Multiple myeloma cells alter the senescence phenotype of bone marrow mesenchymal stromal cells under participation of the DLK1-DIO3 genomic region

RAB22A as a predictor of exosome secretion in the progression and relapse of multiple myeloma

BACKGROUND

Multiple myeloma (MM) is an incurable malignant plasma cell disease. We explored the role of RAB22A in exosome secretion, epithelial-mesenchymal transition (EMT) and immune regulation.

METHODS

We obtained MM samples from Gene Expression Omnibus (GEO) data sets. We downloaded the "IOBR" package, and used the "PCA" and "ssGSEA" algorithms to calculate the EMT scores and exosome scores. The "CIBERSORT" package was used to analyze the infiltration of immune cells. We extracted the exosomes of mesenchymal stem cell (MSC) to verify the biological function of RAB22A.

RESULTS

The expression level of RAB22A in smoldering multiple myeloma (SMM) and MM patients was significantly higher than that in normal people and monoclonal gammopathy of undetermined significance (MGUS) patients, and the expression level of RAB22A in relapse MM patients was significantly higher than that in newly diagnosed patients. The EMT scores and exosome scores of high RAB22A group were significantly higher than those of low RAB22A group, and the exosome scores of MSC in recurrent patients were significantly higher than those of newly diagnosed patients. In addition, the infiltration levels of monocyte, NK cells resting, eosinophils, T cells regulatory and T cells CD4 memory activated were positively correlated with RAB22A. After down-regulating the expression of RAB22A in MM-MSC, the secretion of exosomes decreased. Compared with the exosomes of MSC in si-RAB22A group, the exosomes in control group significantly promoted the proliferation of MM.

CONCLUSIONS

RAB22A is a potential therapeutic target to improve the prognosis of MM, which is closely related to exosome secretion, EMT and immune cell infiltration.

Age-related changes in human bone marrow mesenchymal stromal cells: morphology, gene expression profile, immunomodulatory activity and miRNA expression

Introduction

Mesenchymal stromal cells (MSC) are one of the main cellular components of bone marrow (BM) microenvironment. MSC play a key role in tissue regeneration, but they are also capable of immunomodulating activity. With host aging, MSC undergo age-related changes, which alter these functions, contributing to the set-up of "inflammaging", which is known to be the basis for the development of several diseases of the elderly, including cancer. However, there's few data investigating this facet of MSC, mainly obtained using murine models or replicative senescence. The aim of this research was to identify morphological, molecular and functional alterations of human bone marrow-derived MSC from young (yBM-MSC) and old (oBM-MSC) healthy donors.

Methods

MSC were identified by analysis of cell-surface markers according to the ISCT criteria. To evaluate response to inflammatory status, MSC were incubated for 24h in the presence of IL-1β, IFN-α, IFN-ɣ and TNF-α. Macrophages were obtained by differentiation of THP-1 cells through PMA exposure. For M1 polarization experiments, a 24h incubation with LPS and IFN-ɣ was performed. MSC were plated at the bottom of the co-culture transwell system for all the time of cytokine exposure. Gene expression was evaluated by real-time PCR after RNA extraction from BM-MSC or THP-1 culture. Secreted cytokines levels were quantitated through ELISA assays.

Results

Aging MSC display changes in size, morphology and granularity. Higher levels of β-Gal, reactive oxygen species (ROS), IL-6 and IL-8 and impaired colony-forming and cell cycle progression abilities were found in oBM-MSC. Gene expression profile seems to vary according to subjects' age and particularly in oBM-MSC seem to be characterized by an impaired immunomodulating activity, with a reduced inhibition of macrophage M1 status. The comparative analysis of microRNA (miRNA) expression in yBM-MSC and oBM-MSC revealed a significant difference for miRNA known to be involved in macrophage polarization and particularly miR-193b-3p expression is strongly increased after co-culture of macrophages with yBM-MSC.

Conclusion

There are profound differences in terms of morphology, gene and miRNA expression and immunomodulating properties among yBM-MSC and oBM-MSC, supporting the critical role of aging BM microenvironment on senescence, immune-mediated disorders and cancer pathogenesis.

Dysregulation of Non-Coding RNAs: Roles of miRNAs and lncRNAs in the Pathogenesis of Multiple Myeloma

The dysregulation of non-coding RNAs (ncRNAs), specifically microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), leads to the development and advancement of multiple myeloma (MM). miRNAs, in particular, are paramount in post-transcriptional gene regulation, promoting mRNA degradation and translational inhibition. As a result, miRNAs can serve as oncogenes or tumor suppressors depending on the target genes. In MM, miRNA disruption could result in abnormal gene expression responsible for cell growth, apoptosis, and other biological processes pertinent to cancer development. The dysregulated miRNAs inhibit the activity of tumor suppressor genes, contributing to disease progression. Nonetheless, several miRNAs are downregulated in MM and have been identified as gene regulators implicated in extracellular matrix remodeling and cell adhesion. miRNA depletion potentially facilitates the tumor advancement and resistance of therapeutic drugs. Additionally, lncRNAs are key regulators of numerous cellular processes, such as gene expression, chromatin remodeling, protein trafficking, and recently linked MM development. The lncRNAs are uniquely expressed and influence gene expression that supports MM growth, in addition to facilitating cellular proliferation and viability via multiple molecular pathways. miRNA and lncRNA alterations potentially result in anomalous gene expression and interfere with the regular functioning of MM. Thus, this review aims to highlight the dysregulation of these ncRNAs, which engender novel therapeutic modalities for the treatment of MM.

Decoding the role of miRNAs in multiple myeloma pathogenesis: A focus on signaling pathways

Multiple myeloma (MM) is a cancer of plasma cells that has been extensively studied in recent years, with researchers increasingly focusing on the role of microRNAs (miRNAs) in regulating gene expression in MM. Several non-coding RNAs have been demonstrated to regulate MM pathogenesis signaling pathways. These pathways might regulate MM development, apoptosis, progression, and therapeutic outcomes. They are Wnt/β-catenin, PI3K/Akt/mTOR, P53 and KRAS. This review highlights the impending role of miRNAs in MM signaling and their relationship with MM therapeutic interventions.

Communication between bone marrow mesenchymal stem cells and multiple myeloma cells: Impact on disease progression

Multiple myeloma (MM) is a hematological malignancy characterized by the accumulation of immunoglobulin-secreting clonal plasma cells at the bone marrow (BM). The interaction between MM cells and the BM microenvironment, and specifically BM mesenchymal stem cells (BM-MSCs), has a key role in the pathophysiology of this disease. Multiple data support the idea that BM-MSCs not only enhance the proliferation and survival of MM cells but are also involved in the resistance of MM cells to certain drugs, aiding the progression of this hematological tumor. The relation of MM cells with the resident BM-MSCs is a two-way interaction. MM modulate the behavior of BM-MSCs altering their expression profile, proliferation rate, osteogenic potential, and expression of senescence markers. In turn, modified BM-MSCs can produce a set of cytokines that would modulate the BM microenvironment to favor disease progression. The interaction between MM cells and BM-MSCs can be mediated by the secretion of a variety of soluble factors and extracellular vesicles carrying microRNAs, long non-coding RNAs or other molecules. However, the communication between these two types of cells could also involve a direct physical interaction through adhesion molecules or tunneling nanotubes. Thus, understanding the way this communication works and developing strategies to interfere in the process, would preclude the expansion of the MM cells and might offer alternative treatments for this incurable disease.

Mesenchymal stromal cell senescence in haematological malignancies

Acute myeloid leukaemia (AML), chronic lymphocytic leukaemia (CLL), and multiple myeloma (MM) are age-related haematological malignancies with defined precursor states termed myelodysplastic syndrome (MDS), monoclonal B-cell lymphocytosis (MBL), and monoclonal gammopathy of undetermined significance (MGUS), respectively. While the progression from asymptomatic precursor states to malignancy is widely considered to be mediated by the accumulation of genetic mutations in neoplastic haematopoietic cell clones, recent studies suggest that intrinsic genetic changes, alone, may be insufficient to drive the progression to overt malignancy. Notably, studies suggest that extrinsic, microenvironmental changes in the bone marrow (BM) may also promote the transition from these precursor states to active disease. There is now enhanced focus on extrinsic, age-related changes in the BM microenvironment that accompany the development of AML, CLL, and MM. One of the most prominent changes associated with ageing is the accumulation of senescent mesenchymal stromal cells within tissues and organs. In comparison with proliferating cells, senescent cells display an altered profile of secreted factors (secretome), termed the senescence-associated-secretory phenotype (SASP), comprising proteases, inflammatory cytokines, and growth factors that may render the local microenvironment favourable for cancer growth. It is well established that BM mesenchymal stromal cells (BM-MSCs) are key regulators of haematopoietic stem cell maintenance and fate determination. Moreover, there is emerging evidence that BM-MSC senescence may contribute to age-related haematopoietic decline and cancer development. This review explores the association between BM-MSC senescence and the development of haematological malignancies, and the functional role of senescent BM-MSCs in the development of these cancers.

Molecular Features of the Mesenchymal and Osteoblastic Cells in Multiple Myeloma

Multiple myeloma (MM) is a monoclonal gammopathy characterized by biological heterogeneity and unregulated proliferation of plasma cells (PCs) in bone marrow (BM). MM is a multistep process based on genomic instability, epigenetic dysregulation and a tight cross-talk with the BM microenvironment that plays a pivotal role supporting the proliferation, survival, drug-resistance and homing of PCs. The BM microenvironment consists of a hematopoietic and a non-hematopoietic compartment, which cooperate to create a tumor environment. Among the non-hematopoietic component, mesenchymal stromal cells (MSCs) and osteoblasts (OBs) appear transcriptionally and functionally different in MM patients compared to healthy donors (HDs) and to patients with pre-malignant monoclonal gammopathies. Alterations of both MSCs and OBs underly the osteolytic lesions that characterize myeloma-associated bone disease. In this review, we will discuss the different characteristics of MSCs and OBs in MM patients, analyzing the transcriptome, the deregulated molecular pathways and the role performed by miRNAs and exosome in the pathophysiology of MM.

The Role of Cluster C19MC in Pre-Eclampsia Development

Pre-eclampsia is a placenta-related complication occurring in 2-10% of all pregnancies. miRNAs are a group of non-coding RNAs regulating gene expression. There is evidence that C19MC miRNAs are involved in the development of the placenta. Deregulation of chromosome 19 microRNA cluster (C19MC) miRNAs expression leads to impaired cell differentiation, abnormal trophoblast invasion and pathological angiogenesis, which can lead to the development of pre-eclampsia. Information was obtained through a review of articles available in PubMed Medline. Articles on the role of the C19MC miRNA in the development of pre-eclampsia published in 2009-2022 were analyzed. This review article summarizes the current data on the role of the C19MC miRNA in the development of pre-eclampsia. They indicate a significant increase in the expression of most C19MC miRNAs in placental tissue and a high level of circulating fractions in serum and plasma, both in the first and/or third trimester in women with PE. Only for miR-525-5p, low levels of plasma expression were noted in the first trimester, and in the placenta in the third trimester. The search for molecular factors indicating the development of pre-eclampsia before the onset of clinical symptoms seems to be a promising diagnostic route. Identifying women at risk of developing pre-eclampsia at the pre-symptomatic stage would avoid serious complications in both mothers and fetuses. We believe that miRNAs belonging to cluster C19MC could be promising biomarkers of pre-eclampsia development.

Leukemia-Induced Cellular Senescence and Stemness Alterations in Mesenchymal Stem Cells Are Reversible upon Withdrawal of B-Cell Acute Lymphoblastic Leukemia Cells

Leukemic cell growth in the bone marrow (BM) induces a very stressful condition. Mesenchymal stem cells (MSC), a key component of this BM niche, are affected in several ways with unfavorable consequences on hematopoietic stem cells favoring leukemic cells. These alterations in MSC during B-cell acute lymphoblastic leukemia (B-ALL) have not been fully studied. In this work, we have compared the modifications that occur in an in vitro leukemic niche (LN) with those observed in MSC isolated from B-ALL patients. MSC in this LN niche showed features of a senescence process, i.e., altered morphology, increased senescence-associated β-Galactosidase (SA-βGAL) activity, and upregulation of p53 and p21 (without p16 expression), cell-cycle arrest, reduced clonogenicity, and some moderated changes in stemness properties. Importantly, almost all of these features were found in MSC isolated from B-ALL patients. These alterations rendered B-ALL cells susceptible to the chemotherapeutic agent dexamethasone. The senescent process seems to be transient since when leukemic cells are removed, normal MSC morphology is re-established, SA-βGAL expression is diminished, and MSC are capable of re-entering cell cycle. In addition, few cells showed low γH2AX phosphorylation that was reduced to basal levels upon cultivation. The reversibility of the senescent process in MSC must impinge important biological and clinical significance depending on cell interactions in the bone marrow at different stages of disease progression in B-ALL.

Bone Marrow Mesenchymal Stromal Cells in Multiple Myeloma: Their Role as Active Contributors to Myeloma Progression

Multiple myeloma (MM) is a hematological malignancy of plasma cells that proliferate and accumulate within the bone marrow (BM). Work from many groups has made evident that the complex microenvironment of the BM plays a crucial role in myeloma progression and response to therapeutic agents. Within the cellular components of the BM, we will specifically focus on mesenchymal stromal cells (MSCs), which are known to interact with myeloma cells and the other components of the BM through cell to cell, soluble factors and, as more recently evidenced, through extracellular vesicles. Multiple structural and functional abnormalities have been found when characterizing MSCs derived from myeloma patients (MM-MSCs) and comparing them to those from healthy donors (HD-MSCs). Other studies have identified differences in genomic, mRNA, microRNA, histone modification, and DNA methylation profiles. We discuss these distinctive features shaping MM-MSCs and propose a model for the transition from HD-MSCs to MM-MSCs as a consequence of the interaction with myeloma cells. Finally, we review the contribution of MM-MSCs to several aspects of myeloma pathology, specifically to myeloma growth and survival, drug resistance, dissemination and homing, myeloma bone disease, and the induction of a pro-inflammatory and immunosuppressive microenvironment.

Imprinted Genes and Multiple Sclerosis: What Do We Know?

Multiple sclerosis (MS) is a chronic autoimmune neurodegenerative disease of the central nervous system that arises from interplay between non-genetic and genetic risk factors. The epigenetics functions as a link between these factors, affecting gene expression in response to external influence, and therefore should be extensively studied to improve the knowledge of MS molecular mechanisms. Among others, the epigenetic mechanisms underlie the establishment of parent-of-origin effects that appear as phenotypic differences depending on whether the allele was inherited from the mother or father. The most well described manifestation of parent-of-origin effects is genomic imprinting that causes monoallelic gene expression. It becomes more obvious that disturbances in imprinted genes at the least affecting their expression do occur in MS and may be involved in its pathogenesis. In this review we will focus on the potential role of imprinted genes in MS pathogenesis.

Aging of Bone Marrow Mesenchymal Stromal Cells: Hematopoiesis Disturbances and Potential Role in the Development of Hematologic Cancers

Simple Summary

As for many other cancers, the risk of developing hematologic malignancies increases considerably as people age. In recent years, a growing number of studies have highlighted the influence of the aging microenvironment on hematopoiesis and tumor progression. Mesenchymal stromal cells are a major player in intercellular communication inside the bone marrow microenvironment involved in hematopoiesis support. With aging, their functions may be altered, leading to hematopoiesis disturbances which can lead to hematologic cancers. A good understanding of the mechanisms involved in mesenchymal stem cell aging and the consequences on hematopoiesis and tumor progression is therefore necessary for a better comprehension of hematologic malignancies and for the development of therapeutic approaches.

Abstract

Aging of bone marrow is a complex process that is involved in the development of many diseases, including hematologic cancers. The results obtained in this field of research, year after year, underline the important role of cross-talk between hematopoietic stem cells and their close environment. In bone marrow, mesenchymal stromal cells (MSCs) are a major player in cell-to-cell communication, presenting a wide range of functionalities, sometimes opposite, depending on the environmental conditions. Although these cells are actively studied for their therapeutic properties, their role in tumor progression remains unclear. One of the reasons for this is that the aging of MSCs has a direct impact on their behavior and on hematopoiesis. In addition, tumor progression is accompanied by dynamic remodeling of the bone marrow niche that may interfere with MSC functions. The present review presents the main features of MSC senescence in bone marrow and their implications in hematologic cancer progression.

Current Understanding of Myelomatous Mesenchymal Stromal Cells Extended through Advances in Experimental Methods

Simple Summary

As the amount of information available has grown, now it is known that many types of non-hematopoietic cells, including mesenchymal stem/progenitor cells, mature mesenchymal cells, and endothelial cells, as well as mature hematopoietic cells such as monocytes, macrophages, T-cells, and B-cells, have roles in the pathogenesis of multiple myeloma. This review focuses on the role of mesenchymal cells in the microenvironment of multiple myeloma. We summarize the experimental strategies and current understanding of the biological roles in the pathogenesis of myeloma. Furthermore, we discuss the possible clinical applications targeting mesenchymal cells.

Abstract

Multiple myeloma is an incurable cancer formed by malignant plasma cells. For the proliferation and survival of myeloma cells, as well as the occurrence of the complications, numerous intra- and extra-cellular mechanisms are involved. The interaction of myeloma cells with the microenvironment is known to be one of the most critical mechanisms. A specific microenvironment could affect the progression and growth of tumor cells, as well as drug resistance. Among various microenvironment components, such as hematological and non-hematological cells, and soluble factors (cytokines, chemokines, and extracellular matrix (ECM) proteins), in this review, we focus on the role of mesenchymal cells. We aimed to summarize the experimental strategies used for conducting studies and current understanding of the biological roles in the pathogenesis of myeloma. Furthermore, we discuss the possible clinical applications targeting mesenchymal cells.

ETMR: a tumor entity in its infancy

Embryonal tumor with Multilayered Rosettes (ETMR) is a relatively rare but typically deadly type of brain tumor that occurs mostly in infants. Since the discovery of the characteristic chromosome 19 miRNA cluster (C19MC) amplification a decade ago, the methods for diagnosing this entity have improved and many new insights in the molecular landscape of ETMRs have been acquired. All ETMRs, despite their highly heterogeneous histology, are characterized by specific high expression of the RNA-binding protein LIN28A, which is, therefore, often used as a diagnostic marker for these tumors. ETMRs have few recurrent genetic aberrations, mainly affecting the miRNA pathway and including amplification of C19MC (embryonal tumor with multilayered rosettes, C19MC-altered) and mutually exclusive biallelic DICER1 mutations of which the first hit is typically inherited through the germline (embryonal tumor with multilayered rosettes, DICER1-altered). Identification of downstream pathways affected by the deregulated miRNA machinery has led to several proposed potential therapeutical vulnerabilities including targeting the WNT, SHH, or mTOR pathways, MYCN or chromosomal instability. However, despite those findings, treatment outcomes have only marginally improved, since the initial description of this tumor entity. Many patients do not survive longer than a year after diagnosis and the 5-year overall survival rate is still lower than 30%. Thus, there is an urgent need to translate the new insights in ETMR biology into more effective treatments. Here, we present an overview of clinical and molecular characteristics of ETMRs and the current progress on potential targeted therapies.

Autophagy in endothelial cells regulates their haematopoiesis-supporting ability

Background

Endothelial cells (ECs) function as an instructive platform to support haematopoietic stem cell (HSC) homeostasis. Our recent studies found that impaired bone marrow (BM) ECs are responsible for the defective haematopoiesis in patients with poor graft function (PGF), which is characterised by pancytopenia post-allotransplant. Although activated autophagy was reported to benefit ECs, whether EC autophagy plays a critical role in supporting HSCs and its effect on PGF patients post-allotransplant remain unclear.

Methods

To evaluate whether the autophagy status of ECs modulates their ability to support haematopoiesis, human umbilical vein endothelial cells (HUVECs) and primary BM ECs derived from healthy donors were subjected to knockdown or overexpression of Beclin-1 (an autophagy-related protein). Moreover, BM ECs derived from PGF patients were studied.

Findings

Beclin-1 knockdown significantly reduced the haematopoiesis-supporting ability of ECs by suppressing autophagy, which could be restored by activating autophagy via Beclin-1 upregulation. Moreover, autophagy positively regulated haematopoiesis-related genes in HUVECs. Subsequently, a prospective case-control study demonstrated that defective autophagy reduced Beclin-1 expression and the colony-forming unit (CFU) plating efficiency in BM ECs from PGF patients compared to matched patients with good graft function. Rapamycin, an autophagy activator, quantitatively and functionally improved BM ECs from PGF patients in vitro and enhanced their ability to support HSCs by activating the Beclin-1 pathway.

Interpretation

Our results suggest that the autophagy status of ECs modulates their ability to support haematopoiesis by regulating the Beclin-1 pathway. Defective autophagy in BM ECs may be involved in the pathogenesis of PGF post-allotransplant. Rapamycin provides a promising therapeutic approach for PGF patients.

Funding

Please see funding sources.

Bone Marrow Senescence and the Microenvironment of Hematological Malignancies

Senescence is the irreversible arrest of cell proliferation that has now been shown to play an important role in both health and disease. With increasing age senescent cells accumulate throughout the body, including the bone marrow and this has been associated with a number of age-related pathologies including malignancies. It has been shown that the senescence associated secretory phenotype (SASP) creates a pro-tumoural environment that supports proliferation and survival of malignant cells. Understanding the role of senescent cells in tumor development better may help us to identify new treatment targets to impair tumor survival and reduce treatment resistance. In this review, we will specifically discuss the role of senescence in the aging bone marrow (BM) microenvironment. Many BM disorders are age-related diseases and highly dependent on the BM microenvironment. Despite advances in drug development the prognosis particularly for older patients remains poor and new treatment approaches are needed to improve outcomes for patients. In this review, we will focus on the relationship of senescence and hematological malignancies, how senescence promotes cancer development and how malignant cells induce senescence.

anamiR: integrated analysis of MicroRNA and gene expression profiling

BACKGROUND

With advancements in high-throughput technologies, the cost of obtaining expression profiles of both mRNA and microRNA in the same individual has substantially decreased. Integrated analysis of these profiles can help to elucidate the functional effects of RNA expression in complex diseases, such as cancer. However, fundamental discrepancies are observed in the results from microRNA-mRNA target gene prediction algorithms, and few packages can be used to analyze microRNA and mRNA expression levels simultaneously.

RESULTS

To address these issues, an R package, anamiR, was developed. A total of 10 experimental/prediction databases were integrated. Two analytical functions are provided in anamiR, including the single marker test and functional gene set enrichment analysis, and several parameters can be changed by users. Here we demonstrate the potential application of the anamiR package to 2 publicly available microarray datasets.

CONCLUSION

The anamiR package is effective for an integrated analysis of both RNA and microRNA profiles. By characterizing biological functions and signaling pathways, this package helps identify dysregulated genes/miRNAs from biological and medical experiments. The source code and manual of the anamiR package are freely available at https://bioconductor.org/packages/release/bioc/html/anamiR.html .

Epigenetic-Based Mechanisms of Osteoblast Suppression in Multiple Myeloma Bone Disease

Multiple myeloma (MM) bone disease is characterized by the development of osteolytic lesions, which cause severe complications affecting the morbidity, mortality, and treatment of myeloma patients. Myeloma tumors seeded within the bone microenvironment promote hyperactivation of osteoclasts and suppression of osteoblast differentiation. Because of this prolonged suppression of bone marrow stromal cells’ (BMSCs) differentiation into functioning osteoblasts, bone lesions in patients persist even in the absence of active disease. Current antiresorptive therapy provides insufficient bone anabolic effects to reliably repair MM lesions. It has become widely accepted that myeloma‐exposed BMSCs have an altered phenotype with pro‐inflammatory, immune‐modulatory, anti‐osteogenic, and pro‐adipogenic properties. In this review, we focus on the role of epigenetic‐based modalities in the establishment and maintenance of myeloma‐induced suppression of osteogenic commitment of BMSCs. We will focus on recent studies demonstrating the involvement of chromatin‐modifying enzymes in transcriptional repression of osteogenic genes in MM‐BMSCs. We will further address the epigenetic plasticity in the differentiation commitment of osteoprogenitor cells and assess the involvement of chromatin modifiers in MSC‐lineage switching from osteogenic to adipogenic in the context of the inflammatory myeloma microenvironment. Lastly, we will discuss the potential of employing small molecule epigenetic inhibitors currently used in the MM research as therapeutics and bone anabolic agents in the prevention or repair of osteolytic lesions in MM. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Transcriptome Analysis of Mesenchymal Stem Cells from Multiple Myeloma Patients Reveals Downregulation of Genes Involved in Cell Cycle Progression, Immune Response, and Bone Metabolism

A growing body of evidence suggests a key role of tumor microenvironment, especially for bone marrow mesenchymal stem cells (MSC), in the maintenance and progression of multiple myeloma (MM), through direct and indirect interactions with tumor plasma cells. Thus, this study aimed to investigate the gene expression and functional alterations of MSC from MM patients (MM-MSC) in comparison with their normal counterparts from normal donors (ND-MSC). Gene expression analysis (Affymetrix) was performed in MM-MSC and ND-MSC after in vitro expansion. To validate these findings, some genes were selected to be evaluated by quantitative real time PCR (RT-qPCR), and also functional in vitro analyses were performed. We demonstrated that MM-MSC have a distinct gene expression profile than ND-MSC, with 485 differentially expressed genes (DEG) - 280 upregulated and 205 downregulated. Bioinformatics analyses revealed that the main enriched functions among downregulated DEG were related to cell cycle progression, immune response activation and bone metabolism. Four genes were validated by qPCR - ZNF521 and SEMA3A, which are involved in bone metabolism, and HLA-DRA and CHIRL1, which are implicated in the activation of immune response. Taken together, our results suggest that MM-MSC have constitutive abnormalities that remain present even in the absence of tumors cells. The alterations found in cell cycle progression, immune system activation, and osteoblastogenesis suggest, respectively, that MM-MSC are permanently dependent of tumor cells, might contribute to immune evasion and play an essential role in bone lesions frequently found in MM patients.

Dysregulation of ncRNAs located at the DLK1‑DIO3 imprinted domain: involvement in urological cancers

Genomic imprinting has been found to be involved in human physical development and several diseases. The DLK1-DIO3 imprinted domain is located on human chromosome 14 and contains paternally expressed protein-coding genes (DLK1, RTL1, DIO3) and numerous maternally expressed ncRNA genes (MEG3, MEG8, antisense RTL1, miRNAs, piRNAs, and snoRNAs). Emerging evidence has implicated that dysregulation of the DLK1-DIO3 imprinted domain especially the imprinted ncRNAs is critical for tumor progressions. Multiple miRNAs and lncRNAs have been investigated in urological cancers, of which several are transcribed from this domain. In this review, we present current data about the associated miRNAs, lncRNAs, and piRNAs and the regulation of differentially methylated regions methylation status in the progression of urological cancers and preliminarily propose certain concepts about the potential regulatory networks involved in DLK1-DIO3 imprinted domain.

Mesenchymal stem cells gene signature in high-risk myeloma bone marrow linked to suppression of distinct IGFBP2-expressing small adipocytes

Recent studies suggest that multiple myeloma (MM) induces proliferation and expansion of bone marrow (BM) mesenchymal stem cells (MSCs), but others showed that MM cells induce MSC senescence. To clarify the interaction between MM and MSCs, we exploited our established MSC gene signature to identify gene expression changes in myeloma MSCs and associated functional differences. Single MSCs from patients with MM had changes in expression of genes associated with cellular proliferation and senescence and a higher proportion of senescent cells and lower proliferative potential than those from age-matched healthy donors. Single MSCs from both sources heterogeneously express MSC genes associated with adipogenesis and osteoblastogenesis. We identified the gene encoding insulin-like growth factor-binding protein 2 (IGFBP2), an MSC gene commonly altered in high risk MM, as under-expressed. Morphologically, IGFBP2+ cells are underrepresented in MM BM compared to smouldering MM. Strong IGFBP2 and adiponectin co-expression was detected in a subset of small adipocytes. Co-culturing normal MSCs with myeloma cells suppressed MSC differentiation to adipocytes and osteoblasts, and reduced expression of IGFBP2 and adiponectin. Recombinant IGFBP2 blocked IGF1-mediated myeloma cell growth. Our data demonstrate that myeloma MSCs are less proliferative and that IGFBP2+ small adipocytes are a distinct mesenchymal cell population suppressed by myeloma.

Deregulation of the imprinted DLK1-DIO3 locus ncRNAs is associated with replicative senescence of human adipose-derived stem cells

Background

Human adult adipose-derived stem cells (hADSCs) have become the most promising cell source for regenerative medicine. However the prolonged ex vivo expansion periods required to obtain the necessary therapeutic dose promotes progressive senescence, with the concomitant reduction of their therapeutic potential.

Aim and scope

A better understanding of the determinants of hADSC senescence is needed to improve biosafety while preserving therapeutic efficiency. Here, we investigated the association between deregulation of the imprinted DLK1-DIO3 region and replicative senescence in hADSC cultures.

Methods

We compared hADSC cultures at short (P_S) and prolonged (P_L) passages, both in standard and low [O₂] (21 and 3%, respectively), in relation to replicative senescence. hADSCs were evaluated for expression alterations in the DLK1-DIO3 region on chromosome 14q32, and particularly in its main miRNA cluster.

Results

Comparison of hADSCs cultured at P_L or P_S surprisingly showed a quite significant fraction (69%) of upregulated miRNAs in P_L cultures mapping to the imprinted 14q32 locus, the largest miRNA cluster described in the genome. In agreement, expression of the lncRNA MEG3 (Maternally Expressed 3; Meg3/Gtl2), cultured at 21 and 3% [O₂], was also significantly higher in P_L than in P_S passages. During hADSC replicative senescence the AcK16H4 activating mark was found to be significantly associated with the deregulation of the entire DLK1-DIO3 locus, with a secondary regulatory role for the methylation of DMR regions.

Conclusion

A direct relationship between DLK1-DIO3 deregulation and replicative senescence of hADSCs is reported, involving upregulation of a very significant fraction of its largest miRNA cluster (14q32.31), paralleled by the progressive overexpression of the lncRNA MEG3, which plays a central role in the regulation of Dlk1/Dio3 activation status in mice.

Osteoblast suppression in multiple myeloma bone disease

Multiple myeloma (MM) is the most frequent cancer to involve the skeleton with patients developing osteolytic bone lesions due to hyperactivation of osteoclasts and suppression of BMSCs differentiation into functional osteoblasts. Although new therapies for MM have greatly improved survival, MM remains incurable for most patients. Despite the major advances in current anti-MM and anti-resorptive treatments that can significantly improve osteolytic bone lysis, many bone lesions can persist even after therapeutic remission of active disease. Bone marrow mesenchymal stem cells (BMSCs) from MM patients are phenotypically distinct from their healthy counterparts and the mechanisms associated with the long-term osteogenic suppression are largely unknown. In this review we will highlight recent results of transcriptomic profiling studies that provide new insights into the establishment and maintenance of the persistent pathological alterations in MM-BMSCs that occur in MM. We will we discuss the role of genomic instabilities and senescence in propagating the chronically suppressed state and pro-inflammatory phenotype associated with MM-BMSCs. Lastly we describe the role of epigenetic-based mechanisms in regulating osteogenic gene expression to establish and maintain the pro-longed suppression of MM-BMSC differentiation into functional OBs.

Mesenchymal stem cells in multiple myeloma: a therapeutical tool or target?

Multiple myeloma (MM) is a malignant plasma cell (PC) disorder, characterized by a complex interactive network of tumour cells and the bone marrow (BM) stromal microenvironment, contributing to MM cell survival, proliferation and chemoresistance. Mesenchymal stem cells (MSCs) represent the predominant stem cell population of the bone marrow stroma, capable of differentiating into multiple cell lineages, including fibroblasts, adipocytes, chondrocytes and osteoblasts. MSCs can migrate towards primary tumours and metastatic sites, implying that these cells might modulate tumour growth and metastasis. However, this issue remains controversial and is not well understood. Interestingly, several recent studies have shown functional abnormalities of MM patient-derived MSCs indicating that MSCs are not just by-standers in the BM microenvironment but rather active players in the pathophysiology of this disease. It appears that the complex interaction of MSCs and MM cells is critical for MM development and disease outcome. This review will focus on the current understanding of the biological role of MSCs in MM as well as the potential utility of MSC-based therapies in this malignancy.

Dicer1 downregulation by multiple myeloma cells promotes the senescence and tumor-supporting capacity and decreases the differentiation potential of mesenchymal stem cells

Bone marrow mesenchymal stem cells (BMMSCs) facilitate the growth of multiple myeloma (MM) cells, but the underlying mechanisms remain unclear. This study demonstrates that the senescence of MM-MSCs significantly increased, as evidenced by a decrease in proliferation and increase in the number of cells positive for senescence-associated β-galactosidase activity. Senescent MM-MSCs displayed decreased differentiation potential and increased tumor-supporting capacity. Dicer1 knockdown in the MSCs of healthy controls promoted cellular senescence and tumor-supporting capacity, while decreasing the differentiation capacity. Dicer1 overexpression in MM-MSCs reversed the effects on differentiation and reduced cellular senescence. In addition, decreased expression of the microRNA-17 family was identified as a favorable element responsible for increasing senescence, with the expression of p21 increased in Dicer1 knockdown cells. Furthermore, we observed decreased expression of miR-93 and miR-20a in MM-MSCs, while upregulation of miR-93/miR-20a decreased cellular senescence, as evidenced by the increased p21 expression. Importantly, we found that myeloma cells could induce the senescence of MSCs from healthy controls, as observed from the decreased expression of Dicer1 and miR-93/miR-20a and increased expression of p21. Overall, MM cells downregulate Dicer1 in MSCs, which leads to senescence; in turn, senescent MSCs promote MM cell growth, which most likely contributes to disease progression.

Identity, proliferation capacity, genomic stability and novel senescence markers of mesenchymal stem cells isolated from low volume of human bone marrow

Human bone marrow mesenchymal stem cells (hBM-MSCs) hold promise for treating incurable diseases and repairing of damaged tissues. However, hBM-MSCs face the disadvantages of painful invasive isolation and limited cell numbers. In this study we assessed characteristics of MSCs isolated from residual human bone marrow transplantation material and expanded to clinically relevant numbers at passages 3-4 and 6-7. Results indicated that early passage hBM-MSCs are genomically stable and retain identity and high proliferation capacity. Despite the chromosomal stability, the cells became senescent at late passages, paralleling the slower proliferation, altered morphology and immunophenotype. By qRT-PCR array profiling, we revealed 13 genes and 33 miRNAs significantly differentially expressed in late passage cells, among which 8 genes and 30 miRNAs emerged as potential novel biomarkers of hBM-MSC aging. Functional analysis of genes with altered expression showed strong association with biological processes causing cellular senescence. Altogether, this study revives hBM as convenient source for cellular therapy. Potential novel markers provide new details for better understanding the hBM-MSC senescence mechanisms, contributing to basic science, facilitating the development of cellular therapy quality control, and providing new clues for human disease processes since senescence phenotype of the hematological patient hBM-MSCs only very recently has been revealed.

Expansion induced microRNA changes in bone marrow mesenchymal stromal cells reveals interplay between immune regulation and cell cycle

Mesenchymal stromal cells (MSC) are currently used in many cell based therapies. Prior to use in therapy, extensive expansion is required. We used microarray profiling to investigate expansion induced miRNA and mRNA expression changes of bone marrow MSCs (BM-MSCs) derived from old and young donors. The expression levels of 36 miRNAs were altered in cells derived from the old and respectively 39 miRNAs were altered in cells derived from young donors. Of these, only 12 were differentially expressed in both young and old donor BM-MSCs, and their predicted target mRNAs, were mainly linked to cell proliferation and senescence. Further qPCR verification showed that the expression of miR-1915-3p, miR-1207, miR-3665, and miR-762 correlated with the expansion time at passage 8. Previously described BM-MSC-specific miRNA fingerprints were also detected but these remained unchanged during expansion. Interestingly, members of well-studied miR-17/92 cluster, involved in cell cycle regulation, aging and also development of immune system, were down-regulated specifically in cells from old donors. The role of this cluster in MSC functionality is worth future studies since it links expansion, aging and immune system together.

DLK1-DIO3 imprinted locus deregulation in development, respiratory disease, and cancer

INTRODUCTION

The imprinted DLK1-DIO3 locus at 14q32.1-32.31 holds biological significance in fetal development, whereby imprinting errors are causal to developmental disorders. Emerging evidence has implicated this locus in other diseases including cancer, highlighting the biological parallels between fetal organ and tumour development. Areas covered: Controlled regulation of gene expression from the imprinted DLK1-DIO3 locus at 14q32.1-32.31 is crucial for proper fetal development. Deregulation of locus gene expression due to imprinting errors has been mechanistically linked to the developmental disorders Kagami-Ogata Syndrome and Temple Syndrome. In adult tissues, deregulation of locus genes has been associated with multiple malignancies although the causal genetic mechanisms remain largely uncharacterised. Here, we summarize the genetic mechanisms underlying the developmental disorders that arise as a result of improper locus imprinting and the resulting developmental phenotypes, emphasizing both the coding and noncoding components of the locus. We further highlight biological parallels common to both fetal development and disease, with a specific focus on lung development, respiratory disease, and lung cancer. Expert commentary: Many commonalities between respiratory and developmental defects have emerged with respect to the 14q32 locus, emphasizing the importance of studying the effects of imprinting on gene regulation patterns at this locus in both biological settings.

Telomere length is positively associated with the expression of IL‑6 and MIP‑1α in bone marrow mesenchymal stem cells of multiple myeloma

Potential roles of mesenchymal stem cells (MSCs) in the pathogenesis of multiple myeloma (MM) are largely unknown. In the current study, the authors analyzed telomere length and the expressions of interleukin (IL)-6 and macrophage inflammatory protein (MIP)-1α in MSCs derived from the bone marrow (BM) of MM patients and controls. The current results demonstrated that there was no significant difference in cell surface expression of CD73 and CD90, and the capacity to differentiate into bone tissue were identified between the BM MSCs derived from MM patients and controls. Interestingly, telomere length (TL) and mRNA expressions of IL-6 and MIP-1α were significantly longer or higher in BM MSCs of MM than those of controls. Moreover, TL is positively associated with the expressions of IL-6 and MIP-1α at the mRNA level in BM MSCs of MM. Additionally, IL-6 and MIP-1α expression were significantly upregulated when MSCs from MM patients were cultured in the myeloma associated condition medium. The present study indicated that myeloma-associated elongation of TL of BM MSCs may be a key element contributing to the increased IL-6 and MIP-1α expression, by which MSCs in the tumor microenvironment may facilitate MM and/or MM bone disease development.

The function of miR-519d in cell migration, invasion, and proliferation suggests a role in early placentation

The processes of proliferation, migration, and invasion of extravillous trophoblasts are critical for placental implantation and early development, and directly influence pregnancy outcome. Dysregulation of these processes has been associated with placental dysfunction, implicated in clinical conditions such as preeclampsia and placental accreta. Among diverse microRNA (miRNA) species that are expressed in placental trophoblasts, members of the chromosome 19 miRNA cluster (C19MC) stand out in their nearly exclusive expression in the placenta. Recent research on the function of C19MC miRNAs in normal cell physiology and during tumorigenesis identified one C19MC member, miR-519d, as a regulator of cell migration, invasion, and interaction with the extracellular matrix. In this review, we focus on the function of miR-519d in placental trophoblasts, where miR-519d regulates cell migration and invasion, and its aberrant expression is associated with preeclampsia. In cancer, the function of miR-519d as an oncomiR or a tumor-suppressor is dependent upon the tumor type. Further research on the biological function and regulation of miR-519d may illuminate previously unknown mechanisms that control cell migration and invasion.

The T Cell in Myeloma

An active role for the immune system in controlling the malignant plasma cell clone in myeloma has been postulated for many years. The clinical states of monoclonal gammopathy of undetermined significance, plateau phase disease, and smoldering myeloma all suggest that a significant host-tumor interaction is taking place. The fundamental role of the cytotoxic T cell in tumor elimination and control has been exemplified by the dramatic efficacy of adoptive T-cell therapies in many hemopoietic malignancies. However, tumor-host cross-talk results in suppression of the endogenous cytotoxic T-cell response against the malignant plasma cell. Whereas patients with myeloma do not clinically exhibit a T-cell immunodeficiency state, with, for example, increased mycobacterial infections, a number of abnormalities of T-cell function are evident. The major abnormalities of T cells include clonal expansions and associated immunosenescence, alterations of regulatory T cells/T helper 17 cells (Treg/Th17 ratio) and acquired membrane abnormalities, due to trogocytosis, which result in acquired Treg cells. Dendritic cell dysfunction associated with impaired antigen processing and presentation caused by abnormalities of the bone marrow microenvironment plays an additional role. In this perspective, we examine the T-cell abnormalities in myeloma and postulate that, whereas cytotoxic T cells interacting with the tumor are dysfunctional, residual T cells still function adequately against external pathogens and thus protect patients from the infections normally associated with a generalized T-cell immunodeficiency state. The so-called 3 E's of host-tumor interaction (elimination, equilibrium, and escape) are clearly reflected in the immune landscape and clinical behavior of myeloma.

Global, cancer-specific microRNA cluster hypomethylation was functionally associated with the development of non-B non-C hepatocellular carcinoma

Background

While hepatitis B and C viral infection have been suppressed, non-B non-C hepatocellular carcinoma (NBNC-HCC) is considered to be rising in incidence terms in some developed countries where prevalence of those viral infections among HCC patients had been very high (such as Japan, Korea, and Italy). To elucidate critical molecular changes in NBNC-HCC, we integrated three large datasets relating to comprehensive array-based analysis of genome-wide DNA methylation (N = 43 pairs) and mRNA/miRNA expression (N = 15, and 24 pairs, respectively) via statistical modeling.

Results

Hierarchical clustering of DNA methylation in miRNA coding regions clearly distinguished NBNC-HCC tissue samples from relevant background tissues, revealing a remarkable tumor-specific hypomethylation cluster. In addition, miRNA clusters were extremely hypomethylated in tumor samples (median methylation change for non-clustered miRNAs: -2.3%, clustered miRNAs: -24.6%). The proportion of CpGs hypomethylated in more than 90% of the samples was 55.9% of all CpGs within miRNA clusters, and the peak methylation level was drastically shifted from 84% to 39%. Following statistical adjustment, the difference in methylation levels within miRNA coding regions was positively associated with their expression change. Receiver operating characteristic (ROC) analysis revealed a great discriminatory ability in respect to cluster-miRNA methylation. Moreover, miRNA methylation change was negatively correlated with corresponding target gene expression amongst conserved and highly matched miRNA sites.

Conclusions

We observed a drastic negative shift of methylation levels in miRNA cluster regions. Changes in methylation status of miRNAs were more indicative of target gene expression and pathological diagnosis than respective miRNA expression changes, suggesting the importance of genome-wide miRNA methylation for tumor development. Our study dynamically summarized global miRNA hypomethylation and its genome-wide scale consequence in NBNC-HCC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0514-6) contains supplementary material, which is available to authorized users.

MicroRNAs: Novel Crossroads between Myeloma Cells and the Bone Marrow Microenvironment

Multiple myeloma (MM) is a hematologic malignancy of differentiated plasma cells that accumulate in the bone marrow, where a complex microenvironment made by different cell types supports proliferation, survival, and drug resistance of tumor cells. MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression at posttranscriptional level. Emerging evidence indicates that miRNAs are aberrantly expressed or functionally deregulated in MM cells as the result of multiple genetic or epigenetic mechanisms and that also the tumor microenvironment regulates MM cell functions by miRNAs. Consistently, modulation of miRNA levels in MM cells has been demonstrated to impair their functional interaction with the bone marrow microenvironment and to produce significant antitumor activity even able to overcome the protective bone marrow milieu. This review will describe the most recent findings on miRNA function in the context of MM bone marrow microenvironment, focusing on the therapeutic potential of miRNA-based approaches.

Multiple myeloma cells modify VEGF/IL-6 levels and osteogenic potential of bone marrow stromal cells via Notch/miR-223

Bone marrow mesenchymal stromal cells (BMMSCs) represent a crucial component of multiple myeloma (MM) microenvironment supporting its progression and proliferation. Recently, microRNAs have become an important point of interest for research on micro-environmental interactions in MM with some evidence of tumor supportive roles in MM. In this study, we examined the role of miR-223 for MM support in BMMSCs of 56 patients with MM (MM-BMMSCs). miR-223 expression in MM-BMMSCs was reduced by the presence of MM cells in vitro in a cell-contact dependent manner compared to mono-cultured MM-BMMSCs. Co-cultivation of MM cells and MM-BMMSCs induced activation of notch amongst others via jagged-2/notch-2 leading to increased expression of Hes1, Hey2, or Hes5 in both cell types. Cultivation of MM-BMMSCs with increasing levels of recombinant jagged-2 reduced miR-223 and increased Hes1 levels in a concentration-dependent manner. Transient reduction of miR-223 levels increased VEGF and IL-6 expression and secretion by MM-BMMSCs. In addition, reduction of miR-223 degraded the osteogenic differentiation potential of MM-BMMSCs. Inhibition of notch signaling induced apoptosis in both MM cells and MM-BMMSCs. Furthermore, it increased miR-223 levels and reduced expression of VEGF and IL-6 by both cell types. These data provide first evidence that miR-223 participates in different MM supporting pathways in MM-BMMSCs inlcuding regulation of cytokine secretion and expression as well as osteogenic differentiation of MM-BMMSCs. More insights on the role of miR-223 in MM-BMMSCs and in cellular interactions between MM cells and MM-BMMSCs could provide starting points for a more efficient anti-myeloma treatment by targeting of notch signaling. © 2015 Wiley Periodicals, Inc.