Molecular pathogenesis of mantle cell lymphoma

UiO-66 MOFs-Based "Epi-Nano-Sonosensitizer" for Ultrasound-Driven Cascade Immunotherapy against B-Cell Lymphoma

B-cell lymphoma (BCL) is a hematological malignancy with high heterogeneity and represents an aggressive proliferation of mature B-cells. Despite the initial success of traditional treatments for BCL in clinical trials, a majority of patients eventually develop resistance to therapy and have poor clinical outcomes. Epigenetic dysregulation is a major contributor to the pathogenesis of BCL, and therapies targeting epigenetic pathways is a promising alternative strategy for treating BCL. Herein, we developed a metal-organic framework (MOF)-based nano-sonosensitizer for ultrasound-driven cascade immunotherapy against BCL. The nano-sonosensitizer was synthesized by encapsulating copper complex of the m6A-mRNA demethylase inhibitor into UiO-66-NH2, which possesses a Z-scheme heterostructure and allows efficient electron-hole pair separation for generating reactive oxygen species (ROS) under ultrasound activation. These CuR@UiO66 sonosensitizers were functionalized with mPEG-PO3 and anti-CD19 antibody, and the resulting CRUPPA19 particles could specifically accumulate in the BCL tissue and also target lymphoma cells that infiltrated into the bone marrow. Once internalized, CRUPPA19 could induce intracellular ROS production and apoptosis under ultrasound irradiation. Subsequently, ultrasonic stimulation triggered autophagy-mediated release of Cu and Rhein from CRUPPA19, thereby increasing protein lipoylation and global mRNA methylation, which led to cuproptosis and the transcriptional repression PDL1, respectively. These cascades synergistically induced immunogenic cell death in the tumors and promoted activation of CD8+ T cells, eventually leading to an antilymphoma immune response. CRUPPA19-mediated sono-immunotherapy not only eliminated the primary and metastatic lymphomas but also cleared lymphoma cells from the bone marrow. This study provided an insight into a MOF-based nanoepigenetic therapy platform with ultrasound-triggered cascade amplification for enhanced antihematological tumor immunity.

Zanubrutinib, obinutuzumab, and venetoclax for first-line treatment of mantle cell lymphoma with a TP53 mutation

ABSTRACT

TP53-mutant mantle cell lymphoma (MCL) is associated with poor survival outcomes with standard chemoimmunotherapy. We conducted a multicenter, phase 2 study of zanubrutinib, obinutuzumab, and venetoclax (BOVen) in untreated patients with MCL with a TP53 mutation. Patients initially received 160 mg zanubrutinib twice daily and obinutuzumab. Obinutuzumab at a dose of 1000 mg was given on cycle 1 day 1, 8, and 15, and on day 1 of cycles 2 to 8. After 2 cycles, venetoclax was added with weekly dose ramp-up to 400 mg daily. After 24 cycles, if patients were in complete remission with undetectable minimal residual disease (uMRD) using an immunosequencing assay, treatment was discontinued. The primary end point was met if ≥11 patients were progression free at 2 years. The study included 25 patients with untreated MCL with a TP53 mutation. The best overall response rate was 96% (24/25) and the complete response rate was 88% (22/25). Frequency of uMRD at a sensitivity level of 1 × 10-5 and uMRD at a sensitivity level of 1 × 10-6 at cycle 13 was 95% (18/19) and 84% (16/19), respectively. With a median follow-up of 28.2 months, the 2-year progression-free, disease-specific, and overall survival were 72%, 91%, and 76%, respectively. Common side effects were generally low grade and included diarrhea (64%), neutropenia (32%), and infusion-related reactions (24%). BOVen was well tolerated and met its primary efficacy end point in TP53-mutant MCL. These data support its use and ongoing evaluation. This trial was registered at www.ClinicalTrials.gov as #NCT03824483.

SQSTM1/p62 predicts prognosis and upregulates the transcription of CCND1 to promote proliferation in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare, highly invasive non-Hodgkin's lymphoma. The main pathogenesis of MCL is associated with the formation of the IgH/CCND1 fusion gene and nuclear overexpression of cyclin D1, which accelerates the cell cycle, leading to tumorigenesis. The prognosis with current standard chemotherapy is still unsatisfactory. SQSTM1/p62 is a multifunctional adaptor that plays an important role in various tumors. Here, we found that the expression of p62 in MCL tissues was higher than that in hyperplastic lymphadenitis patients. Patients with low p62 expression in MCL cells had better overall survival and progression-free survival rates than those with high expression (p = 0.024 and p = 0.025, respectively). Multivariate Cox analysis indicated that the calculated death risk (hazard ratio [HR]) in patients with high expression levels of p62 increased to 2.742 (95% confidence interval (CI) of 1.268-5.852, p = 0.01), which was higher than those with low levels. Silencing p62 impaired Jeko-1 and Granta519 cell proliferation while downregulating CCND1 mRNA and protein expression, thereby inducing G0/G1 cell cycle arrest. However, silencing p62 does not affect the fusion of IgH and CCND1. Luciferase reporter gene analysis and chromatin immunoprecipitation analysis demonstrated that p62 may regulate CCND1 gene expression through Nrf2. These results provide evidence that p62 can predict poor prognosis in MCL. The precise targeting of p62 therapy reduces the promoting effect of Nrf2 on CCND1, thereby preventing cell cycle progression and effectively inhibiting tumor proliferation. Therefore, p62 may provide a potential target for MCL.

A comprehensive review on the current status of CRISPR based clinical trials for rare diseases

A considerable fraction of population in the world suffers from rare diseases. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and its related Cas proteins offer a modern form of curative gene therapy for treating the rare diseases. Hereditary transthyretin amyloidosis, hereditary angioedema, duchenne muscular dystrophy and Rett syndrome are a few examples of such rare diseases. CRISPR/Cas9, for example, has been used in the treatment of β-thalassemia and sickle cell disease (Frangoul et al., 2021; Pavani et al., 2021) [1,2]. Neurological diseases such as Huntington's have also been focused in some studies involving CRISPR/Cas (Yang et al., 2017; Yan et al., 2023) [3,4]. Delivery of these biologicals via vector and non vector mediated methods depends on the type of target cells, characteristics of expression, time duration of expression, size of foreign genetic material etc. For instance, retroviruses find their applicability in case of ex vivo delivery in somatic cells due to their ability to integrate in the host genome. These have been successfully used in gene therapy involving X-SCID patients although, incidence of inappropriate activation has been reported. On the other hand, ex vivo gene therapy for β-thalassemia involved use of BB305 lentiviral vector for high level expression of CRISPR biological in HSCs. The efficacy and safety of these biologicals will decide their future application as efficient genome editing tools as they go forward in further stages of human clinical trials. This review focuses on CRISPR/Cas based therapies which are at various stages of clinical trials for treatment of rare diseases and the constraints and ethical issues associated with them.

Disruption of cyclin D1 degradation leads to the development of mantle cell lymphoma

Cyclin D1 has been recognized as an oncogene due to its abnormal upregulation in different types of cancers. Here, we demonstrated that cyclin D1 is SUMOylated, and we identified Itch as a specific E3 ligase recognizing SUMOylated cyclin D1 and mediating SUMO-induced ubiquitination and proteasome degradation of cyclin D1. We generated cyclin D1 mutant mice with mutations in the SUMOylation site, phosphorylation site, or both sites of cyclin D1, and found that double mutant mice developed a Mantle cell lymphoma (MCL)-like phenotype. We showed that arsenic trioxide (ATO) enhances cyclin D1 SUMOylation-mediated degradation through inhibition of cyclin D1 deSUMOylation enzymes, leading to MCL cell apoptosis. Treatment of severe combined immunodeficiency (SCID) mice grafted with MCL cells with ATO resulted in a significant reduction in tumor growth. In this study, we provide novel insights into the mechanisms of MCL tumor development and cyclin D1 regulation and discover a new strategy for MCL treatment.

Mantle Cell Lymphoma Under the Scope of Personalized Medicine: Perspective and Directions

Mantle cell lymphoma (MCL) is a rare, incurable non-Hodgkin's lymphoma characterized by naive B cells infiltrating the lymphoid follicle's mantle zone. A key feature of MCL is the cytogenetic abnormality t(11;14) (q13:q14), found in 95% of cases, leading to Cyclin D1 overexpression resulting in uncontrolled cell cycle progression and genetic instability. Occasionally, Cyclin D2 or D3 overexpression can substitute for Cyclin D1, causing similar effects. The transcription factor SOX11 is a hallmark of classical Cyclin D1-positive MCL and also in cases without the typical t(11;14) abnormality, making it an important diagnostic marker. MCL's development necessitates secondary genetic changes, including mutations in the ATM, TP53, and NOTCH1 genes, with the TP53 mutation being the only genetic biomarker with established clinical prognostic value. The Mantle Cell Lymphoma International Prognostic Index (MIPI) score, which considers age, performance status, serum LDH levels, and leukocyte count, stratifies patients into risk groups. Histologic variants of MCL, such as classic, blastoid, and pleomorphic, offer additional prognostic information. Recent research highlights new mutations potentially tied to specific populations among MCL patients, suggesting the benefit of personalized management for better predicting outcomes like progression-free survival. This approach could lead to more effective, risk-adapted treatment strategies. However, challenges remain in patient stratification and in developing new therapeutic targets for MCL. This review synthesizes current knowledge on genetic mutations in MCL and their impact on prognosis. It aims to explore the prognostic value of genetic markers related to population traits, emphasizing the importance of tailored molecular medicine in MCL.

B-cell non-Hodgkin lymphomas

B-cell lymphomas occur with an incidence of 20 new cases per 100 000 people per year in high-income countries. They can affect any organ and are characterised by heterogeneous clinical presentations and courses, varying from asymptomatic, to indolent, to very aggressive cases. Since the topic of B-cell non-Hodgkin lymphomas was last reviewed in The Lancet in 2017, a deeper understanding of the biological background of this heterogeneous group of malignancies, the availability of new diagnostic methods, and the development and implementation of new targeted and immunotherapeutic approaches have improved our ability to treat patients. This Seminar provides an overview of the pathobiology, classification, and prognostication of B-cell non-Hodgkin lymphomas and summarises the current knowledge and standard of care regarding biology and clinical management of the most common subtypes of mature B-cell non-Hodgkin lymphomas. It also highlights new findings in deciphering the molecular background of disease development and the implementation of new therapeutic approaches, particularly those targeting the immune system.

Targeting DNMT3A-mediated oxidative phosphorylation to overcome ibrutinib resistance in mantle cell lymphoma

The use of Bruton tyrosine kinase (BTK) inhibitors such as ibrutinib achieves a remarkable clinical response in mantle cell lymphoma (MCL). Acquired drug resistance, however, is significant and affects long-term survival of MCL patients. Here, we demonstrate that DNA methyltransferase 3A (DNMT3A) is involved in ibrutinib resistance. We find that DNMT3A expression is upregulated upon ibrutinib treatment in ibrutinib-resistant MCL cells. Genetic and pharmacological analyses reveal that DNMT3A mediates ibrutinib resistance independent of its DNA-methylation function. Mechanistically, DNMT3A induces the expression of MYC target genes through interaction with the transcription factors MEF2B and MYC, thus mediating metabolic reprogramming to oxidative phosphorylation (OXPHOS). Targeting DNMT3A with low-dose decitabine inhibits the growth of ibrutinib-resistant lymphoma cells both in vitro and in a patient-derived xenograft mouse model. These findings suggest that targeting DNMT3A-mediated metabolic reprogramming to OXPHOS with decitabine provides a potential therapeutic strategy to overcome ibrutinib resistance in relapsed/refractory MCL.

Drug-Loaded Biomimetic Carriers for Non-Hodgkin's Lymphoma Therapy: Advances and Perspective

Chemotherapy remains the mainstay of treatment for the lymphoma patient population, despite its relatively poor therapeutic results, high toxicity, and low specificity. With the advancement of biotechnology, the significance of drug-loading biomimetic materials in the medical field has become increasingly evident, attracting extensive attention from the scientific community and the pharmaceutical industry. Given that they can cater to the particular requirements of lymphoma patients, drug-loading biomimetic materials have recently become a potent and promising delivery approach for various applications. This review mainly reviews the recent advancements in the treatment of tumors with biological drug carrier-loaded drugs, outlines the mechanisms of lymphoma development and the diverse treatment modalities currently available, and discusses the merits and limitations of biological drug carriers. What is more, the practical application of biocarriers in tumors is explored by providing examples, and the possibility of loading such organisms with antilymphoma drugs for the treatment of lymphoma is conceived.

Letting the mantle out of the bag

Mantle cell lymphoma is a rare disease that attracts the curiosity of clinicians and scientists due to its heterogeneous clinical behaviour, that can vary from indolent forms to the most aggressive presentations among non-Hodgkin lymphomas. The report by Eyre and colleagues describes the current treatment strategies available in most countries, and offers insights to clinicians for several intriguing difficult-to-treat scenarios. Commentary on: Eyre et al. Diagnosis and management of mantle cell lymphoma: a British Society for Haematology Guideline. Br J Haematol 2024;204:108-126.

LC-PDA-QTof-MS characterization of the stress degradation products of Zanubrutinib: A novel BTK inhibitor

Zanubrutinib (ZAN) is an orally administered anti-cancer medication used for the treatment of Mantle cell lymphoma. Recently, it has also been approved by FDA for the treatment of chronic lymphocytic leukemia. Determination of impurities formed in drug substances/products as a result of manufacturing or storage forms an important aspect of drug life cycle management. The current study concentrated on understanding the stability of ZAN under various stress conditions as per the ICH Q1 (R2) guidelines. In total, ZAN produced thirteen degradation products under various hydrolytic (acid, base and neutral) and thermal stress conditions. The stress degradation products were separated by ultra-performance liquid chromatography, chemical structures of these products were characterized by MS/MS experiments combined with accurate mass measurements conducted on a LC-QTof-MS. The mechanism for the formation of these degradation products was also proposed. This study provides comprehensive information on the inherent stability of ZAN which will be useful in the drug development and manufacturing processes.

Inhibition of a new AXL isoform, AXL3, induces apoptosis of mantle cell lymphoma cells

Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma having a poor overall survival that is in need for the development of new therapeutics. In this study, we report the identification and expression of a new isoform splice variant of the tyrosine kinase receptor AXL in MCL cells. This new AXL isoform, called AXL3, lacks the ligand-binding domain of the commonly described AXL splice variants and is constitutively activated in MCL cells. Interestingly, functional characterization of AXL3, using CRISPR inhibition, revealed that only the knock down of this isoform leads to apoptosis of MCL cells. Importantly, pharmacological inhibition of AXL activity resulted in a significant decrease in the activation of well-known proproliferative and survival pathways activated in MCL cells (ie, β-catenin, Ak strain transforming, and NF-κB). Therapeutically, preclinical studies using a xenograft mouse model of MCL indicated that bemcentinib is more effective than ibrutinib in reducing the tumor burden and to increase the overall survival. Our study highlights the importance of a previously unidentified AXL splice variant in cancer and the potential of bemcentinib as a targeted therapy for MCL.

Combating relapsed and refractory Mantle cell lymphoma with novel therapeutic armamentarium: Recent advances and clinical prospects

Mantle cell lymphoma (MCL) is a rare, aggressive subtype of non-Hodgkin's lymphoma (NHL), accounting for 5% of all cases. Due to its virulence factor, it is an incurable disease and keeps relapsing despite an intensive treatment regimen. Advancements in research and drug discovery have shifted the treatment strategy from conventional chemotherapy to targeted agents and immunotherapies. The establishment of the role of Bruton tyrosine kinase led to the development of ibrutinib, a first-generation BTK inhibitor, and its successors. A conditioning regimen based immunotherapeutic agent like ibritumumob, has also demonstrated a viable response with a favorable toxicity profile. Brexucabtagene Autoleucel, the only approved CAR T-cell therapy, has proven advantageous for relapsed/refractory MCL in both children and adults. This article reviews certain therapies that could help update the current approach and summarizes a few miscellaneous agents, which, seldom studied in trials, could alleviate the regression observed in traditional therapies. DATA AVAILABILITY: The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

CCND1-associated ceRNA network reveal the critical pathway of TPRG1-AS1-hsa-miR-363-3p-MYO1B as a prognostic marker for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSC) is one of the leading causes of cancer death globally, yet there are few useful biomarkers for early identification and prognostic prediction. Previous studies have confirmed that CCND1 amplification is closely associated with head and neck oncogenesis, and the present study explored the ceRNA network associated with CCND1. Gene expression profiling of the Head and Neck Squamous Cell Carcinoma (HNSC) project of The Cancer Genome Atlas (TCGA) program identified the TPRG1-AS1-hsa-miR-363-3P-MYO1B gene regulatory axis associated with CCND1. Further analysis of the database showed that MYOB was regulated by methylation in head and neck tumors, and functional enrichment analysis showed that MYO1B was involved in "actin filament organization" and "cadherin binding ". Immune infiltration analysis suggested that MYO1B may influence tumorigenesis and prognosis by regulating the immune microenvironment of HNSC. MYO1B enhanced tumor spread through the EMT approach, according to epithelial mesenchymal transition (EMT) characterisation. We analyzed both herbal and GSCALite databases and found that CCND1 and MYO1B have the potential as predictive biomarkers for the treatment of HNSC patients. RT-qPCR validated bioinformatic predictions of gene expression in vitro cell lines. In conclusion, we found a CCND1-related ceRNA network and identified the novel TPRG1-AS1-hsa-miR-363-3p-MYO1B pathway as a possible HNSC diagnostic biomarker and therapeutic target.

Mantle cell lymphoma-Update on molecular biology, prognostication and treatment approaches

Mantle cell lymphoma (MCL) is clinically characterized by its heterogenous behavior with courses ranging from indolent cases that do not require therapy for years to highly aggressive MCL with very limited prognosis. The development and implementation of new targeted and immunotherapeutic approaches have already improved therapeutic options especially for refractory or relapsed disease. Nevertheless, to further optimize MCL treatment, early identification of individual risk profile and risk-adapted, patient-tailored choice of therapeutic strategy needs to be prospectively incorporated in clinical patient management. This review summarizes the current knowledge and standard of care regarding biology and clinical management of MCL, highlighting the implementation of new therapeutic approaches especially targeting the immune system.

Prognostic Role of CDKN2A Deletion and p53 Expression and Association With MIPIb in Mantle Cell Lymphoma

INTRODUCTION

Mantle cell lymphoma (MCL) is a rare type of lymphoma, which despite improvements in therapies in recent decades, remains an incurable disease. There is currently no reliable marker of chemoresistance available. In this study, we investigated the prognostic role of MIPIb and the association with biological markers including SOX11, p53 expression, Ki-67, and CDKN2A.

MATERIALS AND METHODS

This retrospective study was focused on 23 patients with newly diagnosed classical MCL, treated at the University Hospital of Bari (Italy) between January 2006 and June 2019.

RESULTS

We identified a MIPIb value ≥ 5.4440 as a prognostic parameter that correlates with p53 expression and CDKN2A deletion. We also observed that patients with p53 overexpression had a significantly higher MIPIb (5.52 ± 0.53) which in 80% of patients had a value higher than 5.4440. On the other hand, CDKN2A deletion was found more frequently (75%) associated with MIPIb ≥5.4440. Only the CDKN2A deletion was associated with a higher proliferation index, with 66.7% of samples having Ki67 ≥30%. From the survival analysis we found that patients with p53 overexpression and CDKN2A deletion have a significantly worse prognosis with a median overall survival of 50 (P = .012) and 52 months (P = .018), respectively.

CONCLUSION

p53 expression and CDKN2A deletion represent a reliable pretreatment prognostic factor that identifies patients who do not benefit from currently used immunochemotherapy-based therapies and who are candidates for diversified treatments with the aim of improving prognosis. The MIPIb represents a prognostic index that correlates well with these biological alterations and can be used in clinical practice as their surrogate.

A novel patient-derived 3D model recapitulates mantle cell lymphoma lymph node signaling, immune profile and in vivo ibrutinib responses

Mantle cell lymphoma (MCL), a rare and aggressive B-cell non-Hodgkin lymphoma, mainly develops in the lymph node (LN) and creates a protective and immunosuppressive niche that facilitates tumor survival, proliferation and chemoresistance. To capture disease heterogeneity and tumor microenvironment (TME) cues, we have developed the first patient-derived MCL spheroids (MCL-PDLS) that recapitulate tumor oncogenic pathways and immune microenvironment in a multiplexed system that allows easy drug screening, including immunotherapies. MCL spheroids, integrated by tumor B cells, monocytes and autologous T-cells self-organize in disc-shaped structures, where B and T-cells maintain viability and proliferate, and monocytes differentiate into M2-like macrophages. RNA-seq analysis demonstrated that tumor cells recapitulate hallmarks of MCL-LN (proliferation, NF-kB and BCR), with T cells exhibiting an exhaustion profile (PD1, TIM-3 and TIGIT). MCL-PDLS reproduces in vivo responses to ibrutinib and demonstrates that combination of ibrutinib with nivolumab (anti-PD1) may be effective in ibrutinib-resistant cases by engaging an immune response with increased interferon gamma and granzyme B release. In conclusion, MCL-PDLS recapitulates specific MCL-LN features and in vivo responses to ibrutinib, representing a robust tool to study MCL interaction with the immune TME and to perform drug screening in a patient-derived system, advancing toward personalized therapeutic approaches.

Roles of PI3Kγ and PI3Kδ in mantle cell lymphoma proliferation and migration contributing to efficacy of the PI3Kγ/δ inhibitor duvelisib

Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma that is incurable with existing therapies, and therefore presents a significant unmet clinical need. The ability of this disease to overcome therapy, including those that target the B cell receptor pathway which has a pathogenic role in MCL, highlights the need to develop new treatment strategies. Herein, we demonstrate that a distinguishing feature of lymph node resident MCL cells is the expression of phosphatidylinositol 3-kinase γ (PI3Kγ), a PI3K isoform that is not highly expressed in other B cells or B-cell malignancies. By exploring the role of PI3K in MCL using different PI3K isoform inhibitors, we provide evidence that duvelisib, a dual PI3Kδ/γ inhibitor, has a greater effect than PI3Kδ- and PI3Kγ-selective inhibitors in blocking the proliferation of primary MCL cells and MCL cell lines, and in inhibiting tumour growth in a mouse xenograft model. In addition, we demonstrated that PI3Kδ/γ signalling is critical for migration of primary MCL cells and cell lines. Our data indicates that aberrant expression of PI3Kγ is a critical feature of MCL pathogenesis. Thus, we suggest that the dual PI3Kδ/γ duvelisib would be effective for the treatment of mantle cell lymphoma.

Inhibition of casein kinase 2 sensitizes mantle cell lymphoma to venetoclax through MCL-1 downregulation

BCL-2 family proteins are frequently aberrantly expressed in mantle cell lymphoma (MCL). Recently, the BCL-2-specific inhibitor venetoclax has been approved by the US Food and Drug Administration for chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML). In MCL, venetoclax has shown promising efficacy in early clinical trials; however, a significant subset of patients is resistant. By conducting a kinome-centered CRISPR-Cas9 knockout sensitizer screen, we identified casein kinase 2 (CK2) as a major regulator of venetoclax resistance in MCL. Interestingly, CK2 is over-expressed in MCL and high CK2 expression is associated with poor patient survival. Targeting of CK2, either by inducible short hairpin RNA (shRNA)-mediated knockdown of CK2 or by the CK2-inhibitor silmitasertib, did not affect cell viability by itself, but strongly synergized with venetoclax in both MCL cell lines and primary samples, also if combined with ibrutinib. Furthermore, targeting of CK2 reduced MCL-1 levels, which involved impaired MCL-1 translation by inhibition of eIF4F complex assembly, without affecting BCL-2 and BCL-XL expression. Combined, this results in enhanced BCL-2 dependence and, consequently, venetoclax sensitization. In cocultures, targeting of CK2 overcame stroma-mediated venetoclax resistance of MCL cells. Taken together, our findings indicate that targeting of CK2 sensitizes MCL cells to venetoclax through downregulation of MCL-1. These novel insights provide a strong rationale for combining venetoclax with CK2 inhibition as therapeutic strategy for MCL patients.

Immunohistochemical analysis of arachidonate 5-lipoxygenase expression in B-cell lymphomas: Implication for B cell differentiation and its analogy with lymphomagenesis

Arachidonate 5-lipoxygenase (ALOX5) is a cardinal enzyme in the synthesis of leukotrienes, which are powerful immune-regulating lipid mediators. We previously reported that ALOX5 is preferentially expressed in B lymphocytes in the mantle zone of human lymphoid tissue. In the context of physiological relevance, the loss of the Alox5 gene in mice significantly impairs the development of follicular B helper T cells and antibody production. However, ALOX5 expression in B-cell lymphomas has not been investigated in detail. In this study, we examined ALOX5 expression in representative B-cell lymphomas and non-neoplastic lymphoid tissues by immunohistochemistry with a commercially available anti-ALOX5 antibody that can be used on formalin-fixed paraffin-embedded specimens. Interestingly, 22/22 cases of mantle cell lymphoma, 7/7 cases of chronic lymphocytic leukemia/small cell lymphoma, and 20/20 cases of follicular lymphoma expressed ALOX5. A small proportion of extranodal marginal zone lymphoma/mucosa-associated lymphoid tissue lymphoma or nodal marginal zone lymphoma cases were positive for ALOX5 (2/13 or 1/3, respectively). In contrast, no cases with diffuse large B-cell lymphoma, regardless of germinal center B cell (GCB) or non-GCB type, expressed ALOX5 (0/25 cases). These findings suggest that ALOX5 may be a novel marker for identifying the cell of origin of B-cell lymphoma. Further investigation is required to clarify the biological significance of ALOX5 expression in lymphoma cells.

Tumorigenic role of Musashi-2 in aggressive mantle cell lymphoma

SOX11 overexpression has been associated with aggressive behavior of mantle cell lymphomas (MCL). SOX11 is overexpressed in embryonic and cancer stem cells (CSC) of some tumors. Although CSC have been isolated from primary MCL, their relationship to SOX11 expression and contribution to MCL pathogenesis and clinical evolution remain unknown. Here, we observed enrichment in leukemic and hematopoietic stem cells gene signatures in SOX11+ compared to SOX11- MCL primary cases. Musashi-2 (MSI2) emerged as one of the most significant upregulated stem cell-related genes in SOX11+ MCLs. SOX11 is directly bound to the MSI2 promoter upregulating its expression in vitro. MSI2 intronic enhancers were strongly activated in SOX11+ MCL cell lines and primary cases. MSI2 upregulation was significantly associated with poor overall survival independently of other high-risk features of MCL. MSI2 knockdown decreased the expression of genes related to apoptosis and stem cell features and significantly reduced clonogenic growth, tumor cell survival and chemoresistance in MCL cells. MSI2-knockdown cells had reduced tumorigenic engraftment into mice bone marrow and spleen compared to control cells in xenotransplanted mouse models. Our results suggest that MSI2 might play a key role in sustaining stemness and tumor cell survival, representing a possible novel target for therapeutic interventions in MCL.

Ibrutinib as monotherapy versus combination therapy in Chinese patients with relapsed/refractory mantle cell lymphoma: A multicenter study

BACKGROUND

Ibrutinib has revolutionized the treatment of mantle cell lymphoma (MCL). Both ibrutinib monotherapy and ibrutinib-based combination therapy are important salvage options for patients with relapsed/refractory (R/R) MCL. The real-world efficacy and safety profile of the two strategies in Chinese patients with R/R MCL remain unclarified.

METHODS

In the present study, data of 121 R/R MCL patients who received either ibrutinib monotherapy (N = 68) or ibrutinib combination therapy (N = 53) in 13 medical centers in China were retrospectively reviewed.

RESULTS

With a median follow-up of 20.5 months, the overall response rate was 60.3% versus 84.9% (p = 0.003), complete remission rate was 16.2% versus 43.4% (p < 0.001), and median progression-free survival (PFS) was 18.5 months (95% confidence interval [CI], 12.1-21.8) vs. 30.8 months (95% CI, 23.5-NR) (hazard ratio, 0.53 [95% CI, 0.30-0.93]; p = 0.025), with ibrutinib monotherapy and ibrutinib-based combination therapy, respectively. Subgroup analysis showed that patients with male gender, no refractory disease, Ki67 <30%, previous line of therapy = 1, non-blastoid subtype, and the number of extranodal sites involved <2 might benefits more from the combination therapy. Treatment-emergent adverse events were similar, except for a higher incidence of all grade neutropenia in the ibrutinib combination group (12.7% vs. 32.0%, p = 0.017).

CONCLUSIONS

Ibrutinib combination therapy demonstrated potentially superior efficacy and comparable tolerability to ibrutinib monotherapy. Ibrutinib-based combination therapy could be one of the prominent treatment options for R/R MCL patients.

BTK inhibitors in the treatment of hematological malignancies and inflammatory diseases: mechanisms and clinical studies

Bruton's tyrosine kinase (BTK) is an essential component of multiple signaling pathways that regulate B cell and myeloid cell proliferation, survival, and functions, making it a promising therapeutic target for various B cell malignancies and inflammatory diseases. Five small molecule inhibitors have shown remarkable efficacy and have been approved to treat different types of hematological cancers, including ibrutinib, acalabrutinib, zanubrutinib, tirabrutinib, and orelabrutinib. The first-in-class agent, ibrutinib, has created a new era of chemotherapy-free treatment of B cell malignancies. Ibrutinib is so popular and became the fourth top-selling cancer drug worldwide in 2021. To reduce the off-target effects and overcome the acquired resistance of ibrutinib, significant efforts have been made in developing highly selective second- and third-generation BTK inhibitors and various combination approaches. Over the past few years, BTK inhibitors have also been repurposed for the treatment of inflammatory diseases. Promising data have been obtained from preclinical and early-phase clinical studies. In this review, we summarized current progress in applying BTK inhibitors in the treatment of hematological malignancies and inflammatory disorders, highlighting available results from clinical studies.

Tipping the balance: toward rational combination therapies to overcome venetoclax resistance in mantle cell lymphoma

Mantle cell lymphoma (MCL), an aggressive, but incurable B-cell lymphoma, is genetically characterized by the t(11;14) translocation, resulting in the overexpression of Cyclin D1. In addition, deregulation of the B-cell lymphoma-2 (BCL-2) family proteins BCL-2, B-cell lymphoma-extra large (BCL-XL), and myeloid cell leukemia-1 (MCL-1) is highly common in MCL. This renders these BCL-2 family members attractive targets for therapy; indeed, the BCL-2 inhibitor venetoclax (ABT-199), which already received FDA approval for the treatment of chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML), shows promising results in early clinical trials for MCL. However, a significant subset of patients show primary resistance or will develop resistance upon prolonged treatment. Here, we describe the underlying mechanisms of venetoclax resistance in MCL, such as upregulation of BCL-XL or MCL-1, and the recent (clinical) progress in the development of inhibitors for these BCL-2 family members, followed by the transcriptional and (post-)translational (dys)regulation of the BCL-2 family proteins, including the role of the lymphoid organ microenvironment. Based upon these insights, we discuss how rational combinations of venetoclax with other therapies can be exploited to prevent or overcome venetoclax resistance and improve MCL patient outcome.

Rare germline ATM variants of uncertain significance in chronic lymphocytic leukaemia and other cancers

Germline pathogenic ATM (ataxia-telangiectasia mutated) variants are associated with the risk of multiple cancers; however, genetic testing reveals a large number of ATM variants of uncertain significance (VUS). Here, we studied germline ATM variants occurring in a real-world cohort of 336 patients with chronic lymphocytic leukaemia (CLL) and public cancer whole-exome/genome-sequencing datasets (445 CLL, 75 mantle cell lymphoma, 216 metastatic breast cancer, 140 lung cancer patients). We found that two-thirds of rare germline ATM variants are pathogenic (18%-50%) or VUS-predicted pathogenic (50%-82%), depending on cancer type and reaching a prevalence of up to 8%, and one-third are VUS-predicted benign. Patients with both pathogenic and VUS-predicted pathogenic variants, all heterozygous, mostly missense, are more predisposed to biallelic ATM inactivation by acquiring deletion (del)11q than patients without these variants, similar to patients with somatic ATM variants. A functional assay of ATM activity in primary CLL cells proved that VUS-predicted pathogenic ATM variants partially reduce ATM activity and concurrent del(11q) leads to complete loss of ATM activity. The rare germline variants were associated with reduced progression-free survival in CLL on novel agents, comparable to somatic ATM or TP53 disruptions. Our results highlight the need to determine the pathogenicity of VUS in clinically relevant genes such as ATM.

Factors associated with bone marrow involvement in lymphoma staging bone marrow examination: A South African single-centre retrospective study

Background: Accurate detection of bone marrow involvement (BMI) in lymphoma is important as it signifies stage 4 disease. Staging bone marrow examination (BME), therefore, influences treatment decisions and prognostication. The prevalence of BMI depends on multiple factors at presentation including lymphoma subtype, age, sex, human immunodeficiency virus (HIV) status and haematological parameters.Aim: To determine risk factors for BMI in lymphoma staging.Setting: The study was conducted in the department of haematological pathology, Tygerberg Hospital, Cape Town, South Africa.Methods: Retrospective cross-sectional descriptive study in adult patients, reviewing BMI and associated parameters, during their initial lymphoma staging procedure between 2016 and 2019.Results: Of a total of 387 lymphoma staging cases that were evaluated, 30.0% of them showed BMI. Diffuse large B-cell lymphoma, Hodgkin lymphoma and high-grade B-cell lymphoma were the most frequent subtypes diagnosed. The highest prevalence of BMI was in low-grade lymphomas. There was a statistically significant association between BMI and advanced age, pancytopenia and bicytopenia (anaemia with leucopenia, anaemia with thrombocytopenia or leucopenia with thrombocytopenia). Bicytopenia and pancytopenia showed high positive predictive values of BMI, respectively, 61.0% and 69.0%. Human immunodeficiency virus positivity (34.6%) was not predictive of BMI across all lymphoma subtypes. Normal blood counts had a high negative predictive value for BMI.Conclusion: BME remains an important part of lymphoma staging with 30.0% of all lymphomas showing BMI.

Dihydroorotate dehydrogenase inhibition acts synergistically with tyrosine kinase inhibitors to induce apoptosis of mantle cell lymphoma cells

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma that remains incurable with the treatment options available today. In the present study, we have identified the dihydroorotate dehydrogenase (DHODH), an essential enzyme for the de novo biosynthesis of pyrimidine-based nucleotides, to be overexpressed in MCL in comparison to healthy peripheral blood mononuclear cells (PBMC). In vitro inhibition of the DHODH activity using a newly developed DHODH inhibitor, namely (R)-HZ05, can induce MCL cell death in the nanomolar range independently than the P53 status of the investigated cell lines. Moreover, the combination of (R)-HZ05 with tyrosine kinase inhibitor shows the synergistic activity on cell death. Pre-clinical investigation on the efficacy of (R)-HZ05 shows that it can be prolonged animal lifespan similar to ibrutinib. (R)-HZ05 use in combination with tyrosine kinase inhibitor demonstrated a superior efficacy on tumor burden reduction and survival than either drug alone. We have demonstrated that the depletion of the pyrimidine nucleotide pool, using DHODH inhibitor, represents a new therapeutic strategy that may benefit MCL patients.

Emerging role of exosomes in hematological malignancies

Hematological malignancies are a heterogeneous group of neoplasms in the blood characterized by dysregulated hematopoiesis and classified as leukemia, lymphoma, and myeloma. The occurrence and progression of hematological malignancies depend on transformed hematopoietic stem cells, which refract to chemotherapy and often cause relapse. In recent years, monoclonal antibody therapies are preferred for hematopoietic cancers, owing to their inherent mechanisms of action and improved outcomes. However, efficient drug delivery methods and the establishment of novel biomarkers are currently being investigated and warranted to improve the outcome of patients with hematological malignancies. For instance, non-viral-mediated, natural carriers have been suggested for latent intracellular drug delivery. In this purview, repurposing small vesicles (e.g., exosomes) is considered a latent approach for myeloma therapy. Exosomes (nano-vesicles) have many advantages in that they are secreted by various animals and plants and become sought after for therapeutic and diagnostic purposes. The size of the cellular membrane of exosomes (30-150 nm) facilitates ligand binding and targeted delivery of the loaded molecules. Furthermore, exosomes can be modified to express specific target moiety on their cell membrane and can also be featured with desired biological activity, thereby potentially employed for various convoluted diseases, including hematological malignancies. To advance the current knowledge, this review is focused on the source, composition, function and surface engineering of exosomes pertaining to hematological malignancies.

Tumor Microenvironment and Immunotherapy-Based Approaches in Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma (NHL) characterized by the translocation t(11;14) (q13;q32) and a poor response to rituximab–anthracycline-based chemotherapy. High-dose cytarabine-based regimens offer a durable response, but an important number of MCL patients are not eligible for intensive treatment and are ideal candidates for novel targeted therapies (such as BTK, proteasome or BCL2 inhibitors, Immunomodulatory Drugs (IMiDs), bispecific antibodies, or CAR-T cell therapy). On the bench side, several studies aiming to integrate the tumor within its ecosystem highlighted a critical role of the tumor microenvironment (TME) in the expansion and resistance of MCL. This led to important insights into the role of the TME in the management of MCL, including potential targets and biomarkers. Indeed, targeted agents often have a combined mechanism of action on the tumor B cell but also on the tumor microenvironment. The aim of this review is to briefly describe the current knowledge on the biology of the TME in MCL and expose the results of the different therapeutic strategies integrating the TME in this disease.

Evaluation of Proteasome Inhibitors in the Treatment of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common form of idiopathic interstitial pneumonia, and it has a worse prognosis than non-small cell lung cancer. The pathomechanism of IPF is not fully understood, but it has been suggested that repeated microinjuries of epithelial cells induce a wound healing response, during which fibroblasts differentiate into myofibroblasts. These activated myofibroblasts express α smooth muscle actin and release extracellular matrix to promote matrix deposition and tissue remodeling. Under physiological conditions, the remodeling process stops once wound healing is complete. However, in the lungs of IPF patients, myofibroblasts re-main active and deposit excess extracellular matrix. This leads to the destruction of alveolar tissue, the loss of lung elastic recoil, and a rapid decrease in lung function. Some evidence has indicated that proteasomal inhibition combats fibrosis by inhibiting the expressions of extracellular matrix proteins and metalloproteinases. However, the mechanisms by which proteasome inhibitors may protect against fibrosis are not known. This review summarizes the current research on proteasome inhibitors for pulmonary fibrosis, and provides a reference for whether proteasome inhibitors have the potential to become new drugs for the treatment of pulmonary fibrosis.

CAR T-Cell Therapy in the Older Person: Indications and Risks

PURPOSE OF REVIEW

Validated metrics to optimize older adult patient selection for Chimeric Antigen Receptor T-cell therapy (CART) are lacking; however, some preliminary data suggests that geriatric assessments and cumulative illness rating score may be useful tools. In addition, interventions capable of enhancing outcomes in older adults receiving CART have yet to be elucidated. The purpose of this review is to present data extrapolating from other diseases and therapeutic modalities, related to product selection, toxicity mitigation strategies, comprehensive coordinated models of care, and functional optimization of patients.

RECENT FINDINGS

The most robust data in older adults are among relapsed and refractory (r/r) diffuse large B-cell lymphoma (DLBCL) patients where three products are available with the longest clinical follow up and the most abundant real-world evidence (RWE). Data for the approved CART products for follicular lymphoma (FL) and mantle cell lymphoma (MCL) are relatively new and RWE is lacking in general. Data for CART products in multiple myeloma (MM) and B-cell acute lymphoblastic leukemia (B-ALL) are even more recent, but preliminary data in older adults seem to follow the trend of excellent efficacy in this age group with age-stratified toxicity data limited. Landmark trials and RWE studies indicate that the high response rates of CART for older adult patients, age 65 years and older, are maintained, while toxicity may be amplified. Clinically important toxicities include grade 3 or higher cytokine release syndrome (CRS), neurotoxicity, and infections.

Clinical and biological features of mantle cell lymphoma patients with co-expression of CD10 and BCL-6: a retrospective study

Background

Mantle cell lymphoma (MCL) with co-expression of CD10 and BCL-6 was scarcely reported, and its biological features were largely remained unknown. Thus, this study aimed to describe the clinical and biological features, as well as outcome of MCL patients with co-expression of CD10 and BCL-6.

Methods

A total of 104 cases of MCL who were admitted to our hospital between January 2011 and October 2018 were recruited. Those patients were diagnosed according to the 2016 World Health Organization (WHO) classification system for tumors of the hematopoietic and lymphoid tissues, in compliance with the results of cytomorphology and immunohistochemical analysis. Patients were followed up through telephone interviews, medical records. Differences in age, gender, leukocyte count, lactate dehydrogenase (LDH) level, beta-2 microglobulin (β2-MG) level and results of immunohistochemistry were analyzed. Then the event-free survival (EFS) rate and overall survival (OS) rate were performed by the Kaplan-Meier method and log-rank test.

Results

The results showed that, in total, 5 patients had superficial lymph node enlargement, 2 patients suffered from abdominal discomfort, and 1 patient’s red blood cell (RBC) count was abnormal at the time of diagnosis. All patients were in stage IV, 75% had bone marrow involvement, and 75% and 100% of patients had elevated levels of LDH and β2-MG, respectively. Three classic genes and five variants were involved in the 8 patients. MCL patients with the co-expression of CD10 and BCL-6 had higher Ki-67 index, white blood cell (WBC) count, LDH level, and β2-MG level than those of without co-expression of CD10 and BCL-6 (P=0.025, 0.038, 0.015, and 0.021, respectively). Besides, MCL patients with CD10 and BCL-6 co-expression had shorter OS and EFS (χ²=6.401 and 5.975; P=0.011 and 0.015, respectively), indicating patients’ susceptibility to get complex karyotype and TP53 abnormality.

Conclusions

MCL patients with co-expression of CD10 and BCL-6 were more likely to have bone marrow involvement, higher Ki-67 index, increased WBC count, and elevated levels of LDH and β2-MG at the time of diagnosis, then might has complex cytogenetic and poor prognosis.

Clinical characteristics and outcomes of ocular adnexal mantle cell lymphoma

PURPOSE

To compare characteristics of initial ocular adnexal (OA) mantle cell lymphoma (MCL) and initial systemic MCL.

METHODS

Retrospective, comparative case series. Patients treated for MCL at Mayo Clinic from 1/1/1990 to 11/30/2020. MCL was classified as initial OA if first site was OA or initial systemic if first site was elsewhere with progression or recurrence to the OA region.

OUTCOME MEASURES

Features, treatment, and survival.

RESULTS

There were 50 patients with MCL, 23 initial OA and 27 initial systemic. Patients with initial OA MCL had more conjunctival (52% vs. 19%, p = .017) involvement and less frequently received chemotherapy plus autologous stem cell transplant (ASCT) (9% vs. 33%, p = .046) as initial treatment. Complete remission was achieved in 41 (91% vs. 74%, p = .152) patients. Five-year disease-specific survival was similar in initial OA and initial systemic MCL (92% vs. 83%, p = .187). Subanalysis of patients with initial OA MCL revealed 9 (39%) patients developed tumor recurrence, with mean time to recurrence of 28 months. Comparison (no recurrence vs. recurrence) of initial OA MCL patients revealed those with no recurrence had shorter mean final follow-up (3.3 vs. 9.8 years, p = .005) and more frequent initial treatment with rituximab-based chemotherapy plus ASCT (43% vs. 0%, p = .048). Recurrence had no effect on the 5-year age-adjusted risk of death from lymphoma (HR 2.17, 95% CI 0.55-9.09, p = .266).

CONCLUSIONS

Initial OA and initial systemic MCL patients differ in presentation and management but have similar survival.

Genomic and transcriptomic profiling reveals distinct molecular subsets associated with outcomes in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a phenotypically and genetically heterogeneous malignancy in which the genetic alterations determining clinical indications are not fully understood. Here, we performed a comprehensive whole-exome sequencing analysis of 152 primary samples derived from 134 MCL patients, including longitudinal samples from 16 patients and matched RNA-Seq data from 48 samples. We classified MCL into 4 robust clusters (C1-C4). C1 featured mutated immunoglobulin heavy variable (IGHV), CCND1 mutation, amp(11q13), and active B cell receptor (BCR) signaling. C2 was enriched with del(11q)/ATM mutations and upregulation of NF-κB and DNA repair pathways. C3 was characterized by mutations in SP140, NOTCH1, and NSD2, with downregulation of BCR signaling and MYC targets. C4 harbored del(17p)/TP53 mutations, del(13q), and del(9p), and active MYC pathway and hyperproliferation signatures. Patients in these 4 clusters had distinct outcomes (5-year overall survival [OS] rates for C1-C4 were 100%, 56.7%, 48.7%, and 14.2%, respectively). We also inferred the temporal order of genetic events and studied clonal evolution of 16 patients before treatment and at progression/relapse. Eleven of these samples showed drastic clonal evolution that was associated with inferior survival, while the other samples showed modest or no evolution. Our study thus identifies genetic subsets that clinically define this malignancy and delineates clonal evolution patterns and their impact on clinical outcomes.

P300/CBP inhibition sensitizes mantle cell lymphoma to PI3Kδ inhibitor idelalisib

Mantle cell lymphoma (MCL) is a lymphoproliferative disorder lacking reliable therapies. PI3K pathway contributes to the pathogenesis of MCL, serving as a potential target. However, idelalisib, an FDA-approved drug targeting PI3Kδ, has shown intrinsic resistance in MCL treatment. Here we report that a p300/CBP inhibitor, A-485, could overcome resistance to idelalisib in MCL cells in vitro and in vivo. A-485 was discovered in a combinational drug screening from an epigenetic compound library containing 45 small molecule modulators. We found that A-485, the highly selective catalytic inhibitor of p300 and CBP, was the most potent compound that enhanced the sensitivity of MCL cell line Z-138 to idelalisib. Combination of A-485 and idelalisib remarkably decreased the viability of three MCL cell lines tested. Co-treatment with A-485 and idelalisib in Maver-1 and Z-138 MCL cell xenograft mice for 3 weeks dramatically suppressed the tumor growth by reversing the unsustained inhibition in PI3K downstream signaling. We further demonstrated that p300/CBP inhibition decreased histone acetylation at RTKs gene promoters and reduced transcriptional upregulation of RTKs, thereby inhibiting the downstream persistent activation of MAPK/ERK signaling, which also contributed to the pathogenesis of MCL. Therefore, additional inhibition of p300/CBP blocked MAPK/ERK signaling, which rendered maintaining activation to PI3K-mTOR downstream signals p-S6 and p-4E-BP1, thus leading to suppression of cell growth and tumor progression and eliminating the intrinsic resistance to idelalisib ultimately. Our results provide a promising combination therapy for MCL and highlight the potential use of epigenetic inhibitors targeting p300/CBP to reverse drug resistance in tumor.

KRAS and RAS-MAPK Pathway Deregulation in Mature B Cell Lymphoproliferative Disorders

KRAS mutations account for the most frequent mutations in human cancers, and are generally correlated with disease aggressiveness, poor prognosis, and poor response to therapies. KRAS is required for adult hematopoiesis and plays a key role in B cell development and mature B cell proliferation and survival, proved to be critical for B cell receptor-induced ERK pathway activation. In mature B cell neoplasms, commonly seen in adults, KRAS and RAS-MAPK pathway aberrations occur in a relevant fraction of patients, reaching high recurrence in some specific subtypes like multiple myeloma and hairy cell leukemia. As inhibitors targeting the RAS-MAPK pathway are being developed and improved, it is of outmost importance to precisely identify all subgroups of patients that could potentially benefit from their use. Herein, we review the role of KRAS and RAS-MAPK signaling in malignant hematopoiesis, focusing on mature B cell lymphoproliferative disorders. We discuss KRAS and RAS-MAPK pathway aberrations describing type, incidence, mutual exclusion with other genetic abnormalities, and association with prognosis. We review the current therapeutic strategies applied in mature B cell neoplasms to counteract RAS-MAPK signaling in pre-clinical and clinical studies, including most promising combination therapies. We finally present an overview of genetically engineered mouse models bearing KRAS and RAS-MAPK pathway aberrations in the hematopoietic compartment, which are valuable tools in the understanding of cancer biology and etiology.

Ibrutinib in Combination With Rituximab for Indolent Clinical Forms of Mantle Cell Lymphoma (IMCL-2015): A Multicenter, Open-Label, Single-Arm, Phase II Trial

The need for an individualized management of indolent clinical forms in mantle cell lymphoma (MCL) is increasingly recognized. We hypothesized that a tailored treatment with ibrutinib in combination with rituximab (IR) could obtain significant responses in these patients.

Outcomes for Recurrent Mantle Cell Lymphoma Post-Ibrutinib Therapy: A Retrospective Cohort Study from a Japanese Administrative Database

INTRODUCTION

Treatment options in patients with mantle cell lymphoma (MCL) failing ibrutinib are limited, with no standard therapies defined. This study aimed to investigate real-world treatment patterns and outcomes for patients with MCL following ibrutinib.

METHODS

This study utilized a de-identified hospital-based claims database (Medical Data Vision) in Japan. Eligible patients were adults who were diagnosed with MCL and had received antitumor drugs between December 2010 and July 2020. Patients were followed from the first antitumor drug treatment until the end of available data up to July 2021. Time-to-event analyses utilized the Kaplan-Meier method. Factors for receiving post-ibrutinib therapy were explored with logistic regression analysis.

RESULTS

Of the 1386 patients who started antitumor drug therapy, 247 patients received and discontinued ibrutinib at any line of therapy. Among them, 137 patients (55.5%) received subsequent therapy. The median age at the end of ibrutinib therapy was 77 (range 42-95), and 44 patients had a dependent activity of daily living (ADL). Factors negatively associated with receiving post-ibrutinib therapy after discontinuation of ibrutinib were age ≥ 75 years (odds ratio [95% CI] 0.46 [0.26-0.80]) and emergency hospital admissions (0.37 [0.17-0.84]). Immediate post-ibrutinib therapy regimens were highly diverse, with BR (bendamustine, rituximab) only prescribed in more than 10% of patients. The median duration of post-ibrutinib therapy was 1.5 months (95% CI 1.07-2.07). The median overall survival from the end of ibrutinib therapy in patients regardless of the receipt of post-ibrutinib therapy (n = 247), in those who did not receive post-ibrutinib therapy (n = 110), and in those who received post-ibrutinib therapy (n = 137) was 5.6 months (95% CI 3.8-8.7), 2.3 months (95% CI 1.2-3.9), and 8.7 months (95% CI 5.6-13.8), respectively. The most common adverse event during post-ibrutinib therapy was infection, with the use of anti-infectives (17%).

CONCLUSIONS

Patients with MCL previously treated with ibrutinib have poor ability to carry out ADL and experience very poor outcomes. New safe, effective therapies are needed.

Current Knowledge in Genetics, Molecular Diagnostic Tools, and Treatments for Mantle Cell Lymphomas

Mantle Cell lymphoma (MCL) is a mature B-cell lymphoma with a well-known hallmark genetic alteration in most cases, t (11,14)(q13q32)/CCND1-IGH. However, our understanding of the genetic and epigenetic alterations in MCL has evolved over the years, and it is now known that translocations involving CCND2, or cryptic insertion of enhancer elements of IGK or IGL gene, can also lead to MCL. On a molecular level, MCL can be broadly classified into two subtypes, conventional MCL (cMCL) and non-nodal MCL (nnMCL), each with different postulated tumor cell origin, clinical presentation and behavior, mutational pattern as well as genomic complexity. This article reviews both the common and rare alterations in MCL on a gene mutational, chromosomal arm, and epigenetic level, in the context of their contribution to the lymphomagenesis and disease evolution in MCL. This article also summarizes the important prognostic factors, molecular diagnostic tools, and treatment options based on the most recent MCL literature.

Rare t(X;14)(q28;q32) translocation reveals link between MTCP1 and chronic lymphocytic leukemia

Rare, recurrent balanced translocations occur in a variety of cancers but are often not functionally interrogated. Balanced translocations with the immunoglobulin heavy chain locus (IGH; 14q32) in chronic lymphocytic leukemia (CLL) are infrequent but have led to the discovery of pathogenic genes including CCND1, BCL2, and BCL3. Following identification of a t(X;14)(q28;q32) translocation that placed the mature T cell proliferation 1 gene (MTCP1) adjacent to the immunoglobulin locus in a CLL patient, we hypothesized that this gene may have previously unrecognized importance. Indeed, here we report overexpression of human MTCP1 restricted to the B cell compartment in mice produces a clonal CD5⁺/CD19⁺ leukemia recapitulating the major characteristics of human CLL and demonstrates favorable response to therapeutic intervention with ibrutinib. We reinforce the importance of genetic interrogation of rare, recurrent balanced translocations to identify cancer driving genes via the story of MTCP1 as a contributor to CLL pathogenesis.

Cyclin D2 overexpression drives B1a-derived MCL-like lymphoma in mice

Mantle cell lymphoma (MCL) is an aggressive B cell lymphoma with poor long-term overall survival. Currently, MCL research and development of potential cures is hampered by the lack of good in vivo models. MCL is characterized by recurrent translocations of CCND1 or CCND2, resulting in overexpression of the cell cycle regulators cyclin D1 or D2, respectively. Here, we show, for the first time, that hematopoiesis-specific activation of cyclin D2 is sufficient to drive murine MCL-like lymphoma development. Furthermore, we demonstrate that cyclin D2 overexpression can synergize with loss of p53 to form aggressive and transplantable MCL-like lymphomas. Strikingly, cyclin D2-driven lymphomas display transcriptional, immunophenotypic, and functional similarities with B1a B cells. These MCL-like lymphomas have B1a-specific B cell receptors (BCRs), show elevated BCR and NF-κB pathway activation, and display increased MALT1 protease activity. Finally, we provide preclinical evidence that inhibition of MALT1 protease activity, which is essential for the development of early life-derived B1a cells, can be an effective therapeutic strategy to treat MCL.

Detailed characterization of the transcriptome of single B cells in mantle cell lymphoma suggesting a potential use for SOX4

Mantle cell lymphoma (MCL) is a malignancy arising from naive B lymphocytes with common bone marrow (BM) involvement. Although t(11;14) is a primary event in MCL development, the highly diverse molecular etiology and causal genomic events are still being explored. We investigated the transcriptome of CD19⁺ BM cells from eight MCL patients at single-cell level. The transcriptomes revealed marked heterogeneity across patients, while general homogeneity and clonal continuity was observed within the patients with no clear evidence of subclonal involvement. All patients were SOX11⁺CCND1⁺CD20⁺. Despite monotypic surface immunoglobulin (Ig) κ or λ protein expression in MCL, 10.9% of the SOX11 + malignant cells expressed both light chain transcripts. The early lymphocyte transcription factor SOX4 was expressed in a fraction of SOX11 + cells in two patients and co-expressed with the precursor lymphoblastic marker, FAT1, in a blastoid case, suggesting a potential prognostic role. Additionally, SOX4 was found to identify non-malignant SOX11^– pro-/pre-B cell populations. Altogether, the observed expression of markers such as SOX4, CD27, IgA and IgG in the SOX11⁺ MCL cells, may suggest that the malignant cells are not fixed in the differentiation state of naïve mature B cells, but instead the patients carry B lymphocytes of different differentiation stages.

Bortezomib enhances the anti-cancer effect of the novel Bruton's tyrosine kinase inhibitor (BGB-3111) in mantle cell lymphoma expressing BTK

BGB-3111, a novel Bruton's tyrosine kinase (BTK) inhibitor, shows promising anti-cancer effects in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), mantle cell lymphoma (MCL), and Waldenstrom macroglobulinemia (WM). This study aimed to investigate the anti-cancer effects of BGB-3111 combined with bortezomib (BTZ) against the BTK-expressing MCL. We found that BTK, which was overexpressed in 59.4% of patients with MCL, was mainly characterized by high Ki67 and elevated MIPI scores. BGB-3111 strongly inhibited cell proliferation, induced cell cycle arrest in the G1/G0-phase, and promoted cell apoptosis in the MCL cells expressing BTK. BGB-3111 provides better safety than another BTK inhibitor, ibrutinib as ibrutinib inhibits the inducible T-cell kinase (ITK) as an off-target effect but BGB-3111 does not inhibit ITK. Low doses of BTZ enhanced the anti-cancer effect induced by the low dose of BGB-3111 by downregulating the expression levels of PARP and Bcl-2 and increasing the expression levels of cleaved PARP and cleaved caspase-9. In addition, low doses of BGB-3111, but not of BTZ, inhibited BTK phosphorylation. However, low-doses of BTZ strengthened the anti-cancer effect induced by the low-doses of BGB-3111 via synergistically suppressing the IκBα and P65 phosphorylation. Taken together, our findings validate that BGB-3111 is a novel and effective BTK inhibitor for MCL-expressing BTK. Hence, it can be harnessed as a potential therapeutic strategy through a combinatorial treatment comprising low-dose BGB-3111 and low-dose BTZ to gain strong anti-cancer effects and better safety for MCL patients.

A Rare Case of Severe Lactic Acidosis in a Patient With Mantle Cell Lymphoma

Lactic acidosis is an extremely rare paraneoplastic manifestation of hematological malignancies, and often carries an extremely poor prognosis. Mantle cell lymphoma is an aggressive and rare form of non-Hodgkin lymphoma. To the best of our knowledge, it is extremely rare to have severe lactic acidosis in patients with mantle cell lymphoma. In this article, we are reporting a rare case of mantle cell lymphoma diagnosed with typical cluster differentiation (CD markers) in bone marrow examination with persistent lactic acidosis refractory to intravenous hydration that responded well to chemotherapy. Malignant lactic acidosis is a medical emergency that needs rapid evaluation and identification that shows improved prognosis after the introduction of chemotherapy.

Advances in Classification and Treatment of Non-Hodgkin Lymphoma: Mantle Cell

Mantle cell lymphoma is a rare, aggressive, and largely incurable form of non-Hodgkin lymphoma. There are a number of well-characterized prognostic features but nothing that can help guide therapy. Treatment with chemotherapy is generally effective in the short term, but relapse is inevitable and subsequent treatment is challenging. The use of Bruton tyrosine kinase inhibitors, however, has transformed practice. These agents are highly active in relapsed disease and are very well-tolerated drugs. Chemotherapy-free combinations using Bruton tyrosine kinase inhibitors look very exciting and will likely evolve to be part of frontline care in the future.

Leukemic Variant of Mantle Cell Lymphoma: Clinical Presentation and Management

PURPOSE OF REVIEW

This review summarizes the unique presentation and management of the leukemic variant of mantle cell lymphoma (LV-MCL, also referred to as non-nodal MCL) and highlights the biologic and clinical differentiation from classical mantle cell lymphoma (cMCL) in biomarker expression, clinical features, prognosis, disease course, and treatment.

RECENT FINDINGS

Several studies have evaluated the gene expression profile of mantle cell lymphoma, differentiating LV-MCL from cMCL. The typical immunophenotypic profile is CD5-positive, SOX 11-negative, CD23-low, CD200-low, and cyclin D1 overexpressed. LV-MCL commonly has mutated immunoglobulin heavy chain variable region genes. Data on treatment of LV-MCL is limited to retrospective analyses; the ideal treatment for these patients is unknown although many have a clinically indolent, asymptomatic presentation and often may be observed for an extended period without active treatment. LV-MCL is a clinically and biologically distinct entity. Clinically, it must be distinguished from chronic lymphocytic leukemia and cMCL. Future prospective, randomized clinical trials are required to optimize management, define the initial treatment, and appropriately sequence treatment modalities.

Progress in molecular feature of smoldering mantle cell lymphoma

Mantle cell lymphoma (MCL) is considered one of the most aggressive lymphoid tumors. However, it sometimes displays indolent behavior in patients and might not necessitate treatment at diagnosis; this has been described as "smoldering MCL" (SMCL). There are significant differences in the diagnosis, prognosis, molecular mechanisms and treatments of indolent MCL and classical MCL. In this review, we discuss the progress in understanding the molecular mechanism of indolent MCL to provide insights into the genomic nature of this entity. Reported findings of molecular features of indolent MCL include a low Ki-67 index, CD200 positivity, a low frequency of mutations in TP53, a lack of SOX11, normal arrangement and expression of MYC, IGHV mutations, differences from classical MCL by L-MCL16 assays and MCL35 assays, an unmutated P16 status, few defects in ATM, no NOTCH1/2 mutation, Amp 11q gene mutation, no chr9 deletion, microRNA upregulation/downregulation, and low expression of several genes that have been valued in recent years (SPEN, SMARCA4, RANBP2, KMT2C, NSD2, CARD11, FBXW7, BIRC3, KMT2D, CELSR3, TRAF2, MAP3K14, HNRNPH1, Del 9p and/or Del 9q, SP140 and PCDH10). Based on the above molecular characteristics, we may distinguish indolent MCL from classical MCL. If so, indolent MCL will not be overtreated, whereas the treatment of classical MCL will not be delayed.

Mantle cell lymphoma-Advances in molecular biology, prognostication and treatment approaches

Mantle cell lymphoma (MCL) is clinically characterized by its heterogenous behavior with courses ranging from indolent cases that do not require therapy for years to highly aggressive MCL with very limited prognosis. A better understanding of the complex biology of MCL has already led to the approval of several innovative agents, expanding the landscape of MCL therapies and improving therapeutic options especially for refractory or relapsed disease. Nevertheless, to further optimize MCL treatment, early identification of individual risk profile and risk-adapted, patient-tailored choice of therapeutic strategy needs to be prospectively incorporated in clinical patient management. This review highlights recent advances in deciphering the molecular background of MCL, the definition of prognostically relevant factors and the identification of potential druggable targets and summarizes current treatment recommendations for primary and relapsed/refractory MCL including novel targeted therapies.