BCR-ABL truncation due to premature translation termination as a mechanism of resistance to kinase inhibitors

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 7028-7028
Author(s):  
C. Yeh ◽  
W. Ma ◽  
H. Kantarjian ◽  
Z. J. Zhang ◽  
J. Cortes ◽  
...  

7028 Background: The major mechanism underlying imatinib resistance in patients with chronic myeloid leukemia (CML) is clonal expansion of leukemic cells with point mutations in the BCR-ABL tyrosine kinase. We describe three novel ABL premature termination mutations leading to BCR-ABL truncation in leukemia patients with multidrug (imatinib/nilotinib/dasatinib) resistance. Methods: Peripheral blood or bone marrow samples from drug-resistant CML patients were collected. Total nucleic acids were purified and subjected to two rounds of PCR analysis, with the first PCR designed to eliminate amplification of the wild-type, non-translocated ABL gene. Bi-directional sequencing was then performed. HL60 cells (a Ph-negative myeloid leukemia cell line) and peripheral blood of healthy subjects were used as negative controls; a human CML cell line (K562) was used as a positive control. Results: We identified an exon 7 deletion in three CML patients, a 4-nt insertion (908insCAGG) near the exon 5/6 junction in one CML case, and an exon 6 point mutation (997C>T) in one patient with acute lymphoblastic leukemia (ALL). These mutations all create premature stop codons and cause termination at residues 381, 315, and 333, respectively, leading to truncated proteins with only the first quarter of the kinase domain (P-loop) or lacking the C-terminus of ABL including the A-loop. Conclusions: These novel mutations, and the previously documented 35-nt insertion in exon 8, may constitute a new class of mutations that 1) cause truncation of the BCR-ABL kinase; (2) abolish the regulatory element in the ABL kinase domain and the downstream C-terminal region; and (3) confer significant drug resistance. [Table: see text]

Blood ◽  
1985 ◽  
Vol 65 (1) ◽  
pp. 21-31 ◽  
Author(s):  
RC Stong ◽  
SJ Korsmeyer ◽  
JL Parkin ◽  
DC Arthur ◽  
JH Kersey

Abstract A cell line, designated RS4;11, was established from the bone marrow of a patient in relapse with an acute leukemia that was characterized by the t(4;11) chromosomal abnormality. The cell line and the patient's fresh leukemic cells both had the t(4;11)(q21;q23) and an isochromosome for the long arm of No. 7. Morphologically, all cells were lymphoid in appearance. Ultrastructurally and cytochemically, approximately 30% of the cells possessed myeloid features. The cells were strongly positive for terminal deoxynucleotidyl transferase. They were HLA-DR positive and expressed surface antigens characteristic for B lineage cells, including those detected by anti-B4, BA-1, BA-2, and PI153/3. Immunoglobulin gene analysis revealed rearrangements of the heavy chain and kappa chain genes. The cells lacked the common acute lymphoblastic leukemia antigen and antigenic markers characteristic of T lineage cells. The cells reacted with the myeloid antibody 1G10 but not with other myeloid monoclonal antibodies. Treatment with 12-O-tetradecanoyl- phorbol-13-acetate induced a monocyte-like phenotype demonstrated by cytochemical, functional, immunologic, and electron microscopic studies. The expression of markers of both early lymphoid and early myeloid cells represents an unusual phenotype and suggests that RS4;11 represents a cell with dual lineage capabilities. To our knowledge, RS4;11 is the first cell line established from t(4;11)-associated acute leukemia.


Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1414-1418
Author(s):  
MP Bodger ◽  
GL Mounsey ◽  
J Nelson ◽  
PH Fitzgerald

Bsp-1 is an IgM murine monoclonal antibody raised against the human erythroblastic leukemia cell line (HEL) that reacts with basophils but not neutrophils or eosinophils. Western blotting techniques showed that Bsp-1 reacts with a 45-kilodalton surface antigen on HEL cells. The distribution of Bsp-1 antigen on leukemic cells is confined to a basophilic leukemia cell line, KU812, chronic myeloid leukemia with basophilia, and some cases of acute undifferentiated leukemia. Bsp-1 might therefore be a useful reagent for the study of basophil function and differentiation.


Blood ◽  
1987 ◽  
Vol 69 (5) ◽  
pp. 1414-1418 ◽  
Author(s):  
MP Bodger ◽  
GL Mounsey ◽  
J Nelson ◽  
PH Fitzgerald

Abstract Bsp-1 is an IgM murine monoclonal antibody raised against the human erythroblastic leukemia cell line (HEL) that reacts with basophils but not neutrophils or eosinophils. Western blotting techniques showed that Bsp-1 reacts with a 45-kilodalton surface antigen on HEL cells. The distribution of Bsp-1 antigen on leukemic cells is confined to a basophilic leukemia cell line, KU812, chronic myeloid leukemia with basophilia, and some cases of acute undifferentiated leukemia. Bsp-1 might therefore be a useful reagent for the study of basophil function and differentiation.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2135-2135
Author(s):  
Hongyun Xing ◽  
Yuping Gong ◽  
Ting Liu

Abstract Abstract 2135 Objective To establish an imatinib resistant Bcr-Abl positive acute lymphoblastic leukemia (ALL) cell line in vitro and to study imatibin resistance in Ph+ ALL. The reversal of the imatinib resistance by rapamycin, the second generation tyrosine kinase inhibitor and proteasome inhibitor was studied. Methods Ph(+) ALL SUP-B15 cell line was cultured in gradually increasing concentrations of imatinib to generate the imatinib resistant cell line at 6 μM imatinib. The cytotoxic effect of imatinib and other drugs was analyzed by MTT assay. RT-PCR, flow cytometry, Western blot analyses of proteins, DNA sequence analysis of ABL kinase domain were used to clarify the possible mechanisms of the imatinib resistance in the SUP-B15/RI cell line. Results We established the imatinib resistant Ph+ ALL cell line. The fusion bcr-abl gene was 6.1 times as high as that of the parental sensitive cell, and the mdr1 gene also increased 1.7 times in SUP-B15/RI cell line by the RT-PCR detection. However, the expression of hoct1 Abcl–2 and topoIIα gene were no difference between two cell lines by the RT-PCR detection. A K362S point mutation in the Abl kinase domain of SUP-B15/RI was found. The detection of cell signaling pathway of PI3K/AKT/mTOR, RAS/RAF, NF-κBA JNK and STAT showed the expression of PTEN and 4EBP-1 was down-regulated, AKT, mTOR and P70S6K was up-regulated and the expression of other cell signaling pathways in SUP-B15/RI was similar to its parental sensitive cell line. Dasatinib, nilotinib, and bortezomib could inhibit proliferation of SUP-B15/RI cells at nM concentration. SUP-B15/RI cell line also showed partial resistance to dasatinib and nilotinib, but not bortezomib. The combination of imatinib with rapamycin had synergistic effect to the resistance cell line. Conclusion In vitro, we establish imatinib resistant Ph + ALL cell line. Overexpression of bcr-abl and mdr1 gene, K362S point mutation in ABL kinase domain and up-regulation of the cell signaling pathways of PI3K/AKT/mTOR, RAS/RAF in SUP-B15/RI cell line were involved in the resistance mechanisms. The SUP-B15/RI cell line was also resistant to the second generation tyrosine kinaeses dasatinib and nilotinib,not bortezomib in vitro. However, the combination of imatinib with rapamycin can partially overcome the resistance. Blockade of the ubiquitin-proteasome could be a promising pathway to overcome resistance to imatinib. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4375-4375
Author(s):  
Mayuko Goto ◽  
Ichiro Hanamura ◽  
Motohiro Wakabayashi ◽  
Hisao Nagoshi ◽  
Tomohiko Taki ◽  
...  

Abstract Abstract 4375 Leukemia cell lines are ubiquitous powerful research tools that are available to many investigators. In balanced chromosomal aberration in leukemia, a chimeric fusion gene formed by genes existing on breakpoints is frequently related to leukemogenesis. Cytogenetic abnormalities of chromosome band 12p13 are detected non-randomly in various hematological malignancies and usually involved TEL, which encodes a protein of the ETS transcription factor family. Chromosome band 22q11-12 is one of partners of translocation 12p13 and t(12;22)(p13;q11-12) results in fusion of TEL and MN1 or in just the partial inactivation of TEL. It is important to analyze precisely the breakpoint in a non-random translocation such as t(12;22)(p13;q11-12) and in addition it contributes to the better understanding of the molecular pathogenesis of leukemogenesis. In this study, we established a novel human myeloid leukemia cell line, AMU-AML1, having t(12;22) from a patient with acute myeloid leukemia with multilineage dysplasia and analyzed its characters. Mononuclear cells were isolated by Ficoll-Hypaque sedimentation from patient's bone marrow before initiation of chemotherapy and cultured in RPMI 1640 supplemented with 10% heat-inactivated fetal bovine serum (FBS). After 3 months, cell proliferation became continuous. The cell line, named AMU-AML1, was established. In AMU-AML1, the following pathogens were negative for EBV, CMV, HBV, HCV, HIV-1, HTLV-1 and mycoplasma. A doubling time of AMU-AML1 cells was about 96 hours. Proliferation of the cells was stimulated by rhG-CSF (10 ng/ml), rhGM-CSF (10 ng/ml), M-CSF (50 ng/ml), rhIL-3 (10 ng/ml) and rhSCF (100 ng/ml) but not by IL-5 (10 ng/ml), rhIL-6 (10 ng/ml), and rhEPO (5 U/ml). AMU-AML1 was positive for CD13, CD33, CD117 and HLA-DR, negative for CD3, CD4, CD8 and CD56 by flow cytometry analysis. G-banding combined with SKY analysis of AMU-AML1 cells showed single structural abnormality; 46, XY, t(12;22)(p13;q11.2). Double-color FISH using PAC/BAC clones listed in NCBI website and array CGH analyses indicated that the breakpoint in 12p13 was within TEL or telomeric to TEL and it of 22q11 was centromeric to MN1. A chimeric MN1-TEL transcript and fusion protein of MN1-TEL could not be detected by RT-PCR and western blot analysis. The wild type of MN1 protein was strongly expressed in AMU-AML1 compared with other leukemic cell lines with t(12;22), MUTZ-3 and UCSD/AML1. Our data suggest that AMU-AML1 had a t(12;22)(p13;q11.2) without fusion of MN1-TEL and the expression level of MN1 protein was relatively high, which might have some effects on leukemogenesis. In conclusion, AMU-AML1 is a useful cell line to analyze the biological consequences of the leukemic cells with t(12;22)(p13;q11.2) but no fusion of MN1-TEL. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4244-4244
Author(s):  
Tsuyoshi Nakamaki ◽  
Norimichi Hattori ◽  
Hidetoshi Nakashima ◽  
Takashi Maeda ◽  
Hirotsugu Ariizumi ◽  
...  

Abstract Pervious in vitro studies have shown that molecular alterations of BCR-ABL-positive leukemia cells such as amplification of BCR-ABL gene and/or mutation(s) of abl kinase domain cause resistant to imatinib. However recent study showed that alterations of imatinib bioavailability might be a important factor to cause clinical resistant in BCR-ABL-positive leukemia patients, showing a differences between in vivo and in vitro sensitivity to imatinib of BCR-ABL-positive cells. To analyze mechanism(s) of clinical resistance to imatinib and to overcome the resistance, we have sequentially established and characterized two leukemia cell lines from a patient with myeloid blastic crisis of chronic myeloid leukemia (CML) who showed progressively resistant to imatinib. Case report and establishment of cell lines: a 59-years-old women developed blastic crisis preceded by four years of chronic phase of CML. Increased blasts in crisis was positive for CD13, 33 and showed double Ph-chromosome in addition to complexed chromosomal alterations such as, add(3)(p13), add(3)(q11), add(5)(q11), der(19)(3;19) (p21;q13). After repeated courses of combination chemotherapy including, 600mg of imatinib was administered orally in combination with chemotherapeutic drugs. For a brief period Imatinib showed clinical effects and slowed the increase of BCR-ABL-positive cells, however myeloblast progressively increased in peripheral blood in spite of daily administration of imatinib and she died four months treatment with imatinib. Two myeloid leukemia cell lines, NS-1 and NS-2 were established, after obtaining informed consent, from peripheral blood at day 65 and day 95 after initiation of imatinib administration, respectively. Cell surface phenotype and karyotype of these cell lines were identical to original blasts. NS-1 and NS-2 cell lines were characterized compared with BCR/ABL-positive K562 erythroleukemia cell line as a control Quantitative analysis by real-time polymerase chain reaction showed that copy number of BCR-ABL transcript were 2.2 × 105 and 1.6 × 10 5/μg RNA in NS-1 and NS-2 respectively, showing slightly lower than those (5.8 × 105) in K562 cell line. Although nucleotide sequence analysis showed that a point mutation in abl kinase domain resulted in amino acid substitution pro310ser in NS-1 cell line, no additional mutation was found in NS-2 cell line. Western blot analysis showed levels of both 210 KD BCR-ABL protein and BCR-ABL phosphorylation were similar in NS-1, NS-2 and K562 cells. Although two hours incubation with 10 mM imatinibin vitro did not show any detectable difference in levels of phosphorylation of BCR-ABL protein between NS-1 and NS-2 cell lines, sensitivity to imatinib measured by MTT assay showed that IC50 was 0.1 mM, 0.5 mM and 1.0mMin NS-1, NS-2 and K562 cell lines respectively. The measured IC50 of both NH-1 and NH-2 cell lines were much lower than reported plasma concentrations achieved by oral administration of 600 mg of imatinib (above 10 μM). The present results suggest difference between in vivo and in vitro sensitivity to imatinib indicate that alteration of bioavailability of imatinib possibly involved in clinical resistance to this drug, accumulations of BCR-ABL gene amplification and/or mutation are not necessarily a major reason of progressive clinical resistance to imatinib in BCR-ABL positive leukemia.


Blood ◽  
1989 ◽  
Vol 74 (1) ◽  
pp. 369-373
Author(s):  
UR Kees ◽  
R Lukeis ◽  
J Ford ◽  
OM Garson

A human leukemia cell line, PER-255, was established from the bone marrow of a 5-year-old boy with features typical of lymphomatous T- acute lymphoblastic leukemia (T-ALL). The leukemic origin of cell line PER-255 is indicated by its cytochemical and immunologic similarity to the patient's fresh leukemic cells, which correspond to immature cortical thymocytes. Southern blot analysis showed that the IgJH genes were in germline configuration, whereas both alleles of the T-cell receptor-beta (TCR-beta) gene were rearranged in PER-255 cells, with identical rearrangements present in the patient's leukemic cells. Cytogenetic analysis of the cell line revealed a single abnormal clone with the karyotype 46,XY,t(7;10)(q32–34;q24),t(9;12) (p22;p12–13). Reciprocal translocations involving chromosome bands 7q32–36, containing the gene for the TCR-beta chain, have been reported for a number of tumors of T-cell origin. Translocations involving the 7q32–36 region appear to be nonrandomly associated with childhood T-ALL, whereas abnormalities of 9p and 12p have been reported to be nonrandomly involved in ALL but not specifically associated with the T- cell phenotype.


Blood ◽  
1985 ◽  
Vol 65 (1) ◽  
pp. 21-31 ◽  
Author(s):  
RC Stong ◽  
SJ Korsmeyer ◽  
JL Parkin ◽  
DC Arthur ◽  
JH Kersey

A cell line, designated RS4;11, was established from the bone marrow of a patient in relapse with an acute leukemia that was characterized by the t(4;11) chromosomal abnormality. The cell line and the patient's fresh leukemic cells both had the t(4;11)(q21;q23) and an isochromosome for the long arm of No. 7. Morphologically, all cells were lymphoid in appearance. Ultrastructurally and cytochemically, approximately 30% of the cells possessed myeloid features. The cells were strongly positive for terminal deoxynucleotidyl transferase. They were HLA-DR positive and expressed surface antigens characteristic for B lineage cells, including those detected by anti-B4, BA-1, BA-2, and PI153/3. Immunoglobulin gene analysis revealed rearrangements of the heavy chain and kappa chain genes. The cells lacked the common acute lymphoblastic leukemia antigen and antigenic markers characteristic of T lineage cells. The cells reacted with the myeloid antibody 1G10 but not with other myeloid monoclonal antibodies. Treatment with 12-O-tetradecanoyl- phorbol-13-acetate induced a monocyte-like phenotype demonstrated by cytochemical, functional, immunologic, and electron microscopic studies. The expression of markers of both early lymphoid and early myeloid cells represents an unusual phenotype and suggests that RS4;11 represents a cell with dual lineage capabilities. To our knowledge, RS4;11 is the first cell line established from t(4;11)-associated acute leukemia.


Blood ◽  
1989 ◽  
Vol 74 (1) ◽  
pp. 369-373 ◽  
Author(s):  
UR Kees ◽  
R Lukeis ◽  
J Ford ◽  
OM Garson

Abstract A human leukemia cell line, PER-255, was established from the bone marrow of a 5-year-old boy with features typical of lymphomatous T- acute lymphoblastic leukemia (T-ALL). The leukemic origin of cell line PER-255 is indicated by its cytochemical and immunologic similarity to the patient's fresh leukemic cells, which correspond to immature cortical thymocytes. Southern blot analysis showed that the IgJH genes were in germline configuration, whereas both alleles of the T-cell receptor-beta (TCR-beta) gene were rearranged in PER-255 cells, with identical rearrangements present in the patient's leukemic cells. Cytogenetic analysis of the cell line revealed a single abnormal clone with the karyotype 46,XY,t(7;10)(q32–34;q24),t(9;12) (p22;p12–13). Reciprocal translocations involving chromosome bands 7q32–36, containing the gene for the TCR-beta chain, have been reported for a number of tumors of T-cell origin. Translocations involving the 7q32–36 region appear to be nonrandomly associated with childhood T-ALL, whereas abnormalities of 9p and 12p have been reported to be nonrandomly involved in ALL but not specifically associated with the T- cell phenotype.


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