Targeting CD79b for Chimeric Antigen Receptor T-Cell Therapy of B-Cell Lymphomas

POU Class 2 Homeobox Associating Factor 1, as a Hub Candidate Gene in OP, Relieves Osteoblast Apoptosis

Increasing evidence suggests that osteoblast apoptosis contributes to the pathogenesis of postmenopausal osteoporosis (PMOP). This study aimed to identify a hub gene associated with osteoporosis (OP) progression and its functions. We utilized the GSE68303 expression dataset from GEO database and conducted weighted gene co-expression network analysis (WGCNA) to investigate changes in co-expressed genes between sham and ovariectomy (OVX) groups. Differentially expressed genes (DEGs) were identified using the "limma" R package on GSE68303 dataset. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the DAVID database. A protein-protein interaction (PPI) network was constructed using the STRING database, which was visualized by Cytoscape software. The top ten hub genes were screened using the Cytohubba plugin, among which POU class 2 homeobox associating factor 1 (POU2AF1), an OP-related hub gene, showed a significant increase in OVX-induced mouse model based on immunohistochemical staining. Inhibition of POU2AF1 suppressed cell viability, induced cell cycle arrest at the G1 phase, and promoted osteoblast apoptosis as demonstrated by CCK-8 assay, flow cytometry analysis, and TUNEL assay. Moreover, overexpression of POU2AF1 decreased cleaved caspase-3/-8/-9 expression while increasing cyclinD1 and Ki67 expression in MC3T3-E1 and hFOB1.19 cells. Therefore, POU2AF1 may serve as a potential diagnostic biomarker for slowing down the progression of OP.

Chimeric antigen receptor T cells to target CD79b in B-cell lymphomas

BACKGROUND

Chimeric antigen receptor (CAR) T cells targeting CD19 mediate potent and durable effects in B-cell malignancies. However, antigen loss or downregulation is a frequent cause of resistance. Here, we report development of a novel CAR T-cell therapy product to target CD79b, a pan B-cell antigen, widely expressed in most B-cell lymphomas.

METHODS

We generated a novel anti-CD79b monoclonal antibody by hybridoma method. The specificity of the antibody was determined by testing against isogenic cell lines with human CD79b knock-in or knock-out. A single-chain variable fragment derived from the monoclonal antibody was used to make a panel of CD79b-targeting CAR molecules containing various hinge, transmembrane, and co-stimulatory domains. These were lentivirally transduced into primary T cells and tested for antitumor activity in in vitro and in vivo B-cell lymphoma models.

RESULTS

We found that the novel anti-CD79b monoclonal antibody was highly specific and bound only to human CD79b and no other cell surface protein. In testing the various CD79b-targeting CAR molecules, superior antitumor efficacy in vitro and in vivo was found for a CAR consisting CD8α hinge and transmembrane domains, an OX40 co-stimulatory domain, and a CD3ζ signaling domain. This CD79b CAR specifically recognized human CD79b-expressing lymphoma cell lines but not CD79b knock-out cell lines. CD79b CAR T cells, generated from T cells from either healthy donors or patients with lymphoma, proliferated, produced cytokines, degranulated, and exhibited robust cytotoxic activity in vitro against CD19+ and CD19- lymphoma cell lines and patient-derived lymphoma tumors relapsing after prior CD19 CAR T-cell therapy. Furthermore, CD79b CAR T cells were highly efficient at eradicating pre-established lymphoma tumors in vivo in three aggressive lymphoma xenograft models, including two cell line-derived xenografts and one patient-derived xenograft. Notably, these CAR T cells did not demonstrate any significant tonic signaling activity or markers of exhaustion.

CONCLUSION

Our results indicated that this novel CD79b CAR T-cell therapy product has robust antitumor activity against B-cell lymphomas. These results supported initiation of a phase 1 clinical trial to evaluate this product in patients with relapsed or refractory B-cell lymphomas.

The future of CAR T-cell therapy for B-cell acute lymphoblastic leukemia in pediatrics and adolescents

INTRODUCTION

Antigen down-regulation and early chimeric antigen receptor (CAR) T cell loss have emerged as 2 major challenges threatening outcomes following CD19-specific CAR T cell therapy for children and young adults with B-cell acute lymphoblastic leukemia (B-ALL). In addressing the future of CAR T cell therapy for B-ALL, innovative strategies to avert antigen downregulation and enhance CAR persistence warrant prioritized focus.

AREAS COVERED

We describe promising engineering strategies to refine CAR constructs to reverse exhaustion, develop regulatable CARs, optimize manufacturing, enrich for immune memory and disrupt immune inhibition. We additionally focus on alternative targeting to CD19-monospecific targeting and contextualize possibilities for expanded CAR utilization.

EXPERT OPINION

We describe research advances as they are independently reported, however anticipate an integrative strategy incorporating complementary modifications will be required to effectively address CAR loss, overcome antigen downregulation and enhance reliability and durability of CAR T cell responses for B-ALL.

Multi-targeted immunotherapeutics to treat B cell malignancies

The concept of multi-targeted immunotherapeutic systems has propelled the field of cancer immunotherapy into an exciting new era. Multi-effector molecules can be designed to engage with, and alter, the patient's immune system in a plethora of ways. The outcomes can vary from effector cell recruitment and activation upon recognition of a cancer cell, to a multipronged immune checkpoint blockade strategy disallowing evasion of the cancer cells by immune cells, or to direct cancer cell death upon engaging multiple cell surface receptors simultaneously. Here, we review the field of multi-specific immunotherapeutics implemented to treat B cell malignancies. The mechanistically diverse strategies are outlined and discussed; common B cell receptor antigen targeting strategies are outlined and summarized; and the challenges of the field are presented along with optimistic insights for the future.

Efficient chimeric antigen receptor (CAR) targeting of a central epitope of CD22

Chimeric antigen receptor (CAR) T cell therapy has had considerable success in the treatment of B cell malignancies. Targeting the B-lineage markerCD19 has brought great advances to treatment of acute lymphoblastic leukemia (ALL) and B cell lymphomas. However, relapse remains an issue in many cases. Such relapse can result from downregulation or loss of CD19 from the malignant cell population, or expression of alternate isoforms. Consequently, there remains a need to target alternative B-cell antigens and diversify the spectrum of epitopes targeted within the same antigen. CD22 has been identified as a substitute target in cases of CD19-negative relapse. One anti-CD22 antibody - clone m971 - targets a membrane-proximal epitope of CD22 and has been widely validated and used in the clinic. Here we have compared m971-CAR with a novel CAR derived from IS7, an antibody that targets a central epitope on CD22. The IS7-CAR has superior avidity, and is active and specific against CD22 positive targets, including B-ALL patient-derived xenograft (PDX) samples. Side-by-side comparisons indicated that while IS7-CAR killed less rapidly than m971-CAR in vitro, it remains efficient in controlling lymphoma xenograft models in vivo. Thus, IS7-CAR presents a potential alternative candidate for treatment of refractory B-cell malignancies.

Single-Cell Discovery and Multiomic Characterization of Therapeutic Targets in Multiple Myeloma

Multiple myeloma (MM) is a highly refractory hematologic cancer. Targeted immunotherapy has shown promise in MM but remains hindered by the challenge of identifying specific yet broadly representative tumor markers. We analyzed 53 bone marrow (BM) aspirates from 41 MM patients using an unbiased, high-throughput pipeline for therapeutic target discovery via single-cell transcriptomic profiling, yielding 38 MM marker genes encoding cell-surface proteins and 15 encoding intracellular proteins. Of these, 20 candidate genes were highlighted that are not yet under clinical study, 11 of which were previously uncharacterized as therapeutic targets. The findings were cross-validated using bulk RNA sequencing, flow cytometry, and proteomic mass spectrometry of MM cell lines and patient BM, demonstrating high overall concordance across data types. Independent discovery using bulk RNA sequencing reiterated top candidates, further affirming the ability of single-cell transcriptomics to accurately capture marker expression despite limitations in sample size or sequencing depth. Target dynamics and heterogeneity were further examined using both transcriptomic and immuno-imaging methods. In summary, this study presents a robust and broadly applicable strategy for identifying tumor markers to better inform the development of targeted cancer therapy.

SIGNIFICANCE

Single-cell transcriptomic profiling and multiomic cross-validation to uncover therapeutic targets identifies 38 myeloma marker genes, including 11 transcribing surface proteins with previously uncharacterized potential for targeted antitumor therapy.

Evidence-based review of genomic aberrations in diffuse large B cell lymphoma, not otherwise specified (DLBCL, NOS): Report from the cancer genomics consortium lymphoma working group

Diffuse large B cell lymphoma, not otherwise specified (DLBCL, NOS) is the most common type of non-Hodgkin lymphoma (NHL). The 2016 World Health Organization (WHO) classification defined DLBCL, NOS and its subtypes based on clinical findings, morphology, immunophenotype, and genetics. However, even within the WHO subtypes, it is clear that additional clinical and genetic heterogeneity exists. Significant efforts have been focused on utilizing advanced genomic technologies to further subclassify DLBCL, NOS into clinically relevant subtypes. These efforts have led to the implementation of novel algorithms to support optimal risk-oriented therapy and improvement in the overall survival of DLBCL patients. We gathered an international group of experts to review the current literature on DLBCL, NOS, with respect to genomic aberrations and the role they may play in the diagnosis, prognosis and therapeutic decisions. We comprehensively surveyed clinical laboratory directors/professionals about their genetic testing practices for DLBCL, NOS. The survey results indicated that a variety of diagnostic approaches were being utilized and that there was an overwhelming interest in further standardization of routine genetic testing along with the incorporation of new genetic testing modalities to help guide a precision medicine approach. Additionally, we present a comprehensive literature summary on the most clinically relevant genomic aberrations in DLBCL, NOS. Based upon the survey results and literature review, we propose a standardized, tiered testing approach which will help laboratories optimize genomic testing in order to provide the maximum information to guide patient care.

Engineering T-cells with chimeric antigen receptors to combat hematological cancers: an update on clinical trials

Chimeric antigen receptor (CAR) redirected T-cells has shown efficacy in the treatment of B-cell leukemia/lymphoma, however, high numbers of relapses occur due to loss of targeted antigen or intrinsic failure of the CAR T-cells. In this situation modifications of the basic strategy are envisaged to reduce the risk of relapse, some of them are in early clinical exploration. These include simultaneous targeting of multiple antigens or combination of CAR T-cell therapy with other treatment modalities such as checkpoint inhibitors. The review evaluates and discusses these modified advanced therapies and pre-clinical approaches with respect to their potential to control leukemia and lymphoma in the long-term.

The third-generation anti-CD30 CAR T-cells specifically homing to the tumor and mediating powerful antitumor activity

CAR T-cell therapy is well tolerated and effective in patients with Hodgkin lymphoma (HL) and anaplastic large cell lymphoma (ALCL). However, even second- generation anti-CD30 CAR T-cells with CD28 (28z) costimulatory domains failed to achieve the desired rate of complete responses. In the present study, we developed second-generation (CD28z) and third-generation (CD28BBz) CAR T-cells targeting CD30 and investigated their efficacy in vitro and in vivo. Both of CD28z and CD28BBz anti-CD30 CAR T cells were similar regarding amplification, T cell subsets distribution, T cell activity, effector/memory and exhaustion. However, we found that the 28BBz anti-CD30 CAR T-cells persist long-term, specifically homing to the tumor and mediating powerful antitumor activity in tumor xenograft models. Subsequently, we also demonstrated that the third generation anti-CD30 CAR T-cells have miner side effects or potential risks of tumorigenesis. Thus, anti-CD30 CAR T-cells represent a safe and effective treatment for Hodgkin lymphoma.

Development of CAR T Cell Therapy in Children-A Comprehensive Overview

CAR T cell therapy has revolutionized immunotherapy in the last decade with the successful establishment of chimeric antigen receptor (CAR)-expressing cellular therapies as an alternative treatment in relapsed and refractory CD19-positive leukemias and lymphomas. There are fundamental reasons why CAR T cell therapy has been approved by the Food and Drug administration and the European Medicines Agency for pediatric and young adult patients first. Commonly, novel therapies are developed for adult patients and then adapted for pediatric use, due to regulatory and commercial reasons. Both strategic and biological factors have supported the success of CAR T cell therapy in children. Since there is an urgent need for more potent and specific therapies in childhood malignancies, efforts should also include the development of CAR therapeutics and expand applicability by introducing new technologies. Basic aspects, the evolution and the drawbacks of childhood CAR T cell therapy are discussed as along with the latest clinically relevant information.

Advances in chimeric antigen receptor T-cell therapy for B-cell non-Hodgkin lymphoma

B-cell non-Hodgkin lymphoma (B-NHL) is a group of heterogeneous disease which remains incurable despite developments of standard chemotherapy regimens and new therapeutic agents in decades. Some individuals could have promising response to standard therapy while others are unresponsive to standard chemotherapy or relapse after autologous hematopoietic stem-cell transplantation (ASCT), which indicates the necessity to develop novel therapies for refractory or relapsed B-NHLs. In recent years, a novel cell therapy, chimeric antigen receptor T-cell therapy (CAR-T), was invented to overcome the limitation of traditional treatments. Patients with aggressive B-NHL are considered for CAR-T cell therapy when they have progressive lymphoma after second-line chemotherapy, relapse after ASCT, or require a third-line therapy. Clinical trials of anti-CD19 CAR-T cell therapy have manifested encouraging efficacy in refractory or relapsed B-NHL. However, adverse effects of this cellular therapy including cytokine release syndrome, neurotoxicity, tumor lysis syndrome and on-target, off-tumor toxicities should attract our enough attention despite the great anti-tumor effects of CAR-T cell therapy. Although CAR-T cell therapy has shown remarkable results in patients with B-NHL, the outcomes of patients with B-NHL were inferior to patients with acute lymphoblastic leukemia. The inferior response rate may be associated with physical barrier of lymphoma, tumor microenvironment and low quality of CAR-T cells manufactured from B-NHL patients. Besides, some patients relapsed after anti-CD19 CAR-T cell therapy, which possibly were due to limited CAR-T cells persistence, CD19 antigen escape or antigen down-regulation. Quite a few new antigen-targeted CAR-T products and new-generation CAR-T, for example, CD20-targeted CAR-T, CD79b-targeted CAR-T, CD37-targeted CAR-T, multi-antigen-targeted CAR-T, armored CAR-T and four-generation CAR-T are developing rapidly to figure out these deficiencies.

A Review of Chimeric Antigen Receptor T-Cell Therapy for Myeloma and Lymphoma

Collectively, hematological malignancies account for the fourth most common malignancy. Myeloma and lymphoma are the most common types of hematological malignancies. Unfortunately, the management of refractory myeloma and lymphoma remains challenging. The discovery of new immunological therapies, namely chimeric antigen receptors T cells (CAR-T), outlined unprecedented B cell malignancies results. In this context, the CAR-T-based approach has led to the proliferation of many clinical studies. In this review, we will deal with the CAR-T structure, and we will summarize the primary clinical studies assessing the risks and benefits of CAR-T cell therapy. We will also deal with the adverse events and management of cytokine release syndromes/immune effector cell-associated neurotoxicity syndrome (ICANS). Subsequently, we will review potential future improvements to overcome refractoriness and improve expansion while decreasing CAR-T's off-target effects. The advances in the CAR-T platform represent a step forward with promising unlimited future possibilities that made it a paradigm-shifting for the management of B cell malignancies.

CAR-T TREK through the lymphoma universe, to boldly go where no other therapy has gone before

Chimeric antigen receptor (CAR) T cells (CART) therapies have changed and continue to change the treatment paradigms for B-cell malignancies because they can achieve durable complete remission in patients in whom multiple lines of treatment have failed. These unprecedented results have led to the widespread use of anti-CD19 CART therapy for patients with relapsed and refractory aggressive large B-cell lymphomas. While long-term follow-up data show that about one-third of patients achieve prolonged complete remission and are potentially cured, the majority of patients either do not respond to CD19 CART therapy or eventually relapse after CD19 CART therapy. These results are, on the one hand, driving intense research into identifying mechanisms of relapse and, on the other hand, inspiring the development of novel strategies to overcome resistance. This review summarizes current clinical outcomes of CART immunotherapy in B-cell non-Hodgkin lymphomas, describes the most up-to-date understanding of mechanisms of relapse and discusses novel strategies to address resistance to CART therapy. We are indeed at the beginning of a scientific trek to explore the mechanisms of resistance, seek out new, more effective treatment approaches based on these discoveries and to boldly go where no other therapy has gone before!