Endothelial and cancer cells interact with mesenchymal stem cells via both microparticles and secreted factors

Osteogenic Efficacy of Human Trophoblasts-Derived Conditioned Medium on Mesenchymal Stem Cells

Trophoblasts play an important role in the regulation of the development and function of the placenta. Our recent study demonstrated the skin regeneration capacity of trophoblast-derived extracellular vesicles (EV). Here, we aimed to determine the potential of trophoblast-derived conditioned medium (TB-CM) in enhancing the osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs). We found that TB-CM promoted the osteogenic differentiation of MSCs in a dose-dependent manner. Furthermore, it inhibited adipogenesis of MSCs. We also found that the primary trophoblast-derived conditioned medium (PTB-CM) significantly enhanced the proliferation and osteogenic differentiation of human MSCs. Our study demonstrated the regulatory mechanisms underlying the TB-CM-induced osteogenesis in MSCs. An upregulation of genes associated with cytokines/chemokines was observed. The treatment of MSCs with TB-CM stimulated osteogenesis by activating several biological processes, such as mitogen-activated protein kinase (MAPK) and bone morphogenetic protein 2 (BMP2) signaling. This study demonstrated the proliferative and osteogenic efficacies of the trophoblast-derived secretomes, suggesting their potential for use in clinical interventions for bone regeneration and treatment.

Secretome of Stem Cells: Roles of Extracellular Vesicles in Diseases, Stemness, Differentiation, and Reprogramming

Increasing evidence suggests that stem cells or stem cell-derived cells may contribute to tissue repair, not only by replacing lost tissue but also by delivering complex sets of secretory molecules, called secretomes, into host injured tissues. In recent years, extracellular vesicles (EVs) have gained much attention for their diverse and important roles in a wide range of pathophysiological processes. EVs are released from most types of cells and mediates cell-cell communication by activating receptors on target cells or by being taken up by recipient cells. EVs, including microvesicles and exosomes, encapsulate and carry proteins, nucleic acids, and lipids in the lumen and on the cell surface. Thus, EV-mediated intercellular communication has been extensively studied across various biological processes. While a number of investigations has been conducted in different tissues and body fluids, the field lacks a systematic review on stem cell-derived EVs, especially regarding their roles in stemness and differentiation. Here, we provide an overview of the pathophysiological roles of EVs and summarize recent findings focusing on EVs released from various types of stem cells. We also highlight emerging evidence for the potential implication of EVs in self-renewal, differentiation, and reprograming and discuss the benefits and limitations in translational approaches.

Complex effect of continuous curcumin exposure on human bone marrow-derived mesenchymal stem cell regenerative properties through matrix metalloproteinase regulation

Curcumin has been reported to be beneficial for cancers, cardiovascular and neurodegenerative diseases, based on its anti-oxidative, anti-inflammation, anti-tumorigenic and neuroprotective properties. With its high-dose application, curcumin toxicity to systemic tissues is a reasonable concern. Here, we report the responses of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) to continuous curcumin exposure. hBM-MSCs were treated with 0.01-100 μmol/L curcumin continuously in vitro for 7 days. 25 μmol/L curcumin or above significantly attenuated hBM-MSC maintenance, whereas 10 μmol/L curcumin reduced hBM-MSC proliferation and hindered their migration with increasing cell apoptosis. Besides, 5 μmol/L curcumin treatment inhibited hBM-MSC adipogenic differentiation, but enhanced osteogenic differentiation, which depended on matrix metalloproteinase (MMP)-13 expression and activity. Furthermore, curcumin treatment reduced MMP1 expression but up-regulated the immunomodulatory gene IDO1 expression. In summary, this study revealed the complex effects of continuous curcumin exposure on hBM-MSC maintenance and regenerative properties through MMP regulation. Given the complex effects of curcumin, its use for biomedical purposes should be carefully considered in treatment length and dosage.

Vascular Endothelial Cell-derived Exosomes Protect Neural Stem Cells Against Ischemia/reperfusion Injury

Vascular endothelial cells were activated during acute ischemic brain injury, which could induce neural progenitor cell proliferation and migration. However, the mechanism was still unknown. In the current study, we explored whether vascular endothelial cells promoted neural progenitor cell proliferation and whether migration occurs via exosome communication. The acute middle cerebral artery occlusion (MCAO) model was prepared, and exosomes were isolated from bEnd.3 cells by ultracentrifugation. In the exosome injection (Exos) group and PBS injection (control) group, exosomes or PBS were injected intraventricularly into rats' brains 2 h after MCAO surgery, respectively. Sham group rats received the same surgical but did not cause middle cerebral artery occlusion. The infarct volume was reduced on day 21 after ischemic brain injury by MRI, and neurobehavioral outcomes were improved on day 7, 14, and 21 by exosome injection compared with the control (p < 0.05). On the 21st day after MCAO, the animals were euthanized, and the number of BrdU/nestin-positive cells was measured by immunofluorescence. BrdU/nestin-positive cells in Exos group rats were significantly increased (p < 0.05) in the peri infarct area, the ipsilateral DG zone of the hippocampus, and the ventral sub-regions of SVZ when compared with the rats in the control group. Further, in vitro study demonstrated that neural progenitor cell proliferation and migration were activated after exosomes treatment, and cell apoptosis was attenuated compared to the control (p < 0.05). Our study suggested that exosomes should be essential for the reconstruction of neuronal vascular units and brain protection in an acute ischemic injured brain.

Enhancement of therapeutic potential of mesenchymal stem cell-derived extracellular vesicles

After the initial investigations into applications of mesenchymal stem cells (MSCs) for cell therapy, there was increased interest in their secreted soluble factors. Following studies of MSCs and their secreted factors, extracellular vesicles (EVs) released from MSCs have emerged as a new mode of intercellular crosstalk. MSC-derived EVs have been identified as essential signaling mediators under both physiological and pathological conditions, and they appear to be responsible for many of the therapeutic effects of MSCs. In several in vitro and in vivo models, EVs have been observed to have supportive functions in modulating the immune system, mainly mediated by EV-associated proteins and nucleic acids. Moreover, stimulation of MSCs with biophysical or biochemical cues, including EVs from other cells, has been shown to influence the contents and biological activities of subsequent MSC-derived EVs. This review provides on overview of the contents of MSC-derived EVs in terms of their supportive effects, and it provides different perspectives on the manipulation of MSCs to improve the secretion of EVs and subsequent EV-mediated activities. In this review, we discuss the possibilities for manipulating MSCs for EV-based cell therapy and for using EVs to affect the expression of elements of interest in MSCs. In this way, we provide a clear perspective on the state of the art of EVs in cell therapy focusing on MSCs, and we raise pertinent questions and suggestions for knowledge gaps to be filled.

Microvesicles of osteoblasts modulate bone marrow mesenchymal stem cell-induced apoptosis to curcumin in myeloid leukemia cells

Microvesicles (MVs) derived from bone marrow niche components have an important role in genetic reprogramming and subsequent drugs induce apoptosis in leukemic cells. Here, we have found that undertreatment of curcumin or daunorubicin, the cross-talk through MVs of KG-1-bone marrow mesenchymal stem cells (BMSCs), significantly downregulates the expression of the survival gene osteopontin (OPN), CXCL-12, IL-6 (interleukin-6), STAT-3, and VCAM-1 (vascular cell adhesion molecule 1) in treated-KG-1 cells as well as exclusively upregulates CXCL-12 in BMSCs. Drug treated-cell populations' MVs of both single cultured osteoblasts (OBs) and cocultured KG-1 + BMSCs + OBs similarly upregulate survival mediators' OPN, CXCL-12, IL-6, STAT-3, and VCAM-1 in treated-KG-1 cells. Likewise, isolated MVs from KG-1 cells or communication between KG-1, BMSCs, and OBs treated by drugs increase the expression of genes OPN, CXCL-12, IL-6, STAT3, and VCAM-1 by OBs. MVs derived from KG-1 + BMSCs + OBs reduce drug-induced apoptosis in KG-1 cells. This suggests MVs-mediated information transfer is a procedure whereby OBs could overcome BMSCs-induced apoptosis in drug-treated-KG-1 cells.

Endothelial activation and injury by microparticles in patients with systemic lupus erythematosus and rheumatoid arthritis

BACKGROUND

Endothelial activation and damage is commonly observed in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and is related to development of atherosclerosis and cardiovascular diseases. Different components of the immune system seem to participate in the endothelial injury, such as generation of autoantibodies and formation of immune complexes (ICs). Microparticles (MPs) and their immune complexes (MPs-ICs) are increased in the circulation of patients with SLE and RA; therefore, we propose these extracellular vesicles could interact and modulate the function of endothelial cells. Hence, the effect of MPs and MPs-ICs from patients with SLE and RA in endothelial cells was evaluated.

METHODS

Macrovascular and microvascular endothelial cells were exposed to MPs and MPs-ICs from healthy donors and patients with SLE and RA. Vesicles uptake/binding, expression of adhesion molecules, cytokine and chemokine production, monocyte adherence, and alterations of endothelial monolayer were evaluated by flow cytometry and fluorescence microscopy.

RESULTS

Endothelial cells internalized MPs and MPs-ICs and increased CD54 and CD102 expression and CCL2, CCL5, and IL-6 production after the treatment with these extracellular vesicles, which led to an increase in the adherence of classic monocytes. These vesicles also induced low expression of VE-cadherin in membrane, depolymerization of actin filaments, and formation of intercellular spaces, which led to endothelial death and increased permeability after MPs and MPs-ICs exposure.

CONCLUSIONS

MPs and MPs-ICs from patients with SLE and RA increase adhesion molecules expression, chemokine production, and structural alterations in macrovascular and microvascular endothelial cells. Therefore, high counts of these vesicles in patients would promote endothelial alterations and secondary tissue leukocyte infiltration.

Vascular Stem/Progenitor Cell Migration and Differentiation in Atherosclerosis

SIGNIFICANCE

Atherosclerosis is a major cause for the death of human beings, and it takes place in large- and middle-sized arteries. The pathogenesis of the disease has been widely investigated, and new findings on vascular stem/progenitor cells could have an impact on vascular regeneration. Recent Advances: Recent studies have shown that abundant stem/progenitor cells present in the vessel wall are mainly responsible for cell accumulation in the intima during vascular remodeling. It has been demonstrated that the mobilization and recruitment of tissue-resident stem/progenitor cells give rise to endothelial and smooth muscle cells (SMCs) that participate in vascular repair and remodeling such as neointimal hyperplasia and arteriosclerosis. Interestingly, cell lineage tracing studies indicate that a large proportion of SMCs in neointimal lesions is derived from adventitial stem/progenitor cells.

CRITICAL ISSUES

The influence of stem/progenitor cell behavior on the development of atherosclerosis is crucial. An understanding of the regulatory mechanisms that control stem/progenitor cell migration and differentiation is essential for stem/progenitor cell therapy for vascular diseases and regenerative medicine.

FUTURE DIRECTIONS

Identification of the detailed process driving the migration and differentiation of vascular stem/progenitor cells during the development of atherosclerosis, discovery of the environmental cues, and signaling pathways that control cell fate within the vasculature will facilitate the development of new preventive and therapeutic strategies to combat atherosclerosis. Antioxid. Redox Signal. 00, 000-000.

Extracellular Vesicles: A New Prospective in Crosstalk between Microenvironment and Stem Cells in Hematological Malignancies

The bone marrow (BM) microenvironment in hematological malignancies (HMs) comprises heterogeneous populations of neoplastic and nonneoplastic cells. Cancer stem cells (CSCs), neoplastic cells, hematopoietic stem cells (HSCs), and mesenchymal stromal/stem cells (MSCs) are all components of this microenvironment. CSCs are the HM initiators and are associated with neoplastic growth and drug resistance, while HSCs are able to reconstitute the entire hematopoietic system; finally, MSCs actively support hematopoiesis. In some HMs, CSCs and neoplastic cells compromise the normal development of HSCs and perturb BM-MSCs. In response, "reprogrammed" MSCs generate a favorable environment to support neoplastic cells. Extracellular vesicles (EVs) are an important cell-to-cell communication type in physiological and pathological conditions. In particular, in HMs, EV secretion participates to unidirectional and bidirectional interactions between neoplastic cells and BM cells. The transfer of EV molecular cargo triggers different responses in target cells; in particular, malignant EVs modify the BM environment in favor of neoplastic cells at the expense of normal HSCs, by interfering with antineoplastic immunity and participating in resistance to treatment. Here, we review the role of EVs in BM cell communication in physiological conditions and in HMs, focusing on the effects of BM niche EVs on HSCs and MSCs.

Extracellular vesicles in mesenchymal stromal cells: A novel therapeutic strategy for stroke

A stroke is a focal cerebral insult that frequently causes severe neurological deficit and mortality. Recent studies have demonstrated that multipotent mesenchymal stromal cells (MSCs) hold great promise for neurovascular remodeling and neurological function recovery following a stroke. Rather than a direct replacement of parenchymal brain cells, the therapeutic mechanism of MSCs is suggested to be the secretion of soluble factors. Specifically, emerging data described MSCs as being able to release extracellular vesicles (EVs), which contain a variety of cargo including proteins, lipids, DNA and various RNA species. The released EVs can target neurocytes and vascular cells and modify the cell's functions by delivering the cargo, which are considered to mediate the neural restoration effects of MSCs. Therefore, EVs may be developed as a novel cell-free therapy for neurological disorders. In the present review, the current advances regarding the components, functions and therapeutic potential of EVs are summarized and the use of MSC-derived EVs as a promising approach in the treatment of stroke are highlighted.

Circulating small-sized endothelial microparticles as predictors of clinical outcome after chemotherapy for breast cancer: an exploratory analysis

PURPOSE

Therapeutic exploitation of angiogenesis in breast cancer has been limited by the lack of reliable biomarkers. Circulating small-sized endothelial microparticles (sEMP) are likely to play a significant role as messengers of angiogenesis. Higher levels of EMP have been observed in cancer patients, but their prognostic value in breast cancer is unknown. Our aim was to determine the value of circulating sEMP as a marker of response to chemotherapy in breast cancer.

METHODS

We included patients with breast cancer treated with neoadjuvant or first-line chemotherapy. Baseline and post-treatment circulating sEMP (CD144+) were quantified using a flow cytometer approach specifically designed for analysis of small-sized particles (0.1-0.5 μm). Small-sized EMP response was defined as a post-treatment decrease of sEMP larger than the median decrease of sEMP after chemotherapy. Baseline and post-chemotherapy VEGFA levels were determined with ELISA.

RESULTS

Forty-four breast cancer patients were included (19 with metastatic and 25 with locally advanced disease). Median levels of sEMP decreased after chemotherapy (P = 0.005). Response to chemotherapy showed a non-significant trend to associate with sEMP response (P = 0.056). A sEMP response was observed in 51% of patients and was associated with better overall survival (HR 0.18; 95% CI 0.04-0.87; P = 0.02) and progression free survival (HR 0.30; 95% CI 0.09-0.99; P = 0.04) in the group of women with metastatic disease. Post-chemotherapy decrease of VEGFA levels was not associated with breast cancer prognosis.

CONCLUSIONS

Our results did not support sEMP as a marker of response to chemotherapy. However, our exploratory analysis suggests that in patients with metastatic breast cancer, the decrease of sEMP levels after chemotherapy is associated with better overall and disease free survival and might be superior to VEGFA levels as an angiogenesis-related prognostic marker.

Pathogenic roles of microvesicles in diabetic retinopathy

Diabetic retinopathy (DR) is a common complication of diabetes and has been recognized as the leading cause of blindness in adults. Several interrelated molecular pathways are involved in the development of DR. Microvesicles (MVs) are cell membrane vesicles, which carry many biologic molecules, such as mRNAs, microRNAs, transcription factors, membrane lipids, membrane receptors, and other proteins. They may be involved in intercellular communication that can promote inflammation, angiogenesis, and coagulation. Recent studies have indicated that changes in the number and composition of MVs may reflect the pathologic conditions of DR. At present, MVs are well recognized as being involved in the pathophysiological conditions of tumors and cardio-metabolic diseases. However, the roles of MVs in DR have yet to be investigated. In this review, we provide an overview of DR-induced microvascular injury that is caused by MVs derived from endothelial and circulating cells, and discuss the possible mechanisms by which MVs can lead to endothelial dysfunction, coagulation and inflammation. In addition, the protective effects of preconditioned MVs and stem cell-derived MVs are also described . Understanding the involvement of MVs in the pathophysiological conditions of DR may provide insight into the disease mechanisms and may suggest novel therapeutic strategies for DR in the future.

Endothelial cell-derived exosomes protect SH-SY5Y nerve cells against ischemia/reperfusion injury

Cerebral ischemia is a leading cause of death and disability. A previous study indicated that remote ischemic postconditioning (RIP) in the treatment of cerebral ischemia reduces ischemia/reperfusion (I/R) injury. However, the underlying mechanism is not well understood. In the present study, the authors hypothesized that the protective effect of RIP on neurological damage is mediated by exosomes that are released by endothelial cells in femoral arteries. To test this, right middle cerebral artery occlusion/reperfusion with RIP was performed in rats. In addition, an I/R injury cell model was tested that included human umbilical vein endothelial cells (HUVECs) and SH-SY5Y cells. Both the in vivo and in vitro models were examined for injury. Markers of exosomes (CD63, HSP70 and TSG101) were assessed by immunohistochemistry, western blot analysis and flow cytometry. Exosomes were extracted from both animal serum and HUVEC culture medium and identified by electron microscopy. They investigated the role of endothelial cell-derived exosomes in the proliferation, apoptosis, cell cycle, migration and invasion of I/R-injured SH-SY5Y cells. In addition, apoptosis-related molecules caspase-3, Bax and Bcl-2 were detected. RIP was determined to increase the number of exosomes and the expression levels of CD63, HSP70 and TSG101 in plasma, but not in brain hippocampal tissue. The size of exosomes released after I/R in HUVECs was similar to the size of exosomes released in rats subjected to RIP. Endothelial cell-derived exosomes partly suppressed the I/R-induced cell cycle arrest and apoptosis, and inhibited cell proliferation, migration and invasion in SH-SY5Y nerve cells. Endothelial cell-derived exosomes directly protect nerve cells against I/R injury, and are responsible for the protective role of RIP in I/R.

Exosomes as potential alternatives to stem cell therapy for intervertebral disc degeneration: in-vitro study on exosomes in interaction of nucleus pulposus cells and bone marrow mesenchymal stem cells

Background

The stem cell-based therapies for intervertebral disc degeneration have been widely studied. However, the mechanisms of mesenchymal stem cells interacting with intervertebral disc cells, such as nucleus pulposus cells (NPCs), remain unknown. Exosomes as a vital paracrine mechanism in cell–cell communication have been highly focused on. The purpose of this study was to detect the role of exosomes derived from bone marrow mesenchymal stem cells (BM-MSCs) and NPCs in their interaction with corresponding cells.

Methods

The exosomes secreted by BM-MSCs and NPCs were purified by differential centrifugation and identified by transmission electron microscope and immunoblot analysis of exosomal marker proteins. Fluorescence confocal microscopy was used to examine the uptake of exosomes by recipient cells. The effects of NPC exosomes on the migration and differentiation of BM-MSCs were determined by transwell migration assays and quantitative RT-PCR analysis of NPC phenotypic genes. Western blot analysis was performed to examine proteins such as aggrecan, sox-9, collagen II and hif-1α in the induced BM-MSCs. Proliferation and the gene expression profile of NPCs induced by BM-MSC exosomes were measured by Cell Counting Kit-8 and qRT-PCR analysis, respectively.

Results

Both the NPCs and BM-MSCs secreted exosomes, and these exosomes underwent uptake by the corresponding cells. NPC-derived exosomes promoted BM-MSC migration and induced BM-MSC differentiation to a nucleus pulposus-like phenotype. BM-MSC-derived exosomes promoted NPC proliferation and healthier extracellular matrix production in the degenerate NPCs.

Conclusion

Our study indicates that the exosomes act as an important vehicle in information exchange between BM-MSCs and NPCs. Given a variety of functions and multiple advantages, exosomes alone or loaded with specific genes and drugs would be an appropriate option in a cell-free therapy strategy for intervertebral disc degeneration.

How Do Mesenchymal Stem Cells Influence or Are Influenced by Microenvironment through Extracellular Vesicles Communication?

Mesenchymal stem cells (MSCs) are widely used in cell therapy and tissue engineering thanks to their self-renewal, their multipotency, and their immunomodulatory properties that make them an attractive tool for regenerative medicine. A large part of MSCs positive effects is due to their secretion products which participate in creating a favorable microenvironment and closely relate these cells to other cell types. Extracellular vesicles (EVs) belong to cellular secretions. They are produced by cells continuously or after stimulation (e.g., calcium flux, cellular stress) and act in tissue homeostasis and intercellular communication. The understanding of the role of EVs is growing, more particularly their impact on cell migration, differentiation, or immunomodulation. EVs derived from MSCs show these interesting properties that may be considered in therapeutics, although they can have adverse effects by facilitating cancer propagation. Moreover, MSC behavior may also be influenced (proliferation, differentiation) by EVs derived from other donor cells. The aim of this mini review is to summarize the two-way communication between MSCs and other cell types, and how they can affect each other with their microenvironment through EVs. On the one hand, the manuscript presents the influence of MSC-derived EVs on diverse recipient cells and on the other hand, the effects of EVs derived from various donor cells on MSCs. The discrepancies between cancer cells and MSCs communication according to the sources of MSCs but also the tumor origins are also mentioned.

Mesenchymal Stem Cell Treatment of Inflammation-Induced Cancer

Cancer development is often associated with chronic inflammation. To date, research into inflammation-induced cancer has largely focused on chemokines, cytokines, and their downstream targets. These inflammatory mediators may promote tumor growth, invasion, metastasis, and facilitate angiogenesis. However, the exact mechanisms by which inflammation promotes neoplasia remain unclear. Inflammatory bowel disease (IBD) is characterized by recurrent, idiopathic intestinal inflammation, the complications of which are potentially fatal. IBD incidence in Australia is 24.2 per 100,000 and its peak onset is in people aged 15 to 24 years. Symptoms include abdominal pain, cramps, bloody stool, and persistent diarrhoea or constipation and so seriously compromise quality of life. However, due to its unknown etiology, current treatment strategies combat the symptoms rather than the disease and are limited by inefficacy, toxicity, and adverse side-effects. IBD is also associated with an increased risk of colorectal cancer, for which treatment options are similarly limited. In recent years, there has been much interest in the therapeutic potential of mesenchymal stem cells (MSCs). However, whether MSCs suppress or promote tumor development is still contentious within the literature. Many studies indicate that MSCs exert anti-tumor effects and suppress tumor growth, whereas other studies report pro-tumor effects. Studies using MSCs as treatment for IBD have shown promising results in both animal models and human trials. However, as MSC treatment is still novel, the long-term risks remain unknown. This review aims to summarize the current literature on MSC treatment of inflammation-induced cancer, with a focus on colorectal cancer resulting from IBD.

Secreted trophic factors of mesenchymal stem cells support neurovascular and musculoskeletal therapies

Adult mesenchymal stem cells (MSCs) represent a subject of intense experimental and biomedical interest. Recently, trophic activities of MSCs have become the topic of a number of revealing studies that span both basic and clinical fields. In this review, we focus on recent investigations that have elucidated trophic mechanisms and shed light on MSC clinical efficacy relevant to musculoskeletal applications. Innate differences due to MSC sourcing may play a role in the clinical utility of isolated MSCs. Pain management, osteochondral, nerve, or blood vessel support by MSCs derived from both autologous and allogeneic sources have been examined. Recent mechanistic insights into the trophic activities of these cells point to ultimate regulation by nitric oxide, nuclear factor-kB, and indoleamine, among other signaling pathways. Classic growth factors and cytokines-such as VEGF, CNTF, GDNF, TGF-β, interleukins (IL-1β, IL-6, and IL-8), and C-C ligands (CCL-2, CCL-5, and CCL-23)-serve as paracrine control molecules secreted or packaged into extracellular vesicles, or exosomes, by MSCs. Recent studies have also implicated signaling by microRNAs contained in MSC-derived exosomes. The response of target cells is further regulated by their microenvironment, involving the extracellular matrix, which may be modified by MSC-produced matrix metalloproteinases (MMPs) and tissue inhibitor of MMPs. Trophic activities of MSCs, either resident or introduced exogenously, are thus intricately controlled, and may be further fine-tuned via implant material modifications. MSCs are actively being investigated for the repair and regeneration of both osteochondral and other musculoskeletal tissues, such as tendon/ligament and meniscus. Future rational and effective MSC-based musculoskeletal therapies will benefit from better mechanistic understanding of MSC trophic activities, for example using analytical "-omics" profiling approaches.

Effects of matrix metalloproteinases on the fate of mesenchymal stem cells

Mesenchymal stem cells (MSCs) have great potential as a source of cells for cell-based therapy because of their ability for self-renewal and differentiation into functional cells. Moreover, matrix metalloproteinases (MMPs) have a critical role in the differentiation of MSCs into different lineages. MSCs also interact with exogenous MMPs at their surface, and regulate the pericellular localization of MMP activities. The fate of MSCs is regulated by specific MMPs associated with a key cell lineage. Recent reports suggest the integration of MMPs in the differentiation, angiogenesis, proliferation, and migration of MSCs. These interactions are not fully understood and warrant further investigation, especially for their application as therapeutic tools to treat different diseases. Therefore, overexpression of a single MMP or tissue-specific inhibitor of metalloproteinase in MSCs may promote transdifferentiation into a specific cell lineage, which can be used for the treatment of some diseases. In this review, we critically discuss the identification of various MMPs and the signaling pathways that affect the differentiation, migration, angiogenesis, and proliferation of MSCs.

Biology and biogenesis of shed microvesicles

The ability of cells to transmit bioactive molecules to recipient cells and the extracellular environment is a fundamental requirement for both normal physiology and disease pathogenesis. It has traditionally been thought that soluble factors released from cells were responsible for this cellular signaling but recent research has revealed a fundamental role for microvesicles in this process. Microvesicles are heterogeneous membrane-bound sacs that are shed from the surface of cells into the extracellular environment in a highly regulated process. They are shed following the selective incorporation of a host of molecular cargo including multiple types of proteins and nucleic acids. In addition to providing new insight into the etiology of complex human diseases, microvesicles also show great promise as a tool for advanced diagnosis and therapy as we move forward into a new age of personalized medicine. Here we review current status of the rapidly evolving field of microvesicle biology, highlighting critical regulatory roles for several small GTPases in the biology and biogenesis of shed microvesicles.

Recapitulating epithelial tumor microenvironment in vitro using three dimensional tri-culture of human epithelial, endothelial, and mesenchymal cells

Background

Three-dimensional (3-D) cultures of cancer cells can potentially bridge the gap between 2-D drug screening and in vivo xenografts. The objective of this study was to characterize the cellular and extracellular matrix characteristics of spheroids composed of human lung epithelial cells (epi), pulmonary vascular endothelial (endo) cells, and human marrow-derived mesenchymal stems cells (MSCs).

Methods

Spheroids composed of epi/endo/MSCs, termed herein as synthetic tumor microenvironment mimics (STEMs), were prepared by the hanging drop method. Cellular composition and distribution in the STEMs was characterized using fluorescence microscopy. Induction of reactive oxygen species and upregulation of efflux transporters was quantified using fluorometry and PCR, respectively, and phenotypic markers were qualitatively assessed using immunohistochemistry.

Results

STEMs exhibited three unique characteristics not captured in other spheroid cultures namely, the presence of a spheroid core devoid of epithelial cells and primarily composed of MSCs, a small viable population of endothelial cells hypothesized to be closely associated with MSCs within the hypoxic core, and discrete regions with high expression for vimentin and cytokeratin-18, whose co-expression is co-related with enhanced metastasis. Although cells within STEMs show elevated levels of reactive oxygen species and mRNA for ABC-B1, an efflux transporter associated with drug resistance, they exhibited only modest resistance to paclitaxel and gemcitabine in comparison to 2-D tri-cultures.

Conclusions

The epi/endo/MSC spheroid model described herein offers a promising platform for understanding tumor biology and drug testing in vitro.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2634-1) contains supplementary material, which is available to authorized users.

Mesenchymal stem cells promote colorectal cancer progression through AMPK/mTOR-mediated NF-κB activation

Mesenchymal stem cells (MSCs) exert a tumor-promoting effect in a variety of human cancers. This study was designed to identify the molecular mechanisms related to the tumor-promoting effect of MSCs in colorectal cancer. In vitro analysis of colorectal cancer cell lines cultured in MSC conditioned media (MSC-CM) showed that MSC-CM significantly promoted the progression of the cancer cells by enhancing cell proliferation, migration and colony formation. The tumorigenic effect of MSC-CM was attributed to altered expression of cell cycle regulatory proteins and inhibition of apoptosis. Furthermore, MSC-CM induced high level expression of a number of pluripotency factors in the cancer cells. ELISAs revealed MSC-CM contained higher levels of IL-6 and IL-8, which are associated with the progression of cancer. Moreover, MSC-CM downregulated AMPK mRNA and protein phosphorylation, but upregulated mTOR mRNA and protein phosphorylation. The NF-κB pathway was activated after addition of MSC-CM. An in vivo model in Balb/C mice confirmed the ability of MSC-CM to promote the invasion and proliferation of colorectal cancer cells. This study indicates that MSCs promote the progression of colorectal cancer via AMPK/mTOR-mediated NF-κB activation.

Adipose-derived stem cells increase angiogenesis through matrix metalloproteinase-dependent collagen remodeling

Adipose-derived stem cells (ASCs) are key regulators of new blood vessel formation and widely investigated for their role in tissue regeneration and tumorigenesis. However, the cellular and molecular mechanisms through which ASCs regulate angiogenesis are not well understood. Here, it was our goal to test the functional contribution of ASC-mediated extracellular matrix (ECM) remodeling on endothelial cell invasion. To isolate the effect of ECM-remodeling, ASCs were embedded within 3-D collagen type I hydrogels and pre-cultured for 7 days; controls were not pre-cultured. A confluent monolayer of human umbilical vein endothelial cells (HUVECs) was seeded on top and its invasion into the underlying hydrogel was analyzed. Without pre-culture, ASCs inhibited vascular sprouting by stabilizing the endothelium. In contrast, 7 day pre-culture of ASCs drastically increased invasion by HUVECs. This effect was largely mediated by proteolytic ECM degradation by ASC-derived matrix metalloproteinases (MMPs) rather than vascular endothelial growth factor (VEGF), as our results indicated that blockade of MMPs, but not VEGF, inhibited endothelial sprouting. Collectively, these data suggest that the angiogenic capability of ASCs is modulated by their proteolytic remodeling of the ECM, opening new avenues for pro- and anti-angiogenic therapies.

In vitro expression of cytokeratin 18, 19 and tube formation of adipose-derived stem cells induced by the breast epithelial cell line HBL-100

Fat transplantation is increasingly used in breast augmentation; and recently, the issue of safety concerns from a cellular and molecular point of view has been raised. In this study, attentions were paid to the interaction between adipose-derived stem cells (ADSC) and mammary epithelial cells: human breast cancer cell line - 100 (HBL - 100) cells were used to simulate the normal microenvironment in breast tissue, ADSCs were harvest from human and co-cultured with HBL-100 cells. It was found that ADSCs formed tube-like structures in the co-culture with HBL-100 cells in contrast to the normal morphology of ADSCs in the control group. In addition, the immunofluorescence imaging showed that cytokeratin 18 and 19 (CK18 and 19) were significantly expressed in ADSCs after the co-culture with HBL-100 cells. The ultrastructure of those ADSCs also showed epithelial changes. In conclusion, ADSCs are not biological stable when co-cultured with HBL-100 cells. They differentiate into epithelial-like cells with the expression of epithelial surface marks (CK 18, 19) and form tube-like structures. This may offer an important evidence for the further study of clinical application of transplanting ADSCs rich adipose tissue into the breast in the future.

Membrane microparticles: shedding new light into cancer cell communication

BACKGROUND

Microparticles (MPs) or ectosomes are small enclosed fragments (from 0.2 to 2 μm in diameter) released from the cellular plasma membrane. Several oncogenic molecules have been identified inside MPs, including soluble proteins XIAP, survivin, metalloproteinases, CX3CL1, PYK2 and other microRNA-related proteins; membrane proteins EGFR, HER-2, integrins and efflux pumps; and messenger RNAs and microRNAs miR-21, miR-27a, let-7, miR-451, among others. Studies have shown that MPs transfer their cargo to neoplastic or non-malignant cells and thus contribute to activation of oncogenic pathways, resulting in cell survival, drug resistance and cancer dissemination.

DISCUSSION AND CONCLUSION

This review summarizes recent findings on MP biogenesis and the role of the MPs cargo in cancer and discusses some of the RNAs and proteins involved. In addition, the discussion covers evidence of (1) how and which signaling pathways can be activated by MPs in recipient cells; (2) recipient cell-type selectivity in incorporation of proteins and RNAs transported by MPs; and (3) how upon stimulation, stromal cells release MPs, promoting resistance to chemotherapeutics and invasiveness in cancer cells.