Ectopic Expression of Mer Receptor Tyrosine Kinase in Childhood T Cell Acute Lymphoblastic Leukemia.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4310-4310
Author(s):  
Dana B. Salzberg ◽  
Amy K. Keating ◽  
Jian-zhe Cao ◽  
Susan Sather ◽  
Kimberley Hill ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Tyrosine Kinase ◽  
Cell Lines ◽  
Receptor Tyrosine Kinase ◽  
Lymphoblastic Leukemia ◽  
Ectopic Expression ◽  
Surface Expression ◽  
Protein Surface ◽  
Sample Number

Abstract Tyrosine kinases play an important role in normal cellular growth and differentiation. Deregulation of tyrosine kinase activity can result in cellular transformation leading to the development of human cancer. The Mer receptor tyrosine kinase, initially cloned from a human B lymphoblastoid cell line, is expressed in a spectrum of hematopoetic, epithelial, and mesenchymal cell lines. Interestingly, while the RNA transcript of Mer is detected in numerous T and B lymphoblastic cell lines, Mer RNA is not found in normal human thymocytes, lymphocytes or in PMA/PHA stimulated lymphocytes. We have developed an anti-human Mer monoclonal antibody to further study the ectopic Mer expression in lymphoblasts. The antibody detects several forms of the Mer protein including a fully glycosylated 205 kD Mer protein in monocytes and a less glycosylated 170–180 kD Mer protein in acute lymphoblastic leukemia (ALL) cell lines. We analyzed lymphoblasts from 16 T cell ALL patients diagnosed between July 1995 and July 2004 at The Children’s Hospital, Denver for Mer protein surface expression. Of the T cell ALL patient samples, we found that 9/16 (56%) were positive for Mer protein surface expression. Although we were not able to statistically evaluate the clinical outcomes relative to Mer expression due to the study sample number, there was a statistically significant association between positive expression of Mer and lack of surface expression of CD3 (p = 0.035). We found that 7/9 (78%) of the Mer positive lymphoblasts lacked CD3 surface expression, while only 1/6 (17%) of the Mer negative samples lacked CD3 surface expression (see figure). Lymphoblasts that lack surface expression of CD3 represent an immature phenotype and have been associated with a decreased event free survival as compared with surface positive CD3 lymphoblasts. Further investigation of the ectopic expression of Mer in lymphoblasts may reveal the use of this novel Mer glycosylated protein as a prognostic marker and possibly a future therapeutic target in the treatment of childhood leukemia. Figure Figure

scholarly journals The receptor tyrosine kinase p185HER2 is expressed on a subset of B- lymphoid blasts from patients with acute lymphoblastic leukemia and chronic myelogenous leukemia

Blood ◽  
1995 ◽  
Vol 86 (5) ◽  
pp. 1916-1923 ◽  
Author(s):  
HJ Buhring ◽  
I Sures ◽  
B Jallal ◽  
FU Weiss ◽  
FW Busch ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Tyrosine Kinase ◽  
Cell Lines ◽  
Receptor Tyrosine Kinase ◽  
Lymphoblastic Leukemia ◽  
Blast Crisis ◽  
Hematopoietic Cell ◽  
Myelogenous Leukemia ◽  
Leukemic Cells ◽  
B Lymphoid

The class I receptor tyrosine kinase (RTK) HER2 is an oncoprotein that is frequently involved in the pathogenesis of tumors of epithelial origin. Here we report mRNA expression in peripheral blood and bone marrow cells from healthy donors in hematopoietic cell lines and leukemic blasts from patients with acute lymphoblastic leukemia (ALL), acute myeloblastic leukemia (AML), chronic lymphoblastic leukemia (CLL), and chronic myeloid leukemia (CML). However, cell surface expression of HER2 protein (p185HER2) was found exclusively on a subset of leukemic cells of the B-lymphoblastic lineage. p185HER2 expression was found on blasts in 2 of 15 samples from infants, 9 of 19 samples from adult patients with C-ALL (CD19+CD10+), and 1 of 2 samples from patients with pro-B ALL (CD19+CD10-), whereas none of the leukemic cells from patients with AML (0/30), T-ALL (0/7), CLL (0/5) (CD19+CD5+), or CML in chronic and accelerated phase (0/5) or in blast crisis with myeloid differentiation (0/14) were positive for p185HER2. However, cells from 3 of 4 patients with CML in B-lymphoid blast crisis (CD19+CD10+) expressed high levels of p185HER2, which was also found on the surface of the CML-derived B-cell lines BV-173 and Nalm-1. Our study shows p185HER2 expression on malignant cells of hematopoietic origin for the first time. Aberrant expression of this oncogenic receptor tyrosine kinase in hematopoietic cell types may be an oncogenic event contributing to the development of a subset of B- lymphoblastic leukemias.

Pathway Dependence on the Tyrosine Kinase TYK2 and Its Mediator STAT1 In T-Cell Acute Lymphoblastic Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3155-3155
Author(s):  
Takaomi Sanda ◽  
Jeffrey W Tyner ◽  
Alejandro Gutierrez ◽  
Vu N Ngo ◽  
Richard Moriggl ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Tyrosine Kinase ◽  
Cell Lines ◽  
Small Molecule ◽  
Lymphoblastic Leukemia ◽  
B Cell Lymphoma ◽  
Knock Down ◽  
A Genome ◽  
Cell Acute Lymphoblastic Leukemia

Abstract Abstract 3155 The often aggressive and unpredictable behavior of T-cell lymphoblastic malignancies continues to pose both major clinical challenges in children and adults. To discover oncogenic pathways downstream of critical genetic abnormalities that are characteristically deregulated in T-cell acute lymphoblastic leukemia (T-ALL), and to identify novel molecular targets for anti-leukemic agents with T-cell specificity, we carried out a genome-wide functional screen in T-ALL cell lines using a retroviral library of inducible short-hairpin RNAs (shRNAs). Among the genes that are required for the growth of T-ALL cells, we found that loss of TYK2, a JAK family tyrosine kinase, was specifically lethal in each of three T-ALL cell lines that we tested in this screen. By contrast, TYK2 knock-down did not affect the growth of cell lines from diffuse large B-cell lymphoma or multiple myeloma, indicating that TYK2 is specifically required for the growth of T-ALL cells. We confirmed by knock-down with multiple independent shRNAs that the loss of TYK2 induces apoptosis in T-ALL, whereas knock-down of other JAK proteins (JAK1, JAK2 or JAK3) had no effect. We found that the TYK2 protein is constitutively phosphorylated in many T-ALL cell lines, and that these cells are sensitive to small molecule JAK/TYK2 inhibitors, including JAK inhibitor-I, AG-490 and CEP-701. To identify upstream receptors involved in TYK2 activation, we knocked down IFNAR, IFNGR, IL10R and IL12RB, and found that loss of IFNAR1 and IFNAR2 specifically inhibit the growth of T-ALL cells, as strongly as TYK2 knock-down. In addition, targeted knock-down analysis of downstream STAT proteins revealed that loss of STAT1 also inhibits the growth of T-ALL cells, indicating that this transcription factor is involved in the TYK2 pathway and required for cell survival. In fact, STAT1 protein was constitutively phosphorylated in many T-ALL cell lines and this phosphorylation was inhibited by both TYK2 knock-down and treatment with JAK/TYK2 inhibitors. Although interferon-mediated pathways are cytostatic in many cell types, our results indicate a requirement for the IFNAR-TYK2-STAT1 pathway in promoting the growth and survival of T-ALL cells. Dependence on this pathway confers unique sensitivity of T-ALL cells to TYK2 inhibition by small molecule inhibitors, thus providing a novel therapeutic target for clinical testing in patients with this disease. Disclosures: Druker: Molecular MD: Equity Ownership.

Anti-Leukemic Activity of the TYK2 Selective Inhibitor Ndi-031301 in T-Cell Acute Lymphoblastic Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1596-1596
Author(s):  
Koshi Akahane ◽  
Zhaodong Li ◽  
Julia Etchin ◽  
Alla Berezovskaya ◽  
Evisa Gjini ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Tyrosine Kinase ◽  
P38 Mapk ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Parp Cleavage ◽  
Immunodeficient Mice ◽  
Tyrosine Kinase 2 ◽  
Cell Acute Lymphoblastic Leukemia

Abstract T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy resulting from the transformation of T-cell progenitors. Although the prognosis of this disease has substantially improved due to the introduction of intensified chemotherapy, the clinical outcome of T-ALL patients with primary resistant or relapsed disease remains poor, indicating that further therapeutic improvement is urgently needed. We have previously demonstrated that activation of tyrosine kinase 2 (TYK2) contributes to aberrant survival of human T-ALL cells. TYK2 is a member of the Janus-activated kinase (JAK) tyrosine kinase family and our report was the first to implicate TYK2 in T-ALL pathogenesis. Indeed, our gene knockdown experiments showed TYK2 dependency in 14 of 16 (88%) T-ALL cell lines and 5 of 8 (63%) patient-derived T-ALL cells tested, suggesting that inhibition of TYK2 would be beneficial in most patients with T-ALL. Based on these findings, we investigated the therapeutic potential of a novel small-molecule TYK2 kinase inhibitor NDI-031301 in T-ALL. We found that NDI-031301 shows potent and selective inhibitory activity against TYK2 in a cellular context, because this compound strongly inhibited the growth of TYK2-transfomed Ba/F3 cells when compared to the JAK inhibitors tofacitinib and baricitinib, whereas Ba/F3 cells transformed by other tyrosine kinases showed decreased sensitivity to NDI-031301. NDI-031301 induced robust growth inhibition in each of 4 human T-ALL cell lines representing different molecular subtypes of the disease (DU.528, KOPT-K1, HPB-ALL and SKW-3), with IC50 values of 0.8186 - 2.380 μM after 72 hours of exposure. NDI-031301 treatment of human T-ALL cell lines resulted in induction of apoptosis that was not observed with tofacitinib and baricitinib. To elucidate the mechanism of apoptosis induced by NDI-031301 in T-ALL cells, we next investigated cellular signaling pathways that are associated with cell survival and specifically affected by TYK2 inhibition with NDI-031301. Western blotting analysis demonstrated that treatment with 3 μM of NDI-031301 resulted in reduction of STAT1 Tyr-701 phosphorylation and BCL2 levels in KOPT-K1 cells, consistent with our previous finding that TYK2 phosphorylates STAT1 and upregulates BCL2 expression in most T-ALL cells. Surprisingly, the treatment also uniquely led to activation of three mitogen-activated protein kinases (MAPKs), resulting in phosphorylation of ERK, SAPK/JNK and p38 MAPK coincident with PARP cleavage, which was not observed with tofacitinib and baricitinib. NDI-031301-mediated activation of SAPK/JNK and p38 MAPK pathways are likely mediated through inhibition of TYK2, because increased phosphorylation levels of SAPK/JNK and p38 MAPK were observed in the cells transfected with TYK2-targeting shRNAs, while the levels of ERK1/2 phosphorylation were not upregulated. Further investigation revealed that activation of p38 MAPK occurred within 1 hour of NDI-031301 treatment and was responsible for NDI-031301-induced T-ALL cell death, as pharmacologic inhibition of p38 MAPK by SB203580 partially rescued apoptosis induced by TYK2 inhibitor, while inhibition of ERK or SAPK/JNK showed no rescue effects. Finally, we found that daily oral administration of NDI-031301 at 100mg/kg BID to immunodeficient mice engrafted with KOPT-K1 T-ALL cells was well tolerated, and led to decreased tumor burden and a significant survival benefit. After 29 days of treatment, the mice receiving NDI-031301 had marked reductions in infiltration of leukemia cells into spleen and bone marrow by comparison with controls. Thus, our findings clearly support TYK2 inhibition with NDI-031301 or a related compound as a potential therapeutic strategy for patients with T-ALL, and also raise the possibility that enhancing p38 MAPK activation in T-ALL cells may be an approach to accentuate its anti-leukemic activity. Disclosures Masse: Nimbus Therapeutics: Employment. Miao:Nimbus Therapeutics: Employment. Rocnik:Nimbus Therapeutics: Employment. Kapeller:Nimbus Therapeutics: Employment.

Transcriptional Regulation of Oncogenic MEF2C In T-Cell Acute Lymphoblastic Leukemia (T-ALL).

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3636-3636
Author(s):  
Stefan Nagel ◽  
Letizia Venturini ◽  
Corinna Meyer ◽  
Maren Kaufmann ◽  
Michaela Scherr ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Cell Lines ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Ectopic Expression ◽  
Regulatory Elements ◽  
Hematopoietic Stem ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Bhlh Proteins

Abstract Abstract 3636 Myocyte enhancer factor 2C (MEF2C) is a transcription factor of the MADS-box family which is physiologically expressed in hematopoietic stem cells and during development of B-cells. Recently, we identified ectopic expression of MEF2C in T-cell acute lymphoblastic leukemia (T-ALL) cell lines activated either via chromosomally mediated ectopic expression of homeodomain protein NKX2-5 or via deletion of non-coding exon and promoter regions at 5q14, suggesting loss of negative regulatory elements. Our aim was to identify additional transcriptional regulators of MEF2C in T-ALL. Therefore, we analyzed the sequence of the MEF2C 5′-region, thus identifying potential regulatory binding sites for GFI1B, basic helix-loop-helix (bHLH) proteins, STAT5 and HOXA9/HOXA10. Overexpression studies demonstrated MEF2C activation by GFI1B (strong), LYL1 and TAL1 leukemic bHLH proteins (weak), and inhibition by STAT5 (strong) and HOXA9/HOXA10 (weak). Chromatin-Immuno-Precipitation analysis demonstrated direct binding of GFI1B, LYL1 and STAT5 but not of HOXA10 to the MEF2C 5′-region in T-ALL cells. However, HOXA9/HOXA10 activated expression of NMYC which in turn mediated MEF2C repression, indicating an indirect mode of MEF2C regulation. Chromosomal deletion of the 5′-MEF2C STAT5 binding site in LOUCY cells by del(5)(q14), reduced expression levels of STAT5 protein in some MEF2C-positve T-ALL cell lines, and the presence of inhibitory IL7-JAK-STAT5-signaling highlighted the repressive impact of this factor in MEF2C regulation. Taken together, our results indicate that ectopic expression of MEF2C in T-ALL cells is mainly regulated via activating leukemic transcription factors GFI1B or NKX2-5 and by escaping inhibitory STAT5-signaling. Disclosures: No relevant conflicts of interest to declare.

Abstract 2809: Pathway dependence on the tyrosine kinase TYK2 in T-cell acute lymphoblastic leukemia

2011 ◽  
Author(s):  
Takaomi Sanda ◽  
Jeffrey W. Tyner ◽  
Alejandro Gutierrez ◽  
Vu N. Ngo ◽  
Richard Moriggl ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Tyrosine Kinase ◽  
Lymphoblastic Leukemia ◽  
Cell Acute Lymphoblastic Leukemia

scholarly journals Does activation of the TAL1 gene occur in a majority of patients with T- cell acute lymphoblastic leukemia? A pediatric oncology group study

Blood ◽  
1995 ◽  
Vol 86 (2) ◽  
pp. 666-676 ◽  
Author(s):  
RO Bash ◽  
S Hall ◽  
CF Timmons ◽  
WM Crist ◽  
M Amylon ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Lymphoblastic Leukemia ◽  
Ectopic Expression ◽  
Leukemic Cells ◽  
Monoallelic Expression ◽  
Regulatory Sequences ◽  
Cis Acting ◽  
Polymorphic Dinucleotide ◽  
Cell Acute Lymphoblastic Leukemia

Almost 25% of patients with T-cell acute lymphoblastic leukemia (T-ALL) have tumor-specific rearrangements of the TAL1 gene. Although TAL1 expression has not been observed in normal lymphocytes, TAL1 gene products are readily detected in leukemic cells that harbor a rearranged TAL1 allele. Hence, it has been proposed that ectopic expression of TAL1 promotes the development of T-ALL. In this report, we show that TAL1 is expressed in the leukemic cells of most patients with T-ALL, including many that do not display an apparent TAL1 gene alteration. A polymorphic dinucleotide repeat in the transcribed sequences of TAL1 was used to determine the allele specificity of TAL1 transcription in primary T-ALL cells. Monoallelic expression of TAL1 was observed in the leukemic cells of all patients (8 of 8) bearing a TAL1 gene rearrangement. In the leukemic cells of patients without detectable TAL1 rearrangements, TAL1 transcription occurred in either a monoallelic (3 of 7 patients) or a biallelic (4 of 7 patients) fashion. Thus, TAL1 activation in these patients may result from subtle alterations in cis-acting regulatory sequences (affecting expression of a single TAL1 allele) or changes in trans-acting factors that control TAL1 transcription (affecting expression of both TAL1 alleles).

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