Over the past 4 decades, basic research has provided crucial information regarding the cellular and molecular biology of cancer. In particular, the relevance of cancer microenvironment (including ...both cellular and noncellular elements) and the concept of clonal evolution and heterogeneity have emerged as important in cancer pathogenesis, immunologic escape, and resistance to therapy. Multiple myeloma (MM), a cancer of terminally differentiated plasma cells, is emblematic of the impact of cancer microenvironment and the role of clonal evolution. Although genetic and epigenetic aberrations occur in MM and evolve over time under the pressure of exogenous stimuli, they are also largely present in premalignant plasma cell dyscrasia such as monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM), suggesting that genetic mutations alone are necessary, but not sufficient, for myeloma transformation. The role of bone marrow microenvironment in mediating survival, proliferation, and resistance to therapy in myeloma is well established; and although an appealing speculation, its role in fostering the evolution of MGUS or SMM into MM is yet to be proven. In this review, we discuss MM pathogenesis with a particular emphasis on the role of bone marrow microenvironment.
We study CD38 levels in immunosuppressive CD4
CD25
Foxp3
regulatory T cells (Treg) and further define immunomodulating effects of a therapeutic CD38 mAb isatuximab/SAR650984 in multiple myeloma.
We ...evaluated percentages of CD38-expressing subsets in Tregs from normal donors and multiple myeloma patients. Peripheral blood mononuclear cells (PBMC) were then treated with isatuximab with or without lenalidomide or pomalidomide to identify their impact on the percentage and immunosuppressive activity of Tregs on CD4
CD25
T cells (Tcons). We investigated the mechanism of increased Tregs in multiple myeloma patients in
cocultures of multiple myeloma cells with PBMCs or Tcons.
CD38 expression is higher on Tregs than Tcons from multiple myeloma patients versus normal donors. CD38 levels and the percentages of CD38
Tregs are increased by lenalidomide and pomalidomide. Isatuximab preferentially decreases Treg and increases Tcon frequencies, which is enhanced by pomalidomide/lenalidomide. Isatuximab reduces Foxp3 and IL10 in Tregs and restores proliferation and function of Tcons. It augments multiple myeloma cell lysis by CD8
T and natural killer cells. Coculture of multiple myeloma cells with Tcons significantly induces Tregs (iTregs), which express even higher CD38, CD25, and FoxP3 than natural Tregs. This is associated with elevated circulating CD38
Tregs in multiple myeloma patients versus normal donors. Conversely, isatuximab decreases multiple myeloma cell- and bone marrow stromal cell-induced iTreg by inhibiting both cell-cell contact and TGFβ/IL10. Finally, CD38 levels correlate with differential inhibition by isatuximab of Tregs from multiple myeloma versus normal donors.
Targeting CD38 by isatuximab can preferentially block immunosuppressive Tregs and thereby restore immune effector function against multiple myeloma.
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The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Given its critical role in coordinating cardiac performance, a detailed ...analysis of the molecular mechanisms underlying conduction system formation should inform our understanding of arrhythmia pathophysiology and affect the development of novel therapeutic strategies. Historically, the ability to distinguish cells of the conduction system from neighboring working myocytes presented a major technical challenge for performing comprehensive mechanistic studies. Early lineage tracing experiments suggested that conduction cells derive from cardiomyocyte precursors, and these claims have been substantiated by using more contemporary approaches. However, regional specialization of conduction cells adds an additional layer of complexity to this system, and it appears that different components of the conduction system utilize unique modes of developmental formation. The identification of numerous transcription factors and their downstream target genes involved in regional differentiation of the conduction system has provided insight into how lineage commitment is achieved. Furthermore, by adopting cutting-edge genetic techniques in combination with sophisticated phenotyping capabilities, investigators have made substantial progress in delineating the regulatory networks that orchestrate conduction system formation and their role in cardiac rhythm and physiology. This review describes the connectivity of these gene regulatory networks in cardiac conduction system development and discusses how they provide a foundation for understanding normal and pathological human cardiac rhythms.
PD-1/PD-L1 signaling promotes tumor growth while inhibiting effector cell-mediated antitumor immune responses. Here, we assessed the impact of single and dual blockade of PD-1/PD-L1, alone or in ...combination with lenalidomide, on accessory and immune cell function as well as multiple myeloma cell growth in the bone marrow (BM) milieu.
Surface expression of PD-1 on immune effector cells, and PD-L1 expression on CD138(+) multiple myeloma cells and myeloid-derived suppressor cells (MDSC) were determined in BM from newly diagnosed (ND) multiple myeloma and relapsed/refractory (RR) multiple myeloma versus healthy donor (HD). We defined the impact of single and dual blockade of PD-1/PD-L1, alone and with lenalidomide, on autologous anti-multiple myeloma immune response and tumor cell growth.
Both ND and RR patient multiple myeloma cells have increased PD-L1 mRNA and surface expression compared with HD. There is also a significant increase in PD-1 expression on effector cells in multiple myeloma. Importantly, PD-1/PD-L1 blockade abrogates BM stromal cell (BMSC)-induced multiple myeloma growth, and combined blockade of PD-1/PD-L1 with lenalidomide further inhibits BMSC-induced tumor growth. These effects are associated with induction of intracellular expression of IFNγ and granzyme B in effector cells. Importantly, PD-L1 expression in multiple myeloma is higher on MDSC than on antigen-presenting cells, and PD-1/PD-L1 blockade inhibits MDSC-mediated multiple myeloma growth. Finally, lenalidomide with PD-1/PD-L1 blockade inhibits MDSC-mediated immune suppression.
Our data therefore demonstrate that checkpoint signaling plays an important role in providing the tumor-promoting, immune-suppressive microenvironment in multiple myeloma, and that PD-1/PD-L1 blockade induces anti-multiple myeloma immune response that can be enhanced by lenalidomide, providing the framework for clinical evaluation of combination therapy.
Although therapeutic strategies have been adapted to age and comorbidities for a long time, almost all multiple myeloma (MM) patients currently receive similar treatment, whatever their disease risk ...category. However, high-risk MM patients still constitute an unmet medical need and should benefit from the most efficient drug combinations. Herein, we review and discuss how to optimally define risk and why a revision of the current definition is urgently needed.
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BCMA targeting chimeric antigen receptor (CAR) T cell therapy has shown deep and durable responses in multiple myeloma. However, relapse following therapy is frequently observed, and mechanisms of ...resistance remain ill-defined. Here, we perform single cell genomic characterization of longitudinal samples from a patient who relapsed after initial CAR T cell treatment with lack of response to retreatment. We report selection, following initial CAR T cell infusion, of a clone with biallelic loss of BCMA acquired by deletion of one allele and a mutation that creates an early stop codon on the second allele. This loss leads to lack of CAR T cell proliferation following the second infusion and is reflected by lack of soluble BCMA in patient serum. Our analysis suggests the need for careful detection of BCMA gene alterations in multiple myeloma cells from relapse following CAR T cell therapy.
Development of the Cardiac Conduction System Bhattacharyya, Samadrita; Munshi, Nikhil V
Cold Spring Harbor perspectives in biology,
12/2020, Letnik:
12, Številka:
12
Journal Article
Recenzirano
Odprti dostop
The cardiac conduction system initiates and propagates each heartbeat. Specialized conducting cells are a well-conserved phenomenon across vertebrate evolution, although mammalian and avian species ...harbor specific components unique to organisms with four-chamber hearts. Early histological studies in mammals provided evidence for a dominant pacemaker within the right atrium and clarified the existence of the specialized muscular axis responsible for atrioventricular conduction. Building on these seminal observations, contemporary genetic techniques in a multitude of model organisms has characterized the developmental ontogeny, gene regulatory networks, and functional importance of individual anatomical compartments within the cardiac conduction system. This review describes in detail the transcriptional and regulatory networks that act during cardiac conduction system development and homeostasis with a particular emphasis on networks implicated in human electrical variation by large genome-wide association studies. We conclude with a discussion of the clinical implications of these studies and describe some future directions.
In this issue of Cell, Hulsmans et al. identify a subset of macrophages residing within the cardiac conduction system, which orchestrates cardiac rhythm. Macrophages directly couple with ...cardiomyocytes, and their perturbation alters cardiac conduction, suggesting that pharmacological manipulation of resident macrophages might represent a new strategy to combat cardiac arrhythmias.
In this issue of Cell, Hulsmans et al. identify a subset of macrophages residing within the cardiac conduction system, which orchestrates cardiac rhythm. Macrophages directly couple with cardiomyocytes, and their perturbation alters cardiac conduction, suggesting that pharmacological manipulation of resident macrophages might represent a new strategy to combat cardiac arrhythmias.
Autologous T cells engineered to express a chimeric antigen receptor specific for the B-cell maturation antigen produced responses in the majority of patients with refractory and resistant myeloma, ...including deep molecular responses in 26% of treated patients. High-grade hematologic toxic effects and cytokine release syndrome were common.
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