A multiprotein supercomplex controlling oncogenic signalling in lymphoma

BENTA disease or CARD11 gain-of-function? A novel variant with atypical features and a literature review

INTRODUCTION

The CARD11 (Caspase Recruitment Domain Family Member 11) gene encodes a scaffold protein critical for NF-κB signaling, regulating B-cell differentiation and T-cell effector functions. Gain-of-function (GOF) mutations in CARD11 cause BENTA disease (B cell Expansion with NF-κB and T cell Anergy), an autosomal dominant disorder typically presenting with early-onset polyclonal B-cell lymphocytosis, splenomegaly, lymphadenopathy, and recurrent infections.

METHODS

We describe three related patients harboring a novel CARD11-GOF mutation (D357E), presenting with a BENTA phenotype with atypical features, including high IgM levels and a normal B-cell count, with life-threatening HLH in one case. Additionally, we conducted a systematic literature review using PubMed and EMBASE to identify previously reported cases of CARD11 GOF mutations.

RESULTS

In vitro functional analysis demonstrated that the D357E variant activates the NF-κB signaling pathway in primary lymphocytes and in HEK293T cells transfected with mutant CARD11. Our literature review identified 13 studies describing 29 patients. Notably, HLH emerged as a common complication of CARD11 GOF mutations (18.8 %), while B-lymphocytosis -though frequent- was not universally present.

CONCLUSION

We identified a novel pathogenic CARD11 variant and described its atypical phenotype, further expanding the clinical spectrum of CARD11 GOF disorders. These findings underscore the need for increased awareness of HLH risk in patients with CARD11 GOF mutations.

Efficacy and safety of orelabrutinib combined with rituximab and high dose methotrexate in primary or secondary central nervous system diffuse large B-cell lymphoma: a retrospective analysis

Central nervous system lymphoma (CNSL) are mainly diffuse large B-cell lymphomas (DLBCLs). Orelabrutinib is a second-generation Bruton's tyrosine kinase (BTK) inhibitor and has shown single-agent activity in CNSL. This study aims to evaluate the efficacy and safety of orelabrutinib combined with rituximab and high dose methotrexate (ORM) regimen in the treatment of patients with CNSL. We retrospectively analyzed data from CNSL patients treated with ORM regimen at Jiangsu Province Hospital, the First Affiliated Hospital of Nanjing Medical University from April 2021 to October 2023. Patients receiving rituximab plus high-dose methotrexate (RM regimen) from June 2017 to January 2024 were identified as the control group. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Adverse events (AEs) were assessed according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. A total of 32 patients were identified: 14 patients in the ORM group and 18 in the RM group. CR rates were 84.6% in the ORM group and 44.4% in the RM group (P = 0.032). Median PFS was 18.6 months in the RM group and 26.3 months in the ORM group (P = 0.133). Median OS was 34.1 months in the RM group and has not yet been reached in the ORM group (P = 0.041). Patients in the ORM group showed a higher 2-year OS rate than those in the RM group (82.1% vs. 57.5%). No grade 5 AE was reported in both groups. The incidence of grade 3-4 AE was comparable between the two treatment groups. ORM regimen was effective and well-tolerated in patients with CNSL. This combination therapy provides a new potential therapeutic strategy for patients with CNSL.

Toll-like receptor 9 (TLR9) expression correlates with cell of origin and predicts clinical outcome in diffuse large B-cell lymphoma

BACKGROUND

Biological insights beyond the cell-of-origin (COO) classification can support clinical management in diffuse large B-cell lymphoma (DLBCL). We investigated if Toll-like receptor 9 (TLR9) expression could serve as a prognostic marker in DLBCL.

METHOD

TLR9 gene expression was analysed in four publicly available cohorts (n = 2474), and protein expression was investigated in germinal centre B-cell (GCB) and activated B-cell (ABC) DLBCL cell lines. Next, TLR9 protein expression was analysed in 120 diagnostic samples from R-CHOP-treated patients with relapsed/refractory disease (poor outcome, n = 50) or in complete remission (good outcome, n = 70). Associations were evaluated using logistic regression, estimating odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

TLR9 gene expression was higher in ABC DLBCL compared to GCB DLBCL in external cohorts, and similar results were obtained for protein expression in cell lines. In patient samples, high TLR9 protein expression correlated with non-GCB type (p = 0.003) and poor outcome (p = 0.0016). High TLR9 expression remained associated with poor outcome in multivariable analysis after adjusting for COO and other clinical features (OR = 3.36, 95% CI 1.41-8.04). In exploratory analyses, a decrease of cell growth in ABC cell lines following inhibition of TLR9 activity with ODN4084-F was suggested.

CONCLUSION

We conclude that TLR9 correlates with ABC/non-GCB phenotype and is a potential predictor of poor prognosis in DLBCL.

A highly selective and orally bioavailable casein kinase 1 alpha degrader through p53 signaling pathway targets B-cell lymphoma cells

The modest reduction in casein kinase 1 alpha (CK1α) by lenalidomide contributes to its clinical effectiveness in treating del(5q) myelodysplastic syndrome. However, the mechanism by which CK1α impacts lymphoma survival remains inadequately defined. We developed INNO-220, a CRBN-dependent CK1α degrader, by leveraging cytokine expression profiling in T cells. Unlike lenalidomide, INNO-220 is a highly selective and potent degrader of CK1α without affecting IKZF1/3. Screening across lymphoma cell lines revealed that cells harboring wild-type p53 and exhibiting constitutive NF-κB signaling were particularly sensitive to CK1α degradation yet resistant to Bruton tyrosine kinase inhibitors. Moreover, INNO-220 suppresses NF-κB signaling and activates p53 pathway, leading to complete inhibition of lymphoma tumor growth in vivo. Mechanistically, INNO-220 disrupts the assembly and function of the CARD11/BCL10/MALT1 complex, thereby inhibiting NF-κB signaling in stimulated T cells and lymphoma cells that harbor an activating mutation in CARD11. Moreover, we observed that activation of wild-type p53 upon INNO-220 treatment was sufficient to induce potent cancer cell death even in the absence of constitutive NF-κB activity. In summary, our findings introduce a selective CK1α degrader as a novel therapeutic approach for lymphoma, providing both mechanistic insights and a potential patient selection strategy in treating lymphoma and possibly other cancers.

Integrative genomic analysis of DLBCL identifies immune environments associated with bispecific antibody response

ABSTRACT

Most patients with diffuse large B-cell lymphoma (DLBCL) treated with immunotherapies such as bispecific antibodies (BsAbs) or chimeric antigen receptor (CAR) T cells fail to achieve durable treatment responses, underscoring the need for a deeper understanding of mechanisms that regulate the immune environment and response to treatment. Here, an integrative multiomics approach was applied to multiple large independent data sets to characterize DLBCL immune environments and to define their association with tumor cell-intrinsic genomic alterations and outcomes to CD19-directed CAR T-cell and CD20 × CD3 BsAb therapies. This approach effectively segregated DLBCLs into 4 immune quadrants (IQs) defined by cell-of-origin and immune-related gene set expression scores. These quadrants consisted of activated B cell-like (ABC) hot, ABC cold, germinal center B cell-like (GCB) hot, and GCB cold DLBCLs. Recurrent genomic alterations were enriched in each IQ, suggesting that lymphoma cell-intrinsic alterations contribute significantly to orchestrating unique DLBCL immune environments. For instance, SOCS1 loss-of-function mutations were significantly enriched among GCB hot DLBCLs, identifying a putative subset of inflamed DLBCLs that may be inherently susceptible to immunotherapy. In patients with relapsed/refractory DLBCL, DLBCL-IQ assignment correlated significantly with clinical benefit with a CD20 × CD3 BsAb (N = 74), but not with CD19-directed CAR T cells (Stanford, N = 51; Memorial Sloan Kettering Cancer Center, N = 69). Thus, DLBCL-IQ provides a new framework to conceptualize the DLBCL immune landscape and suggests the endogenous immune environment has a more significant impact on outcomes to BsAb than CAR T-cell treatment.

CD20 and CD19 promote proliferation driven by the IgM-TLR9-L265P MyD88 complex

The cancer driver mutation L265P MyD88 is found in approximately 30% of cases in the activated B cell-like subgroup of diffuse large B cell-like lymphoma (ABC DLBCL). L265P MyD88 forms a complex with TLR9 and IgM, referred to as the My-T-BCR complex, to drive proliferation. We here show that the B cell surface molecules CD19 and CD20 enhance proliferation mediated by the My-T-BCR complex. Using the interleukin 3 (IL-3)-dependent Ba/F3 line transduced to express the IgM complex (IgM, CD79a, and CD79b) and TLR9, we observed proliferation in the presence of anti-IgM antibody and the TLR9 ligand CpG-B. TLR9 was constitutively associated with IgM and L252P MyD88. CD19 promoted proliferation with anti-IgM and CpG-B specifically in L252P MyD88-expressing Ba/F3 cells, while CD20 enhanced the proliferation in both wild-type- and L252P MyD88-expressing Ba/F3 cells. Additionally, CD20 uniquely enabled IgM-mediated proliferation in L252P MyD88-expressing Ba/F3 cells. Although CpG-B was not required for this proliferation, TLR9 expression remained indispensable. In the ABC DLBCL line TMD8, anti-IgM antibody-mediated growth was impaired by the lack of CD20 and CD19 or of TLR9. Mechanistically, CD19 promoted IgM-dependent AKT phosphorylation, whereas CD20 increased expression of cell surface IgM, thereby enhancing the formation of the IgM-TLR9 complex. These findings suggest that CD19 and CD20 differentially contribute to the proliferation driven by the My-T-BCR complex.

Germline mutations predispose a concurrent thymoma and diffuse large B-cell lymphoma

Although thymoma is a rare malignancy, it is usually accompanied by secondary cancers. Non-Hodgkin's B-cell lymphoma is one of the most common secondary neoplasms observed in patients with thymoma, presenting before, concurrently with, or after the diagnosis. However, the underlying molecular mechanism of concomitant thymoma and lymphoma remains unclear. This study aimed to report a case with concurrent extrathymic, diffuse large B-cell lymphoma (DLBCL), and thymoma. Published studies and the SEER database were queried to summarize the features of patients with these concomitant cancers. Whole-exome sequencing (WES) was performed on tumor specimens and buccal swab mucosa. Six germline mutations and several specific somatic alterations were found on each neoplastic tissue, which may elucidate the potential pathogenesis of concurrent cancers. This study was novel in reporting concurrent extrathymic DLBCL and thymoma by applying WES on matched neoplasm-normal samples to explore the pathogenesis of these distinct neoplasms.

Selective Enhancer Dependencies in MYC-Intact and MYC-Rearranged Germinal Center B-cell Diffuse Large B-cell Lymphoma

SIGNIFICANCE

Aberrant MYC activity defines the most aggressive GCB-DLBCLs. We characterized a mechanism of MYC transcriptional activation via a native enhancer that is active in MYC-intact GCB-DLBCL, establishing fitness-sustaining cis- and trans-regulatory circuitry in GCB-DLBCL models that lack MYC enhancer-hijacking rearrangement. See related commentary by Mulet-Lazaro and Delwel, p. 149.

BTK inhibitors resistance in B cell malignancies: Mechanisms and potential therapeutic strategies

Bruton tyrosine kinase inhibitors (BTKi) have shown prominent clinical efficacy in patients with B cell malignancies, such as chronic lymphocytic leukemia, mantle cell lymphoma, diffuse large B cell lymphoma, and Waldenström's macroglobulinemia. Nevertheless, numerous factors contribute to BTKi resistance, encompassing genetic mutations, chromosomal aberrations, dysregulation of protein expression, tumor microenvironment, and metabolic reprogramming. Accordingly, potential therapeutic strategies have been explored to surmount BTKi resistance, including noncovalent BTKi, BTK proteolysis-targeting chimeras, and combination therapies. Herein, we summarize the mechanisms responsible for BTKi resistance as well as the current preclinical and clinical strategies to address BTKi resistance in B cell malignancies treatment.

Audit of B-cell cancer genes

ABSTRACT

Comprehensive genetic analysis of tumors with exome or whole-genome sequencing has enabled the identification of the genes that are recurrently mutated in cancer. This has stimulated a series of exciting advances over the past 15 years, guiding us to new molecular biomarkers and therapeutic targets among the common mature B-cell neoplasms. In particular, diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and Burkitt lymphoma (BL) have each been the subject of considerable attention in this field. Currently, >850 genes have been reported as targets of protein-coding mutations in at least 1 of these entities. To reduce this to a manageable size, we describe a systematic approach to prioritize and categorize these genes, based on the quality and type of supporting data. For each entity, we provide a list of candidate driver genes categorized into Tier 1 (high-confidence genes), Tier 2 (candidate driver genes), or Tier 3 (lowest-confidence genes). Collectively, this reduces the number of high-confidence genes for these 3 lymphomas to a mere 144. This further affirms the substantial overlap between the genes relevant in DLBCL and each of FL and BL. These highly curated and annotated gene lists will continue to be maintained as a resource to the community. These results emphasize the extent of the knowledge gap regarding the role of each of these genes in lymphomagenesis. We offer our perspective on how to accelerate the experimental confirmation of drivers using a variety of model systems, using these lists as a guide for prioritizing genes.

The single-cell immune landscape of HIV-associated aggressive B-cell lymphoma

Background

Human immunodeficiency virus (HIV)-associated lymphomas (HAL), mainly aggressive B-cell lymphomas, pose a significant challenge in cancer research due to their multifaceted pathogenesis and aggressive clinical course. Despite the clinical importance, the genomic and immune characteristics of these lymphomas remain poorly elucidated.

Methods

We employed single-cell RNA sequencing (scRNA-seq) on lymph node samples from aggressive B-cell lymphomas, mainly including 6 cases of diffuse large B-cell lymphoma (DLBCL) and 5 cases of Burkitt lymphoma (BL) from people living with HIV (PLWH), along with 3 DLBCL cases from individuals without HIV for comparison.

Results

Malignant B cells in HAL consistently exhibited high proliferative and oxidative phosphorylation (OXPHOS)-type metabolic signatures. Moreover, these cells demonstrated loss expression of major histocompatibility complex class I (MHC-I), strategically reducing tumor immunogenicity. HAL harbors special populations of naive and atypical memory B cells that exhibited high metabolic and immune-activated transcriptional profiles. Additionally, HAL exhibited senescence-like dysfunction in T cells, characterized by the reductions in regulatory activity of Treg and cytotoxic activity of CD8+ T cells, as well as decreases expression of IL7R genes and increases expression of FOS and FOSB genes. Our immunofluorescence results showed that the cytotoxic CD8+ T cells in HAL may have a dysfunction of lytic granule polarization. Furthermore, macrophages from HAL exhibited stronger immunosuppressive transcriptional characteristics, and a robust immunosuppressive SPP1-CD44 interaction was predicted between C1QA+ macrophages and T cells.

Conclusions

Our findings clearly indicate that HAL differs significantly from non-HAL, ranging from malignant B cells to the immune microenvironment. This study provides a comprehensive single-cell atlas of HIV-associated aggressive B-cell lymphomas, offering new insights into aggressiveness and immune evasion observed in HAL.

In the era of targeted therapy and immunotherapy: advances in the treatment of large B-cell lymphoma of immune-privileged sites

Primary large B-cell lymphomas of immune-privileged sites (IP-LBCLs) include primary central nervous system large B-cell lymphoma (PCNSL), primary vitreoretinal large B-cell lymphoma (PVRL), and primary testicular large B-cell lymphoma (PTL). These tumors not only have a unique anatomical distribution but also exhibit specific biological and clinical characteristics. Given the high biological overlap between intravascular large B-cell lymphoma (IVLBCL) and IP-LBCLs, and the fact that IVLBCL is confined to the intravascular microenvironment, IVLBCL is currently included in the category of IP-LBCLs. IP-LBCLs are associated with suboptimal prognosis. However, advancements in biomarker detection technologies have facilitated novel therapeutic approaches for this disease entity. This review aims to summarize and analyze the latest research progress in IP-LBCLs, with a focus on new treatment strategies in the era of targeted therapy and immunotherapy. It is intended to further understand the biological characteristics, treatment, and latest advancements of this disease.

Genome-wide CRISPR/Cas9 screen reveals factors that influence the susceptibility of tumor cells to NK cell-mediated killing

BACKGROUND

Natural killer (NK) cells exhibit potent cytotoxic activity against various cancer cell types. Over the past five decades, numerous methodologies have been employed to elucidate the intricate molecular mechanisms underlying NK cell-mediated tumor control. While significant progress has been made in elucidating the interactions between NK cells and tumor cells, the regulatory factors governing NK cell-mediated tumor cell destruction are not yet fully understood. This includes the diverse array of tumor ligands recognized by NK cells and the mechanisms that NK cells employ to eliminate tumor cells.

METHODS

In this study, we employed a genome-wide CRISPR/Cas9 screening approach in conjunction with functional cytotoxicity assays to delineate the pathways modulating the susceptibility of colon adenocarcinoma HCT-116 cells to NK cell-mediated cytotoxicity.

RESULTS

Analysis of guide RNA distribution in HCT-116 cells that survived co-incubation with NK cells identified ICAM-1 as a pivotal player in the NKp44-mediated immune synapse, with NKp44 serving as an activating receptor crucial for the elimination of HCT-116 tumor cells by NK cells. Furthermore, disruption of genes involved in the apoptosis or interferon (IFN)-γ signaling pathways conferred resistance to NK cell attack. We further dissected that NK cell-derived IFN-γ promotes mitochondrial apoptosis in vitro and exerts control over B16-F10 lung metastases in vivo.

CONCLUSION

Monitoring ICAM-1 levels on the surface of tumor cells or modulating its expression should be considered in the context of NK cell-based therapy. Furthermore, promoting FasL expression on the NK cell surface is reaffirmed as an important strategy to enhance NK cell-mediated tumor killing, offering an additional avenue for therapeutic optimization. Additionally, considering the diffusion properties of IFN-γ, our findings highlight the potential of leveraging NK cell-derived IFN-γ to enhance direct tumor cell killing and facilitate bystander effects via cytokine diffusion, warranting further investigation.

Interaction between stromal cells and tumor cells promotes GCB-DLBCL cell survival via the CD40/RANK-KDM6B-NF-κB axis

The stromal cells as the main component of the tumor microenvironment in germinal center B cell-like diffuse large B cell lymphoma (GCB-DLBCL) probably is accountable for therapy resistance and relapse. To investigate the interaction between tumor cells and stromal cells, we established GCB-DLBCL patient-derived xenograft models to isolate primary tumor cells and coculture them with stromal cells. Additionally, we presented GCB-DLBCL cases with histopathologic confirmation and analyzed the online databases to explore the underlying mechanisms. We demonstrated that CD40 ligand (CD40L) expressed on stromal cells activated the CD40 pathway in GCB-DLBCL tumor cells, protecting tumor cells from apoptosis and up-regulating RANK ligand (RANKL). The RANKL expressed on tumor cells enhanced the expression of CD40L and BAFF in stromal cells, which in turn promoted tumor cells survival through activating NF-κB signaling. Significantly, the activation of CD40 pathway up-regulated KDM6B, a lysine-specific demethylase, and KDM6B further enhanced the transcription activity of NF-κB signaling, which has not been reported in B cells. Here, we provided compelling evidence that the interaction between stromal cells and tumor cells functions as a bona fide anti-apoptotic factor in GCB-DLBCL. This interaction mainly involves the CD40/RANK-KDM6B-NF-κB axis, which represents a promising therapeutic target for GCB-DLBCL.

MALT1 Inhibitors and Degraders: Strategies for NF-κB-Driven Malignancies

Mucosa-associated lymphoid tissue protein 1 (MALT1), a cysteine protease and the sole paracaspase in humans, plays a pivotal role in the survival and proliferation of NF-κB-dependent malignant cancers, particularly MALT lymphoma and diffuse large B-cell lymphoma (DLBCL). Dysregulated MALT1 activity is implicated in various malignancies, highlighting its importance as a therapeutic target. This Perspective provides an overview of MALT1's structural and functional characteristics, summarizes recent advancements in small-molecule inhibitors and degraders targeting this protein, and discusses compound structures, structure-activity relationship (SAR) analyses, and biological activities. We aim to inform future research efforts to enhance the activity, selectivity, and pharmacological properties of MALT1-targeting compounds, establishing a foundational framework for drug development in this critical area of cancer therapy.

Fatty Acid Metabolism Provides an Essential Survival Signal in OxPhos and BCR DLBCL Cells

Backgroung/objectives: Diffuse large B-cell lymphoma (DLBCL) is the most frequent subtype of malignant lymphoma and is a heterogeneous disease with various gene and chromosomal abnormalities. The development of novel therapeutic treatments has improved DLBCL prognosis, but patients with early relapse or refractory disease have a poor outcome (with a mortality of around 40%). Metabolic reprogramming is a hallmark of cancer cells. Fatty acid (FA) metabolism is frequently altered in cancer cells and recently emerged as a critical survival path for cancer cell survival. Methods: We first performed the metabolic characterization of an extended panel of DLBCL cell lines, including lipid droplet content. Then, we investigated the effect of drugs targeting FA metabolism on DLBCL cell survival. Further, we studied how the combination of drugs targeting FA and either mitochondrial metabolism or mTOR pathway impacts on DLBCL cell death. Results: Here, we reveal, using a large panel of DLBCL cell lines characterized by their metabolic status, that targeting of FA metabolism induces massive DLBCL cell death regardless of their OxPhos or BCR/glycolytic subtype. Further, FA drives resistance of DLBCL cell death induced by mitochondrial stress upon treatment with either metformin or L-asparaginase, two FDA-approved antimetabolic drugs. Interestingly, combining inhibition of FA metabolism with that of the mTOR oncogenic pathway strongly potentiates DLBCL cell death. Conclusion: Altogether, our data highlight the central role played by FA metabolism in DLBCL cell survival, independently of their metabolic subtype, and provide the framework for the use of drugs targeting this metabolic vulnerability to overcome resistance in DLBCL patients.

High Prevalence of MYD88 and CD79B Mutations in Primary Sinonasal Diffuse Large B-Cell Lymphoma : Identification of an MCD-like Subtype

Primary sinonasal diffuse large B-cell lymphoma (PSDLBCL) is a rare aggressive lymphoma. Recently, genetic classification using Next Generation Sequencing (NGS) demonstrated that PSDLBCL largely consists of the MCD genotype, which has a poor prognosis mainly driven by MYD88 L265P and CD79B gene abnormalities. This study investigated the prevalence and clinicopathological significance of MYD88 L265P and CD79B Y196 mutations using droplet digital PCR in 55 patients with PSDLBCL, as well as the translocation of BCL2 / BCL6 / c-Myc with FISH. We found mutations in MYD88 L265P (29/55, 52.7%) and CD79B Y196 (20/55, 36.4%). The MCD-like subtype, defined by the mutation of MYD88 and/or CD79B , was found in 32 out of 55 cases (58.2%). This subtype largely consists of non-GCB type (31/32, 96.9%; P <0.01) and double-expressor cases (20/32, 62.5%; P =0.01) compared with the MYD88 / CD79B co-wild type, with BCL6 translocation in a small subset (2/32, 6.3%) and no translocations of BCL2 (0/32) or c-Myc (0/32). The MCD-like subtype tended to relapse in specific sites such as the central nervous system, testis, and/or skin compared with the co-wild type ( P =0.03), showing poorer outcomes in overall survival ( P =0.02) and progression-free survival ( P =0.01). In conclusion, our study highlights a high prevalence of MYD88 and CD79B mutations in PSDLBCL, identifying an aggressive MCD-like subtype with a distinct relapse pattern. This molecular subclassification can be helpful for both prognostic prediction and therapeutic strategy in patients with PSDLBCL.

A rare case of splenic marginal zone lymphoma with MYD88 mutation transformed into diffuse large B-cell lymphoma: case report and literature review

In indolent lymphomas, histological transformation (HT) often results in a poor prognosis and presents a significant challenge in the management of these lymphomas. Previous studies have indicated that MYD88 mutations are associated with transformation in certain haematologic malignancies. We report a rare case of splenic marginal zone lymphoma (SMZL) harbouring an MYD88 mutation, which was transformed into diffuse large B-cell lymphoma (DLBCL) and accompanied by newly emerging genetic abnormalities. The role of the MYD88 gene in SMZL is currently unclear. Through this case, we reviewed relevant studies, which indicated that MYD88 mutations, along with other genetic anomalies, may play a significant role in this process. In the future, it is essential to collect more of these rare cases for further research.

Comparison of differences in transcriptional and genetic profiles between intra-central nervous system and extra-central nervous system large B-cell lymphoma

Primary central nervous system diffused large B-cell lymphoma (PCNS-DLBCL) is a rare type of non-Hodgkin lymphoma restricted to the central nervous system (CNS). To explore its specific pathogenesis and therapeutic targets, we performed multi-omics sequencing on tumor samples from patients diagnosed with PCNS-DLBCL, secondary CNS-DLBCL or extracranial (ec) DLBCL.By single-cell RNA sequencing, highly proliferated and dark zone (DZ)-related B cell subclusters, MKI67_B1, PTTG1_B2 and BTG1_B3, were predominant significantly in PCNS-DLBCL. Compared to SCNS-DLBCL and ecDLBCL, an immune-suppressive tumor microenvironment was observed in PCNS-DLBCL by analysis of immune-stimulating/inhibitory ligand‒receptor (L-R) pairs. By performing whole-exome sequencing in 93 patients, mutations enriched in BCR-NFkB and TLR pathways and the cooperation of these two pathways were found to be predominant in PCNS-DLBCL comparing to nonGCB-ecDLBCL. In summary, our study provides comprehensive insights into the transcriptomic and genetic characteristics of PCNS-DLBCL in contrast to ecDLBCL and will help dissect the oncogenic mechanism of this disease.

T Cells Spatially Regulate B Cell Receptor Signaling in Lymphomas through H3K9me3 Modifications

Activated B cell-like diffuse large B-cell lymphoma (ABC-DLBCL) is a subtype associated with poor survival outcomes. Despite identifying therapeutic targets through molecular characterization, targeted therapies have limited success. New strategies using immune-competent tissue models are needed to understand how DLBCL cells evade treatment. Here, synthetic hydrogel-based lymphoma organoids are used to demonstrate how signals in the lymphoid tumor microenvironment (Ly-TME) can alter B cell receptor (BCR) signaling and specific histone modifications, tri-methylation of histone 3 at lysine 9 (H3K9me3), dampening the effects of BCR pathway inhibition. Using imaging modalities, T cells increase DNA methyltransferase 3A expression and cytoskeleton formation in proximal ABC-DLBCL cells, regulated by H3K9me3. Expansion microscopy on lymphoma organoids reveals T cells increase the size and quantity of segregated H3K9me3 clusters in ABC-DLBCL cells. Findings suggest the re-organization of higher-order chromatin structures that may contribute to evasion or resistance to therapy via the emergence of novel transcriptional states. Treating ABC-DLBCL cells with a G9α histone methyltransferase inhibitor reverses T cell-mediated modulation of H3K9me3 and overcomes T cell-mediated attenuation of treatment response to BCR pathway inhibition. This study emphasizes the Ly-TME's role in altering DLBCL fate and suggests targeting aberrant signaling and microenvironmental cross-talk that can benefit high-risk patients.

Targeting spleen tyrosine kinase (SYK): structure, mechanisms and drug discovery

Spleen tyrosine kinase (SYK) is a crucial non-receptor tyrosine kinase involved in signaling pathways that regulate various cellular processes. It is primarily expressed in hematopoietic cells and myeloid cells, which are crucial for B-cell development, maturation and antibody production, and it is a key therapeutic target for autoimmune and allergic diseases. Overexpression of SYK is also associated with cancer and cardiovascular, cerebrovascular and neurodegenerative diseases, contributing to their initiation and progression. SYK is a promising target for drug development, and several inhibitors have already been reported. This review covers the structure and regulatory pathways of SYK, as well as its links to various diseases. It also highlights key small-molecule SYK inhibitors, their design strategies and their potential therapeutic benefits, aiming to enhance our understanding and aid in the discovery of more-effective SYK inhibitors.

Genotype from Phenotype: Using CRISPR Screens to Dissect Lymphoma Biology

Genome-wide screens are a powerful technique to dissect the complex network of genes regulating diverse cellular phenotypes. The recent adaptation of the CRISPR-Cas9 system for genome engineering has revolutionized functional genomic screening. Here, we present protocols used to introduce Cas9 into human lymphoma cell lines, produce high-titer lentivirus of a genome-wide sgRNA library, transduce and culture cells during the screen, select cells with a specified phenotype, isolate genomic DNA, and prepare a custom library for next-generation sequencing. These protocols were tailored for loss-of-function CRISPR screens in human B-cell lymphoma cell lines but are highly amenable for other experimental purposes.

The prognostic significance of MYC/BCL2 double expression in DLBCL in the genetic classification era

Double expression (DE) is a World Health Organization-recognized adverse prognostic factor in diffuse large B-cell lymphoma (DLBCL). However, the prognostic value of DE in the genetic subtyping era and potential mechanisms remain to be explored. We enrolled 246 DLBCL patients diagnosed between December 2021 and September 2023 in a Jiangsu Province Hospital cohort and included 930 DLBCL patients from three published studies in an external cohort. Double-expression DLBCL (DEL) in the external cohort was mainly distributed in the OTHER subtype (42.0%), EZB subtype (28.3%), and MCD subtype (15.0%), whereas the MCD subtype exhibited the highest ratio of DEL. DEL was significantly related to unfavorable overall survival (OS) and progression-free survival (PFS) in DLBCL, but only in EZB and OTHER subtypes that DEL retained remarkably adverse impacts on survivals compared to non-DEL. We explored the prognostic value of clinical and genetic parameters in DEL patients and found only ST2 showed better OS than A53 in DEL patients, whereas the other subtypes showed no significant difference. DEL showed similarities with the MCD subtype in mutation profiles. Furthermore, RNA-sequencing analyses exhibited upregulation in tumor proliferation-related pathways in DEL patients, but downregulation in extracellular matrix organization, T-cell activation and proliferation, type II interferon production, and pathways associated with cell death might contribute to the poor outcomes of DEL patients.

Use of Proximity Ligation Assay to Study Lymphoid Malignancies

The advent of high-throughput and unbiased proteogenomic screens promises to rapidly advance our understanding of the molecular mechanisms underpinning pathogenesis of lymphoid malignancies. The wealth of data generated from these studies requires methods to rapidly confirm and extend findings into cell line models and primary patient samples. The proximity ligation assay (PLA) is a method that can visualize protein-protein interactions in situ. PLA can capture transient interactions and characterize constituents of stable biomolecular condensates, both of which pose technical difficulties for traditional biochemical and fluorescence imaging techniques.

Follicular lymphoma research: an open dialogue for a collaborative roadmap

Follicular lymphoma (FL) is the second most common type of lymphoma (20% of all non-Hodgkin lymphomas), derived from germinal centre (GC) B cells, and is characterised by its significant clinical, prognostic and biological heterogeneity, leading to complexity in management. Despite significant biological investigation and indisputable clinical progress since the advent of the immunotherapy era more than 20 years ago, much remains to be done to understand and cure this lymphoma. Today, FL is metaphorically a giant puzzle on the table with patches of sky, landscape and foliage clearly appearing. However, many of the remaining pieces are held by various stakeholders (e.g. clinicians, pathologists, researchers, drug developers) without global agreement on what the gaps are, or any clear blueprint on how to solve the puzzle of understanding the heterogeneity of this disease and create curative and tailored therapies. With the advent of new investigation and drug technologies, together with recent advances in our capacity to manage big data, the time seems ripe for a change of scale. More than ever, this will require collaboration between and within all stakeholders to overcome the current bottlenecks in the field. As for every investigator, we acknowledge that this first draft is necessarily biased, incomplete and some FL expert readers might recognise some remaining gaps not addressed. We hope they will reply to make this effort a collaborative one to assemble all the pieces in the most ideal fashion. As such, this review intends to be a first step and an interactive platform to a collaborative roadmap towards better understanding and care of FL.

Primary large B-cell lymphomas of immune-privileged sites

ABSTRACT

Diffuse large B-cell lymphoma (DLBCL) encompasses a diverse spectrum of aggressive B-cell lymphomas with remarkable genetic heterogeneity and myriad clinical presentations. Multiplatform genomic analyses of DLBCL have identified oncogenic drivers within genetic subtypes that allow for pathologic subclassification of tumors into discrete entities with shared immunophenotypic, genetic, and clinical features. Robust classification of lymphoid tumors establishes a foundation for precision medicine and enables the identification of novel therapeutic vulnerabilities within biologically homogeneous entities. Most cases of DLBCL involving the central nervous system (CNS), vitreous, and testis exhibit immunophenotypic features suggesting an activated B-cell (ABC) origin. Shared molecular features include frequent comutations of MYD88 (L265P) and CD79B and frequent genetic alterations promoting immune evasion, which are hallmarks of the MCD/C5/MYD88 genetic subtype of DLBCL. Clinically, these lymphomas primarily arise within anatomic sanctuary sites and have a predilection for remaining confined to extranodal sites and strong CNS tropism. Given the shared clinical and molecular features, the umbrella term primary large B-cell lymphoma of immune-privileged sites (IP-LBCL) was proposed. Other extranodal DLBCL involving the breast, adrenal glands, and skin are often ABC DLBCL but are more heterogeneous in their genomic profile and involve anatomic sites that are not considered immune privileged. In this review, we describe the overlapping clinical, pathologic, and molecular features of IP-LBCL and highlight important considerations for diagnosis, staging, and treatment. We also discuss potential therapeutic vulnerabilities of IP-LBCL including sensitivity to inhibitors of Bruton tyrosine kinase, immunomodulatory agents, and immunotherapy.

Clinicopathological characteristics and genomic profiling in patients with transformed lymphoma: a monocentric retrospective study

BACKGROUND

Transformed lymphoma occurs when indolent lymphoma transforms into more aggressive lymphoma usually associated with poor prognosis.

METHODS

In this study, we analysed the immunophenotypes, prognostic factors and outcomes of 35 patients with transformed lymphoma from among 306 marginal zone lymphoma (MZL), 544 follicular lymphoma (FL) and 871 chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL) cases. In addition, we performed whole-exome sequencing study of seven transformed MZL (tMZL) cases.

RESULTS

Our results demonstrate that the median time from indolent lymphoma diagnosis to transformed DLBCL was 35 months (range, 14-53 months). The 5-year overall survival (OS) and progression-free survival (PFS) rates after histological transformation (HT) were 50% and 26%, respectively. Kaplan-Meier survival analysis revealed that asynchronous HT and transformed CLL/SLL (tCLL/SLL) were significant adverse prognostic factors for OS after DLBCL HT. We identified mutations involvement in chromatin remodelling (CREBBP and EP300) and regulators of NF-κB signalling (TNFAIP3, BCL10, MYD88, CD79B and CARD11) were affected in tMZL.

CONCLUSION

Whole-exome sequencing and copy-number analysis revealed that tMZL derives from the divergent evolution of an ancestral common progenitor clone (CPC). Collectively, this study provides clinicopathological characteristics of three common types of transformed lymphomas and the genetic profile of tMZL with diagnostic and therapeutic implications.

Development and Validation of a Novel Four Gene-Pairs Signature for Predicting Prognosis in DLBCL Patients

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin's lymphoma. Because individual clinical outcomes of DLBCL in response to standard therapy differ widely, new treatment strategies are being investigated to improve therapeutic efficacy. In this study, we identified a novel signature for stratification of DLBCL useful for prognosis prediction and treatment selection. First, 408 prognostic gene sets were selected from approximately 2500 DLBCL samples in public databases, from which four gene-pair signatures consisting of seven prognostic genes were identified by Cox regression analysis. Then, the risk score was calculated based on these gene-pairs and we validated the risk score as a prognostic predictor for DLBCL patient outcomes. This risk score demonstrated independent predictive performance even when combined with other clinical parameters and molecular subtypes. Evaluating external DLBCL cohorts, we demonstrated that the risk-scoring model based the four gene-pair signatures leads to stable predictive performance, compared with nine existing predictive models. Finally, high-risk DLBCL showed high resistance to DNA damage caused by anticancer drugs, suggesting that this characteristic is responsible for the unfavorable prognosis of high-risk DLBCL patients. These results provide a novel index for classifying the biological characteristics of DLBCL and clearly indicate the importance of genetic analyses in the treatment of DLBCL.

A randomized trial of ibrutinib and R-GDP prior to stem cell transplant in relapsed diffuse large B-cell lymphoma

In the LY.17 randomized phase II clinical trial, adults with relapsed and refractory diffuse large B-cell lymphoma treated with ibrutinib-R-GDP (IR-GDP) for up to three cycles had more documented bacterial and fungal infections, without improvement in overall response, compared with R-GDP. CR, complete response; DLBCL, diffuse large B-cell lymphoma; PD, progressive disease; PR, partial response; R/R, relapsed/refractory; SD, stable disease.

Joint Analysis of CCAAT/Enhancer-Binding Protein Beta and Interleukin 1 Beta in the Treatment and Prognosis of Diffuse Large B-Cell Lymphoma

OBJECTIVE

The purpose of this study is to investigate the correlation between elevated levels of CCAAT/enhancer-binding protein beta (CEBPB) gene expression and unfavorable outcomes in diffuse large B-cell lymphoma (DLBCL). The goal is to elucidate potential therapeutic targets associated with this relationship.

METHODS

Differential expression and survival analyses were conducted using data from the Gene Expression Omnibus (GEO) database. The functions of CEBPB in DLBCL cells were investigated through cell culture, RNA extraction, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot. In addition, a weighted gene co-expression network analysis (WGCNA) was performed to pinpoint gene modules associated with CEBPB. Furthermore, experimental validation was carried out to explore the interaction between CEBPB and interleukin 1 beta (IL1B).

RESULTS

High levels of CEBPB expression are prominently observed in DLBCL, with its overabundance significantly linked to the diagnosis of DLBCL. Survival analysis reveals that patients exhibiting elevated CEBPB expression tend to experience a poorer prognosis. Further validation confirmed CEBPB's role in promoting DLBCL cell proliferation and cell cycle progression. WGCNA identified CEBPB-related gene modules, with IL1B identified as a potential regulatory gene of CEBPB. The presence of high levels of IL1B has been correlated with an unfavorable prognosis in individuals diagnosed with DLBCL. Experiments demonstrate that IL1B promotes DLBCL cell proliferation through CEBPB.

CONCLUSIONS

This study reveals the significant roles of CEBPB and IL1B in DLBCL, providing new theoretical foundations and potential molecular targets for the treatment and prognosis of DLBCL.

Tumor Biology Hides Novel Therapeutic Approaches to Diffuse Large B-Cell Lymphoma: A Narrative Review

Diffuse large B-cell lymphoma (DLBCL) is a malignancy of immense biological and clinical heterogeneity. Based on the transcriptomic or genomic approach, several different classification schemes have evolved over the years to subdivide DLBCL into clinically (prognostically) relevant subsets, but each leaves unclassified samples. Herein, we outline the DLBCL tumor biology behind the actual and potential drug targets and address the challenges and drawbacks coupled with their (potential) use. Therapeutic modalities are discussed, including small-molecule inhibitors, naked antibodies, antibody-drug conjugates, chimeric antigen receptors, bispecific antibodies and T-cell engagers, and immune checkpoint inhibitors. Candidate drugs explored in ongoing clinical trials are coupled with diverse toxicity issues and refractoriness to drugs. According to the literature on DLBCL, the promise for new therapeutic targets lies in epigenetic alterations, B-cell receptor and NF-κB pathways. Herein, we present putative targets hiding in lipid pathways, ferroptosis, and the gut microbiome that could be used in addition to immuno-chemotherapy to improve the general health status of DLBCL patients, thus increasing the chance of being cured. It may be time to devote more effort to exploring DLBCL metabolism to discover novel druggable targets. We also performed a bibliometric and knowledge-map analysis of the literature on DLBCL published from 2014-2023.

Targeting the Sodium-Potassium Pump as a Therapeutic Strategy in Acute Myeloid Leukemia

Tissue-specific differences in the expression of paralog genes, which are not essential in most cell types due to the buffering effect of the partner pair, can make for highly selective gene dependencies. To identify selective paralogous targets for acute myeloid leukemia (AML), we integrated the Cancer Dependency Map with numerous datasets characterizing protein-protein interactions, paralog relationships, and gene expression in cancer models. In this study, we identified ATP1B3 as a context-specific, paralog-related dependency in AML. ATP1B3, the β-subunit of the sodium-potassium pump (Na/K-ATP pump), interacts with the α-subunit ATP1A1 to form an essential complex for maintaining cellular homeostasis and membrane potential in all eukaryotic cells. When ATP1B3's paralog ATP1B1 is poorly expressed, elimination of ATP1B3 leads to the destabilization of the Na/K-ATP pump. ATP1B1 expression is regulated through epigenetic silencing in hematopoietic lineage cells through histone and DNA methylation in the promoter region. Loss of ATP1B3 in AML cells induced cell death in vitro and reduced leukemia burden in vivo, which could be rescued by stabilizing ATP1A1 through overexpression of ATP1B1. Thus, ATP1B3 is a potential therapeutic target for AML and other hematologic malignancies with low expression of ATP1B1. Significance: ATP1B3 is a lethal selective paralog dependency in acute myeloid leukemia that can be eliminated to destabilize the sodium-potassium pump, inducing cell death.

Next-Generation Integrated Sequencing Identifies Poor Prognostic Factors in Patients with MYD88-Mutated Chronic Lymphocytic Leukemia in Taiwan

INTRODUCTION

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in the Western countries and is very rare in Asia.

METHODS

Peripheral blood or bone marrow mononuclear cells obtained at initial diagnosis from 215 patients with CLL were analyzed by using next-generation sequencing to investigate the ethnic differences in genetic abnormalities.

RESULTS

Whole-genome sequencing and whole-exome sequencing analyses on 30 cases showed that 9 genes, including IGLL5, MYD88, TCHH, DSCAM, AXDND1, BICRA, KMT2D, MYT1L, and RBM43, were more frequently mutated in our Taiwanese cohort compared with those of the Western cohorts. IGLL5, MYD88, and KMT2D genes were further analyzed by targeted sequencing in another 185 CLL patients, unraveling frequencies of 29.3%, 20.9%, and 15.0%, respectively. The most frequent positional mutation of MYD88 was V217F (26/45, 57.8%), followed by L265P (9/45, 20.0%). MYD88 mutations were significantly associated with IGLL5 mutations (p = 0.0004), mutated IGHV (p < 0.0001) and 13q deletion (p = 0.0164). CLL patients with co-occurrence of MYD88 mutations with KMT2D or/and IGLL5 mutations were associated with a significantly inferior survival compared to those with MYD88 mutation alone (not reached vs. 131.8 months, p = 0.007). In multivariate analysis, MYD88 mutation without KMT2D or IGLL5 mutations was an independently favorable predictor.

CONCLUSIONS

IGLL5, MYD88, and KMT2D mutations were enriched in Taiwanese CLL, and co-occurrence of MYD88 mutations with KMT2D or/and IGLL5 mutations was associated with a poorer prognosis.

INTRODUCTION

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in the Western countries and is very rare in Asia.

METHODS

Peripheral blood or bone marrow mononuclear cells obtained at initial diagnosis from 215 patients with CLL were analyzed by using next-generation sequencing to investigate the ethnic differences in genetic abnormalities.

RESULTS

Whole-genome sequencing and whole-exome sequencing analyses on 30 cases showed that 9 genes, including IGLL5, MYD88, TCHH, DSCAM, AXDND1, BICRA, KMT2D, MYT1L, and RBM43, were more frequently mutated in our Taiwanese cohort compared with those of the Western cohorts. IGLL5, MYD88, and KMT2D genes were further analyzed by targeted sequencing in another 185 CLL patients, unraveling frequencies of 29.3%, 20.9%, and 15.0%, respectively. The most frequent positional mutation of MYD88 was V217F (26/45, 57.8%), followed by L265P (9/45, 20.0%). MYD88 mutations were significantly associated with IGLL5 mutations (p = 0.0004), mutated IGHV (p < 0.0001) and 13q deletion (p = 0.0164). CLL patients with co-occurrence of MYD88 mutations with KMT2D or/and IGLL5 mutations were associated with a significantly inferior survival compared to those with MYD88 mutation alone (not reached vs. 131.8 months, p = 0.007). In multivariate analysis, MYD88 mutation without KMT2D or IGLL5 mutations was an independently favorable predictor.

CONCLUSIONS

IGLL5, MYD88, and KMT2D mutations were enriched in Taiwanese CLL, and co-occurrence of MYD88 mutations with KMT2D or/and IGLL5 mutations was associated with a poorer prognosis.

Quantitative modeling of signaling in aggressive B cell lymphoma unveils conserved core network

B cell receptor (BCR) signaling is required for the survival and maturation of B cells and is deregulated in B cell lymphomas. While proximal BCR signaling is well studied, little is known about the crosstalk of downstream effector pathways, and a comprehensive quantitative network analysis of BCR signaling is missing. Here, we semi-quantitatively modelled BCR signaling in Burkitt lymphoma (BL) cells using systematically perturbed phosphorylation data of BL-2 and BL-41 cells. The models unveiled feedback and crosstalk structures in the BCR signaling network, including a negative crosstalk from p38 to MEK/ERK. The relevance of the crosstalk was verified for BCR and CD40 signaling in different BL cells and confirmed by global phosphoproteomics on ERK itself and known ERK target sites. Compared to the starting network, the trained network for BL-2 cells was better transferable to BL-41 cells. Moreover, the BL-2 network was also suited to model BCR signaling in Diffuse large B cell lymphoma cells lines with aberrant BCR signaling (HBL-1, OCI-LY3), indicating that BCR aberration does not cause a major downstream rewiring.

CARD14 signalosome formation is associated with its endosomal relocation and mTORC1-induced keratinocyte proliferation

Rare mutations in CARD14 promote psoriasis by inducing CARD14-BCL10-MALT1 complexes that activate NF-κB and MAP kinases. Here, the downstream signalling mechanism of the highly penetrant CARD14E138A alteration is described. In addition to BCL10 and MALT1, CARD14E138A associated with several proteins important in innate immune signalling. Interactions with M1-specific ubiquitin E3 ligase HOIP, and K63-specific ubiquitin E3 ligase TRAF6 promoted BCL10 ubiquitination and were essential for NF-κB and MAP kinase activation. In contrast, the ubiquitin binding proteins A20 and ABIN1, both genetically associated with psoriasis development, negatively regulated signalling by inducing CARD14E138A turnover. CARD14E138A localized to early endosomes and was associated with the AP2 adaptor complex. AP2 function was required for CARD14E138A activation of mTOR complex 1 (mTORC1), which stimulated keratinocyte metabolism, but not for NF-κB nor MAP kinase activation. Furthermore, rapamycin ameliorated CARD14E138A-induced keratinocyte proliferation and epidermal acanthosis in mice, suggesting that blocking mTORC1 may be therapeutically beneficial in CARD14-dependent psoriasis.

[Efficacy and safety analysis of the OR-CHOP regimen for the treatment of MCD subtype diffuse large B cell lymphoma in the real-world setting]

Objective: To investigate the efficacy and safety of orelabrutinib combined with R-CHOP in the treatment of MCD subtype diffuse large B cell lymphoma (DLBCL) . Methods: Twenty-three MCD subtype patients whose gene-subtype classification was based on baseline tumor tissue and/or baseline plasma using the LymphGen algorithm from June 2022 to June 2023 in the First Affiliated Hospital of Nanjing Medical University were retrospectively enrolled in the analysis. All patients were treated with R-CHOP or R-miniCHOP in Course 1, OR-CHOP or OR-miniCHOP (21 days for one course) in Courses 2-6, and R-monotherapy in Courses 7-8. Results: Of the 23 patients, the median age was 58 years (range: 30-81 years), and 11 (47.8% ) aged >60 years. Fifteen cases (65.2% ) had international prognostic index (IPI) scores of 3 to 5. The top 10 mutated genes in the gDNA tissues were PIM1 (78.3% ), MYD88 (69.6% ), ETV6 (43.5% ), BTG1 (39.1% ), CD79B (43.5% ), HIST1H1E (39.1% ), BTG2 (34.8% ), KMT2D (30.4% ), CD58 (26.1% ), and CDKN2B (21.7% ). The consistency rate of the tissue and plasma mutations was 80%, while the baseline plasma ctDNA burden was closely correlated with the LDH levels and IPI scores (P<0.05). All patients received 5 courses of OR-CHOP regimens. The mid-term (after 3 courses) evaluation showed that the overall response rate (ORR) was 100% (23/23), with 22 patients (95.65% ) achieving complete remission (CR), and 1 patient (4.35% ) achieving partial remission (PR). The ORR after the end of treatment (EOT) was 95.65% (22/23). Moreover, 21 patients (91.30% ) obtained CR, 1 patient (4.35% ) obtained PR, and 1 patient (4.35% ) obtained progression disease (PD). Of the 21 patients who had the dynamic EOT-ctDNA burden, only four patients (19.0% ) did not achieve EOT-ctDNA clearance, while the other 17 patients (81.0% ) achieved EOT-ctDNA clearance. The median follow-up time was 20.8 (15.3-30.0) months, while the median progression-free survival (PFS) and overall survival (OS) were not reached. The 2-year PFS rate was 71.8% (95% CI 54.7% -94.2% ), while the 2-year OS rate was 91.3% (95% CI 80.5% -100.0% ). Furthermore, the OR-CHOP regimen was generally well tolerated during clinical use, with hematological toxicity being the main adverse effect. Conclusion: This study revealed that the OR-CHOP regimen can be used as an effective and safe first-line treatment for MCD subtype DLBCL.

Molecular Determinants of Sensitivity to Polatuzumab Vedotin in Diffuse Large B-Cell Lymphoma

Polatuzumab vedotin (Pola-V) is an antibody-drug conjugate directed to the CD79B subunit of the B-cell receptor (BCR). When combined with conventional immunochemotherapy, Pola-V improves outcomes in diffuse large B-cell lymphoma (DLBCL). To identify determinants of Pola-V sensitivity, we used CRISPR-Cas9 screening for genes that modulated Pola-V toxicity for lymphomas or the surface expression of its target, CD79B. Our results reveal the striking impact of CD79B glycosylation on Pola-V epitope availability on the lymphoma cell surface and on Pola-V toxicity. Genetic, pharmacological, and enzymatic approaches that remove sialic acid from N-linked glycans enhanced lymphoma killing by Pola-V. Pola-V toxicity was also modulated by KLHL6, an E3 ubiquitin ligase that is recurrently inactivated in germinal center derived lymphomas. We reveal how KLHL6 targets CD79B for degradation in normal and malignant germinal center B cells, thereby determining expression of the surface BCR complex. Our findings suggest precision medicine strategies to optimize Pola-V as a lymphoma therapeutic. Significance: These findings unravel the molecular basis of response heterogeneity to Pola-V and identify approaches that might be deployed therapeutically to enhance the efficacy of CD79B-specific tumor killing. In addition, they reveal a novel post-translational mechanism used by normal and malignant germinal center B cells to regulate expression of the BCR. See related commentary by Leveille, p. 1577 See related article by Meriranta et al.

Disruption of KLHL6 Fuels Oncogenic Antigen Receptor Signaling in B-Cell Lymphoma

Pathomechanisms that activate oncogenic B-cell receptor (BCR) signaling in diffuse large B-cell lymphoma (DLBCL) are largely unknown. Kelch-like family member 6 (KLHL6) encoding a substrate-adapter for Cullin-3-RING E3 ubiquitin ligase with poorly established targets is recurrently mutated in DLBCL. By applying high-throughput protein interactome screens and functional characterization, we discovered that KLHL6 regulates BCR by targeting its signaling subunits CD79A and CD79B. Loss of physiologic KLHL6 expression pattern was frequent among the MCD/C5-like activated B-cell DLBCLs and was associated with higher CD79B levels and dismal outcome. Mutations in the bric-a-brac tramtrack broad domain of KLHL6 disrupted its localization and heterodimerization and increased surface BCR levels and signaling, whereas Kelch domain mutants had the opposite effect. Malfunctions of KLHL6 mutants extended beyond proximal BCR signaling with distinct phenotypes from KLHL6 silencing. Collectively, our findings uncover how recurrent mutations in KLHL6 alter BCR signaling and induce actionable phenotypic characteristics in DLBCL. Significance: Oncogenic BCR signaling sustains DLBCL cells. We discovered that Cullin-3-RING E3 ubiquitin ligase substrate-adapter KLHL6 targets BCR heterodimer (CD79A/CD79B) for ubiquitin-mediated degradation. Recurrent somatic mutations in the KLHL6 gene cause corrupt BCR signaling by disrupting surface BCR homeostasis. Loss of KLHL6 expression and mutant-induced phenotypes associate with targetable disease characteristics in B-cell lymphoma. See related commentary by Leveille et al. See related commentary by Corcoran et al.

Gα13 restricts nutrient driven proliferation in mucosal germinal centers

Germinal centers (GCs) that form in mucosal sites are exposed to gut-derived factors that have the potential to influence homeostasis independent of antigen receptor-driven selective processes. The G-protein Gα13 confines B cells to the GC and limits the development of GC-derived lymphoma. We discovered that Gα13-deficiency fuels the GC reaction via increased mTORC1 signaling and Myc protein expression specifically in the mesenteric lymph node (mLN). The competitive advantage of Gα13-deficient GC B cells (GCBs) in mLN was not dependent on T cell help or gut microbiota. Instead, Gα13-deficient GCBs were selectively dependent on dietary nutrients likely due to greater access to gut lymphatics. Specifically, we found that diet-derived glutamine supported proliferation and Myc expression in Gα13-deficient GCBs in the mLN. Thus, GC confinement limits the effects of dietary glutamine on GC dynamics in mucosal tissues. Gα13 pathway mutations coopt these processes to promote the gut tropism of aggressive lymphoma.

Exploring 2-Sulfonylpyrimidine Warheads as Acrylamide Surrogates for Targeted Covalent Inhibition: A BTK Story

Targeted covalent inhibitors (TCIs) directing cysteine have historically relied on a narrow set of electrophilic "warheads". While Michael acceptors remain at the forefront of TCI design strategies, they show variable stability and selectivity under physiological conditions. Here, we show that the 2-sulfonylpyrimidine motif is an effective replacement for the acrylamide warhead of Ibrutinib, for the inhibition of Bruton's tyrosine kinase. In a few iterations, we discovered new derivatives, which inhibit BTK both in vitro and in cellulo at low nanomolar concentrations, on par with Ibrutinib. Several derivatives also displayed good plasma stability and reduced off-target binding in vitro across 135 tyrosine kinases. This proof-of-concept study on a well-studied kinase/TCI system highlights the 2-sulfonylpyrimidine group as a useful acrylamide replacement. In the future, it will be interesting to investigate its wider potential for developing TCIs with improved pharmacologies and selectivity profiles across structurally related protein families.

ABBV-319: a CD19-targeting glucocorticoid receptor modulator antibody-drug conjugate therapy for B-cell malignancies

ABSTRACT

Glucocorticoids are key components of the standard-of-care treatment regimens for B-cell malignancy. However, systemic glucocorticoid treatment is associated with several adverse events. ABBV-319 is a CD19-targeting antibody-drug conjugate engineered to reduce glucocorticoid-associated toxicities while possessing 3 distinct mechanisms of action (MOA) to increase therapeutic efficacy: (1) antibody-mediated delivery of a glucocorticoid receptor modulator (GRM) payload to activate apoptosis, (2) inhibition of CD19 signaling, and (3) enhanced fragment crystallizable (Fc)-mediated effector function via afucosylation of the antibody backbone. ABBV-319 elicited potent GRM-driven antitumor activity against multiple malignant B-cell lines in vitro, as well as in cell line-derived xenografts and patient-derived xenografts (PDXs) in vivo. Remarkably, a single dose of ABBV-319 induced sustained tumor regression and enhanced antitumor activity compared with repeated dosing of systemic prednisolone at the maximum tolerated dose in mice. The unconjugated CD19 monoclonal antibody (mAb) also displayed antiproliferative activity in a subset of B-cell lymphoma cell lines through the inhibition of phosphoinositide 3-kinase signaling. Moreover, afucosylation of CD19 mAb enhanced Fc-mediated antibody-dependent cellular cytotoxicity. Notably, ABBV-319 displayed superior efficacy compared with afucosylated CD19 mAb in human CD34+ peripheral blood mononuclear cell-engrafted NSG-Tg(Hu-IL15) transgenic mice, demonstrating enhanced antitumor activity when multiple MOAs are enabled. ABBV-319 also showed durable antitumor activity across multiple B-cell lymphoma PDX models, including nongerminal center B-cell diffuse large B-cell lymphoma and relapsed lymphoma after R-CHOP treatment. Collectively, these data support the ongoing evaluation of ABBV-319 in a phase 1 clinical trial.

Early reappearance of intraclonal proliferative subpopulations in ibrutinib-resistant chronic lymphocytic leukemia

The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib represents an effective strategy for treatment of chronic lymphocytic leukemia (CLL), nevertheless about 30% of patients eventually undergo disease progression. Here we investigated by flow cytometry the long-term modulation of the CLL CXCR4dim/CD5bright proliferative fraction (PF), its correlation with therapeutic outcome and emergence of ibrutinib resistance. By longitudinal tracking, the PF, initially suppressed by ibrutinib, reappeared upon early disease progression, without association with lymphocyte count or serum beta-2-microglobulin. Somatic mutations of BTK/PLCG2, detected in 57% of progressing cases, were significantly enriched in PF with a 3-fold greater allele frequency than the non-PF fraction, suggesting a BTK/PLCG2-mutated reservoir resident within the proliferative compartments. PF increase was also present in BTK/PLCG2-unmutated cases at progression, indicating that PF evaluation could represent a marker of CLL progression under ibrutinib. Furthermore, we evidence different transcriptomic profiles of PF at progression in cases with or without BTK/PLCG2 mutations, suggestive of a reactivation of B-cell receptor signaling or the emergence of bypass signaling through MYC and/or Toll-Like-Receptor-9. Clinically, longitudinal monitoring of the CXCR4dim/CD5bright PF by flow cytometry may provide a simple tool helping to intercept CLL progression under ibrutinib therapy.

First-in-class inhibitor of HSP110 blocks BCR activation through SYK phosphorylation in diffuse large B-cell lymphoma

Activated B-cell-like diffuse large B-cell lymphoma (ABC-DLBCL) is driven by aberrant activation of the B-cell receptor (BCR) and the TLR/MyD88 signaling pathways. The heat-shock protein HSP110 is a candidate for their regulation as it stabilizes MyD88. However, its role in overall BCR signaling remains unknown. Here, we used first-in-class HSP110 inhibitors to address this question. HSP110 inhibitors decreased the survival of several ABC-DLBCL cell lines in vitro and in vivo, and reduced the phosphorylation of BCR signaling kinases, including BTK and SYK. We identified an interaction between HSP110 and SYK and demonstrated that HSP110 promotes SYK phosphorylation. Finally, the combination of the HSP110 inhibitor with the PI3K inhibitor copanlisib decreases SYK/BTK and AKT phosphorylation synergistically, leading to suppression of tumor growth in cell line xenografts and strong reduction in patient-derived xenografts. In conclusion, by regulating the BCR/TLR signaling pathway, HSP110 inhibitors are potential drug candidates for ABC-DLBCL patients.

Antibody-drug conjugates in cancer therapy: mechanisms and clinical studies

Antibody-drug conjugates (ADCs) consist of monoclonal antibodies that target tumor cells and cytotoxic drugs linked through linkers. By leveraging antibodies' targeting properties, ADCs deliver cytotoxic drugs into tumor cells via endocytosis after identifying the tumor antigen. This precise method aims to kill tumor cells selectively while minimizing harm to normal cells, offering safe and effective therapeutic benefits. Recent years have seen significant progress in antitumor treatment with ADC development, providing patients with new and potent treatment options. With over 300 ADCs explored for various tumor indications and some already approved for clinical use, challenges such as resistance due to factors like antigen expression, ADC processing, and payload have emerged. This review aims to outline the history of ADC development, their structure, mechanism of action, recent composition advancements, target selection, completed and ongoing clinical trials, resistance mechanisms, and intervention strategies. Additionally, it will delve into the potential of ADCs with novel markers, linkers, payloads, and innovative action mechanisms to enhance cancer treatment options. The evolution of ADCs has also led to the emergence of combination therapy as a new therapeutic approach to improve drug efficacy.

Traffic control on the toll road

In B cells, TRAF3 plays a central role in regulating the B cell receptor and the toll-like receptor signaling cascade by inhibiting Syk phospohorylation as well as its localization to the Myddosome.

IRF4 requires ARID1A to establish plasma cell identity in multiple myeloma

Multiple myeloma (MM) is an incurable plasma cell malignancy that exploits transcriptional networks driven by IRF4. We employ a multi-omics approach to discover IRF4 vulnerabilities, integrating functional genomics screening, spatial proteomics, and global chromatin mapping. ARID1A, a member of the SWI/SNF chromatin remodeling complex, is required for IRF4 expression and functionally associates with IRF4 protein on chromatin. Deleting Arid1a in activated murine B cells disrupts IRF4-dependent transcriptional networks and blocks plasma cell differentiation. Targeting SWI/SNF activity leads to rapid loss of IRF4-target gene expression and quenches global amplification of oncogenic gene expression by MYC, resulting in profound toxicity to MM cells. Notably, MM patients with aggressive disease bear the signature of SWI/SNF activity, and SMARCA2/4 inhibitors remain effective in immunomodulatory drug (IMiD)-resistant MM cells. Moreover, combinations of SWI/SNF and MEK inhibitors demonstrate synergistic toxicity to MM cells, providing a promising strategy for relapsed/refractory disease.

Inhibition of MALT1 and BCL2 Induces Synergistic Antitumor Activity in Models of B-Cell Lymphoma

The activated B cell (ABC) subset of diffuse large B-cell lymphoma (DLBCL) is characterized by chronic B-cell receptor signaling and associated with poor outcomes when treated with standard therapy. In ABC-DLBCL, MALT1 is a core enzyme that is constitutively activated by stimulation of the B-cell receptor or gain-of-function mutations in upstream components of the signaling pathway, making it an attractive therapeutic target. We discovered a novel small-molecule inhibitor, ABBV-MALT1, that potently shuts down B-cell signaling selectively in ABC-DLBCL preclinical models leading to potent cell growth and xenograft inhibition. We also identified a rational combination partner for ABBV-MALT1 in the BCL2 inhibitor, venetoclax, which when combined significantly synergizes to elicit deep and durable responses in preclinical models. This work highlights the potential of ABBV-MALT1 monotherapy and combination with venetoclax as effective treatment options for patients with ABC-DLBCL.

Combination Targeted Therapy in Relapsed Diffuse Large B-Cell Lymphoma

BACKGROUND

The identification of oncogenic mutations in diffuse large B-cell lymphoma (DLBCL) has led to the development of drugs that target essential survival pathways, but whether targeting multiple survival pathways may be curative in DLBCL is unknown.

METHODS

We performed a single-center, phase 1b-2 study of a regimen of venetoclax, ibrutinib, prednisone, obinutuzumab, and lenalidomide (ViPOR) in relapsed or refractory DLBCL. In phase 1b, which included patients with DLBCL and indolent lymphomas, four dose levels of venetoclax were evaluated to identify the recommended phase 2 dose, with fixed doses of the other four drugs. A phase 2 expansion in patients with germinal-center B-cell (GCB) and non-GCB DLBCL was performed. ViPOR was administered every 21 days for six cycles.

RESULTS

In phase 1b of the study, involving 20 patients (10 with DLBCL), a single dose-limiting toxic effect of grade 3 intracranial hemorrhage occurred, a result that established venetoclax at a dose of 800 mg as the recommended phase 2 dose. Phase 2 included 40 patients with DLBCL. Toxic effects that were observed among all the patients included grade 3 or 4 neutropenia (in 24% of the cycles), thrombocytopenia (in 23%), anemia (in 7%), and febrile neutropenia (in 1%). Objective responses occurred in 54% of 48 evaluable patients with DLBCL, and complete responses occurred in 38%; complete responses were exclusively in patients with non-GCB DLBCL and high-grade B-cell lymphoma with rearrangements of MYC and BCL2 or BCL6 (or both). Circulating tumor DNA was undetectable in 33% of the patients at the end of ViPOR therapy. With a median follow-up of 40 months, 2-year progression-free survival and overall survival were 34% (95% confidence interval [CI], 21 to 47) and 36% (95% CI, 23 to 49), respectively.

CONCLUSIONS

Treatment with ViPOR was associated with durable remissions in patients with specific molecular DLBCL subtypes and was associated with mainly reversible adverse events. (Funded by the Intramural Research Program of the National Cancer Institute and the National Center for Advancing Translational Sciences of the National Institutes of Health and others; ClinicalTrials.gov number, NCT03223610.).

Molecular Subtypes and the Role of TP53 in Diffuse Large B-Cell Lymphoma and Richter Syndrome

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoid malignancy and a heterogeneous entity comprised of several biologically distinct subtypes. Recently, novel genetic classifications of DLBCL have been resolved based on common mutational patterns indicative of distinct pathways of transformation. However, the complicated and costly nature of the novel classifiers has precluded their inclusion into routine practice. In view of this, the status of the TP53 gene, which is mutated or deleted in 20-30% of the cases, has emerged as an important prognostic factor for DLBCL patients, setting itself apart from other predictors. TP53 genetic lesions are particularly enriched in a genetic subtype of DLBCL that shares genomic features with Richter Syndrome, highlighting the possibility of a subset of DLBCL arising from the transformation of an occult chronic lymphocytic leukemia-like malignancy, such as monoclonal B-cell lymphocytosis. Patients with TP53-mutated DLBCL, including those with Richter Syndrome, have a particularly poor prognosis and display inferior responses to standard chemoimmunotherapy regimens. The data presented in this manuscript argue for the need for improved and more practical risk-stratification models for patients with DLBCL and show the potential for the use of TP53 mutational status for prognostication and, in prospect, treatment stratification in DLBCL.