Role of phosphatidylinositol 3′-kinase/AKT pathway in diffuse large B-cell lymphoma survival

Abstract Phosphatidylinositol 3′-kinase (PI3K) is a key player in cell-growth signaling in a number of lymphoid malignancies, but its role in diffuse large B-cell lymphoma (DLBCL) has not been fully elucidated. Therefore, we investigated the role of the PI3K/AKT pathway in a panel of 5 DLBCL cell lines and 100 clinical samples. Inhibition of PI3K by a specific inhibitor, LY294002, induced apoptosis in SUDHL4, SUDHL5, and SUDHL10 (LY-sensitive) cells, whereas SUDHL8 and OCI-LY19 (LY-resistant) cells were refractory to LY294002-induced apoptosis. AKT was phosphorylated in 5 of 5 DLBCL cell lines and inhibition of PI3K caused dephosphorylation/inactivation of constitutively active AKT, FOXO transcription factor, and GSK3 in LY-sensitive cell lines. In addition, there was a decrease in the expression level of inhibitory apoptotic protein, XIAP, in the DLBCL cell lines sensitive to LY294002 after treatment. However, no effect was observed in XIAP protein levels in the resistant DLBCL cell lines following LY294002 treatment. Finally, using immunohistochemistry, p-AKT was detected in 52% of DLBCL tumors tested. Furthermore, in univariate analysis, high p-AKT expression was associated with short survival. In multivariate analysis, this correlation was no longer significant. Altogether, these results suggest that the PI3K/AKT pathway may be a potential target for therapeutic intervention in DLBCL.

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Role of Phosphatidylinositol 3- Kinase/AKT Pathway in Diffuse Large B-Cell Lymphoma Survival.

Blood ◽

10.1182/blood.v106.11.4808.4808 ◽

2005 ◽

Vol 106 (11) ◽

pp. 4808-4808

Author(s):

Shahab Uddin ◽

Azhar R. Hussain ◽

Prahant Bavi ◽

Abdul K. Siraj ◽

Khawla S. Al-Kuraya

Keyword(s):

B Cell ◽

Cell Lines ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Pi3 Kinase ◽

Phosphatidylinositol 3 Kinase ◽

Large B Cell Lymphoma ◽

Pi3 Kinase Pathway ◽

Kinase Pathway ◽

Large B Cell

Abstract Phosphatidylinositol 3-kinase (PI3-kinase) is a key player in cell growth signaling in a number of lymphoid malignancies including myeloma and primary effusion lymphoma. However, its role in diffuse large B-cell lymphoma (DLBCL) has not been elucidated. Therefore, we have studied the PI3-kinase pathway and apoptosis in a panel of DLBCL cell lines (SUDHL4, SUDHL8, SUDHL10 and OCI-LY19). Our data show that inhibition of PI3-kinase by a specific inhibitor, LY294002, induced apoptosis as detected by Annexin V/Propidium Iodide dual staining in the majority of DLBCL cell lines. We then dissected the PI3-kinase pathway by analyzing the downstream targets of phosphorylation by Western blot. We found that AKT/PKB was constitutively phosphorylated, and thus activated, in all DLBCL cell lines. The downstream elements of AKT, ForkHead (FKHR) and GSK3 were also constitutively phosphorylated in all DLBCL cell lines. Similarly, treatment with LY294002 prevented this phenomenon in all the cell lines regardless of their final apoptotic endpoint. Inhibition of PI3-kinase activity further downstream induced cleavage of Bid in all DLBCL cells and subsequently loss of mitochondrial membrane potential and release of cytochrome c from mitochondria in all DLBCL cell lines. The release of cytochrome C led to activation of Caspases 9 and 3 and cleavage of PARP. Finally expression of the inhibitor of apoptosis, XIAP, which is also a downstream target of AKT, was compromised in the all cell lines following LY294002 treatment. Our data demonstrate that the PI3-kinase pathway plays a major role in the survival and growth of DLBCL cells. Altogether, these results suggest that blocking the PI3-kinase pathway may be a potential target for therapeutic intervention in diffuse large B-cell lymphoma.

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Endogenous Neurotrophins and Trk Signaling in Diffuse Large B Cell Lymphoma Cell Lines Are Involved in Sensitivity to Rituximab-Induced Apoptosis

PLoS ONE ◽

10.1371/journal.pone.0027213 ◽

2011 ◽

Vol 6 (11) ◽

pp. e27213 ◽

Cited By ~ 18

Author(s):

Cynthia Bellanger ◽

Lydie Dubanet ◽

Marie-Claude Lise ◽

Anne-Laure Fauchais ◽

Dominique Bordessoule ◽

...

Keyword(s):

B Cell ◽

Cell Lines ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Lymphoma Cell ◽

Large B Cell Lymphoma ◽

Induced Apoptosis ◽

Large B Cell

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Anti-Apoptotic Bcl2 and Bcl-Xl Proteins Involved in Stroma-Induced Drug Tolerance to Hsp70 and Hsp90 Inhibitors in Leukemia and B-Cell Lymphoma

Blood ◽

10.1182/blood.v120.21.4900.4900 ◽

2012 ◽

Vol 120 (21) ◽

pp. 4900-4900

Author(s):

Eloisi Caldas Lopes ◽

Fabian M Correa ◽

Ling-Bo Shen ◽

Jae-Hung Shieh ◽

Tony Taldone ◽

...

Keyword(s):

B Cell ◽

Cell Lines ◽

Stromal Cells ◽

Stromal Cell ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Hsp90 Inhibitor ◽

Large B Cell Lymphoma ◽

Induced Apoptosis ◽

Large B Cell

Abstract Abstract 4900 Background: Multiple studies have demonstrated that the bone marrow stromal microenvironment contributes to the survival of hematologic malignant cells, eventually leading to relapse. However, molecular mechanisms associated with this stromal niche remain unclear. The human bone marrow stromal cell lines, HS-5 and HS-27, provide physical contact with hematologic cells, while HS-5 cells secrete more growth factors and cytokines than HS-27 stromal cells. Our objective is to dissect the mechanisms underlying stromal-mediated drug tolerance in leukemia and lymphoma cells, which could potentially lead to novel therapies for various leukemia. Methods and Results: A panel of leukemia and B-cell lymphoma cell lines were used in this project, including Kasumi1 (AML: Acute Myeloid Leukemia) and OCILy1 (DLBCL: Diffuse Large B-Cell Lymphoma) cells and their respective sub-lines resistant to heat shock protein-70 and −90 (HSP70/90) inhibitors. To determine the ability of stromal cell lines to confer tolerance to HSP-inhibitors, Kasumi1 and OCILy1 (sensitive and resistant) cells were cultured alone or in the presence of the HS-27 or HS-5 cells with HSP70 inhibitor or HSP90 inhibitor for 48h. The resulting cultures were then harvested and analyzed for apoptosis and by western blot. Both HS-5 and HS-27 stromal cells markedly protected OCILy1 and Kasumi1 cells from HSP70 inhibitor induced apoptosis. At a dose of 0.5 μM, % apoptotic cells were 74.0±1.6% for OCILy1 alone, 38.3±2.1% for OCILy1 with HS-5 and 42.2±1.8% for OCILY1 with HS-27. At a dose of 1 μM of HSP90 inhibitor, apoptosis rate are 61.9±1.5% for OCILy1 alone, 28.2±2.2% for OCILy1 with HS-5 and 36.4±1.9% for OCILy1 with HS-27. A similar HSP inhibitor induced apoptosis was also observed in Kasumi1 cells. In contrast, both Kasumi1 and OCILy1 HSP70/90 inhibitor resistant sub-lines in the presence or absence of the stromal cells did not respond to treatment with respective inhibitors. Further study reveals the stromal cells up-modulated the expression of the anti-apoptotic proteins Bcl2 and Bcl-xL in both Kasumi and OCILY1 cells. Conclusions: Our results demonstrate that the stromal niche is able to mediate tolerance to HSP70 and HSP90 inhibitors in Leukemia and B-cell lymphoma via up-regulation of antiapoptotic proteins such as Bcl2 and Bcl-xL. The Bcl2 protein is deregulated and plays a crucial role in diffuse large B-cell lymphoma (DLBCL) with the t(14;18) translocation. Our finding elucidates one of the drug-specific mechanisms that suggest a promising combination therapy targeting both HSP70 and HSP90 to reduce antineoplastic resistance and relapse, and thereby improve survival for patients with leukemia and lymphoma. Disclosures: No relevant conflicts of interest to declare.

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ROR1 is Expressed in Diffuse Large B-Cell Lymphoma (DLBCL) and a Small Molecule Inhibitor of ROR1 (KAN0441571C) Induced Apoptosis of Lymphoma Cells

Biomedicines ◽

10.3390/biomedicines8060170 ◽

2020 ◽

Vol 8 (6) ◽

pp. 170

Author(s):

Amineh Ghaderi ◽

Amir Hossein Daneshmanesh ◽

Ali Moshfegh ◽

Parviz Kokhaei ◽

Jan Vågberg ◽

...

Keyword(s):

B Cell ◽

Cell Lines ◽

Small Molecule ◽

Cell Lymphoma ◽

International Prognostic Index ◽

Prognostic Index ◽

B Cell Lymphoma ◽

Large B Cell Lymphoma ◽

Induced Apoptosis ◽

Large B Cell

The receptor tyrosine kinase ROR1 is absent in most normal adult tissues, but overexpressed in several malignancies. In this study, we explored clinical and functional inhibitory aspects of ROR1 in diffuse large B-cell lymphoma (DLBCL). ROR1 expression in tumor cells was more often observed in primary refractory DLBCL, Richter’s syndrome and transformed follicular lymphoma than in relapsed and non-relapsed DLBCL patients (p < 0.001). A survival effect of ROR1 expression was preliminarily observed in relapsed/refractory patients independent of gender and stage but not of age, cell of origin and international prognostic index. A second generation small molecule ROR1 inhibitor (KAN0441571C) induced apoptosis of ROR1+ DLBCL cell lines, similar to venetoclax (BCL-2 inhibitor) but superior to ibrutinib (BTK inhibitor). The combination of KAN0441571C and venetoclax at EC50 concentrations induced almost complete killing of DLBCL cell lines. Apoptosis was accompanied by the downregulation of BCL-2 and MCL-1 and confirmed by the cleavage of PARP and caspases 3, 8, 9. PI3Kδ/AKT/mTOR (non-canonical Wnt pathway) as well as β-catenin and CK1δ (canonical pathway) were inactivated. In zebra fishes transplanted with a ROR1+ DLBCL cell line, KAN0441571C induced a significant tumor reduction. New drugs with mechanisms of action other than those available for DLBCL are warranted. ROR1 inhibitors might represent a novel promising approach.

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The phosphodiesterase PDE4B limits cAMP-associated PI3K/AKT–dependent apoptosis in diffuse large B-cell lymphoma

Blood ◽

10.1182/blood-2004-01-0240 ◽

2005 ◽

Vol 105 (1) ◽

pp. 308-316 ◽

Cited By ~ 90

Author(s):

Peter G. Smith ◽

Fengfei Wang ◽

Kathryn N. Wilkinson ◽

Kerry J. Savage ◽

Ulf Klein ◽

...

Keyword(s):

B Cell ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Lymphoid Malignancies ◽

Large B Cell Lymphoma ◽

Constitutively Active Mutants ◽

B Lymphoid ◽

Induced Apoptosis ◽

Large B Cell

Abstract Diffuse large B-cell lymphoma (DLBCL) is a common and often fatal malignancy. Advances in the treatment of this disease will require the identification of novel therapeutic targets. We previously defined an expression signature of outcome in DLBCL and found that the phosphodiesterase PDE4B was overexpressed in fatal/refractory tumors. Phosphodiesterase 4B (PDE4B) inactivates the second messenger cyclic adenosine 3′,5′ monophosphate (cAMP) and abrogates its inhibitory effects in B lymphocytes. Hence, DLBCLs that express high PDE4B levels may be resistant to cAMP-induced apoptosis, contributing to their less favorable outcome. Herein, we confirmed the risk-related expression of PDE4B in an independent series of primary DLBCLs and defined the enzyme's role in modulating cAMP-induced apoptosis in parental DLBCL cell lines or those reconstituted with wild-type or mutant PDE4B. The cAMP-mediated apoptosis of DLBCLs was largely independent of the previously described cAMP effectors, protein kinase A (PKA) and exchange protein directly activated by cAMP (EPAC), but associated with inhibition of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway. The central role of AKT in this process was confirmed by expressing constitutively active mutants of this kinase in DLBCL cells. Our findings highlight the important role of cAMP signaling in DLBCL and suggest that clinically relevant PDE4 and PI3K/AKT inhibitors might be useful in the treatment of DLBCL and additional B-lymphoid malignancies with increased PDE4B expression. (Blood. 2005;105:308-316)

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