Interferon-β gene-modified human bone marrow mesenchymal stem cells attenuate hepatocellular carcinoma through inhibiting AKT/FOXO3a pathway

An Immunohistochemical Study of MAGE Proteins in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one the most common primary malignancies with high mortality and morbidity. The melanoma-associated antigen (MAGE) gene family includes several genes that are highly expressed in numerous human cancers, making many of them part of the cancer-testis antigen (CTA) family. MAGE-C1 is expressed in various malignancies but is absent in normal cells, except for the male germ line. Its presence is associated with a worse prognosis, increased tumor aggressiveness, and lymph node invasion. Similarly, MAGE-C2 is linked to the development of various malignant tumors. Despite these associations, the roles and mechanisms of MAGE-C1/MAGE-C2 in HCC remain unclear. This study aimed to evaluate the expression of MAGE-C1 and MAGE-C2 in HCC and correlate it with clinicohistological characteristics. Our findings indicated that MAGE-C1 expression is associated with a higher number of nodules, elevated AFP levels, HBV or HCV positivity, older age, male sex, and lymph node invasion. MAGE-C2 expression was correlated with these characteristics and the presence of cirrhosis. These results align with the limited literature, which suggests a correlation between MAGE expression and older age and HBV infection. Consequently, our study suggests that MAGE-C1 and MAGE-C2 are promising novel biomarkers for prognosis and potential therapeutic targets in HCC.

Interferon-β Overexpression in Adipose Tissue-Derived Stem Cells Induces HepG2 and Macrophage Cell Death in Liver Tumor Organoids via Induction of TNF-Related Apoptosis-Inducing Ligand Expression

Liver tumor organoids derived from liver tumor tissues and pluripotent stem cells are used for liver tumor research but have several challenges in primary cell isolation and stem cell differentiation. Here, we investigated the potential of HepG2-based liver tumor organoids for screening anticancer drugs by evaluating their responsiveness to IFN-β produced by mesenchymal stem cells (MSCs). Liver tumor organoids were prepared in three days on Matrigel using HepG2, primary liver sinusoidal epithelial cells (LSECs), LX-2 human hepatic stellate cells, and THP-1-derived macrophages at a ratio of 4:4:1:1, with 105 total cells. Hepatocyte-related and M2 macrophage-associated genes increased in liver tumor organoids. IFN-β treatment decreased the viability of liver tumor organoids and increased M1 macrophage marker expression (i.e., TNF-α and iNOS) and TRAIL. TRAIL expression was increased in all four cell types exposed to IFN-β, but cell death was only observed in HepG2 cells and macrophages. Further, MSCs overexpressing IFN-β (ASC-IFN-β) also expressed TRAIL, contributing to the reduced viability of liver tumor organoids. In summary, IFN-β or ASC-IFN-β can induce TRAIL-dependent HepG2 and macrophage cell death in HepG2-based liver tumor organoids, highlighting these liver tumor organoids as suitable for anticancer drug screening and mechanistic studies.

New insights in application of mesenchymal stem cells therapy in tumor microenvironment: pros and cons

Multipotent mesenchymal stem cells (MSCs) are widely accepted as a useful tool for cell-based therapy of various diseases including malignancies. The therapeutic effects of MSCs are mainly attributed to their immunomodulatory and immunosuppressive properties. Despite the promising outcomes of MSCs in cancer therapy, a growing body of evidence implies that MSCs also show tumorigenic properties in the tumor microenvironment (TME), which might lead to tumor induction and progression. Owing to the broad-spectrum applications of MSCs, this challenge needs to be tackled so that they can be safely utilized in clinical practice. Herein, we review the diverse activities of MSCs in TME and highlight the potential methods to convert their protumorigenic characteristics into onco-suppressive effects.

Cytokine sustained delivery for cancer therapy; special focus on stem cell- and biomaterial- based delivery methods

As immune regulators, cytokines serve critical role as signaling molecules in response to danger, tissue damage, or injury. Importantly, due to their vital role in immunological surveillance, cytokine therapy has become a promising therapeutics for cancer therapy. Cytokines have, however, been used only in certain clinical settings. Two key characteristics of cytokines contribute to this clinical translational challenge: first, they are highly pleiotropic, and second, in healthy physiology, they are typically secreted and act very locally in tissues. Systemic administration of the cytokines can consequently result in serious side effects. Thus, scientists have sought various strategies to circumvent theses hurdles. Recent in vivo reports signify that cytokine delivery platforms can increase their safety and therapeutic efficacy in tumor xenografts. Meanwhile, cytokine delivery using multipotent stem cells, in particular mesenchymal stem/stromal cells (MSCs), and also a diversity of particles and biomaterials has demonstrated greater capability in this regards. Herein, we take a glimpse into the recent advances in cytokine sustained delivery using stem cells and also biomaterials to ease safe and effective treatments of a myriad of human tumors.

Mesenchymal stem cells-based therapy in liver diseases

Multiple immune cells and their products in the liver together form a complex and unique immune microenvironment, and preclinical models have demonstrated the importance of imbalances in the hepatic immune microenvironment in liver inflammatory diseases and immunocompromised liver diseases. Various immunotherapies have been attempted to modulate the hepatic immune microenvironment for the purpose of treating liver diseases. Mesenchymal stem cells (MSCs) have a comprehensive and plastic immunomodulatory capacity. On the one hand, they have been tried for the treatment of inflammatory liver diseases because of their excellent immunosuppressive capacity; On the other hand, MSCs have immune-enhancing properties in immunocompromised settings and can be modified into cellular carriers for targeted transport of immune enhancers by genetic modification, physical and chemical loading, and thus they are also used in the treatment of immunocompromised liver diseases such as chronic viral infections and hepatocellular carcinoma. In this review, we discuss the immunological basis and recent strategies of MSCs for the treatment of the aforementioned liver diseases. Specifically, we update the immune microenvironment of the liver and summarize the distinct mechanisms of immune microenvironment imbalance in inflammatory diseases and immunocompromised liver diseases, and how MSCs can fully exploit their immunotherapeutic role in liver diseases with both immune imbalance patterns.

Interferon Beta (IFN-β)-Modified Bone Marrow Mesenchymal Stem Cells (BMSC) Impede Metastatic Tropism of Prostate Cancer via Modulating Transforming Growth Factor-Beta/Smads (TGF-Beta/Smads) Pathway

The study of Bone marrow mesenchymal stem cells (BMSCs)-based treatment is still unmet needs topic in recent years, especially focusing on the therapeutic effects of genetically modified BMSCs. IFN-β acts as a critical mediator in the occurrence and progress of prostate cancer. Additionally, its related signal transduction pathways affect malignancies. This study aims to discussion the mechanism of IFN-β-modified BMSCs in impeding the metastatic tropism of prostate cancer. A total of 40 male mice (SPF) with a clean grade were randomized into 4 groups (10 mice per group) as follows: control group, BMSCs group, IFN-β modified BMSCs group and TGF-beta/Smads inhibitor group. The following indicators were investigated: the expression level of IFN-β in IFN-β-modified BMSCs, in vitro metastatic tropism of prostate cancer cells, quantification of TGF-beta and Smads protein, along with the targeting of IFN-β and TGF-beta/Smads. The expression of IFN-β level was significantly increased denoted in the modified BMSCs (1.82±0.42) in comparison with those unmodified BMSCs (P < 0.05). After 48- and 72-hour culture, the proportion of migrating cells in the IFN-β-modified BMSCs group was significantly decreased than those in other groups (P < 0.05). Meanwhile, cells in the TGF-beta/Smads inhibitor group exhibited a significantly weaker tendency to migrate in comparison with those in the control group and BMSCs group, but still showed more migrating cells compared to cells in the IFN-β-modified BMSCs group (P < 0.05). Moreover, a significant reduction of migrated cells was denoted in the BMSCs group after 48- and 72-hour culture in comparison with the control group (P < 0.05). The weakest expression of TGF-beta/Smads proteins was denoted in the IFN-β-modified BMSCs group, followed by the TGF-beta/Smads inhibitor group, BMSCs group and control group (P < 0.05). The TGF-beta/Smads inhibitor group exhibited significantly decreased levels of TGF-beta/Smads proteins in comparison with the control group and BMSCs group (P < 0.05). Moreover, a significant decline of TGF-beta/Smads proteins was denoted in the BMSCs group in comparison with the control group (P < 0.05). The IFN-β gene was incubated separately with wild-type and mutant plasmids in the dual-luciferase reporter gene assay. The results indicated that the expression of IFN-β was stronger in the mutant plasmids (P < 0.05) IFN-β-modified BMSCs can boost the entrance of IFN-β into prostate cancer cells, thereby enhancing their expression of IFN-β, which resulted in the expression impediment of TGF-beta/Smads signals, leading to an inhibited metastatic tropism of prostate cancer cells. Its mechanism was mainly related to the TGF-beta/Smads signal transduction pathway.

The Roles of Mesenchymal Stem Cells in Gastrointestinal Cancers

Mesenchymal stem cells (MSCs) were reported to have strong immunomodulatory ability, and inhibit the proliferation of T cells and their immune response through cell-to-cell interactions and the generation of cytokines. With high differentiation potential and self-renewal ability, MSCs are considered to function in alleviating inflammatory responses, promoting tissue regeneration and inhibiting tissue fibrosis formation. As the most common malignancies, gastrointestinal (GI) cancers have high incidence and mortality. The accurate diagnosis, exact prognosis and treatment of GI cancers have always been a hot topic. Therefore, the potential applications of MSCs in terms of GI cancers are receiving more and more attention. Recently, there is increasing evidence that MSCs may serve as a key point in the growth, metastasis, inhibition, treatment and prognosis of GI cancers. In this review, we summarized the roles of MSCs in GI cancers, mainly focusing on esophageal cancer (EC), gastric cancer (GC), liver cancer (LC), colorectal cancer (CRC) and pancreatic cancer. Besides, we proposed MSCs as potential targets and treatment strategies for the effective treatment of GI cancers, which may provide better guidance for the clinical treatment of GI cancers.

Mesenchymal Stem Cell Exosomes and Cancer: Controversies and Prospects

Mesenchymal stem cells (MSCs) have displayed a novel therapeutic strategy for a wide range of diseases and conditions. Their secretome and exosome-based paracrine activity are considered as the main processes harboring their diverse therapeutic properties. Several investigations have examined the effects of MSC-derived exosomes on cancer growth, yet, controversial results have always emerged. Although MSC-derived exosomes are able to rigorously enforce the repression of cancer proliferation and progression, it is shown that MSCs exosomal activity displays numerous protumorigenic effects. This discrepancy over the dual effects of MSCs on cancer growth may be mediated by many factors including experimental design, stem cells origins, culture conditions, in addition to cancer-MSCs cross-talks. Despite the controversial effects of MSCs on carcinogenesis, scientists are able to overcome a number of obstacles by modifying MSCs to deliver antioncogenic miRNAs, anticancer drugs, and oncolytic viruses into tumor sites. This review discusses the controversial effects of MSC-derived exosomes on tumorigenesis, investigates the main causes that underlie this discrepancy, summarizes the pattern of engineered-MSCs, and finally highlights how future studies should advance the research in the field of MSCs-based cancer therapies in order to accelerate the transition from preclinical studies to clinical practice.

Mesenchymal Stem/Stromal Cells as a Vehicle for Cytokine Delivery: An Emerging Approach for Tumor Immunotherapy

Pro-inflammatory cytokines can effectively be used for tumor immunotherapy, affecting every step of the tumor immunity cycle. Thereby, they can restore antigen priming, improve the effector immune cell frequencies in the tumor microenvironment (TME), and eventually strengthen their cytolytic function. A renewed interest in the anticancer competencies of cytokines has resulted in a substantial promotion in the number of trials to address the safety and efficacy of cytokine-based therapeutic options. However, low response rate along with the high toxicity associated with high-dose cytokine for reaching desired therapeutic outcomes negatively affect their clinical utility. Recently, mesenchymal stem/stromal cells (MSCs) due to their pronounced tropism to tumors and also lower immunogenicity have become a promising vehicle for cytokine delivery for human malignancies. MSC-based delivery of the cytokine can lead to the more effective immune cell-induced antitumor response and provide sustained release of target cytokines, as widely evidenced in a myriad of xenograft models. In the current review, we offer a summary of the novel trends in cytokine immunotherapy using MSCs as a potent and encouraging carrier for antitumor cytokines, focusing on the last two decades' animal reports.

Importance of the origin of mesenchymal (stem) stromal cells in cancer biology: "alliance" or "war" in intercellular signals

Mesenchymal stem cells (MSCs) play a central role in the intercellular signaling within the tumor microenvironment (TME), exchanging signals with cancer cells and tumor stromal cells, such as cancer-associated fibroblasts and inflammatory mononuclear cells. Research attributes both pro-tumor and anti-tumor actions to MSCs; however, evidence indicates that MSCs specific effect on the tumor depends on the source of the MSCs and the type of tumor. There are consistent data proving that MSCs from reproductive tissues, such as the uterus, umbilical cord or placenta, have potent anti-tumor effects and tropism towards tumor tissues. More interestingly, products derived from MSCs, such as secretome or extracellular vesicles, seem to reproduce the effects of their parental cells, showing a potential advantage for clinical treatments by avoiding the drawbacks associated with cell therapy. Given these perspectives, it appears necessary new research to optimize the production, safety and antitumor potency of the products derived from the MSCs suitable for oncological therapies.

Mesenchymal stem/stromal cell-based therapy: mechanism, systemic safety and biodistribution for precision clinical applications

Mesenchymal stem/stromal cells (MSCs) are a promising resource for cell-based therapy because of their high immunomodulation ability, tropism towards inflamed and injured tissues, and their easy access and isolation. Currently, there are more than 1200 registered MSC clinical trials globally. However, a lack of standardized methods to characterize cell safety, efficacy, and biodistribution dramatically hinders the progress of MSC utility in clinical practice. In this review, we summarize the current state of MSC-based cell therapy, focusing on the systemic safety and biodistribution of MSCs. MSC-associated risks of tumor initiation and promotion and the underlying mechanisms of these risks are discussed. In addition, MSC biodistribution methodology and the pharmacokinetics and pharmacodynamics of cell therapies are addressed. Better understanding of the systemic safety and biodistribution of MSCs will facilitate future clinical applications of precision medicine using stem cells.

Therapeutic Effects of (5R)-5-Hydroxytriptolide on Fibroblast-Like Synoviocytes in Rheumatoid Arthritis via lncRNA WAKMAR2/miR-4478/E2F1/p53 Axis

Rheumatoid arthritis (RA) is an autoimmune disease. Fibroblast-like synoviocytes (FLS) serve a major role in synovial hyperplasia and inflammation in RA. (5R)-5-hydroxytriptolide (LLDT-8), a novel triptolide derivative, shows promising therapeutic effects for RA and is now in phase II clinical trials in China. However, the underlying mechanism of LLDT-8 is still not fully understood. Here, we found that LLDT-8 inhibited proliferation and invasion of RA FLS, as well as the production of cytokines. Microarray data demonstrated that LLDT-8 upregulated the expression of long non-coding RNA (lncRNA) WAKMAR2, which was negatively associated with proliferation and invasion of RA FLS, as well as the production of pro-inflammatory cytokines. Knockdown of WAKMAR2 abolished the inhibitory effects of LLDT-8 on RA FLS. Mechanistically, WAKMAR2 sponged miR-4478, which targeted E2F1 and downstreamed p53 signaling. Rescue experiments indicated that the inhibitory effects of LLDT-8 on RA FLS were dependent on WAKMAR2/miR-4478/E2F1/p53 axis.

Stem Cell Transplant for Advanced Stage Liver Disorders: Current Scenario and Future Prospects

BACKGROUND

Chronic Liver Disorders (CLD), caused by the lifestyle patterns like alcoholism or by non-alcoholic fatty liver disease or because of virus-mediated hepatitis, affect a large population fraction across the world. CLD progresses into end-stage diseases with a high mortality rate. Liver transplant is the only approved treatment available for such end-stage disease patients. However, the number of liver transplants is limited due to the limited availability of suitable donors and the extremely high cost of performing the procedure. Under such circumstances, Stem Cell (SC) mediated liver regeneration has emerged as a potential therapeutic alternative approach.

OBJECTIVE

This review aims to critically analyze the current status and future prospects of stem cellbased interventions for end-stage liver diseases. The clinical studies undertaken, the mechanism underlying therapeutic effects and future directions have been examined.

METHOD

The clinical trial databases were searched at https://clinicaltrials.gov.in and http://www.isrctn.com to identify randomized, non-randomized and controlled studies undertaken with keywords such as "liver disorder and Mesenchymal Stem Cells (MSCs)", "liver cirrhosis and MSCs" and "liver disorder and SCs". Furthermore, https://www.ncbi.nlm.nih.gov/pubmed/ database was also explored with similar keywords for finding the available reports and their critical analyses.

RESULTS

The search results yielded a significant number of studies that used bone marrow-derived stem cells, MSCs and hepatocytes. The studies clearly indicated that SCs play a key role in the hepatoprotection process by some mechanisms involving anti-inflammation, auto-immune-suppression, angiogenesis and anti-apoptosis. Further, studies indicated that SCs derived paracrine factors promote angiogenesis, reduce inflammation and inhibit hepatocyte apoptosis.

CONCLUSION

The SC-based interventions provide a significant improvement in patients with CLD; however, there is a need for randomized, controlled studies with the analysis of a long-term follow-up.

Mesenchymal stem cell therapy for liver disease: full of chances and challenges

Liver disease is a major health problem that endangers human health worldwide. Currently, whole organ allograft transplantation is the gold standard for the treatment of end-stage liver disease. A shortage of suitable organs, high costs and surgical complications limit the application of liver transplantation. Mesenchymal stem cell therapy has been considered as a promising alternative approach for end-stage liver disease. Some clinical trials have confirmed the effectiveness of MSC therapy for liver disease, but its application has not been promoted and approved. There are still many issues that should be solved prior to using MSC therapy in clinical applications. The types of liver disease that are most suitable for MSC application should be determined, and the preparation and engraftment of MSCs should be standardized. These may be bottlenecks that limit the use of MSCs. We investigated 22 completed and several ongoing clinical trials to discuss these questions from a clinical perspective. We also discussed the important mechanisms by which MSCs play a therapeutic role in liver disease. Finally, we also proposed novel prospective approaches that can improve the therapeutic effect of MSCs.

Stemness Potency of Human Gingival Cells-Application in Anticancer Therapies and Clinical Trials

Gingivae, as the part of periodontium, are involved in tooth support and possess the ability to heal rapidly, without scar formation. Recently, dental tissues have been identified as a potential source of mesenchymal stem cells (MSCs) and several populations of MSCs were isolated from the orofacial region, including gingival mesenchymal stem cells (GMSCs). GMSCs exhibit robust immunomodulatory and differentiation potential and are easily obtainable, which make them promising candidates for cellular therapies. Apart from being tested for application in immunologic- and inflammatory-related disorders and various tissue regeneration, GMSCs promise to be a valuable tool in cancer treatment, especially in tongue squamous cell carcinoma (TSCC) with the use of targeted therapy, since GMSCs are able to selectively migrate towards the cancerous cells both in vitro and in vivo. In addition to their ability to uptake and release anti-neoplastic drugs, GMSCs may be transduced with apoptosis-inducing factors and used for cancer growth inhibition. Moreover, GMSCs, as most mammalian cells, secrete exosomes, which are a subset of extracellular vesicles with a diameter of 40–160 nm, containing DNA, RNA, lipids, metabolites, and proteins. Such GMSCs-derived exosomes may be useful therapeutic tool in cell-free therapy, as well as their culture medium. GMSCs exhibit molecular and stem-cell properties that make them well suited in preclinical and clinical studies.

Genetically engineered mesenchymal stem cells: targeted delivery of immunomodulatory agents for tumor eradication

Cancer immunotherapy emerged as a novel therapeutic option that employs enhanced or amended native immune system to create a robust response against malignant cells. The systemic therapies with immune-stimulating cytokines have resulted in substantial dose-limiting toxicities. Targeted cytokine immunotherapy is being explored to overcome the heterogeneity of malignant cells and tumor cell defense with a remarkable reduction of systemic side effects. Cell-based strategies, such as dendritic cells (DCs), fibroblasts or mesenchymal stem cells (MSCs) seek to minimize the numerous toxic side effects of systemic administration of cytokines for extended periods of time. The usual toxicities comprised of a vascular leak, hypotension, and respiratory insufficiency. Natural and strong tropism of MSCs toward malignant cells made them an ideal systemic delivery vehicle to direct the proposed therapeutic genes to the vicinity of a tumor where their expression could evoke an immune reaction against the tumor. Compared with other methods, the delivery of cytokines via engineered MSCs is safer and renders a more practical, and promising strategy. Large numbers of genes code for cytokines have been utilized to reengineer MSCs as therapeutic cells. This review highlights the recent findings on the cytokine gene therapy for human malignancies by focusing on MSCs application in cancer immunotherapy.

Direct-acting antivirals and interferon-based therapy on hepatocellular carcinoma risk in chronic hepatitis-C patients

Aim: It was controversial whether direct-acting antiviral (DAA) is better than interferon-based therapy (IBT) in preventing HCV-related hepatocellular carcinoma (HCC). Therefore, we accomplished this large, stepwise meta-analysis. Materials & methods: The PubMed, Cochrane and ScienceDirect were searched for studies published during January 2009-March 2019. Antiviral type, number of chronic hepatitis C (CHC) patients, number of HCC cases from CHC patients, sustained virological response (SVR) status and important covariate data were extracted from each study. Results & conclusion: It is demonstrated that antiviral treatment reduces the occurrence of HCC in patients with CHC; achieving SVR to antiviral treatment reduces HCC; DAA treatment is not better than IBT in the prophylaxis of HCC; DAA treatment and cirrhosis are independently associated with a higher incidence of HCC than IBT in middle-aged CHC patients who achieve SVR.

p19Arf sensitizes B16 melanoma cells to interferon-β delivered via mesenchymal stem cells in vitro

The immune stimulatory and anti-neoplastic functions of type I interferon have long been applied for the treatment of melanoma. However, the systemic application of high levels of this recombinant protein is often met with toxicity. An approach that provides localized, yet transient, production of type I interferon may overcome this limitation. We propose that the use of mesenchymal stem cells (MSCs) as delivery vehicles for the production of interferon-β (IFNβ) may be beneficial when applied together with our cancer gene therapy approach. In our previous studies, we have shown that adenovirus-mediated gene therapy with IFNβ was especially effective in combination with p19Arf gene transfer, resulting in immunogenic cell death. Here we showed that MSCs derived from mouse adipose tissue were susceptible to transduction with adenovirus, expressed the transgene reliably, and yet were not especially sensitive to IFNβ production. MSCs used to produce IFNβ inhibited B16 mouse melanoma cells in a co-culture assay. Moreover, the presence of p19Arf in the B16 cells sensitizes them to the IFNβ produced by the MSCs. These data represent a critical demonstration of the use of MSCs as carriers of adenovirus encoding IFNβ and applied as an anti-cancer strategy in combination with p19Arf gene therapy.

Mesenchymal stem cells as carriers for systemic delivery of oncolytic viruses

Progress in genetic engineering led to the emergence of some viruses as potent anticancer therapeutics. These oncolytic viruses combine self-amplification with dual antitumor action: oncolytic (destruction of cancer cells) and immunostimulatory (eliciting acquired antitumor response against cancer epitopes). As any other viruses, they trigger antiviral response upon systemic administration. Mesenchymal stem cells are immature cells capable of self-renewing and differentiating into many cell types that belong to three germinal layers. Due to their inherent tumor tropism mesenchymal stem cells loaded with oncolytic virus can improve delivery of the therapeutic cargo to cancer sites. Shielding of oncolytic viral construct from antiviral host immune response makes these cells prospective delivery vehicles to even hard-to-reach metastatic neoplastic foci. Use of mesenchymal stem cells has been criticized by some investigators as limiting proliferative abilities of primary cells and increasing the risk of malignant transformation, as well as attenuating therapeutic responses. However, majority of preclinical studies indicate safety and efficacy of mesenchymal stem cells used as carriers of oncolytic viruses. In view of contradictory postulates, the debate continues. The review discusses mesenchymal stem cells as carriers for delivery of genetically engineered oncolytic constructs and focuses on systemic approach to oncoviral treatment of some deadly neoplasms.

Bidirectional and Opposite Effects of Naïve Mesenchymal Stem Cells on Tumor Growth and Progression

Cancer has long been considered as a heterogeneous population of uncontrolled proliferation of different transformed cell types. The recent findings concerning tumorigeneses have highlighted the fact that tumors can progress through tight relationships among tumor cells, cellular, and non-cellular components which are present within tumor tissues. In recent years, studies have shown that mesenchymal stem cells (MSCs) are essential components of non-tumor cells within the tumor tissues that can strongly affect tumor development. Several forms of MSCs have been identified within tumor stroma. Naïve (innate) mesenchymal stem cells (N-MSCs) derived from different sources are mostly recruited into the tumor stroma. N-MSCs exert dual and divergent effects on tumor growth through different conditions and factors such as toll-like receptor priming (TLR-priming), which is the primary underlying causes of opposite effects. Moreover, MSCs also have the contrary effects by various molecular mechanisms relying on direct cellto- cell connections and indirect communications through the autocrine, paracrine routes, and tumor microenvironment (TME).

Overall, cell-based therapies will hold great promise to provide novel anticancer treatments. However, the application of intact MSCs in cancer treatment can theoretically cause adverse clinical outcomes. It is essential that to extensively analysis the effective factors and conditions in which underlying mechanisms are adopted by MSCs when encounter with cancer.

The aim is to review the cellular and molecular mechanisms underlying the dual effects of MSCs followed by the importance of polarization of MSCs through priming of TLRs.

Activation of the Toll‑like receptor 2 signaling pathway inhibits the proliferation of HCC cells in vitro

Toll‑like receptor 2 (TLR2), is an important pattern recognition receptor which serves a role in chronic inflammation of the liver. However, the role of TLR2 in the progression of human hepatocellular carcinoma (HCC) remains unknown. The aim of the present study was to examine the effects of the activation of the TLR2 signaling pathway on biological functions, such as proliferation and apoptosis. TLR2 expression in HCC tissues was assayed by quantitative polymerase chain reaction, flow cytometry and western blotting. B76/Huh7 cells were transfected with overexpression plasmids, and cell proliferation was detected using a Cell Counting Kit‑8 assay and the secreted cytokines in the supernatant of transfected cells were measured by ELISA. The findings revealed that TLR2 expression was increased in the peritumoral groups compared with inner‑tumoral groups. Activation of the TLR2 signaling pathway through overexpression of pathway molecules inhibited the growth of B76/Huh7 cells and the secretion of interleukin‑6 and tumor necrosis factor‑α were reduced. Inhibition of the TLR2 signaling pathway resulted in a significant increase in the downstream signaling cascade, thus potentially increasing hepatocarcinogenesis and tumor progression. Activation of the TLR2 signaling pathway may be a potential target for therapeutic intervention in patients with HCC and downstream secreted cytokines are required for the functional biological effect. Therefore, modulation of the TLR2 signaling pathway may provide important insight into designing effective therapeutic regimens for treating patients with HCC.

The growth inhibitory effect of human gingiva-derived mesenchymal stromal cells expressing interferon-β on tongue squamous cell carcinoma cells and xenograft model

BACKGROUND

Interferon-β (IFN-β) is a cytokine with pleiotropic cellular functions, including antiviral, antiproliferative, and immunomodulatory activities. IFN-β inhibits multiple tumor cell growth in vitro. However, the contradiction between the therapeutic dose of IFN-β and its maximally tolerated dose is still inextricable in vivo. Human gingiva-derived mesenchymal stromal cells (GMSCs) represent promising vehicles for cancer gene therapy. This study evaluated the potential of GMSCs genetically engineered to produce IFN-β as a targeted gene delivery system to treat tongue squamous cell carcinoma (TSCC) in vitro and in vivo.

METHODS

A lentiviral vector encoding IFN-β was constructed and transfected into GMSCs to obtain IFN-β gene-modified GMSCs (GMSCs/IFN-β). Enzyme-linked immunosorbent assay (ELISA) was used to measure the IFN-β concentration in conditioned medium (CM) from GMSCs/IFN-β. The Cell Counting Kit-8 (CCK8), colony formation assay, and flow cytometry were used to detect the effects of GMSCs/IFN-β on TSCC cell line CAL27 cell growth and apoptosis in vitro. TSCC xenograft model was developed by subcutaneous injection of CAL27 cells into BALB/c nude mouse, and the role of intravenously injected GMSCs/IFN-β in engrafting in TSCC and controlling tumor progression was measured in vivo.

RESULTS

GMSCs/IFN-β expressed a high level of IFN-β. Both CCK8 and colony forming assay showed that GMSCs/IFN-β significantly inhibited the proliferation of CAL27 cells compared with the GMSCs, GMSCs/vector, or DMEM group. Flow cytometry analysis demonstrated that the CAL27 cell apoptosis rate was higher in the GMSCs/IFN-β group than in the other three groups. The in vivo experiment revealed that GMSCs/IFN-β engrafted selectively in TSCC xenograft and expressed a high level of IFN-β. There were smaller tumor volume and lower number of Ki67-positive cells in the GMSCs/IFN-β group than in the GMSCs, GMSCs/vector, or phosphate-buffered saline (PBS) group. Interestingly, GMSCs and GMSCs/vector also presented the potential of CAL27 cell growth inhibition in vitro and in vivo, although such an effect was weaker than GMSCs/IFN-β.

CONCLUSIONS

GMSCs/IFN-β inhibits the proliferation of TSCC cells in vitro and in vivo. These results provide evidence that delivery of IFN-β by GMSCs may be a promising approach to develop an effective treatment option for TSCC therapy.

Mesenchymal stromal cells for bone sarcoma treatment: Roadmap to clinical practice

Over the past few decades, there has been growing interest in understanding the molecular mechanisms of cancer pathogenesis and progression, as it is still associated with high morbidity and mortality. Current management of large bone sarcomas typically includes the complex therapeutic approach of limb salvage or sacrifice combined with pre- and postoperative multidrug chemotherapy and/or radiotherapy, and is still associated with high recurrence rates. The development of cellular strategies against specific characteristics of tumour cells appears to be promising, as they can target cancer cells selectively. Recently, Mesenchymal Stromal Cells (MSCs) have been the subject of significant research in orthopaedic clinical practice through their use in regenerative medicine. Further research has been directed at the use of MSCs for more personalized bone sarcoma treatments, taking advantage of their wide range of potential biological functions, which can be augmented by using tissue engineering approaches to promote healing of large defects. In this review, we explore the use of MSCs in bone sarcoma treatment, by analyzing MSCs and tumour cell interactions, transduction of MSCs to target sarcoma, and their clinical applications on humans concerning bone regeneration after bone sarcoma extraction.

Mesenchymal Stem Cells and Cancer: Clinical Challenges and Opportunities

Stem cell-based therapies exhibit profound therapeutic potential for treating various human diseases, including cancer. Among the cell types that can be used for this purpose, mesenchymal stem cells (MSCs) are considered as promising source of stem cells in personalized cell-based therapies. The inherent tumor-tropic property of MSCs can be used to target cancer cells. Although the impacts of MSCs on tumor progression remain elusive, they have been genetically modified or engineered as targeted anticancer agents which could inhibit tumor growth by blocking different processes of tumor. In addition, there are close interactions between MSCs and cancer stem cells (CSCs). MSCs can regulate the growth of CSCs through paracrine mechanisms. This review aims to focus on the current knowledge about MSCs-based tumor therapies, the opportunities and challenges, as well as the prospective of its further clinical implications.

Multipotent mesenchymal stromal cells play critical roles in hepatocellular carcinoma initiation, progression and therapy

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, with high morbidity, relapse and mortality rates. Multipotent mesenchymal stromal cells (MSCs) can be recruited to and become integral components of the HCC microenvironment and can influence tumor progression. This review discusses MSC migration to liver fibrosis and the HCC microenvironment, MSC involvement in HCC initiation and progression and the widespread application of MSCs in HCC-targeted therapy, thus clarifying the critical roles of MSCs in HCC.

Mesenchymal stem cells in preclinical cancer cytotherapy: a systematic review

Mesenchymal stem cells (MSC) comprise a heterogeneous population of rapidly proliferating cells that can be isolated from adult (e.g., bone marrow, adipose tissue) as well as fetal (e.g., umbilical cord) tissues (termed bone marrow (BM)-, adipose tissue (AT)-, and umbilical cord (UC)-MSC, respectively) and are capable of differentiation into a wide range of non-hematopoietic cell types. An additional, unique attribute of MSC is their ability to home to tumor sites and to interact with the local supportive microenvironment which rapidly conceptualized into MSC-based experimental cancer cytotherapy at the turn of the century. Towards this purpose, both naïve (unmodified) and genetically modified MSC (GM-MSC; used as delivery vehicles for the controlled expression and release of antitumorigenic molecules) have been employed using well-established in vitro and in vivo cancer models, albeit with variable success. The first approach is hampered by contradictory findings regarding the effects of naïve MSC of different origins on tumor growth and metastasis, largely attributed to inherent biological heterogeneity of MSC as well as experimental discrepancies. In the second case, although the anti-cancer effect of GM-MSC is markedly improved over that of naïve cells, it is yet apparent that some protocols are more efficient against some types of cancer than others. Regardless, in order to maximize therapeutic consistency and efficacy, a deeper understanding of the complex interaction between MSC and the tumor microenvironment is required, as well as examination of the role of key experimental parameters in shaping the final cytotherapy outcome. This systematic review represents, to the best of our knowledge, the first thorough evaluation of the impact of experimental anti-cancer therapies based on MSC of human origin (with special focus on human BM-/AT-/UC-MSC). Importantly, we dissect the commonalities and differences as well as address the shortcomings of work accumulated over the last two decades and discuss how this information can serve as a guide map for optimal experimental design implementation ultimately aiding the effective transition into clinical trials.

Promotion of Cell-Based Therapy: Special Focus on the Cooperation of Mesenchymal Stem Cell Therapy and Gene Therapy for Clinical Trial Studies

Regenerative medicine (RM) is a promising new field of medicine that has mobilized several new tools to repair or replace lost or damaged cells or tissues by stimulating natural regenerative mechanisms nearby cell and tissue-based therapy approaches. However, mesenchymal stem cell (MSC) based therapy has been shown to be safe and effective to a certain degree in multiple clinical trial studies (CTSs) of several diseases, in most MSC CTSs the efficacy of treatment has been reported low. Therefore, researchers have focused on efficacy enhancing of MSC to improve migratory and homing, survival, stemness, differentiation and other therapeutic applicable properties by using different approaches. Gene therapy is one of the experimental technique tools that uses genes to change cells for therapeutic and investigation purposes. In this study has been focused on genetically modified MSCs for use in RM with an emphasis on CTSs. We highlight the basic concept of genetic modifications and also discuss recent clinical studies aspects. Recently reviewed studies show that MSC therapy with assistant gene therapy can be used in cancer therapy, heart diseases, Fanconi anemia and several other diseases.

The future of mesenchymal stem cell-based therapeutic approaches for cancer - From cells to ghosts

Mesenchymal stem cells (MSCs) are multipotent stromal cells which can differentiate into a variety of cell types including osteoblasts, adipocytes and chondrocytes. They are normally resident in adipose tissue, bone marrow and the umbilical cord, but can also be found in other tissues and are known to be recruited to sites of wound healing as well as growing tumours. The therapeutic potential of MSCs has been explored in a number of phase I/II and III clinical trials, of which several were targeted against graft-versus-host disease and to support engraftment of haematopoietic stem cells (HSCs), but currently only very few in the oncology field. There are now three clinical trials either ongoing or recruiting patients that use MSCs to treat tumour disease. In these, MSCs target gastrointestinal, lung and ovarian cancer, respectively. The first study uses MSCs loaded with a HSV-TK expression construct under the control of the CCL5 promoter, and has recently reported successful completion of Phase I/II. While no adverse side effects were seen during this study, no outcomes with respect to therapeutic benefits have been published. The other clinical trials targeting lung and ovarian cancer will be using MSCs expressing cytokines as therapeutic payload. Despite these encouraging early steps towards their clinical use, many questions are still unanswered regarding the biology of MSCs in normal and pathophysiological settings. In this review, in addition to summarising the current state of MSC-based therapeutic approaches for cancer, we will describe the remaining questions, obstacles and risks, as well as novel developments such as MSC-derived nanoghosts.

Essential role of HCMV deubiquitinase in promoting oncogenesis by targeting anti-viral innate immune signaling pathways

Cancer is a multifactorial disease and virus-mediated carcinogenesis is one of the crucial factors, which is poorly understood. Human cytomegalovirus (HCMV) is a herpesvirus and its components have been evidenced to be associated with cancer of different tissue origin. However, its role in cancer remains unknown. Here, we identified a conserved herpesviral tegument protein known as pUL48 of HCMV, encoding deubiquitinase enzyme, as having a key role in carcinogenesis. We show using deubiquitinase sufficient- and deficient-HCMV that HCMV deubiquitinase is a key in inducing enhanced cellular metabolic activity through upregulation of several anti-apoptotic genes and downregulation of several pro-apoptotic genes expression. Furthermore, HCMV deubiquitinase acquires pro-tumor functions by inhibiting PRR-mediated type I interferon via deubiquitination of TRAF6, TRAF3, IRAK1, IRF7 and STING. Taken together, our results suggest that HCMV infection may promote oncogenesis by inhibiting innate immunity of the host.

Targeted antitumor therapy mediated by prodrug-activating mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) were introduced as tumor-targeted vehicles suitable for delivery of the gene-directed enzyme/prodrug therapy more than 10 years ago. Over these years key properties of tumor cells and MSCs, which are crucial for the treatment efficiency, were examined; and there are some critical issues to be considered for the maximum antitumor effect. Moreover, engineered MSCs expressing enzymes capable of activating non-toxic prodrugs achieved long-term curative effect even in metastatic and hard-to-treat tumor types in pre-clinical scenario(s). These gene-modified MSCs are termed prodrug-activating MSCs throughout the text and represent promising approach for further clinical application. This review summarizes major determinants to be considered for the application of the prodrug-activating MSCs in antitumor therapy in order to maximize therapeutic efficiency.

Tumor-educated mesenchymal stem cells promote pro-metastatic phenotype

Multipotent mesenchymal stem cells (MSCs) are recruited into tumor microenvironment in response to multiple signals produced by cancer cells. Molecules involved in their homing to tumors are the same inflammatory mediators produced by injured tissues: chemokines, cytokines and growth factors. When MSCs arrive into the tumor microenvironment these are “educated” to have pro-metastatic behaviour. Firstly, they promote cancer immunosuppression modulating both innate and adaptive immune systems. Moreover, tumor associated-MSCs trans-differentiating into cancer-associated fibroblasts can induce epithelial-mesenchymal-transition program in tumor cells. This process determinates a more aggressive phenotype of cancer cells by increasing their motility and invasiveness and favoring their dissemination to distant sites. In addition, MSCs are involved in the formation and modelling of pre-metastatic niches creating a supportive environment for colonization of circulating tumor cells.

The development of novel therapeutic approaches targeting the different functions of MSCs in promoting tumor progression as well as the mechanisms underlying their activities could enhance the efficacy of conventional and immune anti-cancer therapies.

Furthermore, many studies report the use of MSCs engineered to express different genes or as vehicle to specifically deliver novel drugs to tumors exploiting their strong tropism. Importantly, this approach can enhance local therapeutic efficacy and reduce the risk of systemic side effects.

Genetically modified mesenchymal stromal cells in cancer therapy

The cell therapy industry has grown rapidly over the past 3 decades, and multiple clinical trials have been performed to date covering a wide range of diseases. The most frequently used cell is mesenchymal stromal cells (MSCs), which have been used largely for their anti-inflammatory actions and in situations of tissue repair and although they have demonstrated a good safety profile, their therapeutic efficacy has been limited. In addition to these characteristics MSCs are being used for their homing and engraftment properties and have been genetically modified to enable targeted delivery of a variety of therapeutic agents in both malignant and nonmalignant conditions. This review discusses the science and technology behind genetically modified MSC therapy in malignant disease and how potential problems have been overcome to enable their use in two novel clinical trials in metastatic gastrointestinal and lung cancer.

Engineered Mesenchymal Stem Cells as an Anti-Cancer Trojan Horse

Cell-based gene therapy holds a great promise for the treatment of human malignancy. Among different cells, mesenchymal stem cells (MSCs) are emerging as valuable anti-cancer agents that have the potential to be used to treat a number of different cancer types. They have inherent migratory properties, which allow them to serve as vehicles for delivering effective therapy to isolated tumors and metastases. MSCs have been engineered to express anti-proliferative, pro-apoptotic, and anti-angiogenic agents that specifically target different cancers. Another field of interest is to modify MSCs with the cytokines that activate pro-tumorigenic immunity or to use them as carriers for the traditional chemical compounds that possess the properties of anti-cancer drugs. Although there is still controversy about the exact function of MSCs in the tumor settings, the encouraging results from the preclinical studies of MSC-based gene therapy for a large number of tumors support the initiation of clinical trials.

The Roles of Mesenchymal Stromal/Stem Cells in Tumor Microenvironment Associated with Inflammation

State of tumor microenvironment (TME) is closely linked to regulation of tumor growth and progression affecting the final outcome, refractoriness, and relapse of disease. Interactions of tumor, immune, and mesenchymal stromal/stem cells (MSCs) have been recognized as crucial for understanding tumorigenesis. Due to their outstanding features, stem cell-like properties, capacity to regulate immune response, and dynamic functional phenotype dependent on microenvironmental stimuli, MSCs have been perceived as important players in TME. Signals provided by tumor-associated chronic inflammation educate MSCs to alter their phenotype and immunomodulatory potential in favor of tumor-biased state of MSCs. Adjustment of phenotype to TME and acquisition of tumor-promoting ability by MSCs help tumor cells in maintenance of permissive TME and suppression of antitumor immune response. Potential utilization of MSCs in treatment of tumor is based on their inherent ability to home tumor tissue that makes them suitable delivery vehicles for immune-stimulating factors and vectors for targeted antitumor therapy. Here, we review data regarding intrusive effects of inflammatory TME on MSCs capacity to affect tumor development through modification of their phenotype and interactions with immune system.

Clinicopathological role of miR-30a-5p in hepatocellular carcinoma tissues and prediction of its function with bioinformatics analysis

BACKGROUND

It has been reported that deregulation or dysfunction of microRNAs (miRNAs) plays an essential part in the hepatocarcinogenesis. However, the contribution and mechanism of microRNA-30a-5p (miR-30a-5p) in hepatocellular carcinoma (HCC) remains largely unknown. Therefore, our aim was to investigate the clinicopathological role of miR-30a-5p in HCC tissues and explore its potential pathways in this study.

METHODS

The expression of miR-30a-5p was measured in 95 HCC and adjacent noncancer tissues by real-time reverse transcription quantitative polymerase chain reaction. The relationship between miR-30a-5p expression levels and clinicopathological parameters was also analyzed. Furthermore, the potential target genes of miR-30a-5p were collected via online prediction and literature searching. Gene ontology and pathway enrichment analyses were used to identify the possible function of miR-30a-5p in HCC.

RESULTS

Compared with adjacent noncancer tissues (2.23±0.77), expression level of miR-30a-5p was significantly lower in HCC tissues (1.26±0.66, P<0.001). MiR-30a-5p expression was evidently correlated with tumor nodes, metastasis, tumor-node-metastasis stage, portal vein tumor embolus, vascular invasion, and status of tumor capsule (all P<0.05). A total of 878 genes were finally used for the biological informatics analyses. These prospective target genes were highly enriched in various key pathways, for instance, Ubiquitin-mediated proteolysis, Axon guidance, Neurotrophin signaling pathway, Amyotrophic lateral sclerosis, and ErbB signaling pathway.

CONCLUSION

In conclusion, this study clarifies that the downregulation of miRNA-30a-5p might play a vital part in the incidence and progression of HCC via targeting various prospective genes and pathways. Future validation is required to further explore the prospective molecular mechanism of miR-30a-5p in HCC.

Opposite Effects of Coinjection and Distant Injection of Mesenchymal Stem Cells on Breast Tumor Cell Growth

: Mesenchymal stem cells (MSCs) usually promote tumor growth and metastasis. By using a breast tumor 4T1 cell-based animal model, this study determined that coinjection and distant injection of allogeneic bone marrow-derived MSCs with tumor cells could exert different effects on tumor growth. Whereas the coinjection of MSCs with 4T1 cells promoted tumor growth, surprisingly, the injection of MSCs at a site distant from the 4T1 cell inoculation site suppressed tumor growth. We further observed that, in the distant injection model, MSCs decreased the accumulation of myeloid-derived suppressor cells and regulatory T cells in tumor tissues by enhancing proinflammatory factors such as interferon-γ, tumor necrosis factor-α, Toll-like receptor (TLR)-3, and TLR-4, promoting host antitumor immunity and inhibiting tumor growth. Unlike previous reports, this is the first study reporting that MSCs may exert opposite roles on tumor growth in the same animal model by modulating the host immune system, which may shed light on the potential application of MSCs as vehicles for tumor therapy and other clinical applications.

SIGNIFICANCE

Mesenchymal stem cells (MSCs) have been widely investigated for their potential roles in tissue engineering, autoimmune diseases, and tumor therapeutics. This study explored the impact of coinjection and distant injection of allogeneic bone marrow-derived MSCs on mouse 4T1 breast cancer cells. The results showed that the coinjection of MSCs and 4T1 cells promoted tumor growth. MSCs might act as the tumor stromal precursors and cause immunosuppression to protect tumor cells from immunosurveillance, which subsequently facilitated tumor metastasis. Interestingly, the distant injection of MSCs and 4T1 cells suppressed tumor growth. Together, the results of this study revealed the dual functions of MSCs in immunoregulation.

Metformin induces apoptosis of human hepatocellular carcinoma HepG2 cells by activating an AMPK/p53/miR-23a/FOXA1 pathway

The antidiabetic drug metformin has been shown to possess antitumor functions in many types of cancers. Although studies have revealed its beneficial effects on the prognosis of hepatocellular carcinoma (HCC), the detailed molecular mechanism underlying this event remains largely unknown. In this work, we showed that miR-23a was significantly induced upon metformin treatment; inhibition of miR-23a abrogated the proapoptotic effect of metformin in HepG2 cells. We next established forkhead box protein A1 (FOXA1) as the functional target of miR-23a, and silencing FOXA1 mimicked the effect of metformin. Moreover, the phosphorylation of AMP-activated protein kinase (AMPK) and the expression of p53 were increased upon metformin treatment, and the inhibition of p53 abrogated the induction of miR-23a by metformin, suggesting that AMPK/p53 signaling axis is responsible for the induction of miR-23a by metformin. In summary, we unraveled a novel AMPK/p53/miR-23a/FOXA1 axis in the regulation of apoptosis in HCC, and the application of metformin could, therefore, be effective in the treatment of HCC.

Primary ovarian cancer cell inhibition by human Wharton's Jelly stem cells (hWJSCs): Mapping probable mechanisms and targets using systems oncology

Ovarian cancer is one of the most lethal gynaecological cancers. Its subtle onset and absence of symptoms in early stages are associated with poor prognosis and high mortality. Identification of early biomarkers would aid in ovarian cancer control. Mesenchmal stem cells (MSCs) and/or their secretory products are identified to have cancer inhibitory properties. Therefore, it is of interest to study the anticancer properties of human Wharton's jelly stem cells conditioned medium (hWJSCs-CM) on primary ovarian carcinoma cells in vitro. Primary cultures of epithelial ovarian carcinoma cells (EOCs) and hWJSCs were used in this study. EOCs were exposed to hWJSC-CM (100%) for 24h-72h and changes in mophology and cell proliferation were monitored. Treatment with hWJSC-CM showed altered morphological changes that resulted in death of EOCs. Colorimetric assay [MTT, (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide)] showed mean decreases in EOC proliferation by 16.21%, 23.89% and 40.08% at 24h, 48h and 72h respectively compared to control. Ingenuity Pathway Analysis (IPA, Igenuity Systems, USA) deduced important molecular pathways and signaling networks associated with cancer cell death and these correlated with significant expression of tumour suppresors and apoptotic genes in hWJSCs. Secretory products of hWJSC-CM induced cell death of EOCs via apoptosis. IPA identification of canonical genes/pathways involved in EOCs that overlap with hWJSCs tumour suppressors and apoptosis genes further support this hypotheis. Additional in vitro and in vivo studies are necessary to validate EOCs inhibition with hWJSC-extracts towards their mechanism of action.

Interferon-α2b gene-modified human bone marrow mesenchymal stem cells inhibit hepatocellular carcinoma by reducing the Notch1 levels

AIMS

Hepatocellular carcinoma (HCC) is the most common liver cancer worldwide. IFN-α has been used in clinics as a potential therapeutic strategy to treat HCC. In spite of the therapeutic effects, IFN-α caused many side effects due to its short half-life and high dose. Here, we aim to detect the anti-tumor effect of a novel gene delivery system - IFN-α2b gene-modified human bone marrow mesenchymal stem cells (BMSCs) in HCC.

MAIN METHODS

Two HCC cell lines, HepG2 and Huh7 were used in the current study. The secretion of IFN-α2b in the BMSC cultured conditioned media (CM) was measured by ELISA. The cell cycle was determined by flow cytometry. The Xenografted NOD/SCID mouse tumor model was generated by subcutaneous inoculation with HepG2 cells.

KEY FINDINGS

We found that the IFN-α2b-modified BMSC (BMSC/IFN-α2b) could express IFN-α2b stably. The CM from BMSC/IFN-α2b inhibited the proliferation of HCC cells with a much lower growth rate compared with BMSC/vector-CM or DMEM culture group. We further demonstrated that the population of G2/M phase was higher in BMSC/IFN-α2b-CM treated cells than the other two groups. In addition, BMSC/IFN-α2b could significantly inhibit tumor growth in NOD/SCID mice. Moreover, we found that BMSC/IFN-α2b-CM could significantly decrease the mRNA and protein levels of Notch signaling molecules of HCC in vitro and in vivo.

SIGNIFICANCE

Our data demonstrated that BMSC/IFN-α2b could significantly inhibit HCC cell growth through negatively regulating the Notch signaling, which suggested that IFN-α2b-modified BMSC may be used as an effective therapeutic strategy for hepatomas.

JAM-A promotes wound healing by enhancing both homing and secretory activities of mesenchymal stem cells

The homing ability and secretory function of mesenchymal stem cells (MSCs) are key factors that influence cell involvement in wound repair. These factors are controlled by multilayer regulatory circuitry, including adhesion molecules, core transcription factors (TFs) and certain other regulators. However, the role of adhesion molecules in this regulatory circuitry and their underlying mechanism remain undefined. In the present paper, we demonstrate that an adhesion molecule, junction adhesion molecule A (JAM-A), may function as a key promoter molecule to regulate skin wound healing by MSCs. In in vivo experiments, we show that JAM-A up-regulation promoted both MSC homing to full-thickness skin wounds and wound healing-related cytokine secretion by MSCs. In vitro experiments also showed that JAM-A promoted MSC proliferation and migration by activating T-cell lymphoma invasion and metastasis 1 (Tiam1). We suggest that JAM-A up-regulation can increase the proliferation, cytokine secretion and wound-homing ability of MSCs, thus accelerating the repair rate of full-thickness skin defects. These results may provide insights into a novel and potentially effective approach to improve the efficacy of MSC treatment.

Bone marrow mesenchymal stem cells suppress metastatic tumor development in mouse by modulating immune system

Introduction

Bone marrow mesenchymal stem cells (BMSCs) have been studied extensively because of their potential use in clinical therapy, regenerative medicine, and tissue engineering. However, their application in tumor therapy remains yet in preclinical stage because of the distinct results from different researches and vagueness of their functional mechanism. In this study, the influence of BMSCs on tumor growth was observed and the potential mechanism was investigated.

Method

Two animal models, H22 ascitogenous hepatoma in BALb/c mouse and B16-F10 pulmonary metastatic melanoma in C57 mouse, were adopted in experience in vivo and treated with BMSCs by intravenous injection. The percentage of Gr-1⁺CD11b⁺ myeloid-derived suppressor cells (MDSCs) and IFN-γ⁺ T cells were observed in peripheral blood (PB) and bone marrow (BM) by Flow Cytometry. BMSCs were co-cultured in vitro with tumor cells and MDSCs in a tumor conditioned medium separately in order to illustrate the mechanism.

Results

Our results demonstrated that BMSCs treatment caused a delayed tumor growth and a prolonged survival in both tumor models, the homing fraction of BMSCs in BM was 2% - 5% in 24–72 hours after transfusion and the percentage of Gr-1⁺CD11b⁺ MDSCs was downregulated in peripheral blood and BM. Meanwhile, IFN-γ⁺ T lymphocytes in PB increased. In vitro co-culture showed that BMSCs inhibited the induction and proliferation of MDSCs in tumor conditioned medium, whereas they didn’t affect the proliferation of B16-F10 and H22 cells by in vitro co-culture. Both in vivo and in vitro results showed that BMSCs have a systemic suppressive effect on MDSCs.

Conclusion

Our data suggest that BMSCs has suppressive effect on tumor and is feasible to be applied in cancer treatment. BMSCs inhibiting MDSCs induction and proliferation is likely one of the mechanism.

Paracrine factors of human fetal MSCs inhibit liver cancer growth through reduced activation of IGF-1R/PI3K/Akt signaling

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death in the world. The multikinase inhibitor sorafenib only demonstrated marginal improvement in overall survival for advanced disease prompted the search for alternative treatment options. Human mesenchymal stem cells (MSCs) have the ability to home to tumor cells. However, its functional roles on the tumor microenvironment remain controversial. Herein, we showed that conditioned media derived from human fetal MSC (CM-hfMSCs) expressed high level of the insulin growth factor binding proteins IGFBPs and can sequester free insulin-like growth factors (IGFs) to inhibit HCC cell proliferation. The inhibitory effect of IGFBPs on IGF signaling was further evident from the reduction of activated IGF-1R and PI3K/Akt, leading eventually to the induction of cell cycle arrest. We also demonstrated that CM-hfMSCs could enhance the therapeutic efficacy of sorafenib and sunitinib. To the best of our knowledge, this is the first report to show that CM-hfMSCs has a tumor-specific, antiproliferative effect that is not observed with normal human hepatocyte cells and patient-derived matched normal tissues. Our results thus suggest that CM-hfMSCs can provide a useful tool to design alternative/adjuvant treatment strategies for HCC, especially in related function to potentiate the effects of chemotherapeutic drugs.

High expression of MAGE-A9 correlates with unfavorable survival in hepatocellular carcinoma

Melanoma-associated antigens (MAGE)-A9 has been reported to play important roles in the development of human cancers. However, the association between MAGE-A9 expression and the clinicopathological characteristics of hepatocellular carcinoma (HCC) is not well understood. The study was to detect the expression of MAGE-A9 in human HCC and investigate the association between its expression and the clinicopathological characteristics of HCC. Reverse transcription-polymerase chain reaction (RT-PCR), one-step quantitative -PCR (qPCR) and immunohistochemistry (IHC) analyses were performed to characterize the expression of MAGE-A9 in HCC cell lines and tissues. Kaplan-Meier survival and Cox regression analyses were employed to evaluate the prognosis of 100 HCC patients. The results showed that the expression of MAGE-A9 in HCC was significantly higher than that in non-cancerous cells and tissues. Moreover, the expression level of the MAGE-A9 protein in HCC was related to the pathological grade (p = 0.003), portal vein invasion (p = 0.001), distant metastasis (p = 0.022) and TNM stage (p = 0.005). Cox regression analysis further revealed that MAGE-A9 expression is an independent prognostic factor for disease-free survival (p = 0.006) and overall survival (p = 0.022). These data are the first to indicate that MAGE-A9 expression is a valuable prognostic biomarker for HCC and that high MAGE-A9 expression suggests unfavorable survival outcomes in HCC patients.

Multipotent mesenchymal stromal cells in liver cancer: implications for tumor biology and therapy

Remodeling of tumor microenvironment is a hallmark in the pathogenesis of liver cancer. Being a pivotal part of tumor stroma, multipotent mesenchymal stromal cells (MSCs), also known as mesenchymal stem cells (MSCs), are recruited and enriched in liver tumors. Owing to their tumor tropism, MSCs are now emerging as vehicles for anticancer drug/gene delivery against liver cancer. However, the exact impact of MSCs on liver cancer remains elusive, as a variety of effects of these cells that have been reported included a plethora of tumor-promoting effects and anti-oncogenic properties. This review aims to dissect the mechanistic insight regarding this observed discrepancy in different experimental settings of liver cancer. Furthermore, we call for caution using MSCs to treat liver cancer or even premalignant liver diseases, before conclusive evidence for safety and efficacy having been obtained.