Transformation of Chronic Lymphocytic Leukemia Towards Richter´s Syndrome Is Induced By AKT Activation

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2031-2031
Author(s):  
Nadine Nickel ◽  
Mona Al-Maarri ◽  
Martin Pal ◽  
Andreas Roth ◽  
Gero Knittel ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Research Funding ◽  
Akt Signaling ◽  
Lymphocytic Leukemia ◽  
Transformed Cells ◽  
Positive Staining ◽  
Akt Activation ◽  
Richter Syndrome ◽  
Support Research

Abstract Richter's syndrome (RS) is an aggressive transformation of Chronic Lymphocytic Leukemia (CLL) to Diffuse Large B Cell Lymphoma (DLBCL) refractory to current therapies with dismal prognosis. Richter Syndrome arises from CLL cells independent of common DLBCL mutations. Frequently, mutations in p53, CDKN2 or cMyc genes are involved, but a significant proportion displays no specifically acquired driver mutation. We could observe activation of AKT in 6 out 48 Richter syndrome biopsies by positive staining for active phosphorylated AKT while in CLL lymph nodes, DLBCL and Burkitt´s Lymphoma no phospho-AKT by IHC could be observed. However in primary patient CLL cases we could detect varying levels of pAKT by Western blot, elevated levels were identified predominantly in patients harboring high-risk mutations such p53, ATM, NOTCH1 and XPO1. Furthermore, B-cell receptor mediated stimulation of the PI3K/AKT axis provided protection towards genotoxic stress induced apoptosis via post-translation stabilization of MCL1. This provides subsequently a synergistic induction of apoptosis by combining idelalisib and bendamustin. Thus we analyzed the functional impact of AKT signaling using a conditional constitutive allele for AKT (AKT-C) specifically activated using CD19-Cre and Cγ1-Cre fro post-GC-activation. AKT activation alone could not induce a malignant phenotype, however we could demonstrate that Eµ-Tcl-1 mice with AKT-C develop Richter Syndrome. Both in EµTCL1:CD19-CreAKT-C (TCA) and EµTCL1:Cγ1- CreAKT-C (TCγ1A) mice developed a high-grade lymphoma phenotype leading to decreased survival. Transformed cells displayed blastoid characteristics with significantly increased cellular size and the histomorphological features of DLBCL. Large transformed cells show high percentage of KI67-positive staining (>90%) and frequent mitotic figures. Here, AKT-mediated GSK-3b inhibition and subsequent cMyc and Mcl-1 stabilization might transform CLL to RS cells and combinatory treatments with DNA-damaging and PI3K-inhibiting compounds revealed promising therapeutic results. Collectively, we have identified AKT signaling as an oncogenic signaling pathway in progression of CLL towards Richter´s syndrome and generated the first murine Richter Syndrome model (TCA and TCγ1A) providing novel mechanistic insights into the molecular understanding of Richter's transformation that is amenable to model therapeutic strategies and to address the efficacy of synergistic treatment combinations. Disclosures Klapper: Roche, Novartis, Amgen, Takeda: Research Funding. Hallek:Amgen: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Mundipharma: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau.

Heritable Predisposition To Richter Syndrome In Patients With Chronic Lymphocytic Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2867-2867 ◽  
Author(s):  
Sameer A. Parikh ◽  
Susan L Slager ◽  
Kari G. Rabe ◽  
Neil E. Kay ◽  
James R Cerhan ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Research Funding ◽  
B Cell Lymphoma ◽  
Lymphocytic Leukemia ◽  
Chromosome 18 ◽  
Richter Syndrome ◽  
Increased Risk ◽  
Translocation Breakpoints

Abstract Background Approximately 2-8% patients with chronic lymphocytic leukemia (CLL) will transform to diffuse large B-cell lymphoma (DLBCL, Richter syndrome [RS]). Clinical characteristics and molecular markers at the time of CLL diagnosis are associated with the risk of RS; however, there are no data regarding germline genetic variations and the risk of RS. Genomewide association studies (GWAS) have shown several single-nucleotide polymorphisms (SNPs) that are associated with a higher risk of familial CLL. It is not known whether any of these polymorphisms also predispose to RS. Methods Since 2002, all consecutive patients with newly diagnosed (<9 months diagnosis) CLL at Mayo Clinic were offered enrollment into a prospective genetic epidemiology study. Patients completed extensive epidemiologic questionnaires and baseline clinical, laboratory, and biologic data were abstracted using a standard protocol. Genotyping of germline tissue at diagnosis was performed using an Illumina iSelect panel and Affymetrix 6.0 SNP chip. All patients were prospectively and longitudinally followed at defined time-points with systematic collection of data on treatments, second cancers, and RS. All patients with biopsy-proven DLBCL during follow-up were considered to have undergone transformation into RS. Time to RS was calculated from CLL diagnosis date until RS or until last follow-up date for those with no RS. SNPs were modeled in two ways: ordinal and dominant. Cox regression was used to estimate hazard ratio (HR) for individual SNPs with time to transformation. Results Thirteen of the GWAS-discovered SNPs associated with risk of developing CLL were available and genotyped on 620 CLL patients. Median age at diagnosis of CLL was 62 years (range 27-88), and 428 (69%) were male. Three hundred and ten (51%) patients were low (0) Rai stage, 271 (45%) were intermediate (I-II) Rai stage, and 22 (4%) were advanced (III-IV) Rai stage. The immunoglobulin heavy chain gene was unmutated in 189 (40%) patients; 157 (32%) patients expressed ZAP-70, 163 (29%) expressed CD38 and 104 (31%) expressed CD49d. Fluorescence in-situ hybridization (FISH) revealed that 210 (41%) patients had del13q, 90 (18%) patients had trisomy 12, 37 (7%) had del11q, 23 (5%) had del17p and 141 (28%) had no detectable FISH abnormalities. As of last follow-up, 239 (39%) patients received therapy for CLL. After a median follow-up of 5.9 years (range 0-11), 15 (2.4%) patients developed biopsy-proven RS. The median time to RS in these 15 patients was 4.5 years (range 1.0-8.7 years). The ordinal HR for the 13 SNPs tested, their corresponding genes, and p-values are shown in Table 1. Germline polymorphisms in a single SNP, rs4987852, encoding for BCL2 (chromosome 18), was significantly associated with an increased risk of RS (ordinal HR=3.9; 95% CI=1.6-9.8; p-value=0.004). This allele was present in 48/605 (8%) non-transformed CLL patients compared to 4/15 (27%) of patients with RS. Time to RS according to the Kaplan-Meier analysis for rs4987852 is shown in Figure 1. This SNP is located in a region in which t(14;18) translocation breakpoints commonly occur in follicular lymphoma and overexpression of BCL2 leads to an increased incidence of B-cell lymphomas in mice. Conclusion Our results suggest that inherited genetic polymorphisms predispose CLL patients to develop RS. Specifically, SNP (rs4987852) present on the BCL2 gene on chromosome 18 in CLL is associated with an increased risk of transformation to RS. These observations require replication in other CLL cohorts. Disclosures: Shanafelt: Genentech: Research Funding; Glaxo-Smith-Kline: Research Funding; Cephalon: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Polyphenon E International: Research Funding.

IKZF3 Overexpression Phenocopies Gain-of-Function Mutation in Chronic Lymphocytic Leukemia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 9-9
Author(s):  
Shanye Yin ◽  
Gregory Lazarian ◽  
Elisa Ten Hacken ◽  
Tomasz Sewastianik ◽  
Satyen Gohil ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chronic Lymphocytic Leukemia ◽  
Dna Binding ◽  
B Cell ◽  
Board Of Directors ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Advisory Committees ◽  
Bcr Signaling ◽  
Experimental Group

A hotspot mutation within the DNA-binding domain of IKZF3 (IKZF3-L162R) has been identified as a putative driver in chronic lymphocytic leukemia (CLL); however, its functional effects are unknown. We recently confirmed its role as a CLL driver in a B cell-restricted conditional knock-in model. IKZF3 mutation altered mature B cell development and signaling capacity, and induced CLL-like disease in elderly mice (~40% penetrance). Moreover, we found IKZF3-L162R acts as a gain-of-function mutation, altering DNA binding specificity and target selection of IKZF3, and resulting in overexpression of multiple B-cell receptor (BCR) genes. Consistent with the murine data, RNA-sequencing analysis showed that human CLL cells with mut-IKZF3 [n=4] have an enhanced signature of BCR-signaling gene expression compared to WT-IKZF3 [n=6, all IGHV unmutated] (p&lt;0.001), and also exhibited general upregulation of key BCR-signaling regulators. These results confirm the role of IKZF3 as a master regulator of BCR-signaling gene expression, with the mutation contributing to overexpression of these genes. While mutation in IKZF3 has a clear functional impact on a cardinal CLL-associated pathway, such as BCR signaling, we note that this driver occurs only at low frequency in patients (~3%). Because somatic mutation represents but one mechanism by which a driver can alter a cellular pathway, we examined whether aberrant expression of IKZF3 could also yield differences in BCR-signaling gene expression. We have observed expression of the IKZF3 gene to be variably dysregulated amongst CLL patients through re-analysis of transcriptomic data from two independent cohorts of human CLL (DFCI, Landau et al., 2014; ICGC, Ferreira et al., 2014). We thus examined IKZF3 expression and BCR-signaling gene expression, or the 'BCR score' (calculated as the mean expression of 75 BCR signaling-associate genes) in those cohorts (DFCI cohort, n=107; ICGC cohort, n=274). Strikingly, CLL cells with higher IKZF3 expression (defined as greater than median expression) had higher BCR scores than those with lower IKZF3 expression (&lt;median) (p=0.0015 and p&lt;0.0001, respectively). These findings were consistent with the notion that IKZF3 may act as a broad regulator of BCR signaling genes, and that IKZF3 overexpression, like IKZF3 mutation, may provide fitness advantage. In support of this notion, our re-analysis of a gene expression dataset of 107 CLL samples (Herold Leukemia 2011) revealed that higher IKZF3 expression associated with poorer prognosis and worse overall survival (P=0.035). We previously reported that CLL cells with IKZF3 mutation appeared to increase in cancer cell fraction (CCF) with resistance to fludarabine-based chemotherapy (Landau Nature 2015). Instances of increase in mut-IKZF3 CCF upon treatment with the BCR-signaling inhibitor ibrutinib have been reported (Ahn ASH 2019). These studies together suggest an association of IKZF3 mutation with increased cellular survival following either chemotherapy or targeted treatment. To examine whether higher expression of IKZF3 was associated with altered sensitivity to ibrutinib, we performed scRNA-seq analysis (10x Genomics) of two previously treatment-naïve patients undergoing ibrutinib therapy (paired samples, baseline vs. Day 220). We analyzed an average of 11,080 cells per patient (2000 genes/cell). Of note, following ibrutinib treatment, remaining CLL cells expressed higher levels of IKZF3 transcript compared to pretreatment baseline (both p&lt;0.0001), whereas no such change was observed in matched T cells (n ranging between 62 to 652 per experimental group, p&gt;0.05), suggesting that cells with high expression of IKZF3 were selected by ibrutinib treatment. Moreover, we showed that ibrutinib treatment resulted in consistent upregulation of BCR-signaling genes (e.g., CD79B, LYN, GRB2, FOS, RAC1, PRKCB and NFKBIA) (n ranging between 362 to 1374 per experimental group, all p&lt;0.0001), which were likewise activated by mutant IKZF3. Altogether, these data imply that IKZF3 mutation or overexpression may influence upregulation of BCR-signaling genes and enhance cellular fitness even during treatment with BCR-signaling inhibitors. We highlight our observation that IKZF3 mutation appears to be phenocopied by elevated IKZF3 expression, and suggest that alterations in mRNA or protein level that mimic genetic mutations could be widespread in human cancers. Disclosures Kipps: Pharmacyclics/ AbbVie, Breast Cancer Research Foundation, MD Anderson Cancer Center, Oncternal Therapeutics, Inc., Specialized Center of Research (SCOR) - The Leukemia and Lymphoma Society (LLS), California Institute for Regenerative Medicine (CIRM): Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech/Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; VelosBio: Research Funding; Oncternal Therapeutics, Inc.: Other: Cirmtuzumab was developed by Thomas J. Kipps in the Thomas J. Kipps laboratory and licensed by the University of California to Oncternal Therapeutics, Inc., which provided stock options and research funding to the Thomas J. Kipps laboratory, Research Funding; Ascerta/AstraZeneca, Celgene, Genentech/F. Hoffmann-La Roche, Gilead, Janssen, Loxo Oncology, Octernal Therapeutics, Pharmacyclics/AbbVie, TG Therapeutics, VelosBio, and Verastem: Membership on an entity's Board of Directors or advisory committees. Wu:BionTech: Current equity holder in publicly-traded company; Pharmacyclics: Research Funding.

Fcgammariib Expression As a Prognostic Marker in Chronic Lymphocytic Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1727-1727
Author(s):  
Rosa Bosch ◽  
Gerardo Ferrer ◽  
Eva Puy Vicente ◽  
Alba Mora ◽  
Rajendra N. Damle ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Clinical Outcome ◽  
B Cell ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Disease Stage ◽  
Advanced Stage ◽  
Fcγ Receptor ◽  
Expression Levels

Abstract BACKGROUND The Fcγ receptor IIb (FcγRIIb) is an inhibitory Fcγ receptor that suppresses B-cell activation when coligated with B-cell antigen receptor (BCR). Previous studies from our group indicate that the ability of the FcγRIIb to inhibit BCR signaling after coligation is attenuated in Chronic Lymphocytic Leukemia (CLL). Furthermore, in contrast to what has been described in normal murine B-cells, stimulation of the FcγRIIb alone induces proliferation of CLL cells. However, the correlation between FcγRIIb expression, immunophenotypic characteristics, and clinical variables in patients with CLL has not been studied. AIM The aim of this study was to correlate the expression of FcγRIIb on leukemic cells from previously untreated CLL patients and its immunophenotypic features and clinical parameters. METHODS The study population included 112 patients with untreated CLL for whom cryopreserved peripheral blood samples were available before treatment. The diagnosis was based on IWCLL 2008 criteria. The median patients' follow up was 57.92 months (range: 2.23-439.78 months). FcγRIIb expression levels were determined by flow cytometry on CD5+/CD19+ CLL cells using a specific Alexa488-conjugated murine mAb specific for human FcγRIIb. The following combinations were assessed: FcγRIIb/CD38/CD19/CD5, FcγRIIb/CD49d/CD19/CD5, and FcγRIIb/CD69/CD19/CD5. Results were expressed as the ratio between the MFI for FcγRIIb and the MFI for the corresponding isotype (MFIR). FcγRIIb expression levels were correlated with: i) expression of CD49d, CD38 and CD69, ii) clinico-biological characteristics, and iii) clinical outcome. Differences of FcγRIIb expression on dichotomized clinicopathological variables were assessed with Mann Whitney test. Kaplan-Meier survival and Cox regression analysis were performed to evaluate the correlation of FcγRIIb expression with clinical outcome. Best cut-offs for overall survival (OS) and treatment-free survival (TFS) were determined by ROC curves. RESULTS All CD5+CD19+ leukemic cells samples expressed FcγRIIb. However, FcγRIIb expression levels markedly varied between patients (median MFIR: 45.8; interquartile range: 14.9-76.6; 5th -95th percentile: 17.15-111.4). FcγRIIb expression was significantly higher in patients who had high (≥30%) CD49d expression than in those with low (<30%) CD49d expression (p =0.009). No correlation was observed between FcγRIIb expression and age, disease stage, IGHV mutational status or chromosomal abnormalities analyzed by fluorescence in situ hybridization, ZAP70 and CD38. Furthermore, within individual clones, FcγRIIb expression levels were higher on CD38+ or CD49d+ cells than on CD38- or CD49d- cells, respectively (median MFIR: 49.05 vs. 36.72, p =0.001 for CD38+ vs. CD38- cells; and 58.87 vs. 35.55, p <0.001 for CD49d+ vs. CD49d- cells). In univariate analysis, low FcγRIIb expression levels (MFIR< 26.67) were associated with shorter OS (HR 4.01, 95%CI 1.15-13.90, p=0.029), together with older age, advanced stage, and expression of CD38 and CD49d. Advanced stage, unmutated IGHV, and CD38, CD49d and ZAP-70 expression were also associated significantly with shorter TFS. Thus, patients with higher levels of FcγRIIb had better survival than those with lower levels (Log rank test, p = 0.018). A multivariate analysis adjusted for FcγRIIb expression, age, disease stage, CD38, and CD49d identified older age (≥65 yrs) (HR 150.76, 95%CI 5.39-4212.42, p =0.003), low FcγRIIb expression (HR 111.91, 95%CI 6.71-1866.97, p =0.001), advanced stage (B/C) (HR 17.44, 95%CI 1.45-210.24, p =0.024) and CD38 expression (HR 5.02, 95%CI 1.01-25.18, p =0.050) as independent predictors for shorter OS. CONCLUSIONS In this study, FcγRIIb expression on leukemic cells from untreated patients with CLL was found to be an independent prognostic marker for OS, overcoming the prognostic value of CD49d, which is consistent with the key role of the FcγRIIb in the pathogenesis of CLL. Further analysis aimed at validating this observation and to better understand the functional cooperation of FcγRIIb with other molecules, particularly CD49d, are warranted. These studies could open a new venue in CLL treatment. Disclosures Gorlatov: MacroGenics: Employment. Sierra:Novartis: Research Funding; Celgene: Research Funding; Amgen: Research Funding.

scholarly journals Stereotyped B-Cell Receptor Is an Independent Risk Factor of Chronic Lymphocytic Leukemia Transformation to Richter Syndrome

2009 ◽  
Vol 15 (13) ◽  
pp. 4415-4422 ◽  
Author(s):  
Davide Rossi ◽  
Valeria Spina ◽  
Michaela Cerri ◽  
Silvia Rasi ◽  
Clara Deambrogi ◽  
...  
Keyword(s):  
Risk Factor ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Independent Risk Factor ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Lymphocytic Leukemia ◽  
Richter Syndrome

scholarly journals Cirmtuzumab Targets ROR1 to Inhibit Ibrutinib-Resistant, Wnt5a-Induced Rac1 Activation in Chronic Lymphocytic Leukemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2034-2034 ◽  
Author(s):  
Jian Yu ◽  
Liguang Chen ◽  
Bing Cui ◽  
Christina Wu ◽  
Michael Y. Choi ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Research Funding ◽  
Standard Dose ◽  
Leukemia Cell ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Human Leukemia ◽  
Synergistic Activity ◽  
Bcr Signaling

Abstract Signaling via the B cell receptor (BCR) plays an important role in the pathogenesis and progression of chronic lymphocytic leukemia (CLL). This is underscored by the clinical effectiveness of an inhibitor of Bruton's tyrosine kinase (BTK), ibrutinib, which can block BCR-signaling. However, ibrutinib cannot induce complete responses (CR) or durable remissions without continued therapy, suggesting that ancillary pathways contribute to CLL growth/survival that are independent of BCR-signaling. ROR1 is a receptor for Wnt5a, which can promote activation of Rac1 to enhance CLL-cell proliferation and survival. We hypothesized that the effects of ibrutinib on blocking BCR-signaling might be offset by non-canonical Wnt-signaling via ROR1. If so, then inhibition of both ROR1- and BCR-signaling might have an enhanced anti-tumor effect. We examined the CLL cells of patients who were taking ibrutinib at the standard dose of 420 mg per day. Freshly isolated CLL cells had activated Rac1, which diminished over time upon culture in serum-free media, unless treated with exogenous Wnt5a, as noted for CLL cells of patients not taking ibrutinib. Moreover, Wnt5a could induce Rac1 activation and enhance proliferation of CLL cells treated in vitro with ibrutinib, even at concentrations that exceeded those required to completely inhibit BTK and BCR-signaling. On the other hand, Wnt5a-induced activation of Rac1 was blocked by treatment of the CLL cells with cirmtuzumab (UC-961), a first-in-class humanized mAb specific for a functional extracellular epitope of ROR1; this mAb is being evaluated in a phase I clinical trial in patients with CLL. To examine the activity of ibrutinib and/or cirmtuzumab, alone or in combination, we transferred human CLL cells into the peritoneal cavity of immune-deficient Rag2−/−γc−/− mice, which subsequently were treated with ibrutinib via oral gavage and/or cirmtuzumab administered iv. Although either agent alone resulted in some leukemia-cell clearance, cirmtuzumab and ibrutinib had apparent synergistic activity when used together in clearing human leukemia cells. We also examined the activity of each agent, alone or in combination, against a ROR1+ mouse leukemia, which we had engrafted in Rag2−/−γc−/− mice. While the engrafted mice treated with cirmtuzumab or ibrutinib alone had significantly smaller spleens and lower proportions of leukemia cells than the engrafted animals that did not receive any treatment, the mice treated with the combination of cirmtuzumab and ibrutinib had significantly smaller spleens and synergistic clearance of leukemia cells. Collectively, this study demonstrates that cirmtuzumab and ibrutinib may have synergistic activity in the treatment of patients with CLL, providing the rationale for clinical trials using cirmtuzumab in combination with ibrutinib, or another inhibitor of BTK, such as acalabrutinib, for treatment of patients with CLL or other B-cell malignancies dependent on non-canonical Wnt5a/ROR1 signaling. Disclosures Kipps: Celgene: Consultancy, Honoraria, Research Funding; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding.

Inhibition Of PI3K-δ and -γ Isoforms By IPI-145 In Chronic Lymphocytic Leukemia Overcomes Signals From PI3K/AKT/S6 Pathway and Promotes Apoptosis

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4167-4167 ◽  
Author(s):  
Kumudha Balakrishnan ◽  
Marisa Peluso ◽  
Min Fu ◽  
Nathalie Y. Rosin ◽  
Jan A. Burger ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Research Funding ◽  
Therapeutic Potential ◽  
Lymphocytic Leukemia ◽  
B Cell Malignancies ◽  
Employment Equity ◽  
Enhanced Production ◽  
Significant Difference ◽  
Equity Ownership

Abstract The functional relevance of the B cell Receptor (BCR) pathway and identification of protein kinases as therapeutic targets have recently shifted the paradigm for treatment of B cell malignancies. Inhibition of protein and lipid kinases (Bruton Tyrosine Kinase [BTK] and phosphoinositide 3-kinase [PI3K]) with ibrutinib and GS-1101 has been shown to be active in treatment of chronic lymphocytic leukemia (CLL). Importantly, differential expression and function of PI3K isoforms support isoform-selective inhibition of this kinase in CLL. Whilst PI3K-α and PI3K-β are ubiquitously expressed, PI3K-δ and PI3K-γ are primarily restricted to leukocytes. Since CLL cells generally express high levels of active PI3K-δ, great interest has been focused on inhibition of PI3K-δ. However, given the distinct and non-overlapping roles of PI3K-δ and PI3K-γ in immune cells, exploration of the therapeutic potential of combined inhibition of both PI3K-δ and PI3K-γ in CLL patients is warranted. IPI-145 is a potent, orally bioavailable, inhibitor of PI3K-δ and PI3K-γ isoforms with KD values of 0.023 nM and 0.24 nM, respectively. Treatment of primary CLL cells (n=51) with IPI-145 (1 µM) resulted in significant apoptosis (median 33%; range 12 – 40%). Patients with mutated (n=13) or unmutated IGHV gene status (n=13), previously untreated (n=21) or treated (n=8), displayed no significant difference in apoptosis from IPI-145. Samples with different prognostic markers such as 13q (del) or FISH negative samples were equally sensitive to IPI-145. Side by side studies of IPI-145 with ibrutinib and GS-1101, revealed that IPI-145 is comparatively potent (IC50 7.6 µM, compared to >10 µM) in promoting apoptosis. Crosslinking with anti-IgM enhanced the survival of primary CLL cells in association with activation of PI3K-δ,γ/AKTSer473/pBadSer136/S6Ser235/236 pathway, which was in turn mitigated upon treatment with IPI-145 (n=9). Consistent with cell death, cleavage of PARP and decrease in anti-apoptotic protein Mcl-1 (but not Bcl-2 or Bcl-xL) was observed. Measurement of the C-C chemokine, CCL3, a biomarker for BCR signaling inhibition in CLL, demonstrated 15 to 48 – fold increase upon anti-IgM stimulation, which was reversed when cells were treated with 1 µM IPI-145 (10 to 80-fold decrease; n=6). Alternatively, co-culturing CLL primary cells with bone marrow stromal cells to mimic the leukemic microenvironment induced the protein levels of all four Class I PI3K isoforms and downstream PI3K/AKT/S6 signaling axis, which was significantly attenuated by IPI-145. To mimic the proliferative state in lymph node pseudofollicles, CLL cells were stimulated to proliferate with CD40L/IL-2/IL-10 and the effect of IPI-145 was measured. Both pAKT and Ki-67 expression were markedly inhibited in primary CLL cells at concentrations of IPI-145 in the low nanomolar range (EC50<10nM; n=2), suggesting a potent anti-proliferative effect of IPI-145 on CLL cells in the nodal environment. Given the significant role of the chemo-attractant, SDF-1, in the directed migration of B-cells, chemotaxis assay demonstrated reduction in migration of CLL cells towards SDF-1 in presence of IPI-145 (% control reduction - median 23%; range 2-42%; n=8). Furthermore, IPI-145 treatment enhanced production of reactive oxygen species (n=6). Taken together, these results demonstrate the potential of combined inhibition of the PI3K-δ and -γ isoforms in CLL, and support clinical investigation of IPI-145 in B-cell malignancies, including CLL. Disclosures: Balakrishnan: Infinity Pharmaceuticals Inc: Research Funding. Peluso:Infinity Pharmaceuticals., Inc.: Employment, Equity Ownership. Faia:Infinity Pharmaceuticals., Inc.: Employment, Equity Ownership. Kutok:Infinity Pharmaceuticals., Inc.: Employment, Equity Ownership. McGovern:Infinity Pharmaceuticals., Inc.: Employment, Equity Ownership. Gandhi:Infinity Pharmaceuticals., Inc: Research Funding.

CD38 is a signaling molecule in B-cell chronic lymphocytic leukemia cells

Blood ◽  
2003 ◽  
Vol 102 (6) ◽  
pp. 2146-2155 ◽  
Author(s):  
Silvia Deaglio ◽  
Andrea Capobianco ◽  
Luciana Bergui ◽  
Jan Dürig ◽  
Fortunato Morabito ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Membrane Lipid ◽  
Lymphocytic Leukemia ◽  
Specific Expression ◽  
Cellular Models ◽  
Richter Syndrome ◽  
Cell Chronic Lymphocytic Leukemia

Abstract The prognosis for patients with B-cell chronic lymphocytic leukemia (B-CLL) is generally less favorable for those expressing CD38. Our working hypothesis is that CD38 is not merely a marker in B-CLL, but that it plays a receptor role with pathogenetic potential ruling the proliferation of the malignant clone. CD38 levels were generally low in the patients examined and monoclonal antibody (mAb) ligation was inefficient in signaling. Other cellular models indicated that molecular density and surface organization are critical for CD38 functionality. Interleukin 2 (IL-2) induced a marked up-modulation and surface rearrangement of CD38 in all the patients studied. On reaching a specific expression threshold, CD38 becomes an efficient receptor in purified B-CLL cells. Indeed, mAb ligation is followed by Ca2+ fluxes and by a markedly increased proliferation. The unsuitability of CD38 to perform as a receptor is obviated through close interaction with the B-cell–receptor (BCR) complex and CD19. On mAb binding, CD38 translocates to the membrane lipid microdomains, as shown by a colocalization with the GM1 ganglioside and with CD81, a raft-resident protein. Finally, CD38 signaling in IL-2–treated B-CLL cells prolonged survival and induced the appearance of plasmablasts, providing a pathogenetic hypothesis for the occurrence of Richter syndrome.

scholarly journals Developmental DNA Methylation Subtype Predicts Progression to Treatment and Survival in High-Count Monoclonal B Lymphocytosis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3022-3022
Author(s):  
Brian Giacopelli ◽  
Kari G. Chaffee ◽  
Yue-zhong Wu ◽  
John C. Byrd ◽  
Tait D. Shanafelt ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Overall Survival ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Research Funding ◽  
Data Safety Monitoring Board ◽  
Lymphocytic Leukemia ◽  
State University ◽  
High Count ◽  
University Patents

Monoclonal B cell lymphocytosis (MBL) has been shown to be the precursor condition that precedes overt diagnosis of chronic lymphocytic leukemia (CLL). Whereas CLL is classified with greater than or equal to 5 × 109/L B lymphocytes in the peripheral blood, MBL is a clonal expansion of B-cells below this threshold. MBL can be further divided into high- or low-count based on whether the B-cell count is above or below 0.5 × 109/L. Approximately 10% of the population over 40 is estimated to have MBL, increasing to >50% over the age of 90. While low-count MBL is unlikely to progress, 1-2% of high-count (HC) MBL individuals progress to CLL requiring therapy per year. It is debatable if all patients with detectable MBL should be classified as an entity requiring monitoring by a hematologist, especially for low-count MBL. In addition, the diagnosis of leukemia is distressing to patients; therefore, it is important to identify HC MBL patients that are more likely to progress to disease requiring treatment and thus should be monitored more closely. As the majority of MBL cases phenotypically resemble CLL, established prognostic markers including recurrent chromosomal aberrations, beta-2 microglobulin levels, and the mutational status of the Immunoglobulin heavy-chain variable region locus (IGHV) have been shown to predict time to treatment (TTT) and overall survival (OS) in a large retrospective study of MBL1. CLL patients can also be divided into three distinct epigenetic subtypes that reflect progressive DNA methylation changes that occurs during B cell development. These 'epitypes' termed low-programmed (LP), intermediate-programmed (IP), and high-programmed (HP) independently predict clinical outcomes irrespective of disease stage and treatment2. LP-CLL patients follow a generally unfavorable clinical course compared to the more indolent HP-CLL patients, while IP CLL patients display an intermediate outcome. Here we sought to determine if epitype forecasts progression to CLL and eventual clinical outcome for individuals with MBL. We analyzed 66 individuals diagnosed with HC MBL at the Mayo Clinic with a median follow-up of 6.3 years. Developmental epitype was determined using our novel Methylation-iPLEX technique that interrogates 34 CpGs and assigns epitype using a random forest model2. Seventy-seven percent of the MBL cases were assigned to one of the three epitypes: 42.4% HP, 19.7% IP, and 15.2% LP. The residual 23% remained unclassified due to ambiguous (low confidence) epigenetic patterns or insufficient purity (Figure 1A). The overall proportion of HP and IP epitypes in MBL were significantly greater than proportions observed in CLL cohorts (P<0.01). Epitypes remained stable over time as 20/21 cases for which we obtained a high-confidence epitype classification at multiple time points remained unchanged. Epitype significantly predicted MBL individuals progressing to treatment (P=0.001) with LP individuals progressing in a median of 5.6 years (P=0.049 and P=0.0002 versus IP and HP, respectively); median was not reached in HP or IP (Figure 1B). Epitype also predicted overall survival (OS) in MBL (P=0.04), with LP individuals having a significantly shorter OS (median of 11 years versus not reached in IP and HP; P=0.056 and P=0.048 versus IP and HP, respectively). In this study we evaluated a cohort of 66 HC MBL cases and determined that classification using developmental DNA methylation epitypes can be employed in HC MBL to aid in risk stratification. HC MBL patients classified as LP are more likely to progress to requiring treatment and have a significantly reduced OS. The epigenetic classification may help clinicians decide how closely and frequently a HC MBL individual needs to be monitored. Figure 1: (A) Breakdown of the epigenetic subtype assigned to 66 HC MBL samples. (B) Kaplan-Meier analysis of time to treatment and (C) overall survival of MBL patients separated by epitype. 1. Parikh, S. A. et al. Outcomes of a large cohort of individuals with clinically ascertained high-count monoclonal B-cell lymphocytosis. Haematologica103, e237-e240 (2018). 2. Giacopelli, B. et al. Developmental subtypes assessed by DNA methylation-iPLEX forecast the natural history of chronic lymphocytic leukemia. Blood blood.2019000490 (2019). doi:10.1182/blood.2019000490 Disclosures Byrd: Ohio State University: Patents & Royalties: OSU-2S; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; BeiGene: Research Funding; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Novartis: Other: Travel Expenses, Speakers Bureau; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Genentech: Research Funding; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; Novartis: Other: Travel Expenses, Speakers Bureau; Ohio State University: Patents & Royalties: OSU-2S; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; Acerta: Research Funding; Genentech: Research Funding; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; Acerta: Research Funding. Shanafelt:Patent: Patents & Royalties: US14/292,075 on green tea extract epigallocatechin gallate in combination with chemotherapy for chronic lymphocytic leukemia; Merck: Research Funding; Polyphenon E International: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding; Hospira: Research Funding; Glaxo-SmithKline: Research Funding; Abbvie: Research Funding; Cephalon: Research Funding; Celgene: Research Funding. Parikh:Genentech: Honoraria; Janssen: Research Funding; AstraZeneca: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; MorphoSys: Research Funding; AbbVie: Honoraria, Research Funding; Acerta Pharma: Research Funding; Ascentage Pharma: Research Funding. Kay:Agios: Other: DSMB; MorphoSys: Other: Data Safety Monitoring Board; Infinity Pharmaceuticals: Other: DSMB; Celgene: Other: Data Safety Monitoring Board.

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