ABSTRACT
DDX3X is a ubiquitously expressed RNA helicase involved in multiple stages of RNA biogenesis. DDX3X is frequently mutated in Burkitt lymphoma, but the functional basis for this is unknown. Here, we show that loss-of-function DDX3X mutations are also enriched in MYC-translocated diffuse large B cell lymphoma and reveal functional cooperation between mutant DDX3X and MYC. DDX3X promotes the translation of mRNA encoding components of the core translational machinery, thereby driving global protein synthesis. Loss-of-function DDX3X mutations moderate MYC-driven global protein synthesis, thereby buffering MYC-induced proteotoxic stress during early lymphomagenesis. Established lymphoma cells restore full protein synthetic capacity by aberrant expression of DDX3Y, a Y chromosome homolog, the expression of which is normally restricted to the testis. These findings show that DDX3X loss of function can buffer MYC-driven proteotoxic stress and highlight the capacity of male B cell lymphomas to then compensate for this loss by ectopic DDX3Y expression.
Subject(s)
B-Lymphocytes/enzymology , DEAD-box RNA Helicases/metabolism , Lymphoma, B-Cell/enzymology , Minor Histocompatibility Antigens/metabolism , Neoplasm Proteins/biosynthesis , Proto-Oncogene Proteins c-myc/metabolism , Adolescent , Adult , Aged , Aged, 80 and over , Animals , B-Lymphocytes/pathology , Cell Line, Tumor , Child , Child, Preschool , DEAD-box RNA Helicases/genetics , Endoplasmic Reticulum Stress , Female , Gene Expression Regulation, Enzymologic , Gene Expression Regulation, Neoplastic , Humans , Loss of Function Mutation , Lymphoma, B-Cell/genetics , Lymphoma, B-Cell/pathology , Male , Mice, Transgenic , Middle Aged , Minor Histocompatibility Antigens/genetics , Neoplasm Proteins/genetics , Protein Biosynthesis , Proteome , Proteostasis , Proto-Oncogene Proteins c-myc/genetics , Young AdultABSTRACT
Burkitt lymphoma (BL) accounts for almost two-thirds of all B-cell non-Hodgkin lymphoma (B-NHL) in children and adolescents and is characterised by a MYC translocation and rapid cell turnover. Intensive chemotherapeutic regimens have been developed in recent decades, including the lymphomes malins B (LMB) protocol, which have resulted in a survival rate in excess of 90%. Recent clinical trials have focused on immunochemotherapy, with the addition of rituximab to chemotherapeutic backbones, showing encouraging results. Despite these advances, relapse and refractory disease occurs in up to 10% of patients and salvage options for these carry a dismal prognosis. Efforts to better understand the molecular and functional characteristics driving relapse and refractory disease may help improve this prognosis. This study has established a paediatric BL patient-derived xenograft (PDX) resource which captures and maintains tumour heterogeneity, may be used to better characterise tumours and identify cell populations responsible for therapy resistance.
Subject(s)
Burkitt Lymphoma/pathology , Animals , Burkitt Lymphoma/genetics , Burkitt Lymphoma/therapy , Child , Disease Models, Animal , Female , Gene Expression Regulation, Neoplastic , Heterografts/pathology , Humans , Male , Mice , Neoplasm Transplantation , Tumor Cells, CulturedABSTRACT
Anaplastic large cell lymphoma (ALCL) is a T-cell malignancy predominantly driven by a hyperactive anaplastic lymphoma kinase (ALK) fusion protein. ALK inhibitors, such as crizotinib, provide alternatives to standard chemotherapy with reduced toxicity and side effects. Children with lymphomas driven by nucleophosmin 1 (NPM1)-ALK fusion proteins achieved an objective response rate to ALK inhibition therapy of 54% to 90% in clinical trials; however, a subset of patients progressed within the first 3 months of treatment. The mechanism for the development of ALK inhibitor resistance is unknown. Through genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) activation and knockout screens in ALCL cell lines, combined with RNA sequencing data derived from ALK inhibitor-relapsed patient tumors, we show that resistance to ALK inhibition by crizotinib in ALCL can be driven by aberrant upregulation of interleukin 10 receptor subunit alpha (IL10RA). Elevated IL10RA expression rewires the STAT3 signaling pathway, bypassing otherwise critical phosphorylation by NPM1-ALK. IL-10RA expression does not correlate with response to standard chemotherapy in pediatric patients, suggesting that a combination of crizotinib and chemotherapy could prevent ALK inhibitor resistance-specific relapse.
Subject(s)
Antineoplastic Agents/pharmacology , Crizotinib/pharmacology , Drug Resistance, Neoplasm/genetics , Interleukin-10 Receptor alpha Subunit/genetics , Lymphoma, Large-Cell, Anaplastic/genetics , Protein Kinase Inhibitors/pharmacology , Protein-Tyrosine Kinases/genetics , Antineoplastic Agents/therapeutic use , CRISPR-Cas Systems , Cell Line , Crizotinib/therapeutic use , Dose-Response Relationship, Drug , Gene Editing , Gene Expression , Humans , Immunohistochemistry , Interleukin-10 Receptor alpha Subunit/metabolism , Lymphoma, Large-Cell, Anaplastic/drug therapy , Lymphoma, Large-Cell, Anaplastic/metabolism , Lymphoma, Large-Cell, Anaplastic/pathology , Models, Biological , Nucleophosmin , Protein Kinase Inhibitors/therapeutic use , Protein-Tyrosine Kinases/metabolism , STAT3 Transcription Factor/metabolism , Signal Transduction/drug effectsABSTRACT
Deficiency in mevalonate kinase (MVK) causes systemic inflammation. However, the molecular mechanisms linking the mevalonate pathway to inflammation remain obscure. Geranylgeranyl pyrophosphate, a non-sterol intermediate of the mevalonate pathway, is the substrate for protein geranylgeranylation, a protein post-translational modification that is catalyzed by protein geranylgeranyl transferase I (GGTase I). Pyrin is an innate immune sensor that forms an active inflammasome in response to bacterial toxins. Mutations in MEFV (encoding human PYRIN) result in autoinflammatory familial Mediterranean fever syndrome. We found that protein geranylgeranylation enabled Toll-like receptor (TLR)-induced activation of phosphatidylinositol-3-OH kinase (PI(3)K) by promoting the interaction between the small GTPase Kras and the PI(3)K catalytic subunit p110δ. Macrophages that were deficient in GGTase I or p110δ exhibited constitutive release of interleukin 1ß that was dependent on MEFV but independent of the NLRP3, AIM2 and NLRC4 inflammasomes. In the absence of protein geranylgeranylation, compromised PI(3)K activity allows an unchecked TLR-induced inflammatory responses and constitutive activation of the Pyrin inflammasome.
Subject(s)
Alkyl and Aryl Transferases/metabolism , Familial Mediterranean Fever/metabolism , Inflammasomes/metabolism , Macrophages/physiology , Mutation/genetics , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Pyrin/genetics , Alkyl and Aryl Transferases/genetics , Animals , Cells, Cultured , Familial Mediterranean Fever/genetics , Humans , Immunity, Innate , Interleukin-1beta/metabolism , Mice, Inbred C57BL , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/metabolism , Phosphotransferases (Alcohol Group Acceptor)/genetics , Polyisoprenyl Phosphates/metabolism , Protein Processing, Post-Translational , Signal Transduction , Toll-Like Receptors/metabolismABSTRACT
Multiple clinical trials have shown that the 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors known as statins have anti-inflammatory effects. However, the underlying molecular mechanism remains unclear. The proinflammatory cytokine interleukin-1ß (IL-1ß) is synthesized as a non-active precursor. The 31-kDa pro-IL-1ß is processed into the 17-kDa active form by caspase-1-activating inflammasomes. Here, we report a novel signaling pathway induced by statins, which leads to processing of pro-IL-1ß into an intermediate 28-kDa form. This statin-induced IL-1ß processing is independent of caspase-1- activating inflammasomes. The 28-kDa form of IL-1ß cannot activate interleukin-1 receptor-1 (IL1R1) to signal inflammatory responses. Instead, it interferes with mature IL-1ß signaling through IL-1R1 and therefore may dampen inflammatory responses initiated by mature IL-1ß. These results may provide new clues to explain the anti-inflammatory effects of statins.