scholarly journals Cx43 expressed on bone marrow stromal cells plays an essential role in multiple myeloma cell survival and drug resistance

2017 ◽  
Vol 1 ◽  
pp. 236-245 ◽  
Author(s):  
Jinxiang Fu
Blood ◽  
2009 ◽  
Vol 113 (18) ◽  
pp. 4309-4318 ◽  
Author(s):  
Yu-Tzu Tai ◽  
Ender Soydan ◽  
Weihua Song ◽  
Mariateresa Fulciniti ◽  
Kihyun Kim ◽  
...  

Abstract CS1 is highly expressed on tumor cells from the majority of multiple myeloma (MM) patients regardless of cytogenetic abnormalities or response to current treatments. Furthermore, CS1 is detected in MM patient sera and correlates with active disease. However, its contribution to MM pathophysiology is undefined. We here show that CS1 knockdown using lentiviral short-interfering RNA decreased phosphorylation of ERK1/2, AKT, and STAT3, suggesting that CS1 induces central growth and survival signaling pathways in MM cells. Serum deprivation markedly blocked survival at earlier time points in CS1 knockdown compared with control MM cells, associated with earlier activation of caspases, poly(ADP-ribose) polymerase, and proapoptotic proteins BNIP3 and BIK. CS1 knockdown further delayed development of MM tumor and prolonged survival in mice. Conversely, CS1 overexpression promoted myeloma cell growth and survival by significantly increasing myeloma adhesion to bone marrow stromal cells (BMSCs) and enhancing myeloma colony formation in semisolid culture. Moreover, CS1 increased c-maf–targeted cyclin D2-dependent proliferation, -integrin β7/αE-mediated myeloma adhesion to BMSCs, and -vascular endothelial growth factor-induced bone marrow angiogenesis in vivo. These studies provide direct evidence of the role of CS1 in myeloma pathogenesis, define molecular mechanisms regulating its effects, and further support novel therapies targeting CS1 in MM.


2019 ◽  
Vol 20 (3) ◽  
pp. 702 ◽  
Author(s):  
Jonathan J. Morgan ◽  
Roisin M. McAvera ◽  
Lisa J. Crawford

The bone marrow (BM) microenvironment plays an important role in supporting proliferation, survival and drug resistance of Multiple Myeloma (MM) cells. MM cells adhere to bone marrow stromal cells leading to the activation of tumour-promoting signaling pathways. Activation of the NFκB pathway, in particular, is central to the pathogenesis of MM. Tumour necrosis factor receptor-associated factor 6 (TRAF6) is a key mediator of NFκB activation and has previously been highlighted as a potential therapeutic target in MM. Here, we demonstrate that adherence of MM cell lines to stromal cells results in a reciprocal increase in TRAF6 expression. Knockdown of TRAF6 expression attenuates the ability of MM cells to bind to stromal cells and this is associated with a decrease in NFκB-induced expression of the adhesion molecules ICAM1 and VCAM1. Finally, we show that knockdown of TRAF6 sensitizes MM cells to treatment with bortezomib when co-cultured with stromal cells. Inhibiting TRAF6 represents a promising strategy to target MM cells in the BM microenvironment.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1772-1772 ◽  
Author(s):  
Jahangir Abdi ◽  
Yijun Yang ◽  
Patrick Meyer-Erlach ◽  
Hong Chang

Abstract INTRODUCTION It is not yet fully understood how bone marrow microenvironment components especially bone marrow stromal cells (BMSCs) induce drug resistance in multiple myeloma (MM). This form of drug resistance has been suggested to pave the way for intrinsic (de novo) resistance to therapy in early stages of the disease and contribute to acquired drug resistance in the course of treatment. Hence, deciphering the molecular mechanisms involved in induction of above resistance will help identify potential therapeutic targets in MM combined treatments. Our previous work showed that BMSCs (normal and MM patient-derived) induced resistance to bortezomib (BTZ) compared with MM cells in the absence of stroma. This resistance was associated with modulation of a transcriptome in MM cells, including prominent upregulation of oncogenes c-FOS, BIRC5 (survivin) and CCND1. However; whether these oncogenes mediate BTZ resistance in the context of BMSCs through interaction with miRNAs is not known. METHODS Human myeloma cell lines, 8226, U266 and MM.1s, were co-cultured with MM patient-derived BMSCs or an immortalized normal human line (HS-5) in the presence of 5nM BTZ for 24 h. MM cell monocultures treated with 5nM BTZ were used as controls. Co-cultures were then applied to magnetic cell separation (EasySep, Stem Cell Technologies) to isolate MM cells for downstream analyses (western blotting and qPCR). Total RNA including miRNAs was isolated from MM cell pellets (QIAGEN miRNeasy kit), cDNAs were synthesized (QIAGEN miScript RT II kit) and applied to miScript miRNA PCR Array (SABioscience, MIHS-114ZA). After normalization of all extracted Ct values to 5 different housekeeping genes, fold changes in miRNA expression were analyzed in co-cultures compared to MM cell monocultures using the 2-ΔΔCt algorithm. Moreover, survivin gene was silenced in MM cells using Ambion® Silencer® Select siRNA and Lipofectamine RNAiMAX transfection reagent. Survivin-silenced cells were then seeded on BMSCs and exposed to BTZ. Percent apoptosis of gated CD138+ MM cells was determined using FACS. For our overexpression and 3'UTR reporter experiments, we transiently transfected MM cells with pre-miR-101-3p, scrambled miRNA or pEZX-3'UTR constructs using Endofectin reagent (all from GeneCopoeia). RESULTS BMSCs upregulated survivin gene / protein (a member of inhibitors of apoptosis family) and modulated an array of miRNAs in MM cells compared to MM cells in the absence of stroma. The more noticeably downregulated miRNAs were hsa-miR-101-3p, hsa-miR-29b-3p, hsa-miR-32-5p, hsa-miR-16-5p (4-30 fold) and highly upregulated ones included hsa-miR-221-3p, hsa-miR-409-3p, hsa-miR-193a-5p, hsa-miR-125a-5p (80-330 fold). We focused on miRNA-101-3p as it showed the highest level of downregulation (30 fold) and has been shown to function as an important tumor suppressor in other malignancies. Real time RT-PCR confirmed downregulation of miRNA-101-3p. Moreover, microRNA Data Integration Portal (mirDIP) identified miRNA-101-3p as a putative target for survivin and Luciferase activity assays confirmed binding of miRNA-101-3p to 3'UTR of survivin. In addition, overexpression of miRNA-101-3p downregulated survivin and sensitized MM cells to BTZ-induced apoptosis. Furthermore, silencing of survivin upregulated miRNA-101-3p and increased BTZ-induced apoptosis in MM cell lines both in the absence of BMSCs (Apoptosis range in BTZ-treated conditions: 57.65% ± 4.91 and 28.66% ± 0.78 for si-survivin and scrambled control, respectively, p<0.05) and in the presence of BMSCs (41.23% ± 1.43 and 14.8% ± 0.66, for si-survivin and scrambled control, respectively, p<0.05). CONCLUSION Our results indicate that BMSCs downregulated miRNA-101-3p and upregulated survivin in MM cells compared to MM cells in the absence of stroma. Silencing of survivin or overexpression of miRNA-101-3p sensitized MM cells to BTZ in the presence of BMSCs. These findings suggest that miRNA-101-3p mediates BTZ response of MM cells in the presence of BMSCs by targeting survivin and disclose a role of survivin-miRNA-101-3p axis in regulation of BMSCs-induced BTZ resistance in MM cells, thus provide a rationale to further investigate the anti-myeloma activity of miRNA-101-3p in combination with BTZ as a potential novel therapeutic strategy in MM. Disclosures No relevant conflicts of interest to declare.


2020 ◽  
Vol 21 (2) ◽  
pp. 613 ◽  
Author(s):  
Roberto Ria ◽  
Angelo Vacca

Multiple myeloma is a B-cell lineage cancer in which neoplastic plasma cells expand in the bone marrow and pathophysiological interactions with components of microenvironment influence many biological aspects of the malignant phenotype, including apoptosis, survival, proliferation, and invasion. Despite the therapeutic progress achieved in the last two decades with the introduction of a more effective and safe new class of drugs (i.e., immunomodulators, proteasome inhibitors, monoclonal antibodies), there is improvement in patient survival, and multiple myeloma (MM) remains a non-curable disease. The bone marrow microenvironment is a complex structure composed of cells, extracellular matrix (ECM) proteins, and cytokines, in which tumor plasma cells home and expand. The role of the bone marrow (BM) microenvironment is fundamental during MM disease progression because modification induced by tumor plasma cells is crucial for composing a “permissive” environment that supports MM plasma cells proliferation, migration, survival, and drug resistance. The “activated phenotype” of the microenvironment of multiple myeloma is functional to plasma cell proliferation and spreading and to plasma cell drug resistance. Plasma cell drug resistance induced by bone marrow stromal cells is mediated by stress-managing pathways, autophagy, transcriptional rewiring, and non-coding RNAs dysregulation. These processes represent novel targets for the ever-increasing anti-MM therapeutic armamentarium.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4804-4804
Author(s):  
Jing Yang ◽  
Yuhuan Zheng ◽  
Zhen Cai ◽  
Jianfei Qian ◽  
Sungyoul Hong ◽  
...  

Abstract Abstract 4804 Multiple myeloma is a B-cell malignancy characterized by the proliferation of plasma cells in the bone marrow. It is the second most common hematological malignancy and is still largely incurable. One of the major problems is that myeloma cells develop drug resistance upon interaction with bone marrow stromal cells. To better understand the importance of different stromal cell components in the bone marrow microenvironment, we examined the effects of macrophages on myeloma cell survival and myeloma cell response to chemotherapy. We report here that macrophages, in particular tumor-associated macrophages obtained by culturing macrophages with myeloma cell culture supernatants, are a protector of myeloma cells. Macrophages protected both myeloma cell lines and primary myeloma cells isolated from patients from spontaneous and chemotherapy drug-induced apoptosis via attenuating the activation of caspase-dependent apoptotic signaling. The protective effect was dependent on direct contact between macrophages and myeloma cells. Although tumor-associated macrophages secreted large amounts of IL-6, which is the most important survival factor for myeloma cells, our results showed that IL-6 neutralizing antibodies fail to significantly affect the protective effects of tumor-associated macrophages. The reduced numbers of apoptotic tumor cells in the cocultures were not the result of macrophage-uptake of apoptotic cells, because macrophages with or without the ability to phagocytose apoptotic cells provide similar protection to myeloma cells against chemotherapy-induced apoptosis. These findings are clinically relevant, because we examined bone marrow biopsies of patients by immunochemical analysis and found that CD68+ macrophages are heavily infiltrated in the bone marrow (tumor bed) of patients with myeloma but not control patients. Thus, our results indicate that macrophages are an important component of the bone marrow stromal cells and may contribute to myeloma cell survival and resistance to chemotherapeutic treatment in vivo. Disclosures: No relevant conflicts of interest to declare.


2011 ◽  
Vol 52 (10) ◽  
pp. 1991-1998 ◽  
Author(s):  
Xudong Wang ◽  
Chang Li ◽  
Shaoqing Ju ◽  
Yueguo Wang ◽  
Huimin Wang ◽  
...  

Blood ◽  
2007 ◽  
Vol 110 (13) ◽  
pp. 4373-4384 ◽  
Author(s):  
Li Hua Wang ◽  
Xiao Yi Yang ◽  
Xiaohu Zhang ◽  
William L. Farrar

Binding of multiple myeloma (MM) cells to bone marrow stromal cells (BMSCs) triggers expression of adhesive molecules and secretion of interleukin-6 (IL-6), promoting MM cell growth, survival, drug resistance, and migration, which highlights the possibility of developing and validating novel anti-MM therapeutic strategies targeting MM cells–host BMSC interactions and their sequelae. Recently, we have found that expression of the peroxisome proliferator-activated receptor γ (PPARγ) and its ligands can potently inhibit IL-6–regulated MM cell growth. Here we demonstrate that PPARγ agonists 15-d-PGJ2 and troglitazone significantly suppress cell-cell adhesive events, including expression of adhesion molecules and IL-6 secretion from BMSCs triggered by adhesion of MM cells, as well as overcome drug resistance by a PPARγ-dependent mechanism. The synthetic and natural PPARγ agonists have diverging and overlapping mechanisms blocking transactivation of transcription factors NF-κB and 5′-CCAAT/enhancer–binding protein β (C/EBPβ). Both 15-d-PGJ2 and troglitazone blocked C/EBPβ transcriptional activity by forming PPARγ complexes with C/EBPβ. 15-d-PGJ2 and troglitazone also blocked NF-κB activation by recruiting the coactivator PGC-1 from p65/p50 complexes. In addition, 15-d-PGJ2 had a non–PPARγ-dependent effect by inactivation of phosphorylation of IKK and IκB. These studies provide the framework for PPARγ-based pharmacological strategies targeting adhesive interactions of MM cells with the bone marrow microenvironment.


2013 ◽  
Vol 18 (6) ◽  
pp. 637-646 ◽  
Author(s):  
Kristine Misund ◽  
Katarzyna A. Baranowska ◽  
Toril Holien ◽  
Christoph Rampa ◽  
Dionne C. G. Klein ◽  
...  

The tumor microenvironment can profoundly affect tumor cell survival as well as alter antitumor drug activity. However, conventional anticancer drug screening typically is performed in the absence of stromal cells. Here, we analyzed survival of myeloma cells co-cultured with bone marrow stromal cells (BMSC) using an automated fluorescence microscope platform, ScanR. By staining the cell nuclei with DRAQ5, we could distinguish between BMSC and myeloma cells, based on their staining intensity and nuclear shape. Using the apoptotic marker YO-PRO-1, the effects of drug treatment on the viability of the myeloma cells in the presence of stromal cells could be measured. The method does not require cell staining before incubation with drugs, and less than 5000 cells are required per condition. The method can be used for large-scale screening of anticancer drugs on primary myeloma cells. This study shows the importance of stromal cell support for primary myeloma cell survival in vitro, as half of the cell samples had a marked increase in their viability when cultured in the presence of BMSC. Stromal cell–induced protection against common myeloma drugs is also observed with this method.


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