scholarly journals Impact of the Breakpoint Region on the Leukemogenic Potential and the TKI Responsiveness of Atypical BCR-ABL1 Transcripts

2021 ◽  
Vol 12 ◽  
Author(s):  
Michele Massimino ◽  
Elena Tirrò ◽  
Stefania Stella ◽  
Livia Manzella ◽  
Maria Stella Pennisi ◽  
...  

Chronic Myeloid Leukemia (CML) is a hematological disorder characterized by the clonal expansion of a hematopoietic stem cell carrying the Philadelphia chromosome that juxtaposes the BCR and ABL1 genes. The ensuing BCR-ABL1 chimeric oncogene is characterized by a breakpoint region that generally involves exons 1, 13 or 14 in BCR and exon 2 in ABL1. Additional breakpoint regions, generating uncommon BCR-ABL1 fusion transcripts, have been detected in various CML patients. However, to date, the impact of these infrequent transcripts on BCR-ABL1-dependent leukemogenesis and sensitivity to tyrosine kinase inhibitors (TKIs) remain unclear. We analyzed the transforming potential and TKIs responsiveness of three atypical BCR-ABL1 fusions identified in CML patients, and of two additional BCR-ABL1 constructs with lab-engineered breakpoints. We observed that modifications in the DC2 domain of BCR and SH3 region of ABL1 affect BCR-ABL1 catalytic efficiency and leukemogenic ability. Moreover, employing immortalized cell lines and primary CD34-positive progenitors, we demonstrate that these modifications lead to reduced BCR-ABL1 sensitivity to imatinib, dasatinib and ponatinib but not nilotinib. We conclude that BCR-ABL1 oncoproteins displaying uncommon breakpoints involving the DC2 and SH3 domains are successfully inhibited by nilotinib treatment.

Author(s):  
Sezgi Kipcak ◽  
Buket Ozel ◽  
Cigir B. Avci ◽  
Leila S. Takanlou ◽  
Maryam S. Takanlou ◽  
...  

Background: Chronic myeloid leukemia (CML), is characterized by a reciprocal translocation t(9;22) and forms the BCR/ABL1 fusion gene, which is called the Philadelphia chromosome. The therapeutic targets for CML patients which are mediated with BCR/ABL1 oncogenic are tyrosine kinase inhibitors such as imatinib, dasatinib, and nilotinib. The latter two of which have been approved for the treatment of imatinib-resistant or intolerance CML patients. Mitotic catastrophe (MC) is one of the non-apoptotic mechanisms which frequently initiated in types of cancer cells in response to anti-cancer therapies; pharmacological inhibitors of G2 checkpoint members or genetic suppression of PLK1, PLK2, ATR, ATM, CHK1, and CHK2 can trigger DNA-damage-stimulated mitotic catastrophe. PLK1, AURKA/B anomalously expressed in CML cells, that phosphorylation and activation of PLK1 occur by AURKB at centromeres and kinetochores. Objective: The purpose of this study was to investigate the effect of dasatinib on the expression of genes in MC and apoptosis pathways in K562 cells. Methods: Total RNA was isolated from K-562 cells treated with the IC50 value of dasatinib and untreated cells as a control group. The expression of MC and apoptosis-related genes were analyzed by the qRT-PCR system. Results: The array-data demonstrated that dasatinib-treated K562 cells significantly caused the decrease of several genes (AURKA, AURKB, PLK, CHEK1, MYC, XPC, BCL2, and XRCC2). Conclusion: The evidence supply a basis to support clinical researches for the suppression of oncogenes such as PLKs with AURKs in the treatment of types of cancer especially chronic myeloid leukemia.


Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3587
Author(s):  
Benjamin Lebecque ◽  
Céline Bourgne ◽  
Véronique Vidal ◽  
Marc G. Berger

Chronic Myeloid Leukemia (CML) is a model to investigate the impact of tumor intra-clonal heterogeneity in personalized medicine. Indeed, tyrosine kinase inhibitors (TKIs) target the BCR-ABL fusion protein, which is considered the major CML driver. TKI use has highlighted the existence of intra-clonal heterogeneity, as indicated by the persistence of a minority subclone for several years despite the presence of the target fusion protein in all cells. Epigenetic modifications could partly explain this heterogeneity. This review summarizes the results of DNA methylation studies in CML. Next-generation sequencing technologies allowed for moving from single-gene to genome-wide analyses showing that methylation abnormalities are much more widespread in CML cells. These data showed that global hypomethylation is associated with hypermethylation of specific sites already at diagnosis in the early phase of CML. The BCR-ABL-independence of some methylation profile alterations and the recent demonstration of the initial intra-clonal DNA methylation heterogeneity suggests that some DNA methylation alterations may be biomarkers of TKI sensitivity/resistance and of disease progression risk. These results also open perspectives for understanding the epigenetic/genetic background of CML predisposition and for developing new therapeutic strategies.


BMC Cancer ◽  
2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Enza Di Felice ◽  
Francesca Roncaglia ◽  
Francesco Venturelli ◽  
Lucia Mangone ◽  
Stefano Luminari ◽  
...  

2013 ◽  
Vol 59 (2) ◽  
pp. 71-74
Author(s):  
Aliz-Beáta Tunyogi ◽  
I Benedek ◽  
Judit Beáta Köpeczi ◽  
Erzsébet Benedek ◽  
Enikő Kakucs ◽  
...  

Abstract Introduction: Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder; the molecular hallmark of the disease is the BCR-ABL gene rearrangement, which usually occurs as the result of a reciprocal translocation between chromosomes 9 and 22. Tyrosine kinase inhibitors (TKI) were the first drugs that targeted the constitutively active BCR-ABL kinase and it have become the standard frontline therapy for CML. Monitoring the treatment of CML patients with detection of bcr-abl transcript levels with real time qualitative polymerase chain reaction (RQ-PCR) is essential in evaluating the therapeutic response. Material and method: At the Clinical Hematology and BMT Unit Tîrgu Mureș, between 2008-2011, we performed the molecular monitoring of bcr-abl transcript levels with RQ-PCR in 16 patients diagnosed with CML. Results: We have 11 patients on imatinib treatment who achieved major molecular response. One patient lost the complete molecular response after 5 years of treatment. Two patients in blast crisis underwent allogeneic hematopoietic stem cell transplantation from identical sibling donors. The first patient is in complete molecular remission after 4 years of the transplant with mild chronic GVHD. The other patient had an early relapse with treatment refractory disease and died from evolution of the disease. Three patients with advanced phases of the disease present increasing transcript levels. We performed the dose escalation, and for two of them the switch to the second generation of TKI. Conclusions: Regular molecular monitoring of individual patients with CML is clearly desirable. It allows for a reassessment of the therapeutic strategy in cases of rising levels of BCR-ABL as an early indication of loss of response.


2011 ◽  
Vol 2011 ◽  
pp. 1-4
Author(s):  
B. Uz ◽  
O. Bektas ◽  
E. Eliacik ◽  
H. Goker ◽  
Y. Erbilgin ◽  
...  

The current treatment of chronic phase chronic myeloid leukemia (CML) consists of oral tyrosine kinase inhibitors (TKIs). However, high-risk CML may present with an aggressive course which may result in blastic crisis or a “difficult-to-manage” state with available treatments. The aim of this paper is to report a patient with complicated CML resistant to treatment and progressed despite the administration of bosutinib, imatinib mesylate, nilotinib, dasatinib, interferon alpha 2a, cytotoxic chemotherapy, and allogeneic hematopoietic stem cell transplantation. The striking point of this case story is that no Abl kinase domain mutation against TKIs has been detected during this very complicated disease course of CML. Meanwhile, challenging cases will always be present despite the hope and progress in CML in the TKI era.


Chemotherapy ◽  
2019 ◽  
Vol 64 (2) ◽  
pp. 81-93 ◽  
Author(s):  
Yingying Ma ◽  
Quanchao Zhang ◽  
Peiyan Kong ◽  
Jingkang Xiong ◽  
Xi Zhang ◽  
...  

With the advent of tyrosine kinase inhibitors (TKIs), the treatment of Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) has entered a new era. The efficacy of TKIs compared with other ALL treatment options is emphasized by a rapid increase in the number of TKI clinical trials. Subsequently, the use of traditional approaches, such as combined chemotherapy and even allogeneic hematopoietic stem cell transplantation (allo-HSCT), for the treatment of ALL is being challenged in the clinic. In light of the increased use of TKIs in the clinic, several questions have been raised. First, is it necessary to use intensive chemotherapy during the induction course of therapy to achieve a minimal residual disease (MRD)-negative status? Must a patient reach a complete molecular response/major molecular response before receiving allo-HSCT? Does MRD status affect long-term survival after allo-HSCT? Is auto-HSCT an appropriate alternative for allo-HSCT in those Ph+ ALL patients who lack suitable donors? Here, we review the recent literature in an attempt to summarize the current status of TKI usage in the clinic, including several new therapeutic approaches, provide answers for the above questions, and speculate on the future direction of TKI utilization for the treatment of Ph+ ALL patients.


HemaSphere ◽  
2019 ◽  
Vol 3 (S1) ◽  
pp. 152-153
Author(s):  
R.S. Alves ◽  
S.E. McArdle ◽  
J. Vadakekolathu ◽  
A.C. Gonçalves ◽  
P. Freitas-Tavares ◽  
...  

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