Tyrosine Kinase Inhibitor STI571 (Imatinib) Cooperates with Wild-Type p53 on K562 Cell Line to Enhance Its Proapoptotic Effects

2005 ◽  
Vol 114 (3) ◽  
pp. 150-154 ◽  
Author(s):  
Gianluca Brusa ◽  
Manuela Mancini ◽  
Fabio Campanini ◽  
Alberto Calabrò ◽  
Elisa Zuffa ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitor ◽  
Cell Line ◽  
K562 Cell ◽  
Kinase Inhibitor ◽  
Wild Type ◽  
K562 Cell Line ◽  
Wild Type P53

Effects of AMN107, a Novel Aminopyrimidine Tyrosine Kinase Inhibitor, on Human Mast Cells Bearing Wild-Type or Mutated Codon 816 c-kit.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3528-3528 ◽  
Author(s):  
Srdan Verstovsek ◽  
Cem Akin ◽  
Giles J. Francis ◽  
Manshouri Taghi ◽  
Ly Huynh ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitor ◽  
Cell Line ◽  
Cell Lines ◽  
Cellular Proliferation ◽  
Kinase Inhibitor ◽  
Wild Type ◽  
Kit Mutation

Abstract Background. Majority of adult patients with systemic mastocytosis (SM) have activating mutation in codon 816 of c-kit (CD117), a receptor on the surface of mast cells. This abnormality is responsible for the pathogenesis of the disease. Methods. We investigated the effects of a newly designed tyrosine kinase inhibitor, AMN107, by comparing its in vitro inhibitory potency on c-kit mutated mast cell lines and patient samples with that of imatinib mesylate, another tyrosine kinase inhibitor, effective in some patients with SM. Two cell lines, subclones of HMC-1 cells, were used: HMC-1560 carrying juxtamembrane domain mutation in codon 560 of c-kit, and HMC-1560, 816 carrying both codon 560 mutation and tyrosine kinase domain mutation in codon 816 of c-kit. Results. In HMC-1560 mast cell line carrying wild-type codon 816, AMN107 was as potent as imatinib in inhibiting cellular proliferation, with IC50 values of 108 and 74 nM respectively, while in HMC-1560, 816 cell line carrying 816 mutation, neither medication had an effect. AMN107 was also as effective as imatinib in inhibiting phosphorylation of c-kit tyrosine kinase in HMC-1560 cells. The inhibition of cellular proliferation was associated with induction of apoptosis in HMC-1560 cells. AMN107 in concentrations up to 1 uM had no effect on bone marrow mast cells carrying D816V c-kit mutation obtained from patients with mastocytosis. Conclusions. Our results suggest similar potency of AMN107 and imatinib in mast cells that carry wild-type codon 816, but no activity against codon 816 mutation carrying cells.

Effects of AMN107, a novel aminopyrimidine tyrosine kinase inhibitor, on human mast cells bearing wild-type or mutated codon 816 c-kit

2006 ◽  
Vol 30 (11) ◽  
pp. 1365-1370 ◽  
Author(s):  
Srdan Verstovsek ◽  
Cem Akin ◽  
Taghi Manshouri ◽  
Alfonso Quintás-Cardama ◽  
Ly Huynh ◽  
...  
Keyword(s):  
Mast Cells ◽  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitor ◽  
Kinase Inhibitor ◽  
Wild Type ◽  
Human Mast Cells

The Effect of Imatinib Mesylate on the Signal Transduction Cascade Leading to down Regulation of Telomerase Activity in K562 Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4787-4787
Author(s):  
Rahav Mor ◽  
Orit Uziel ◽  
Ofer Shpilberg ◽  
Judith Lahav ◽  
Pia Raanani ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Tyrosine Kinase ◽  
Cell Line ◽  
Imatinib Mesylate ◽  
K562 Cell ◽  
K562 Cells ◽  
Telomerase Activity ◽  
K562 Cell Line ◽  
Signal Transduction Cascade ◽  
Cellular Components

Abstract Imatinib mesylate (IM) is a tyrosine kinase inhibitor selective for Bcr-Abl, c-Kit, and platelet-derived growth factor receptor kinases. IM inhibits kinase activity through competition for ATP binding. IM is indicated for the treatment of newly diagnosed patients with Philadelphia chromosome positive (BCR-ABL positive) chronic myeloid leukemia (CML) in chronic phase. Recent publications demonstrate that this drug may also target other cellular components. In light of the important role of telomerase in malignant transformation, we evaluated the effect of IM on the signal transduction cascade leading to modulation of telomerase activity in the BCR-ABL positive K562 cell-line. In addition, we studied the effect of IM on telomerase in an IM resistant K562 cell-line (K562res). The K562res cell-line is resistant to the effect of IM on the BCR-ABL protein. However, the effect of IM on telomerase in these cells is unknown. Therefore, using these cells will enable us to study the connection between the signal transduction cascade of BCR-ABL and that of telomerase. IM caused an 80% inhibition of telomerase activity in both K562 and K562res cell-lines. Inhibition of telomerase activity was associated with 50% inhibition of proliferation. Inhibition of telomerase activity was not caused by changes in the transcription level of hTERT (the catalytic subunit of the enzyme). On the other hand, it seemed mainly to be caused by post-translational modifications only in K562 cells namely, a 2-fold dephosphorylation of AKT, known to phosphorylate telomerase. In addition, IM was found to upregulate the expression of PTEN (known to negatively regulate AKT) again only in K562 cells. IM did not affect the levels of phosphorylaetd AKT or PTEN in K562res cells. However, IM caused an approximate 2-fold upregulation of p53 (a transcription factor of PTEN) levels both in K562 and K562res cells. Our results demonstrate the ability of IM to inhibit telomerase activity in BCR-ABL expressing cell lines. Telomerase activity inhibition was demonstrated in K562 cells as well as in K562 cells resistant to high concentrations of IM. Therefore, the inhibitory effect of IM on telomerase activity isn’t necessarily mediated through the known tyrosine kinase targets of IM. The effect of IM on the signal transduction cascade leading to the down-regulation of telomerase activity seems to be different in K562 cells and K562res cells. While the signal transduction cascade in K562 cells appears to go through AKT and PTEN, the response to IM in K562res cells seems to be mediated by other yet unknown pathways. Future work is needed in order to clarify possible mechanism(s) by which IM down-regulates telomerase activity in these cells. This study supports previous studies demonstrating telomerase activity as an additional cellular target of IM. In addition, this study shows that cells known to be resistant to IM with regards to its effect on BCR-ABL could still be sensitive to IM treatment regarding other cellular components.

Efficacy of Ponatinib Against ABL Tyrosine Kinase Inhibitor Resistant Leukemia Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4413-4413
Author(s):  
Seiichi Okabe ◽  
Tetsuzo Tauchi ◽  
Kazuma Ohyashiki
Keyword(s):  
Cell Proliferation ◽  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitor ◽  
Cell Line ◽  
Cell Lines ◽  
Kinase Inhibitor ◽  
Resistant Cell ◽  
Point Mutant ◽  
Abl Tyrosine Kinase ◽  
Abl Tyrosine Kinase Inhibitor

Abstract Abstract 4413 Dasatinib (Sprycel®) and nilotinib (Tasigna®) have each shown superior efficacy as front line treatment for patients with chronic myeloid leukemia (CML)-chronic phase (CP) in comparison with imatinib. Dasatinib and nilotinib are also used for the treatment of CML patients resistant or intolerant to imatinib therapy. However, a substantial number of patients are acquired resistance to nilotinib or dasatinib, the management of CML following the development of ABL tyrosine kinase inhibitor (TKI) resistance remains a challenge. Ponatinib, also known as AP24534, is an oral, the multi-targeted TKI. Ponatinib is currently being investigated in a pivotal phase 2 clinical trial (PACE trial) in patients with resistant or intolerant CML and Philadelphia positive acute lymphoblastic leukemia (Ph+ ALL). However, the molecular and functional consequences of ponatinib against ABL TKI resistant cells are not fully known. In this study, we investigated the ponatinib efficacy by using the BCR-ABL positive cell line, K562 and ABL TKI resistant (K562 imatinib resistant (K562IR), K562 nilotinib resistant (K562NR), K562 dasatinib resistant (K562DR) cells and murine Ba/F3 cell line which was transfected BCR-ABL random mutation, and established the new imatinib and nilotinib resistant Ba/F3 BCR-ABL point mutant (E334V) cells. We first examined the cell proliferation by using resistant cell lines. The proliferation of K562IR and K562 NR and K562DR did not decrease after imatinib (10 μM) or nilotinib (2 μM) or dasatinib (1 μM) treatment compared with parental cell line, K562. The BCR-ABL kinase domain mutation was not found. Point mutant Ba/F3 cell (E334V) was also highly resistant to imatinib (IC50: 15μM) and nilotinib (IC50: 7.5μM). We next examined the intracellular signaling by using these cell lines. Phosphorylation of BCR-ABL and Crk-L was not decreased by ABL TKIs in K562IR, K562NR and Ba/F3 BCR-ABL point mutant cells (E334V). We found the one of src family kinase, Lyn was activated in K562IR and K562NR cells. Co-treatment src kinase inhibitor, PP2 and imatinib or nilotinib significantly reduced the cell proliferation of K562IR and K562NR cells. We also found the phosphorylation of Lyn was reduced and poly (ADP-ribose) polymerase (PARP) was activated. We next examined the efficacy of ponatinib against imatinib and nilotinib resistant cell lines. 72 hours treatment of ponatinib exhibits cell growth inhibition against K562 (IC50: 0.02nM), K562IR (IC50: 15nM), and K562NR (IC50: 3.5nM) cells. We also found the phosphorylation of BCR-ABL, Lyn and Crk-L was reduced and PARP was activated after ponatinib treatment. We next examined the imatinib and nilotinib resistant Ba/F3 cells with point mutant (E334V). We found the cell proliferation was significantly decreased after ponatinib treatment (IC50: 3nM). We also found the phosphorylation of BCR-ABL, Crk-L was reduced and PARP was activated after ponatinib treatment. We next investigated the ponatinib activity against dasatinib resistant cells. We found K562DR cells were highly resistant to ponatinib. IC50 was 400nM. These results suggest that the expression and protein activation signatures identified in this study provide insight into the mechanism of resistance to ABL TKIs. We also demonstrate ponatinib has anti-leukemia effect by reducing ABL and Lyn kinase activity and development of ponatinib resistance and suggests that this information may be of therapeutic relevance. Disclosures: No relevant conflicts of interest to declare.

Effects of tyrosine kinase inhibitor STI571 on human mast cells bearing wild-type or mutated c-kit

2003 ◽  
Vol 31 (8) ◽  
pp. 686-692 ◽  
Author(s):  
Cem Akin ◽  
Knut Brockow ◽  
Claudio D'Ambrosio ◽  
Arnold S Kirshenbaum ◽  
Yongsheng Ma ◽  
...  
Keyword(s):  
Mast Cells ◽  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitor ◽  
Kinase Inhibitor ◽  
Wild Type ◽  
Human Mast Cells
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