The cytokine TNF can trigger highly proinflammatory RIPK1-dependent cell death. Here, we show that the two adapter proteins, TANK and AZI2, suppress TNF-induced cell death by regulating the activation of TBK1 kinase. Mice lacking either TANK or AZI2 do not show an overt phenotype. Conversely, animals deficient in both adapters are born in a sub-Mendelian ratio and suffer from severe multi-organ inflammation, excessive antibody production, male sterility, and early mortality, which can be rescued by TNFR1 deficiency and significantly improved by expressing a kinase-dead form of RIPK1. Mechanistically, TANK and AZI2 both recruit TBK1 to the TNF receptor signaling complex, but with distinct kinetics due to interaction with different complex components. While TANK binds directly to the adapter NEMO, AZI2 is recruited later via deubiquitinase A20. In summary, our data show that TANK and AZI2 cooperatively sustain TBK1 activity during different stages of TNF receptor assembly to protect against autoinflammation.
- MeSH
- Adaptor Proteins, Signal Transducing * metabolism genetics MeSH
- Cell Death MeSH
- Endopeptidases MeSH
- Intracellular Signaling Peptides and Proteins metabolism genetics MeSH
- Humans MeSH
- Mice, Inbred C57BL MeSH
- Mice, Knockout * MeSH
- Mice MeSH
- Protein Serine-Threonine Kinases * metabolism genetics MeSH
- Receptors, Tumor Necrosis Factor, Type I * metabolism genetics MeSH
- Receptor-Interacting Protein Serine-Threonine Kinases * metabolism genetics MeSH
- Signal Transduction MeSH
- Tumor Necrosis Factor-alpha * metabolism MeSH
- Tumor Necrosis Factor alpha-Induced Protein 3 metabolism genetics MeSH
- Inflammation metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: Mantle cell lymphoma (MCL) is a chronically relapsing malignancy with deregulated cell cycle progression. We analyzed efficacy, mode of action, and predictive markers of susceptibility to palbociclib, an approved CDK 4/6 inhibitor, and its combination with venetoclax, a BCL2 inhibitor. METHODS: A panel of nine MCL cell lines were used for in vitro experiments. Four patient derived xenografts (PDX) obtained from patients with chemotherapy and ibrutinib-refractory MCL were used for in vivo proof-of-concept studies. Changes of the mitochondrial membrane potential, energy-metabolic pathways, AKT activity, and pro-apoptotic priming of MCL cells were evaluated by JC-1 staining, Seahorse XF analyser, genetically encoded fluorescent AKT reporter, and BH3 profiling, respectively. MCL clones with gene knockout or transgenic (over)expression of CDKN2A, MYC, CDK4, and RB1 were used to estimate impact of these aberrations on sensitivity to palbociclib, and venetoclax. RESULTS: Co-targeting MCL cells with palbociclib and venetoclax induced cytotoxic synergy in vitro and in vivo. Molecular mechanisms responsible for the observed synthetic lethality comprised palbociclib-mediated downregulation of anti-apoptotic MCL1, increased levels of proapoptotic BIM bound on both BCL2, and BCL-XL and increased pro-apoptotic priming of MCL cells mediated by BCL2-independent mechanisms, predominantly palbociclib-triggered metabolic and mitochondrial stress. Loss of RB1 resulted in palbociclib resistance, while deletion of CDKN2A or overexpression of CDK4, and MYC genes did not change sensitivity to palbociclib. CONCLUSIONS: Our data strongly support investigation of the chemotherapy-free palbociclib and venetoclax combination as an innovative treatment strategy for post-ibrutinib MCL patients without RB1 deletion.
Patients with myelodysplastic neoplasms (MDS) are classified according to the risk of acute myeloid leukemia transformation. Some lower-risk MDS patients (LR-MDS) progress rapidly despite expected good prognosis. Using diagnostic samples, we aimed to uncover the mechanisms of this accelerated progression at the transcriptome level. RNAseq was performed on CD34+ ribodepleted RNA samples from 53 LR-MDS patients without accelerated progression (stMDS) and 8 who progressed within 20 months (prMDS); 845 genes were differentially expressed (ІlogFCІ > 1, FDR < 0.01) between these groups. stMDS CD34+ cells exhibited transcriptional signatures of actively cycling, megakaryocyte/erythrocyte lineage-primed progenitors, with upregulation of cell cycle checkpoints and stress pathways, which presumably form a tumor-suppressing barrier. Conversely, cell cycle, DNA damage response (DDR) and energy metabolism-related pathways were downregulated in prMDS samples, whereas cell adhesion processes were upregulated. Also, prMDS samples showed high levels of aberrant splicing and global lncRNA expression that may contribute to the attenuation of DDR pathways. We observed overexpression of multiple oncogenes and diminished differentiation in prMDS; the expression of ZEB1 and NEK3, genes not previously associated with MDS prognosis, might serve as potential biomarkers for LR-MDS progression. Our 19-gene DDR signature showed a significant predictive power for LR-MDS progression. In validation samples (stMDS = 3, prMDS = 4), the key markers and signatures retained their significance. Collectively, accelerated progression of LR-MDS appears to be associated with transcriptome patterns of a quiescent-like cell state, reduced lineage differentiation and suppressed DDR, inherent to CD34+ cells. The attenuation of DDR-related gene-expression signature may refine risk assessment in LR-MDS patients.
- MeSH
- Cell Adhesion MeSH
- Cell Cycle MeSH
- NIMA-Related Kinases genetics metabolism MeSH
- Humans MeSH
- Myelodysplastic Syndromes * genetics MeSH
- Neoplasms * MeSH
- DNA Repair MeSH
- Transcriptome MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Overall, reactive oxygen species (ROS) signalling significantly contributes to initiation and mo-dulation of multiple regulated cell death (RCD) pathways. Lately, more information has become available about RCD modalities of erythrocytes, including the role of ROS. ROS accumulation has therefore been increasingly recognized as a critical factor involved in eryptosis (apoptosis of erythrocytes) and erythro-necroptosis (necroptosis of erythrocytes). Eryptosis is a Ca2+-dependent apoptosis-like RCD of erythrocytes that occurs in response to oxidative stress, hyperosmolarity, ATP depletion, and a wide range of xenobiotics. Moreover, eryptosis seems to be involved in the pathogenesis of multiple human diseases and pathological processes. Several studies have reported that erythrocytes can also undergo necroptosis, a lytic RIPK1/RIPK3/MLKL-mediated RCD. As an example, erythronecroptosis can occur in response to CD59-specific pore-forming toxins. We have systematically summarized available studies regarding the involvement of ROS and oxidative stress in these two distinct RCDs of erythrocytes. We have focused specifically on cellular signalling pathways involved in ROS-mediated cell death decisions in erythrocytes. Furthermore, we have summarized dysregulation of related erythrocytic antioxidant defence systems. The general concept of the ROS role in eryptotic and necroptotic cell death pathways in erythrocytes seems to be established. However, further studies are required to uncover the complex role of ROS in the crosstalk and interplay between the survival and RCDs of erythrocytes.
- MeSH
- Eryptosis * physiology MeSH
- Erythrocytes metabolism MeSH
- Humans MeSH
- Oxidation-Reduction MeSH
- Reactive Oxygen Species metabolism MeSH
- Calcium metabolism MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Mantle cell lymphoma (MCL) is a subtype of B-cell lymphoma with a large number of recurrent cytogenetic/molecular aberrations. Approximately 5-10% of patients do not respond to frontline immunochemotherapy. Despite many useful prognostic indexes, a reliable marker of chemoresistance is not available. We evaluated the prognostic impact of seven recurrent gene aberrations including tumor suppressor protein P53 (TP53) and cyclin dependent kinase inhibitor 2A (CDKN2A) in the cohort of 126 newly diagnosed consecutive MCL patients with bone marrow involvement ≥5% using fluorescent in-situ hybridization (FISH) and next-generation sequencing (NGS). In contrast to TP53, no pathologic mutations of CDKN2A were detected by NGS. CDKN2A deletions were found exclusively in the context of other gene aberrations suggesting it represents a later event (after translocation t(11;14) and aberrations of TP53, or ataxia telangiectasia mutated (ATM)). Concurrent deletion of CDKN2A and aberration of TP53 (deletion and/or mutation) represented the most significant predictor of short EFS (median 3 months) and OS (median 10 months). Concurrent aberration of TP53 and CDKN2A is a new, simple, and relevant index of chemoresistance in MCL. Patients with concurrent aberration of TP53 and CDKN2A should be offered innovative anti-lymphoma therapy and upfront consolidation with allogeneic stem cell transplantation.
- Publication type
- Journal Article MeSH
IL-17 mediates immune protection from fungi and bacteria, as well as it promotes autoimmune pathologies. However, the regulation of the signal transduction from the IL-17 receptor (IL-17R) remained elusive. We developed a novel mass spectrometry-based approach to identify components of the IL-17R complex followed by analysis of their roles using reverse genetics. Besides the identification of linear ubiquitin chain assembly complex (LUBAC) as an important signal transducing component of IL-17R, we established that IL-17 signaling is regulated by a robust negative feedback loop mediated by TBK1 and IKKε. These kinases terminate IL-17 signaling by phosphorylating the adaptor ACT1 leading to the release of the essential ubiquitin ligase TRAF6 from the complex. NEMO recruits both kinases to the IL-17R complex, documenting that NEMO has an unprecedented negative function in IL-17 signaling, distinct from its role in NF-κB activation. Our study provides a comprehensive view of the molecular events of the IL-17 signal transduction and its regulation.
- MeSH
- Adaptor Proteins, Signal Transducing genetics metabolism MeSH
- HEK293 Cells MeSH
- HeLa Cells MeSH
- I-kappa B Kinase genetics metabolism MeSH
- Humans MeSH
- Protein Serine-Threonine Kinases genetics metabolism MeSH
- Receptors, Interleukin-17 genetics metabolism MeSH
- Signal Transduction * MeSH
- Feedback, Physiological * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The ability to inhibit mitochondrial apoptosis is a hallmark of B-cell non-Hodgkin lymphomas (B-NHL). Activation of mitochondrial apoptosis is tightly controlled by members of B-cell leukemia/lymphoma-2 (BCL-2) family proteins via protein-protein interactions. Altering the balance between anti-apoptotic and pro-apoptotic BCL-2 proteins leads to apoptosis evasion and extended survival of malignant cells. The pro-survival BCL-2 proteins: B-cell leukemia/lymphoma-2 (BCL-2/BCL2), myeloid cell leukemia-1 (MCL-1/MCL1) and B-cell lymphoma-extra large (BCL-XL/BCL2L1) are frequently (over)expressed in B-NHL, which plays a crucial role in lymphoma pathogenesis, disease progression, and drug resistance. The efforts to develop inhibitors of anti-apoptotic BCL-2 proteins have been underway for several decades and molecules targeting anti-apoptotic BCL-2 proteins are in various stages of clinical testing. Venetoclax is a highly specific BCL-2 inhibitor, which has been approved by the US Food and Drug Agency (FDA) for the treatment of patients with chronic lymphocytic leukemia (CLL) and is in advanced clinical testing in other types of B-NHL. In this review, we summarize the biology of BCL-2 proteins and the mechanisms of how these proteins are deregulated in distinct B-NHL subtypes. We describe the mechanism of action of BH3-mimetics and the status of their clinical development in B-NHL. Finally, we summarize the mechanisms of sensitivity/resistance to venetoclax.
- Publication type
- Journal Article MeSH
- Review MeSH
- MeSH
- Survival Analysis MeSH
- Transplantation, Autologous MeSH
- Progression-Free Survival MeSH
- Adult MeSH
- Remission Induction methods MeSH
- Middle Aged MeSH
- Humans MeSH
- Lymphoma, Mantle-Cell mortality therapy MeSH
- Antineoplastic Combined Chemotherapy Protocols therapeutic use MeSH
- Rituximab therapeutic use MeSH
- Aged MeSH
- Hematopoietic Stem Cell Transplantation MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Letter MeSH
- Clinical Trial MeSH
- Research Support, Non-U.S. Gov't MeSH
