scholarly journals Inhibition of B-cell receptor signaling disrupts cell adhesion in mantle cell lymphoma via RAC2

2021 ◽  
Vol 5 (1) ◽  
pp. 185-197
Author(s):  
Wenjun Wu ◽  
Weige Wang ◽  
Carrie A. Franzen ◽  
Hui Guo ◽  
Jimmy Lee ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
B Cell ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Xenograft Model ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Mantle Cell ◽  
Bcr Signaling

Abstract Inhibition of the B-cell receptor (BCR) signaling pathway is highly effective in B-cell neoplasia through Bruton tyrosine kinase inhibition by ibrutinib. Ibrutinib also disrupts cell adhesion between a tumor and its microenvironment. However, it is largely unknown how BCR signaling is linked to cell adhesion. We observed that intrinsic sensitivities of mantle cell lymphoma (MCL) cell lines to ibrutinib correlated well with their cell adhesion phenotype. RNA-sequencing revealed that BCR and cell adhesion signatures were simultaneously downregulated by ibrutinib in the ibrutinib-sensitive, but not ibrutinib-resistant, cells. Among the differentially expressed genes, RAC2, part of the BCR signature and a known regulator of cell adhesion, was downregulated at both the RNA and protein levels by ibrutinib only in sensitive cells. RAC2 physically associated with B-cell linker protein (BLNK), a BCR adaptor molecule, uniquely in sensitive cells. RAC2 reduction using RNA interference and CRISPR impaired cell adhesion, whereas RAC2 overexpression reversed ibrutinib-induced cell adhesion impairment. In a xenograft mouse model, mice treated with ibrutinib exhibited slower tumor growth, with reduced RAC2 expression in tissue. Finally, RAC2 was expressed in ∼65% of human primary MCL tumors, and RAC2 suppression by ibrutinib resulted in cell adhesion impairment. These findings, made with cell lines, a xenograft model, and human primary lymphoma tumors, uncover a novel link between BCR signaling and cell adhesion. This study highlights the importance of RAC2 and cell adhesion in MCL pathogenesis and drug development.

The BCR-Associated Tyrosine Kinase SYK Is Linked to the Activation of AKT in Mantle Cell Lymphoma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1586-1586
Author(s):  
Martina Rudelius ◽  
Denise Sebasigari ◽  
Yoko Tabe ◽  
Theresa Davies-Hill ◽  
Falko Fend ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Negative Regulator ◽  
Akt Pathway ◽  
Akt Activation ◽  
Mantle Cell ◽  
Bcr Signaling

Abstract Mantle cell lymphoma (MCL) is comprised of two major clinical-pathologic subtypes, the more common typical MCL and the blastoid variant (bv-MCL). We recently demonstrated that the PI3K/AKT pathway is preferentially activated in bv-MCL. In all bv-MCL cases, activated phosphorylated AKT (p-AKT) expression was accompanied by the phosphorylation of downstream targets, and pharmacological inhibition of the pathway abrogated or reduced the phosphorylation of AKT and its targets and resulted in cell cycle arrest and apoptosis. Activation of the pathway was neither the result of mutations in the p110 PI3K catalytic subunit, nor the loss of the negative regulator PTEN, in the majority of cases. Since the B-cell receptor (BCR) signaling pathway has been shown to be a major activator of the AKT pathway via SYK/PI3K interactions, the goal of the current study was to gain insight into its possible role in MCL. Initial studies revealed activated SYK in 4 MCL cell lines studied, and immunoprecipitation studies showed a linkage between SYK, the adaptor protein BCAP, and the p85 regulatory subunit of PI3K. To analyze a possible causal connection between SYK and AKT activation, we used both a classical inhibitor approach [piceatannol and SYK-II (Calbiochem)] and a targeted gene knockdown approach employing a lentiviral mirRNA delivery system in two cell lines (Z138C and Granta 519). Functional knock-down and downstream effects were analyzed by western blotting, assessment of PIP3 levels, MTT-test, and flow-cytometry. Using the two approaches, we could block the activation of PI3K/AKT pathway and phosphorylation of AKT downstream targets in the two MCL cell lines, indicating the importance of the B-cell receptor associated SYK kinase in activation of the PI3K/AKT pathway. Activation of BCR signaling components, including SYK, PLCγ2, and LYN, were then assessed by western blotting in 28 primary MCL cases (12 typical and 16 blastoid). Phosphorylated (active) SYK and PLCγ2 (a direct SYK target) were detected in all 28 primary cases (12 blastoid and 16 typical). Surprisingly, there were no significant differences between the two groups, despite the difference in their AKT status. However, there was a distinct difference in the activation state of LYN, as assessed by its phosphorylation at Tyr 396, which was correlated with AKT activation. While Tyr 396 was phosphorylated in the majority of typical MCL, the converse was true for the bv-MCL and cell lines, suggesting that LYN was inactive in the latter. Although LYN has been shown to have both positive and negative roles in BCR activation, the net effect of loss of LYN activity is hyperactivation of B-cell signaling. Given the consistent effect of SYK inhibition on the activity of the PI3K/AKT pathway in the cell lines, we hypothesize that loss of a negative regulator downstream of SYK, possibly LYN, is additionally required to allow activation of the PI3K/AKT pathway in MCL.

scholarly journals Differential B-Cell Receptor Signaling Requirement for Adhesion of Mantle Cell Lymphoma Cells to Stromal Cells

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1143 ◽  
Author(s):  
Laia Sadeghi ◽  
Gustav Arvidsson ◽  
Magali Merrien ◽  
Agata M. Wasik ◽  
André Görgens ◽  
...  
Keyword(s):  
B Cell ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Stromal Cells ◽  
Cell Lymphoma ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Model Framework ◽  
Lymphoma Cells ◽  
Mantle Cell

Interactions between lymphoma cells and stromal cells play a key role in promoting tumor survival and development of drug resistance. We identified differences in key signaling pathways between the JeKo-1 and REC-1 mantle cell lymphoma (MCL) cell lines, displaying different patterns of stromal cell adhesion and chemotaxis towards stroma-conditioned medium. The identified adhesion-regulated genes reciprocated important aspects of microenvironment-mediated gene modulation in MCL patients. Five-hundred and ninety genes were differently regulated between the cell lines upon adhesion to stromal cells, while 32 genes were similarly regulated in both cell lines. Regulation of B-cell Receptor (BCR) signature genes in adherent cells was specific for JeKo-1. Inhibition of BCR using siRNA or clinically approved inhibitors, Ibrutinib and Acalabrutinib, decreased adhesion of JeKo-1, but not REC-1 cells. Cell surface levels of chemokine receptor CXCR4 were higher in JeKo-1, facilitating migration and adhesion of JeKo-1 but not REC-1 cells. Surface levels of ICAM1 adhesion protein differ for REC-1 and JeKo-1. While ICAM1 played a positive role in adherence of both cell lines to stromal cells, S1PR1 had an inhibitory effect. Our results provide a model framework for further investigation of mechanistic differences in patient-response to new pathway-specific drugs.

scholarly journals A B-cell receptor-related gene signature predicts response to ibrutinib treatment in mantle cell lymphoma cell lines

Haematologica ◽  
2019 ◽  
Vol 104 (9) ◽  
pp. e410-e414
Author(s):  
Tiziana D’Agaro ◽  
Antonella Zucchetto ◽  
Filippo Vit ◽  
Tamara Bittolo ◽  
Erika Tissino ◽  
...  
Keyword(s):  
B Cell ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Cell Receptor ◽  
Gene Signature ◽  
B Cell Receptor ◽  
Related Gene ◽  
Mantle Cell Lymphoma Cell ◽  
Mantle Cell

scholarly journals Differential B-cell receptor signaling requirement for adhesion of mantle cell lymphoma cells to stromal cells

2020 ◽  
Author(s):  
Laia Sadeghi ◽  
Gustav Arvidsson ◽  
Magali Merrien ◽  
Agata M. Wasik ◽  
André Görgens ◽  
...  
Keyword(s):  
B Cell ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Stromal Cells ◽  
Cell Lymphoma ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Model Framework ◽  
Lymphoma Cells ◽  
Mantle Cell

AbstractInteractions between lymphoma cells and stromal cells play a key role in promoting tumor survival and development of drug resistance. We identified differences in key signaling pathways between the JeKo-1 and REC-1 mantle cell lymphoma (MCL) cell lines, which exhibited different patterns of stromal cell adhesion and chemotactic migration towards stroma-conditioned medium. The identified adhesion-regulated genes reciprocated important aspects of microenvironment-mediated gene modulation in MCL patients. 590 genes were differently regulated between the cell lines upon adhesion to stromal cells, while 32 genes were similarly regulated in both cell lines. Regulation of B-cell Receptor (BCR) signature genes in adherent cells was specific for JeKo-1. Inhibition of BCR signaling by siRNA or clinically approved inhibitors, Ibrutinib and Acalabrutinib, decreased adhesion of JeKo-1 but not REC-1 cells to stromal cells. Cell surface levels of CXCR4 were higher in JeKo-1 cells and CXCR4 was important for migration and adhesion of JeKo-1 but not REC-1 cells. Surface levels of ICAM1 adhesion protein differ for REC-1 and JeKo-1. While ICAM1 plays a positive role in adherence of both cell lines to stromal cells, S1PR1 had an inhibitory effect. The results presented here provide a model framework for further investigation of mechanistic differences in patient-response to new pathway-specific drugs.

scholarly journals Protein Kinase CK1α Sustains B-Cell Receptor Signaling in Mantle Cell Lymphoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Sabrina Manni ◽  
Anna Fregnani ◽  
Laura Quotti Tubi ◽  
Zaira Spinello ◽  
Marco Carraro ◽  
...  
Keyword(s):  
B Cells ◽  
Protein Kinase ◽  
B Cell ◽  
Mantle Cell Lymphoma ◽  
Cell Lymphoma ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Signaling Cascades ◽  
Mantle Cell ◽  
Bcr Signaling

Mantle Cell Lymphoma (MCL) is still an incurable B-cell malignancy characterized by poor prognosis and frequent relapses. B Cell Receptor (BCR) signaling inhibitors, in particular of the kinases BTK and PI3Kγ/δ, have demonstrated clinically meaningful anti-proliferative effects in B cell tumors. However, refractoriness to these drugs may develop, portending a dismal prognosis. Protein kinase CK1α is an emerging pro-growth enzyme in B cell malignancies. In multiple myeloma, this kinase sustains β-catenin and AKT-dependent survival and is involved in the activation of NF-κB in B cells. In this study, we analyzed the role of CK1α on MCL cell survival and proliferation, on the regulation of BCR-related BTK, NF-κB, PI3K/AKT signaling cascades and the effects of CK1α chemical inhibition or gene silencing in association with the BTK inhibitor Ibrutinib or the PI3Kγ/δ inhibitor Duvelisib. CK1α was found highly expressed in MCL cells as compared to normal B cells. The inactivation/loss of CK1α caused MCL cell apoptosis and proliferation arrest. CK1α sustained BCR signaling, in particular the NF-κB, AKT and BTK pathways by modulating the phosphorylation of Ser 652 on CARD11, Ser 536 p65 on NF-κB, Ser 473 on AKT, Tyr 223 on BTK, as well as the protein levels. We also provided evidence that CK1α-mediated regulation of CARD11 and BTK likely implicates a physical interaction. The combination of CK1α inhibition with Ibrutinib or Duvelisib synergistically increased cytotoxicity, leading to a further decrease of the activation of BCR signaling pathways. Therefore, CK1α sustains MCL growth through the regulation of BCR-linked survival signaling cascades and protects from Ibrutinib/Duvelisib-induced apoptosis. Thus, CK1α could be considered as a rational molecular target for the treatment of MCL, in association with novel agents.

Stabilization of β-catenin upon B-cell receptor signaling promotes NF-kB target genes transcription in mantle cell lymphoma

Oncogene ◽  
2020 ◽  
Vol 39 (14) ◽  
pp. 2934-2947
Author(s):  
Gregory Lazarian ◽  
Chloe Friedrich ◽  
Anne Quinquenel ◽  
Julie Tran ◽  
Souhail Ouriemmi ◽  
...  
Keyword(s):  
B Cell ◽  
Mantle Cell Lymphoma ◽  
Target Genes ◽  
Cell Lymphoma ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Receptor Signaling ◽  
Mantle Cell ◽  
B Cell Receptor Signaling ◽  
Cell Receptor Signaling

scholarly journals Inhibition of B-Cell Receptor Signaling Disrupts Cell Adhesion in Mantle Cell Lymphoma Via RAC2

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1369-1369
Author(s):  
Weige Wang ◽  
Franzen Carrie ◽  
Hui Guo ◽  
Jimmy Lee ◽  
Yan Li ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
B Cell ◽  
Cell Lines ◽  
Research Funding ◽  
Cell Receptor ◽  
Resistant Cell ◽  
Advisory Committees ◽  
Tumor Tissues ◽  
Mantle Cell ◽  
Bcr Signaling

Abstract Background: B-cell receptor (BCR) signaling pathway is recognized as a crucial pathway for the pathogenesis of neoplastic B-cells. Inhibition of the BCR signaling and the downstream pathway is highly effective in B-cell malignancy through Bruton tyrosine kinase inhibition by ibrutinib. In addition to cell proliferation inhibition, ibrutinib disrupts cell adhesion between tumor and its microenvironment through unknown molecular mechanisms, resulting in peripheral lymphocytosis with accompanying lymphadenopathy reduction in patients who receive ibrutinib. Methods and materials: In an effort to elucidate the link between BCR signaling and cell adhesion phenotype, we first characterized ibrutinib sensitive and resistant mantle cell lymphoma (MCL) cell lines. We measured cell proliferation and cell growth, and correlated ibrutinib sensitivity with cell adhesion disruption. We then used RNA-sequencing to identify differential pathways between sensitive or resistant cell lines in response to ibrutinib treatment. We validated RNA-Seq findings using cell lines, as well as animal models and human primary MCL tumor tissues and cells. Results: We found that intrinsic sensitivities of MCL cell lines to ibrutinib correlated well with their cell adhesion phenotype. RNA-sequencing revealed that BCR and cell adhesion gene signatures were simultaneously down-regulated by ibrutinib in ibrutinib-sensitive but not ibrutinib-resistant cell lines. Among the differentially expressed genes in the BCR gene signature, we identified and validated that RAC2, a regulator of cell adhesion, was down-regulated at both RNA and protein levels by ibrutinib only in ibrutinib-sensitive cells. Physical association of RAC2 with BLNK, an early BCR pathway adaptor, was disrupted by ibrutinib uniquely in sensitive cells. RAC2 knockdown with siRNA impaired cell adhesion while RAC2 over-expression rescued ibrutinib-induced reduction in cell adhesion. In a xenograft mouse model, mice treated with ibrutinib demonstrated tumor growth retardation along with down-regulation in RAC2 protein expression. Using immunohistochemical staining, we demonstrated that RAC2 was expressed in ~65% primary MCL tumor tissues with majority of RAC2-positive tumors characterized as being the more aggressive subtypes. Finally, primary MCL cells treated with ibrutinib demonstrated reduced RAC2 that is accompanied by cell adhesion impairment. Conclusions: Our findings uncover a novel cross-talk between BCR signaling and cell adhesion. Ibrutinib inhibits cell adhesion via down-regulation of RAC2. Our study highlights the importance of RAC2 and cell adhesion in MCL pathogenesis and new drug development. Disclosures Wang: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno: Research Funding; AstraZeneca: Consultancy, Research Funding; MoreHealth: Consultancy; Pharmacyclics: Honoraria, Research Funding; Novartis: Research Funding; Dava Oncology: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Kite Pharma: Research Funding; Acerta Pharma: Honoraria, Research Funding.

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