scholarly journals Targeted Therapy for ETV6-RUNX1-Driven B-Cell Precursor Acute Lymphoblastic Leukemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 62-62
Author(s):  
Roel Polak ◽  
Marc B. Bierings ◽  
Cindy S. van der Leije ◽  
Rosanna E.S. van den Dungen ◽  
Mathijs A. Sanders ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Fusion Protein ◽  
Cell Viability ◽  
B Cell ◽  
Cell Survival ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Growth Arrest ◽  
Leukemic Cells ◽  
Cell Precursor

Abstract Background: Translocation t(12;21), resulting in the ETV6-RUNX1 fusion protein, is present in 25% of pediatric patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Despite the favorable prognostic parameters of this B-ALL subgroup, relapse and resistance to chemotherapeutics occur and treatment-induced side effects are considerable. The molecular mechanisms underlying ETV6-RUNX1-driven leukemia are largely unknown. Increased knowledge of these mechanisms is essential to develop novel therapeutic strategies to selectively target ETV6-RUNX1-positive leukemia. Objectives: This study aims to identify and target the molecular drivers behind ETV6-RUNX1-positive BCP-ALL. Results: Gene expression profiling of leukemic blasts of 654 ALL patients revealed that the class III PI3-kinase Vps34, an important regulator of autophagy, was exclusively up-regulated in ETV6-RUNX1-positive compared to ETV6-RUNX1-negative BCP-ALL patients (2.7-fold; p ≤ 10-30). In addition, ectopic expression of ETV6-RUNX1 in cord blood-derived hematopoietic progenitor cells (CB-HPCs) significantly induced expression of Vps34 1.3-fold already 40 hours after transduction (p ≤ 0.05). This suggests that the Vps34-autophagy pathway is activated by ETV6-RUNX1, which may mechanistically explain the leukemogenic and pro-survival properties ascribed to ETV6-RUNX1. In correspondence, Ingenuity Pathway Analysis (IPA) predicted a pro-survival and pro-proliferative phenotype in ETV6-RUNX1 transduced CB-HPCs and highlighted a network of up-regulated transcription factors, including HEY1, EGR1, GATA1 and GATA2 (2 – 25-fold up-regulation; p ≤ 0.05). Luciferase reporter assays revealed that not only the ETV6-RUNX1 fusion protein, but also the ETV6-RUNX1-induced target genes HEY1, EGR1 and GATA1 positively regulate Vps34 promoter activity (5 – 13-fold up-regulation; p ≤ 0.01).Lentiviral knockdown experiments were performed to elucidate the importance of Vps34 expression in ETV6-RUNX1-positive BCP-ALL cells. Knockdown of all Vps34 transcript variants, with two independent constructs, led to complete growth arrest of the ETV6-RUNX1-positive cell lines REH and AT2, while this only led to a decrease in proliferation of the ETV6-RUNX1-negative cell line NALM6. This growth arrest was caused by a significant induction of apoptosis (more than 4-fold 7 days after transduction; p ≤ 0.001) and a significantly reduced percentage of cycling cells (1.3-fold 7 days after transduction; p ≤ 0.05). Analysis of p62 protein expression by western blot and reverse phase protein arrays revealed that the levels of autophagy were significantly higher in ETV6-RUNX1-positive compared to ETV6-RUNX1-negative BCP-ALL patients (p ≤ 0.001). In addition, knockdown of ETV6-RUNX1 and Vps34 significantly reduced autophagy, quantified with confocal microscopy, in ETV6-RUNX1-positive cells with 50% and 84%, respectively (p ≤ 0.01). Furthermore, pharmacological inhibition of autophagy with hydroxychloroquine (HCQ) significantly reduced cell viability of BCP-ALL cell lines and primary patient-derived BCP-ALL cells (p ≤ 0.001). Treatment of the ETV6-RUNX1-positive BCP-ALL cell lines REH and AT2 with 20 µg/mL HCQ resulted in a 82% and 95% reduced cell viability, while the viability of ETV6-RUNX1-negative BCP-ALL cell lines and T-ALL cell lines were reduced to a lesser extent (NALM6: 43%; TOM-1: 50%; Loucy: 40%; Jurkat: 0%). Importantly, HCQ selectively sensitized ETV6-RUNX1-positive leukemic cells to L-asparaginase treatment in clinically relevant concentrations. Treatment of primary ETV6-RUNX1-positive patient cells with 10 µg/mL HCQ resulted in a 70% reduction in cell survival during L-asparaginase exposure (p ≤ 0.01). This sensitization was not observed in ETV6-RUNX1-negative BCP-ALL cells. Conclusion: The ETV6-RUNX1 fusion protein activates autophagy via Vps34, which is essential for survival and proliferation of ETV6-RUNX1-positive cells. Inhibition of autophagy in primary ETV6-RUNX1-positive leukemic cells inhibited cell survival and sensitized these cells to L-asparaginase treatment. These results indicate that autophagy inhibition may provide a novel means to sensitize L-asparaginase-resistant ETV6-RUNX1-positive BCP-ALL patients. Disclosures No relevant conflicts of interest to declare.

Chemo-sensitivity in a panel of B-cell precursor acute lymphoblastic leukemia cell lines, YCUB series, derived from children

2009 ◽  
Vol 33 (10) ◽  
pp. 1386-1391 ◽  
Author(s):  
Hiroaki Goto ◽  
Takuya Naruto ◽  
Reo Tanoshima ◽  
Hiromi Kato ◽  
Tomoko Yokosuka ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
B Cell ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
Cell Precursor ◽  
Leukemia Cell Lines

scholarly journals Low molecular weight B cell growth factor induces proliferation of human B cell precursor acute lymphoblastic leukemias

Blood ◽  
1987 ◽  
Vol 70 (1) ◽  
pp. 132-138 ◽  
Author(s):  
B Wormann ◽  
SR Mehta ◽  
AL Maizel ◽  
TW LeBien
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Growth Factor ◽  
Cell Growth ◽  
B Cell ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cells ◽  
Cell Precursor ◽  
B Cell Growth Factor ◽  
B Cell Precursors

Experiments were conducted to determine the effect of low mol wt B cell growth factor (L-BCGF) on B cell precursor acute lymphoblastic leukemia (ALL). L-BCGF induced a significant increase in 3H-TdR incorporation in 28 of 37 bone marrow aspirates from patients with B cell precursor ALL, with stimulation indices ranging from 2 to 129. Fluorescence-activated cell sorting confirmed that in five of seven patients the common acute lymphoblastic leukemia antigen (CALLA)/CD10 positive leukemic cells were responding directly to L-BCGF. L-BCGF was capable of inducing, in some patients, an increase in absolute viable cells and could also induce colony formation in vitro. The response of B cell precursor ALL was not attributable to beta IL 1, IL 2, or gamma interferon. These results indicate that the majority of B cell precursor ALL undergo a proliferative response to L-BCGF, suggesting a regulatory role for this lymphokine in the growth of B cell precursors.

High prevalence of MEF2D fusion in human B‐cell precursor acute lymphoblastic leukemia cell lines

2020 ◽  
Vol 38 (4) ◽  
pp. 614-617
Author(s):  
Koshi Akahane ◽  
Takahiko Yasuda ◽  
Shinobu Tsuzuki ◽  
Fumihiko Hayakawa ◽  
Nobutaka Kiyokawa ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
B Cell ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cell ◽  
Cell Precursor ◽  
Leukemia Cell Lines ◽  
High Prevalence ◽  
Human B Cell

scholarly journals Different molecular consequences of the 1;19 chromosomal translocation in childhood B-cell precursor acute lymphoblastic leukemia

Blood ◽  
1992 ◽  
Vol 79 (7) ◽  
pp. 1781-1788
Author(s):  
E Privitera ◽  
MP Kamps ◽  
Y Hayashi ◽  
T Inaba ◽  
LH Shapiro ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
B Cell ◽  
Cytogenetic Analysis ◽  
Lymphoblastic Leukemia ◽  
Chromosomal Translocation ◽  
Leukemic Cell ◽  
Molecular Techniques ◽  
Leukemic Cells ◽  
Cell Precursor ◽  
Chimeric Transcripts

The prognostically important 1;19 chromosomal translocation can alter the E2A gene on chromosome 19p13 in childhood B-cell precursor acute lymphoblastic leukemia (ALL), leading to formation of a fusion gene (E2A-PBX1) that encodes a hybrid transcription factor with oncogenic potential. It is not known whether this molecular alteration is a uniform consequence of the t(1;19) or is restricted to translocation events within specific immunologic subtypes of the disease. Therefore, we studied leukemic cells from 25 cases of B-cell precursor ALL, with or without evidence of cytoplasmic Ig mu heavy chains (cIg); 17 cases had the t(1;19) by cytogenetic analysis. Leukemic cell DNA samples were analyzed by Southern blotting to detect alterations within the E2A genomic locus; a polymerase chain reaction assay was used to identify expression of chimeric E2A-pbx1 transcripts in leukemic cell RNA; and immunoblotting with anti-Pbx1 antibodies was used to detect hybrid E2A- Pbx1 proteins. Of 11 cases of cIg+ ALL with the t(1;19), 10 had E2A- pbx1 chimeric transcripts with identical junctions and a characteristic set of E2A-Pbx1 hybrid proteins. Each of these cases had E2A gene rearrangements, including the one in which fusion transcripts were not detected. By contrast, none of the six cases of t(1;19)-positive, cIg- ALL had evidence of rearranged E2A genomic restriction fragments, detectable E2A-pbx1 chimeric transcripts, or hybrid E2A-Pbx1 proteins. Typical chimeric E2A-pbx1 transcripts and proteins were detected in one of eight cIg+ leukemias in which the t(1;19) was not identified by cytogenetic analysis, emphasizing the increased sensitivity of molecular analysis for detection of this abnormality. We conclude that the molecular breakpoints in cases of cIg- B-cell precursor ALL with the t(1;19) differ from those in cIg+ cases with this translocation. Leukemias that express hybrid oncoproteins such as E2A-Pbx1 or Bcr-Abl have had a poor prognosis in most studies. Thus, molecular techniques to detect fusion genes and their aberrant products should allow more timely and appropriate treatment of these aggressive subtypes of the disease.

scholarly journals JAK2 Aberrations in Childhood B-Cell Precursor Acute Lymphoblastic Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 583-583
Author(s):  
Elisabeth M.P. Steeghs ◽  
Isabel S. Jerchel ◽  
Willemieke de Goffau-Nobel ◽  
Alex Q. Hoogkamer ◽  
Judith M. Boer ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
B Cell ◽  
Induced Resistance ◽  
Conflicts Of Interest ◽  
Ex Vivo ◽  
Lymphoblastic Leukemia ◽  
Annexin V ◽  
Leukemic Cell ◽  
Leukemic Cells ◽  
Cell Precursor

Abstract Background In high risk pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) patients, gain of function mutations and translocations affecting JAK2 have been described. These mutations and translocations result in aberrant kinase signaling and may therefore serve as an ideal target for precision medicines. Aim Evaluate the frequency and prognosis of JAK2 lesions among different subtypes of childhood BCP-ALL, and study the efficacy of the JAK1/2 inhibitors momelotinib and ruxolitinib. Methods This study comprised 77 BCR-ABL1-like cases and 76 B-other cases which were screened for JAK2 translocations using RT-PCR. Furthermore a representative pediatric cohort of 461 newly diagnosed BCP-ALL cases was screened for JAK2 mutations using targeted next-generation sequencing. Clinical analyses were performed in 341 BCP-ALL patients. Patient-derived-xenograft (PDX) cells were isolated from NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice, which were injected with primary leukemic cells. Purity of PDX cells was enriched to over 90% and presence or absence of JAK2 lesions was validated. PDX and primary leukemic cells were exposed to a dilution series of momelotinib or ruxolitinib for four days. Where indicated, cells were pre-incubated with 25 ng/ml TSLP for 1 hour. In mono-culture assays, cytotoxicity was quantified using MTT and in co-culture assays flow cytometry was used. Leukemic cells were discriminated from mesenchymal stromal cells (MSCs) using CD19 and viability was assessed by Annexin V and Propidium Iodide. Western blotting was used to study protein expression levels. Results JAK2 translocations were detected in 6.5% of BCR-ABL1-like cases (3 PAX5-JAK2 cases, 1 TERF2-JAK2 case and 1 BCR-JAK2 case), but not in B-other cases. JAK2 mutations were identified in 3.5% of all BCP-ALL cases, which included JAK2 mutations in BCR-ABL1-like (7.6%), B-other (11.9%), and high hyperdiploid cases (1.6%), but not in MLL rearranged, BCR-ABL1-positive, ETV6-RUNX1-positive or TCF3-PBX1-positive cases. Cumulative incidence of relapse in patients harboring JAK2 lesions was as poor as in JAK2 wildtype BCR-ABL1-like and B-other patients. Efficacy of the JAK1/2 inhibitors momelotinib and ruxolitinib was examined in JAK2 lesion positive (primary and PDX) leukemic cells. Inhibitors were cytotoxic in both translocated and mutated cells, although efficacy in JAK2 mutated cells highly depended on CRLF2 activation by TSLP. CRLF2 activation resulted in downstream STAT5 activation and sensitization towards ruxolitinib compared to unstimulated cells (p < 0.05). Cells harboring JAK2 translocations signaled independently of CRLF2. Although momelotinib and ruxolitinib exposure blocked downstream STAT1/5 phosphorylation, both inhibitors also induced accumulation of phosphorylated JAK2Y1007. Consequently, release of the inhibitors resulted in a profound re-activation of JAK2 signaling, observed by upregulation of downstream STAT1/5 signaling. Furthermore, we observed microenvironment-induced resistance. Culturing leukemic cells in the presence of primary bone marrow MSCs induced resistance to ruxolitinib, compared to leukemic cells in single cultures (p < 0.05). A similar trend was observed for momelotinib. In addition, patients harboring JAK2 mutations displayed a heterogeneous leukemic cell population. Mouse xenograft models revealed different outgrowth patterns of leukemic cells, in which the JAK2 mutated clone persisted, decreased or even disappeared, resulting in outgrowth of JAK2 wildtype leukemic cells. Moreover, JAK2 mutations were not mutually exclusive for other pathway mutations (e.g. KRAS). Conclusion JAK2 translocations and mutations were detected in poor prognostic BCP-ALL cases. In ex vivo assays, the JAK1/2 inhibitors momelotinib and ruxolitinib were cytotoxic in JAK2 aberrant cells. Despite these promising findings, we identified certain limitations of these inhibitors. Inhibitors induced accumulation of phosphorylated JAK2Y1007, which resulted in a profound re-activation of JAK2 signaling upon their release. Furthermore, our data suggest that the effect of JAK inhibition may be compromised by mutations in alternative survival pathways and by microenvironment-induced resistance. Taken together, our data yield important directives for the clinical use of JAK inhibitors in pediatric BCP-ALL. Disclosures No relevant conflicts of interest to declare.

scholarly journals Expression of common acute lymphoblastic leukemia antigen (CALLA) by lymphomas of B-cell and T-cell lineage

Blood ◽  
1981 ◽  
Vol 58 (3) ◽  
pp. 648-652 ◽  
Author(s):  
J Ritz ◽  
LM Nadler ◽  
AK Bhan ◽  
J Notis-McConarty ◽  
JM Pesando ◽  
...  
Keyword(s):  
Lymph Node ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
B Cell ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Lymphoid Cells ◽  
Leukemic Cells ◽  
Hodgkin's Lymphomas ◽  
Leukemia Antigen

Previous studies have demonstrated that the common acute lymphoblastic leukemia antigen (CALLA) is expressed by leukemic cells from approximately 80% of patients with non-T-cell ALL and 30%-50% of patients with chronic myelocytic leukemia in blast crisis. A small number of normal bone marrow and fetal liver cells also express CALLA, but the functional role of this molecule is unknown. In the present study, we have used a monoclonal antibody (J5) specific for CALLA to study the expression of this antigen in non-Hodgkin's lymphomas. Within the B-cell lymphomas, it was found the CALLA was expressed by almost all Burkitt's and nodular poorly differentiated lymphocytic lymphomas. Within the T-cell lymphomas, CALLA was expressed in 40% of patients with lymphoblastic lymphoma. Three of 3 Burkitt's lymphoma cell lines and three of eight T-lymphoblast cell lines were also found to express CALLA. Normal spleen, lymph node, and thymus cells were not reactive with J5 antibody. These findings indicate that expression of CALLA is not limited to relatively undifferentiated leukemic lymphoblasts but also occurs in more differentiated lymphoid malignancies. However, normal differentiated lymphoid cells in lymph node, spleen, and thymus, which have a phenotype similar to that of lymphoma cells, do not appear to express CALLA.

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