CD73-generated extracellular adenosine in chronic lymphocytic leukemia creates local conditions counteracting drug-induced cell death

Abstract Extracellular adenosine (ADO), generated from ATP or ADP through the concerted action of the ectoenzymes CD39 and CD73, elicits autocrine and paracrine effects mediated by type 1 purinergic receptors. We have tested whether the expression of CD39 and CD73 by chronic lymphocytic leukemia (CLL) cells activates an adenosinergic axis affecting growth and survival. By immunohistochemistry, CD39 is widely expressed in CLL lymph nodes, whereas CD73 is restricted to proliferation centers. CD73 expression is highest on Ki-67+ CLL cells, adjacent to T lymphocytes, and is further localized to perivascular areas. CD39+/CD73+ CLL cells generate ADO from ADP in a time- and concentration-dependen…

Active Akt signaling triggers CLL toward Richter transformation via overactivation of Notch1

Abstract Richter’s transformation (RT) is an aggressive lymphoma that occurs upon progression from chronic lymphocytic leukemia (CLL). Transformation has been associated with genetic aberrations in the CLL phase involving TP53, CDKN2A, MYC, and NOTCH1; however, a significant proportion of RT cases lack CLL phase–associated events. Here, we report that high levels of AKT phosphorylation occur both in high-risk CLL patients harboring TP53 and NOTCH1 mutations as well as in patients with RT. Genetic overactivation of Akt in the murine Eµ-TCL1 CLL mouse model resulted in CLL transformation to RT with significantly reduced survival and an aggressive lymphoma phenotype. In the absence of recurren…

2.35 CD73-Generated Extracellular Adenosine Creates Microenvironmental Conditions Favoring Growth and Survival of Chronic Lymphocytic Leukemia Cells

Abstract Abstract 621 CD39 (ecto-nucleoside-triphosphate-diphosphohydrolase-1) and CD73 (5'-nucleotidase) are surface enzymes with extracellular catalytic sites. CD39 hydrolyses ATP/ADP to AMP, which is then converted to adenosine (ADO) by CD73. Once ADO is released in the extracellular milieu, it may re-enter the cell or engage different types of purinergic receptors, eliciting potent autocrine and paracrine cytoprotective, anti-inflammatory and immunosuppressive effects. Several lines of evidence suggest that the tumor microenvironment is marked by increased turnover of extracellular nucleotides and nucleosides, as well as by upregulation of ecto-enzymes that dismantle them. These alterat…

Secondary resistance to the PI3K inhibitor copanlisib in marginal zone lymphoma

PI3K kinase has a prominent role in the B-cell receptor signaling. Copanlisib, a pan-PI3K inhibitor with predominant selectivity to PI3Kα and PI3Kδ, is Food and Drug Administration (FDA) approved for the treatment of patients with relapsed or refractory follicular lymphoma, and it is currently under clinical development in other indolent lymphomas including marginal zone lymphoma (MZL). However some patients might eventually relapse because of acquired resistance and so a better understanding of resistance mechanisms is needed. Thus we generated MZL cell lines resistant to copanlisib which could help to design improved therapies

Assessment of the 4-factor score: Retrospective analysis of 586 CLL patients receiving ibrutinib. A campus CLL study

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Survival risk score for real-life relapsed/refractory chronic lymphocytic leukemia patients receiving ibrutinib. A campus CLL study

Pooled analysis of who surgical safety checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients incl…

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the Globa…

Global economic burden of unmet surgical need for appendicitis

Abstract Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capita…

A variant of the LRP4 gene affects the risk of chronic lymphocytic leukaemia transformation to Richter syndrome

Richter syndrome (RS) represents the transformation of chronic lymphocytic leukaemia (CLL) to aggressive lymphoma. Risk factors of CLL transformation to RS are only partly known. We explored the role of the host genetic background as a risk factor for RS occurrence. Forty-five single nucleotide polimorphisms (SNPs) known to be relevant for CLL prognosis were genotyped in a consecutive cohort of 331 CLL, of which 21 had transformed to RS. After correcting for multiple testing and adjusting for previously reported RS risk factors, the LRP4 rs2306029 TT variant genotype was the sole SNP independently associated with a higher risk of RS transformation (Hazard Ratio: 4·17; P = 0·001; q = 0·047).…

Angiopoietin-2 plasma dosage predicts time to first treatment and overall survival in chronic lymphocytic leukemia.

Abstract The clinical relevance of angiopoietin-2 (Ang2) in chronic lymphocytic leukemia (CLL) was previously suggested by the association between high Ang2, and shorter progression-free survival reported in small series of patients. Here, we evaluated Ang2 glycoprotein levels in plasma samples collected from a multicentric cohort of CLL patients (n = 316) using an enzyme-linked immunosorbent assay method, and we investigated its prognostic role in relation to time to first treatment (TTFT) and overall survival. Based on a cutoff equal to 2459 pg/mL, we divided our cohort in 2 subsets (high and low Ang2) composing 100 (31.6%) and 216 (68.4%) patients, respectively. High Ang2 was predictive …

Host Genetic Background and Risk of Richter Syndrome: The Genotype of LRP4 Is An Independent Predictor of Chronic Lymphocytic Leukemia Transformation to Aggressive Lymphoma.

Abstract Abstract 2340 Poster Board II-317 Richter syndrome (RS) represents the transformation of chronic lymphocytic leukemia (CLL) to aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). Mechanisms and risk factors of CLL transformation to RS are known only in part. This study aimed at exploring the role of the host genetic background in RS transformation and was based on a consecutive series of 331 CLL, of which 21 had transformed to RS (all clonally related to the CLL clone). Twenty eight additional cases of clonally related RS were also collected for validation purposes. Using an educated guess approach, SNPs were selected according to the following criteria: i) re…

Abstract PO-46: Mechanisms of resistance to the PI3K inhibitor copanlisib in marginal zone lymphoma

Abstract Background: PI3Kδ is expressed in B cells and has a central role in the B-cell receptor signaling. Copanlisib is a highly selective PI3Kδ and PI3Kα inhibitor, and it is currently under clinical development in indolent lymphomas including marginal zone lymphoma (MZL). Copanlisib is Food and Drug Administration (FDA) approved for the treatment of patients with relapsed or refractory follicular lymphoma. Nevertheless, a subset of patients can eventually relapse due to acquired resistance. A better understanding of resistance mechanisms could help to design improved therapies; hence, we generated MZL cell lines resistant to copanlisib. Materials and Methods: Cells were kept on copanlis…

A novel role of the CX3CR1/CX3CL1 system in the cross-talk between chronic lymphocytic leukemia cells and tumor microenvironment

Several chemokines/chemokine receptors such as CCR7, CXCR4 and CXCR5 attract chronic lymphocytic leukemia (CLL) cells to specific microenvironments. Here we have investigated whether the CX(3)CR1/CX(3)CL1 axis is involved in the interaction of CLL with their microenvironment. CLL cells from 52 patients expressed surface CX(3)CR1 and CX(3)CL1 and released constitutively soluble CX(3)CL1. One third of these were attracted in vitro by soluble CX(3)CL1. CX(3)CL1-induced phosphorylation of PI3K, Erk1/2, p38, Akt and Src was involved in induction of CLL chemotaxis. Leukemic B cells upregulated CXCR4 upon incubation with CX(3)CL1 and this was paralleled by increased chemotaxis to CXCL12. Akt phosp…

CD49d Expression Identifies a Chronic Lymphocytic Leukemia (CLL) Subset with High Levels of Circulating CD34 +Cells Co-Expressing Endothelial Cell Markers.

Abstract Abstract 2329 Poster Board II-306 Introduction: In chronic lymphocytic leukemia (CLL), CD49d, often in association with CD38, has been shown to mark a disease subset with poor prognosis. Functionally, both molecules act as counter-receptors for surface structures (i.e. VCAM-1/CD106 and CD31) usually expressed by the endothelial/stromal component of tumor micro-environment. We have recently identified a micro-environmental circuitry which involves CD38 triggering, and eventually determines an enrichment of the VCAM-1/CD106-expressing endothelial component detected in the context of CLL infiltrates found in bone marrow biopsies. Data was also provided that CD49d/VCAM-1 interactions a…

CD38/CD31, the CCL3 and CCL4 chemokines, and CD49d/vascular cell adhesion molecule-1 are interchained by sequential events sustaining chronic lymphocytic leukemia cell survival.

AbstractCD38 and CD49d are associated negative prognosticators in chronic lymphocytic leukemia (CLL). Despite evidence that both molecules are involved in interactions occurring between CLL and normal cells in the context of CLL-involved tissues, a functional link is still missing. Using gene expression profiles comparing CD38+CD49d+ versus CD38−CD49d− CLL cells, we showed overexpression of the CCL3 and CCL4 chemokines in cells from the former group. These chemokines were also up-regulated by CD38 signals in CLL; moreover, CCL3 was expressed by CLL cells from bone marrow biopsies (BMB) of CD38+CD49d+ but not CD38−CD49d− cases. High levels of CCR1 and, to a lesser extent, CCR5, the receptors…