CML cells with imatinib mesylate augments the antigrowth effects of IFNα. Furthermore, introduction of Bcr-abl into non-CML cells inhibits the cellular responses to IFNα. This inhibition is mediated via a mechanism that involves activation of protein kinase D2. The latter promotes an accelerated phosphorylation-dependent degradation of the interferon-α/β receptor 1 chain of the type I interferon receptor, leading to attenuation of IFNα signaling. We discuss the relationship between Bcr-abl activity and IFNα signaling as a molecular basis of the combination of inhibitors of Bcr-abl and IFNα for CML treatment.

Blood ◽  
2008 ◽  
Vol 111 (3) ◽  
pp. 1039-1043 ◽  
Author(s):  
Andreas Hochhaus ◽  
Brian Druker ◽  
Charles Sawyers ◽  
Francois Guilhot ◽  
Charles A. Schiffer ◽  
...  

Abstract Imatinib mesylate, a targeted inhibitor of BCR-ABL tyrosine kinase, is the standard of care for chronic myeloid leukemia (CML). A phase 2 trial of imatinib in late chronic-phase (CP) CML after interferon-α (IFNα) failure enrolled 532 patients, 454 with a confirmed diagnosis of CP CML. Median time from diagnosis was 34 months; median duration of imatinib treatment was 65 months. Cumulative best rates of major cytogenetic response (MCyR) and complete cytogenetic response (CCyR) were 67% and 57%, respectively. At the 5-year landmark, 184 (41%) of the 454 patients are in CCyR. At more than 6 years, 199 (44%) of the 454 patients remain on imatinib. Most responses occurred within 12 months of starting imatinib; however, some patients achieved initial MCyR and CCyR more than 5 years after imatinib initiation. Estimated rates of freedom from progression to accelerated phase (AP) and blastic phase (BP) and overall survival at 6 years were 61% and 76%, respectively. Both freedom from progression to AP/BP and overall survival (OS) were associated with cytogenetic response level at 12 months. No increase in rates of serious adverse events was observed with continuous use of imatinib for up to 6.5 years, compared with earlier time points. Imatinib continues to be an effective and safe therapy for patients with CP CML after failure of IFN.


2015 ◽  
Vol 7 ◽  
pp. e2015003 ◽  
Author(s):  
Grzegorz Helbig ◽  
Grazyna Bober ◽  
Marek Seweryn ◽  
Ryszard Wichary ◽  
Andrzej Tukiendorf ◽  
...  

Introduction. Imatinib mesylate (IM) remains a treatment of choice for chronic myeloid leukemia (CML) showing a remarkable efficacy and providing a perspective for a long disease-free survival. Due to the long-term administration of IM, the questions about the possible impact on the development of secondary malignancies (SM) are raised.Objective. To investigate the frequency and clinical outcome of secondary malignancies during IM therapy for CML.Material and Methods. The records of 221 CML patients treated with IM between 2003-2013 in single institution were reviewed. The Chi-squared test was used for statistic analysis.Results. Secondary malignancies developed in eight out of the 221 patients (3.6%) receiving IM for a median of 61 months (range, 10-137 months). Female/male ratio was 5/3. Two patients were diagnosed with their CML at accelerated phase whereas 6 had chronic phase. The median age at IM initiation was 58 years (range, 31-72 years).  Five of these 8 SM patients received IM after other treatments failure: interferon α (n=5), hydroxyurea (n=4) and cytarabine (n=1). Three patients received IM as a frontline therapy. All patients were on IM at 400mg daily at SM occurrence. The therapy for SM included surgery (n=3); chemotherapy only (n=3); and chemotherapy followed by radiotherapy (n=1). One patient did not receive treatment due to disseminated disease. At the time of SM development all patients were in hematologic and cytogenetic remission (CCR) of their CML and all patients continued their IM while receiving treatment for their SM.  Among 8 patients with SM, five patients are alive and remain in CCR on IM whereas 3 patients died due to SM. The observed incidence of SM was found to be comparable with that expected in the age-adjusted population (chi-squared=0.4; p=0.52).Conclusions. The association between IM therapy for CML and SM development has not been found. 


2007 ◽  
Vol 86 (3) ◽  
pp. 208-211 ◽  
Author(s):  
Shin Nakayama ◽  
Tokiko Nagamura-Inoue ◽  
Kazuaki Yokoyama ◽  
Nobuhiro Ohno ◽  
Jun Ooi ◽  
...  

2007 ◽  
Vol 179 (5) ◽  
pp. 935-950 ◽  
Author(s):  
K.G. Suresh Kumar ◽  
Hervé Barriere ◽  
Christopher J. Carbone ◽  
Jianghuai Liu ◽  
Gayathri Swaminathan ◽  
...  

Ligand-induced endocytosis and lysosomal degradation of cognate receptors regulate the extent of cell signaling. Along with linear endocytic motifs that recruit the adaptin protein complex 2 (AP2)–clathrin molecules, monoubiquitination of receptors has emerged as a major endocytic signal. By investigating ubiquitin-dependent lysosomal degradation of the interferon (IFN)-α/β receptor 1 (IFNAR1) subunit of the type I IFN receptor, we reveal that IFNAR1 is polyubiquitinated via both Lys48- and Lys63-linked chains. The SCFβTrcp (Skp1–Cullin1–F-box complex) E3 ubiquitin ligase that mediates IFNAR1 ubiquitination and degradation in cells can conjugate both types of chains in vitro. Although either polyubiquitin linkage suffices for postinternalization sorting, both types of chains are necessary but not sufficient for robust IFNAR1 turnover and internalization. These processes also depend on the proximity of ubiquitin-acceptor lysines to a linear endocytic motif and on its integrity. Furthermore, ubiquitination of IFNAR1 promotes its interaction with the AP2 adaptin complex that is required for the robust internalization of IFNAR1, implicating cooperation between site-specific ubiquitination and the linear endocytic motif in regulating this process.


2009 ◽  
Vol 33 (1) ◽  
pp. 170-173 ◽  
Author(s):  
Fermin M. Sanchez-Guijo ◽  
Jesus M. Hernandez ◽  
Eva Lumbreras ◽  
Patricia Morais ◽  
Carlos Santamaría ◽  
...  

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