Multiple Myeloma: Molecular Pathogenesis and Disease Evolution

Background: Multiple myeloma is the second most common hematologic malignancy, which to date remains incurable despite advances in treatment strategies including the use of novel substances such as proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies. Summary: The bone marrow-based disease is preceded by the 2 sequential premalignant conditions: monoclonal gammopathy of undetermined significance and smoldering myeloma. Plasma cell leukemia and extramedullary disease occur, when malignant clones lose their dependency on the bone marrow. Key genetic features of these plasma cell dyscrasias include chromosomal aberrations such as translocations and hyperdiploidy, which occur during error-prone physiologic processes in B-cell development. Next-generation sequencing studies have identified mutations in major oncogenic pathways and tumor suppressors, which contribute to the pathogenesis of multiple myeloma and have revealed insights into the clonal evolution of the disease, particularly along different lines of therapy. More recently, the importance of epigenetic alterations and the role of the bone marrow microenvironment, including immune and osteogenic cells, have become evident. Key Messages: We herein review the current knowledge of the pathogenesis of multiple myeloma, which is crucial for the development of novel targeted therapeutic strategies. These can contribute to the endeavor to make multiple myeloma a curable disease.

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Mechanisms of Immune Evasion in Multiple Myeloma: Open Questions and Therapeutic Opportunities

Cancers ◽

10.3390/cancers13133213 ◽

2021 ◽

Vol 13 (13) ◽

pp. 3213

Author(s):

Cirino Botta ◽

Francesco Mendicino ◽

Enrica Antonia Martino ◽

Ernesto Vigna ◽

Domenica Ronchetti ◽

...

Keyword(s):

Multiple Myeloma ◽

Intermediate Phase ◽

Hematologic Malignancy ◽

Treatment Strategies ◽

Current Treatment ◽

System Control ◽

Disease Evolution ◽

Bm Niche ◽

Open Questions ◽

Asymptomatic Stage

Multiple myeloma (MM) is the second most common hematologic malignancy, characterized by a multi-step evolutionary path, which starts with an early asymptomatic stage, defined as monoclonal gammopathy of undetermined significance (MGUS) evolving to overt disease in 1% of cases per year, often through an intermediate phase known as “smoldering” MM (sMM). Interestingly, while many genomic alterations (translocation, deletions, mutations) are usually found at early stages, they are not sufficient (alone) to determine disease evolution. The latter, indeed, relies on significant “epigenetic” alterations of different normal cell populations within the bone marrow (BM) niche, including the “evasion” from immune-system control. Additionally, MM cells could “educate” the BM immune microenvironment (BM-IM) towards a pro-inflammatory and immunosuppressive phenotype, which ultimately leads to disease evolution, drug resistance, and patients’ worse outcome. Indeed, it is not a case that the most important drugs for the treatment of MM include immunomodulatory agents (thalidomide, lenalidomide, and pomalidomide) and monoclonal antibodies (daratumumab, isatuximab, and elotuzumab). On these bases, in this review, we describe the most recent advances in the comprehension of the role of the different cells composing the BM-IM, and we discuss the potential molecular targets, which could represent new opportunities to improve current treatment strategies for MM patients.

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The Role of AP-1 Transcription Factors in Plasma Cell Biology and Multiple Myeloma Pathophysiology

Cancers ◽

10.3390/cancers13102326 ◽

2021 ◽

Vol 13 (10) ◽

pp. 2326

Author(s):

Fengjuan Fan ◽

Klaus Podar

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Transcription Factors ◽

Cell Differentiation ◽

Plasma Cell ◽

Cell Biology ◽

Hematologic Malignancy ◽

Family Members ◽

Plasma Cell Differentiation

Multiple myeloma (MM) is an incurable hematologic malignancy characterized by the clonal expansion of malignant plasma cells within the bone marrow. Activator Protein-1 (AP-1) transcription factors (TFs), comprised of the JUN, FOS, ATF and MAF multigene families, are implicated in a plethora of physiologic processes and tumorigenesis including plasma cell differentiation and MM pathogenesis. Depending on the genetic background, the tumor stage, and cues of the tumor microenvironment, specific dimeric AP-1 complexes are formed. For example, AP-1 complexes containing Fra-1, Fra-2 and B-ATF play central roles in the transcriptional control of B cell development and plasma cell differentiation, while dysregulation of AP-1 family members c-Maf, c-Jun, and JunB is associated with MM cell proliferation, survival, drug resistance, bone marrow angiogenesis, and bone disease. The present review article summarizes our up-to-date knowledge on the role of AP-1 family members in plasma cell differentiation and MM pathophysiology. Moreover, it discusses novel, rationally derived approaches to therapeutically target AP-1 TFs, including protein-protein and protein-DNA binding inhibitors, epigenetic modifiers and natural products.

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Deficient Drug Transporter Function of Bone Marrow–Localized and Leukemic Plasma Cells in Multiple Myeloma

Blood ◽

10.1182/blood.v90.9.3751 ◽

1997 ◽

Vol 90 (9) ◽

pp. 3751-3759 ◽

Cited By ~ 40

Author(s):

Linda M. Pilarski ◽

Agnieszka J. Szczepek ◽

Andrew R. Belch

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

B Cells ◽

Plasma Cell ◽

Drug Transport ◽

Plasma Cells ◽

Phenotypic Expression ◽

Treatment Strategies ◽

Cell Stage

Abstract Although chemotherapy effectively reduces the plasma cell burden in multiple myeloma (MM), the disease recurs. MM includes circulating and bone marrow (BM) localized components. A large majority of circulating CD11b+ MM B cells (81%) express an IgH VDJ rearrangement identical to that of autologous BM plasma cells. Unlike plasma cells, these monoclonal circulating B cells exhibit dye and drug transport activity before and throughout chemotherapy. Drug resistance was measured as the ability to export the fluorescent dye Rhodamine123 (Rh123) or the drug adriamycin, using flow cytometry. The role of P-glycoprotein 170 (P-gp), the multidrug transporter, was defined by cyclosporin A (CsA)-sensitive dye export. Only 8% to 11% of BM-localized plasma cells exported dye with the majority retaining dye, identified as bright staining. Circulating leukemic plasma cells were also unable to export dye and remained Rh123bright. However, 53% of circulating clonotypic MM B cells exhibited CsA-sensitive dye export. BM plasma cells taken before or after initiation of first line chemotherapy were equally unable to export dye. Thus in myeloma, differentiation to the plasma cell stage is accompanied by a loss of P-gp function, although P-gp phenotypic expression is retained. In contrast, for monoclonal gammopathy of undetermined significance (MGUS), 54% of BM-localized plasma cells exported dye, comparable to the 53% of circulating MGUS B cells that also exported dye, suggesting that the apparent defect in P-gp function is unique to myeloma plasma cells. Virtually all BM plasma cells in MM retained the drug adriamycin, consistent with their initial drug sensitivity in vivo, in contrast to circulating MM B cells, or to T cells in BM or blood. Thus, circulating B cells appear to be the predominant drug resistant component of the MM B-lineage hierarchy. This report suggests that successful therapeutic strategies will be those that target circulating B cells. Chemosensitization methods involving inhibition of P-gp are likely to improve depletion of these cells by compromising their ability to exclude drug. This work suggests that circulating clonotypic B cells should be monitored in clinical trials to confirm their depletion and the overall efficacy of novel treatment strategies.

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Treatment Strategies Considering Micro-Environment and Clonal Evolution in Multiple Myeloma

Cancers ◽

10.3390/cancers13020215 ◽

2021 ◽

Vol 13 (2) ◽

pp. 215

Author(s):

Kazuhito Suzuki ◽

Kaichi Nishiwaki ◽

Shingo Yano

Keyword(s):

Multiple Myeloma ◽

Drug Resistance ◽

De Novo ◽

Clonal Evolution ◽

Proteasome Inhibitors ◽

Treatment Strategies ◽

Neutral Evolution ◽

Acquired Drug Resistance ◽

Immunological Surveillance

Multiple myeloma is an uncurable hematological malignancy because of obtained drug resistance. Microenvironment and clonal evolution induce myeloma cells to develop de novo and acquired drug resistance, respectively. Cell adhesion-mediated drug resistance, which is induced by the interaction between myeloma and bone marrow stromal cells, and soluble factor-mediated drug resistance, which is induced by cytokines and growth factors, are two types of de novo drug resistance. The microenvironment, including conditions such as hypoxia, vascular and endosteal niches, contributes toward de novo drug resistance. Clonal evolution was associated with acquired drug resistance and classified as branching, linear, and neutral evolutions. The branching evolution is dependent on the microenvironment and escape of immunological surveillance while the linear and neutral evolution is independent of the microenvironment and associated with aggressive recurrence and poor prognosis. Proteasome inhibitors (PIs), immunomodulatory drugs (IMiDs), monoclonal antibody agents (MoAbs), and autologous stem cell transplantation (ASCT) have improved prognosis of myeloma via improvement of the microenvironment. The initial treatment plays the most important role considering de novo and acquired drug resistance and should contain PIs, IMIDs, MoAb and ASCT. This review summarizes the role of anti-myeloma agents for microenvironment and clonal evolution and treatment strategies to overcome drug resistance.

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Towards Molecular Profiling in Multiple Myeloma: A Literature Review and Early Indications of Its Efficacy for Informing Treatment Strategies

International Journal of Molecular Sciences ◽

10.3390/ijms19072087 ◽

2018 ◽

Vol 19 (7) ◽

pp. 2087 ◽

Cited By ~ 9

Author(s):

Wolfgang Willenbacher ◽

Andreas Seeber ◽

Normann Steiner ◽

Ella Willenbacher ◽

Zoran Gatalica ◽

...

Keyword(s):

Multiple Myeloma ◽

Plasma Cells ◽

Hematologic Malignancy ◽

Proteasome Inhibitors ◽

Treatment Strategies ◽

Gene Mutations ◽

Molecular Profiling ◽

Complex Dynamic ◽

Therapeutic Implications ◽

The Past

Multiple myeloma (MM), the second most common hematologic malignancy, is characterized by the clonal expansion of plasma cells. Despite dramatic improvements in patients′ survival over the past decade due to advances in therapy exploiting novel molecular targets (immunomodulatory drugs, proteasome inhibitors and monoclonal antibodies), the treatment of relapsed and refractory disease remains challenging. Recent studies confirmed complex, dynamic, and heterogeneous genomic alterations without unifying gene mutations in MM patients. In the current review, we survey recent therapeutic strategies, as well as molecular profiling data on MM, with emphasis on relapsed and refractory cases. A critical appraisal of novel findings and of their potential therapeutic implications will be discussed in detail, along with the author’s own experiences/views.

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Cellular Mechanisms of Multiple Myeloma Bone Disease

Clinical and Developmental Immunology ◽

10.1155/2013/289458 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 38

Author(s):

Angela Oranger ◽

Claudia Carbone ◽

Maddalena Izzo ◽

Maria Grano

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Bone Disease ◽

Plasma Cells ◽

Negative Impact ◽

Current Knowledge ◽

Hematologic Malignancy ◽

Cell Activity ◽

Bone Lesions ◽

Pathologic Fractures

Multiple myeloma (MM) is a hematologic malignancy of differentiated plasma cells that accumulates and proliferates in the bone marrow. MM patients often develop bone disease that results in severe bone pain, osteolytic lesions, and pathologic fractures. These skeletal complications have not only a negative impact on quality of life but also a possible effect in overall survival. MM osteolytic bone lesions arise from the altered bone remodeling due to both increased osteoclast activation and decreased osteoblast differentiation. A dysregulated production of numerous cytokines that can contribute to the uncoupling of bone cell activity is well documented in the bone marrow microenvironment of MM patients. These molecules are produced not only by malignant plasma cells, that directly contribute to MM bone disease, but also by bone, immune, and stromal cells interacting with each other in the bone microenvironment. This review focuses on the current knowledge of MM bone disease biology, with particular regard on the role of bone and immune cells in producing cytokines critical for malignant plasma cell proliferation as well as in osteolysis development. Therefore, the understanding of MM pathogenesis could be useful to the discovery of novel agents that will be able to both restore bone remodelling and reduce tumor burden.

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Boosting Immunity against Multiple Myeloma

Cancers ◽

10.3390/cancers13061221 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1221

Author(s):

Raquel Lopes ◽

Bruna Velosa Ferreira ◽

Joana Caetano ◽

Filipa Barahona ◽

Emilie Arnault Carneiro ◽

...

Keyword(s):

Multiple Myeloma ◽

Residual Disease ◽

Proteasome Inhibitors ◽

Treatment Strategies ◽

Complete Response ◽

Drug Conjugates ◽

Incurable Disease ◽

Car T ◽

Patient’S Outcome ◽

The Impact

Despite the improvement of patient’s outcome obtained by the current use of immunomodulatory drugs, proteasome inhibitors or anti-CD38 monoclonal antibodies, multiple myeloma (MM) remains an incurable disease. More recently, the testing in clinical trials of novel drugs such as anti-BCMA CAR-T cells, antibody–drug conjugates or bispecific antibodies broadened the possibility of improving patients’ survival. However, thus far, these treatment strategies have not been able to steadily eliminate all malignant cells, and the aim has been to induce a long-term complete response with minimal residual disease (MRD)-negative status. In this sense, approaches that target not only myeloma cells but also the surrounding microenvironment are promising strategies to achieve a sustained MRD negativity with prolonged survival. This review provides an overview of current and future strategies used for immunomodulation of MM focusing on the impact on bone marrow (BM) immunome.

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Role and Modulation of NK Cells in Multiple Myeloma

Hemato ◽

10.3390/hemato2020010 ◽

2021 ◽

Vol 2 (2) ◽

pp. 167-181

Author(s):

Marie Thérèse Rubio ◽

Adèle Dhuyser ◽

Stéphanie Nguyen

Keyword(s):

Multiple Myeloma ◽

Monoclonal Antibodies ◽

Nk Cells ◽

Tumor Cells ◽

Nk Cell ◽

Ex Vivo ◽

Killer Cell ◽

Proteasome Inhibitors ◽

Disease Evolution ◽

Cell Functions

Myeloma tumor cells are particularly dependent on their microenvironment and sensitive to cellular antitumor immune response, including natural killer (NK) cells. These later are essential innate lymphocytes implicated in the control of viral infections and cancers. Their cytotoxic activity is regulated by a balance between activating and inhibitory signals resulting from the complex interaction of surface receptors and their respective ligands. Myeloma disease evolution is associated with a progressive alteration of NK cell number, phenotype and cytotoxic functions. We review here the different therapeutic approaches that could restore or enhance NK cell functions in multiple myeloma. First, conventional treatments (immunomodulatory drugs-IMids and proteasome inhibitors) can enhance NK killing of tumor cells by modulating the expression of NK receptors and their corresponding ligands on NK and myeloma cells, respectively. Because of their ability to kill by antibody-dependent cell cytotoxicity, NK cells are important effectors involved in the efficacy of anti-myeloma monoclonal antibodies targeting the tumor antigens CD38, CS1 or BCMA. These complementary mechanisms support the more recent therapeutic combination of IMids or proteasome inhibitors to monoclonal antibodies. We finally discuss the ongoing development of new NK cell-based immunotherapies, such as ex vivo expanded killer cell immunoglobulin-like receptors (KIR)-mismatched NK cells, chimeric antigen receptors (CAR)-NK cells, check point and KIR inhibitors.

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Establishment of Cell Lines from Both Myeloma Bone Marrow and Plasmacytoma: SNU_MM1393_BM and SNU_MM1393_SC from a Single Patient

BioMed Research International ◽

10.1155/2014/510408 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Youngil Koh ◽

Woo-June Jung ◽

Kwang-Sung Ahn ◽

Sung-Soo Yoon

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Cell Lines ◽

Mononuclear Cells ◽

Cultured Cells ◽

Clonal Evolution ◽

Myeloma Cell ◽

Mouse Bone Marrow ◽

Single Patient ◽

U266 Cell

Purpose.We tried to establish clinically relevant human myeloma cell lines that can contribute to the understanding of multiple myeloma (MM).Materials and Methods.Mononuclear cells obtained from MM patient’s bone marrow were injected via tail vein in an NRG/SCID mouse. Fourteen weeks after the injection, tumor developed at subcutis of the mouse. The engraftment of MM cells into mouse bone marrow (BM) was also observed. We separated and cultured cells from subcutis and BM.Results.After the separation and culture of cells from subcutis and BM, we established two cell lines originating from a single patient (SNU_MM1393_BM and SNU_MM1393_SC). Karyotype of the two newly established MM cell lines showed tetraploidy which is different from the karyotype of the patient (diploidy) indicating clonal evolution. In contrast to SNU_MM1393_BM, cell proliferation of SNU_MM1393_SC was IL-6 independent. SNU_MM1393_BM and SNU_MM1393_SC showed high degree of resistance against bortezomib compared to U266 cell line. SNU_MM1393_BM had the greater lethality compared to SNU_MM1393_SC.Conclusion.Two cell lines harboring different site tropisms established from a single patient showed differences in cytokine response and lethality. Our newly established cell lines could be used as a tool to understand the biology of multiple myeloma.

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Multiple myeloma: circulating lymphocytes that express plasma cell antigens

Blood ◽

10.1182/blood.v64.2.352.bloodjournal642352 ◽

1984 ◽

Vol 64 (2) ◽

pp. 352-356

Author(s):

GJ Ruiz-Arguelles ◽

JA Katzmann ◽

PR Greipp ◽

NJ Gonchoroff ◽

JP Garton ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Plasma Cell ◽

Peripheral Blood ◽

Plasma Cells ◽

Peripheral Blood Lymphocytes ◽

Tumor Burden ◽

B Cell Differentiation ◽

Blood Lymphocytes ◽

Bone Marrow Plasma

The bone marrow and peripheral blood of 14 patients with multiple myeloma were studied with murine monoclonal antibodies that identify antigens on plasma cells (R1–3 and OKT10). Peripheral blood lymphocytes expressing plasma cell antigens were found in six cases. Five of these cases expressed the same antigens that were present on the plasma cells in the bone marrow. Patients that showed such peripheral blood involvement were found to have a larger tumor burden and higher bone marrow plasma cell proliferative activity. In some patients, antigens normally found at earlier stages of B cell differentiation (B1, B2, and J5) were expressed by peripheral blood lymphocytes and/or bone marrow plasma cells.

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