Mucosa-associated Lymphoid Tissue Lymphoma Translocation Research Articles

MALT1 serves as a biomarker for estimating disease risk of lupus nephritis: a prospective case-control study.

BackgroundMucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) regulates immune/inflammation response and kidney injury, indicating that it might participate in the lupus nephritis (LN) pathology. The present study sought to investigate the utility of MALT1 serving as an indicator of severity and inflammation biomarker in LN.MethodsIn total, 30 LN patients and 30 non-LN systemic lupus erythematosus (SLE) patients were recruited, and blood MALT1 expression was detected using reverse transcription-quantitative polymerase. Besides, the SLE disease activity index was calculated for all subjects to assess disease activity.ResultsMALT1 was more increased in LN patients than non-LN SLE patients {2.26 [interquartile range (IQR): 1.38–3.54] vs. 1.04 (IQR, 0.60–1.62); P<0.001}. Additionally, the multivariate logistic regression model analysis indicated that higher MALT1 [odds ratio (OR): 3.097, 95% CI: 1.292–7.425, P=0.011] and higher serum creatinine (Scr) (OR: 1.055, 95% CI: 1.012–1.099, P=0.011) were independently related to an elevated risk of LN. The MALT1 and Scr-based nomogram exhibited a good value in estimating LN risk with an area under the curve (AUC) of 0.873 (95%CI: 0.787–0.960). MALT1 was highest in LN patients with class IV (accompanied by V or not), followed by class V and class III (accompanied by V or not) patients, and lowest in class II patients (P=0.046). MALT1 was positively linked to the LN activity index (rs=0.370, P=0.044); however, while it was positively associated with the LN chronicity index, the level did not reach statistical significance (rs=0.341, P=0.066). MALT1 was positively linked to 24 h proteinuria (rs=0.473, P=0.008), Scr (rs=0.378, P=0.039), and C-reactive protein (CRP) (rs=0.410, P=0.025) in LN patients.ConclusionsMALT1 might serve as a useful biomarker for estimating the disease risk in LN patients; however, future large-sample size studies need to be conducted to validate our findings.

The Gab2–MALT1 axis regulates thromboinflammation and deep vein thrombosis

AbstractDeep vein thrombosis (DVT) is the third most common cause of cardiovascular mortality. Several studies suggest that DVT occurs at the intersection of dysregulated inflammation and coagulation upon activation of inflammasome and secretion of interleukin 1β (IL-1β) in restricted venous flow conditions. Our recent studies showed a signaling adapter protein, Gab2 (Grb2-associated binder 2), plays a crucial role in propagating inflammatory signaling triggered by IL-1β and other inflammatory mediators in endothelial cells. The present study shows that Gab2 facilitates the assembly of the CBM (CARMA3 [CARD recruited membrane-associated guanylate kinase protein 3]–BCL-10 [B-cell lymphoma 10]–MALT1 [mucosa-associated lymphoid tissue lymphoma translocation protein 1]) signalosome, which mediates the activation of Rho and NF-κB in endothelial cells. Gene silencing of Gab2 or MALT1, the effector signaling molecule in the CBM signalosome, or pharmacological inhibition of MALT1 with a specific inhibitor, mepazine, significantly reduced IL-1β–induced Rho-dependent exocytosis of P-selectin and von Willebrand factor (VWF) and the subsequent adhesion of neutrophils to endothelial cells. MALT1 inhibition also reduced IL-1β–induced NF-κB–dependent expression of tissue factor and vascular cell adhesion molecule 1. Consistent with the in vitro data, Gab2 deficiency or pharmacological inhibition of MALT1 suppressed the accumulation of monocytes and neutrophils at the injury site and attenuated venous thrombosis induced by the inferior vena cava ligation-induced stenosis or stasis in mice. Overall, our data reveal a previously unrecognized role of the Gab2–MALT1 axis in thromboinflammation. Targeting the Gab2–MALT1 axis with MALT1 inhibitors may become an effective strategy to treat DVT by suppressing thromboinflammation without inducing bleeding complications.

Mucosa‐associated lymphoid tissue lymphoma translocation protein 1 in rheumatoid arthritis: Longitudinal change after treatment and correlation with treatment efficacy of tumor necrosis factor inhibitors

BackgroundMucosa‐associated lymphoid tissue lymphoma translocation protein 1 (MALT1) correlates with treatment outcomes in inflammatory bowel disease and rheumatoid arthritis (RA). This study aimed to further evaluate the MALT1 longitudinal change and its relationship with tumor necrosis factor inhibitors (TNFi) response in RA patients.MethodsSeventy‐one RA patients receiving TNFi [etanercept (n = 42) or adalimumab (n = 29)] were enrolled. MALT1 was detected by RT‐qPCR in peripheral blood samples of RA patients before treatment (W0), at week (W)4, W12, and W24 after treatment. RA patients were divided into response/non‐response, remission/non‐remission patients according to their treatment outcome at W24. Meanwhile, MALT1 was also detected by RT‐qPCR in 30 osteoarthritis patients and 30 healthy controls (HCs).ResultsMucosa‐associated lymphoid tissue lymphoma translocation protein 1 was elevated in RA patients compared with HCs (Z=−6.392, p < 0.001) and osteoarthritis patients (Z = −5.020, p < 0.001). In RA patients, MALT1 was positively correlated with C‐reactive protein (rs = 0.347, p = 0.003), but not other clinical characteristics, treatment history, or current TNFi category. Meanwhile, MALT1 decreased from W0 to W12 in total RA patients (x2 = 86.455, p < 0.001), etanercept subgroup (x2 = 46.636, p < 0.001), and adalimumab subgroup (x2 = 41.291, p < 0.001). Moreover, MALT1 at W24 (p = 0.012) was decreased in response patients compared with non‐response patients; MALT1 at W12 (p = 0.027) and W24 (p = 0.010) were reduced in remission patients than non‐remission patients. In etanercept subgroup, MALT1 at W24 (p = 0.013) was decreased in response patients compared with non‐response patients. In adalimumab subgroup, MALT1 at W24 (p = 0.015) was lower in remission patients than non‐remission patients.ConclusionMucosa‐associated lymphoid tissue lymphoma translocation protein 1 reduction after treatment is associated with response and remission to TNFi in RA patients.

MALT1 in asthma children: A potential biomarker for monitoring exacerbation risk and Th1/Th2 imbalance-mediated inflammation.

BackgroundMucosa‐associated lymphoid tissue lymphoma translocation protein 1 (MALT1) participates in the immune‐related allergic response and inflammation flare, while its clinical role in asthma children is still unknown. Herein, this study aimed to investigate MALT1 expression, and its correlation with exacerbation risk, T helper (Th)1, Th2 cells (and their secreted cytokines), as well as inflammatory cytokines in asthma children.MethodsSixty children with asthma exacerbation and 60 children with remission asthma were enrolled in this study; then their blood MALT1, Th1, Th2 cells, tumor necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6), interferon‐gamma (IFN‐γ), and interleukin‐4 (IL‐4) were detected. Besides, blood MALT1 in another 20 health controls was also determined.ResultsMucosa‐associated lymphoid tissue lymphoma translocation protein 1 was highest in children with asthma exacerbation, followed by children with remission asthma, and lowest in health controls (p < 0.001). MALT1 could distinguish children with asthma exacerbation from children with remission asthma (area under the curve (AUC): 0.757, 95% CI: 0.670–0.843). In children with asthma exacerbation, MALT1 was negatively linked with IFN‐γ (p = 0.002) and Th1 cells (p = 0.050), but positively related to Th2 cells (p = 0.027) and exhibited a positive correlation trend (without statistical significance) with IL‐4 (p = 0.066); meanwhile, MALT1 was positively correlated with exacerbation severity (p = 0.010) and TNF‐α (p = 0.003), but not linked with IL‐6 (p = 0.096). In children with remission asthma, MALT1 only was negatively associated with Th1 cells (p = 0.023), but positively linked with TNF‐α (p = 0.023).ConclusionMucosa‐associated lymphoid tissue lymphoma translocation protein 1 serves as a potential biomarker for monitoring exacerbation risk and Th1/Th2 imbalance‐mediated inflammation of asthma children.

Targeting MALT1 Suppresses the Malignant Progression of Colorectal Cancer via miR-375/miR-365a-3p/NF-κB Axis.

Colorectal cancer (CRC) is a malignant tumor with the second highest morbidity and the third highest mortality in the world, while the therapeutic options of targeted agents remain limited. Here, mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1), known as the upstream of the NF-κB signaling pathway, was identified to be highly upregulated in CRC tumors and cell lines. Furthermore, the downregulation of MALT1 or inhibition of its proteolytic function by MI-2 suppressed the cell proliferation and migration of CRC cells. In vivo, suppressing the MALT1 expression or its proteasome activity effectively reduced the size of the subcutaneous tumor in nude mice. Mechanistically, miR-375 and miR-365a-3p were identified to inhibit NF-κB activation via targeting MALT1. Overall, our results highlight that a novel regulatory axis, miRNA-MALT1-NF-κB, plays a vital role in the progression of CRC and provides novel and hopeful therapeutic targets for clinical treatment.

Potential role of MALT1 as a candidate biomarker of disease surveillance and treatment response prediction in inflammatory bowel disease patients.

BackgroundMucosa‐associated lymphoid tissue lymphoma translocation protein 1 (MALT1) regulates adaptive and innate immune responses in several inflammatory disease. However, clinical involvement of MALT1 in inflammatory bowel disease (IBD) patients remains unclear. Hence, this study was intended to investigate the correlation of blood MALT1 with disease activity, inflammation indexes as well as treatment response of IBD patients.MethodsBlood MALT1 expression in 100 IBD patients [including 25 active (A)‐Crohn's disease (CD) patients, 25 remission (R)‐CD patients, 25 A‐ulcerative colitis (UC) patients, and 25 R‐UC patients] and 25 health controls (HCs) was detected by reverse transcription‐quantitative polymerase chain reaction; besides, serum tumor necrosis factor‐alpha (TNF‐α) and interleukin‐17A (IL‐17A) in IBD patients were detected by enzyme‐linked immunosorbent assay.ResultsMALT1 was increased in A‐UC patients than in R‐UC patients (p = 0.038) and in HCs (p < 0.001), and also elevated in A‐CD patients than in R‐CD patients (p = 0.048) and in HCs (p < 0.001). MALT1 was positively related to C‐reactive protein (CRP, p = 0.011), TNF‐α (p = 0.036), IL‐17A (p = 0.023), and Mayo score (p = 0.005) in A‐UC patients, CRP (p = 0.017), erythrocyte sedimentation rate (p = 0.033), TNF‐α (p = 0.004), and Crohn's disease activity index score (p = 0.028) in A‐CD patients. But MALT1 was not correlated with either inflammation indexes or disease activity score in R‐UC and R‐CD patients. MALT1 gradually declined from baseline to W12 in A‐UC and A‐CD patients (both p < 0.001). Moreover, MALT1 at W4 (p = 0.031) and W12 (p = 0.003) in A‐UC patients as well as MALT1 at W12 (p = 0.008) in A‐CD patients associated with clinical response.ConclusionMALT1 serves as a potential biomarker for disease surveillance and treatment response prediction of IBD patients.

Combined detection of lymphocyte clonality and MALT1 translocations in bronchoalveolar lavage fluid for diagnosing pulmonary lymphomas

Diagnosis of pulmonary lymphoma using small tissue samples is difficult and often requires surgical procedures; thus, a less invasive sampling method is desirable. We previously showed that pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma can be diagnosed by detecting MALT lymphoma translocation gene 1 (MALT1) translocations in bronchoalveolar lavage fluid (BALF) cells. Analysis of B-cell clonality based on immunoglobulin heavy chain (IGH) gene rearrangements was also reportedly useful for diagnosing pulmonary lymphoma. The aim of this prospective multicenter study was to evaluate the yet unknown diagnostic potential of combined detection of MALT1 translocations and clonality using BALF. We analyzed B- and T-cell clonality based on IGH and T-cell receptor (TCR) rearrangements together with MALT1 translocations using BALF of patients with clinically suspected pulmonary lymphomas. In total, 39 patients were evaluated and categorized into three groups: B-cell lymphoma, lymphoproliferative disorders, and other diseases. IGH rearrangement detection for B-cell lymphoma diagnosis exhibited sensitivity and specificity of 88.9% and 90.0%, respectively. TCR rearrangements were not observed in patients with B-cell lymphomas. The presence of IGH rearrangements together with the absence of TCR rearrangements indicated 96.0% specificity for the diagnosis of B-cell lymphoma. The sensitivity and specificity of MALT1 translocations for diagnosing MALT lymphoma were 28.6% and 100%, respectively. The combined detection of lymphocyte clonality and MALT1 translocations using BALF is suitable for screening and diagnosis of B-cell lymphomas. Analysis of specific genes such as MALT1 should improve the precision of B-cell lymphoma diagnosis.

Blood MALT1, Th1, and Th17 cells are dysregulated, inter-correlated, and correlated with disease activity in rheumatoid arthritis patients; meanwhile, MALT1 decline during therapy relates to treatment outcome.

ObjectiveMucosa‐associated lymphoid tissue lymphoma translocation protein 1 (MALT1) participates in inflammatory and autoimmune diseases via activating various signaling pathways and promoting the differentiation of T‐helper (Th) 1 and Th17 cells; however, it is rarely reported in rheumatoid arthritis (RA). This study aimed to assess the correlation of MALT1 with Th1 and Th17 cells and evaluate its potential as a biomarker for evaluating disease activity and treatment outcomes in RA patients.MethodsThis study enrolled 139 RA patients and 45 health controls (HCs); then, blood MALT1, Th1, and Th17 cells were determined. For RA patients only, blood MALT1 at week (W) 6 and W12 after treatment was also detected. Additionally, clinical response and remission of RA patients were assessed at W12.ResultsMALT1 (p < 0.001), Th1 (p = 0.011), and Th17 (p < 0.001) cells were all increased in RA patients than HCs; meanwhile, increased MALT1 was associated with elevated Th1 (p = 0.003) and Th17 (p < 0.001) cells in RA patients. Besides, MALT1, Th1, and Th17 cells were positively correlated with parts of disease activity indexes in RA patients (all p < 0.050). In addition, MALT1 was gradually declined from W0 to W12 (p < 0.001) in RA patients. Specifically, MALT1 at W6 and W12 was lower in response patients than no response patients (both p < 0.010), also in remission patients than no remission patients (both p < 0.050).ConclusionMALT1, Th1, and Th17 cells are dysregulated, inter‐correlated, and correlated with disease activity in RA patients; meanwhile, the decline of MALT1 expression can partly reflect RA treatment response and remission.

Allosteric Inhibition of MALT1 Is Efficacious in a Model of Chronic Graft-Versus-Host Disease and Modulates Immunometabolic Activation

IntroductionGraft-versus-host disease (GVHD) is a severe complication of allogeneic hematopoietic cell transplantation. In its chronic form, GVHD causes prolonged post-transplant morbidity and significant mortality. There is a paucity of approved therapies and the current standard of care results in incomplete responses that leave significant unmet need for novel agents. Mucosa-associated lymphoid tissue lymphoma translocation protein-1 (MALT1) is a bi-functional protein that acts as a signal-propagation scaffold and protease for selective innate and adaptive immune cell receptor signaling. The established link between MALT1 and receptor-mediated activation of multiple immune cell types involved in cGVHD argues for it as a therapeutic target for cGVHD. Furthermore, we have identified MALT1 signaling to be important in linking receptor-initiated signaling to changes in cellular metabolism necessary for immune cell effector function and propose that immunometabolic profiling of immune cells from cGVHD patients may provide novel biomarkers of both disease pathophysiology and associated MALT1 activity.Methods, Results, ConclusionTo assess MALT1 as a novel drug target in cGVHD, we first characterized the effectiveness of allosteric inhibition on protease, scaffolding, and metabolic activity in primary human T cells. MALT1 inhibition of T-cell receptor (TCR) activated CD4 + T cells reduced protease activity by >90% and scaffolding activity by ∼50%, downstream of TCR activation. Consistent with disruption of the TCR signaling cascade, MALT1 inhibition reduced T H1 and T H17 cytokines, and the T FH cytokine IL-21 in a concentration dependent manner. B-cell receptor (BCR) driven proliferation of human B cells and C-type-lectin receptor and immune complex driven cytokine production from human macrophages were also inhibited.We next tested MALT1 inhibition in a sclerodermatous rodent model of cGVHD (scGVHD). Allogeneic bone marrow and splenocytes from LP/J donor mice were transferred to irradiated C57BL/6 recipient mice. Starting on day 21 after transfer, animals were dosed orally once daily with a MALT1 inhibitor, or twice daily with the JAK1/2 inhibitor ruxolitinib as a comparator. All animals were monitored daily for weight change, survival and GVHD score. On a modified scGVHD scoring scale, animals treated with a MALT1 inhibitor had significantly more progression-free survival throughout the study than vehicle or ruxolitinib-treated animals. No differential effect was observed on body weight and overall survival. MALT1 inhibitor treatment, but not ruxolitinib, reduced frequencies of splenic T FH cells and germinal center B cells compared with vehicle-treated mice. Importantly, MALT1 inhibition had no effect on the frequency or numbers of splenic regulatory T cells. Additionally, a delayed-type hypersensitivity (DTH) response was abrogated with MALT1 inhibition, showing that T-cell-driven responses in the skin, an important target tissue in cGVHD, can be abrogated with MALT1 blockade.Given recent studies implicating MALT1 activity as a link between immunoreceptor signaling and activation-dependent metabolic activity in T cells, we performed non-targeted metabolomics on plasma and spleens from scGVHD animals. Clustering of splenic metabolite intensities across treatment groups revealed a subset of metabolites responsive to MALT1 inhibition. This motivated us to explore the metabolic activity of cells from GVHD patients. By developing a method to infer metabolic pathway activity from transcriptional profiles of whole blood, we were able to utilize publicly available RNA-seq data. Using a data set containing 8 healthy controls and longitudinal samples from 25 GVHD patients, this approach segregated GVHD patients into four subsets, with the two largest subsets showing oppositional activity in most major metabolic pathways. Collectively, these data reveal a breadth of MALT1 activity across diverse cell types implicated in the initiation and progression of cGVHD and support development of small-molecule inhibitors of MALT1. These data also define novel heterogeneity among GHVD patients based on immunometabolic activity and motivate development of metabolic biomarkers of MALT1 activity for clinical use. [Display omitted] DisclosuresDispirito: Rheos Medicines: Current Employment. Badur: Rheos Medicines: Current Employment. Biswas: Rheos Medicines: Current Employment. Camacho: Rheos Medicines: Current Employment. Chalishazar: Rheos Medicines: Current Employment. DeChristopher: Rheos Medicines: Current Employment. Sellers: Rheos Medicines: Current Employment. Steadman: Rheos Medicines: Current Employment. Soh: Rheos Medicines: Current Employment. Monroe: Rheos Medicines: Consultancy. Long: Rheos Medicines: Current Employment.

Characterization of Potent Paracaspase MALT1 Inhibitors for Hematological Malignancies

Introduction: MALT1 (mucosa-associated lymphoid tissue lymphoma translocation protein 1) is a key mediator of the NF-κB signaling pathway, the main driver of a subset of B-cell lymphomas and functions by forming a complex with CARMA1 and BCL10 to mediate antigen receptor-induced lymphocyte activation. MALT1 is considered a potential therapeutic target for several subtypes of non-Hodgkin B-cell lymphomas and chronic lymphocytic leukemia (CLL). Previously, we described the discovery of novel and potent MALT1 inhibitors with anti-proliferative effects in non-Hodgkin B-cell lymphoma cells. Here, we highlight the strong anti-tumor activity of our MALT1 inhibitors across multiple tumor models and the combination potential with agents including standard-of-care.Results: Novel small molecule MALT1 inhibitors were identified using Schrodinger's proprietary physics-based free energy perturbation (FEP+) modeling technology. These molecules demonstrate strong MALT1 protein binding affinity, potent inhibition of MALT1 enzymatic activity and anti-proliferative activity in the activated B-cell (ABC) subtype of diffuse large B cell lymphoma (DLBCL) cell lines such as OCI-LY3 and OCI-LY10. In combination with approved agents, these inhibitors demonstrate strong combination potential with Bruton's tyrosine kinase (BTK) inhibitors such as ibrutinib in ABC-DLBCL cell lines. In ABC-DLBCL CDX models, our representative MALT1 inhibitor induces tumor regression as a single agent and complete tumor regression in combination with ibrutinib. Our representative MALT1 inhibitor, when tested in LY2298 PDX models, demonstrates similar results. In addition, our representative MALT1 inhibitor was explored in a CDX model derived from a Mantle cell lymphoma REC-1 cell line, and demonstrates strong anti-tumor activity of ~78% tumor growth inhibition (TGI) as a single agent.Conclusions: Schrodinger's novel, potent MALT1 protease small molecule inhibitors are efficacious in in vitro B-cell lymphoma cell proliferation assays and in in vivo B-cell lymphoma xenograft models. These data suggest that targeting MALT1 may expand therapeutic options for patients with selected B-cell lymphomas, such as ABC-DLBCL, with the possibility of expanding into other B-cell lymphomas such as MCL. Furthermore, these small molecule MALT1 inhibitors demonstrate potential in combination with BTKi to overcome drug-induced resistance in patients with relapsed/refractory B-cell lymphomas. Taken together, the data presented here strongly underscore the therapeutic potential of our MALT1 inhibitor and support further evaluation in clinical trials. DisclosuresWeiss: Schrodinger: Current Employment; ARTham Therapeutics: Membership on an entity's Board of Directors or advisory committees.

Discovery and optimization of cyclohexane-1,4-diamines as allosteric MALT1 inhibitors

Inhibition of mucosa-associated lymphoid tissue lymphoma translocation protein-1 (MALT1) is a promising strategy to modulate NF-κB signaling, with the potential to treat B-cell lymphoma and autoimmune diseases. We describe the discovery and optimization of (1s,4s)-N,N′-diaryl cyclohexane-1,4-diamines, a novel series of allosteric MALT1 inhibitors, resulting in compound 8 with single digit micromolar cell potency. X-ray analysis confirms that this compound binds to an induced allosteric site in MALT1. Compound 8 is highly selective and has an excellent in vivo rat PK profile with low clearance and high oral bioavailability, making it a promising lead for further optimization.

1035TiP A phase I/Ib study of MPT-0118 as monotherapy and in combination with pembrolizumab in subjects with advanced or metastatic solid tumors

MPT-0118 is an inhibitor of mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) protease developed by Monopteros Therapeutics for the treatment of solid tumors. Despite the transforming effects of immune checkpoint therapy (ICT), objective response rates are still low in solid tumors. In the tumor microenvironment (TME), regulatory T-cells (Treg) are unstable and can be reprogrammed to lose their immunosuppressive function and secrete interferon-γ, offering a strategy to sensitize unresponsive tumors to ICT.

Abstract 1267: Combination therapy of JNJ-67856633, a novel, first-in-class MALT1 protease inhibitor, and JNJ-64264681, a novel BTK inhibitor, for the treatment of B-cell lymphomas

Abstract Background: Constitutive activation of the classical nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-κB) pathway is a clear driver of B-cell non-Hodgkin lymphomas (NHL). Bruton's Tyrosine Kinase (BTK) and Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1), which lies downstream of BTK, are key mediators of the classical NF-κB signaling pathway activated by BCR and TCR receptors. JNJ-67856633 is a first-in-class MALT1 protease inhibitor. JNJ-64264681 is a BTK inhibitor with improved selectivity against BTK. Blocking the BCR pathway at multiple points using these two orally bioavailable compounds could enhance clinical activity in B-cell lymphoma patients. Methods: JNJ-67856633 and JNJ-64264681 are currently being evaluated in phase 1 clinical trials designed to establish safety, PK, PD and the Recommended Phase 2 Dose (RP2D) of each agent. Results: JNJ-67856633 is a potent, selective, orally bioavailable, allosteric inhibitor of MALT1 protease activity. The compound inhibits proliferation of activated B-cell diffuse large B-cell lymphoma (ABC-DLBCL) cell lines bearing CD79b or CARD11 mutations as well as models mimicking resistance to covalent BTK inhibitors. JNJ-67856633 exhibits potent tumor growth inhibition in two human DLBCL xenograft models, OCI-Ly3 and OCI-Ly10, and mutation selected patient derived DLBCL xenografts. Furthermore, treatment with JNJ-67856633 leads to dose dependent inhibition of the generation of Tregs (CD4+CD25+FoxP3+) following CD3/28 stimulation in vitro, suggesting a potential immune modulatory role of MALT1 inhibition. JNJ-64264681 is an orally active small molecule that is a potent, selective, and irreversible covalent BTK inhibitor. JNJ-64264681 inhibits the growth of CD79b-mutant DLBCL cell lines in vitro and potently inhibits tumor growth in xenograft- or patient-derived DLBCL models in vivo. Treatment with JNJ-64264681 and JNJ-67856633 administered together demonstrated statistically significant tumor growth inhibition compared with vehicle control in two CD79b mutant mouse lymphoma models, one based on a DLBCL cell line (OCI-Ly10) and one based on a patient-derived DLBCL model (LY2298). In both models, the combination showed increased growth inhibition compared with single agents and tumor regression in the combination arm. Synergistic anti-proliferative activity was observed in three DLBCL cell lines carrying CD79b mutations and one MCL cell line. Conclusions: Taken together, the in vitro and in vivo data for JNJ-67856633 and JNJ-64264681 suggest that combination therapy can increase the anti-tumor effect of the monotherapies and provide a more sustained response, offering strong support for clinical investigation of the combination of these two novel agents. A phase 1b combination study is scheduled to initiate. Citation Format: Ulrike Philippar, Lorena Fontan, Ivo Cornelissen, Haopeng Rui, Sriram Balasubramanian, Marcello Gaudiano, Mariette Bekkers, Luc Van Nuffel, Tianbao Lu, Tianbao Lu, John Wiener, Mark Tichenor, Tony Greway, Kathryn Packman, Bie Verbist, Yusri Elsayed, Ricardo Attar, Jacqueline Bussolari, John Gerecitano. Combination therapy of JNJ-67856633, a novel, first-in-class MALT1 protease inhibitor, and JNJ-64264681, a novel BTK inhibitor, for the treatment of B-cell lymphomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1267.

Identification of Novel Fused Heteroaromatics-Based MALT1 Inhibitors by High-Throughput Screening to Treat B Cell Lymphoma.

Development of mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) inhibitors is of great value and significance in the treatment of neoplastic disorders and inflammatory and autoimmune diseases. However, there is a lack of effective MALT1 inhibitors in clinic. Herein, a novel class of potent 5-oxo-1-thioxo-4,5-dihydro-1H-thiazolo[3,4-a]quinazoline-based MALT1 inhibitors and their covalent derivatives were first identified and designed through high-throughput screening. We demonstrated that compounds 15c, 15e, and 20c effectively inhibited the MALT1 protease and displayed selective cytotoxicity to activated B cell-like diffuse large B cell lymphoma with low single-digit micromolar potency. Furthermore, compound 20c specifically repressed NF-κB signaling and induced cell apoptosis in MALT1-dependent TMD8 cells in a dose-dependent manner. More importantly, 20c showed good pharmacokinetic properties and antitumor efficacy with no significant toxicity in the TMD8 xenograft tumor model. Collectively, this study provides valuable lead compounds of MALT1 inhibitors for further structural optimization and antitumor mechanism study.

MALT-1 inhibition attenuates the inflammatory response of ankylosing spondylitis by targeting NF-κB activation

The present study aimed to investigate the effects of mucosa-associated lymphoid tissue lymphoma translocation protein (MALT)-1 on ankylosing spondylitis and its underlying mechanisms. Proteoglycan induced ankylosing spondylitis (PGIA) mouse model was established and the expression patterns of MALT-1 were determined in joint tissue. Next, the mice were intraarticularly administrated with MALT-1 in the PGIA mouse model. Meanwhile, shRNA was intraarticularly administrated to PGIA mice. The incidence of arthritis and clinical score was evaluated. Besides, the levels of inflammatory cytokines and matrix metalloproteinases (MMPs) were measured. Protein expressions of full-length CYLD (FL-CYLD), C-terminal cleavage fragment (CYLD-CL), and nuclear factor (NF)-κB were determined. The mRNA and protein levels of MALT1 were increased in the PGIA mouse model. The treatment of MALT-1 accelerated arthritis incidence and joint damage, whereas shMALT-1 suppressed arthritis symptoms in the PGIA mouse model. In addition, treatment of shMALT-1 suppressed the levels of inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β), MMP-3, and MMP-9. Furthermore, the treatment of shMALT-1 suppressed the levels of CYLD and NF-κB in the joint tissues in the PGIA mouse model. The inhibition of MALT-1 suppressed the inflammatory response in ankylosing spondylitis in part by the regulation of CYLD and NF-κB.

MALT1 as a promising target to treat lymphoma and other diseases related to MALT1 anomalies.

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) is a key adaptor protein that regulates the NF-κB pathway, in which MALT1 functions as a scaffold protein and protease to trigger downstream signals. The abnormal expression of MALT1 is closely associated with lymphomagenesis and other diseases, including solid tumors and autoimmune diseases. MALT1 is the only protease in the underlying pathogenesis of these diseases, and its proteolytic activity can be pharmacologically regulated. Therefore, MALT1 is a potential and promising target for anti-lymphoma and other MALT1-related disease treatments. Currently, the development of MALT1 inhibitors is still in its early stages. This review presents an overview of MALT1, particularly its X-ray structures and biological functions, and elaborates on the pathogenesis of diseases associated with its dysregulation. We then summarize previously reported MALT1 inhibitors, focusing on their molecular structure, biological activity, structure-activity relationship, and limitations. Finally, we propose future research directions to accelerate the discovery of novel MALT1 inhibitors with clinical applications. Overall, this review provides a comprehensive and systematic overview of MALT1-related research advances and serves as a theoretical basis for drug discovery and research.

NF-κB subunit RELA suppression of mucosa-associated lymphoid tissue lymphoma translocation protein 1 expression in oral carcinoma cells

Loss of mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) expression closely associates with increased aggressive behaviors of oral carcinoma cells. It emphasizes that a mechanism to suppress the expression is an important subject for understanding carcinoma progression pathway. However, nothing is known at present. This study conducted on transcriptional regulation of the gene down-regulation. Reporter assays showed the presence of the silencer region between +402 and +501 region of MALT1 gene in oral carcinoma cells. It encoded a binding site of nuclear factor-κB subunit, RELA. RELA binding to the site was confirmed by the chromatin immunoprecipitation analyses, and deletion and mutations of the site significantly decreased the RELA binding. Short interfering RNAs for RELA up-regulated reporter gene and endogenous MALT1 protein expressions, and deletion and mutations of RELA binding site increased reporter gene expression. These results demonstrated RELA-binding to the site suppresses MALT1 expression that may facilitate oral carcinoma progression.

Anticancer Activity of Lesbicoumestan in Jurkat Cells via Inhibition of Oxidative Stress-Mediated Apoptosis and MALT1 Protease.

This study explores the potential anticancer effects of lesbicoumestan from Lespedeza bicolor against human leukemia cancer cells. Flow cytometry and fluorescence microscopy were used to investigate antiproliferative effects. The degradation of mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) was evaluated using immunoprecipitation, Western blotting, and confocal microscopy. Apoptosis was investigated using three-dimensional (3D) Jurkat cell resistance models. Lesbicoumestan induced potent mitochondrial depolarization on the Jurkat cells via upregulated expression levels of mitochondrial reactive oxygen species. Furthermore, the underlying apoptotic mechanisms of lesbicoumestan through the MALT1/NF-κB pathway were comprehensively elucidated. The analysis showed that lesbicoumestan significantly induced MALT1 degradation, which led to the inhibition of the NF-κB pathway. In addition, molecular docking results illustrate how lesbicoumestan could effectively bind with MALT1 protease at the latter’s active pocket. Similar to traditional 2D cultures, apoptosis was markedly induced upon lesbicoumestan treatment in 3D Jurkat cell resistance models. Our data support the hypothesis that lesbicoumestan is a novel inhibitor of MALT1, as it exhibited potent antiapoptotic effects in Jurkat cells.

Correction: HECT E3 ubiquitin ligases – emerging insights into their biological roles and disease relevance

There were errors in J. Cell Sci. (2020) 133, jcs228072 (doi:10.1242/jcs.228072).The authors wish to correct minor omissions regarding HECTD3 in the main text, and the citations for interactions between Malt1 and STAT3 listed in Table S4.New text to explain the role of HECTD3 in the innate immune response was added to the ‘Immune response’ section on page 5 as below:In addition, HECTD3 was recently identified to interact and ubiquitylate mucosa-associated lymphoid tissue lymphoma translocation protein 1 (Malt1) and signal transducer and activator of transcription 3 (STAT3) in pathogenic Th17 cells (Cho et al., 2019). HECTD3 was also observed to ubiquitylate tumor necrosis factor receptor-associated factor 3 (TRAF3) and promote type-I interferon response in macrophages during infection (Li et al., 2018).New rows to Table S4 were added as below:Mucosa-associated lympoid tissue lymphoma translocation protein 1 (MALT1) 2H, IP, MS, PD, WB, UbA DOC(216-393aa) (Cho et al. 2019; Li et al. 2013b).Signal transducer and activator of transcription 3 (STAT3) IP, MS, WB, UbA DOC(110-397) (Cho et al. 2019).The authors apologise to readers for this omission, which does not impact the conclusions of the Review article. Both the online full text and PDF versions of the article and supplementary information have been corrected.

Oncogenic MALT1 Promotes Cell Survival and Mediates Ibrutinib Resistance and Ibrutinib-Venetoclax Resistance in Mantle Cell Lymphoma

Both as monotherapies and in combination, the Bruton's tyrosine kinase inhibitor ibrutinib and the BH3 mimetic BCL2 inhibitor venetoclax have proven to be efficacious and are now widely used treatment options for mantle cell lymphoma (MCL) patients. However, mono- and dual- resistance frequently develops, necessitating investigation into the mechanisms mediating resistance to these therapies. To investigate the mechanism of ibrutinib resistance, we generated two ibrutinib-resistant cells due to marked BTK knockdown via CRISPR/CAS9 from JeKo-1, which is ibrutinib-sensitive and venetoclax-resistant. To understand the mechanism of venetoclax resistance, we generated three venetoclax-resistant cell lines with acquired resistance via chronic exposure to increasing doses of venetoclax from ibrutinib/venetoclax double sensitive Mino and Rec-1 cells, and ibrutinib-resistant but venetoclax-sensitive Granta519 cells. All these paired cell lines with various resistance to ibrutinib and venetoclax were subject to whole transcriptome sequencing of these paired MCL cell lines. We discovered that mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) is significantly overexpressed in ibrutinib-resistant and ibrutinib-venetoclax dual-resistant MCL cells, especially in cells with BTK knockdown. This was further validated in primary MCL patient cells (n=24). Interestingly, MALT1 overexpression inversely correlates with CARD11 expression and enhances non-canonical NF-κB signaling, suggesting a switch from a highly-dependent BTK-CARD11 mechanism to an independent mechanism in both ibrutinib-resistant and ibrutinib-venetoclax dual-resistant MCL cells. Chromosomal translocations of MALT1 are the hallmarks of MALT lymphoma, which result in oncogenic fusion of MALT1 products. MALT1 is constitutively active in driving aggressive ABC-type DLBCL. This indicates MALT1 can be oncogenic when its activity is dysregulated. Therefore, we hypothesized that constitutive MALT1 activity may be responsible for the resistance to ibrutinib and venetoclax in MCL cells. To demonstrate this relationship, MALT1 ablation using genetic manipulation resulted in significant growth defects both in vitro and in vivo. Pharmaceutical approaches using MALT1 inhibitor MI-2 resulted in similar effects on cell survival and using cell viability assays. Whole transcriptome sequencing analysis revealed that MYC, NF-kB, ROS, cell cycle and mTOR signaling are the most significantly downregulated pathways upon MI-2 treatment. Intriguingly, MYC, NF-kB, PI3K-AKT-mTOR and mTOR signaling pathways were reported to be upregulated in ibrutinib-resistant MCL cells compared to sensitive MCL cells. To address this further, proteomics analysis by reverse phase protein array (RPPA) using more than 400 antibodies confirmed that MI-2 significantly downregulated AKT-mTOR signaling. NF-kB modulation, ROS production, AKT-mTOR, and metabolism changes were further confirmed through multiple biochemical approaches. In addition, MI-2 treatment resulted in a dramatic reduction of MALT1 expression, suggesting that MI-2 treatment affected both its scaffold and paracaspase activities. Furthermore, MI-2 treatment resulted in significant inhibition of in vivo tumor growth of ibrutinib-venetoclax dual-resistant MCL subcutaneous xenografts and tumor homing to the spleen and bone marrow in an ibrutinib-venetoclax dual-resistant MCL patient-derived xenograft (PDX) mouse model. In conclusion, we discovered that MALT1, an essential regulator of NF-κB signaling, is hyperactive in ibrutinib-resistant cells and ibrutinib-venetoclax dual-resistant MCL cells, which puts MALT1 forward as a potentially new therapeutic target in ibrutinib and venetoclax-resistant MCL tumors. Genetic depletion or pharmaceutical inhibition of MALT1 resulted in remarkable defects in cell survival and cell proliferation. The MALT1 inhibitor MI-2 proved its in vivo potency by its pro-apoptotic effect and its significant tumor growth inhibition. In conclusion, targeting a hyperactive MALT1 is a promising therapeutic strategy that could lead to clinical implementation of a new treatment strategy meant to overcome ibrutinib and ibrutinib-venetoclax dual resistance in MCL patients by reversing the NF-kB and ROS/mTOR- mediated resistance in these tumors. Disclosures Wang: Targeted Oncology: Honoraria; Loxo Oncology: Consultancy, Research Funding; Pulse Biosciences: Consultancy; Kite Pharma: Consultancy, Other: Travel, accommodation, expenses, Research Funding; Juno: Consultancy, Research Funding; BioInvent: Research Funding; VelosBio: Research Funding; Acerta Pharma: Research Funding; InnoCare: Consultancy; Oncternal: Consultancy, Research Funding; Nobel Insights: Consultancy; Guidepoint Global: Consultancy; Dava Oncology: Honoraria; Verastem: Research Funding; Molecular Templates: Research Funding; OncLive: Honoraria; Beijing Medical Award Foundation: Honoraria; Lu Daopei Medical Group: Honoraria; MoreHealth: Consultancy; Celgene: Consultancy, Other: Travel, accommodation, expenses, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; OMI: Honoraria, Other: Travel, accommodation, expenses.