
pmid: 39143370
pmc: PMC11436378
handle: 11368/3085358 , 20.500.11770/371659 , 2108/379824 , 20.500.11769/654730 , 11579/202411
pmid: 39143370
pmc: PMC11436378
handle: 11368/3085358 , 20.500.11770/371659 , 2108/379824 , 20.500.11769/654730 , 11579/202411
In chronic lymphocytic leukemia (CLL), survival of neoplastic cells depends on microenvironmental signals at lymphoid sites where the crosstalk between the integrin VLA-4 (CD49d/CD29), expressed in ~40% of CLL, and the B-cell receptor (BCR) occurs. Here, BCR engagement inside-out activates VLA-4, thus enhancing VLA-4-mediated adhesion of CLL cells, which in turn obtain pro-survival signals from the surrounding microenvironment. We report that the BCR is also able to effectively inside-out activate the VLA-4 integrin in circulating CD49d-expressing CLL cells through an autonomous antigen-independent BCR signaling. As a consequence, circulating CLL cells exhibiting activated VLA-4 express markers of BCR pathway activation (phospho-BTK and phospho-PLC-γ2) along with higher levels of phospho-ERK and phospho-AKT indicating parallel activation of downstream pathways. Moreover, circulating CLL cells expressing activated VLA-4 bind soluble blood-borne VCAM-1 leading to increased VLA-4-dependent actin polymerization/re-organization and ERK phosphorylation. Finally, evidence is provided that ibrutinib treatment, by affecting autonomous BCR signaling, impairs the constitutive VLA-4 activation eventually decreasing soluble VCAM-1 binding and reducing downstream ERK phosphorylation by circulating CLL cells. This study describes a novel anchor-independent mechanism occurring in circulating CLL cells involving the BCR and the VLA-4 integrin, which help to unravel the peculiar biological and clinical features of CD49d+ CLL.
570, Real-time analysis: receptor stereotypy; CD49d; survival; activation; expression; CLL; proliferation; Ibrutinib; CD38, proliferation, 610, Receptors, Antigen, B-Cell, Vascular Cell Adhesion Molecule-1, Integrin alpha4beta1, Ligands, survival, Article, Piperidines, expression, Cell Adhesion, Humans, /96 ; Adenine/pharmacology [MeSH] ; Vascular Cell Adhesion Molecule-1/metabolism [MeSH] ; Leukemia, Lymphocytic, Chronic, B-Cell/metabolism [MeSH] ; Pyrazoles/therapeutic use [MeSH] ; /13 ; /631/67/1990/283/1895 ; Leukemia, Lymphocytic, Chronic, B-Cell/pathology [MeSH] ; Ligands [MeSH] ; /38/109 ; Receptors, Antigen, B-Cell/metabolism [MeSH] ; /13/31 ; Pyrimidines/pharmacology [MeSH] ; Adenine/analogs ; Neoplastic Cells, Circulating/pathology [MeSH] ; /82/80 ; Cell Adhesion [MeSH] ; Humans [MeSH] ; Pyrazoles/pharmacology [MeSH] ; /13/106 ; Neoplastic Cells, Circulating/metabolism [MeSH] ; Integrin alpha4beta1/metabolism [MeSH] ; Article ; Signal Transduction [MeSH] ; /631/80/86 ; /14 ; article ; Piperidines/pharmacology [MeSH], Adenine, Ibrutinib, CD49d, Settore MED/15, Neoplastic Cells, Circulating, Real-time analysis: receptor stereotypy, Leukemia, Lymphocytic, Chronic, B-Cell, Pyrimidines, Pyrazoles, activation, CLL, CD38, Signal Transduction
570, Real-time analysis: receptor stereotypy; CD49d; survival; activation; expression; CLL; proliferation; Ibrutinib; CD38, proliferation, 610, Receptors, Antigen, B-Cell, Vascular Cell Adhesion Molecule-1, Integrin alpha4beta1, Ligands, survival, Article, Piperidines, expression, Cell Adhesion, Humans, /96 ; Adenine/pharmacology [MeSH] ; Vascular Cell Adhesion Molecule-1/metabolism [MeSH] ; Leukemia, Lymphocytic, Chronic, B-Cell/metabolism [MeSH] ; Pyrazoles/therapeutic use [MeSH] ; /13 ; /631/67/1990/283/1895 ; Leukemia, Lymphocytic, Chronic, B-Cell/pathology [MeSH] ; Ligands [MeSH] ; /38/109 ; Receptors, Antigen, B-Cell/metabolism [MeSH] ; /13/31 ; Pyrimidines/pharmacology [MeSH] ; Adenine/analogs ; Neoplastic Cells, Circulating/pathology [MeSH] ; /82/80 ; Cell Adhesion [MeSH] ; Humans [MeSH] ; Pyrazoles/pharmacology [MeSH] ; /13/106 ; Neoplastic Cells, Circulating/metabolism [MeSH] ; Integrin alpha4beta1/metabolism [MeSH] ; Article ; Signal Transduction [MeSH] ; /631/80/86 ; /14 ; article ; Piperidines/pharmacology [MeSH], Adenine, Ibrutinib, CD49d, Settore MED/15, Neoplastic Cells, Circulating, Real-time analysis: receptor stereotypy, Leukemia, Lymphocytic, Chronic, B-Cell, Pyrimidines, Pyrazoles, activation, CLL, CD38, Signal Transduction
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