Anti-CD20 antibody therapy for B-cell lymphomas

Smart Biomimetic Nanocomposites Mediate Mitochondrial Outcome through Aerobic Glycolysis Reprogramming: A Promising Treatment for Lymphoma

Toxicity and drug resistance caused by chemotherapeutic drugs have become bottlenecks in treating tumors. The delivery of anticancer drugs based on nanocarriers is regarded as an ideal way to solve the aforementioned problems. In this study, a new antilymphoma nanodrug CD20 aptamer-RBCm@Ag-MOFs/PFK15 (A-RAMP) is designed and constructed, and it consists of two parts: (1) metal-organic frameworks Ag-MOFs (AM) loaded with tumor aerobic glycolysis inhibitor PFK15 (P), forming a core part (AMP); (2) targeted molecule CD20 aptamer (A) is inserted into the red blood cell membrane (RBCm) to form the shell part (A-R). A-RAMP under the guidance of CD20 aptamer actively targets B-cell lymphoma both in vitro and in vivo. As a result, A-RAMP not only significantly inhibits the effect on tumor growth but also shows no obvious side effects on the treated nude mice, indicating that A-RAMP can accurately target tumor cells, reprogram aerobic glycolysis, and exert synergistic antitumor effect by Ag⁺ and PFK 15. Furthermore, the antitumor mechanism of A-RAMP in vivo by apoptotic pathway and targeting metabonomics are explored. These results suggest that A-RAMP has a promising application prospect as an smart, safe, effective, and synergistic antilymphoma agent.

Targeting innate sensing in the tumor microenvironment to improve immunotherapy

The innate immune sensing pathways play critical roles in the defense against pathogen infection, but their roles in cancer immunosurveillance and cancer therapies are less defined. We propose that defective innate immune sensing inside the tumor microenvironment might limit T-cell responses to immunotherapy. A recent mechanistic understanding of conventional therapies revealed that both innate immune sensing and T-cell responses are essential for optimal antitumor efficacy. T-cell-based immunotherapy, particularly immune checkpoint blockade, has achieved great success in reactivating antitumor immune responses to lead to tumor regression, but only in a small fraction of patients. Therefore, incorporating conventional therapy that can increase innate sensing and immunotherapy should lead to promising strategies for cancer patients. Here, we review the innate sensing pathways related to cancer initiation/progression and therapies, summarize the recent key findings in innate immune sensing related to conventional therapies, evaluate current combination strategies, and highlight the potential issues of combinational therapies in terms of antitumor efficacy and toxicities.

Single-Cell Gene Expression Analyses Reveal Distinct Self-Renewing and Proliferating Subsets in the Leukemia Stem Cell Compartment in Acute Myeloid Leukemia

Standard chemotherapy for acute myeloid leukemia (AML) targets proliferative cells and efficiently induces complete remission; however, many patients relapse and die of their disease. Relapse is caused by leukemia stem cells (LSC), the cells with self-renewal capacity. Self-renewal and proliferation are separate functions in normal hematopoietic stem cells (HSC) in steady-state conditions. If these functions are also separate functions in LSCs, then antiproliferative therapies may fail to target self-renewal, allowing for relapse. We investigated whether proliferation and self-renewal are separate functions in LSCs as they often are in HSCs. Distinct transcriptional profiles within LSCs of Mll-AF9/NRAS^G12V murine AML were identified using single-cell RNA sequencing. Single-cell qPCR revealed that these genes were also differentially expressed in primary human LSCs and normal human HSPCs. A smaller subset of these genes was upregulated in LSCs relative to HSPCs; this subset of genes constitutes "LSC-specific" genes in human AML. To assess the differences between these profiles, we identified cell surface markers, CD69 and CD36, whose genes were differentially expressed between these profiles. In vivo mouse reconstitution assays resealed that only CD69^High LSCs were capable of self-renewal and were poorly proliferative. In contrast, CD36^High LSCs were unable to transplant leukemia but were highly proliferative. These data demonstrate that the transcriptional foundations of self-renewal and proliferation are distinct in LSCs as they often are in normal stem cells and suggest that therapeutic strategies that target self-renewal, in addition to proliferation, are critical to prevent relapse and improve survival in AML. SIGNIFICANCE: These findings define and functionally validate a self-renewal gene profile of leukemia stem cells at the single-cell level and demonstrate that self-renewal and proliferation are distinct in AML. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/3/458/F1.large.jpg.

Chronic lymphocytic leukemia: 2020 update on diagnosis, risk stratification and treatment

DISEASE OVERVIEW

Chronic lymphocytic leukemia (CLL) is the commonest leukemia in western countries. The disease typically occurs in elderly patients and has a highly variable clinical course. Leukemic transformation is initiated by specific genomic alterations that impair apoptosis of clonal B-cells.

DIAGNOSIS

The diagnosis is established by blood counts, blood smears, and immunophenotyping of circulating B-lymphocytes, which identify a clonal B-cell population carrying the CD5 antigen, as well as typical B-cell markers.

PROGNOSIS

The two similar clinical staging systems, Rai and Binet, create prognostic information by using results of physical examination and blood counts. Various biological and genetic markers also have prognostic value. Deletions of the short arm of chromosome 17 (del [17p]) and/or mutations of the TP53 gene, predict resistance to chemoimmunotherapy and a shorter time to progression, with most targeted therapies. A comprehensive, international prognostic score (CLL-IPI) integrates genetic, biological and clinical variables to identify distinct risk groups of CLL patients.

THERAPY

Only patients with active or symptomatic disease, or with advanced Binet or Rai stages require therapy. When treatment is indicated, several options exist for most CLL patients: a combination of venetoclax with obinutuzumab, ibrutinib monotherapy, or chemoimmunotherapy. For physically fit patients younger than 65 (in particular when presenting with a mutated IGVH gene), chemoimmunotherapy with fludarabine, cyclophosphamide and rituximab remains a standard therapy, since it may have curative potential. At relapse, the initial treatment may be repeated, if the treatment-free interval exceeds 3 years. If the disease relapses earlier, therapy should be changed using an alternative regimen. Patients with a del (17p) or TP53 mutation are a different, high-risk category and should be treated with targeted agents. An allogeneic SCT may be considered in relapsing patients with TP53 mutations or del (17p), or patients that are refractory to inhibitor therapy.

FUTURE CHALLENGES

Targeted agents (ibrutinib, idelalisib, venetoclax, obinutuzumab) will be increasingly used in combination to allow for short, but potentially definitive therapies of CLL. It remains to be proven that they generate a superior outcome when compared to monotherapies with inhibitors of Bruton tyrosine kinase, which can also yield long-lasting remissions. Moreover, the optimal sequencing of drug combinations is unknown. Therefore, CLL patients should be treated in clinical trials whenever possible.

PKPD Assessment of the Anti-CD20 Antibody Obinutuzumab in Cynomolgus Monkey is Feasible Despite Marked Anti-Drug Antibody Response in This Species

The pharmacokinetics (PK) of the anti-CD20 monoclonal antibody obinutuzumab was assessed after single intravenous dosing to cynomolgus monkeys. In addition, the pharmacokinetic-pharmacodynamic (PKPD) relationship for B-cell depletion was characterized. The PKPD model was used to estimate the B-cell repopulation during the recovery phase of chronic toxicology studies, thereby supporting the study design, in particular planning the recovery phase duration. Marked immunogenicity against obinutuzumab was observed approximately 10 days after single dose, leading to an up to ∼30-fold increase in obinutuzumab clearance in the affected monkeys. Despite this accelerated clearance, the PK could be characterized, either by disregarding the clearance in noncompartmental PK analysis or by capturing it explicitly as an additional time-dependent clearance process in compartmental modeling. This latter step was crucial to model the PKPD of B-cells as an indirect response to obinutuzumab exposure, showing that-without immune response-the limiting factor is obinutuzumab elimination with concentrations below 0.02 μg/mL required for initiation of B-cell recovery. Overall, the results demonstrate that despite a marked anti-drug antibody response in the nonclinical animal species, the PK and PKPD of obinutuzumab could be characterized successfully by appropriately addressing the immune-modulated clearance pathway in data analysis and modeling.

Novel Immunotherapies for T Cell Lymphoma and Leukemia

PURPOSE OF REVIEW

Novel immunotherapies such as checkpoint inhibitors, bispecific antibodies, and chimeric antigen receptor T cells are leading to promising responses when treating solid tumors and hematological malignancies. T cell neoplasms include leukemia and lymphomas that are derived from T cells and overall are characterized by poor clinical outcomes. This review describes the rational and preliminary results of immunotherapy for patients with T cell lymphoma and leukemia.

RECENT FINDINGS

For T cell neoplasms, despite significant research effort, only few agents, such as monoclonal antibodies and allogeneic stem cell transplantation, showed some clinical activity. One of the major hurdles to targeting T cell neoplasms is that activation or elimination of T cells, either normal or neoplastic, can cause significant toxicity. A need to develop novel safe and effective immunotherapies for T cell neoplasms exists. In this review, we will discuss the rationale for immunotherapy of T cell leukemia and lymphoma and present the most recent therapeutic approaches.

Examination of CD302 as a potential therapeutic target for acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common form of adult acute leukemia with ~20,000 new cases yearly. The disease develops in people of all ages, but is more prominent in the elderly, who due to limited treatment options, have poor overall survival rates. Monoclonal antibodies (mAb) targeting specific cell surface molecules have proven to be safe and effective in different haematological malignancies. However, AML target molecules are currently limited so discovery of new targets would be highly beneficial to patients. We examined the C-type lectin receptor CD302 as a potential therapeutic target for AML due to its selective expression in myeloid immune populations. In a cohort of 33 AML patients with varied morphological and karyotypic classifications, 88% were found to express CD302 on the surface of blasts and 80% on the surface of CD34⁺ CD38^- population enriched with leukemic stem cells. A mAb targeting human CD302 was effective in mediating antibody dependent cell cytotoxicity and was internalised, making it amenable to toxin conjugation. Targeting CD302 with antibody limited in vivo engraftment of the leukemic cell line HL-60 in NOD/SCID mice. While CD302 was expressed in a hepatic cell line, HepG2, this molecule was not detected on the surface of HepG2, nor could HepG2 be killed using a CD302 antibody-drug conjugate. Expression was however found on the surface of haematopoietic stem cells suggesting that targeting CD302 would be most effective prior to haematopoietic transplantation. These studies provide the foundation for examining CD302 as a potential therapeutic target for AML.

Targeting the Antibody Checkpoints to Enhance Cancer Immunotherapy-Focus on FcγRIIB

Immunotherapy with therapeutic antibodies has increased survival for patients with hematologic and solid cancers. Still, a significant fraction of patients fails to respond to therapy or acquire resistance. Understanding and overcoming mechanisms of resistance to antibody drugs, and in particular those common to antibody drugs as a class, is therefore highly warranted and holds promise to improve response rates, duration of response and potentially overall survival. Activating and inhibitory Fc gamma receptors (FcγR) are known to coordinately regulate therapeutic activity of tumor direct-targeting antibodies. Similar, but also divergent, roles for FcγRs in controlling efficacy of immune modulatory antibodies e.g., checkpoint inhibitors have been indicated from mouse studies, and were recently implicated in contributing to efficacy in the human clinical setting. Here we discuss evidence and mechanisms by which Fc gamma receptors–the “antibody checkpoints”–regulate antibody-induced antitumor immunity. We further discuss how targeted blockade of the sole known inhibitory antibody checkpoint FcγRIIB may help overcome resistance and boost activity of clinically validated and emerging antibodies in cancer immunotherapy.

BReDi mouse: A novel transgenic mouse strain to track and deplete B cells

BReDi mice express a red fluorescent protein together with the diphtheria toxin receptor selectively in B cells. B cells can be effectively visualized by red fluorescence and can be efficiently depleted in a highly controlled fashion to study their functional capacity in vivo.

CUL4B regulates autophagy via JNK signaling in diffuse large B-cell lymphoma

Aberrant expression of CUL4B was identified in various types of solid cancers. Cumulative evidences support the oncogenic role of CUL4B in cancers, including regulation of cell proliferation and signal transduction. However, its clinical value and potential pathogenic mechanism in diffuse large B-cell lymphoma (DLBCL) have not been described previously. Therefore, we hypothesize that overexpressed CUL4B may contribute to the pathogenesis of DLBCL. The aim of this study is to assess the expression and the biological function of CUL4B in DLBCL progression. In our study, CUL4B overexpression was observed in DLBCL tissues, and its upregulation was closely associated with poor prognosis in patients. Furthermore, the functional roles of CUL4B was detected both in vitro and in vivo. We demonstrated that silencing CUL4B could not only induce cell proliferation inhibition, cell cycle arrest, and motility attenuation of DLBCL cells in vitro, but also decrease tumor growth in DLBCL xenografts mice. In addition, we identified that CUL4B may act as a potent inductor of JNK phosphorylation in regulation of autophagy. Our findings demonstrated a significant role of CUL4B in the development and progression of DLBCL. CUL4B may act as a useful biomarker and a novel therapeutic target in DLBCL.

Insulin-like Growth Factor-I Receptor and Thyroid-Associated Ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is a complex disease process presumed to emerge from autoimmunity occurring in the thyroid gland, most frequently in Graves disease (GD). It is disfiguring and potentially blinding, culminating in orbital tissue remodeling and disruption of function of structures adjacent to the eye. There are currently no medical therapies proven capable of altering the clinical outcome of TAO in randomized, placebo-controlled multicenter trials. The orbital fibroblast represents the central target for immune reactivity. Recent identification of fibroblasts that putatively originate in the bone marrow as monocyte progenitors provides a plausible explanation for why antigens, the expressions of which were once considered restricted to the thyroid, are detected in the TAO orbit. These cells, known as fibrocytes, express relatively high levels of functional TSH receptor (TSHR) through which they can be activated by TSH and the GD-specific pathogenic antibodies that underpin thyroid overactivity. Fibrocytes also express insulin-like growth factor I receptor (IGF-IR) with which TSHR forms a physical and functional signaling complex. Notably, inhibition of IGF-IR activity results in the attenuation of signaling initiated at either receptor. Some studies suggest that IGF-IR-activating antibodies are generated in GD, whereas others refute this concept. These observations served as the rationale for implementing a recently completed therapeutic trial of teprotumumab, a monoclonal inhibitory antibody targeting IGF-IR in TAO. Results of that trial in active, moderate to severe disease revealed dramatic and rapid reductions in disease activity and severity. The targeting of IGF-IR with specific biologic agents may represent a paradigm shift in the therapy of TAO.

Immunotherapy in myeloma: how far have we come?

The treatment of multiple myeloma (MM) has evolved substantially over the past decades, leading to a significantly improved outcome of MM patients. The introduction of high-dose therapy, especially, and autologous stem cell transplantation, as well as the development of new drugs, such as immunomodulatory drugs (IMiDs) and proteasome inhibitors have contributed to the improvement in survival. However, eventually most MM patients relapse, which indicates that there is a need for new agents and novel treatment strategies. Importantly, the long-term survival in a subset of MM patients after allogeneic stem cell transplantation illustrates the potential of immunotherapy in MM, but allogeneic stem cell transplantation is also associated with a high rate of treatment-related mortality. Recently, a better insight into several immune-evasion mechanisms, which contribute to tumor progression, has resulted in the development of active and well-tolerated novel forms of immunotherapy. These immunotherapeutic agents can be used as monotherapy, or, even more successfully, in combination with other established anti-MM agents to further improve depth and duration of response by preventing the outgrowth of resistant clones. This review will discuss the mechanisms used by MM cells to evade the immune system, and also provide an overview of currently approved immunotherapeutic drugs, such as IMiDs (e.g. lenalidomide and pomalidomide) and monoclonal antibodies that target cell surface antigens present on the MM cell (e.g. elotuzumab and daratumumab), as well as novel immunotherapies (e.g. chimeric antigen receptor T-cells, bispecific antibodies and checkpoint inhibitors) currently in clinical development in MM.

Drug-free macromolecular therapeutics induce apoptosis in cells isolated from patients with B cell malignancies with enhanced apoptosis induction by pretreatment with gemcitabine

Drug-free macromolecular therapeutics (DFMT) is a new paradigm for the treatment of B cell malignancies. Apoptosis is initiated by the biorecognition of complementary oligonucleotide motifs at the cell surface resulting in crosslinking of CD20 receptors. DMFT is composed from two nanoconjugates: 1) bispecific engager, Fab'-MORF1 (anti-CD20 Fab' fragment conjugated with morpholino oligonucleotide), and 2) a crosslinking (effector) component P-(MORF2)_X (N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer grafted with multiple copies of complementary morpholino oligonucleotide). We evaluated this concept in 44 samples isolated from patients diagnosed with various subtypes of B cell malignancies. Apoptosis was observed in 65.9% of the samples tested. Pretreatment of cells with gemcitabine (GEM) or polymer-gemcitabine conjugate (2P-GEM) enhanced CD20 expression levels thus increasing apoptosis induced by DFMT. These positive results demonstrated that DFMT has remarkable therapeutic potential in various subtypes of B cell malignancies.

Cellular Immunotherapy in the Treatment of Hematopoietic Malignancies

Cancer immunotherapy has been shown to be an efficacious therapeutic approach in the treatment of cancers including hematopoietic malignancies. Induction of T cell cytotoxicity against tumors by adoptive cell therapies (ACT), cancer vaccines, gene therapies, and monoclonal antibody therapies has been intensively studied. In particular, immune checkpoint blockade and chimeric antigen receptor T (CAR-T) cell therapies are the recent clinical successes in cancer immunotherapy. This article introduces the main concepts and addresses the most relevant clinical modalities of cellular immunotherapies for hematological malignancies: antigen non-specific T cell therapy, genetically modified T cell receptor (TCR) T cell therapy, chimeric antigen receptor (CAR) T cell therapy, and CAR-T cell clinical trials in leukemia, lymphoma, and multiple myeloma. Clinical trials have shown encouraging results, but future studies may need to incorporate novel CAR constructs or targets with enhanced safety and efficacy to ensure long-term benefits.

Humanization and Simultaneous Optimization of Monoclonal Antibody

Antibody humanization is an essential technology for reducing the potential risk of immunogenicity associated with animal-derived antibodies and has been applied to a majority of the therapeutic antibodies on the market. For developing an antibody molecule as a pharmaceutical at the current biotechnology level, however, other properties also have to be considered in parallel with humanization in antibody generation and optimization. This section describes the critical properties of therapeutic antibodies that should be sufficiently qualified, including immunogenicity, binding affinity, physicochemical stability, expression in host cells and pharmacokinetics, and the basic methodologies of antibody engineering involved. By simultaneously optimizing the antibody molecule in light of these properties, it should prove possible to shorten the research and development period necessary to identify a highly qualified clinical candidate and consequently accelerate the start of the clinical trial.

Monoclonal Antibodies: Past, Present and Future

Monoclonal antibodies (mAbs) are immunoglobulins designed to target a specific epitope on an antigen. Immunoglobulins of identical amino-acid sequence were originally produced by hybridomas grown in culture and, subsequently, by recombinant DNA technology using mammalian cell expression systems. The antigen-binding region of the mAb is formed by the variable domains of the heavy and light chains and contains the complementarity-determining region that imparts the high specificity for the target antigen. The pharmacokinetics of mAbs involves target-mediated and non-target-related factors that influence their disposition.Preclinical safety evaluation of mAbs differs substantially from that of small molecular (chemical) entities. Immunogenicity of mAbs has implications for their pharmacokinetics and safety. Early studies of mAbs in humans require careful consideration of the most suitable study population, route/s of administration, starting dose, study design and the potential difference in pharmacokinetics in healthy subjects compared to patients expressing the target antigen.Of the ever-increasing diversity of therapeutic indications for mAbs, we have concentrated on two that have proved dramatically successful. The contribution that mAbs have made to the treatment of inflammatory conditions, in particular arthritides and inflammatory bowel disease, has been nothing short of revolutionary. Their benefit has also been striking in the treatment of solid tumours and, most recently, as immunotherapy for a wide variety of cancers. Finally, we speculate on the future with various new approaches to the development of therapeutic antibodies.

Ocrelizumab for the treatment of multiple sclerosis

INTRODUCTION

In the past decade, the role of B cells in the pathogenesis of multiple sclerosis (MS) is coming to the forefront. Depletion of B cells by anti-CD20 monoclonal antibodies (mAbs) has proved to decrease the activity of the relapsing-remitting MS (RRMS) and the progression of primary progressive MS (PPMS). Areas covered: In this review, the authors discuss the rationale of the depletion of B cells in RRMS and PPMS across recent studies on the role of B cells in the pathogenesis of MS; previous clinical trials with treatments targeting B cells; the mechanism of action of ocrelizumab - a second generation anti-CD20 mAb - and recent phase III clinical trials with ocrelizumab in RRMS and PPMS. Expert commentary: Ocrelizumab is the first anti-CD20 monoclonal antibody approved for RRMS and the first treatment approved for PPMS. The long-term effect and safety profile need to be evaluated in extension of clinical trials and in real-world studies.

The applications of anti-CD20 antibodies to treat various B cells disorders

B-lymphocyte antigen CD20 (called CD20) is known as an activated-glycosylated phosphoprotein which is expressed on the surface of all B-cells. CD20 is involved in the regulation of trans-membrane Ca²⁺ conductance and also play critical roles in cell-cycle progression during human B cell proliferation and activation. The appearance of monoclonal antibody (mAb) technology provided an effective field for targeted therapy in treatment of a variety of diseases such as cancer, and autoimmune diseases. Anti-CD20 is one of important antibodies which could be employed in treatment of several diseases. Increasing evidences revealed that efficacy of different anti-CD20 antibodies is implicated by their function. Hence, evaluation of anti-CD20 antibodies function could provide and introduce new anti-CD20 based therapies. In the present study, we summarized several applications of anti-CD20 antibodies in various immune related disorders including B-CLL (B-cell chronic lymphocytic leukemia), rheumatoid arthritis (RA), multiple sclerosis (MS) and melanoma.

Human Serum Albumin-Based Drug-Free Macromolecular Therapeutics: Apoptosis Induction by Coiled-Coil-Mediated Cross-Linking of CD20 Antigens on Lymphoma B Cell Surface

A therapeutic platform-drug-free macromolecular therapeutics (DFMT)-that induces apoptosis in B cells by cross-linking of CD20 receptors, without the need for low molecular weight cytotoxic drug, is developed. In this report, a DFMT system is synthesized and evaluated based on human serum albumin (HSA) and two complementary coiled-coil forming peptides, CCE and CCK. Fab' fragment of anti-CD20 monoclonal antibody rituximab is attached to CCE (Fab'-CCE); multiple grafts of CCK are conjugated to HSA (HSA-(CCK)7 ). The colocalization of both nanoconjugates at the surface of non-Hodgkin's lymphoma (NHL) Raji cells is demonstrated by confocal fluorescence microscopy. The colocalization leads to coiled-coil formation, CD20 cross-linking, and apoptosis induction. The apoptotic levels are evaluated by Annexin V, Caspase 3, and terminal deoxynucleotidyl transferase dUTP nick end labeling assays. Selective surface binding of DFMT to CD20+ cells is validated in experiments on a coculture of CD20+ (Raji) and CD20-(DG-75) cells. It is found that DFMT can trigger calcium influx only in Raji cells, but not in DG-75 cells. A highly specific treatment for NHL and other B cell malignancies with considerable translational potential is presented by HSA-based DFMT system.

Targeting tumor cells with antibodies enhances anti-tumor immunity

Tumor-targeting antibodies were initially defined as a group of therapeutic monoclonal antibodies (mAb) that recognize tumor-specific membrane proteins, block cell signaling, and induce tumor-killing through Fc-driven innate immune responses. However, in the past decade, ample evidence has shown that tumor-targeting mAb (TTmAb) eradicates tumor cells via activation of cytotoxic T cells (CTLs). In this review, we specifically focus on how TTmAbs induce adaptive anti-tumor immunity and its potential in combination therapy with immune cytokines, checkpoint blockade, radiation, and enzyme-targeted small molecule drugs. Exploring the mechanisms of these preclinical studies and retrospective clinical data will significantly benefit the development of highly efficient and specific TTmAb-oriented anti-tumor remedies.

The efficacy and safety of anti-CD19/CD20 chimeric antigen receptor- T cells immunotherapy in relapsed or refractory B-cell malignancies:a meta-analysis

BACKGROUND

Chimeric antigen receptor T (CAR T) cells immunotherapy is rapidly developed in treating cancers, especially relapsed or refractory B-cell malignancies.

METHODS

To assess the efficacy and safety of CAR T therapy, we analyzed clinical trials from PUBMED and EMBASE.

RESULTS

Results showed that the pooled response rate, 6-months and 1-year progression-free survival (PFS) rate were 67%, 65.62% and 44.18%, respectively. We observed that received lymphodepletion (72% vs 44%, P = 0.0405) and high peak serum IL-2 level (85% vs 31%, P = 0.04) were positively associated with patients' response to CAR T cells. Similarly, costimulatory domains (CD28 vs CD137) in second generation CAR T was positively associated with PFS (52.69% vs 33.39%, P = 0.0489). The pooled risks of all grade adverse effects (AEs) and grade ≥ 3 AEs were 71% and 43%. Most common grade ≥ 3 AEs were fatigue (18%), night sweats (14%), hypotension (12%), injection site reaction (12%), leukopenia (10%), anemia (9%).

CONCLUSIONS

In conclusion, CAR T therapy has promising outcomes with tolerable AEs in relapsed or refractory B-cell malignancies. Further modifications of CAR structure and optimal therapy strategy in continued clinical trials are needed to obtain significant improvements.

All-trans retinoic acid-encapsulated, CD20 antibody-conjugated poly(lactic-co-glycolic acid) nanoparticles effectively target and eliminate melanoma-initiating cells in vitro

Purpose

Melanoma, which is initiated from melanocytes, is the most fatal type of skin cancer. Melanoma-initiating cells significantly contribute to the initiation, metastasis, and recurrence of melanoma, and CD20 is a marker of melanoma-initiating cells. All-trans retinoic acid (ATRA) has been demonstrated to induce differentiation, inhibit proliferation, and promote the apoptosis of cancer cells and cancer-initiating cells (CICs). However, there has been no report on ATRA activity against melanoma-initiating cells. In this study, we examined the activity of ATRA against melanoma-initiating cells and developed ATRA-encapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles, which were conjugated with a CD20 antibody (ATRA-PNP-CD20) for targeted delivery of ATRA to CD20⁺ melanoma-initiating cells.

Materials and methods

The effects of ATRA and ATRA-PNP-CD20 against melanoma-initiating cells were investigated using a cytotoxicity assay, tumorsphere formation assay, and flow cytometry.

Results

ATRA-PNP-CD20 had a size of 126.9 nm and a negative zeta potential. The drug-loading capacity of ATRA-PNP-CD20 was 8.7%, and ATRA-PNP-CD20 displayed a sustained release of ATRA for 144 hours. The results showed that ATRA-PNP-CD20 could effectively and specifically deliver ATRA to CD20⁺ melanoma-initiating cells, achieving superior inhibitory effects against CD20⁺ melanoma-initiating cells compared with those of free ATRA and nontargeted nanoparticles. To the best of our knowledge, we report for the first time a potent activity of ATRA against CD20⁺ melanoma-initiating cells, targeted drug delivery of ATRA via nanoparticles to melanoma-initiating cells, and the achievement of a superior inhibitory effect against melanoma-initiating cells by using a CD20 antibody.

Conclusion

ATRA-PNP-CD20 represents a promising tool for eliminating melanoma-initiating cells and shows a potential for the therapy of melanoma.

Case report presenting the diagnostic challenges in a patient with recurrent acquired angioedema, antiphospholipid antibodies and undetectable C2 levels

Background

Angioedema secondary to acquired C1 inhibitor deficiency (AAE) is a rare disease. It usually is associated with lymphoproliferative disorders. We present a case of AAE in a patient with antiphospholipid syndrome (APS), a non-Hodgkin lymphoproliferative disorder (NHL) with undetectable levels of C2, C4, and an undetectable CH50. The co-existence of AAE, APS, and NHL, with an undetectable C2 level, to the best of our knowledge, has never before reported together in the same patient.

Case presentation

A patient with a recent history of thrombosis presented with recurrent episodes of angioedema. The workup revealed undetectable levels of C2, C4 and undetectable CH50. Quantitative levels of C1 inhibitor and C1q were low. C1 inhibitor function was less than 40%. Anti-cardiolipin antibodies were found. The patient was initially treated on demand with intravenous plasma-derived human C1-INH concentrates, (Cinryze^® Shire). Later the patient received prophylactic therapy with danazol. She was diagnosed with lymphoma 3 years after her first episode of angioedema. Single agent therapy with rituximab was not only effective in treating her lymphoma but also preventing further episodes of angioedema. Anti-cardiolipin antibody titers also declined. Additionally, marked early primary pathway complement component abnormalities and CH50 also corrected, although incomplete normalization of C4 proved to be due to a heterozygous C4 deficiency.

Conclusion

This case shows the unique association of AAE, APS and NHL in a patient with undetectable levels of early complement components. Additionally, this case also shows for the first time the effectiveness of rituximab therapy in all three disease states while co-existing simultaneously in the same patient.

Successful Use of a Multidisciplinary Approach to Treat a Perforated Duodenal Malignant Lymphoma in an Elderly Patient

Treatment of duodenal malignant lymphoma is difficult due to life-threatening complications such as intestinal obstruction, perforation, and pancreatitis. Thus, multidisciplinary procedures are required alongside surgical intervention. Contrast abdominal CT images of a 75-year-old female suffering from vomiting revealed thickening of the duodenal wall (from the second to third segment). Gastrojejunostomy and biopsy identified the tumor as diffuse large B-cell lymphoma. A diagnosis of stage II duodenal lymphoma was made. The lymphoma continued to grow, resulting in jaundice and intestinal perforation, which was first treated with two cycles of rituximab and antibiotics. Thereafter, less intensive chemotherapy (two cycles each of R-mini-CHP, CHP, and R-CHOP) was administered, which led to significant improvement upon assessment by PET-CT. Residual lymphoma was treated with consolidation radiotherapy (50 Gy in 25 fractions) over 5 weeks after chemotherapy. The patient attained a complete response and has been disease-free for more than 4 years. Thus, duodenal perforated lymphoma can be treated successfully using a multidisciplinary approach that combines surgery, immunochemotherapy, and radiation therapy.

Serological Immunoglobulin-Free Light Chain Profile in Myasthenia Gravis Patients

Background

Serological levels of free immunoglobulin light chains (FLCs), produced in excess of heavy chains during synthesis of immunoglobulins by plasma cells, can be considered a direct marker of B cell activity in different systemic inflammatory-autoimmune conditions and may represent a useful predictor of rituximab (RTX) therapeutic efficacy, as reported for rheumatoid arthritis and systemic lupus erythematosus. Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction with antibodies (abs) targeting the acetylcholine receptor (AChR) or the muscle-specific tyrosine kinase (MuSK), inducing muscle weakness and excessive fatigability. As MG course may be remarkably variable, we evaluated the possible use of FLCs as biomarkers of disease activity.

Subjects and Methods

We assessed FLC levels in 34 sera from 17 AChR-MG and from 13 MuSK-MG patients, in comparison with 20 sera from patients with systemic autoimmune rheumatic diseases and 18 from healthy blood donors, along with titers of specific auto-abs and IgG subclass distribution.

Results

We found a statistically significant increase in free κ chains in both AChR- and MuSK-MG patients, while free λ chain levels were increased only in AChR-MG. We also observed a significant reduction of both free κ and λ chains in 1/4 MuSK-MG patients along with specific abs titer, two months after RTX treatment.

Conclusions

From our data, FLCs appear to be a sensitive marker of B cell activation in MG. Further investigations are necessary to exploit their potential as reliable biomarkers of disease activity.

CD38-targeting antibodies in multiple myeloma: mechanisms of action and clinical experience

INTRODUCTION

Multiple myeloma (MM) is generally an incurable hematological malignancy with heterogeneous overall survival rates ranging from a few months to more than 10 years. Survival is especially poor for patients who developed disease that is refractory to immunomodulatory drugs and proteasome inhibitors. Areas covered: This review will discuss the importance of CD38-targeting antibodies for the treatment of MM patients to improve their outcome. Expert commentary: Intense immuno-oncological laboratory research has resulted in the development of functionally active monoclonal antibodies against cell surface markers present on MM cells. In this respect, CD38-targeting antibodies such as daratumumab, MOR202, and isatuximab, have high single agent activity in heavily pretreated MM patients by virtue of their pleiotropic mechanisms of action including Fc-dependent effector mechanisms and immunomodulatory activities. Importantly, CD38-targeting antibodies are well tolerated, with infusion reactions as most frequent adverse event. Altogether, this makes them attractive combination partners with other anti-MM agents. Daratumumab is already approved as monotherapy and in combination with lenalidomide-dexamethasone as well as bortezomib-dexamethasone in pretreated MM patients. Furthermore, results from studies evaluating CD38-targeting antibodies in newly diagnosed MM patients are also promising, indicating that CD38-targeting antibodies will be broadly used in MM, resulting in further improvements in survival.

New insights in Type I and II CD20 antibody mechanisms-of-action with a panel of novel CD20 antibodies

Based on their mechanisms-of-action, CD20 monoclonal antibodies (mAbs) are grouped into Type I [complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC)] and Type II [programmed cell death (PCD) and ADCC] mAbs. We generated 17 new hybridomas producing CD20 mAbs of different isotypes and determined unique heavy and light chain sequence pairs for 13 of them. We studied their epitope binding, binding kinetics and structural properties and investigated their predictive value for effector functions, i.e. PCD, CDC and ADCC. Peptide mapping and CD20 mutant screens revealed that 10 out of these 11 new mAbs have an overlapping epitope with the prototypic Type I mAb rituximab, albeit that distinct amino acids of the CD20 molecule contributed differently. Binding kinetics did not correlate with the striking differences in CDC activity among the mIgG2c mAbs. Interestingly, chimerization of mAb m1 resulted in a mAb displaying both Type I and II characteristics. PCD induction was lost upon introduction of a mutation in the framework of the heavy chain affecting the elbow angle, supporting that structural changes within this region can affect functional activities of CD20 mAbs. Together, these new CD20 mAbs provide further insights in the properties dictating the functional efficacy of CD20 mAbs.

Salinomycin-loaded lipid-polymer nanoparticles with anti-CD20 aptamers selectively suppress human CD20+ melanoma stem cells

Melanoma is the deadliest type of skin cancer. CD20+ melanoma stem cells (CSCs) are pivotal for metastasis and initiation of melanoma. Therefore, selective elimination of CD20+ melanoma CSCs represents an effective treatment to eradicate melanoma. Salinomycin has emerged as an effective drug toward various CSCs. Due to its poor solubility, its therapeutic efficacy against melanoma CSCs has never been evaluated. In order to target CD20+ melanoma CSCs, we designed salinomycin-loaded lipid-polymer nanoparticles with anti-CD20 aptamers (CD20-SA-NPs). Using a single-step nanoprecipitation method, salinomycin-loaded lipid-polymer nanoparticles (SA-NPs) were prepared, then CD20-SA-NPs were obtained through conjugation of thiolated anti-CD20 aptamers to SA-NPs via a maleimide-thiol reaction. CD20-SA-NPs displayed a small size of 96.3 nm, encapsulation efficiency higher than 60% and sustained drug release ability. The uptake of CD20-SA-NPs by CD20+ melanoma CSCs was significantly higher than that of SA-NPs and salinomycin, leading to greatly enhanced cytotoxic effects in vitro, thus the IC₅₀ values of CD20-SA-NPs were reduced to 5.7 and 2.6 μg/mL in A375 CD+20 cells and WM266-4 CD+ cells, respectively. CD20-SA-NPs showed a selective cytotoxicity toward CD20+ melanoma CSCs, as evidenced by the best therapeutic efficacy in suppressing the formation of tumor spheres and the proportion of CD20+ cells in melanoma cell lines. In mice bearing melanoma xenografts, administration of CD20-SA-NPs (salinomycin 5 mg·kg^-1·d^-1, iv, for 60 d) showed a superior efficacy in inhibition of melanoma growth compared with SA-NPs and salinomycin. In conclusion, CD20 is a superior target for delivering drugs to melanoma CSCs. CD20-SA-NPs display effective delivery of salinomycin to CD20+ melanoma CSCs and represent a promising treatment for melanoma.

Development and characterization of an anti-rituximab monoclonal antibody panel

During the development of monoclonal antibodies (mAbs) and other therapeutic proteins, immunogenicity, in particular the induction of anti-drug antibodies (ADAs), is an important concern, and thus immunogenicity assessment is a requirement for their approval. Establishment of appropriate methods for detecting and characterizing ADAs is necessary for immunogenicity assessment, but the lack of commonly available reference standards makes it difficult to compare and evaluate the methods. It is also difficult to compare the data with those obtained by other methods or facilities without reference standards. Here, we developed a panel of ADAs against anti-CD20 rituximab (Rituxan®, MabThera®); the panel consisted of eight clones of recombinant human-rat chimeric mAbs that target rituximab. The anti-rituximab mAbs showed different binding properties (specificity, epitope and affinity), and different neutralization potencies for CD20 binding, complement-dependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity. The molecular size of the immune complex consisting of rituximab and the anti-rituximab mAb differed among the clones, and was well correlated with their level of Fcγ-receptor activation. These results suggest that the ADAs chosen for the newly developed panel are suitable surrogates for human ADAs, which exhibit different potential to affect the efficacy and safety of rituximab. Next, we used this panel to compare several ADA-detecting assays and revealed that the assays had different abilities to detect the ADAs with different binding characteristics. We conclude that our panel of ADAs against rituximab will be useful for the future development and characterization of assays for immunogenicity assessment.

CD20 role in pathophysiology of Hodgkin's disease

Hodgkin's lymphoma (HL) is a tumor comprising non-malignant and malignant B-cells. Classical HL expresses CD15+ and CD30+ antigens, and 20 to 40% of patients are CD20+. This antigen is a ligand free protein present in B lymphocyte cells and its function is not well known. Some studies suggest that expression of CD20 may play a major role in Hodgkin's disease pathophysiology and may affect the patients' treatment prognosis, as well as relapse and refractory response. In the past few years, development of monoclonal anti-CD20 antibodies changed drastically the treatment for non-Hodgkin lymphomas in which CD20 is expressed. HL treatment is essentially composed of radiotherapy and chemotherapy; however, monoclonal anti-CD20 antibodies applicability is not well delimitated due to lack of information about clinical outcomes with anti-CD20 monotherapy or combined drug therapy using a classic regimen, as well as about CD20 pathophysiology mechanisms in B-cells tumors. The objective of our review is to discuss CD20 function in Hodgkin's lymphoma development, its influence on disease evolution and outcomes, as well as its effects on therapeutics and patients' prognostic.

Mantle cell lymphoma in the era of precision medicine-diagnosis, biomarkers and therapeutic agents

Despite advances in the development of clinical agents for treating Mantle Cell Lymphoma (MCL), treatment of MCL remains a challenge due to complexity and frequent relapse associated with MCL. The incorporation of conventional and novel diagnostic approaches such as genomic sequencing have helped improve understanding of the pathogenesis of MCL, and have led to development of specific agents targeting signaling pathways that have recently been shown to be involved in MCL. In this review, we first provide a general overview of MCL and then discuss about the role of biomarkers in the pathogenesis, diagnosis, prognosis, and treatment for MCL. We attempt to discuss major biomarkers for MCL and highlight published and ongoing clinical trials in an effort to evaluate the dominant signaling pathways as drugable targets for treating MCL so as to determine the potential combination of drugs for both untreated and relapse/refractory cases. Our analysis indicates that incorporation of biomarkers is crucial for patient stratification and improve diagnosis and predictability of disease outcome thus help us in designing future precision therapies. The evidence indicates that a combination of conventional chemotherapeutic agents and novel drugs designed to target specific dysregulated signaling pathways can provide the effective therapeutic options for both untreated and relapse/refractory MCL.

Post-transplant lymphoproliferative disease after liver transplantation

We have read the article "Post-transplant lymphoproliferative disease in liver transplant recipients" with great interest. This article reports a series of liver transplant recipients with post-transplant lymphoproliferative disease (PTLD). The effect on patient survival and the potential benefit of rituximab-based therapy are highlighted. Rituximab is a chimeric antibody against the CD20 surface marker. This marker is found in most PTLD of a B cell origin. A recent study from our center also highlighted the role of rituximab in PTLD therapy (3). The overall response rate of patients treated with rituximab was 66% in both series. In our series, this included heart, kidney and liver transplant recipients. Rituximab-based therapy was also associated with an increased overall survival. Rituximab should be considered as part of the first-line therapy in patients with PTLD when CD20 expression is present.

Association of rituximab with graphene oxide confers direct cytotoxicity for CD20-positive lymphoma cells

Non-Hodgkin lymphoma (NHL) is one of the most common hematologic malignancies among adults for which the chimeric monoclonal anti-CD20 antibody (Ab) rituximab (RTX) is used as first-line therapy. As RTX itself is not directly cytotoxic but relies on host immune effector mechanisms or chemotherapeutic agents to attack target cells, its therapeutic capacity may become limited when host effector mechanisms are compromised. Currently, refractory disease and relapse with NHL are still common, highlighting the need for novel anti-CD20 antibody strategies with superior therapeutic efficacy over current protocols. We hypothesized that making RTX directly cytotoxic might improve the therapeutic efficacy. Graphene oxide (GO) has recently emerged as a highly attractive nanomaterial for biomedical applications; and several studies have reported cytotoxic effect of GO on benign and malignant cells in vitro. Herein, we report that RTX can be stably associated with GO, and that GO-associated RTX (RTX/GO) demonstrates remarkably high avidity for CD20. Binding of GO-associated RTX to CD20-positive lymphoma cells induces CD20 capping and target cell death through an actin dependent mechanism. In vivo, GO-associated RTX, but not free RTX, quickly eliminates high-grade lymphomas in the absence of host effector mechanisms in a xenograft lymphoma mouse model. Our findings represent the first demonstration of using GO-associated antibody as effective cytotoxic therapy for human B cell malignancies in the absence of chemotherapy, and these findings could have important clinical implications.

Nanoscale imaging and force probing of biomolecular systems using atomic force microscopy: from single molecules to living cells

Due to the lack of adequate tools for observation, native molecular behaviors at the nanoscale have been poorly understood. The advent of atomic force microscopy (AFM) provides an exciting instrument for investigating physiological processes on individual living cells with molecular resolution, which attracts the attention of worldwide researchers. In the past few decades, AFM has been widely utilized to investigate molecular activities on diverse biological interfaces, and the performances and functions of AFM have also been continuously improved, greatly improving our understanding of the behaviors of single molecules in action and demonstrating the important role of AFM in addressing biological issues with unprecedented spatiotemporal resolution. In this article, we review the related techniques and recent progress about applying AFM to characterize biomolecular systems in situ from single molecules to living cells. The challenges and future directions are also discussed.

Antibody-dependent fragmentation is a newly identified mechanism of cell killing in vivo

The prevailing view is that therapeutic antibodies deplete cells through opsonization and subsequent phagocytosis, complement-dependent lysis or antibody-dependent cellular-cytotoxicity. We used high resolution in vivo imaging to identify a new antibody-dependent cell death pathway where Kupffer cells ripped large fragments off crawling antibody-coated iNKT cells. This antibody-dependent fragmentation process resulted in lethality and depletion of crawling iNKT cells in the liver sinusoids and lung capillaries. iNKT cell depletion was Fcy-receptor dependent and required iNKT cell crawling. Blood, spleen or joint iNKT cells that did not crawl were not depleted. The antibody required high glycosylation for sufficiently strong binding of the iNKT cells to the Fc Receptors on Kupffer cells. Using an acetaminophen overdose model, this approach functionally depleted hepatic iNKT cells and affected the severity of liver injury. This study reveals a new mechanism of antibody-dependent killing in vivo and raises implications for the design of new antibodies for cancer and auto-reactive immune cells.

Chronic lymphocytic leukemia: 2017 update on diagnosis, risk stratification, and treatment

DISEASE OVERVIEW

Chronic lymphocytic leukemia (CLL) is the commonest leukemia in western countries. The disease typically occurs in elderly patients and has a highly variable clinical course. Leukemic transformation is initiated by specific genomic alterations that impair apoptosis of clonal B cells.

DIAGNOSIS

The diagnosis is established by blood counts, blood smears, and immunophenotyping of circulating B lymphocytes, which identify a clonal B-cell population carrying the CD5 antigen and B-cell markers.

PROGNOSIS

Two prognostic staging systems exist, the Rai and Binet staging systems, which are established by physical examination and blood counts. Various biological and genetic markers also have prognostic value. Deletions of the short arm of chromosome 17 (del(17p)) and/or mutations of the TP53 gene predict resistance to available chemotherapies. A comprehensive prognostic score (CLL-IPI) using genetic, biological, and clinical variables has recently been developed allowing to classify CLL into very distinct risk groups.

THERAPY

Patients with active or symptomatic disease or with advanced Binet or Rai stages require therapy. For physically fit patients, chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab remains the current standard therapy. For unfit patients, currently available evidence supports two options for a first-line therapy: chlorambucil combined with an anti-CD20 antibody (obinutuzumab or rituximab or ofatumumab) or a continuous therapy with ibrutinib. At relapse, the initial treatment may be repeated, if the treatment-free interval exceeds 3 years. If the disease relapses earlier, therapy should be changed using alternative agents such as bendamustine (plus rituximab), alemtuzumab, lenalidomide, ofatumumab, ibrutinib, idelalisib, or venetoclax. Patients with a del(17p) or TP53 mutation can be treated with ibrutinib, venetoclax, or a combination of idelalisib and rituximab. An allogeneic SCT may be considered in relapsing patients with TP53 mutations or del(17p) or patients that are refractory to chemoimmunotherapy and the novel inhibitors.

FUTURE CHALLENGES

The new agents (ibrutinib, idelalisib, venetoclax, and obinutuzumab) hold the potential to significantly improve the outcome of CLL patients. However, their optimal use (in terms of combination, sequence, and duration) remains unknown. Therefore, CLL patients should be treated in clinical trials whenever possible.

Therapeutic Antibodies to KIR3DL2 and Other Target Antigens on Cutaneous T-Cell Lymphomas

KIR3DL2 is a member of the killer cell immunoglobulin-like receptor (KIR) family that was initially identified at the surface of natural killer (NK) cells. KIR3DL2, also known as CD158k, is expressed as a disulfide-linked homodimer. Each chain is composed of three immunoglobulin-like domains and a long cytoplasmic tail containing two immunoreceptor tyrosine-based inhibitory motifs. Beside its expression on NK cells, it is also found on rare circulating T lymphocytes, mainly CD8⁺. Although the KIR gene number varies between haplotype, KIR3DL2 is a framework gene present in all individuals. Together with the presence of genomic regulatory sequences unique to KIR3DL2, this suggests some particular functions for the derived protein in comparison with other KIR family members. Several ligands have been identified for KIR3DL2. As for other KIRs, binding to HLA class I molecules is essential for NK development by promoting phenomena such as licensing and driving NK cell maturation. For KIR3DL2, this includes binding to HLA-A3 and -A11 and to the free heavy chain form of HLA-B27. In addition, KIR3DL2 binds to CpG oligonucleotides (ODN) and ensures their transport to endosomal toll-like receptor 9 that promotes cell activation. These characteristics have implicated KIR3DL2 in several pathologies: ankylosing spondylitis and cutaneous T-cell lymphomas such as Sézary syndrome, CD30⁺ cutaneous lymphoma, and transformed mycosis fungoides. Consequently, a new generation of humanized monoclonal antibodies (mAbs) directed against KIR3DL2 has been helpful in the diagnosis, follow-up, and treatment of these diseases. In addition, preliminary clinical studies of a novel targeted immunotherapy for cutaneous T-cell lymphomas using the anti-KIR3DL2 mAb IPH4102 are now underway. In this review, we discuss the various aspects of KIR3DL2 on the functions of CD4⁺ T cells and how targeting this receptor helps to develop innovative therapeutic strategies.

Drug-Free Macromolecular Therapeutics Induce Apoptosis via Calcium Influx and Mitochondrial Signaling Pathway

Recently, an innovative paradigm has been proposed in macromolecular therapeutics for treatment of B-cell lymphomas that can specifically kill cancer cells without a drug. The design rationale of this drug-free macromolecular therapeutic (DFMT) system is crosslinking the cell surface receptor to initiate apoptosis. However, how the apoptosis signal is triggered after receptor hyper-crosslinking remains to be elucidated. Here, two pathways, calcium influx dependent pathway and mitochondrial signal pathway, are identified to play major roles in triggering the programmed cell death. With the first step pretargeting and second step multiple binding, receptor hyper-crosslinking is achieved in a highly specific, time-dependent manner and largely mediated by multivalence. As a consequence, extracellular calcium influx is triggered, which subsequently decreases the mitochondrial membrane potential and induces apoptosis. The mitochondrial depolarization also stems from the Bcl-2 inhibition mediated by DFMT, followed by the cytochrome c release that activates caspase signaling. With the participation of the two-pronged mechanism, a programmed apoptosis is induced in response to DFMT treatment. The current findings can offer important implications to optimize the anti-CD20 strategies to treat B-cell non-Hodgkin lymphomas.

Featured Article: Delivery of chemotherapeutic vcMMAE using tobacco mosaic virus nanoparticles

The first-line treatment for non-Hodgkin's lymphoma is chemotherapy. While generally well tolerated, off-target effects and chemotherapy-associated complications are still of concern. To overcome the challenges associated with systemic chemotherapy, we developed a biology-inspired, nanoparticle drug delivery system (nanoDDS) making use of the nucleoprotein components of the tobacco mosaic virus (TMV). Virus-based nanoparticles, including the high-aspect ratio soft nanorods formed by TMV, are growing in popularity as nanoDDS due to their simple genetic and chemical engineerability, size and shape tunability, and biocompatibility. In this study, we used bioconjugation to modify TMV as a multivalent carrier for delivery of the antimitotic drug valine-citrulline monomethyl auristatin E (vcMMAE) targeting non-Hodgkin's lymphoma. We demonstrate successful synthesis of the TMV-vcMMAE; data indicate that the TMV-vcMMAE particles remained structurally sound with all of the 2130 identical TMV coat proteins modified to carry the therapeutic payload vcMMAE. Cell uptake using Karpas 299 cells was confirmed with TMV particles trafficking to the endolysosomal compartment, likely allowing for protease-mediated cleavage of the valine-citrulline linker for the release of the active monomethyl auristatin E component. Indeed, effective cell killing of non-Hodgkin's lymphoma in vitro was demonstrated; TMV-vcMMAE was shown to exhibit an IC50 of ∼250 nM. This study contributes to the development of viral nanoDDS. Impact statement Due to side effects associated with systemic chemotherapy, there is an urgent need for the development of novel drug delivery systems. We focus on the high-aspect ratio nanotubes formed by tobacco mosaic virus (TMV) to deliver antimitotic drugs targeted to non-Hodgkin's lymphoma. Many synthetic and biologic nanocarriers are in the development pipeline; the majority of systems are spherical in shape. This may not be optimal, because high-aspect ratio filaments exhibit enhanced tumor homing, increased target cell interactions and decreased immune cell uptake, and therefore have favorable properties for drug delivery compared to their spherical counterparts. Nevertheless, the synthesis of high-aspect ratio materials at the nanoscale remains challenging; therefore, we turned toward the nucleoprotein components of TMV as a biologic nanodrug delivery system. This work presents groundwork for the development of plant virus-based vehicles for use in cancer treatment.

The Antitumor Activity of IMGN529, a CD37-Targeting Antibody-Drug Conjugate, Is Potentiated by Rituximab in Non-Hodgkin Lymphoma Models

Naratuximab emtansine (IMGN529) is an investigational antibody-drug conjugate consisting of a CD37-targeting antibody conjugated to the maytansine-derived microtuble disruptor, DM1. IMGN529 has shown promising preclinical and clinical activity in non-Hodgkin lymphoma, including diffuse large B-cell lymphoma (DLBCL). Due to the aggressive nature of the disease, DLBCL is often treated with combination therapies to maximize clinical outcomes; therefore, we investigated the potential of combining IMGN529 with both standard-of-care and emerging therapies against multiple oncology-relevant targets and pathways. The strongest enhancement in potency was seen with anti-CD20 antibodies, including rituximab. The combination of IMGN529 and rituximab was more potent than either agent alone, and this combinatorial benefit was associated with increased apoptotic induction and cell death. Additional studies revealed that rituximab treatment increased the internalization and degradation of the CD37-targeting antibody moiety of IMGN529. The combination of IMGN529 and rituximab was highly efficacious in multiple xenograft models, with superior antitumor efficacy seen compared to either agent alone or treatment with R-CHOP therapy. These findings suggest a novel mechanism whereby the potency of IMGN529 can be enhanced by CD20 binding, which results in the increased internalization and degradation of IMGN529 leading to the generation of greater amounts of cytotoxic catabolite. Overall, these data provide a biological rationale for the enhanced activity of IMGN529 in combination with rituximab and support the ongoing clinical evaluation of IMGN529 in combination with rituximab in patients with relapsed and/or refractory DLBCL.

Atomic Force Microscopy in Characterizing Cell Mechanics for Biomedical Applications: A Review

Cell mechanics is a novel label-free biomarker for indicating cell states and pathological changes. The advent of atomic force microscopy (AFM) provides a powerful tool for quantifying the mechanical properties of single living cells in aqueous conditions. The wide use of AFM in characterizing cell mechanics in the past two decades has yielded remarkable novel insights in understanding the development and progression of certain diseases, such as cancer, showing the huge potential of cell mechanics for practical applications in the field of biomedicine. In this paper, we reviewed the utilization of AFM to characterize cell mechanics. First, the principle and method of AFM single-cell mechanical analysis was presented, along with the mechanical responses of cells to representative external stimuli measured by AFM. Next, the unique changes of cell mechanics in two types of physiological processes (stem cell differentiation, cancer metastasis) revealed by AFM were summarized. After that, the molecular mechanisms guiding cell mechanics were analyzed. Finally the challenges and future directions were discussed.

Converting Lymphoma Cells into Potent Antigen-Presenting Cells for Interferon-Induced Tumor Regression

Anti-hCD20 is a therapeutic mAb that is clinically used to treat B-cell lymphoma. Some lymphomas are resistant to anti-hCD20; others relapse after treatment with anti-hCD20. Using a syngeneic immunocompetent mouse model, we observed that targeting lymphoma with interferon-α (IFNα) abolished resistance of B-cell lymphoma to anti-CD20 while limiting interferon (IFN)-associated systemic toxicity in the host. Control of tumors by a fusion of anti-CD20 and IFNα (anti-CD20-IFNα) depended on existing tumor-infiltrating CD8⁺ T cells. Although lymphomas were resistant to IFN-directed killing, IFN-exposed tumor cells became the dominant antigen-presenting cells (APC) for the reactivation of tumor-infiltrating CD8⁺ T cells that then controlled those lymphomas. Anti-CD20-IFNα also abolished checkpoint blockade resistance in advanced B-cell lymphoma. Our findings indicate that anti-CD20-IFNα eradicates B-cell lymphoma by employing tumor cells as APCs to reactivate tumor-infiltrating CD8⁺ T cells and synergizing with anti-PD-L1 treatment. Cancer Immunol Res; 5(7); 560-70. ©2017 AACR.

Dancing partners at the ball: Rational selection of next generation anti-CD20 antibodies for combination therapy of chronic lymphocytic leukemia in the novel agents era

The anti-CD20 antibodies represent a major advancement in the therapeutic options available for chronic lymphocytic leukemia. The addition of rituximab, ofatumumab and obinutuzumab to various chemotherapy regimens has led to considerable improvements in both response and survival. Ocaratuzumab, veltuzumab and ublituximab are currently being explored within the trial setting. We review the current status of these antibodies, and discuss how their mechanisms of action may impact on the choice of combinations with novel small molecule agents.

Genetic and Epigenetic Modulation of CD20 Expression in B-Cell Malignancies: Molecular Mechanisms and Significance to Rituximab Resistance

CD20 is a differentiation related cell surface phosphoprotein that is expressed during early pre-B cell stages until plasma cell differentiation, and is a suitable molecular target for B-cell malignancies by monoclonal antibodies such as rituximab, ofatumumab, obinutuzumab and others. CD20 expression is confirmed in most B-cell malignancies; however, the protein expression level varies in each patient, even in de novo tumors, and down-modulation of CD20 expression after chemoimmunotherapy with rituximab, resulting in rituximab resistance, has been recognized in the clinical setting. Recent reports suggest that genetic and epigenetic mechanisms are correlated with aberrantly low CD20 expression in de novo tumors and relapsed/refractory disease after using rituximab. Furthermore, some targeting drugs, such as lenalidomide, bortezomib and ibrutinib, directly or indirectly affect CD20 protein expression. CD20-negative phenotypically-changed DLBCL after rituximab use tends to show an aggressive clinical course and poor outcome with resistance to not only rituximab, but also conventional salvage chemo-regimens. Understanding of the mechanisms of CD20-negative phenotype may contribute to establish strategies for overcoming chemo-refractory B-cell malignancies. In this manuscript, recent progress of research on molecular and clinical features of CD20 protein and CD20-negative B-cell malignancies was reviewed.

Autoimmune epilepsy

Seizures are a common manifestation of autoimmune limbic encephalitis and multifocal paraneoplastic disorders. Accumulating evidence supports an autoimmune basis for seizures in the absence of syndromic manifestations of encephalitis. The autoimmune epilepsies are immunologically mediated disorders in which recurrent seizures are a primary and persistent clinical feature. When other etiologies have been excluded, an autoimmune etiology is suggested in a patient with epilepsy upon detection of neural autoantibodies and/or the presence of inflammatory changes on cerebrospinal fluid (CSF) or magnetic resonance imaging. In such patients, immunotherapy may be highly effective, depending on the particular autoimmune epilepsy syndrome present. In this chapter, several autoimmune epilepsy syndromes are discussed. First, epilepsies secondary to other primary autoimmune disorders will be discussed, and then those associated with antibodies that are likely to be pathogenic, such as voltage-gated potassium channel-complex and N-methyl-d-aspartate receptor, gamma-aminobutyric acid A and B receptor antibodies. For each syndrome, the typical clinical, imaging, electroencephaloram, CSF, and serologic features, and pathophysiology and treatment are described. Finally, suggested guidelines for the recognition, evaluation, and treatment of autoimmune epilepsy syndromes are provided.