scholarly journals Doxorubicin Differentially Induces Apoptosis, Expression of Mitochondrial Apoptosis-Related Genes, and Mitochondrial Potential in BCR-ABL1-Expressing Cells Sensitive and Resistant to Imatinib

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Ewelina Synowiec ◽  
Grazyna Hoser ◽  
Jolanta Bialkowska-Warzecha ◽  
Elzbieta Pawlowska ◽  
Tomasz Skorski ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Nadh Dehydrogenase ◽  
Genotoxic Stress ◽  
Mitochondrial Potential ◽  
Imatinib Resistance ◽  
Imatinib Resistant ◽  
Executioner Caspases ◽  
Apoptosis Inducing Factor ◽  
Increased Activity ◽  
Higher Sensitivity

Imatinib resistance is an emerging problem in the therapy of chronic myeloid leukemia (CML). Because imatinib induces apoptosis, which may be coupled with mitochondria and DNA damage is a prototype apoptosis-inducing factor, we hypothesized that imatinib-sensitive and -resistant CML cells might differentially express apoptosis-related mitochondrially encoded genes in response to genotoxic stress. We investigated the effect of doxorubicin (DOX), a DNA-damaging anticancer drug, on apoptosis and the expression of the mitochondrial NADH dehydrogenase 3 (MT-ND3) and cytochromeb(MT-CYB) in model CML cells showing imatinib resistance caused by Y253H mutation in theBCR-ABL1gene (253) or culturing imatinib-sensitive (S) cells in increasing concentrations of imatinib (AR). The imatinib-resistant 253 cells displayed higher sensitivity to apoptosis induced by 1 μM DOX and this was confirmed by an increased activity of executioner caspases 3 and 7 in those cells. Native mitochondrial potential was lower in imatinib-resistant cells than in their sensitive counterparts and DOX lowered it. MT-CYB mRNA expression in 253 cells was lower than that in S cells and 0.1 μM DOX kept this relationship. In conclusion, imatinib resistance may be associated with altered mitochondrial response to genotoxic stress, which may be further exploited in CML therapy in patients with imatinib resistance.

Proliferation Inhibition and Apoptosis Induction Of Imatinib Resistance Chronic Myeloid Leukemia Cells By Down-Regulated PPP2R5C

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 5158-5158
Author(s):  
Qi Shen ◽  
Sichu Liu ◽  
Yu Chen ◽  
Lijian Yang ◽  
Shaohua Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chronic Myeloid Leukemia ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Primary Cells ◽  
Healthy Individuals ◽  
Hoechst 33258 ◽  
Imatinib Resistance ◽  
Imatinib Resistant

Abstract Chronic myeloid leukemia (CML) is a hematopoietic stem cell disorder that occurs because of t(9;22)(q34;q11) translocations. The prognosis in CML improved markedly after introduction of abl tyrosine kinase inhibitors (TKI), still a lot of CML patients die due to abl mutation related drug resistance and the blast crisis, moreover, de novo or secondary TKI-resistance is a significant problem in CML. The aim of the study is to down-regulate the PPP2R5C gene expression in imatinib-sensitive or imatinib-resistant chronic myeloid leukemia (CML) cell lines: K562, K562R (imatinib resistance without abl gene mutation), 32D-Bcr-Abl WT (imatinib sensitive, murine CML cell lines with wild type abl gene) and 32D-Bcr-Abl T315I (imatinib resistance, with abl gene T315I mutation) and primary cells from CML patients by RNA interference, thereby inhibit the CML cells proliferation and induce apoptosis. PPP2R5C-siRNAs numbered 799 or 991 were obtained by chemosynthesis. Non-silencing siRNA control (SC)-treated, mock-transfected, untreated cells were used as controls. PPP2R5C expression in mRNA levels from CML cells were analyzed after siRNAs delivered by nucleofection using the real-time quantitative PCR. The PPP2R5C protein levels were analyzed by Western blotting. Cell proliferation in vitro was assayed by the cell count kit-8 method after treatment. The morphology and the percentage of apoptosis were revealed by Hoechst 33258 stain and flow cytometry (FCM). Bone marrow mononuclear cells (BM-MNCs) from healthy individuals were transferred by PPP2R5C-siRNA-991. BFU-E, CFU-Meg and CFU-GM were performed from PPP2R5C-siRNA-991 treated BM-MNCs by methyl cellulose semi-solid culturing method, to estimate the role of differentiation and proliferation in BM-MNCs after PPP2R5C-siRNA transfection. The results showed that both PPP2R5C-siRNA-799 and PPP2R5C-siRNA-991 took best silencing results after nucleofection in all of four cells and primary cells from CML patients. The reduction about 2 to 7 folds in PPP2R5C mRNA level was observed in PPP2R5C-siRNA799 or PPP2R5C-siRNA991 treated cells. And PPP2R5C protein expression inhibition rate reached 38.08%-55.26% at 48 or 72 h after treatment. The proliferation rates of PPP2R5C-siRNA-799 or 991 treated CML cells were significantly decreased at 72 h (P < 0.05). PPP2R5C-siRNA-799 or 991 treated CML cells lines showed a significantly increase in AnnexinV/PI-positive cells (apoptosis) (P < 0.05), similar results in the morphological changes of apoptosis were found by Hoechst 33258 staining test. PPP2R5C gene mRNA expression levels in BM-MNCs from healthy individuals were significantly lower than that in K562 cells (P < 0.05), and the expression level was not significant changed after PPP2R5C-siRNA-991 transfection. The formation of BFU-E, CFU-Meg and CFU-GM from BM-MNCs showed no significant difference between PPP2R5C-siRNA-991 treatment and MOCK control group (P > 0.05). In conclusions, suppression of PPP2R5C by RNA interference could inhibit the proliferation and induce the apoptosis effectively in CML cells either in imatinib sensitive or imatinib resistance cell lines, while no significant effect of PPP2R5C-siRNA on the proliferation and differentiation of BM-MNCs in vitro, suggesting that PPP2R5C-siRNA might specially target on the CML cells. Down-regulating the PPP2R5C gene expression might be considered as a new target therapeutic strategy in CML, especially in imatinib-resistant CML. Disclosures: Li: This work was supported by Grants from National Natural Science Foundation of China (30871091 and 91129720), the Collaborated grant for HK-Macao-TW of Ministry of Science and Technology (2012DFH30060), the Guangdong Science & Technology Project (2012B0506: Research Funding.

Study of different mutations in chronic myeloid leukemia in India and their co-relation with drug resistance.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 7083-7083
Author(s):  
Priti Mitra ◽  
Swati Dasgupta ◽  
Chinmay Kumar Basu ◽  
Firoj Hossain Gharami ◽  
Subrata Mandal ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Chromosomal Abnormalities ◽  
Mutation Screening ◽  
Resistance Mutation ◽  
Tyrosine Kinase Domain ◽  
Molecular Response ◽  
Imatinib Resistance ◽  
Imatinib Resistant ◽  
Resistant Mutation

7083 Background: Emergence of ABL point mutations is the most frequent cause for imatinib resistance in CML. Aim of our study is to investigate two potential resistance mechanisms i.e.,mutations of BCR-ABL tyrosine kinase domain (TKD) and Additional Chromosomal Abnormalities during TKI treatment in CML. Methods: Karyotyping and BCR-ABL TKD mutation screening are performed in 100 imatinib resistant CML patients who were on imatinib at the time of loss of hematologic response, cytogenetic or molecular response. Imatinib–Resistance Mutation Analysis (Qualitative) were detected by Nested RTPCR and Sanger’s Sequencing. In 100 cases, 34 received escalated imatinib, 34 nilotinib and another 32 dasatinib. Results: In 100 BCR-ABL positive imatinib, nilotinib and dasatinib resistant cases, 11 different BCR-ABL TKD mutations were detected. Analysis revealed no mutations-43 cases, M351T-12 cases, G250E-10 cases, F317L-8 cases, M244V-5 cases, E255K-4 cases, V379I-4 cases, F359V-3 cases, H396R-3 cases, Y253F-3 cases, E355G-3 cases, T315I-2 cases. 11 novel mutations (F317L, G250E, M244V, Y253F, E255K, M351T, F359V, H396R, V379I, E355G, T315I) conferring imatinib resistance, 10 nilotinib–resistant mutations (M244V, F359V, T315I, E355G, G250E) and 8 dasatinib-resistant mutations (H396R, F317L, H396R, T315I, M351T) were seen in our patient population. T315I was found more frequently in cases on dasatinib than on imatinib therapy. Conclusions: T315I which confers resistance to all TKIs was detected only in 2/100 patients who demonstrated loss of response in our population. As compared with other western studies, incidence of T315I mutation was very low in our study. In addition analysis of mutation patterns at baseline may help in stratifying patients for treatment. For cases with TKI resistance, mutation and ACA screening may play role in identifying patients with poorer prognosis. In our practice if nilotinib–resistant mutation was detected, dasatinib was preferred and for dasatinib-resistant mutation, nilotinib was preferred. We are planning for using bosutinib, panotinib and omacetaxine (SC route) in third line therapy in imatinib resistant different mutation positive chronic myeloid leukemia.

Dasatinib induces notable hematologic and cytogenetic responses in chronic-phase chronic myeloid leukemia after failure of imatinib therapy

Blood ◽  
2006 ◽  
Vol 109 (6) ◽  
pp. 2303-2309 ◽  
Author(s):  
Andreas Hochhaus ◽  
Hagop M. Kantarjian ◽  
Michele Baccarani ◽  
Jeffrey H. Lipton ◽  
Jane F. Apperley ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Therapeutic Option ◽  
Phase 1 ◽  
Treatment Options ◽  
Chronic Phase ◽  
Imatinib Resistance ◽  
Imatinib Resistant ◽  
Dose Modifications

AbstractAlthough imatinib induces marked responses in patients with chronic myeloid leukemia (CML), resistance is increasingly problematic, and treatment options for imatinib-resistant or -intolerant CML are limited. Dasatinib, a novel, highly potent, oral, multitargeted kinase inhibitor of BCR-ABL and SRC family kinases, induced cytogenetic responses in a phase 1 study in imatinib-resistant or -intolerant CML and was well tolerated. Initial results are presented from a phase 2 study of 186 patients with imatinib-resistant or -intolerant chronic-phase CML (CML-CP) designed to further establish the efficacy and safety of dasatinib (70 mg twice daily). At 8-months' follow-up, dasatinib induced notable responses, with 90% and 52% of patients achieving complete hematologic and major cytogenetic responses (MCyR), respectively. Responses were long lasting: only 2% of patients achieving MCyR progressed or died. Importantly, comparable responses were achieved by patients carrying BCR-ABL mutations conferring imatinib resistance. Dasatinib also induced molecular responses, reducing BCR-ABL/ABL transcript ratios from 66% at baseline to 2.6% at 9 months. Nonhematologic adverse events were generally mild to moderate, and most cytopenias were effectively managed with dose modifications. Cross-intolerance with imatinib was not evident. To conclude, dasatinib induces notable responses in imatinib-resistant or -intolerant CML-CP, is well tolerated, and represents a promising therapeutic option for these patients. This trial was registered at www.clinicaltrials.gov as CA180013.

scholarly journals Spectrum of BCR-ABL Mutations and Treatment Outcomes in Ethiopian Imatinib-Resistant Patients With Chronic Myeloid Leukemia

2021 ◽  
pp. 1187-1193
Author(s):  
Fisihatsion Tadesse ◽  
Getahun Asres ◽  
Abdulaziz Abubeker ◽  
Amha Gebremedhin ◽  
Jerald Radich
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Disease Progression ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Therapy Resistance ◽  
Common Mechanism ◽  
Second Line ◽  
Imatinib Resistance ◽  
Advanced Phase ◽  
Imatinib Resistant

PURPOSE Despite the successes achieved in chronic myeloid leukemia (CML) with tyrosine kinase inhibitor (TKI) therapy, resistance remains an obstacle. The most common mechanism of resistance is the acquisition of a point mutation in the BCR-ABL kinase domain. Few studies have reported African patients with CML in regard to such mutations. We here report the types of BCR-ABL mutations in Ethiopian imatinib-resistant patients with CML and their outcome. PATIENTS AND METHODS Patients with CML with a diagnosis of imatinib resistance who were tested for BCR-ABL mutation between 2014 and September 2019 were included. RESULTS A total of 962 cases of CML on imatinib therapy were reviewed and 164 cases of failure were found. Of these, only 31 cases (19%) had mutation analysis performed. Most cases (94%) were secondary failures. At the time of CML diagnosis, the median age was 33 years and the majority presented with features of advanced-phase disease. Of the 31 patients, 22 mutations were found (65%). The types of mutations detected were as follows: non–P-loop mutations 36% (11), P-loop mutations 13% (four), and alternatively spliced BCR-ABL variants 23% (seven). The splice variant frequently detected was BCR-ABL35INS (20%). Twenty-six of the 31 patients (84%) were switched to second-line TKIs, whereas in four patients (13%), imatinib dose escalation was done. Overall, the outcome revealed that 16 patients (52%) were alive with complete hematologic response, whereas 12 patients (39%) had died. All patients who expressed BCR-ABL135INS were treated with second-line TKIs, and two of them (33%) had died because of disease progression. CONCLUSION In Ethiopia, CML affects the young and point mutations were frequently detected in imatinib-resistant patients. BCR-ABL1 35INS was also prevalent and associated with disease progression.

scholarly journals Quantitative Proteomic Analysis of Plasma Exosomes to Identify the Candidate Biomarker of Imatinib Resistance in Chronic Myeloid Leukemia Patients

2021 ◽  
Vol 11 ◽  
Author(s):  
Mei-Yong Li ◽  
Cui Zhao ◽  
Lian Chen ◽  
Fang-Yi Yao ◽  
Fang-Min Zhong ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Proteomic Analysis ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Life Quality ◽  
Main Function ◽  
Label Free ◽  
Bioinformatics Analyses ◽  
Imatinib Resistance ◽  
Imatinib Resistant

BackgroundImatinib (IM), a tyrosine kinase inhibitor (TKI), has markedly improved the survival and life quality of chronic myeloid leukemia (CML) patients. However, the lack of specific biomarkers for IM resistance remains a serious clinical challenge. Recently, growing evidence has suggested that exosome-harbored proteins were involved in tumor drug resistance and could be novel biomarkers for the diagnosis and drug sensitivity prediction of cancer. Therefore, we aimed to investigate the proteomic profile of plasma exosomes derived from CML patients to identify ideal biomarkers for IM resistance.MethodsWe extracted exosomes from pooled plasma samples of 9 imatinib-resistant CML patients and 9 imatinib-sensitive CML patients by ultracentrifugation. Then, we identified the expression levels of exosomal proteins by liquid chromatography-tandem mass spectrometry (LC-MS/MS) based label free quantification. Bioinformatics analyses were used to analyze the proteomic data. Finally, the western blot (WB) and parallel reaction monitoring (PRM) analyses were applied to validate the candidate proteins.ResultsA total of 2812 proteins were identified in plasma exosomes from imatinib-resistant and imatinib-sensitive CML patients, including 279 differentially expressed proteins (DEPs) with restricted criteria (fold change≥1.5 or ≤0.667, p&lt;0.05). Compared with imatinib-sensitive CML patients, 151 proteins were up-regulated and 128 proteins were down-regulated. Bioinformatics analyses revealed that the main function of the upregulated proteins was regulation of protein synthesis, while the downregulated proteins were mainly involved in lipid metabolism. The top 20 hub genes were obtained using STRING and Cytoscape, most of which were components of ribosomes. Moreover, we found that RPL13 and RPL14 exhibited exceptional upregulation in imatinib-resistant CML patients, which were further confirmed by PRM and WB.ConclusionProteomic analysis of plasma exosomes provides new ideas and important information for the study of IM resistance in CML. Especially the exosomal proteins (RPL13 and RPL14), which may have great potential as biomarkers of IM resistance.

Six-year (yr) follow-up of patients (pts) with imatinib-resistant or -intolerant chronic-phase chronic myeloid leukemia (CML-CP) receiving dasatinib.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 6506-6506 ◽  
Author(s):  
Neil P. Shah ◽  
Hagop Kantarjian ◽  
Dong-Wook Kim ◽  
Andreas Hochhaus ◽  
Giuseppe Saglio ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Advanced Disease ◽  
Chronic Phase ◽  
Progression Free Survival ◽  
Dose Schedule ◽  
Imatinib Resistance ◽  
Once Daily ◽  
Free Survival ◽  
Imatinib Resistant

6506 Background: Dasatinib, a potent BCR-ABL inhibitor, is approved for use as 1st- and 2nd-line therapy for CML pts with newly diagnosed disease or resistance/intolerance to imatinib. This ongoing study in pts with imatinib-resistant/-intolerant CML provides the longest follow-up of a second-generation BCR-ABL inhibitor. Methods: Study design has been described (Shah, J Clin Oncol 2008). Pts with imatinib-resistant/-intolerant CML (N=670) were randomized to dasatinib 100 mg once daily (QD), 50 mg twice daily (BID), 140 mg QD, or 70 mg BID. Results: Five-yr data are reported here; 6-yr data will be presented. After a minimum of 5 yrs, 151 pts (74%) remain on QD dosing, 85 of whom (56%) are on ≥100 mg QD dosing. Overall, 205 pts (31%) remain on study therapy with 55 pts (53%) originally randomized to BID dosing having switched to QD dosing. For pts randomized to the 100 mg QD arm (n=167), progression-free survival (PFS) at 5 yrs is 57%, overall survival (OS) is 78% with an overall 5% rate of transformation to advanced disease. In exploratory analyses, 42% and 60% of pts had BCR-ABL levels ≤10% (International Scale) at 1 and 3 months (mos), respectively. In a landmark analysis, BCR-ABL ≤10% at 1 or 3 mos was associated with higher 5-yr PFS. For dasatinib 100 mg QD, nonhematologic adverse events (AEs; all grades) generally first occurred in <24 mos. Cumulative rates of AEs in the 100 mg QD arm were headache (33%), diarrhea (28%), fatigue (26%), and pleural effusion (24%). For dasatinib 100 mg QD, cytopenias (grades 3/4) generally first occurred in <12 mos. The most common hematologic AEs (grades 3/4) in the 100 mg QD arm were neutropenia (36%) and thrombocytopenia (24%). AEs were managed by dose/schedule modifications. Conclusions: Five-yr follow-up of pts who switched to dasatinib 100 mg QD after imatinib-resistance/intolerance shows high rates of PFS, and OS with an overall low rate of transformation. Exploratory analyses suggest that achievement of a fast and deep response (≤10% BCR-ABL) at 1 or 3 mos after initiation of dasatinib 100 mg QD may be associated with a higher PFS. Dasatinib 100 mg QD was generally well tolerated over 5 yrs. Six-yr data will be presented.

scholarly journals Impact of Baseline BCR-ABL Mutations on Response to Nilotinib in Patients With Chronic Myeloid Leukemia in Chronic Phase

2009 ◽  
Vol 27 (25) ◽  
pp. 4204-4210 ◽  
Author(s):  
Timothy Hughes ◽  
Giuseppe Saglio ◽  
Susan Branford ◽  
Simona Soverini ◽  
Dong-Wook Kim ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Phase Ii ◽  
Myeloid Leukemia ◽  
Chronic Phase ◽  
Cytogenetic Response ◽  
Molecular Response ◽  
Imatinib Resistance ◽  
Mutational Status ◽  
Imatinib Resistant

Purpose Nilotinib is a second-generation tyrosine kinase inhibitor indicated for the treatment of patients with chronic myeloid leukemia (CML) in chronic phase (CP; CML-CP) and accelerated phase (AP; CML-AP) who are resistant to or intolerant of prior imatinib therapy. In this subanalysis of a phase II study of nilotinib in patients with imatinib-resistant or imatinib-intolerant CML-CP, the occurrence and impact of baseline and newly detectable BCR-ABL mutations were assessed. Patients and Methods Baseline mutation data were assessed in 281 (88%) of 321 patients with CML-CP in the phase II nilotinib registration trial. Results Among imatinib-resistant patients, the frequency of mutations at baseline was 55%. After 12 months of therapy, major cytogenetic response (MCyR) was achieved in 60%, complete cytogenetic response (CCyR) in 40%, and major molecular response (MMR) in 29% of patients without baseline mutations versus 49% (P = .145), 32% (P = .285), and 22% (P = .366), respectively, of patients with mutations. Responses in patients who harbored mutations with high in vitro sensitivity to nilotinib (50% inhibitory concentration [IC50] ≤ 150 nM) or mutations with unknown nilotinib sensitivity were equivalent to those responses for patients without mutations (not significant). Patients with mutations that were less sensitive to nilotinib in vitro (IC50 > 150 nM; Y253H, E255V/K, F359V/C) had less favorable responses, as 13%, 43%, and 9% of patients with each of these mutations, respectively, achieved MCyR; none achieved CCyR. Conclusion For most patients with imatinib resistance and with mutations, nilotinib offers a substantial probability of response. However, mutational status at baseline may influence response. Less sensitive mutations that occurred at three residues defined in this study, as well as the T315I mutation, may be associated with less favorable responses to nilotinib.

scholarly journals Overexpression of miR-202 resensitizes imatinib resistant chronic myeloid leukemia cells through targetting Hexokinase 2

2018 ◽  
Vol 38 (3) ◽  
Author(s):  
Yingjun Deng ◽  
Xin Li ◽  
Jinxin Feng ◽  
Xiangliang Zhang
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Specific Inhibitor ◽  
Imatinib Resistance ◽  
Hexokinase 2 ◽  
Imatinib Resistant ◽  
First Choice ◽  
Long Term Treatment

Chronic myeloid leukemia (CML) is a myeloproliferative disease which uniquely expresses a constitutively active tyrosine kinase, BCR/ABL. As a specific inhibitor of the BCR-ABL tyrosine kinase, imatinib becomes the first choice for the treatment of CML due to its high efficacy and low toxicity. However, the development of imatinib resistance limits the long-term treatment benefits of it in CML patients. In the present study, we aimed to investigate the roles of miR-202 in the regulation of imatinib sensitivity in CML cell lines and the possible mechanisms involved in this process. We found miR-202 was down-regulated in seven CML cell lines by quantitative reverse-transcription PCR (qRT-PCR) analysis. Overexpression of miR-202 significantly suppressed proliferation rates of CML cells. By establishing imatinib resistant cell lines originating from K562 and KU812 cells, we observed expressions of miR-202 were down-regulated by imatinib treatments and imatinib resistant CML cell lines exhibited lower level of miR-202. On the contrary, imatinib resistant CML cell lines displayed up-regulated glycolysis rate than sensitive cells with the evidence that glucose uptake, lactate production, and key glycolysis enzymes were elevated in imatinib resistant cells. Importantly, the imatinib resistant CML cell lines were more sensitive to glucose starvation and glycolysis inhibitors. In addition, we identified Hexokinase 2 (HK2) as a direct target of miR-202 in CML cell lines. Overexpression of miR-202 sensitized imatinib resistant CML through the miR-202-mediated glycolysis inhibition by targetting HK2. Finally, we provided the clinical relevance that miR-202 was down-regulated in CML patients and patients with lower miR-202 expression displayed higher HK2 expression. The present study will provide new aspects on the miRNA-modulated tyrosine kinase inhibitor (TKI) sensitivity in CML, contributing to the development of new therapeutic anticancer drugs.

scholarly journals Mitochondrial mutagenesis in BCR-ABL1-expressing cells sensitive and resistant to imatinib.

2016 ◽  
Vol 63 (2) ◽  
Author(s):  
Janusz Blasiak ◽  
Grazyna Hoser ◽  
Jolanta Bialkowska-Warzecha ◽  
Elzbieta Pawlowska ◽  
Tomasz Skorski
Keyword(s):  
Oxidative Stress ◽  
Cell Lines ◽  
Copy Number ◽  
Myeloid Leukemia ◽  
Genotoxic Stress ◽  
Inhibitory Effects ◽  
Apoptotic Pathway ◽  
Imatinib Resistance ◽  
Mtdna Damage ◽  
Cml Model

Imatinib revolutionized the treatment of chronic myeloid leukemia (CML) with the expression of the BCR-ABL1 tyrosine kinase, but imatinib resistance is an emerging problem. Imatinib can hinder the inhibitory effects of BCR-ABL1 on mitochondrial apoptotic pathway, so mitochondrial mutagenesis can be important for its action. To explore the mechanisms of imatinib resistance we created a mouse-derived CML model cells consisting of parental 32D cells (P) and cells transfected with the BCR-ABL1 gene (S cells) or its variants with the Y253H or T315I mutations (253 and 315 cells, respectively), conferring resistance to imatinib. A fraction of the S cells was cultured in increasing concentrations of imatinib, acquiring resistance to this drug (AR cells). The 253, 315 and AR cells, in contrast to S cells, displayed resistance to imatinib. We observed that the T315I cells displayed greater extent of H2O2-induced mtDNA damage than their imatinib-sensitive counterparts. No difference in the sensitivity to UV radiation was observed among all the cell lines. A decrease in the extent of H2O2-induced mtDNA damage was observed during a 120-min repair incubation in all cell lines, but it was significant only in imatinib-sensitive and T315I cells. No difference in the copy number of mtDNA and frequency of the 3,867-bp deletion was observed and genotoxic stress induced by H2O2 or UV did not change this relationship. In conclusion, some aspects of mtDNA mutagenesis, including sensitivity to oxidative stress and DNA repair can contribute to imatinib resistance in BCR-ABL1-expressing cells.

Dasatinib induces significant hematologic and cytogenetic responses in patients with imatinib-resistant or -intolerant chronic myeloid leukemia in accelerated phase

Blood ◽  
2007 ◽  
Vol 109 (10) ◽  
pp. 4143-4150 ◽  
Author(s):  
Francois Guilhot ◽  
Jane Apperley ◽  
Dong-Wook Kim ◽  
Eduardo O. Bullorsky ◽  
Michele Baccarani ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Therapeutic Option ◽  
Phase 1 ◽  
Severe Neutropenia ◽  
Open Label ◽  
Imatinib Resistance ◽  
Imatinib Resistant

AbstractTreatment options are limited for patients with imatinib-resistant or -intolerant accelerated phase chronic myeloid leukemia (CML-AP). Dasatinib is a novel, potent, oral, multitargeted kinase inhibitor of BCR-ABL and SRC-family kinases that showed marked efficacy in a phase 1 trial of patients with imatinib-resistant CML. Results are presented for 107 patients with CML-AP with imatinib-resistance or -intolerance from a phase 2, open-label study further evaluating dasatinib efficacy and safety. At 8 months' minimum follow-up, 81%, 64%, and 39% of patients achieved overall, major (MaHR), and complete hematologic responses, respectively, whereas 33% and 24% attained major and complete cytogenetic remission. Of 69 patients who achieved MaHR, 7 progressed. Seventy-six percent of patients are estimated to be alive and progression-free at 10 months. Response rates for the 60% of patients with baseline BCR-ABL mutations did not differ from the total population. Dasatinib was well tolerated: most nonhematologic adverse events (AEs) were mild to moderate; no imatinib-intolerant patients discontinued dasatinib because of AEs. Although common (76% of patients with severe neutropenia), cytopenias were manageable through dose modification. In summary, dasatinib induced significant hematologic and cytogenetic responses in patients with imatinib resistance or intolerance, was well tolerated, and may represent a potent new therapeutic option for CML-AP. Further follow-up is warranted. This trial was registered at www.clinicaltrials.gov as #CA180005.

Sign in / Sign up

Export Citation Format

Share Document