Pleiotropic Action of Novel Bruton's Tyrosine Kinase Inhibitor BGB-3111 in Mantle Cell Lymphoma

Zanubrutinib delays selinexor resistance evolution in biopsy sample-derived primary central nervous system lymphoma models

Primary central nervous system lymphoma (PCNSL) is a rare and aggressive lymphoma of the brain with poor prognosis. The scarcity of cell lines established using PCNSL makes it difficult to conduct preclinical studies on new drugs. We aimed to explore the effect of selinexor combined with zanubrutinib in PCNSL using established PCNSL cells and an orthotopic PCNSL model. Primary PCNSL cells were successfully cultured. Selinexor inhibited proliferation, induced G1 phase arrest, and promoted apoptosis, however, induced drug resistance in PCNSL. Selinexor combined with zanubrutinib had a synergistic effect on PCNSL and prevented the onset of selinexor resistance in PCNSL by inhibiting AKT signaling. Moreover, selinexor combined with zanubrutinib notably slowed tumor growth and prolonged survival compared to that of the control. Overall, the addition of zanubrutinib to selinexor monotreatment had a synergistic effect in vitro and prolonged survival in vivo.

Potentiation of apoptosis in drug-resistant mantle cell lymphoma cells by MCL-1 inhibitor involves downregulation of inhibitor of apoptosis proteins

Bruton's tyrosine kinase inhibitors (BTKi) and CAR T-cell therapy have demonstrated tremendous clinical benefits in mantle cell lymphoma (MCL) patients, but intrinsic or acquired resistance inevitably develops. In this study, we assessed the efficacy of the highly potent and selective MCL-1 inhibitor AZD5991 in various therapy-resistant MCL cell models. AZD5991 markedly induced apoptosis in these cells. In addition to liberating BAK from the antiapoptotic MCL-1/BAK complex for the subsequent apoptosis cascade, AZD5991 downregulated inhibitor of apoptosis proteins (IAPs) through a BAK-dependent mechanism to amplify the apoptotic signal. The combination of AZD5991 with venetoclax enhanced apoptosis and reduced mitochondrial oxygen consumption capacity in MCL cell lines irrespective of their BTKi or venetoclax sensitivity. This combination also dramatically inhibited tumor growth and prolonged mouse survival in two aggressive MCL patient-derived xenograft models. Mechanistically, the augmented cell lethality was accompanied by the synergistic suppression of IAPs. Supporting this notion, the IAP antagonist BV6 induced dramatic apoptosis in resistant MCL cells and sensitized the resistant MCL cells to venetoclax. Our study uncovered another unique route for MCL-1 inhibitor to trigger apoptosis, implying that the pro-apoptotic combination of IAP antagonists and apoptosis inducers could be further exploited for MCL patients with multiple therapeutic resistance.

Targeting glutaminase is therapeutically effective in ibrutinib-resistant mantle cell lymphoma

Mantle cell lymphoma (MCL) is an incurable B-cell non-Hodgkin lymphoma characterized by frequent relapses. The development of resistance to ibrutinib therapy remains a major challenge in MCL. We previously showed that glutaminolysis is associated with resistance to ibrutinib. In this study, we confirmed that glutaminase (GLS), the first enzyme in glutaminolysis, is overexpressed in ibrutinib-resistant MCL cells, and that its expression correlates well with elevated glutamine dependency and glutaminolysis. Furthermore, we discovered that GLS expression correlates with MYC expression and the functioning of the glutamine transporter ASCT2. Depletion of glutamine or GLS significantly reduced cell growth, while GLS overexpression enhanced glutamine dependency and ibrutinib resistance. Consistent with this, GLS inhibition by its specific inhibitor telaglenastat suppressed MCL cell growth both in vitro and in vivo. Moreover, telaglenastat showed anti-MCL synergy when combined with ibrutinib or venetoclax in vitro, which was confirmed using an MCL patient-derived xenograft model. Our study provides the first evidence that targeting GLS with telaglenastat, alone or in combination with ibrutinib or venetoclax, is a promising strategy to overcome ibrutinib resistance in MCL.

Synergistic disruption of BTK and BCL-2 causes apoptosis while inducing ferroptosis in double-hit lymphoma

Double-hit lymphoma (DHL) is an aggressive subset of Diffuse Large B-cell Lymphoma (DLBCL) with poor outcomes and without satisfying treatment options. BTK inhibitor monotherapy is ineffective to suppress aggressive lymphoma. Hence, combination with other potential agents is warranted. Here, we demonstrated the second generation of BTK inhibitor, zanubrutinib, and a BCL-2 inhibitor, navitoclax, worked in synergistic manner to suppress DHL. Comprehensive in silico approach by interrogating single-cell to bulk-level profiling was employed along with in vitro and in vivo validation in DHL cell lines. Ablation of BTK enhanced sensitivity to navitoclax and suppressed proliferation of DHL cells. Combination of second generation of BTK inhibitor with navitoclax synergistically suppressed DLBCL cells with higher synergy score in DHL subset. The drug combination triggered apoptosis and ferroptosis, with the latter being characterized by reactive oxygen species (ROS) accumulation, extensive lipid peroxidation, and depletion of reduced glutathione. Moreover, ablation of BTK sensitized DHL cells to ferroptosis. Mechanistically, disruption of BTK and BCL-2 triggered ferroptosis by downregulating NRF2 and HMOX1, while deactivating GPX4. Combination of zanubrutinib and navitoclax effectively suppressed tumor growth in vivo. Our data suggest that zanubrutinib and navitoclax synergistically suppressed DHL by inducing apoptosis and ferroptosis.

Exploiting PRMT5 as a target for combination therapy in mantle cell lymphoma characterized by frequent ATM and TP53 mutations

Constant challenges for the treatment of mantle cell lymphoma (MCL) remain to be recurrent relapses and therapy resistance, especially in patients harboring somatic mutations in the tumor suppressors ATM and TP53, which are accumulated as therapy resistance emerges and the disease progresses, consistent with our OncoPrint results that ATM and TP53 alterations were most frequent in relapsed/refractory (R/R) MCL. We demonstrated that protein arginine methyltransferase-5 (PRMT5) was upregulated in R/R MCL, which predicted a poor prognosis. PRMT5 inhibitors displayed profound antitumor effects in the mouse models of MCL with mutated ATM and/or TP53, or refractory to CD19-targeted CAR T-cell therapy. Genetic knockout of PRMT5 robustly inhibited tumor growth in vivo. Co-targeting PRMT5, and ATR or CDK4 by using their inhibitors showed synergistic antitumor effects both in vitro and in vivo. Our results have provided a rational combination therapeutic strategy targeting multiple PRMT5-coordinated tumor-promoting processes for the treatment of R/R MCL with high mutation burdens.

Cotargeting of BTK and MALT1 overcomes resistance to BTK inhibitors in mantle cell lymphoma

Bruton's tyrosine kinase (BTK) is a proven target in mantle cell lymphoma (MCL), an aggressive subtype of non-Hodgkin lymphoma. However, resistance to BTK inhibitors is a major clinical challenge. We here report that MALT1 is one of the top overexpressed genes in ibrutinib-resistant MCL cells, while expression of CARD11, which is upstream of MALT1, is decreased. MALT1 genetic knockout or inhibition produced dramatic defects in MCL cell growth regardless of ibrutinib sensitivity. Conversely, CARD11-knockout cells showed antitumor effects only in ibrutinib-sensitive cells, suggesting that MALT1 overexpression could drive ibrutinib resistance via bypassing BTK/CARD11 signaling. Additionally, BTK knockdown and MALT1 knockout markedly impaired MCL tumor migration and dissemination, and MALT1 pharmacological inhibition decreased MCL cell viability, adhesion, and migration by suppressing NF-κB, PI3K/AKT/mTOR, and integrin signaling. Importantly, cotargeting MALT1 with safimaltib and BTK with pirtobrutinib induced potent anti-MCL activity in ibrutinib-resistant MCL cell lines and patient-derived xenografts. Therefore, we conclude that MALT1 overexpression associates with resistance to BTK inhibitors in MCL, targeting abnormal MALT1 activity could be a promising therapeutic strategy to overcome BTK inhibitor resistance, and cotargeting of MALT1 and BTK should improve MCL treatment efficacy and durability as well as patient outcomes.

Synergistic Effects of Zanubrutinib Combined With CD19 CAR-T Cells in Raji Cells in Vitro and in Vivo

Background and Objects: Bruton's tyrosine kinase inhibitors are commonly used and effective for lymphoma and chronic lymphocytic leukemia (CLL). Ibrutinib might improve the effect of anti-cluster of differentiation 19 (CD19) chimeric antigen receptor (CD19 CAR) T-cell therapy in lymphoma, but the effects of zanubrutinib combined with CAR-T cells is unclear. Methods: We selected a low effect-target ratio (E:T = 1:3) to study this synergistic effect in vitro. The programed cell death protein 1 (PD-1) expression in CD19 CAR-T cells and immune phenotype of T lymphocytes were analyzed by flow cytometry (FCM). We selected CD19 CAR-T cells of a patient with diffuse large B cell lymphoma (DLBCL) to study the synergistic effect of zanubrutinib with CAR-T cells by bioluminescence imaging monitoring. The CD19 CAR-T cells expansion in mice was compared by FCM. Results: Zanubrutinib and ibrutinib had dose-dependent toxicity on both CAR-T cells and lymphoma cells. But there was no significant synergistic effect of the CD19 CAR-T cells combined with zanubrutinib/ibrutinib in vitro. The PD-1 expression in CD19 CAR-T cells increased when the CD19 CAR-T cells were co-cultured with Raji cells and decreased when ibrutinib was added in culture, but zanubrutinib had no such effect. The extinction of luciferase expression was more obvious in the polytherapy group of ibrutinib and CD19 CAR-T cell than that in the other groups. Moreover, the proportion of CAR-T cells in the combination therapy group of CD19 CAR-T cells and ibrutinib was higher than that of the polytherapy group of CD19 CAR-T cells with zanubrutinib group. The synergistic effect could be observed obviously in mice receiving ibrutinib combined with CD19 CAR-T cells. But zanubrutinib cannot perform joint therapy effect either in vitro or in mice. Conclusion: Zanubrutinib might have no joint therapy effect with CD19 CAR-T cells neither in vitro nor in mice, but the mechanism of different curative effects requires our further research and exploration.

PIK-75 overcomes venetoclax resistance via blocking PI3K-AKT signaling and MCL-1 expression in mantle cell lymphoma

Therapeutic resistance is the major challenge in clinic for patients with mantle cell lymphoma (MCL), an aggressive subtype of B-cell lymphoma. In addition to the FDA-approved Bruton's tyrosine kinase (BTK) inhibitors, multiple clinical trials have demonstrated clinical benefits in targeting BCL-2 by venetoclax and reported to greatly improve clinical outcome for refractory/relapsed patients with MCL alone or in combination with BTK inhibitors. However, resistance to venetoclax is no exception and marks as a new clinic challenge. To decode the underlying mechanisms driving venetoclax resistance, we established two MCL cell lines, Mino-Re and Rec1-Re, with acquired resistance to venetoclax from sensitive Mino and Rec-1. Using reverse phase protein assay (RPPA), an agnostic proteomic approach, we identified targetable signaling pathways that are associated with acquired venetoclax resistance in Mino-Re and Rec1-Re cells. A panel of pro-survival signals was identified to correlate well with venetoclax-resistance, including increased expression of MCL-1, BCL-xL and AKT phosphorylation, and decreased expression of BIM, BAX and PTEN. Based on a high throughput drug screening of over 320 FDA-approved/investigational drugs in the paired venetoclax-sensitive and -resistant cell lines Mino-Re and Rec1-Re, we identified the top candidates that are capable to overcome acquired venetoclax resistance in these cells. The best candidate is PIK-75, a dual inhibitor targeting both PI3K and CDK9. Its action to overcome venetoclax resistance was further confirmed in additional cell lines with primary venetoclax resistance (n=4) and primary patient samples (n=21). Mechanistically, PIK75 treatment potently diminished the elevated MCL-1 expression and AKT activation in cells with acquired or primary venetoclax resistance and resulted in potent anti-MCL activity to overcome these resistances. In addition, PIK75 is also potent in overcoming tumor microenvironment (TME)-associated venetoclax resistance. Furthermore, PIK-75 treatment is efficacious in overcoming primary and acquired venetoclax resistance in xenograft models and inhibited tumor cell dissemination to spleen in mice. Altogether, our data demonstrated that PIK-75 is highly potent in overcoming primary, acquired, or stromal cells-induced venetoclax resistances in MCL cells and revealed a new tumor vulnerability that can be exploited clinically in difficult to treat MCL cases, especially those with venetoclax resistance.

Distinct BTK inhibitors differentially induce apoptosis but similarly suppress chemotaxis and lipid accumulation in mantle cell lymphoma

Background

The more selective second-generation BTK inhibitors (BTKi) Acalabrutinib and Zanubrutinib and the first-generation BTKi Ibrutinib are highlighted by their clinical effectiveness in mantle cell lymphoma (MCL), however, similarities and differences of their biological and molecular effects on anti-survival of MCL cells induced by these BTKi with distinct binding selectivity against BTK remain largely unknown.

Methods

AlamarBlue assays were performed to define cytotoxicity of BTKi against MCL cells, Jeko-1 and Mino. Cleaved PARP and caspase-3 levels were examined by immunoblot analysis to study BTKi-induced apoptotic effects. Biological effects of BTKi on MCL-cell chemotaxis and lipid droplet (LD) accumulation were examined in Jeko-1, Mino and primary MCL cells via Transwell and Stimulated Raman scattering imaging analysis respectively. Enzyme-linked immunoassays were used to determine CCL3 and CCL4 levels in MCL-cell culture supernatants. RNA-seq analyses identified BTKi targets which were validated by quantitative RT-PCR (qRT-PCR) and immunoblot analysis.

Results

Acalabrutinib and Zanubrutinib induced moderate apoptosis in Ibrutinib high-sensitive JeKo-1 cells and Ibrutinib low-sensitive Mino cells, which was accompanied by cleaved PARP and caspase-3. Such effects might be caused by the stronger ability of Ibrutinib to upregulate the expression of pro-apoptotic genes, such as HRK, GADD45A, and ATM, in JeKo-1 cells than in Mino cells, and the expression of such apoptotic genes was slightly changed by Acalabrutinib and Zanubrutinib in both JeKo-1 and Mino cells. Further, Acalabrutinib, Zanubrutinib and Ibrutinib reduced MCL-cell chemotaxis with similar efficiency, due to their similar abilities to downmodulate chemokines, such as CCL3 and CCL4. Also, these three BTKi similarly suppressed MCL-cell LD accumulation via downregulating lipogenic factors, DGAT2, SCD, ENPP2 and ACACA without significant differences.

Conclusion

BTKi demonstrated differential capacities to induce MCL-cell apoptosis due to their distinct capabilities to regulate the expression of apoptosis-related genes, and similar biological and molecular inhibitory effects on MCL-cell chemotaxis and LD accumulation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08475-3.

Longitudinal single-cell profiling reveals molecular heterogeneity and tumor-immune evolution in refractory mantle cell lymphoma

The mechanisms driving therapeutic resistance and poor outcomes of mantle cell lymphoma (MCL) are incompletely understood. We characterize the cellular and molecular heterogeneity within and across patients and delineate the dynamic evolution of tumor and immune cell compartments at single cell resolution in longitudinal specimens from ibrutinib-sensitive patients and non-responders. Temporal activation of multiple cancer hallmark pathways and acquisition of 17q are observed in a refractory MCL. Multi-platform validation is performed at genomic and cellular levels in PDX models and larger patient cohorts. We demonstrate that due to 17q gain, BIRC5/survivin expression is upregulated in resistant MCL tumor cells and targeting BIRC5 results in marked tumor inhibition in preclinical models. In addition, we discover notable differences in the tumor microenvironment including progressive dampening of CD8+ T cells and aberrant cell-to-cell communication networks in refractory MCLs. This study reveals diverse and dynamic tumor and immune programs underlying therapy resistance in MCL.

Metabolic reprogramming toward oxidative phosphorylation identifies a therapeutic target for mantle cell lymphoma

Metabolic reprogramming is linked to cancer cell growth and proliferation, metastasis, and therapeutic resistance in a multitude of cancers. Targeting dysregulated metabolic pathways to overcome resistance, an urgent clinical need in all relapsed/refractory cancers, remains difficult. Through genomic analyses of clinical specimens, we show that metabolic reprogramming toward oxidative phosphorylation (OXPHOS) and glutaminolysis is associated with therapeutic resistance to the Bruton's tyrosine kinase inhibitor ibrutinib in mantle cell lymphoma (MCL), a B cell lymphoma subtype with poor clinical outcomes. Inhibition of OXPHOS with a clinically applicable small molecule, IACS-010759, which targets complex I of the mitochondrial electron transport chain, results in marked growth inhibition in vitro and in vivo in ibrutinib-resistant patient-derived cancer models. This work suggests that targeting metabolic pathways to subvert therapeutic resistance is a clinically viable approach to treat highly refractory malignancies.

Diagnosis and Treatment of Primary Cutaneous B-Cell Lymphomas: State of the Art and Perspectives

Primary cutaneous B-cell lymphomas are rare entities that develop primarily in the skin. They constitute a heterogeneous group that represents around a quarter of primary cutaneous lymphomas. The 2018 update of the World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) classification differentiates primary cutaneous marginal zone lymphoma and primary cutaneous follicle center lymphoma with an indolent course from primary cutaneous diffuse large B-cell lymphoma, leg type with an aggressive behavior. The broad spectrum of clinical presentations and the disease course marked by frequent relapses are diagnostic and therapeutic challenges. The classification of these diseases has been refined in recent years, which allows to better define their immunopathogenesis and specific management. In the present article, we review the main clinico-biological characteristics and the current therapeutic options of these three main subsets. Based on the recent therapeutic advances in nodal B-cell lymphomas, we focus on the development of novel treatment options applicable to primary cutaneous B-cell lymphomas, including targeted therapies, combination treatments and immunotherapeutic approaches, and cover basic, translational and clinical aspects aiming to improve the treatment of cutaneous B-cell lymphomas.

Influenza Virus Infections and Cellular Kinases

Influenza A viruses (IAVs) are a major cause of respiratory illness and are responsible for yearly epidemics associated with more than 500,000 annual deaths globally. Novel IAVs may cause pandemic outbreaks and zoonotic infections with, for example, highly pathogenic avian influenza virus (HPAIV) of the H5N1 and H7N9 subtypes, which pose a threat to public health. Treatment options are limited and emergence of strains resistant to antiviral drugs jeopardize this even further. Like all viruses, IAVs depend on host factors for every step of the virus replication cycle. Host kinases link multiple signaling pathways in respond to a myriad of stimuli, including viral infections. Their regulation of multiple response networks has justified actively targeting cellular kinases for anti-cancer therapies and immune modulators for decades. There is a growing volume of research highlighting the significant role of cellular kinases in regulating IAV infections. Their functional role is illustrated by the required phosphorylation of several IAV proteins necessary for replication and/or evasion/suppression of the innate immune response. Identified in the majority of host factor screens, functional studies further support the important role of kinases and their potential as host restriction factors. PKC, ERK, PI3K and FAK, to name a few, are kinases that regulate viral entry and replication. Additionally, kinases such as IKK, JNK and p38 MAPK are essential in mediating viral sensor signaling cascades that regulate expression of antiviral chemokines and cytokines. The feasibility of targeting kinases is steadily moving from bench to clinic and already-approved cancer drugs could potentially be repurposed for treatments of severe IAV infections. In this review, we will focus on the contribution of cellular kinases to IAV infections and their value as potential therapeutic targets.

Lenalidomide for the treatment of mantle cell lymphoma

INTRODUCTION

Although a variety of therapeutic schemes for Mantle Cell Lymphoma (MCL) have been attempted, the clinical outcome of patients continues to be unsatisfactory especially among patients with a very high-risk profile and in the relapsed/refractory setting. For this reason, recent clinical trials have explored novel approaches, either by the use of biological agents in chemotherapy-free schedules or by integrating them with chemoimmunotherapy regimens. Areas covered: The efficacy of lenalidomide monotherapy and combination therapy established in clinical studies mainly involving relapsed/refractory MCL is reviewed. The mechanism of action of lenalidomide is also discussed. Furthermore, the current position of lenalidomide in the MCL treatment algorithm is debated. Expert opinion: Lenalidomide demonstrated high efficacy and tolerability in several clinical trials as well as in retrospective real-world reports, even in patients who relapsed or were resistant to bortezomib and ibrutinib. In 2013, lenalidomide was approved by the Food and Drug Administration (FDA) for relapsed/refractory MCL after two prior therapies including at least one prior treatment with bortezomib. However, the potential synergistic anti-neoplastic effects of lenalidomide in combination with other biological agents, i.e. ibrutinib and venetoclax, especially in the management of p53-mutated cases, still remain an open issue.