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  • 1
    Online Resource
    Online Resource
    American Society of Hematology ; 2018
    In:  Blood Vol. 132, No. Supplement 1 ( 2018-11-29), p. 3117-3117
    In: Blood, American Society of Hematology, Vol. 132, No. Supplement 1 ( 2018-11-29), p. 3117-3117
    Abstract: Dysregulation of cancer cell bioenergetics is one of the hallmarks of cancer. The Warburg effect is one such documented change. However, glucose metabolism is not universally increased in cancer cells. Uptake of radiolabelled glucose in chronic lymphocytic leukaemia (CLL) fails as a marker of proliferation and the underlying reason is not well elucidated [Conte et al, 2014]. Using proteomic and comprehensive lipid analyses, the preferred metabolic pathways of CLL cells have been identified. We have previously shown by proteomic analysis that circulating peripheral blood CLL cells demonstrate a significant increase in the expression of proteins pivotal in endogenous lipid synthesis pathways compared to B-cells from healthy individuals. These include fatty acid synthase (+3.84 fold), farnesyl diphosphate synthase (+2.17 fold), ATP-citrate lyase (+4.63 fold), citrate synthase (+2.45 fold) and acetyl-CoA acetyltransferase 1 (+5.84 fold). Conversely, analysis of the proliferation centres in CLL lymph nodes reveals increased expression of proteins involved in beta-oxidation, such as hydroxyacyl-CoA dehydrogenase (+2.02 fold). Additionally CLL cells shows a large increase in the levels of phospholipids found associated with lipid droplets compared to healthy B-cells, including phosphatidylinositol and phosphatidylethanolamine. Our current studies have expanded these observations in an attempt to determine if CLL cells have a preponderance for endogenous synthesis of lipids or exogenous uptake. We performed a comprehensive analysis of CLL cells from the bone marrow and peripheral blood using a variety of techniques. Transmission electron microscopy (TEM) images demonstrate striking morphological differences between normal B-cells and CLL cells with the inclusion of lipid droplets in the cytoplasm of CLL cells (Figure 1A) which was most evident in peripheral CLL samples. These were confirmed to be lipid droplets by the specific marker Bodipy 493/503 on flow cytometry (Fig. 1B) and confocal microscopy imaging with ReZolveL1 which targets neutral lipids (Fig. 1C). These showed a substantially higher level of lipid droplet staining in CLL cells compared to normal B-cells. Additionally there was higher expression of CD36 in CLL cells which is the receptor for exogenous lipid uptake into cells (Fig 1D). TEM analysis also revealed a high number of lysosomes in CLL cells, which was confirmed with lysotracker imaging on confocal microscopy (Fig. 1E). Lysosomes are now emerging as key players in lipid transport and biogenesis [Thelen and Zoncu, 2017]. Lipid droplets may be broken down by a process called autophagy mediated lipid degradation, or lipophagy, which relies on autophagosomes delivering lipid droplets to lysosomes. Autophagosomes were observed in several further bone marrow samples (Fig. 1F). The bone marrow samples also showed evidence of 'condensed mitochondria', indicative of high rates of beta-oxidation [Rossignol et al, 2004] . qPCR was then carried out on 90 genes involved in lipid metabolism. These results revealed significant differences between healthy B-cells and CLL cells. All CLL samples analysed demonstrated high expression of PLIN1, which protects lipid droplets from degradation, and low expression of APOC1, which prevents fatty acid uptake. From these observations we propose that peripheral CLL cells scavenge lipids from the periphery, mainly by uptake via the CD36 receptor, and increased endogenous lipid synthesis pathways. These results underpin a model for metabolism and enhanced survival for CLL cells in the hypoxic and potentially nutrient poor bone marrow/lymph node microenvironments. Peripheral CLL cells scavenge lipids; these excess lipids, which are toxic to the cell, are stored in lipid droplets which are protected from degradation by a high expression of PLIN proteins. Once these cells circulate back to the bone marrow and lymph nodes to proliferate, the lipid droplets are degraded, likely by lipophagy and neutral lipolysis which frees fatty acids to be used in beta oxidation in the mitochondria to sustain cell proliferation in the bone marrow and lymph node compartments. Our results begin to unravel CLL bioenergetics and dysregulation of cellular metabolism that occurs in this disease. We are now investigating whether the manipulation of these pathways, particularly lipophagy, may represent a novel therapeutic approach in CLL. Disclosures No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2018
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 2
    In: Blood, American Society of Hematology, Vol. 122, No. 21 ( 2013-11-15), p. 3111-3111
    Abstract: The 2-3 fold excess risk of multiple myeloma (MM) among family members of cases suggests a heritable contribution to risk. Recently, a genome-wide association study (GWAS) identified two genome-wide significant and one promising novel loci associated with multiple myeloma risk. To confirm these associations and identify additional novel risk loci, we performed a four-center, genome-wide association meta-analysis. Methods A fixed effects model was used for the meta-analysis which included a total of 1248 cases and 1485 controls, all of European descent, genotyped and analyzed at four separate centers with samples contributed by 10 studies. After quality control and imputation using the 1000 Genomes Project, the analysis included ∼9.5 million variants (λ=1.024). Associations between (single nucleotide polymorphisms) SNP genotypes and MM risk were evaluated under a log-additive model of inheritance, with each study adjusting for age, sex, and up to 10 principal components to control for population stratification. Promising results were replicated in an independent set of 1587 cases and 1770 controls using TaqMan, for a total of 2835 and 3255 cases and controls, respectively, in a combined meta-analysis. Results The discovery meta-analysis did not reveal any genome-wide significant associations (defined as p 〈 5 x 10-8). We used a novel pruning algorithm to identify the top 35 most promising single nucleotide polymorphisms (SNPs) to advance to replication. We successfully genotyped 22 SNPs in the replication set. In the combined discovery and replication meta-analysis, rs1345359 at 12q23.1 was the most strongly associated SNP (P=9 x 10-8, Table 1). The variant allele C was associated with reduced risk (odds ratio discovery set [OR]= 0.69, OR replication set = 0.78, OR combined = 0.74). A second locus at 20q13.2 (rs150220835), was associated with a two-fold increased risk (P=1.22 x 10-6), a borderline increased risk (P=0.0900) and 45% increased risk (P=2.44 X 10-5) in the discovery, replication, and combined analysis sets respectively (Table 1). We also confirmed the association between MM risk and two previously published SNPs (rs4487645, p=0.0007and rs105251, p=0.0044) (Broderick et al., Nat. Genet., 2011). The third previously suggested SNP (rs6746082) was of nominal significance (p=0.0517) in the meta-analysis. Discussion We confirmed the association between MM risk and two previously published SNPs and identified a possible association with a novel SNP in chromosome 12q23.1 (rs1345359). This SNP is not located in a gene nor associated with biofeatures in ENCODE, thus further examination of correlated SNPs is necessary to identify a functional SNP linked to this locus. We also found suggestive evidence for a second locus at 20q13.2 requiring additional replication. Larger studies would improve risk variant discovery for this rare hematologic malignancy. Disclosures: Wolf: Celgene: Honoraria, Research Funding; Millenium: Honoraria; Onyx: Honoraria. Anderson:Celgene, Millennium, BMS, Onyx: Membership on an entity’s Board of Directors or advisory committees; Acetylon, Oncopep: Scientific Founder , Scientific Founder Other.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2013
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 3
    In: Blood, American Society of Hematology, Vol. 131, No. 23 ( 2018-06-07), p. 2541-2551
    Abstract: PRS, based on the known CLL loci, predicts CLL risk with high discrimination. This PRS predicts risk of monoclonal B-cell lymphocytosis, a precursor to CLL and a condition that has clinical impact beyond risk for CLL.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2018
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 4
    In: Blood Advances, American Society of Hematology, Vol. 4, No. 1 ( 2020-01-14), p. 87-99
    Abstract: Transcriptional profile of LCH CD1a+CD207+ DCs is most closely related to that of CD1c+ mDCs in the blood. Lineage tracing with BRAFV600E and HLA-DQB2 expression supports CD1c+ mDCs as precursors to LCH CD1a+CD207+ DCs.
    Type of Medium: Online Resource
    ISSN: 2473-9529 , 2473-9537
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2020
    detail.hit.zdb_id: 2876449-3
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  • 5
    In: Blood, American Society of Hematology, Vol. 128, No. 21 ( 2016-11-24), p. 2533-2537
    Abstract: A BRAF gene fusion and small in-frame BRAF deletions were found in a subset of LCH lesions lacking BRAF-V600E or MAP2K1 mutations. In LCH model systems, responses to MAPK pathway inhibitors depend on the specific genetic alteration that drives ERK activation.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2016
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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