Immunotherapy for Multiple Myeloma. Cancers (Basel). 2019;11:2009. [PMID: 31842518 PMCID: PMC6966649 DOI: 10.3390/cancers11122009]

PD-1 and LAG-3-positive T cells are associated with clinical outcomes of relapsed/refractory multiple myeloma patients

OBJECTIVE

To investigate the frequency of PD-1 and LAG-3-positive T cells in relapsed/refractory multiple myeloma (RRMM) patients and its clinical significance.

METHODS

This prospective observational study enrolled a total of 71 RRMM patients, as well as 70 MM patients (non-refractory) and 70 healthy individuals during January 2018 to March 2021. The frequency of circulating CD4⁺ and CD8⁺ T cells expressing PD-1 and LAG-3 was analyzed using flow cytometry. Serum cytokines of IL-6, IL-17, CRP, TNF-α and TGF-β were evaluated by enzyme linked immunosorbent assay (ELISA).

RESULTS

Significant higher 1-year mortality rate was found in RRMM patients compared with the MM patients. In both CD4⁺ and CD8⁺ T cells, the frequencies of PD-1⁺, LAG-3⁺ and PD-1⁺/LAG-3⁺ T cells were markedly higher in the RRMM patients and the deceased patients, compared with the MM patients and the survival patients, respectively. All cytokines were remarkably higher in RRMM and MM patients than in the healthy control, while only serum levels of IL-6 and IL-17 were markedly higher in RRMM patients compared with the MM patients. Positive correlation was observed among the IL-6, IL-17 and the frequencies of circulating T cells in both CD4⁺ and CD8⁺ T cells in RRMM and MM patients. The frequency of CD8⁺PD-1⁺LAG-3⁺ T cells showed the best sensitivity 82.61% and specificity 76.06% for diagnosis of RRMM using ROC curve. Meanwhile, the frequency of CD4⁺PD-1⁺ cells showed the best sensitivity 84.00% and specificity 97.35% for prediction of patients' mortality by ROC curve. The frequencies of CD4⁺PD-1⁺, CD8⁺PD-1⁺/LAG-3⁺, as well as IL-6, IL-17 and TNF-α were found as risk factors for incidence of RRMM in all MM patients.

CONCLUSION

The frequency of PD-1 and LAG-3-positive T cells is associated with the clinical severity and inflammation in RRMM patients, which may also serve as potential biomarkers for its diagnosis.

Pomalidomide enhances the maturation of dendritic cells derived from healthy donors and multiple myeloma patients

Objective: To explore the effect of pomalidomide on the maturation of monocyte-derived dendritic cells (moDCs) from healthy donors (HDs) and multiple myeloma (MM) patients. Methods: MoDCs were generated by the incubation of monocytes from peripheral blood mononuclear cells (PBMCs) for 7 days in a medium consisting of 800 U/ml granulocyte-macrophage colony stimulating factor (GM-CSF), 500 U/ml interleukin-4 (IL-4), RPMI 1,640 medium, 5% human serum, 100 U/ml penicillin and 0.1 mg/ml streptomycin. Meanwhile, the incubation system was administrated with 10 µM pomalidomide or 1 × PBS as the control group. On the eighth day, cells were harvested and analyzed by flow cytometry. The CD80⁺CD86⁺ cell population in total cells was gated as moDCs in the FACS analyzing system. After that, the expression of CD40 and HLA-DR on moDCs was analyzed. Meanwhile, the supernatant from the incubation system was evaluated for the secretion of cytokines interleukin-12 (IL-12), tumor necrosis factor-α (TNF-α), and macrophage inflammatory protein 1α (MIP-1α) by enzyme-linked immunosorbent assay (ELISA). Results: When analyzing all the HD-moDCs together (n = 15), pomalidomide significantly increased the mean fluorescence intensity (MFI) of CD40 expression and HLA-DR expression on moDCs compared with the control group (p = 0.003, p = 0.040). Meanwhile, the proportion of CD40⁺ moDCs and HLA-DR⁺ moDCs in total moDCs was significantly higher in the pomalidomide group than in the control group (p = 0.008, p = 0.032). When analyzing all MM patient-moDCs together (n = 11), pomalidomide significantly increased the MFI of CD40 expression and HLA-DR expression on moDCs compared with the control group (p = 0.047, p = 0.006). Meanwhile, the proportion of HLA-DR⁺ moDCs in total DCs was significantly higher in the pomalidomide group than in the control group (p < 0.001). Moreover, HD-moDCs (n = 8) treated with pomalidomide secreted 192% IL-12, 110% TNF-α, and 112% MIP-1α of the untreated moDCs (p = 0.020, p = 0.006, p = 0.055). However, when analyzing MM patient-moDCs (n = 10) together, the secretion of IL-12, TNF-α and MIP-1α from moDCs showed no significant difference between the pomalidomide group and the control group (p = 0.458, p = 0.377, p = 0.248). Conclusion: In vitro, 10 µM pomalidomide enhances the maturation of moDCs derived from both HDs and MM patients. Pomalidomide shows potential to be applied as a DC adjuvant for DC-based immunotherapy, such as the DC vaccine and DC cell therapy in MM.

Genome Instability in Multiple Myeloma: Facts and Factors

Multiple myeloma (MM) is a malignant neoplasm of terminally differentiated immunoglobulin-producing B lymphocytes called plasma cells. MM is the second most common hematologic malignancy, and it poses a heavy economic and social burden because it remains incurable and confers a profound disability to patients. Despite current progress in MM treatment, the disease invariably recurs, even after the transplantation of autologous hematopoietic stem cells (ASCT). Biological processes leading to a pathological myeloma clone and the mechanisms of further evolution of the disease are far from complete understanding. Genetically, MM is a complex disease that demonstrates a high level of heterogeneity. Myeloma genomes carry numerous genetic changes, including structural genome variations and chromosomal gains and losses, and these changes occur in combinations with point mutations affecting various cellular pathways, including genome maintenance. MM genome instability in its extreme is manifested in mutation kataegis and complex genomic rearrangements: chromothripsis, templated insertions, and chromoplexy. Chemotherapeutic agents used to treat MM add another level of complexity because many of them exacerbate genome instability. Genome abnormalities are driver events and deciphering their mechanisms will help understand the causes of MM and play a pivotal role in developing new therapies.

Identification of three immune molecular subtypes associated with immune profiles, immune checkpoints, and clinical outcome in multiple myeloma

Purpose

To identify the immune molecular subtype for MM to help achieve individualized and precise targeted therapy.

Methods

The GDC API was used to download the TCGA‐MM profile dataset, which contains 859 samples in total, all of which were anterior to the standard treatment after diagnosis. Moreover, 282, 298, and 258 samples were stage I, stage II, and stage III separately. We used the immune gene expression profile for consistent clustering; and used the R software package ConsensusClusterPlus to sort the immune molecular subtypes. Correlation between subtypes and clinical features, immunity, and prognosis was then analyzed.

Results

A total of 859 tumor samples were separated into these three subtypes, which were not meaningfully related to age or sex but showed a remarkable association with stage. The results suggested that obvious differences in immune metagene expression and expression of 10 immune checkpoint genes appeared among the three subtypes.

Conclusion

The three subtypes are distinctly different in terms of immune metagenes, immune checkpoint molecules, and clinical prognosis. The discovery of the immune microenvironment of MM could further reveal the strategy for immunotherapy in MM and provide a promising candidate prognostic tool for survival.

Overcoming the Immunosuppressive Tumor Microenvironment in Multiple Myeloma

Simple Summary

This article provides a comprehensive review of new and emerging treatment strategies against multiple myeloma that employ precision medicines and/or drugs capable of improving the ability of the immune system to prevent or slow down the progression of multiple myeloma. These rationally designed new treatment methods have the potential to change the therapeutic landscape in multiple myeloma and improve the long-term survival outcome.

Abstract

SeverFigurel cellular elements of the bone marrow (BM) microenvironment in multiple myeloma (MM) patients contribute to the immune evasion, proliferation, and drug resistance of MM cells, including myeloid-derived suppressor cells (MDSCs), tumor-associated M2-like, “alternatively activated” macrophages, CD38+ regulatory B-cells (Bregs), and regulatory T-cells (Tregs). These immunosuppressive elements in bidirectional and multi-directional crosstalk with each other inhibit both memory and cytotoxic effector T-cell populations as well as natural killer (NK) cells. Immunomodulatory imide drugs (IMiDs), protease inhibitors (PI), monoclonal antibodies (MoAb), adoptive T-cell/NK cell therapy, and inhibitors of anti-apoptotic signaling pathways have emerged as promising therapeutic platforms that can be employed in various combinations as part of a rationally designed immunomodulatory strategy against an immunosuppressive tumor microenvironment (TME) in MM. These platforms provide the foundation for a new therapeutic paradigm for achieving improved survival of high-risk newly diagnosed as well as relapsed/refractory MM patients. Here we review the scientific rationale and clinical proof of concept for each of these platforms.

Immune Functions of Signaling Lymphocytic Activation Molecule Family Molecules in Multiple Myeloma

Simple Summary

Multiple myeloma (MM) is an incurable hematological malignancy characterized by an increase in abnormal plasma cells. Disease progression, drug resistance, and immunosuppression in MM are associated with immune-related molecules, such as immune checkpoint and co-stimulatory molecules, present in the tumor microenvironment. Novel agents targeting these cell-surface molecules are currently under development, including monoclonal antibodies, bispecific monoclonal antibodies, and chimera antigen receptor T-cell therapies. In this review, we focus on the signaling lymphocytic activation molecule family receptors and provide an overview of their biological functions and novel therapies in MM.

Abstract

The signaling lymphocytic activation molecule (SLAM) family receptors are expressed on various immune cells and malignant plasma cells in multiple myeloma (MM) patients. In immune cells, most SLAM family molecules bind to themselves to transmit co-stimulatory signals through the recruiting adaptor proteins SLAM-associated protein (SAP) or Ewing’s sarcoma-associated transcript 2 (EAT-2), which target immunoreceptor tyrosine-based switch motifs in the cytoplasmic regions of the receptors. Notably, SLAMF2, SLAMF3, SLAMF6, and SLAMF7 are strongly and constitutively expressed on MM cells that do not express the adaptor proteins SAP and EAT-2. This review summarizes recent studies on the expression and biological functions of SLAM family receptors during the malignant progression of MM and the resulting preclinical and clinical research involving four SLAM family receptors. A better understanding of the relationship between SLAM family receptors and MM disease progression may lead to the development of novel immunotherapies for relapse prevention.

Why Immunotherapy Fails in Multiple Myeloma

Multiple myeloma remains an incurable disease despite great advances in its therapeutic landscape. Increasing evidence supports the belief that immune dysfunction plays an important role in the disease pathogenesis, progression, and drug resistance. Recent efforts have focused on harnessing the immune system to exert anti-myeloma effects with encouraging outcomes. First-in-class anti-CD38 monoclonal antibody, daratumumab, now forms part of standard treatment regimens in relapsed and refractory settings and is shifting to front-line treatments. However, a non-negligible number of patients will progress and be triple refractory from the first line of treatment. Antibody-drug conjugates, bispecific antibodies, and chimeric antigen receptors (CAR) are being developed in a heavily pretreated setting with outstanding results. Belantamab mafodotin-blmf has already received approval and other anti-B-cell maturation antigen (BCMA) therapies (CARs and bispecific antibodies are expected to be integrated in therapeutic options against myeloma soon. Nonetheless, immunotherapy faces different challenges in terms of efficacy and safety, and manufacturing and economic drawbacks associated with such a line of therapy pose additional obstacles to broadening its use. In this review, we described the most important clinical data on immunotherapeutic agents, delineated the limitations that lie in immunotherapy, and provided potential insights to overcome such issues.

Treatment of Multiple Myeloma Using Chimeric Antigen Receptor T Cells with Dual Specificity

Chimeric antigen receptor (CAR) T-cell therapy has shown remarkable successes in fighting B-cell leukemias/lymphomas. Promising response rates are reported in patients treated with B-cell maturation antigen (BCMA) CAR T cells for multiple myeloma. However, responses appear to be nondurable, highlighting the need to expand the repertoire of multiple myeloma-specific targets for immunotherapy and to generate new CAR T cells. Here, we developed a "dual-CAR" targeting two multiple myeloma-associated antigens and explored its safety and efficacy. To reduce the "off-target" toxicity, we used the recognition of paired antigens that were coexpressed by the tumor to induce efficient CAR T-cell activation. The dual-CAR construct presented here was carefully designed to target the multiple myeloma-associated antigens, taking into consideration the distribution of both antigens on normal human tissues. Our results showed that the CD138/CD38-targeted dual CAR (dCAR138-38) elicited a potent anti-multiple myeloma response both in vitro and in vivo NSG mice transplanted with a multiple myeloma cell line and treated with dCAR138-38 showed median survival of 97 days compared with 31 days in the control group treated with mock-lymphocytes. The dCAR138-38 showed increased specificity toward cells expressing both targeted antigens compared with single-antigen-expressing cells and low activity toward primary cells from healthy tissues. Our findings indicated that the dCAR138-38 may provide a potent and safe alternative therapy for patients with multiple myeloma.

Hunting down the dominating subclone of cancer stem cells as a potential new therapeutic target in multiple myeloma: An artificial intelligence perspective

The development of single-cell subclones, which can rapidly switch from dormant to dominant subclones, occur in the natural pathophysiology of multiple myeloma (MM) but is often "pressed" by the standard treatment of MM. These emerging subclones present a challenge, providing reservoirs for chemoresistant mutations. Technological advancement is required to track MM subclonal changes, as understanding MM's mechanism of evolution at the cellular level can prompt the development of new targeted ways of treating this disease. Current methods to study the evolution of subclones in MM rely on technologies capable of phenotypically and genotypically characterizing plasma cells, which include immunohistochemistry, flow cytometry, or cytogenetics. Still, all of these technologies may be limited by the sensitivity for picking up rare events. In contrast, more incisive methods such as RNA sequencing, comparative genomic hybridization, or whole-genome sequencing are not yet commonly used in clinical practice. Here we introduce the epidemiological diagnosis and prognosis of MM and review current methods for evaluating MM subclone evolution, such as minimal residual disease/multiparametric flow cytometry/next-generation sequencing, and their respective advantages and disadvantages. In addition, we propose our new single-cell method of evaluation to understand MM's mechanism of evolution at the molecular and cellular level and to prompt the development of new targeted ways of treating this disease, which has a broad prospect.

Engineering the Bridge between Innate and Adaptive Immunity for Cancer Immunotherapy: Focus on γδ T and NK Cells

Most studies on genetic engineering technologies for cancer immunotherapy based on allogeneic donors have focused on adaptive immunity. However, the main limitation of such approaches is that they can lead to severe graft-versus-host disease (GvHD). An alternative approach would bolster innate immunity by relying on the natural tropism of some subsets of the innate immune system, such as γδ T and natural killer (NK) cells, for the tumor microenvironment and their ability to kill in a major histocompatibility complex (MHC)-independent manner. γδ T and NK cells have the unique ability to bridge innate and adaptive immunity while responding to a broad range of tumors. Considering these properties, γδ T and NK cells represent ideal sources for developing allogeneic cell therapies. Recently, significant efforts have been made to exploit the intrinsic anti-tumor capacity of these cells for treating hematologic and solid malignancies using genetic engineering approaches such as chimeric antigen receptor (CAR) and T cell receptor (TCR). Here, we review over 30 studies on these two approaches that use γδ T and NK cells in adoptive cell therapy (ACT) for treating cancer. Based on those studies, we propose several promising strategies to optimize the clinical translation of these approaches.

Maintenance Strategies Post-Autologous Stem Cell Transplantation for Newly Diagnosed Multiple Myeloma

Multiple myeloma, the second most common hematological malignancy worldwide, has demonstrated dramatic improvements in outcome in the last decade. In newly diagnosed patients, induction chemotherapy followed by autologous stem cell transplantation (ASCT) is the standard of care. After ASCT, the majority of patients experience disease remission but, despite recent therapeutic developments, most will eventually relapse. In this review we consider clinical aspects of maintenance therapies that can be used post-ASCT to prolong remission duration. We discuss the evidence for the effectiveness of each of these drugs as a maintenance therapy, alongside other benefits and drawbacks to their use, for example, route of administration and potential toxicities. We discuss questions which remain unanswered around the optimal use of currently available maintenance therapies and review newer agents being considered for use as maintenance such as emerging immunotherapies.

PD-L1-PD-1 Pathway in the Pathophysiology of Multiple Myeloma

PD-L1 expressed on tumor cells contributes to disease progression with evasion from tumor immunity. Plasma cells from multiple myeloma (MM) patients expressed higher levels of PD-L1 compared with healthy volunteers and monoclonal gammopathy of undetermined significance (MGUS) patients, and its expression is significantly upregulated in relapsed/refractory patients. Furthermore, high PD-L1 expression is induced by the myeloma microenvironment and PD-L1+ patients with MGUS and asymptomatic MM tend to show disease progression. PD-L1 expression on myeloma cells was associated with more proliferative potential and resistance to antimyeloma agents because of activation of the Akt pathway through PD-1-bound PD-L1 in MM cells. Those data suggest that PD-L1 plays a crucial role in the disease progression of MM.