scholarly journals Contribution of BCR-ABL molecular variants and leukemic stem cells in response and resistance to tyrosine kinase inhibitors: a review

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 1288
Author(s):  
Mohammad Al Hamad

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm generated by reciprocal chromosomal translocation, t (9; 22) (q34; q11) in the transformed hematopoietic stem cell. Tyrosine kinase inhibitors (TKIs) target the mature proliferating BCR-ABL cells, the major CML driver, and increase overall and disease-free survival. However, mutant clones, pre-existing or due to therapy, develop resistance against TKIs. BCR-ABL1 oncoprotein activates various molecular pathways including the RAS/RAF/MEK/ERK pathway, JAK2/STAT pathway, and PI3K/AKT/mTOR pathway. Stimulation of these pathways in TKI resistant CML patients, make them a new target. Moreover, a small proportion of CML cells, leukemic stem cells (LSCs), persist during the TKI therapy and sustain the disease in the patient. Engraftment of LSCs in the bone marrow niche and dysregulation of miRNA participate greatly in the TKI resistance. Current efforts are needed for determining the reason behind TKI resistance, identification, and elimination of CML LSC might be of great need for cancer cure.

Oncotarget ◽  
2017 ◽  
Vol 8 (30) ◽  
pp. 49451-49469 ◽  
Author(s):  
Simona Salati ◽  
Valentina Salvestrini ◽  
Chiara Carretta ◽  
Elena Genovese ◽  
Sebastiano Rontauroli ◽  
...  

2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S147-S147
Author(s):  
S Elzamly ◽  
O Padilla ◽  
M McAlice ◽  
M Gohar ◽  
S Gaur ◽  
...  

Abstract Introduction/Objective Chronic Myeloid Leukemia (CML) is a myeloproliferative neoplasm originating from malignant clonal proliferation of a pluripotent hematopoietic stem cell. CML is characterized by a reciprocal translocation between chromosomes 9 and 22, t(9;22)(q34;q11), that gives rise to an abnormal chromosome 22 called the Philadelphia (Ph) chromosome. The translocation results in the formation of a chimeric BCR-ABL1 fusion gene, which is the molecular hallmark of the disease. However, 5-10% of CML patients present with additional chromosomal abnormalities which is often considered a sign of clonal evolution, genetic instability, and is generally thought to portend a poor prognosis. Methods We present a case of CML with a rare 3- way translocation, t(3;9;22)(q21;q34;q11.2), who achieved a major molecular response on imatinib for 18 months. A review of the literature and Mitelman database search is presented focusing on the prognostic implications of this 3 way translocation in the era of tyrosine kinase inhibitors starting in 2001 till now. Results Twenty seven cases were reported, but the patient therapeutic response to imatinib and clinical outcome were only reported in 11 cases. Nine cases achieved a cytogenetic remission while the remaining two cases had an adverse outcome. Conclusion Taken in conjunction with the favorable outcome in our patient, we suggest that t(3;9;22) is not an adverse prognostic factor in the era of tyrosine kinase inhibitors.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4220-4220
Author(s):  
Yasuhito Nannya ◽  
Yoichi Imai ◽  
Akira Hangaishi ◽  
Mineo Kurokawa

Abstract Chronic myelogenous leukemia (CML) is a malignant clonal disorder of hematopoietic stem cells that results in increase in myeloid, erythroid cells, and platelets in the peripheral blood and marked myeloid hyperplasia in the bone marrow. This disorder is characterized by the specific cytogenetic abnormality, the Philadelphia (Ph) chromosome, which results from a balanced translocation between the long arms of chromosomes 9 and 22, generating the bcr/abl chimeric gene that expresses an abnormal fusion protein with altered tyrosine kinase activity. Imatinib mesylate (IM, Gleevec, Novartis, Basel, Switzerland), is a potent and selective competitive inhibitor of the BCR-ABL protein tyrosine kinase and has shown to induce a high rate of cytogenetic and hematologic response in patients with chronic phase (CP) CML both as initial therapy and as secondary therapy after previous interferon therapy failed. Because the pathophysiology of CML and the mechanism for the clinical effects by IM is relatively uniform among patients, simplification and generalization with mathematical models have been proposed and they have excellently simulated the regression of leukemic cells by IM therapy and the regrowth of CML cells after appearance of IM-resistant clones. These models are based on the assumption that the transition rate of leukemic stem cells or precursor cells to more differentiated fractions are profoundly diminished by the administration of IM. This assumption is sufficient to explain the response as long as the observation period is short. In contrast, the issue regarding the influence of IM on the self-reproduction rate of leukemic stem cells was not focused on in these models because this issue had little effect on short-term outcomes with IM. After a decade since the appearance of IM, accumulated observations of CML patients treated with IM revealed long-term effectiveness; novel transformations to accelerate phase or blastic crisis are rarely observed in patients who continue to receive 400mg/day of IM for five or six years. Our aim is to clarify the effect of IM on leukemic stem cell fractions by extending and modifying the existing models so that they are compatible with actual long-term outcomes of IM therapy. First, we demonstrated that sustained effectiveness of IM for over six years cannot be achieved unless a stem cell fraction of CML is decremented by IM. In order to estimate the degree of stem cell attack by IM, we computed the rate of novel generation of IM-resistant clones before and after IM administration. In this model, we presumed that this rate is proportional to the accumulated number of self-duplication of leukemic stem cells. In order to simulate the actual observation that the clonal evolution decrease annually after IM administration, we illustrated that the rate of self duplication is depleted to at one fourth or less with IM compared to without IM. With this simulation, we show that the tyrosine kinase inhibitors can eradicate malignant cells thus leading to the radical cure of the disease. We also showed that the achievement of major molecular response (MMR; defined as at least three-log reduction of bcr/abl positive clones in the peripheral blood) at the 18th month of IM therapy is roughly associated with the absence of resistant clones at the moment of IM administration, and is obviously linked to successful therapy of CML after IM therapy is launched. This provides the supportive evidence of the previously reported observation that MMR at 18th month is associated with long-term effectiveness. Our model underscores the significance of prompt elimination of leukemic stem cells in order to diminish the generation of novel resistant clones and accomplish complete cure of CML. Development of the evaluation system to quantify residual leukemic stem cells would verify this hypothesis and pursuit to maximal response including early administration of second-generation tyrosine kinase inhibitors would be justified.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 233-233
Author(s):  
Sebastian Giebel ◽  
Myriam Labopin ◽  
Norbert Claude Gorin ◽  
Denis Caillot ◽  
Thibaut Leguay ◽  
...  

Abstract Abstract 233 Outcome of patients with Ph-positive acute lymphoblastic leukemia (Ph+ ALL) improved markedly with the introduction of tyrosine kinase inhibitors (TKIs) used in combination with chemotherapy. However, despite very high rate of complete remissions the possibility of cure with conventional-dose treatment remains questionable. Hence, allogeneic hematopoietic stem cell transplantation (HSCT) is still considered a standard of care. Patients lacking appropriate donor are usually treated with TKI-based maintenance. Autologous HSCT could be an alternative approach, however, due to “negative” results of a series of prospective studies run in XX. century its use has been limited. The goal of the current analysis was to retrospectively analyze if results of autoHSCT for Ph+ ALL changed over time. Results of 171 autologous transplantations performed in the first complete remission between 1996–2010 and reported to the EBMT registry have been analyzed. Median patient age was 48.3 (19–65) years. Conditioning regimen was based on either TBI (63%) or chemotherapy (37%). Peripheral blood was used as a source of stem cells in 84% cases. With the median follow-up of 2 years, in the whole study group, the probability of the overall survival (OS) at 2 years was 45% (+/−4%) and leukemia-free survival (LFS) was 32% (+/−4%). The cumulative incidence of relapse (RI) and non-relapse mortality (NRM) was 54% (+/−4%) and 13% (+/−3%), respectively. LFS rates were comparable for TBI and chemotherapy-based conditioning (34% vs. 29%, p=0.53). As well, the source of stem cells had no impact on LFS (32% for PB vs. 33% for BM, p=0.91). The 2 year probability of LFS increased from 22% for transplants performed between 1996–2000 (n=70) to 32% between 2001–2006 (n=61) and 54% between 2007–2010 (n=40), p<0.001 (Fig). In respective periods the RI decreased from 65% to 47% and 46% (p=0.01), while NRM was 11%, 21% and 0% (p=0.03). In a multivariate analysis the year of transplantation (<2007 vs. 2007–2010) was the only factor independently influencing the risk of treatment failure (HR=2.98, 95%CI, 1.54–5.79; p=0.001). We conclude that results of autologous HSCT for Ph+ ALL improved markedly in recent period with more than half of patients being alive and leukemia-free at 2 years. Therefore, it appears than in the era of TKIs autologous HSCT may be considered potentially curative option. The advantage is probably associated with more profound responses achieved with TKIs, which, however requires confirmation in a separate analysis. As well, the role of post-transplant maintenance remains to be determined. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2011 ◽  
Vol 118 (16) ◽  
pp. 4353-4358 ◽  
Author(s):  
Dushyant Verma ◽  
Hagop Kantarjian ◽  
Sara S. Strom ◽  
Mary Beth Rios ◽  
Elias Jabbour ◽  
...  

Abstract Success of tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML) has given patients hope for a long disease-free-survival. A longer survival raises the question of late effects, including development of another malignancy. Records of 1445 patients with CML/myeloproliferative neoplasm or other hematologic malignancies treated with TKIs were reviewed to investigate frequency and characteristics of second malignancies (other than acute myeloid leukemia, acute lymphocytic leukemia, or myelodysplastic syndrome). The number of second cancers was compared with the number expected from the Surveillance, Epidemiology, and End Results database. After a median follow-up of 107 months (range, 13-362 months) after CML/myeloproliferative neoplasm diagnosis, 66 patients (4.6%) developed 80 second cancers, including skin (31%), prostate (15%), melanoma (13%), digestive system (10%), kidney (4%), thyroid (4%), breast (3%), chronic lymphocytic leukemia (3%), hepatobiliary (3%), and other cancers (14%). Excluding nonmelanoma skin cancers, 55 second cancers were seen in 51 (3.5%) of all patients treated. The risk of second cancer was lower than expected (observed-to-expected ratio, 0.6; 95% confidence interval, 0.44-0.81). Second cancers occur in a small percentage of patients receiving therapy with TKIs for hematologic malignancies, mostly CML. No evidence at the moment suggests that exposure to TKIs increases the risk of developing second cancers.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1023-1023
Author(s):  
Lothar Vassen ◽  
Daniel G. Tenen ◽  
Bert A. van der Reijden ◽  
Ulrich Duehrsen ◽  
Tarik Moroy ◽  
...  

Abstract Chronic myeloid leukemia (CML) is one of the most frequent leukemic diseases and invariably associated with a reciprocal t(9;22) translocation which creates a juxtaposition of the BCR and ABL genes to form the p230-, p190- or p210BCR-ABL constitutively active tyrosine kinases. This constitutive tyrosine kinase activity is the cause of CML and other leukemic diseases. CML is very efficiently treated with small molecule tyrosine kinase inhibitors, but CML is a stem cell initiated disease and surprisingly the leukemic stem cells cannot be eradicated by tyrosine kinase inhibitor treatment, resulting in a high risk of the development of therapy resistance. To design more successful therapies, it is primordial to understand the molecular mechanisms underlying this disease. Here we show that growth factor independent 1b (Gfi1b), also translocated in CML, is strongly induced in peripheral blood mononuclear cells (PBMCs) in patients with chronic- or acute myeloid leukemia (AML) as well as in patients suffering from myeloprolifarative syndrome (MPS) or B-lymphoblastic leukemia (B-ALL). Gfi1b is a transcriptional repressor essential for erythroid- and megacaryocytic cells, but also expressed in hematopoietic stem cells, early myeloid precursors and mature myeloid cells in peripheral blood. Interestingly, the expression of Gfi1b is further induced by long term treatment with tyrosine kinase inhibitors like Glivec, although the patients are phenotypically in remission. Additionally we describe a new splice variant of Gfi1b which is overrepresented in CML, AML and B-ALL, but not in MPS. Using a mouse model system we demonstrate, that Gfi1b strongly accelerates p210BCR-ABL induced leukemogenesis. We further show that Gfi1b inhibits the activity of PU.1, a key molecule in hematopoiesis and repressor of leukemogenesis. Our findings bear considerable significance with regard to the role of Gfi1b as an oncogene in human leukemia and to its possible value as a new target for leukemia therapy.


2013 ◽  
Vol 31 (31) ◽  
pp. 3987-3996 ◽  
Author(s):  
Justin F. Gainor ◽  
Alice T. Shaw

The success of tyrosine kinase inhibitors (TKIs) in select patients with non–small-cell lung cancer (NSCLC) has transformed management of the disease, placing new emphasis on understanding the molecular characteristics of tumor specimens. It is now recognized that genetic alterations in the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) define two unique subtypes of NSCLC that are highly responsive to genotype-directed TKIs. Despite this initial sensitivity, however, the long-term effectiveness of such therapies is universally limited by the development of resistance. Identifying the mechanisms underlying this resistance is an area of intense, ongoing investigation. In this review, we provide an overview of recent experience in the field, focusing on results from preclinical resistance models and studies of patient-derived, TKI-resistant tumor specimens. Although diverse TKI resistance mechanisms have been identified within EGFR-mutant and ALK-positive patients, we highlight common principles of resistance shared between these groups. These include the development of secondary mutations in the kinase target, gene amplification of the primary oncogene, and upregulation of bypass signaling tracts. In EGFR-mutant and ALK-positive patients alike, acquired resistance may also be a dynamic and multifactorial process that may necessitate the use of treatment combinations. We believe that insights into the mechanisms of TKI resistance in patients with EGFR mutations or ALK rearrangements may inform the development of novel treatment strategies in NSCLC, which may also be generalizable to other kinase-driven malignancies.


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