Experimental African trypanosome infection suppresses the development of multiple myeloma in mice by inducing intrinsic apoptosis of malignant plasma cells

Abstract Waldenström Macroglobulinemia (WM) is a disorder of lymphoplasmacytoid cells that inhabit lymph nodes and the bone marrow. WM cells are characterized by secretion of monoclonal pentameric IgM. These cells are CD19+, CD20+, CD22+, CD38+, CD138+/- and phenotypically resemble IgM plasmablasts or plasma cells. In addition, 91% of WM cases carry an activating mutation of MyD88 (L265P). Mature resting B cells can be driven to differentiate to IgM secreting plasmablasts and plasma cells with similar phenotypes using the TLR4 ligand lipopolysaccharide (LPS). We have demonstrated that LPS (+ cytokine)-differentiated cells become Bcl-xL dependent during this process, rendering them sensitive to the Bcl-xL/Bcl-2 inhibitor ABT-737. For this reason, we hypothesized that activation of MyD88 in WM cells could drive Bcl-xL dependence in a similar manner conferring ABT-737 sensitivity. We treated three WM cell lines, BCWM.1, MWCL-1 and RPCI-WM1 which all harbor the MyD88 (L265P) mutation with ABT-737. We found varying levels of resistance to ABT-737 with an IC50 > 2 μM for all three lines as compared with the ABT-737 sensitive multiple myeloma cell line MM.1s which has an IC50 of 0.4 μM. The RPCI-WM1 cell line was the most insensitive to ABT-737-induced apoptosis with no apoptosis above baseline up to 1.6 μM of drug. Since the WM cell lines were not sensitive to direct inhibition of intrinsic survival regulators, we then examined the sensitivity of these cell lines to other activators of the intrinsic apoptosis pathway. Two of the three cell lines were moderately sensitive to bortezomib with IC50 ≈ 5 nM as compared with the sensitive multiple myeloma cell line MM.1s with an IC50 of 2 nM. The RPCI-WM1 cell line was insensitive to bortezomib with no apoptosis above baseline up to 20 nM bortezomib. Similarly, we found that two of the cell lines were moderately sensitive to arsenic trioxide with an IC50 ≈ 6 μM as compared with the multiple myeloma cell line MM1.s (IC50 ≈ 4 μM). The RPCI-WM1 cell line was insensitive to ATO as well with an IC50 > 20 μM. Given the lack of sensitivity of the three WM cell lines we tested to Bcl-xL/Bcl-2 inhibition with ABT-737 treatment, and that RPCI-WM1 appears insensitive to multiple inducers of intrinsic apoptosis, we examined the expression levels of Bcl-2 family members in these cells. Both BCWM.1 cells and MWCL-1 cells expressed Bim mRNA at very low levels with MWCL-1 expressing no detectable Bim at the protein level. Surprisingly, more moderate levels of Bim were detected in RPCI-WM1 cells. These findings were confirmed at the mRNA level by qRT-PCR. Bcl-xL and Mcl-1 were detectable in all three lines at moderate levels while Bcl-2 which was only expressed at significant levels in MWCL-1 cells and undetectable in BCWM.1 cells. We examined the expression levels of the Bax and Bak in these cells and remarkably there was no detectable Bax and very small amounts of Bak protein in RPCI-WM1 cells. Consistent with a defect in gene expression, Bax mRNA was also low in RPCI-WM1. This was not due to copy number variation, as determined by array-CGH in both the initial patient isolate and the established cell line. Additionally, no loss of Bax, Bak or Bim (Bcl2l11) was observed in SNP array analysis of 46 patients with WM. Interestingly, Bak mRNA levels in RPCI-WM1 were similar to the other WM lines, suggesting a defect in translation or post-translational regulation is responsible for the low protein expression. These results lead us to conclude that these WM cell lines are not sensitive to Bcl-xL/ Bcl-2 inhibition despite activation of MyD88. We have further shown that there are multiple and distinct differences in Bcl-2 family protein expression that lead to this insensitivity. While low levels of Bim combined with expression of Mcl-1 confer resistance to ABT-737 in MWCL-1 and BCWM.1, the lack of Bax and Bak confers resistance to intrinsic apoptotic stimuli in general in RPCI-WM1. Moreover, the loss of Bax and Bak protein expression occur through distinct mechanisms. These WM cell lines demonstrate that sensitivity to agents that kill through the intrinsic apoptotic pathway may vary within a disease that is characterized by a single activating mutation and suggests that additional heterogeneous events regulate the expression of Bcl-2 family proteins in WM. Disclosures: Leleu: CELGENE: Honoraria; JANSSEN: Honoraria. Lonial:Millennium: Consultancy; Celgene: Consultancy; Novartis: Consultancy; BMS: Consultancy; Sanofi: Consultancy; Onyx: Consultancy. Boise:Onyx Pharmaceuticals: Consultancy.

Download Full-text

Circulating CD19+ cells in multiple myeloma are clonaly related to the end stage malignant plasma cells in the bone marrow

Immunology Letters ◽

10.1016/s0165-2478(97)88160-6 ◽

1997 ◽

Vol 56 (1-3) ◽

pp. 327

Author(s):

A Szczepek

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Plasma Cells ◽

End Stage

Download Full-text

Bone disease as the first manifestation of systemic AL-amyloidosis

Terapevticheskii arkhiv ◽

10.26442/00403660.2020.07.000775 ◽

2020 ◽

Vol 92 (7) ◽

pp. 85-89

Author(s):

L. P. Mendeleeva ◽

I. G. Rekhtina ◽

A. M. Kovrigina ◽

I. E. Kostina ◽

V. A. Khyshova ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Bone Disease ◽

Plasma Cells ◽

Interventricular Septum ◽

Bone Destruction ◽

Amyloid Deposition ◽

Bone Lesions ◽

Al Amyloidosis ◽

Linear Type

Our case demonstrates severe bone disease in primary AL-amyloidosis without concomitant multiple myeloma. A 30-year-old man had spontaneous vertebral fracture Th8. A computed tomography scan suggested multiple foci of lesions in all the bones. In bone marrow and resected rib werent detected any tumor cells. After 15 years from the beginning of the disease, nephrotic syndrome developed. Based on the kidney biopsy, AL-amyloidosis was confirmed. Amyloid was also detected in the bowel and bone marrow. On the indirect signs (thickening of the interventricular septum 16 mm and increased NT-proBNP 2200 pg/ml), a cardial involvement was confirmed. In the bone marrow (from three sites) was found 2.85% clonal plasma cells with immunophenotype СD138+, СD38dim, СD19-, СD117+, СD81-, СD27-, СD56-. FISH method revealed polysomy 5,9,15 in 3% of the nuclei. Serum free light chain Kappa 575 mg/l (/44.9) was detected. Multiple foci of destruction with increased metabolic activity (SUVmax 3.6) were visualized on PET-CT, and an surgical intervention biopsy was performed from two foci. The number of plasma cells from the destruction foci was 2.5%, and massive amyloid deposition was detected. On CT scan foci of lesions differed from bone lesions at multiple myeloma. Bone fragments of point and linear type (button sequestration) were visualized in most of the destruction foci. The content of the lesion was low density. There was no extraossal spread from large zones of destruction. There was also spontaneous scarring of the some lesions (without therapy). Thus, the diagnosis of multiple myeloma was excluded on the basis based on x-ray signs, of the duration of osteodestructive syndrome (15 years), the absence of plasma infiltration in the bone marrow, including from foci of bone destruction by open biopsy. This observation proves the possibility of damage to the skeleton due to amyloid deposition and justifies the need to include AL-amyloidosis in the spectrum of differential diagnosis of diseases that occur with osteodestructive syndrome.

Download Full-text

Impact of Natural Dietary Agents on Multiple Myeloma Prevention and Treatment: Molecular Insights and Potential for Clinical Translation

Current Medicinal Chemistry ◽

10.2174/0929867325666180629153141 ◽

2020 ◽

Vol 27 (2) ◽

pp. 187-215 ◽

Cited By ~ 8

Author(s):

Lavinia Raimondi ◽

Angela De Luca ◽

Gianluca Giavaresi ◽

Agnese Barone ◽

Pierosandro Tagliaferri ◽

...

Keyword(s):

Signal Transduction ◽

Multiple Myeloma ◽

Natural Products ◽

Bone Disease ◽

Molecular Mechanisms ◽

Plasma Cells ◽

Hematologic Malignancy ◽

Signal Transduction Pathways ◽

Pharmacologically Active ◽

Dietary Agents

: Chemoprevention is based on the use of non-toxic, pharmacologically active agents to prevent tumor progression. In this regard, natural dietary agents have been described by the most recent literature as promising tools for controlling onset and progression of malignancies. Extensive research has been so far performed to shed light on the effects of natural products on tumor growth and survival, disclosing the most relevant signal transduction pathways targeted by such compounds. Overall, anti-inflammatory, anti-oxidant and cytotoxic effects of dietary agents on tumor cells are supported either by results from epidemiological or animal studies and even by clinical trials. : Multiple myeloma is a hematologic malignancy characterized by abnormal proliferation of bone marrow plasma cells and subsequent hypercalcemia, renal dysfunction, anemia, or bone disease, which remains incurable despite novel emerging therapeutic strategies. Notably, increasing evidence supports the capability of dietary natural compounds to antagonize multiple myeloma growth in preclinical models of the disease, underscoring their potential as candidate anti-cancer agents. : In this review, we aim at summarizing findings on the anti-tumor activity of dietary natural products, focusing on their molecular mechanisms, which include inhibition of oncogenic signal transduction pathways and/or epigenetic modulating effects, along with their potential clinical applications against multiple myeloma and its related bone disease.

Download Full-text

Ruxolitinib Regulates the Autophagy Machinery in Multiple Myeloma Cells

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520620666200218105159 ◽

2020 ◽

Vol 20 (18) ◽

pp. 2316-2323 ◽

Cited By ~ 3

Author(s):

Alican Kusoglu ◽

Bakiye G. Bagca ◽

Neslihan P.O. Ay ◽

Guray Saydam ◽

Cigir B. Avci

Keyword(s):

Multiple Myeloma ◽

Cell Line ◽

B Lymphocyte ◽

Plasma Cells ◽

Annexin V ◽

Myeloma Cell ◽

Control Group ◽

Multiple Myeloma Cell ◽

Ic50 Values ◽

Stat Pathway

Background: Ruxolitinib is a selective JAK1/2 inhibitor approved by the FDA for myelofibrosis in 2014 and nowadays, comprehensive investigations on the potential of the agent as a targeted therapy for haematological malignancies are on the rise. In multiple myeloma which is a cancer of plasma cells, the Interleukin- 6/JAK/STAT pathway is emerging as a therapeutic target since the overactivation of the pathway is associated with poor prognosis. Objective: In this study, our purpose was to discover the potential anticancer effects of ruxolitinib in ARH-77 multiple myeloma cell line compared to NCI-BL 2171 human healthy B lymphocyte cell line. Methods: Cytotoxic effects of ruxolitinib in ARH-77 and NCI-BL 2171 cells were determined via WST-1 assay. The autophagy mechanism induced by ruxolitinib measured by detecting autophagosome formation was investigated. Apoptotic effects of ruxolitinib were analyzed with Annexin V-FITC Detection Kit and flow cytometry. We performed RT-qPCR to demonstrate the expression changes of the genes in the IL-6/JAK/STAT pathway in ARH-77 and NCI-BL 2171 cells treated with ruxolitinib. Results: We identified the IC50 values of ruxolitinib for ARH-77 and NCI-BL 2171 as 20.03 and 33.9μM at the 72nd hour, respectively. We showed that ruxolitinib induced autophagosome accumulation by 3.45 and 1.70 folds in ARH-77 and NCI-BL 2171 cells compared to the control group, respectively. Treatment with ruxolitinib decreased the expressions of IL-6, IL-18, JAK2, TYK2, and AKT genes, which play significant roles in MM pathogenesis. Conclusion: All in all, ruxolitinib is a promising agent for the regulation of the IL-6/JAK/STAT pathway and interferes with the autophagy mechanism in MM.

Download Full-text

Bioactive Compounds from Herbal Medicine Targeting Multiple Myeloma

Applied Sciences ◽

10.3390/app11104451 ◽

2021 ◽

Vol 11 (10) ◽

pp. 4451

Author(s):

Coralia Cotoraci ◽

Alina Ciceu ◽

Alciona Sasu ◽

Eftimie Miutescu ◽

Anca Hermenean

Keyword(s):

Multiple Myeloma ◽

Survival Rate ◽

Plasma Cells ◽

Inhibition Of Proliferation ◽

In Vivo Experiments ◽

Clonal Proliferation ◽

Hematological Cancers ◽

Monoclonal Proteins

Multiple myeloma (MM) is one of the most widespread hematological cancers. It is characterized by a clonal proliferation of malignant plasma cells in the bone marrow and by the overproduction of monoclonal proteins. In recent years, the survival rate of patients with multiple myeloma has increased significantly due to the use of transplanted stem cells and of the new therapeutic agents that have significantly increased the survival rate, but it still cannot be completely cured and therefore the development of new therapeutic products is needed. Moreover, many patients have various side effects and face the development of drug resistance to current therapies. The purpose of this review is to highlight the bioactive active compounds (flavonoids) and herbal extracts which target dysregulated signaling pathway in MM, assessed by in vitro and in vivo experiments or clinical studies, in order to explore their healing potential targeting multiple myeloma. Mechanistically, they demonstrated the ability to promote cell cycle blockage and apoptosis or autophagy in cancer cells, as well as inhibition of proliferation/migration/tumor progression, inhibition of angiogenesis in the tumor vascular network. Current research provides valuable new information about the ability of flavonoids to enhance the apoptotic effects of antineoplastic drugs, thus providing viable therapeutic options based on combining conventional and non-conventional therapies in MM therapeutic protocols.

Download Full-text

Crosstalk between endoplasmic reticulum stress and oxidative stress: a dynamic duo in multiple myeloma

Cellular and Molecular Life Sciences ◽

10.1007/s00018-021-03756-3 ◽

2021 ◽

Author(s):

Sinan Xiong ◽

Wee-Joo Chng ◽

Jianbiao Zhou

Keyword(s):

Oxidative Stress ◽

Multiple Myeloma ◽

Endoplasmic Reticulum ◽

Er Stress ◽

Cell Fate ◽

Stress Responses ◽

Plasma Cells ◽

Reactive Oxygen Species Generation ◽

Future Research ◽

And Oxidative Stress

AbstractUnder physiological and pathological conditions, cells activate the unfolded protein response (UPR) to deal with the accumulation of unfolded or misfolded proteins in the endoplasmic reticulum. Multiple myeloma (MM) is a hematological malignancy arising from immunoglobulin-secreting plasma cells. MM cells are subject to continual ER stress and highly dependent on the UPR signaling activation due to overproduction of paraproteins. Mounting evidence suggests the close linkage between ER stress and oxidative stress, demonstrated by overlapping signaling pathways and inter-organelle communication pivotal to cell fate decision. Imbalance of intracellular homeostasis can lead to deranged control of cellular functions and engage apoptosis due to mutual activation between ER stress and reactive oxygen species generation through a self-perpetuating cycle. Here, we present accumulating evidence showing the interactive roles of redox homeostasis and proteostasis in MM pathogenesis and drug resistance, which would be helpful in elucidating the still underdefined molecular pathways linking ER stress and oxidative stress in MM. Lastly, we highlight future research directions in the development of anti-myeloma therapy, focusing particularly on targeting redox signaling and ER stress responses.

Download Full-text

Myocardial amyloidosis following multiple myeloma in a 38-year-old female patient: A case report

Open Medicine ◽

10.1515/med-2020-0125 ◽

2020 ◽

Vol 15 (1) ◽

pp. 396-402

Author(s):

Qisi Zhang ◽

Yingli Qiao ◽

Dongmei Yan ◽

Yuhui Deng ◽

Mengyang Zhang ◽

...

Keyword(s):

Multiple Myeloma ◽

Plasma Cells ◽

Laboratory Data ◽

Young Patients ◽

Clinical Manifestations ◽

The Elderly ◽

First Episode ◽

Rapid Progression ◽

Congo Red Staining ◽

Impaired Cardiac Function

AbstractMultiple myeloma (MM) is an immunoglobulin-producing tumor of plasma cells, which occurs commonly in the elderly. The incidence of myocardial amyloidosis with MM is extremely low and early clinical manifestations are nonspecific. The diversity of clinical manifestations and first episode symptoms often cause misdiagnosis in young patients with myocardial amyloidosis following MM. In this study, we analyzed the clinical data of a young woman with MM and impaired cardiac function combined with echocardiography, electrocardiography (ECG), laboratory data, cell Congo Red staining, and other manifestations to diagnose amyloidosis. Considering the rapid progression, short survival, and poor prognosis in most patients, a clear, definitive, and timely diagnosis is essential for the treatment of patients with MM complicated with myocardial amyloidosis.

Download Full-text

Plasma cells in multiple myeloma express a natural killer cell- associated antigen: CD56 (NKH-1; Leu-19)

Blood ◽

10.1182/blood.v76.2.377.377 ◽

1990 ◽

Vol 76 (2) ◽

pp. 377-382 ◽

Cited By ~ 194

Author(s):

B Van Camp ◽

BG Durie ◽

C Spier ◽

M De Waele ◽

I Van Riet ◽

...

Keyword(s):

Multiple Myeloma ◽

Natural Killer Cell ◽

Natural Killer ◽

Plasma Cells ◽

Killer Cell ◽

Neoplastic Tissue ◽

Aggressive Disease ◽

Reactive Plasma ◽

Gut Mucosa ◽

Cd56 Expression

Abstract Bone marrow samples from 55 patients with multiple myeloma (MM) and 23 patients with monoclonal gammopathy of undertermined significance (MGUS) were evaluated with a broad panel of monoclonal antibodies. Plasma cells from 78% (43/55) of patients with MM strongly expressed the natural killer cell antigen CD56 (NKH-1, Leu-19). Of the 23 patients with MGUS, none showed strong CD56 reactivity, although three had weak reactivity in less than 20% of plasma cells. Myeloma cells expressing CD56 did not coexpress the CD57 or CD16 antigens. Patients with CD56-positive plasma cells had both indolent and aggressive disease. However, the 12 CD56-negative patients had predominantly aggressive disease with an unexpected preponderance of kappa Bence Jones only myeloma (5/10[50%] evaluable patients). Polyclonal plasma cells from non-neoplastic tissue sites (normal bone marrows, lymph nodes, tonsillar biopsies, and gut-mucosa biopsies) showed a near absence of CD56. We conclude that isolated, strong CD56 expression is common in MM, but not in MGUS or reactive plasma cells. The potential biologic importance of CD56 positivity in myeloma is reviewed.

Download Full-text