In vivo inhibition of Bruton Tyrosine Kinase (BTK) protects against alcoholic liver disease

Abstract The Bruton tyrosine kinase (BTK) inhibitor, ibrutinib has produced durable remissions in chronic lymphocytic leukemia (CLL). We describe a CLL patient who progressed while receiving ibrutinib following 20 months of once daily dosing. A cysteine-to-serine amino acid replacement was identified in BTK at position 481 that disrupts the covalent, but not non-covalent, binding of ibrutinib to BTK in silico structural modeling1. The mutation was present in relapsed samples while absent in the pre-treatment and responding samples. Following the mutation, the B cell receptor (BCR) pathway was reactivated as evidenced by increased cell signaling activities and gene expression profiles. Comparing the relapsed samples with the pre-treatment and responding samples, at the cellular level, mutated CLL cells displayed higher levels of the cell proliferation marker Ki67 in vivo and higher levels of ex-vivo BrdU incorporation. Transfection of the C481S mutant construct into a sensitive lymphoma cell line rendered it much more resistant to ibrutinib treatment demonstrating the cellular impact of the mutation (see attached graph). Interestingly, the ibrutinib-resistant CLL cells remained sensitive to other BCR inhibitors such as dasatinib and SYK inhibitors. These results confirm BTK as an important pharmacologic target of ibrutinib. Further, a mechanism of resistance was revealed, and alternative therapeutic options for ibrutinib resistance were explored. (First three authors with equal contribution) Disclosures: Furman: Genentech: Consultancy, Speakers Bureau; GlaxoSmithKline: Consultancy, Speakers Bureau; Pharmacyclics: Consultancy; Gilead: Consultancy. Chang:Pharmacyclics: Employment, Equity Ownership.

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Bruton tyrosine kinase is essential for botrocetin/VWF-induced signaling and GPIb-dependent thrombus formation in vivo

Blood ◽

10.1182/blood-2006-01-011817 ◽

2006 ◽

Vol 108 (8) ◽

pp. 2596-2603 ◽

Cited By ~ 88

Author(s):

Junling Liu ◽

Malinda E. Fitzgerald ◽

Michael C. Berndt ◽

Carl W. Jackson ◽

T. Kent Gartner

Keyword(s):

Tyrosine Kinase ◽

Thrombus Formation ◽

Dependent Manner ◽

Akt Phosphorylation ◽

Atp Secretion ◽

Arterial Thrombus ◽

Bruton Tyrosine Kinase ◽

Von Willebrand ◽

Willebrand Factor

AbstractBotrocetin (bt)-facilitated binding of von Willebrand factor (VWF) to the platelet membrane glycoprotein (GP) Ib-IX-V complex on platelets in suspension initiates a signaling cascade that causes αIIbβ3 activation and platelet aggregation. Previous work has demonstrated that bt/VWF-mediated agglutination activates αIIbβ3 and elicits ATP secretion in a thromboxane A2 (TxA2)-dependent manner. The signaling that results in TxA2 production was shown to be initiated by Lyn, enhanced by Src, and propagated through Syk, SLP-76, PI3K, PLCγ2, and PKC. Here, we demonstrate that the signaling elicited by GPIb-mediated agglutination that results in TxA2 production is dependent on Bruton tyrosine kinase (Btk). The results demonstrate that Btk is downstream of Lyn, Syk, SLP-76, and PI3K; upstream of ERK1/2, PLCγ2, and PKC; and greatly enhances Akt phosphorylation. The relationship(s), if any, between ERK1/2, PLCγ2, and PKC were not elucidated. The requirement for Btk and TxA2 receptor function in GPIb-dependent arterial thrombosis was confirmed in vivo by characterizing blood flow in ferric chloride-treated mouse carotid arteries. These results demonstrate that the Btk family kinase, Tec, cannot provide the function(s) missing because of the absence of Btk and that Btk is essential for both bt/VWF-mediated agglutination-induced TxA2 production and GPIb-dependent stable arterial thrombus formation in vivo.

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Immunological Studies in Patients with Alcoholic Liver Disease: Evidence for the in vivo Activation of Helper T Cells and of the Monocyte-Macrophage System

International Archives of Allergy and Immunology ◽

10.1159/000234082 ◽

1986 ◽

Vol 80 (4) ◽

pp. 361-368 ◽

Cited By ~ 9

Author(s):

Fabrizio Spinozzi ◽

Roberto Guerciolini ◽

Roberto Gerli ◽

Ivano Gernini ◽

Francesco Rondoni ◽

...

Keyword(s):

T Cells ◽

Liver Disease ◽

Alcoholic Liver Disease ◽

Helper T Cells

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Neutrophil development and function critically depend on Bruton tyrosine kinase in a mouse model of X-linked agammaglobulinemia

Blood ◽

10.1182/blood-2010-04-281170 ◽

2011 ◽

Vol 117 (4) ◽

pp. 1329-1339 ◽

Cited By ~ 54

Author(s):

Katja Fiedler ◽

Anca Sindrilaru ◽

Grzegorz Terszowski ◽

Enikö Kokai ◽

Thorsten B. Feyerabend ◽

...

Keyword(s):

Bone Marrow ◽

Tyrosine Kinase ◽

Neutrophil Migration ◽

Edema Formation ◽

Gm Csf ◽

Bruton Tyrosine Kinase ◽

And Function ◽

Bone Marrow Chimeras ◽

Deficient Mice

Abstract Bruton tyrosine kinase (Btk) is essential for B cell development and function and also appears to be important for myeloid cells. The bone marrow of Btk-deficient mice shows enhanced granulopoiesis compared with that of wild-type mice. In purified granulocyte-monocyte-progenitors (GMP) from Btk-deficient mice, the development of granulocytes is favored at the expense of monocytes. However, Btk-deficient neutrophils are impaired in maturation and function. Using bone marrow chimeras, we show that this defect is cell-intrinsic to neutrophils. In GMP and neutrophils, Btk plays a role in GM-CSF– and Toll-like receptor–induced differentiation. Molecular analyses revealed that expression of the lineage-determining transcription factors C/EBPα, C/EBPβ, and PU.1, depends on Btk. In addition, expression of several granule proteins, including myeloperoxidase, neutrophilic granule protein, gelatinase and neutrophil elastase, is Btk-dependent. In the Arthus reaction, an acute inflammatory response, neutrophil migration into tissues, edema formation, and hemorrhage are significantly reduced in Btk-deficient animals. Together, our findings implicate Btk as an important regulator of neutrophilic granulocyte maturation and function in vivo.

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The Bruton tyrosine kinase inhibitor PCI-32765 thwarts chronic lymphocytic leukemia cell survival and tissue homing in vitro and in vivo

Blood ◽

10.1182/blood-2011-10-386417 ◽

2012 ◽

Vol 119 (5) ◽

pp. 1182-1189 ◽

Cited By ~ 408

Author(s):

Sabine Ponader ◽

Shih-Shih Chen ◽

Joseph J. Buggy ◽

Kumudha Balakrishnan ◽

Varsha Gandhi ◽

...

Keyword(s):

Chronic Lymphocytic Leukemia ◽

Tyrosine Kinase ◽

B Cell ◽

Cell Survival ◽

Lymphocytic Leukemia ◽

B Cell Malignancies ◽

Bruton Tyrosine Kinase ◽

Targeted Agent

Abstract B-cell receptor (BCR) signaling is a critical pathway in the pathogenesis of several B-cell malignancies, including chronic lymphocytic leukemia (CLL), and can be targeted by inhibitors of BCR-associated kinases, such as Bruton tyrosine kinase (Btk). PCI-32765, a selective, irreversible Btk inhibitor, is a novel, molecularly targeted agent for patients with B-cell malignancies, and is particularly active in patients with CLL. In this study, we analyzed the mechanism of action of PCI-32765 in CLL, using in vitro and in vivo models, and performed correlative studies on specimens from patients receiving therapy with PCI-32765. PCI-32765 significantly inhibited CLL cell survival, DNA synthesis, and migration in response to tissue homing chemokines (CXCL12, CXCL13). PCI-32765 also down-regulated secretion of BCR-dependent chemokines (CCL3, CCL4) by the CLL cells, both in vitro and in vivo. In an adoptive transfer TCL1 mouse model of CLL, PCI-32765 affected disease progression. In this model, PCI-32765 caused a transient early lymphocytosis, and profoundly inhibited CLL progression, as assessed by weight, development, and extent of hepatospenomegaly, and survival. Our data demonstrate that PCI-32765 effectively inhibits CLL cell migration and survival, possibly explaining some of the characteristic clinical activity of this new targeted agent.

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