ABSTRACT
A large amount of circumstantial evidence has accumulated suggesting that Toll-like receptor (TLR) signals are involved in driving chronic lymphocytic leukemia (CLL) cell proliferation, but direct in vivo evidence for this is still lacking. We have now further addressed this possibility by pharmacologically inhibiting or genetically inactivating the TLR pathway in murine CLL and human Richter syndrome (RS) patient-derived xenograft (PDX) cells. Surprisingly, we show that pharmacologic inhibition of TLR signaling by treatment with an IRAK1/4 inhibitor delays the growth of the transplanted malignant cells in recipient mice, but genetic inactivation of the same pathway by CRISPR/Cas9-mediated disruption of IRAK4 or its proximal adaptor MyD88 has no effect. We further show that treatment with the IRAK1/4 inhibitor results in depletion of macrophages and demonstrate that these cells can support the survival and enhance the proliferation of both murine Eµ-TCL1 leukemia and human RS cells. We also show that genetic disruption of the B-cell receptor (BCR) by CRISPR/Cas9 editing of the immunoglobulin M constant region gene inhibits the growth of human RS-PDX cells in vivo, consistent with our previous finding with murine Eµ-TCL1 leukemia cells. Finally, we show that genetic disruption of IRAK4 does not result in negative selection of human CLL cell lines xenografted in immunodeficient mice. The obtained data suggest that TLR signals are unlikely to represent a major driver of CLL/RS cell proliferation and provide further evidence that signals from macrophages and the BCR promote the growth and survival of CLL and RS cells in vivo.
Subject(s)
Leukemia, Lymphocytic, Chronic, B-Cell , Lymphoma, Large B-Cell, Diffuse , Humans , Mice , Animals , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Interleukin-1 Receptor-Associated Kinases/genetics , Disease Models, Animal , Receptors, Antigen, B-Cell/metabolism , Toll-Like Receptors , Macrophages/metabolismABSTRACT
PURPOSE: Inherited kidney diseases are among the leading causes of kidney failure in children, resulting in increased mortality, high healthcare costs and need for organ transplantation. Next-generation sequencing technologies can help in the diagnosis of rare monogenic conditions, allowing for optimized medical management and therapeutic choices. METHODS: Clinical exome sequencing (CES) was performed on a cohort of 191 pediatric patients from a single institution, followed by Sanger sequencing to confirm identified variants and for family segregation studies. RESULTS: All patients had a clinical diagnosis of kidney disease: the main disease categories were glomerular diseases (32.5%), ciliopathies (20.4%), CAKUT (17.8%), nephrolithiasis (11.5%) and tubular disease (10.5%). 7.3% of patients presented with other conditions. A conclusive genetic test, based on CES and Sanger validation, was obtained in 37.1% of patients. The highest detection rate was obtained for ciliopathies (74.4%), followed by nephrolithiasis (45.5%), tubular diseases (45%), while most glomerular diseases and CAKUT remained undiagnosed. CONCLUSIONS: Results indicate that genetic testing consistently used in the diagnostic workflow of children with chronic kidney disease can (i) confirm clinical diagnosis, (ii) provide early diagnosis in the case of inherited conditions, (iii) find the genetic cause of previously unrecognized diseases and (iv) tailor transplantation programs.
Subject(s)
Ciliopathies , Nephrolithiasis , Renal Insufficiency, Chronic , Child , Humans , Workflow , Genetic TestingABSTRACT
BACKGROUND: Cystic kidney disease is a heterogeneous group of hereditary and non-hereditary pathologic conditions, associated with the development of renal cysts. These conditions may be present both in children and adults. Cysts can even be observed already during the prenatal age, and pediatric patients with cysts need to be clinically monitored. An early clinical and genetic diagnosis is therefore mandatory for optimal patient management. The aim of this study was to perform genetic analyses in patients with echographic evidence of kidney cysts to provide an early molecular diagnosis. METHODS: A cohort of 70 pediatric patients was enrolled and clinically studied at the time of first recruitment and at follow-up. Genetic testing by clinical exome sequencing was performed and a panel of genes responsible for "cystic kidneys" was analyzed to identify causative variants. Sanger validation and segregation studies were exploited for the final classification of the variants and accurate genetic counseling. RESULTS: Data showed that 53/70 of pediatric patients referred with a clinical suspicion of cystic kidney disease presented a causative genetic variant. In a significant proportion of the cohort (24/70), evidence of hyper-echogenic/cystic kidneys was already present in the prenatal period, even in the absence of a positive family history. CONCLUSIONS: This study suggests that cystic kidney disease may develop since the very early stages of life and that screening programs based on ultrasound scans and genetic testing play a critical role in diagnosis, allowing for better clinical management and tailored genetic counseling to the family.
ABSTRACT
Hepatocellular adenomas (HAs) are tumors that can develop under different conditions, including in patients harboring a germline mutation in HNF1A. However, little is known about the pathogenesis of such disease. This work aims to better define what mechanisms lie under the development of this condition. Six HAs were sampled from the liver of a 17-year-old male affected by diabetes and multiple hepatic adenomatosis harboring the heterozygous pathogenic germline variant c.815G>A, p.(Arg272His) in HNF1A, which has a dominant negative effect. All HAs were molecularly characterized. Four of them were shown to harbor a second somatic HNF1A variant and one had a mutation in the ARID1A gene, while no additional somatic changes were found in the remaining HA and normal parenchyma. A transcriptomic profile of the same HA samples was also performed. HNF1A biallelic mutations were associated with the up-regulation of several pathways including the tricarboxylic acid cycle, the metabolism of fatty acids, and mTOR signaling while angiogenesis, endothelial and vascular proliferation, cell migration/adhesion, and immune response were down-regulated. Contrariwise, in the tumor harboring the ARID1A variant, angiogenesis was up-modulated while fatty acid metabolism was down-modulated. Histological analyses confirmed the molecular data. Independently of the second mutation, energetic processes and cholesterol metabolism were up-modulated, while the immune response was down-modulated. This work provides a complete molecular signature of HNF1A-associated HAs, analyzing the association between specific HNF1A variants and the development of HA while identifying potential new therapeutic targets for non-surgical treatment.
Subject(s)
Hepatocyte Nuclear Factor 1-alpha , Liver Neoplasms , Transcriptome , Humans , Hepatocyte Nuclear Factor 1-alpha/genetics , Hepatocyte Nuclear Factor 1-alpha/metabolism , Male , Liver Neoplasms/genetics , Liver Neoplasms/pathology , Liver Neoplasms/metabolism , Adolescent , Adenoma, Liver Cell/genetics , Adenoma, Liver Cell/pathology , Adenoma, Liver Cell/metabolism , Mutation , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Transcription Factors/genetics , Transcription Factors/metabolism , Genomics/methods , DNA-Binding ProteinsABSTRACT
A small subset of cases of chronic lymphocytic leukemia undergoes transformation to diffuse large B-cell lymphoma, Richter syndrome (RS), which is associated with a poor prognosis. Conventional chemotherapy results in limited responses, underlining the need for novel therapeutic strategies. Here, we investigate the ex vivo and in vivo efficacy of the dual phosphatidylinositol 3-kinase-δ/γ (PI3K-δ/γ) inhibitor duvelisib (Duv) and the Bcl-2 inhibitor venetoclax (Ven) using 4 different RS patient-derived xenograft (PDX) models. Ex vivo exposure of RS cells to Duv, Ven, or their combination results in variable apoptotic responses, in line with the expression levels of target proteins. Although RS1316, IP867/17, and RS9737 cells express PI3K-δ, PI3K-γ, and Bcl-2 and respond to the drugs, RS1050 cells, expressing very low levels of PI3K-γ and lacking Bcl-2, are fully resistant. Moreover, the combination of these drugs is more effective than each agent alone. When tested in vivo, RS1316 and IP867/17 show the best tumor growth inhibition responses, with the Duv/Ven combination leading to complete remission at the end of treatment. The synergistic effect of Duv and Ven relies on the crosstalk between PI3K and apoptotic pathways occurring at the GSK3ß level. Indeed, inhibition of PI3K signaling by Duv results in GSK3ß activation, leading to ubiquitination and subsequent degradation of both c-Myc and Mcl-1, making RS cells more sensitive to Bcl-2 inhibition by Ven. This work provides, for the first time, a proof of concept of the efficacy of dual targeting of PI3K-δ/γ and Bcl-2 in RS and providing an opening for a Duv/Ven combination for these patients. Clinical studies in aggressive lymphomas, including RS, are under way. This trial was registered at www.clinicaltrials.gov as #NCT03892044.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Class I Phosphatidylinositol 3-Kinases/antagonists & inhibitors , Class Ib Phosphatidylinositol 3-Kinase , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors , Animals , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Class I Phosphatidylinositol 3-Kinases/metabolism , Female , Humans , Isoquinolines/pharmacology , Leukemia, Lymphocytic, Chronic, B-Cell/metabolism , Male , Mice , Proto-Oncogene Proteins c-bcl-2/metabolism , Purines/pharmacology , Sulfonamides/pharmacology , Xenograft Model Antitumor AssaysABSTRACT
B-cell receptor (BCR) signals play a critical role in the pathogenesis of chronic lymphocytic leukemia (CLL), but their role in regulating CLL cell proliferation has still not been firmly established. Unlike normal B cells, CLL cells do not proliferate in vitro upon engagement of the BCR, suggesting that CLL cell proliferation is regulated by other signals from the microenvironment, such as those provided by Toll-like receptors or T cells. Here, we report that BCR engagement of human and murine CLL cells induces several positive regulators of the cell cycle, but simultaneously induces the negative regulators CDKN1A, CDKN2A, and CDKN2B, which block cell-cycle progression. We further show that introduction of genetic lesions that downregulate these cell-cycle inhibitors, such as inactivating lesions in CDKN2A, CDKN2B, and the CDKN1A regulator TP53, leads to more aggressive disease in a murine in vivo CLL model and spontaneous proliferation in vitro that is BCR dependent but independent of costimulatory signals. Importantly, inactivating lesions in CDKN2A, CDKN2B, and TP53 frequently co-occur in Richter syndrome (RS), and BCR stimulation of human RS cells with such lesions is sufficient to induce proliferation. We also show that tumor cells with combined TP53 and CDKN2A/2B abnormalities remain sensitive to BCR-inhibitor treatment and are synergistically sensitive to the combination of a BCR and cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor both in vitro and in vivo. These data provide evidence that BCR signals are directly involved in driving CLL cell proliferation and reveal a novel mechanism of Richter transformation.
Subject(s)
Cell Transformation, Neoplastic , Cyclin-Dependent Kinase Inhibitor p15 , Cyclin-Dependent Kinase Inhibitor p16 , Leukemia, Lymphocytic, Chronic, B-Cell , Receptors, Antigen, B-Cell , Signal Transduction , Tumor Suppressor Protein p53 , Animals , Cell Line, Tumor , Cell Transformation, Neoplastic/genetics , Cell Transformation, Neoplastic/immunology , Cyclin-Dependent Kinase Inhibitor p15/genetics , Cyclin-Dependent Kinase Inhibitor p15/immunology , Cyclin-Dependent Kinase Inhibitor p16/genetics , Cyclin-Dependent Kinase Inhibitor p16/immunology , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/immunology , Mice , Receptors, Antigen, B-Cell/genetics , Receptors, Antigen, B-Cell/immunology , Signal Transduction/genetics , Signal Transduction/immunology , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/immunologyABSTRACT
Richter syndrome (RS) represents the transformation of chronic lymphocytic leukemia (CLL), typically to an aggressive lymphoma. Treatment options for RS are limited and the disease is often fatal. Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is expressed on CLL cells and other cancers but not on healthy adult tissues, making it an attractive, tumor-specific therapeutic target. VLS-101 is being developed as an antibody-drug conjugate (ADC) for therapy of ROR1-expressing (ROR1+) cancers. VLS-101 comprises UC-961 (a humanized immunoglobulin G1 monoclonal antibody that binds an extracellular epitope of human ROR1), a maleimidocaproyl-valine-citrulline-para-aminobenzoate linker, and the antimicrotubule cytotoxin monomethyl auristatin E (MMAE). VLS-101 binding to ROR1 results in rapid cellular internalization and delivery of MMAE to induce tumor cell death. We studied 4 RS patient-derived xenografts (RS-PDXs) with varying levels of ROR1 expression (11%, 32%, 85%, and 99% of cells). VLS-101 showed no efficacy in the lowest-expressing RS-PDX but induced complete remissions in those with higher levels of ROR1 expression. Responses were maintained during the posttherapy period, particularly after higher VLS-101 doses. In systemic ROR1+ RS-PDXs, VLS-101 dramatically decreased tumor burden in all RS-colonized tissues and significantly prolonged survival. Animals showed no adverse effects or weight loss. Our results confirm ROR1 as a target in RS and demonstrate the therapeutic potential of using an ADC directed toward ROR1 for the treatment of hematological cancers. A phase 1 clinical trial of VLS-101 (NCT03833180) is ongoing in patients with RS and other hematological malignancies.
Subject(s)
Aminobenzoates/pharmacology , Antineoplastic Agents, Immunological/pharmacology , Drug Delivery Systems , Immunoconjugates/pharmacology , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Neoplasm Proteins/antagonists & inhibitors , Oligopeptides/pharmacology , Receptor Tyrosine Kinase-like Orphan Receptors/antagonists & inhibitors , Aminobenzoates/chemistry , Animals , Antineoplastic Agents, Immunological/chemistry , Humans , Immunoconjugates/chemistry , Leukemia, Lymphocytic, Chronic, B-Cell/metabolism , Mice , Mice, Inbred NOD , Mice, Knockout , Mice, SCID , Neoplasm Proteins/metabolism , Oligopeptides/chemistry , Receptor Tyrosine Kinase-like Orphan Receptors/metabolism , Xenograft Model Antitumor AssaysABSTRACT
T-cell immunoreceptor with Ig and ITIM domains (TIGIT) is an inhibitory checkpoint receptor that negatively regulates Tcell responses. CD226 competes with TIGIT for binding to the CD155 ligand, delivering a positive signal to the T cell. Here we studied the expression of TIGIT and CD226 in a cohort of 115 patients with chronic lymphocytic leukemia (CLL) and report expression of TIGIT and CD226 by leukemic cells. By devising a TIGIT/CD226 ratio, we showed that CLL cells favoring TIGIT over CD226 are typical of a more indolent disease, while those favoring CD226 are characterized by a shorter time to first treatment and shorter progression-free survival after first treatment. TIGIT expression was inversely correlated to the B-cell receptor (BCR) signaling capacity, as determined by studying BTK phosphorylation, cell proliferation and interleukin- 10 production. In CLL cells treated with ibrutinib, in which surface IgM and BCR signaling capacity are temporarily increased, TIGIT expression was downmodulated, in line with data indicating transient recovery from anergy. Lastly, cells from patients with Richter syndrome were characterized by high levels of CD226, with low to undetectable TIGIT, in keeping with their high proliferative drive. Together, these data suggest that TIGIT contributes to CLL anergy by downregulating BCR signaling, identifying novel and actionable molecular circuits regulating anergy and modulating CLL cell functions.
Subject(s)
Leukemia, Lymphocytic, Chronic, B-Cell , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/metabolism , Antigens, Differentiation, T-Lymphocyte/metabolism , Cytokines/metabolism , CD8-Positive T-Lymphocytes/metabolism , Receptors, Immunologic/geneticsABSTRACT
Long non-coding RNAs are emerging as essential regulators of gene expression, but their role in normal and neoplastic B cells is still largely uncharacterized. Here, we report on the expression pattern of the LINC00152 in normal B cells and Chronic Lymphocytic Leukemia B cell clones. Higher LINC00152 levels were consistently observed in memory B cell populations when compared to naïve B cells in the normal tissues analyzed [peripheral blood (PB), tonsils, and spleen]. In addition, independent stimulation via Immunoglobulins (IG), CD40, or Toll-like Receptor 9 (TLR9) upregulated LINC00152 in PB B cells. The expression of LINC00152 in a cohort of 107 early stage Binet A CLL patients was highly variable and did not correlate with known prognostic markers or clinical evolution. TLR9 stimulation, but not CD40 or IG challenge, was able to upregulate LINC00152 expression in CLL cells. In addition, LINC00152 silencing in CLL cell lines expressing LINC00152 failed to induce significant cell survival or apoptosis changes. These data suggest that, in normal B cells, the expression of LINC00152 is regulated by immunomodulatory signals, which are only partially effective in CLL cells. However, LINC00152 does not appear to contribute to CLL cell expansion and/or survival in a cohort of newly diagnosed CLL patients.
Subject(s)
Biomarkers, Tumor/metabolism , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Palatine Tonsil/metabolism , RNA, Long Noncoding/metabolism , Spleen/metabolism , Biomarkers, Tumor/genetics , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/metabolism , Prognosis , Prospective Studies , RNA, Long Noncoding/genetics , Survival RateABSTRACT
Despite advances in immunosuppression therapy, acute rejection remains the leading cause of graft dysfunction in lung transplant recipients. Donor-derived cell-free DNA is increasingly being considered as a valuable biomarker of acute rejection in several solid organ transplants. We present a technically improved molecular method based on digital PCR that targets the mismatch between the recipient and donor at the HLA-DRB1 locus. Blood samples collected sequentially post-transplantation from a cohort of lung recipients were used to obtain proof-of-principle for the validity of the assay, correlating results with transbronchial biopsies and lung capacity tests. The results revealed an increase in dd-cfDNA during the first 2 weeks after transplantation related to ischemia-reperfusion injury (6.36 ± 5.36%, p < 0.0001). In the absence of complications, donor DNA levels stabilized, while increasing again during acute rejection episodes (7.81 ± 12.7%, p < 0.0001). Respiratory tract infections were also involved in the release of dd-cfDNA (9.14 ± 15.59%, p = 0.0004), with a positive correlation with C-reactive protein levels. Overall, the dd-cfDNA percentages were inversely correlated with the lung function values measured by spirometry. These results confirm the value of dd-cfDNA determination during post-transplant follow-up to monitor acute rejection in lung recipients, achieved using a rapid and inexpensive approach based on the HLA mismatch between donor and recipient.
Subject(s)
Cell-Free Nucleic Acids , Transplant Recipients , Cost-Benefit Analysis , Graft Rejection/etiology , Humans , Lung , Tissue DonorsABSTRACT
OPINION STATEMENT: In the last 10-15 years, the way to treat cancers has dramatically changed towards precision medicine approaches. These treatment options are mainly based on selective targeting against signaling pathways critical for or detrimentally activated in cancer cells in cancer cells, as well as exploiting molecules that are specifically expressed on neoplastic cells, also known as tumor-associated antigens. These considerations hold true also in the hematological field where a plethora of novel targeted agents have reached patients' bedside, significantly improving clinical responses. Chronic lymphocytic leukemia (CLL) is an example of how targeted therapies, such as BTK, PI3K, or Bcl-2 inhibitors as well as anti-CD20 antibodies, have improved patients' management, even when adopted as frontline treatment. However, these advancements do not apply to Richter's syndrome (RS), the transformation of CLL into a very aggressive and fatal lymphoma, occurring in 2-10% of patients. RS is usually a fast-growing lymphoma of the diffuse large B cell or the Hodgkin's variant, with a dismal prognosis. Despite advancements in depicting and understanding the genetic background of RS and its pathogenesis, no significant clinical results have been registered. In the last couple of years, several studies have started to investigate the impact of novel drugs or drug combinations and some of them have opened for clinical trials, currently in phase I or II, whose results will be soon available. This review will present an overview of current and most recent therapeutic options in RS, discussing also how results coming from xenograft models may help in designing and identifying novel treatment opportunities to overcome the lack of effective therapies.
Subject(s)
Antineoplastic Agents , Leukemia, Lymphocytic, Chronic, B-Cell , Lymphoma, Large B-Cell, Diffuse , Antineoplastic Agents/therapeutic use , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Leukemia, Lymphocytic, Chronic, B-Cell/etiology , Lymphoma, Large B-Cell, Diffuse/pathology , PrognosisABSTRACT
Tumor immunosuppression is a major cause for treatment failure and disease relapse, both in solid tumors and leukemia. Local hypoxia is among the conditions that cause immunosuppression, acting at least in part through the upregulation of extracellular adenosine levels, which potently suppress T cell responses and skew macrophages towards an M2 phenotype. Hence, there is intense investigation to identify drugs that target this axis. By using the TCL1 adoptive transfer CLL mouse model, we show that adenosine production and signaling are upregulated in the hypoxic lymphoid niches, where intense colonization of leukemic cells occurs. This leads to a progressive remodeling of the immune system towards tolerance, with expansion of T regulatory cells (Tregs), loss of CD8+ T cell cytotoxicity and differentiation of murine macrophages towards the patrolling (M2-like) subset. In vivo administration of SCH58261, an inhibitor the A2A adenosine receptor, re-awakens T cell responses, while limiting Tregs expansion, and re-polarizes monocytes towards the inflammatory (M1-like) phenotype. These results show for the first time the in vivo contribution of adenosine signaling to immune tolerance in CLL, and the translational implication of drugs interrupting this pathway. Although the effects of SCH58261 on leukemic cells are limited, interfering with adenosine signaling may represent an appealing strategy for combination-based therapeutic approaches.
Subject(s)
Leukemia, Lymphocytic, Chronic, B-Cell , Animals , Disease Models, Animal , Immune Tolerance , Immunosuppression Therapy , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Mice , Receptors, Purinergic P1ABSTRACT
Representing the major cause of morbidity and mortality for chronic lymphocytic leukemia (CLL) patients, immunosuppression is a common feature of the disease. Effectors of the innate and the adaptive immune response show marked dysfunction and skewing towards the generation of a tolerant environment that favors disease expansion. Major deregulations are found in the T lymphocyte compartment, with inhibition of CD8+ cytotoxic and CD4+ activated effector T cells, replaced by exhausted and more tolerogenic subsets. Likewise, differentiation of monocytes towards a suppressive M2-like phenotype is induced at the expense of pro-inflammatory sub-populations. Thanks to their B-regulatory phenotype, leukemic cells play a central role in driving immunosuppression, progressively inhibiting immune responses. A number of signaling cascades triggered by soluble mediators and cell-cell contacts contribute to immunomodulation in CLL, fostered also by local environmental conditions, such as hypoxia and derived metabolic acidosis. Specifically, molecular pathways modulating T-cell activity in CLL, spanning from the best known cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death 1 (PD-1) to the emerging T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT)/CD155 axes, are attracting increasing research interest and therapeutic relevance also in the CLL field. On the other hand, in the microenvironment, the B cell receptor (BCR), which is undoubtedly the master regulator of leukemic cell behavior, plays an important role in orchestrating immune responses, as well. Lastly, local conditions of hypoxia, typical of the lymphoid niche, have major effects both on CLL cells and on non-leukemic immune cells, partly mediated through adenosine signaling, for which novel specific inhibitors are currently under development. In summary, this review will provide an overview of the molecular and microenvironmental mechanisms that modify innate and adaptive immune responses of CLL patients, focusing attention on those that may have therapeutic implications.
Subject(s)
Adaptive Immunity/immunology , Immunity, Innate/immunology , Immunomodulation , Leukemia, Lymphocytic, Chronic, B-Cell/immunology , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Tumor Microenvironment/immunology , Animals , HumansABSTRACT
Targeting adenosine triphosphate (ATP) metabolism and adenosinergic signaling in cancer is gaining momentum, as increasing evidence is showing their relevance in tumor immunology and biology. Chronic lymphocytic leukemia (CLL) results from the expansion of a population of mature B cells that progressively occupies the bone marrow (BM), the blood, and peripheral lymphoid organs. Notwithstanding significant progress in the treatment of these patients, the cure remains an unmet clinical need, suggesting that novel drugs or drug combinations are needed. A unique feature of CLL is its reliance on micro-environmental signals for proliferation and cell survival. We and others have shown that the lymphoid niche, an area of intense interactions between leukemic and bystander non-tumor cells, is a typically hypoxic environment. Here adenosine is generated by leukemic cells, as well as by cells of myeloid origin, acting through autocrine and paracrine mechanisms, ultimately affecting tumor growth, limiting drug responses, and skewing the immune cells towards a tolerant phenotype. Hence, understanding the mechanisms through which this complex network of enzymes, receptors, and metabolites functions in CLL, will pave the way to the use of pharmacological agents targeting the system, which, in combination with drugs targeting leukemic cells, may get us one step closer to curing these patients.
Subject(s)
Adenosine Triphosphate/metabolism , Adenosine/metabolism , Leukemia, Lymphocytic, Chronic, B-Cell/immunology , Molecular Targeted Therapy/methods , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Gene Regulatory Networks/drug effects , Humans , Hypoxia , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/metabolism , Signal Transduction/drug effects , Stem Cell Niche , Tumor MicroenvironmentABSTRACT
Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme in nicotinamide adenine dinucleotide biosynthesis. In the extracellular compartment, it exhibits cytokine-/adipokinelike properties, suggesting that it stands at the crossroad between metabolism and inflammation. Here we show that both intracellular and extracellular NAMPT levels are increased in cells and plasma of chronic lymphocytic leukemia (CLL) patients. The extracellular form (eNAMPT) is produced by CLL lymphocytes upon B-cell receptor, Toll-like receptor, and nuclear factor κB (NF-κB) signaling pathway activation. eNAMPT is important for differentiation of resting monocytes, polarizing them toward tumor-supporting M2 macrophages. These cells express high levels of CD163, CD206, and indoleamine 2,3-dioxygenase and secrete immunosuppressive (interleukin [IL] 10, CC chemokine ligand 18) and tumor-promoting (IL-6, IL-8) cytokines. NAMPT-primed M2 macrophages activate extracellular-regulated kinase 1/2, signal transducer and activator of transcription 3, and NF-κB signaling; promote leukemic cell survival; and reduce T-cell responses. These effects are independent of the enzymatic activity of NAMPT, as inferred from the use of an enzymatically inactive mutant. Overall, these results reveal that eNAMPT is a critical element in the induction of an immunosuppressive and tumor-promoting microenvironment of CLL.
Subject(s)
Leukemia, Lymphocytic, Chronic, B-Cell/enzymology , Macrophages/metabolism , Nicotinamide Phosphoribosyltransferase/metabolism , Aged , Antigens, CD/metabolism , Antigens, Differentiation, Myelomonocytic/metabolism , B-Lymphocytes/cytology , Blood Donors , Cell Differentiation , Cell Proliferation , Cell Survival , Enzyme-Linked Immunosorbent Assay , Female , Humans , Indoleamine-Pyrrole 2,3,-Dioxygenase/metabolism , Interleukin-10/metabolism , Lectins, C-Type/metabolism , Macrophages/cytology , Male , Mannose Receptor , Mannose-Binding Lectins/metabolism , Microscopy, Confocal , Monocytes/cytology , Mutation , NF-kappa B/metabolism , Phagocytosis , Receptors, Cell Surface/metabolism , STAT3 Transcription Factor/metabolismABSTRACT
IT-901 is a novel and selective NF-κB inhibitor with promising activity in pre-clinical models. Here we show that treatment of chronic lymphocytic leukemia cells (CLL) with IT-901 effectively interrupts NF-κB transcriptional activity. CLL cells exposed to the drug display elevated mitochondrial reactive oxygen species, which damage mitochondria, limit oxidative phosphorylation and ATP production, and activate intrinsic apoptosis. Inhibition of NF-κB signaling in stromal and myeloid cells, both tumor-supportive elements, fails to induce apoptosis, but impairs NF-κB-driven expression of molecules involved in cell-cell contacts and immune responses, essential elements in creating a pro-leukemic niche. The consequence is that accessory cells do not protect CLL cells from IT-901-induced apoptosis. In this context, IT-901 shows synergistic activity with ibrutinib, arguing in favor of combination strategies. IT-901 is also effective in primary cells from patients with Richter syndrome (RS). Its anti-tumor properties are confirmed in xenograft models of CLL and in RS patient-derived xenografts, with documented NF-κB inhibition and significant reduction of tumor burden. Together, these results provide pre-clinical proof of principle for IT-901 as a potential new drug in CLL and RS.
Subject(s)
Antineoplastic Agents/pharmacology , Energy Metabolism/drug effects , Leukemia, Lymphocytic, Chronic, B-Cell/metabolism , NF-kappa B/antagonists & inhibitors , Adenine/analogs & derivatives , Animals , Antineoplastic Agents/therapeutic use , Apoptosis/drug effects , Cell Line, Tumor , Cell Survival , Disease Models, Animal , Drug Synergism , Gene Silencing , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Mice , Mitochondria/drug effects , Mitochondria/metabolism , Molecular Targeted Therapy , NF-kappa B/genetics , NF-kappa B/metabolism , Piperidines , Pyrazoles/pharmacology , Pyrimidines/pharmacology , Reactive Oxygen Species/metabolism , Signal Transduction/drug effects , Xenograft Model Antitumor AssaysABSTRACT
The genetic lesions identified to date do not fully recapitulate the molecular pathogenesis of chronic lymphocytic leukemia (CLL) and do not entirely explain the development of severe complications such as chemorefractoriness. In the present study, BIRC3, a negative regulator of noncanonical NF-κB signaling, was investigated in different CLL clinical phases. BIRC3 lesions were absent in monoclonal B-cell lymphocytosis (0 of 63) and were rare in CLL at diagnosis (13 of 306, 4%). Conversely, BIRC3 disruption selectively affected 12 of 49 (24%) fludarabine-refractory CLL cases by inactivating mutations and/or gene deletions that distributed in a mutually exclusive fashion with TP53 abnormalities. In contrast to fludarabine-refractory CLL, progressive but fludarabine-sensitive patients were consistently devoid of BIRC3 abnormalities, suggesting that BIRC3 genetic lesions associate specifically with a chemorefractory phenotype. By actuarial analysis in newly diagnosed CLL (n = 306), BIRC3 disruption identified patients with a poor outcome similar to that associated with TP53 abnormalities and exerted a prognostic role that was independent of widely accepted clinical and genetic risk factors. Consistent with the role of BIRC3 as a negative regulator of NF-κB, biochemical studies revealed the presence of constitutive noncanonical NF-κB activation in fludarabine-refractory CLL patients harboring molecular lesions of BIRC3. These data identify BIRC3 disruption as a recurrent genetic lesion of high-risk CLL devoid of TP53 abnormalities.
Subject(s)
Antineoplastic Agents/therapeutic use , Drug Resistance, Neoplasm/genetics , Inhibitor of Apoptosis Proteins/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Tumor Suppressor Protein p53/genetics , Vidarabine/analogs & derivatives , Aged , Baculoviral IAP Repeat-Containing 3 Protein , Blotting, Western , DNA Mutational Analysis , Female , Humans , In Situ Hybridization, Fluorescence , Inhibitor of Apoptosis Proteins/metabolism , Kaplan-Meier Estimate , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Leukemia, Lymphocytic, Chronic, B-Cell/mortality , Male , Middle Aged , NF-kappa B/metabolism , Prognosis , Proportional Hazards Models , Reverse Transcriptase Polymerase Chain Reaction , Ubiquitin-Protein Ligases , Vidarabine/therapeutic useABSTRACT
Circulating cell-free DNA (cfDNA) refers to small fragments of DNA molecules released after programmed cell death and necrosis in several body fluids such as blood, saliva, urine, and cerebrospinal fluid. The discovery of cfDNA has revolutionized the field of non-invasive diagnostics in the oncologic field, in prenatal testing, and in organ transplantation. Despite the potential of cfDNA and the solid results published in the recent literature, several challenges remain, represented by a low abundance, a need for highly sensitive assays, and analytical issues. In this review, the main technical advances in cfDNA analysis are presented and discussed, with a comprehensive examination of the current available methodologies applied in each field. Considering the potential advantages of cfDNA, this biomarker is increasing its consensus among clinicians, as it allows us to monitor patients' conditions in an easy and non-invasive way, offering a more personalized care. Nevertheless, cfDNA analysis is still considered a diagnostic marker to be further validated, and very few centers are implementing its analysis in routine diagnostics. As technical improvements are enhancing the performances of cfDNA analysis, its application will transversally improve patients' quality of life.