scholarly journals CHEK1 and circCHEK1_246aa Promote Multiple Myeloma Malignancy By Evoking Chromosomal Instability and Bone Lesion

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 9-10
Author(s):  
Ye Yang ◽  
Chunyan Gu ◽  
Wang Wang ◽  
Xiaozhu Tang
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Drug Resistance ◽  
Chromosomal Instability ◽  
Cellular Proliferation ◽  
Plasma Cells ◽  
Osteoclast Differentiation ◽  
Bone Lesion ◽  
Catalytic Center ◽  
Bm Niche

Key findings CHEK1 and circCHEK1_246aa induce multiple myeloma cell proliferation, drug resistance, and bone lesion formation CHEK1 and circCHEK1_246aa evoke myeloma chromosomal instability, partially through CEP170 activation Abstract Multiple myeloma (MM) is characterized by clonal expansion of plasma cells in the bone marrow (BM). Therefore, effective therapeutic interventions must target both myeloma cells and the BM niche. In the present study, we first demonstrated that CHEK1 expression was significantly increased in human MM samples relative to normal plasma cells, and that in MM patients, high CHEK1 expression was associated with poor outcomes. CHEK1 overexpression increased cellular proliferation in MM cells and evoked drug resistance in vitro, while CHEK1 knockdown abrogated this effect. Moreover, CHEK1 was a high-risk gene for poor outcome in MM patients, and, in paired samples from MM patients taken from newly diagnosed and relapsed MM, CHEK1 expression was upregulated. CHEK1-mediated increases in cell proliferation and drug resistance were due in part to CHEK1-induced chromosomal instability (CIN), as demonstrated by Giemsa staining, exon sequencing, and immunofluorescence. CHEK1 activated CIN, partly by phosphorylating CEP170. Interestingly, CHEK1 promoted osteoclast differentiation by direct phosphorylation and activation of NFATc1, indicating that CHEK1 inhibition could target both MM cell proliferation and macrophage osteoclast differentiation in the BM niche. Intriguingly, we also discovered that MM cells expressed circCHEK1_246aa, a circular CHEK1 RNA, which encoded and was translated to the CHEK1 kinase catalytic center. Transfection of circCHEK1_246aa increased MM CIN and osteoclast differentiation similarly to CHEK1 overexpression, suggesting that MM cells could secrete circCHEK1_246aa in the BM niche to increase the invasive potential of MM cells and promote osteoclast differentiation. Finally, we demonstrated in vivo in xenograft models that CHEK1 overexpression prompted MM proliferation and drug resistance, while CHEK1 knockdown conversely inhibited MM growth. Together, these findings suggest that targeting the enzymatic catalytic center encoded by CHEK1 mRNA and circCHEK1_246aa is a promising therapeutic modality to target both MM cells and the BM niche. Figure Disclosures No relevant conflicts of interest to declare.

scholarly journals CHEK1 and circCHEK1_246aa evoke chromosomal instability and induce bone lesion formation in multiple myeloma

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Chunyan Gu ◽  
Wang Wang ◽  
Xiaozhu Tang ◽  
Tingting Xu ◽  
Yanxin Zhang ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Drug Resistance ◽  
Chromosomal Instability ◽  
Plasma Cells ◽  
Osteoclast Differentiation ◽  
Bone Lesion ◽  
Catalytic Center ◽  
Bm Niche

Abstract Background Multiple myeloma (MM) is still incurable and characterized by clonal expansion of plasma cells in the bone marrow (BM). Therefore, effective therapeutic interventions must target both myeloma cells and the BM niche. Methods Cell proliferation, drug resistance, and chromosomal instability (CIN) induced by CHEK1 were confirmed by Giemsa staining, exon sequencing, immunofluorescence and xenograft model in vivo. Bone lesion was evaluated by Tartrate-resistant acid phosphatase (TRAP) staining. The existence of circCHEK1_246aa was evaluated by qPCR, Sanger sequencing and Mass Spectrometer. Results We demonstrated that CHEK1 expression was significantly increased in human MM samples relative to normal plasma cells, and that in MM patients, high CHEK1 expression was associated with poor outcomes. Increased CHEK1 expression induced MM cellular proliferation and evoked drug-resistance in vitro and in vivo. CHEK1-mediated increases in cell proliferation and drug resistance were due in part to CHEK1-induced CIN. CHEK1 activated CIN, partly by phosphorylating CEP170. Interestingly, CHEK1 promoted osteoclast differentiation by upregulating NFATc1 expression. Intriguingly, we discovered that MM cells expressed circCHEK1_246aa, a circular CHEK1 RNA, which encoded and was translated to the CHEK1 kinase catalytic center. Transfection of circCHEK1_246aa increased MM CIN and osteoclast differentiation similarly to CHEK1 overexpression, suggesting that MM cells could secrete circCHEK1_246aa in the BM niche to increase the invasive potential of MM cells and promote osteoclast differentiation. Conclusions Our findings suggest that targeting the enzymatic catalytic center encoded by CHEK1 mRNA and circCHEK1_246aa is a promising therapeutic modality to target both MM cells and BM niche.

Hypoxia Induces Up-Regulation Of P-Glycoprotein and Promotes Resistance To Carfilzomib In Multiple Myeloma

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4907-4907
Author(s):  
Joseph Abraham ◽  
Salama N Noha ◽  
Abdel Kareem Azab
Keyword(s):  
Multiple Myeloma ◽  
Drug Resistance ◽  
Plasma Cells ◽  
Conflicts Of Interest ◽  
Tumor Hypoxia ◽  
Hematologic Malignancies ◽  
Multi Drug Resistance ◽  
Resistance Proteins ◽  
Hypoxic Conditions ◽  
Bm Niche

Abstract Introduction Multiple myeloma (MM) is a malignant neoplastic cancer of plasma cells that involves the bone marrow. Generally, patients will respond to treatment initially, but they later become resistant to therapy, and this is ultimately due to a change in the biology of the tumor. Multi-drug-resistance transporter proteins were shown to play a role in drug resistance in MM patients; P-glyco-protein (P-gp) is the most studied of the multi-drug resistance proteins, and it becomes up-regulated in response to many chemotheries. Hypoxia was shown to develop in the BM niche during progression of MM and to play a major role in the dissemination of MM cells to the new BM niches. Tumor-hypoxia was shown todevelop many kinds of solid tumors and hematologic malignancies. Specifically, hypoxia was shown to develop in the BM niche during progression of MM and to play a major role in the dissemination of MM cells to the new BM niches. In this study, we examinned the effect of hypoxia on the expression and activity of P-gp in MM and its contributing to drug resistance to therapies used in MM. Methods and Results We tested the effect of hypoxia on the activity of P-gp in MM lines. We incubated MM cells under hypoxic and normoxic conditions, and we tested their ability to pump out Rhodamine (Rh) by measuring Rh content in the cells by fluorescent reader. First, we optimized the concentration of Rh and the time of incubation with the cells. We found that at all concentrations tested (0.1, 0.5, 1, 5 and 10 ug/ml) and at all incubation time of cells with Rh with MM cells (0.25, 0.5, 1, 2, 4, 6, 8 and 24hrs) , hypoxia increased the efflux of Rh. The most significant efflux was achieved when incubating the cells for 1hr with Rh 1ug/ml. We found that hypoxia increased the efflux of Rh in all MM cell lines tested. Incubation of RPMI cells under hypoxic for 24hrs and 48hrs decreased the Rh content of the cells by about 40% and 65%, respectively. Carfilzomib was previously reported to be a substrate of P-gp, we tested the effect of carfilzomib on the efflux of Rd in the MM cells. Hypoxic and normoxic MM cells were treated for 5hrs with carfilzomib (5 nM) and then incubated for 1hrs with Rh (1ug/ml). We tested the Rh content of the cells by fluorescent reader and found that carfilzomib competed with Rh on the P-gp and decreased the efflux of Rh induced by hypoxic. We tested the effect of carfilzomib on induction of P-gp in hypoxic and normoxic MM cells by treating RPMI cells with a low dose of carfilzomib (0.25nM) for 48hrs under hypoxic or normoxic conditions, and tested the cells ability to efflux Rh. We found that carfilzomib increased P-gp expression and induced efflux of about 30% of the Rh in non-treated normoxic cells.  Hypoxia induced efflux of about 65% of normoxic cells, but no effect was observed with the treatment of carfilzomib. Furthermore, we tested the hypoxia-induced P-gp expression in MM on the sensitivity of MM cells to carfilzomib. We incubated MM cells for 24hrs in hypoxic and normoxic conditions, and cells were treated with carfilzomib (0 or 5nM) for additional 24hrs. We found that while carfilzomib induced the death of about 40% of the cells under normoxic condition, it had no significant effect on the survival of MM cell under hypoxic conditions. Conclusion Hypoxia induced a significant up-regulation of P-gp in MM cells, and increased MM drug resistance to carfilzomib. These results provide mechanistic evidence for drug resistance to carfilzomib in MM, and suggest hypoxia as a novel therapeutic to prevent upregulation of P-gp and drug resistance. Disclosures: No relevant conflicts of interest to declare.

RFWD2 Induces Cellular Proliferation and Proteasome Inhibitor Resistance By Mediating p27 Ubiqutinaiton in Multiple Myeloma

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3068-3068
Author(s):  
Ye Yang ◽  
Mengjie Guo ◽  
Chunyan Gu
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Drug Resistance ◽  
Proteasome Inhibitor ◽  
Cellular Proliferation ◽  
Conflicts Of Interest ◽  
Scid Mice ◽  
Rpmi 8226

Purpose: In recent years, with the emergence of targeted proteasome inhibitors (PIs), the treatment of multiple myeloma (MM) has made great progress and significantly improves the survival rate of patients. However, MM remains an incurable disease, mainly due to the recurrence of drug resistance. The constitutive photomorphogenic 1 (RFWD2, also known as COP1), is closely related to the occurrence and development of tumors, but its role in MM is largely unknown. This study was aimed to explore the mechanism of RFWD2 on cell proliferation and resistance to proteasome inhibitor in MM. Experimental Design: Using gene expression profiling (GEP) samples, we verified the relation of RFWD2 to MM patients' survival and drug-resistance. The effect of RFWD2 on cell proliferation was confirmed by MTT and cell cycle analysis in RFWD2-overexpressed and RFWD2-knockdown MM cells. MTT and apoptosis experiments were performed to evaluate whether RFWD2 influenced the sensitivity of MM cells to several chemotherapy drugs. MM xenografts were established in immunodeficient NOD/SCID mice by injecting wild-type or RFWD2 over-expression MM cells with drug intervention. The mechanism of drug resistance was elucidated by analyzing the association of RFWD2 with E3 ligase of p27. Bortezomib-resistant RPMI 8226 cells were used to construct RFWD2 knockdown cells, which were injected into NOD/SCID mice to assess the effect of RFWD2 on bortezomib resistance in vivo. Results: RFWD2 expression was closely related to poor outcome, relapse and bortezomib resistance in MM patients' GEP cohorts. Elevated RFWD2 induced cell proliferation, while decreased RFWD2 inhibited cell proliferation and induced apoptosis in MM cells. RFWD2-overexpression MM cells resulted in PIs resistance, however, no chemotherapy resistance to adriamycin and dexamethasone was observed in vitro. In addition, overexpressing RFWD2 in MM cells led to bortezomib resistance rather than adriamycin resistance in myeloma xenograft mouse model. RFWD2 regulated the ubiquitination degradation of P27 by interacting with RCHY1 ubiquitin ligase. The knockdown of RFWD2 in bortezomib-resistant RPMI 8226 cells overcame bortezomib resistance in vivo. Conclusions: Our data demonstrate that elevated RFWD2 induces MM cell proliferation and resistance to PIs, but not to adriamycin and dexamethasone both in vitro and in vivo through mediating the ubiquitination of p27. Collectively, RFWD2 is a novel promising therapeutic target in MM. Disclosures No relevant conflicts of interest to declare.

scholarly journals BUB1B and circBUB1B_544aa aggravate multiple myeloma malignancy through evoking chromosomal instability

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xiaozhu Tang ◽  
Mengjie guo ◽  
Pinggang Ding ◽  
Zhendong Deng ◽  
Mengying Ke ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Drug Resistance ◽  
Cellular Proliferation ◽  
Chromosome Instability ◽  
Circular Rna ◽  
Catalytic Center ◽  
Poor Outcomes ◽  
Genetic Targeting

AbstractMultiple myeloma (MM) is an incurable plasma cell malignancy in the bone marrow characterized by chromosome instability (CIN), which contributes to the acquisition of heterogeneity, along with MM progression, drug resistance, and relapse. In this study, we elucidated that the expression of BUB1B increased strikingly in MM patients and was closely correlated with poor outcomes. Overexpression of BUB1B facilitated cellular proliferation and induced drug resistance in vitro and in vivo, while genetic targeting BUB1B abrogated this effect. Mechanistic studies unveiled that enforced expression of BUB1B evoked CIN resulting in MM poor outcomes mainly through phosphorylating CEP170. Interestingly, we discovered the existence of circBUB1B_544aa containing the kinase catalytic center of BUB1B, which was translated by a circular RNA of BUB1B. The circBUB1B_544aa elevated in MM peripheral blood samples was closely associated with MM poor outcomes and played a synergistic effect with BUB1B on evoking CIN. In addition, MM cells could secrete circBUB1B_544aa and interfere the MM microenvironmental cells in the same manner as BUB1B full-length protein. Intriguingly, BUB1B siRNA, targeting the kinase catalytic center of both BUB1B and circBUB1B_544aa, significantly inhibited MM malignancy in vitro and in vivo. Collectively, BUB1B and circBUB1B_544aa are promising prognostic and therapeutic targets of MM.

scholarly journals The Emerging Role of Extracellular Vesicle-Associated RNAs in the Multiple Myeloma Microenvironment

2021 ◽  
Vol 11 ◽  
Author(s):  
Jihane Khalife ◽  
James F. Sanchez ◽  
Flavia Pichiorri
Keyword(s):  
Multiple Myeloma ◽  
Drug Resistance ◽  
Plasma Cells ◽  
Immune Surveillance ◽  
Cell Types ◽  
Extracellular Vesicle ◽  
Promising Tool ◽  
Clinical Biomarkers ◽  
Bm Niche ◽  
Prognosis And Prediction

Multiple myeloma (MM) is a cancer of terminally differentiated plasma cells (PCs) that develop at multiple sites within the bone marrow (BM). MM is treatable but rarely curable because of the frequent emergence of drug resistance and relapse. Increasing evidence indicates that the BM microenvironment plays a major role in supporting MM-PC survival and resistance to therapy. The BM microenvironment is a complex milieu containing hematopoietic cells, stromal cells, endothelial cells, immune cells, osteoclasts and osteoblasts, all contributing to the pathobiology of MM, including PC proliferation, escape from immune surveillance, angiogenesis and bone disease development. Small extracellular vesicles (EVs) are heterogenous lipid structures released by all cell types and mediate local and distal cellular communication. In MM, EVs are key mediators of the cross-talk between PCs and the surrounding microenvironment because of their ability to deliver bioactive cargo molecules such as lipids, mRNAs, non-coding regulatory RNA and proteins. Hence, MM-EVs highly contribute to establish a tumor-supportive BM niche that impacts MM pathogenesis and disease progression. In this review, we will first highlight the effects of RNA-containing, MM-derived EVs on the several cellular compartments within the BM microenvironment that play a role in the different aspects of MM pathology. We will also touch on the prospective use of MM-EV-associated non-coding RNAs as clinical biomarkers in the context of “liquid biopsy” in light of their importance as a promising tool in MM diagnosis, prognosis and prediction of drug resistance.

Acyl-CoA Synthetase Long Chain Family Inhibition with Triacsin C Inhibits Multiple Myeloma Cell Proliferation and Survival

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 10-11
Author(s):  
Connor S Murphy ◽  
Heather Fairfield ◽  
Mariah Farrell ◽  
Victoria DeMambro ◽  
Samantha Costa ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Drug Resistance ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
Plasma Cells ◽  
Triacsin C ◽  
Long Chain

Multiple myeloma (MM) is defined by the clonal expansion of malignant plasma cells in the bone marrow (BM) and has a 5-year survival rate of 50% (Siegel el al. 2018, Cancer J. Clin.). MM remains incurable due to the development of resistance to current chemotherapies; therefore, it is paramount to investigate novel treatments and the mechanisms of drug resistance in MM cells. Interestingly, obesity correlates with increased incidence of MM and high body mass index correlates with a poor treatment response (Marinac et al. 2019, JNCI Cancer Spectr, Groß et al. 2017, Oncotarget). Obesity is a major risk factor for many cancers, however, given the complexity of obesity, there are an array of mechanisms by which obesity may support tumor cells. Studies of obesity and MM are mainly at the epidemiological level and have not extensively explored the mechanism of this relationship. Therefore, there is a critical need to understand how obesity contributes to support cancers such as MM. Possible mechanisms may be through the increased availability of free fatty acids or through other factors that are found in obese patients. We hypothesize that lipid metabolism contributes to obesity-linked cancers such as MM. Recently, changes in lipid metabolism have been shown to support the proliferation, migration and the development of drug resistance in other blood cancers such as acute myeloid leukemia (Tabe et al. 2017, Cancer Res, Tabe et al. 2018, Sci. Reports) and solid tumors such as breast (Wang et al. 2017, JCI Insights) and prostate (Mitra et al. 2017, BMC Cancer) cancer. However, the role of lipid metabolism in MM cells has been understudied. Therefore, we hypothesized that genes within the Hallmark Fatty Acid Metabolism gene set (https://www.gsea-msigdb.org) would be differentially expressed between healthy patients and those with MM. We mined the clinical data (GSE6477, Chng et al. 2007, Cancer Res.) and found that transcripts of an enzyme critical for lipid metabolism, acyl-CoA synthetase long chain member 1 (ACSL1), was significantly downregulated (Figure 1A, Log2(Fold Change)=-2.33, adjusted p value=1.64*10-5, false discovery rate) in patients with newly diagnosed MM relative to normal plasma cells. Therefore, we hypothesized that ACSL1 may act as a tumor suppressor in MM. In order to test the role of the ACSL family as tumor suppressors, we treated human (MM1.S, OPM2 and RPMI-8226) and mouse myeloma (5TGM1) cell lines with an inhibitor (Triacsin C, TriC) of four of the five human acyl-CoA synthetase long chain family members (ACSL1,3,4 and 5). Contrary to our hypothesis, TriC treatment significantly decreased MM cell proliferation (Figure 1B, p<0.0001, One-way ANOVA Tukey's multiple comparisons test is used throughout unless otherwise noted), increased apoptosis (Figure 1C, p<0.001) and caused G0 arrest (Figure1D, p<0.0001) in a dose-dependent manner. Motivated to understand if TriC's toxicity was due to changes in metabolic dynamics, MM1.S cells were treated with 1 μM TriC for 30 minutes and subjected to a metabolic flux assay (Seahorse XF, Agilent). TriC treatment significantly reduced ATP-dependent respiration from fatty acid oxidation (FAO) (Figure 1F, p<0.0001 Student's t-test) and increased proton leak (p<0.0001). Taken together, our data demonstrate that TriC-mediated ACSL inhibition in MM cells decreases proliferation, induces G0 arrest, apoptosis and decreases FAO-dependent respiration and mitochondrial function. It is unclear what ACSL family member is responsible for the phenotype we report here. To address these questions, future studies will focus on genetically targeting individual ACSL family members and characterizing the lipidomic profile of MM ACSL mutants. Our data also suggests that fatty acids are used as an energy source, therefore we will explore how FAO contributes to MM cell proliferation and survival. Disclosures No relevant conflicts of interest to declare.

scholarly journals HNRNPA2B1 promotes multiple myeloma progression by increasing AKT3 expression via m6A-dependent stabilization of ILF3 mRNA

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fengjie Jiang ◽  
Xiaozhu Tang ◽  
Chao Tang ◽  
Zhen Hua ◽  
Mengying Ke ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Cellular Proliferation ◽  
Aberrant Expression ◽  
The Stability ◽  
Induced Apoptosis ◽  
Proliferation In Vitro

AbstractN6-methyladenosine (m6A) modification is the most prevalent modification in eukaryotic RNAs while accumulating studies suggest that m6A aberrant expression plays an important role in cancer. HNRNPA2B1 is a m6A reader which binds to nascent RNA and thus affects a perplexing array of RNA metabolism exquisitely. Despite unveiled facets that HNRNPA2B1 is deregulated in several tumors and facilitates tumor growth, a clear role of HNRNPA2B1 in multiple myeloma (MM) remains elusive. Herein, we analyzed the function and the regulatory mechanism of HNRNPA2B1 in MM. We found that HNRNPA2B1 was elevated in MM patients and negatively correlated with favorable prognosis. The depletion of HNRNPA2B1 in MM cells inhibited cell proliferation and induced apoptosis. On the contrary, the overexpression of HNRNPA2B1 promoted cell proliferation in vitro and in vivo. Mechanistic studies revealed that HNRNPA2B1 recognized the m6A sites of ILF3 and enhanced the stability of ILF3 mRNA transcripts, while AKT3 downregulation by siRNA abrogated the cellular proliferation induced by HNRNPA2B1 overexpression. Additionally, the expression of HNRNPA2B1, ILF3 and AKT3 was positively associated with each other in MM tissues tested by immunohistochemistry. In summary, our study highlights that HNRNPA2B1 potentially acts as a therapeutic target of MM through regulating AKT3 expression mediated by ILF3-dependent pattern.

scholarly journals "Intermediate" Cell Types and Mixed Cell Proliferation in Multiple Myeloma: Electron Microscopic Observations

Blood ◽  
1966 ◽  
Vol 27 (2) ◽  
pp. 212-226 ◽  
Author(s):  
JORGE E. MALDONADO ◽  
ROBERT A. KYLE ◽  
ARNOLD L. BROWN ◽  
EDWIN D. BAYRD
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Plasma Cells ◽  
Cell Transformation ◽  
Cell Types ◽  
Lymphoid Cells ◽  
Intermediate Cell ◽  
Electron Microscopic ◽  
Mixed Cell ◽  
Reticulum Cells

Abstract Bone marrow studies of multiple myeloma revealed, in some cases, a conspicuous proliferation of "lymphoid" cells, virtually indistinguishable by light microscopy from those seen in lympho-proliferative disorders. Electron microscopy demonstrated a variety of cells ranging from typical lymphocytes to cells with plasmocytoid features. Between these two types of elements there were cells with intermediate characteristics. In addition, in several cases of myeloma the presence of fixed reticuloendothelial cells and "reticular" plasma cells (or reticulum cells with plasmocytic features) was frequently noted. The presence of reticulum cells and lymphocytes and of cells apparently "intermediate" between these cellular elements and plasma cells, as judged from electron microscopic observations, is suggestive morphologic evidence of a phenomenon of cell transformation and evidence of a mixed cell proliferation in certain cases of multiple myeloma.

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