The lymph node microenvironment promotes B-cell receptor signaling, NF-κB activation, and tumor proliferation in chronic lymphocytic leukemia (CLL)
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ABSTRACT: To elucidate effects of tumor host interactions in vivo in CLL, purified tumor cells were obtained concurrently from blood, bone marrow and/or lymph node and analyzed by gene expression profiling. Keywords: RNA
Project description:To elucidate effects of tumor host interactions in vivo in CLL, purified tumor cells were obtained concurrently from blood, bone marrow and/or lymph node and analyzed by gene expression profiling. Keywords: RNA Comparision of gene expression profiling in matched pairs of peripheral blood (PB) vs. bone marrow (BM) or lymph nodes (LN) derived CLL cells
Project description:Chronic lymphocytic leukemia (CLL) is a disease with a highly variable prognosis. The clinical course can however be predicted thanks to prognostic markers. Poor prognosis is associated with expression of a B cell receptor (BCR) from unmutated immunoglobulin variable heavy-chain genes (IgVH) and expression of zeta associated protein of 70 kDa (ZAP-70). The reason why ZAP-70 expression is associated with poor prognosis and whether the protein has a direct pathogenic function is at present unknown. By transfer of ZAP-70 to CLL cells, we show here that expression of ZAP-70 in CLL cells leads to increased expression of the NF-κB target genes interleukin-1β (IL-1β), IL-6 and IL-8 upon BCR triggering. This could be blocked by inhibition of NF-κB signaling through inhibition of IκB kinases (IKK). Transcriptome analysis identified a NF-κB RelA signature imposed by ZAP-70 expression in BCR stimulated CLL cells. We conclude that ZAP-70 acts directly as an amplifier of NF-κB signaling in CLL cells which could be an underlying mechanism for its association with poor prognosis and which may represent a therapeutic target.
Project description:Many functional consequences of mutations on tumor phenotypes in chronic lymphocytic leukemia (CLL) are only partially known. This is in part due to a scarcity of information on the proteome of CLL. We profiled the proteome of 117 CLL samples with data-independent acquisition mass spectrometry (DIA-MS) and integrated the results with genomic, transcriptomic, functional data and clinical outcome. We found trisomy 12 and IGHV to be major determinants of proteome variation in CLL (1055 and 542 differential proteins FDR of 5%). Trisomy 12 was associated with limited protein abundance buffering. Protein complex analyses detected functional units involved in BCR/PI3K/AKT signaling in CLL with trisomy 12. We associated protein expression with response to anticancer drugs, and STAT2 protein expression emerged as a biomarker for the prediction of response to kinase inhibitors including BTK and MEK inhibitors. STAT2 protein levels were determined by gene dosage (trisomy 12), stabilization in a protein complex and linked to interferon signaling in CLL. This study highlights the emerging importance of protein abundance profiling in CLL biology.
Project description:Chronic lymphocytic leukemia (CLL), an incurable malignancy of mature B lymphocytes, involves blood, bone marrow, and secondary lymphoid organs such as the lymph nodes (LN). A role of the tissue microenvironment in the pathogenesis of CLL is hypothesized based on in vitro observations, but its contribution in vivo remains ill-defined. To elucidate the effects of tumor-host interactions in vivo, we purified tumor cells from 24 treatment-naive patients. Samples were obtained concurrently from blood, bone marrow, and/or LN and analyzed by gene expression profiling. We identified the LN as a key site in CLL pathogenesis. CLL cells in the LN showed up-regulation of gene signatures, indicating B-cell receptor (BCR) and nuclear factor-?B activation. Consistent with antigen-dependent BCR signaling and canonical nuclear factor-?B activation, we detected phosphorylation of SYK and I?B?, respectively. Expression of BCR target genes was stronger in clinically more aggressive CLL, indicating more effective BCR signaling in this subtype in vivo. Tumor proliferation, quantified by the expression of the E2F and c-MYC target genes and verified with Ki67 staining by flow cytometry, was highest in the LN and was correlated with clinical disease progression. These data identify the disruption of tumor microenvironment interactions and the inhibition of BCR signaling as promising therapeutic strategies in CLL. This study is registered at http://clinicaltrials.gov as NCT00019370.
Project description:Several studies have demonstrated an impaired function of the microenvironment in chronic lymphocytic leukemia (CLL), contributing to immune evasion of tumor cells and disease progression. However, in CLL-like monoclonal B cell lymphocytosis (MBL) studies are scarce. Herein, a comprehensive characterization of the microenvironment in 59 MBL, 56 early stage CLL and 31 healthy controls was conducted. Gene expression arrays and qRT-PCR were performed on RNA from CD4+ peripheral blood cells; serum cytokines were measured by immunoassays and proteomic studies; and flow cytometry was applied to evaluate peripheral blood cytotoxic, Th1, exhausted and effector CD4+ T cells, besides monocytic CD14, CD4 and HLA-DR expression. MBL and early stage CLL showed a similar upregulation of cytotoxic and Th1-related genes, expanded perforin+ and CXCR3+ CD4+ T cells as well as PD1+ CD4+ T cells compared to controls. However, a strong inflammatory response was only identified in MBL: enhanced phagocytosis, pattern recognition receptors, IL8, HMGB1, TREM1 and acute response signaling pathways, along with increased levels of proinflammatory cytokines (remarkably IL8, IFN? and TNF?). Of note, this inflammatory drive was decreased in early stage CLL: diminished proinflammatory cytokines including IFN?, decreased IL8 signaling pathway and lower monocytic HLA-DR expression compared to MBL. Besides, this inflammation was especially reduced in IGHV mutated CLL, involving a decrease of the proinflammatory HMGB1 signaling pathway. These novel findings reveal a different pathophysiology between MBL and CLL, paving the way for the development of pre-emptive immunotherapies with optimal benefits at MBL and early stage CLL, before intense immune exhaustion.
Project description:Altered metabolism is a hallmark of both cell division and cancer. Chronic lymphocytic leukemia (CLL) cells circulate between peripheral blood (PB) and lymph nodes (LNs), where they receive proliferative and prosurvival signals from surrounding cells. However, insight into the metabolism of LN CLL and how this may relate to therapeutic response is lacking. To obtain insight into CLL LN metabolism, we applied a 2-tiered strategy. First, we sampled PB from 8 patients at baseline and after 3-month ibrutinib (IBR) treatment, which forces egress of CLL cells from LNs. Second, we applied in vitro B-cell receptor (BCR) or CD40 stimulation to mimic the LN microenvironment and performed metabolomic and transcriptomic analyses. The combined analyses indicated prominent changes in purine, glucose, and glutamate metabolism occurring in the LNs. CD40 signaling mostly regulated amino acid metabolism, tricarboxylic acid cycle (TCA), and energy production. BCR signaling preferably engaged glucose and glycerol metabolism and several biosynthesis routes. Pathway analyses demonstrated opposite effects of in vitro stimulation vs IBR treatment. In agreement, the metabolic regulator MYC and its target genes were induced after BCR/CD40 stimulation and suppressed by IBR. Next, 13C fluxomics performed on CD40/BCR-stimulated cells confirmed a strong contribution of glutamine as fuel for the TCA cycle, whereas glucose was mainly converted into lactate and ribose-5-phosphate. Finally, inhibition of glutamine import with V9302 attenuated CD40/BCR-induced resistance to venetoclax. Together, these data provide insight into crucial metabolic changes driven by the CLL LN microenvironment. The prominent use of amino acids as fuel for the TCA cycle suggests new therapeutic vulnerabilities.
Project description:In chronic lymphocytic leukemia (CLL), the tumor cells receive survival support from stromal cells through direct cell contact, soluble factors and extracellular vesicles. The tyrosine protein kinase Lyn, is aberrantly expressed in the malignant and stromal cells in CLL tissue. We therefore studied the role of Lyn in the EV-based communication and tumor support. We compared the Lyn-dependent EV release, uptake and functionality using Lyn-proficient and deficient stromal cells and primary CLL cells. Lyn-proficient cells caused a significantly higher EV release and EV uptake as compared to Lyn-deficient ones. Also, they induced stronger support of primary CLL cells. Proteomic comparison of the EVs from Lyn-proficient and deficient stromal cell highlighted 72 significantly differentially expressed proteins, many of which belonging to the extracellular matrix organization, such as collagen, nidogen, fibronectin and endosialin (CD248). CD248, a marker of certain tumors and of cancer associated fibroblast (CAF) was significantly depleted in Lyn-deficient HS-5 cells. A knockdown of CD248 in Lyn+ HS-5 cells resulted in a diminished B-CLL cells survival feeding capacity compared to wildtype or scrambled control cells. The presented data provide preclinical evidence, that the tyrosine kinase Lyn crucially influences the EV-based communication between stromal and primary B-CLL cells by raising the EV release and their concentration of functional molecules, such as endosialin.
Project description:Chimeric antigen receptor (CAR) T cell therapy has yielded unprecedented outcomes in some patients with hematological malignancies; however, inhibition by the tumor microenvironment has prevented the broader success of CART cell therapy. We used chronic lymphocytic leukemia (CLL) as a model to investigate the interactions between the tumor microenvironment and CART cells. CLL is characterized by an immunosuppressive microenvironment, an abundance of systemic extracellular vesicles (EVs), and a relatively lower durable response rate to CART cell therapy. In this study, we characterized plasma EVs from untreated CLL patients and identified their leukemic cell origin. CLL-derived EVs were able to induce a state of CART cell dysfunction characterized by phenotypical, functional, and transcriptional changes of exhaustion. We demonstrate that, specifically, PD-L1+ CLL-derived EVs induce CART cell exhaustion. In conclusion, we identify an important mechanism of CART cell exhaustion induced by EVs from CLL patients.