Survival In Chronic Lymphocytic Leukemia Research Articles

Integrative Transcriptome and Quantitative Proteome Analyses Identify METTL3 As a Key Regulator for Aberrant RNA Processing in Chronic Lymphocytic Leukemia

Aberrant mRNA processing is known to drive the pathogenesis of chronic lymphocytic leukemia (CLL). Recurrent gene mutations in the RNA splicing factor SF3B1 and widespread RNA intronic polyadenylation impact genome-wide gene expression and inactivate tumor suppressors, respectively. Nevertheless, how mRNA processing is regulated and exerts its function in CLL remain elusive. To comprehensively characterize the role of mRNA processing in CLL, we performed RNA sequencing (RNA-seq) and Tandem Mass Tag (TMT) proteomics using normal and CLL B cells derived from healthy donors (n=5) and untreated CLL patients (n=22). We detected 328 proteins differentially expressed between normal and CLL B cells (|Log2FC|>0.58, q<0.05). Gene set enrichment analysis (GSEA) revealed that proteins involved in RNA metabolism (transcription, splicing, modification, 3'end processing, nuclear export, decay) were upregulated in CLL, while those impacting translation were downregulated. These findings were validated by immunoblotting in an independent set of samples (n=10). However, we observed no significant gene expression changes of RNA metabolism at the transcript level, indicating that regulation of these proteins occurred post-transcriptionally. Since N6-methyladenosine (m6A) is the most abundant RNA internal modification and has emerged as a key regulator for RNA metabolism, we sought to determine whether m6A is dysregulated in CLL cells. With an m6A dotblot assay and HPLC-MS, we consistently detected increased level of m6A in mRNA from CLL cells compared with normal B cells. As one of the most upregulated proteins in CLL, METTL3 writes m6A and promotes translation efficiency through its writer and reader functions, respectively. When we knocked down (KD) METTL3 in CLL cell lines (HG3, MEC1) as well as in primary CLL cells, we observed significant cell death and growth disadvantage in CLL compared to control cells, highlighting METTL3 is essential for CLL survival. We next examined whether KD of METTL3 affects m6A and RNA translation using m6A dotblot and O-propargyl-puromycin run on assays. Loss of METTL3 had subtle impact on m6A levels but it significantly decreased protein translation (t test, p<0.01) in all the cell lines tested (HG3, MEC1, JeKo-1, Mino). To define the target protein that METTL3 affects, we performed an integrated Ribosome profiling and RNA-seq analysis using HG3 and Mino cells with or without METTL3. At both transcriptome and translatome levels, loss of METTL3 significantly decreased genes enriched in the mTORC1 pathway, which has an essential role in translation (Metascape, hypergeometric test, q<0.05). Furthermore, it also decreased the translation efficiencies of genes involved in mRNA processing, DNA synthesis, and cell cycle pathways. This observation suggests that upregulation of METTL3 in CLL cells may regulate protein translation of the RNA metabolism pathway. Since m6A at the stop codon region is critical for METTL3 regulating protein translation, we performed MAZTER sequencing to determine m6A modification sites in normal and CLL B cells derived from healthy donors (n=5) and untreated CLL patients (n=11). We identified 214 genes with significant differential m6A modification at the stop codon region (delta cleavage efficiency>0.1, Wilcoxon rank-sum test, p<0.1, within DRACA motif) between normal and CLL B cells. These genes were highly enriched for mRNA processing (Metascape, q=0.017), supporting our notion that METTL3 may modulate protein expression of mRNA processing genes by recognizing m6A modification via its reader function in CLL. Consistent with its role in regulating protein expression, we detected downregulation of splicing factors (SF3A1, SF3A2, SF3B1, U2AF1) in various METTL3 KD cell lines (HG3, MEC1, JeKo-1, Mino) at only protein level but not transcription level. These data link METTL3 upregulation with RNA metabolism protein enrichment in CLL. Altogether, our integrated analysis uncovered a novel regulatory axis of METTL3 in CLL biology. We demonstrated that CLL cells have an increased m6A modification and upregulation of METTL3 at the protein level, resulting in translation of RNA metabolism related genes through its reader function by the recognition of m6A modification. Our results collectively suggest METTL3 as a central regulator for mRNA processing in CLL and provide a rationale for targeting METTL3 in this disease. Disclosures Brown: Janssen, Teva: Speakers Bureau; Gilead, Loxo, Sun, Verastem: Research Funding; Abbvie, Acerta, AstraZeneca, Beigene, Invectys, Juno/Celgene, Kite, Morphosys, Novartis, Octapharma, Pharmacyclics, Sunesis, TG Therapeutics, Verastem: Consultancy. Rosen:Seattle Genetics: Consultancy; NeoGenomics: Consultancy; Aileron Therapeutics: Consultancy; Novartis: Consultancy; Pebromene: Consultancy; Celgene: Speakers Bureau; paradigm Medical Communications: Speakers Bureau; Abbvie: Speakers Bureau. Siddiqi:TG Therapeutics: Research Funding; Janssen: Speakers Bureau; Seattle Genetics: Speakers Bureau; Oncternal: Research Funding; BeiGene: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Juno: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Research Funding, Speakers Bureau.

Targeting Aberrant Chromatin in Chronic Lymphocytic Leukemia

Targeting Aberrant Chromatin in Chronic Lymphocytic Leukemia

Epigenome-wide analysis reveals functional modulators of drug sensitivity and post-treatment survival in chronic lymphocytic leukaemia

BackgroundChronic lymphocytic leukaemia (CLL) patients display a highly variable clinical course, with progressive acquisition of drug resistance. We sought to identify aberrant epigenetic traits that are enriched following exposure to treatment that could impact patient response to therapy.MethodsEpigenome-wide analysis of DNA methylation was performed for 20 patients at two timepoints during treatment. The prognostic significance of differentially methylated regions (DMRs) was assessed in independent cohorts of 139 and 163 patients. Their functional role in drug sensitivity was assessed in vitro.ResultsWe identified 490 DMRs following exposure to therapy, of which 31 were CLL-specific and independent of changes occurring in normal B-cell development. Seventeen DMR-associated genes were identified as differentially expressed following treatment in an independent cohort. Methylation of the HOXA4, MAFB and SLCO3A1 DMRs was associated with post-treatment patient survival, with HOXA4 displaying the strongest association. Re-expression of HOXA4 in cell lines and primary CLL cells significantly increased apoptosis in response to treatment with fludarabine, ibrutinib and idelalisib.ConclusionOur study demonstrates enrichment for multiple CLL-specific epigenetic traits in response to chemotherapy that predict patient outcomes, and particularly implicate epigenetic silencing of HOXA4 in reducing the sensitivity of CLL cells to therapy.

DAP Kinase-Related Apoptosis-Inducing Protein Kinase 2 (DRAK2) Is a Key Regulator and Molecular Marker in Chronic Lymphocytic Leukemia.

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the Western World and it is characterized by a marked degree of clinical heterogeneity. An impaired balance between pro- and anti-apoptotic stimuli determines chemorefractoriness and outcome. The low proliferation rate of CLL cells indicates that one of the primary mechanisms involved in disease development may be an apoptotic failure. Here, we study the clinical and functional significance of DRAK2, a novel stress response kinase that plays a critical role in apoptosis, T-cell biology, and B-cell activation in CLL. We have analyzed CLL patient samples and showed that low expression levels of DRAK2 were significantly associated with unfavorable outcome in our CLL cohort. DRAK2 expression levels showed a positive correlation with the expression of DAPK1, and TGFBR1. Consistent with clinical data, the downregulation of DRAK2 in MEC-1 CLL cells strongly increased cell viability and proliferation. Further, our transcriptome data from MEC-1 cells highlighted MAPK, NF-κB, and Akt and as critical signaling hubs upon DRAK2 knockdown. Taken together, our results indicate DRAK2 as a novel marker of CLL survival that plays key regulatory roles in CLL prognosis.

Proliferative Signals in Chronic Lymphocytic Leukemia; What Are We Missing?

Chronic lymphocytic leukemia (CLL) cells cycle between lymphoid tissue sites where they actively proliferate, and the peripheral blood (PB) where they become quiescent. Strong evidence exists for a crucial role of B cell receptor (BCR) triggering, either by (self-)antigen or by receptor auto-engagement in the lymph node (LN) to drive CLL proliferation and provide adhesion. The clinical success of Bruton’s tyrosine kinase (BTK) inhibitors is widely accepted to be based on blockade of the BCR signal. Additional signals in the LN that support CLL survival derive from surrounding cells, such as CD40L-presenting T helper cells, myeloid and stromal cells. It is not quite clear if and to what extent these non-BCR signals contribute to proliferation in situ. In vitro BCR triggering, in contrast, leads to low-level activation and does not result in cell division. Various combinations of non-BCR signals delivered via co-stimulatory receptors, Toll-like receptors (TLRs), and/or soluble cytokines are applied, leading to comparatively modest and short-lived CLL proliferation in vitro. Thus, an unresolved gap exists between the condition in the patient as we now understand it and applicable knowledge that can be harnessed in the laboratory for future therapeutic applications. Even in this era of targeted drugs, CLL remains largely incurable with frequent relapses and emergence of resistance. Therefore, we require better insight into all aspects of CLL growth and potential rewiring of signaling pathways. We aim here to provide an overview of in vivo versus in vitro signals involved in CLL proliferation, point out areas of missing knowledge and suggest future directions for research.

CLL-132: Mutational Status of IGVH in Correlation with Genetic Abnormalities of Patients with Chronic Lymphocytic Leukemia in Macedonia - A Single-Centre Experience

Context B-cell chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease. One of the most important molecular predictors, the immunoglobulin VH gene mutational status, divides CLL into two prognostic groups, where unmutated U-CLL is associated with remarkably worse prognosis than mutated M-CLL. In many studies, multiple recurring chromosomal aberrations appear to be effective prognostic markers in CLL. Objective The aim of the study was first-time evaluation of rearrangement of IG genes and genetic abnormalities in Macedonian CLL patients. Design Prospective study of Macedonian patients with CLL at early and advanced stage of disease in a period of time from January 2011 to January 2019. The median follow-up was 48 months (1-96 months). Setting Mutational status and configuration of IGHV-IGHD-IGHJ rearrangements in 90 treatment-naive CLL patients were analyzed using reverse transcriptase-polymerase chain reaction (RT-PCR) and sequencing methodology. We used multiplex ligation-dependent probe amplification (MLPA) for detection of most common genetic abnormalities. Interventions We introduced prognostic markers like cytogenetic aberrations, and mutational status of immunoglobulin heavy chain in prognostic stratification of Macedonian patients with CLL. Results Our evaluation has shown that 54.7% patients belonged to the U-CLL subset, whereas 45.3% belonged to the M-CLL subset. The most frequently expressed IGHV subgroup was IGHV3 (40%), followed by IGHV4 (29%), IGHV1(27%), and IGHV5 (3%). The most frequent subgroup with 8% were IGHV1-69*13 and IGHV4-34*0. In the IGHD and IGHJ sets, most frequently expressed genes were IGHD3 (59.7%) and IGHJ6(53.1%), respectively. We found that 80% of IGHV1, 65.6% of IGHD3, and 83.3% of IGHJ6 genes were U-CLL (p=0.0005). Frequency of genetic aberrations by MLPA were 13q14 deletion (20%) followed by 11q deletion (14%), then trisomy 12 (13%) and 17p deletion (6.6%), multiple mutations (6.7%), and NOTCH mutation (5.3%). Conclusions Our evaluation of mutational status on IGVH, IGDH, and IGJH genes in Macedonian CLL patients resulted with data that are consubstantial to those from the Mediterranean area. Novel mutations discovered in this study must be validated through large cohort studies and may offer clues to the mechanisms underlying the difference in CLL survival. In the future, therapeutic strategies targeting these genes should be evaluated and considered.

Importance of Crosstalk Between Chronic Lymphocytic Leukemia Cells and the Stromal Microenvironment: Direct Contact, Soluble Factors, and Extracellular Vesicles.

Chronic lymphocytic leukemia (CLL) is caused by the accumulation of malignant B cells due to a defect in apoptosis and the presence of small population of proliferating cells principally in the lymph nodes. The abnormal survival of CLL B cells is explained by a plethora of supportive stimuli produced by the surrounding cells of the microenvironment, including follicular dendritic cells (FDCs), and mesenchymal stromal cells (MSCs). This crosstalk between malignant cells and normal cells can take place directly by cell-to-cell contact (assisted by adhesion molecules such as VLA-4 or CD100), indirectly by soluble factors (chemokines such as CXCL12, CXCL13, or CCL2) interacting with their receptors or by the exchange of material (protein, microRNAs or long non-coding RNAs) via extracellular vesicles. These different communication methods lead to different activation pathways (including BCR and NFκB pathways), gene expression modifications (chemokines, antiapoptotic protein increase, prognostic biomarkers), chemotaxis, homing in lymphoid tissues and survival of leukemic cells. In addition, these interactions are bidirectional, and CLL cells can manipulate the normal surrounding stromal cells in different ways to establish a supportive microenvironment. Here, we review this complex crosstalk between CLL cells and stromal cells, focusing on the different types of interactions, activated pathways, treatment strategies to disrupt this bidirectional communication, and the prognostic impact of these induced modifications.

Unsupervised machine learning and prognostic factors of survival in chronic lymphocytic leukemia.

ObjectiveUnsupervised machine learning approaches hold promise for large-scale clinical data. However, the heterogeneity of clinical data raises new methodological challenges in feature selection, choosing a distance metric that captures biological meaning, and visualization. We hypothesized that clustering could discover prognostic groups from patients with chronic lymphocytic leukemia, a disease that provides biological validation through well-understood outcomes.MethodsTo address this challenge, we applied k-medoids clustering with 10 distance metrics to 2 experiments (“A” and “B”) with mixed clinical features collapsed to binary vectors and visualized with both multidimensional scaling and t-stochastic neighbor embedding. To assess prognostic utility, we performed survival analysis using a Cox proportional hazard model, log-rank test, and Kaplan-Meier curves.ResultsIn both experiments, survival analysis revealed a statistically significant association between clusters and survival outcomes (A: overall survival, P = .0164; B: time from diagnosis to treatment, P = .0039). Multidimensional scaling separated clusters along a gradient mirroring the order of overall survival. Longer survival was associated with mutated immunoglobulin heavy-chain variable region gene (IGHV) status, absent Zap 70 expression, female sex, and younger age.ConclusionsThis approach to mixed-type data handling and selection of distance metric captured well-understood, binary, prognostic markers in chronic lymphocytic leukemia (sex, IGHV mutation status, ZAP70 expression status) with high fidelity.

Survival trend of chronic lymphocytic leukemia and prognostic factors in the United States: An analysis of the National Cancer Database.

e20012 Background: The management of chronic lymphocytic leukemia (CLL) has evolved in the past decade, mainly due to the introduction of novel agents. The outcome of CLL in the general US population and the prognostic factors have not been studied. National Cancer Database (NCDB) includes about 70% of all malignancies in the US and provides a resource to address those questions. Methods: The most recent release of NCDB included CLL cases diagnosed in years 2004-2016. The following variables were included in Cox proportional hazard model for multivariate analysis: age, gender, race, ethnicity, comorbidity score, year of diagnosis, insurance, education, income, facility type, facility volume of CLL and distance to facility. Results: A total of 91309 CLL patients were identified. Median age of diagnosis was 70 years (IQR 61-79). Among the patients, 60.4% were male, 89.4% of patients were White, 7.7% were African American (AA) and 5.8% of patients had either Medicaid or no insurance. At the initial diagnosis, 31.5% of patients were started on treatment and the rest were under active surveillance. Transplant was performed in 0.18% of patients. The OS has improved in years 2010-2016 compared to 2004-2009 with median OS of 90.3 months (95% CI 87.3, .) and 83.6 months (95% CI 82.1-85.0), respectively and 5-year survival rate of 64.2% and 59.9%, respectively (p < 0.0001). Among the 1348 facilities, 16% saw less than 2 CLL patients per year. In the multivariate analysis, the following factors were associated with worse OS: older age, more comorbidities, AA, male gender, East South Central or South Atlantic area, no insurance or Medicaid, lower quartiles of education, and being treated in facilities with lower CLL-patient volume. Conclusions: CLL survival has improved in the past decade. Socioeconomic factors seem to impact survival and with the introduction of newer more expensive therapies, this discrepancy in survival might increase. Furthermore, CLL is a relatively rare malignancy and patients treated at lower-volume facilities had inferior survival. Special attention paid to patients with risk factors might improve outcome. [Table: see text]

NF-κB-p62-NRF2 survival signaling is associated with high ROR1 expression in chronic lymphocytic leukemia.

Progression of chronic lymphocytic leukemia (CLL) and resistance to therapy are affected by tumor microenvironmental factors. One such factor is B-cell activating factor (BAFF), a cytokine that is produced mainly by nurse-like cells (NLC) and enhances CLL cellssurvival and modulates response to therapy. In CLL cells, BAFF activates NF-κB signaling, but how NF-κB supports CLL survival is not entirely clear. In this study we show that BAFF induces accumulation of the signaling and autophagy adaptor p62/SQSTM1 in a manner dependent on NF-κB activation. p62 potentiates mTORC1 signaling and activates NRF2, the master regulator of the anti-oxidant response. We found that expression of NRF2 target genes, such as NAD(P)H quinone oxidoreductase 1 (NQO1), is particularly enriched in CLL cells with high ROR1 surface expression (ROR1Hi). ROR1Hi CLL cells with elevated NQO1 expression exhibit resistance to drugs that induce ROS accumulation, such venetoclax. However, such cells are more sensitive to compound 29h, a pro-drug that only becomes active after being metabolized by NQO1. Accordingly, 29h sensitizes high NQO1 CLL cells to venetoclax. Collectively, our study unravels a previously unknown signaling network through which the NF-κB-p62-NRF2 axis protects ROR1-high CLL cells from ROS-inducing therapeutics.

Highly Potent BTK Degradation Induced By NRX0492 As a Therapeutic Strategy for CLL

B-cell receptor (BCR) signaling plays an essential role in normal B-cell development and is a key driver of proliferation and survival of chronic lymphocytic leukemia (CLL) B cells. BCR signals through BTK to NF-ĸB. Targeted inhibition of BTK with ibrutinib, a first-in-class covalent BTK inhibitor, is highly effective in treating CLL and related B-cell malignancies. However, progressive disease on continuous therapy with ibrutinib has been associated with mutations in BTK and PLCG2. Most patients with acquired resistance and progressive CLL on ibrutinib have mutations in BTK affecting the cysteine at position 481 (C481) to which ibrutinib covalently binds. The common C481S mutation increases IC50 with ibrutinib from low nM to μM concentrations. The emergence of specific BTK mutations in ibrutinib resistant CLL further validate BTK as a valuable therapeutic target in CLL. Therefore, agents that can target C481 mutant BTK are of great interest, and non-covalent BTK inhibitors have entered clinical trials. Here we investigated an alternative approach using a chimeric targeting molecule: NRX0492. NRX0492 combines two molecules: a "hook" that binds BTK with a "harness" that recruits ubiquitin ligases that mediate proteasome-dependent degradation of BTK. In cell line models, NRX0492 induce both wild-type and C481S mutant BTK degradation efficiently and specifically. Here we sought to define the on-target effects of NRX0492 in primary CLL cells in vitro and in vivo and to test NRX0492 against ibrutinib-resistant primary CLL cells. CLL cells were treated at densities of 5 × 106 cells/ml in 24-well plates with NRX0492, ibrutinib, the "hook" moiety devoid of the ubiquitin ligase binding moiety, or DMSO. BTK levels were quantified by Western blotting and flow cytometry. The mean ED50 and ED90 of NRX0492 for BTK degradation at 4 hours was 0.18nM and 0.5nM, respectively. At ED90 concentrations, mean cell viability of cultures treated with NRX0492 was 97.5%, and not different from viability of controls. Incubation at ED50 up to 24 hours also did not induce cell death. A lack of substantial cytotoxic activity with BTK degradation is in line with observations with BTK inhibitors under similar conditions. BTK degradation was achieved rapidly; in time-course experiments of CLL cells treated with 0.2nM NRX0492 the mean half-live of BTK protein was 2.7 hours (range 2.4h-3h), and at 2nM 99% of BTK was degraded within 4 hours. Next, we tested the rate of recovery of BTK expression after drug washout. After 0.2nm NRX0492 treatment for 4 hours, mean BTK levels were 55% of pre-treatment. After washout and continued culture of cells in complete medium for 96 hours, BTK levels were 41% of pre-treatment. In additional experiments with washout of NRX0492 after 4 hours, we found the lowest levels of BTK 48hours post-treatment, indicating a sustained drug effect. There was no significant difference in the efficacy of BTK degradation between CLL samples subdivided by IGHV mutation status or FISH categories. At 0.2nM NRX0492 for 4 hours, mean remaining BTK was 54% in IGHV mutated and 55% in IGHV unmutated samples (P =0.78), and 60% vs 50% for del(13q) vs del(17p) (P =0.18). Next, we studied samples from two patients progressing on ibrutinib with classic C481S mutations at cancer cell fractions of 50% and 84%, respectively. Both patients remained on ibrutinib at the time of sample collection. After 4 hours of treatment with 0.2nM NRX0492, BTK levels were 50% and 15% of DMSO-treated controls, respectively, consistent with degradation of mutant but not ibrutinib bound BTK. Wild-type BTK bound by ibrutinib is not degraded because ibrutinib prevents NRX0492 binding to BTK. In conclusion, we find NRX0492 is highly effective in degrading BTK in CLL cells. NRX0492 is effective at sub nM concentrations with ED50 ~0.2nM and ED90 ~0.5nM in primary CLL cells. Onset of BTK degradation was rapid and sustained for days after drug washout. NRX0492 was effective across CLL risk groups and equally effective in degrading wild-type BTK and C481S-mutant BTK. Studies testing NRX0492 in vivo in PDX models are ongoing and will inform dosing regimens for clinical studies. Disclosures Kelly: Nurix Therapeutics: Employment. Robbins:Nurix Therapeutics: Employment. Tan:Nurix Therapeutics: Employment. Ingallinera:Nurix Therapeutics: Employment. Sands:Nurix Therapeutics: Employment. Baskar:NIH: Patents & Royalties: ROR1 mAb 2A2. Wiestner:Pharmayclics: Research Funding; Acerta: Research Funding; Merck: Research Funding; Nurix: Research Funding.

CD4+ T Cells Sustain Aggressive Chronic Lymphocytic Leukemia through a CD40L-Independent Mechanism

In Chronic Lymphocytic Leukemia (CLL), mature CD5+ B cells accumulate in lymphoid organs such as bone marrow and lymph nodes where they proliferate and expand within localized proliferation centers. In vitro and in vivo data suggest that survival and proliferation of CLL cells within proliferation centers may be also dependent on microenvironmental interactions originating from the surrounding cellular elements (e.g. monocyte-derived nurse-like cells, mesenchymal stromal cells, or CD4+ T lymphocytes), that deliver both membrane-bound and soluble signals to CLL cells. In particular, the role of CD4+ T cells in vivo is less defined and data in animal models are conflicting as they appear to sustain CLL clone expansion and survival through CD40L-CD40 interactions, though in approximately 40% of patients with CLL, aggressive leukemic clones appear to be independent of CD40 stimulation. We aimed at clarifying the role of CD4+ T lymphocytes taking advantage of the Eμ-TCL1 mouse model, which develops a disease that mimics aggressive, human CLL. To this aim, we generated genetically modified Eμ-TCL1 mice lacking either CD4+ T cells (TCL1+/+AB0), CD40 (TCL1+/+CD40-/-), or CD8+ T cells (TCL1+/+TAP-/-). In these mice, disease appearance and progression were monitored in lymphoid organs and blood by flow cytometry and immunohistochemistry analyses. Findings were confirmed by adoptive transfer of leukemic clones into mice either lacking CD4+ T cells, or CD40L, or treated with monoclonal antibodies depleting selected T cell populations, or blocking CD40L-CD40 interactions. Interestingly, we observed that CLL clones did not expand in mice either lacking or depleted of CD4+ T cells, thus confirming that CD4+ T cells are essential for CLL development in Eμ-TCL1 mice. On the contrary, in TCL1+/+TAP-/- mice, lacking CD8+ T cells, disease progression was accelerated, suggesting an anti-tumor activity exerted by this subset of T cells. Specificity of CD4+ T cells was marginal for CLL development, as leukemic clones developed regularly in transgenic mice whose CD4+ T cells had TCR with CLL-unrelated specificities. Similarly, TCL1+/+CD40-/- mice developed frank CLL with no differences compared to controls, as well as leukemic clones expanded when transferred into wild type mice treated with monoclonal antibodies blocking CD40, or into CD40L-/- mice, suggesting a dispensable role for CD40/CD40L stimulation in the development of murine CLL. Analysis of peritoneal fluid, spleen, lymph nodes and bone marrow showed similar CLL development in Eμ-TCL1 and TCL1+/+CD40-/- mice. In conclusion, our data demonstrates that CD8+ and CD4+ T cells exert opposite roles in CLL: CD8+ T cells restrain CLL progression, whereas CD4+ T cells support the expansion of CLL clones in Eμ-TCL1 mice through CD40-indipendent, and apparently non-cognate mechanisms. Further studies are warranted to dissect the nature of the molecules, either soluble or membrane-bound, responsible for the interactions occurring between CD4+ T cells and CLL B cells fueling the onset and expansion of CLL cells. Disclosures Ghia: AbbVie: Consultancy, Honoraria, Research Funding; Acerta/AstraZeneca: Consultancy, Honoraria; ArQule: Consultancy, Honoraria; BeiGene: Consultancy, Honoraria; Dynamo: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Juno/Celgene: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding; Novartis: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy.

A Three-Gene Expression Signature Identifies a Cluster of Patients with Short Survival in Chronic Lymphocytic Leukemia.

Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disorder characterized by its heterogeneous clinical evolution. Despite the discovery of the most frequent cytogenomic drivers of disease during the last decade, new efforts are needed in order to improve prognostication. In this study, we used gene expression data of CLL samples in order to discover novel transcriptomic patterns associated with patient survival. We observed that a 3-gene expression signature composed of SCGB2A1, KLF4, and PPP1R14B differentiate a group of circa 5% of cases with short survival. This effect was independent of the main cytogenetic markers of adverse prognosis. Finally, this finding was reproduced in an independent retrospective cohort. We believe that this small gene expression pattern will be useful for CLL prognostication and its association with CLL response to novel drugs should be explored in the future.

Prognostic role of CD4 T-cell depletion after frontline fludarabine, cyclophosphamide and rituximab in chronic lymphocytic leukaemia

BackgroundEradication of minimal residual disease (MRD), at the end of Fludarabine-Cyclophosphamide-Rituximab (FCR) treatment, is a validated surrogate marker for progression-free and overall survival in chronic lymphocytic leukaemia. But such deep responses are also associated with severe immuno-depletion, leading to infections and the development of secondary cancers.MethodsWe assessed, blood MRD and normal immune cell levels at the end of treatment, in 162 first-line FCR patients, and analysed survival and adverse event.ResultsMultivariate Landmark analysis 3 months after FCR completion identified unmutated IGHV status (HR, 2.03, p = 0.043), the level of MRD reached (intermediate versus low, HR, 2.43, p = 0.002; high versus low, HR, 4.56, p = 0.002) and CD4 > 200/mm3 (HR, 3.30, p < 0.001) as factors independently associated with progression-free survival (PFS); neither CD8 nor NK counts were associated with PFS. The CD4 count was associated with PFS irrespective of IGHV mutational status, but only in patients with detectable MRD (HR, 3.51, p = 0.0004, whereas it had no prognostic impact in MRD < 10− 4 patients: p = 0.6998). We next used a competitive risk model to investigate whether immune cell subsets could be associated with the risk of infection and found no association between CD4, CD8 and NK cells and infection.ConclusionsConsolidation/maintenance trials based on detectable MRD after FCR should investigate CD4 T-cell numbers both as a selection and a response criterion, and consolidation treatments should target B-cell/T-cell interactions.

IgA levels at diagnosis predict for infections, time to treatment, and survival in chronic lymphocytic leukemia

AbstractTo better understand the relationship between baseline immunoglobulin measurements and subsequent clinical outcomes in chronic lymphocytic leukemia (CLL), we performed a retrospective analysis on 660 patients with CLL (72%), monoclonal B-cell lymphocytosis (MBL) (13%), and small lymphocytic lymphoma (SLL) (14%), diagnosed between 2005 and 2014 at CancerCare Manitoba. Of 511 patients who had their first immunoglobulin level determined within 3 months of diagnosis, abnormal (either increased or decreased) immunoglobulin M (IgM), IgG, and IgA values were observed in 58% of patients with CLL, 27% of patients with MBL, and 20% of patients with SLL. Immunoglobulin deviances were similar for MBL and CLL Rai stage 0 and for SLL and Rai stages I and II; for CLL, IgG and IgA abnormalities occurred with increasing frequency with advancing Rai stage. In contrast, the frequency of IgM abnormalities was similar in all patient groups. IgA abnormalities significantly correlated with high β2-microglobulin (B2M) expression, whereas abnormal IgG and IgA levels were associated with the use of IGHV1-69, 3-21, and 3-49 subtypes. Increases in IgG or IgM were commonly associated with the presence of a CLL-type M-band, whereas oligoclonal bands were frequently observed with increased IgA levels. Although abnormal levels of IgG and IgA at diagnosis were independent predictors for future immunoglobulin replacement, only abnormal IgA levels were associated with shorter time to first treatment and overall survival. These findings indicate that both reduced and elevated levels of IgG and IgA at diagnosis are important and independent prognostic markers for infection in CLL, with IgA being more relevant as a marker of disease progression and survival.

Diabetes Mellitus Is Associated with Inferior Prognosis in Patients with Chronic Lymphocytic Leukemia: A Propensity Score-Matched Analysis.

PurposeDiabetes mellitus (DM) is associated with elevated cancer risk and poor survival outcome in malignancies. The objective of this study was to evaluate the prognostic value of preexisting DM in chronic lymphocytic leukemia (CLL).Materials and MethodsSix hundred and thirty-three subjects with newly-diagnosed CLL between 2007 and 2016 were recruited. Propensity score-matched method was performed to balance baseline characteristics and eliminate possible bias. Univariate and multivariate Cox regression analyses screened the independent risk indicators for time-to-first-treatment (TTFT) and cancer-specific survival (CSS) of CLL. Receiver operator characteristic curves and the corresponding areas under the curve assessed the predictive accuracy of CLL–International Prognostic Index (IPI) together with DM.ResultsThe results showed that 111 patients had pre-existing DM. In the propensity-matched cohort, DM was correlated with inferior TTFT and CSS in CLL patients, and it was an independent prognostic factor for both CSS and TTFT. Pre-diabetics also shared undesirable prognostic outcome compared with patients with no diabetic tendency, and a positive association between longer diabetic duration and poorer prognosis of CLL was identified. DM as one additional point to CLL-IPI had larger area under the curve compared with CLL-IPI alone in CSS prediction and could improve the prognostic capacity of CLL-IPI.ConclusionPre-existing DM was found to be a valuable prognostic predictor and could help predict life expectancy and build refined prognostication models for CLL.

PF368 DYSREGULATION OF BACH2 AND FOXP1 GENES IN T AND B CELLS IS MORE PRONOUNCED IN CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS COMPARED TO AGED‐MATCHED HEALTHY DONORS WITH AN IMPACT ON SURVIVAL

Background:We previously investigated BACH2/RPDM1 gene expression in B/T cells from chronic lymphocytic leukemia (CLL) patients and aged‐matched healthy donors (HD) to understand the immunosenescence with aging, which showed that BACH2/PRDM1 are strongly correlated with aging. Recent data show that candidate immune suppressor gene FOXP1 is an important regulator of CLL pathogenesisAims:We further investigated the significance of BACH2, PRDM1, FOXP1 and inhibitory molecule expression in T/B cells from CLL patients.Methods:Peripheral blood mononuclear cells were isolated from untreated CLL patients and age‐matched HD using Lymphoprep density gradient centrifugation. T/B cells were purified by magnetic isolation or FACS sorting. BACH2, PRDM1, FOXP1, PD1, PD‐L1 and TIM3 transcripts were quantified using RT‐qPCR. Nuclear labeling of BACH2/PRDM1 and FOXP1 was accomplished using fixed and permeabilized cells, pre‐labeled for membrane markers and acquired by flow cytometry. Prognostic value of BACH2/PRDM1 and FOXP1 expression in purified CD19+ B cells was analyzed retrospectively in a cohort of CLL patients (n = 270), and correlated with clinical parameters.Results:BACH2 gene expression in HDs is significantly downregulated while PRDM1 gene expression increased in T and B cells according to age groups. BACH2 expression is further reduced in T/B cells from CLL patients compared to age‐matched HDs. Also, PRDM1 is significantly upregulated in T cells from CLL patients but not in leukemic‐B cells. We didn’t observe any age‐related changes in FOXP1 expression. However, among BACH2, FOXP1 and PRDM1 protein expression in lymphocytes from CLL patients, we observe a significant increase of BACH2 and FOXP1 protein expression in CD19+ B cells compared to T cell subsets (n = 21). We analyzed PD1, TIM3 transcript/protein expression in T cells and PD‐L1 expression in B cells to evaluate the exhaustion phenotype associated with CLL and aging. This analysis showed us that PD1 expression is significantly upregulated in CD4+/CD8+ T cells in the older vs younger HDs (n = 60) and also in T cells from CLL patients (n = 41) when compared with age‐matched HDs both at transcript and protein level. High PD‐L1 mRNA and protein expression were also strongly correlated with increased age in HD B cells with a further increase detected in leukemic B cells. In addition, we found a strong inverse correlation between BACH2 and PD1 in CD4+/CD8+ T cells; and between BACH2 and PDL1 in CD19+ B cells. TIM3 transcript/protein expression in T cells was very low in CLL patients and not detected in HD T cells. Prognostic value of BACH2/PRDM1 and FOXP1 expression in purified CD19+ B cells was analysed by RT‐qPCR retrospectively in a cohort of CLL patients, and correlated with clinical stage and IGHV mutation status. In this retrospectively analysed CLL cohort, increased BACH2 expression was correlated with improved treatment‐free survival (p = 0.0352). On the contrary, increased FOXP1 expression was correlated with worsened overall survival of CLL patients in the same cohort (p = 0.0165). However, there was no correlation between BACH2/FOXP1 and Binet stage or IGHV mutation status. We didn’t observe any significant correlations with PRDM1 in terms of survival of CLL patients.Summary/Conclusion:The decrease of BACH2 and increase of FOXP1 in leukemic‐B cells impact on CLL patients’ survival. PD1 and PD‐L1 expression in T/B cells from CLL patients and aged‐matched HDs are significantly correlated with aging‐associated exhaustion of immune cells. The role of BACH2 and FOXP1 in tumor microenvironment is thus further investigated.

AKT/mTORC2 Inhibition Activates FOXO1 Function in CLL Cells Reducing B-Cell Receptor-Mediated Survival.

To determine whether inhibition of mTOR kinase-mediated signaling represents a valid therapeutic approach for chronic lymphocytic leukemia (CLL). Stratification of mTOR activity was carried out in patients with primary CLL samples and an aggressive CLL-like mouse model. The potency of dual mTOR inhibitor AZD8055 to induce apoptosis in primary CLL cells was assessed in the presence/absence of B-cell receptor (BCR) ligation. Furthermore, we addressed the molecular and functional impact of dual mTOR inhibition in combination with BTK inhibitor ibrutinib. Differential regulation of basal mTORC1 activity was observed in poor prognostic CLL samples, with elevated p4EBP1T37/46 and decreased p70S6 kinase activity, suggesting that dual mTORC1/2 inhibitors may exhibit improved response in poor prognostic CLL compared with rapalogs. AZD8055 treatment of primary CLL cells significantly reduced CLL survival in vitro compared with rapamycin, preferentially targeting poor prognostic subsets and overcoming BCR-mediated survival advantages. Furthermore, AZD8055, and clinical analog AZD2014, significantly reduced CLL tumor load in mice. AKT substrate FOXO1, while overexpressed in CLL cells of poor prognostic patients in LN biopsies, peripheral CLL cells, and mouse-derived CLL-like cells, appeared to be inactive. AZD8055 treatment partially reversed FOXO1 inactivation downstream of BCR crosslinking, significantly inhibiting FOXO1T24 phosphorylation in an mTORC2-AKT-dependent manner, to promote FOXO1 nuclear localization, activity, and FOXO1-mediated gene regulation. FOXO1 activity was further significantly enhanced on combining AZD8055 with ibrutinib. Our studies demonstrate that dual mTOR inhibitors show promise as future CLL therapies, particularly in combination with ibrutinib.

Psoas Abscess Due to Mycobacterium avium in A Patient with Chronic Lymphocytic Leukemia－Case Report and Review.

Infections may constitute a serious complication in patients with chronic lymphocytic leukemia (CLL). New treatment agents including obinutuzumab and ibrutinib have improved the progression-free survival in CLL, and data suggest a similar overall infection risk and a limited risk of opportunistic infections when compared to standard chemo-immunotherapy. Nevertheless, cases of opportunistic infections including non-tuberculous mycobacterial (NTM) in CLL patients have recently been published. We present a case of a 74-year old man with extensive prior CLL treatment history, including most recently obinutuzumab. He developed an abscess of the psoas muscle and inguinal lymphadenopathy. An inguinal node biopsy specimen showed infection with Mycobacterium avium, confirmed by broad-spectrum mycobacterial PCR, M. avium-specific PCR, and mycobacterial culture. This case and our literature review suggest that physicians should be aware of opportunistic infections in patients with CLL. Diagnostic differentiation from CLL disease progression, Richter’s transformation to aggressive lymphoma, and secondary malignancy relies on histological and appropriate microbiological studies from biopsy material of affected organs. Infection prophylaxis in CLL should be considered, including vaccinations and intravenous immune globulin replacement.

The Role of Molacular Genetic Examination in Differential Diagnosis and Prognostic Prediction in Patints with B-Cell Chronic Lymphoproliferative Disorders: A Restrospective Study of 1592 Patients

Background: B-cell chronic lymphoproliferative disorders (BCLPD) are a heterogeneous group of mature B-cell malignancies characterized by monoclonal proliferation in the bone marrow (BM) or peripheral blood (PB). The overlapped clinical features and the lack of individual diagnostic markers make diagnosis challenging, especially in patients who have difficulty to get adequate non-BM biopsy specimens or patients manifest as leukemic onset without nodes-involvement. It is necessary to explore novel methods to make precise diagnostic classification and prognostic prediction through simply PB/BM examination.Methods and results: A total of 1592 patients with newly diagnosed BCLPD were enrolled from January 1998 to December 2016, of which chronic lymphocytic leukemia (CLL) accounted for 39%, leukemic marginal zone lymphoma (l-MZL)occupied 13%, and Waldenstrom's macroglobulinemia/ lymphoplasmacytic lymphoma (LPL/WM), leukemic follicular lymphoma (l-FL) and mantle cell lymphoma (l-MCL) were 13%, 9% and 8%, respectively. There are 14% patients failed to fit into any of the categories and remaining unclassified which defined as BCLPDU. The median age at diagnosis was 58 years old. The male/female ratio of all BCLPD patients was 1.84:1. Male predominance was pronounced in WM/LPL, l-MCL and HCL with a M/F ratio of 2.5-2.7, while with balance gender in l-MZL and l-FL.FISH analyses were performed in 1234 patients. 17p and 11q deletion were most common in l-MCL (36% and 17%), while 13q deletion and trisomy 12 were most frequent in CLL (35% and 21%). Patients with 17p deletion showed significantly adverse survival in CLL and l-MCL (p<0.05), but the phenomenon was not found in other types of BCLPD. Instead, complex karyotype showed better predictive capability of worse survival than 17p deletion in patients with l-FL, l-MZL and BCLPDU.A total of 665 patients had been successfully amplified the IGHV-IGHD-IGHJ rearrangements. Based on a cut-off value of 98% homology, the IGHV mutated proportion in patients with l-MCL was 48.6%, which was higher than other BCLPDs, following CLL 33.3% and l-MZL 28.6%, while most of WM and l-FL were unmutated. The most frequent rearrangement in l-MZL were IGHV1-2*01, which was seldom found in other subtypes. Also, DH2-2 and VH3-7 were mainly found in CLL and l-MCL respectively. Besides, we have identified several stereotyped IGH CDR3 which were specific for the certain BCLPD subtype. About 23% unclassified patients could acquire further diagnosis according to the special mutation status, VDJ rearrangements or stereotyped CDR3 sequencing.With a median follow-up of 50.3 months, 522 patients (38.0%) had disease progression or died. Patients with lMCL have a significant worse survival than other entities, with a 3-year overall survival (OS) rate of 58%. Following , patients with WM/LPL had relatively poorer prognosis with a 5-year OS rate of 68.2%, while the prognosis for l-MZL, l-FL and CLL were relatively favourable, with a 5-year OS of 80%.The OS of the B-CLPD had improved over time due to the emergence of immunotherapy and novel (3-year OS improved from 82.1% to 92.2%). The improvement of l-MCL and WM was obvious but not for CLL and l-MZL.Conclusion: Non-BM biopsy specimens are not available for part of BCLPD patients. Overlapped magnification of BM/PB brings on difficulties in differential diagnosis. Besides morphology and immunophenotype, comprehensive analysis of FISH, karyotype, IGHV, MYD88 or BRAF mutation and other molecular examination might contribute to further differential diagnosis and prognostic prediction. Moreover, it might provide advice for the initial time and strategy of treatment. DisclosuresNo relevant conflicts of interest to declare.