Human mesenchymal stem cells inhibit metastasis of a hepatocellular carcinoma model using the MHCC97-H cell line

Role of immunotherapies and stem cell therapy in the management of liver cancer: A comprehensive review

Liver cancer (LC) is the sixth most common disease and the third most common cause of cancer-related mortality. The WHO predicts that more than 1 million deaths will occur from LC by 2030. Hepatocellular carcinoma (HCC) is a common form of primary LC. Today, the management of LC involves multiple disciplines, and multimodal therapy is typically selected on an individual basis, considering the intricate interactions between the patient's overall health, the stage of the tumor, and the degree of underlying liver disease. Currently, the treatment of cancers, including LC, has undergone a paradigm shift in the last ten years because of immuno-oncology. To treat HCC, immune therapy approaches have been developed to enhance or cause the body's natural immune response to specifically target tumor cells. In this context, immune checkpoint pathway inhibitors, engineered cytokines, adoptive cell therapy, immune cells modified with chimeric antigen receptors, and therapeutic cancer vaccines have advanced to clinical trials and offered new hope to cancer patients. The outcomes of these treatments are encouraging. Additionally, treatment using stem cells is a new approach for restoring deteriorated tissues because of their strong differentiation potential and capacity to release cytokines that encourage cell division and the formation of blood vessels. Although there is no proof that stem cell therapy works for many types of cancer, preclinical research on stem cells has shown promise in treating HCC. This review provides a recent update regarding the impact of immunotherapy and stem cells in HCC and promising outcomes.

Signaling crosstalk between mesenchymal stem cells and tumor cells: Implications for tumor suppression or progression

Mesenchymal stem cells (MSCs) have been extensively used in various therapeutic applications over the last two decades, particularly in regenerative medicine and cancer treatment. MSCs have the ability to differentiate into mesodermal and non-mesodermal lineages, which makes them a popular choice in tissue engineering and regenerative medicine. Studies have shown that MSCs have inherent tumor-suppressive properties and can affect the behavior of multiple cells contributing to tumor development. Additionally, MSCs possess a tumor tropism property and have a hypoimmune nature. The intrinsic features of MSCs along with their potential to undergo genetic manipulation and be loaded with various anticancer therapeutics have motivated researchers to use them in different cancer therapy approaches without considering their complex dynamic biological aspects. However, despite their desirable features, several reports have shown that MSCs possess tumor-supportive properties. These contradictory results signify the sophisticated nature of MSCs and warn against the potential therapeutic applications of MSCs. Therefore, researchers should meticulously consider the biological properties of MSCs in preclinical and clinical studies to avoid any undesirable outcomes. This manuscript reviews preclinical studies on MSCs and cancer from the last two decades, discusses how MSC properties affect tumor progression and explains the mechanisms behind tumor suppressive and supportive functions. It also highlights critical cellular pathways that could be targeted in future studies to improve the safety and effectiveness of MSC-based therapies for cancer treatment. The insights obtained from this study will pave the way for further clinical research on MSCs and development of more effective cancer treatments.

Hepatocellular carcinoma patients serum modulates the regenerative capacities of adipose mesenchymal stromal cells

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers causing the highest mortality rate worldwide. Treatment options of surgery, radiation, cytotoxic drugs and liver transplantation suffer significant side effects and a high frequency of relapse. Stem cell therapy has been proposed as a new effective therapy, however, controversial reports are emerging on the role of mesenchymal stem cells in cancer. In this work, we aimed to assess the regenerative capacities of adipose mesenchymal stem cells when exposed to serum from HCC patients, by assessing the effect of the sera on modulating the regenerative capacities of h-AMSCs and the cancer properties in HCC cells. This will pave the way for maximizing the efficacy of MSCs in cancer therapy. Our data show that HCC serum-treated hA-MSCs suffered oncogene-induced senescence as shown by their altered morphology and ameliorated proliferation and differentiation. The cells were enlarged with small irregular nuclei, swollen rough endoplasmic reticulum cisternae, and aging lysosomes typified by dark residual bodies. HCC serum-treated Huh-7 cancer cells on the other hand displayed higher tumor aggressiveness as depicted by altered morphology, increased cellular proliferation and migration, and decreased percentage of early and late apoptotic cells. Our findings provide evidence that exposure of hA-MSCs to the serum of HCC patients decreases their regenerative capacities and should be considered when employed as a potential therapy in HCC patients.

Beyond Canine Adipose Tissue-Derived Mesenchymal Stem/Stromal Cells Transplantation: An Update on Their Secretome Characterization and Applications

A dog is a valuable animal model and concomitantly a pet for which advanced therapies are increasingly in demand. The characteristics of mesenchymal stem/stromal cells (MSCs) have made cell therapy more clinically attractive. During the last decade, research on the MSC therapeutic effectiveness has demonstrated that tissue regeneration is primarily mediated by paracrine factors, which are included under the name of secretome. Secretome is a mixture of soluble factors and a variety of extracellular vesicles. The use of secretome for therapeutic purposes could have some advantages compared to cell-based therapies, such as lower immunogenicity and easy manufacturing, manipulation, and storage. The conditioned medium and extracellular vesicles derived from MSCs have the potential to be employed as new treatments in veterinary medicine. This review provides an update on the state-of-the-art characterization and applications of canine adipose tissue-derived MSC secretome.

Cancer-associated mesenchymal stem/stromal cells: role in progression and potential targets for therapeutic approaches

Malignancies contain a relatively small number of Mesenchymal stem/stromal cells (MSCs), constituting a crucial tumor microenvironment (TME) component. These cells comprise approximately 0.01-5% of the total TME cell population. MSC differentiation potential and their interaction with the tumor environment enable these cells to affect tumor cells' growth, immune evasion, metastasis, drug resistance, and angiogenesis. This type of MSC, known as cancer-associated mesenchymal stem/stromal cells (CA-MSCs (interacts with tumor/non-tumor cells in the TME and affects their function by producing cytokines, chemokines, and various growth factors to facilitate tumor cell migration, survival, proliferation, and tumor progression. Considering that the effect of different cells on each other in the TME is a multi-faceted relationship, it is essential to discover the role of these relationships for targeting in tumor therapy. Due to the immunomodulatory role and the tissue repair characteristic of MSCs, these cells can help tumor growth from different aspects. CA-MSCs indirectly suppress antitumor immune response through several mechanisms, including decreasing dendritic cells (DCs) antigen presentation potential, disrupting natural killer (NK) cell differentiation, inducing immunoinhibitory subsets like tumor-associated macrophages (TAMs) and Treg cells, and immune checkpoint expression to reduce effector T cell antitumor responses. Therefore, if these cells can be targeted for treatment so that their population decreases, we can hope for the treatment and improvement of the tumor conditions. Also, various studies show that CA-MSCs in the TME can affect other vital aspects of a tumor, including cell proliferation, drug resistance, angiogenesis, and tumor cell invasion and metastasis. In this review article, we will discuss in detail some of the mechanisms by which CA-MSCs suppress the innate and adaptive immune systems and other mechanisms related to tumor progression.

Multiple Dimensions of using Mesenchymal Stem Cells for Treating Liver Diseases: From Bench to Beside

Liver diseases impose a huge burden worldwide. Although hepatocyte transplantation has long been considered as a potential strategy for treating liver diseases, its clinical implementation has created some obvious limitations. As an alternative strategy, cell therapy, particularly mesenchymal stem cell (MSC) transplantation, is widely used in treating different liver diseases, including acute liver disease, acute-on-chronic liver failure, hepatitis B/C virus, autoimmune hepatitis, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, alcoholic liver disease, liver fibrosis, liver cirrhosis, and hepatocellular carcinoma. Here, we summarize the status of MSC transplantation in treating liver diseases, focusing on the therapeutic mechanisms, including differentiation into hepatocyte-like cells, immunomodulating function with a variety of immune cells, paracrine effects via the secretion of various cytokines and extracellular vesicles, and facilitation of homing and engraftment. Some improved perspectives and current challenges are also addressed. In summary, MSCs have great potential in the treatment of liver diseases based on their multi-faceted characteristics, and more accurate mechanisms and novel therapeutic strategies stemming from MSCs will facilitate clinical practice.

The Modulatory Effect of Adipose-Derived Stem Cells on Endometrial Polyp Fibroblasts

Endometrial polyps (EPs) are benign overgrowths of the endometrium, with the potential to cause severe complications, ranging from discomfort to inflammation and infertility. Dysfunction of endometrial fibroblasts may be a critical component leading to the development of polyps. While surgical intervention is the common remedy for severe cases, it comes with drawbacks, including infection, bleeding, and risk of damage to the cervix and adjacent tissues. Adipose-derived mesenchymal stromal cells (ASCs) are at the focus of modern medicine, as key modulators of tissue homeostasis, inflammation and tissue repair, rendering them prime candidate agents for tissue regeneration and cell-based therapies. In the current work, endometrial polyps were isolated from patients admitted to the OB/GYN department at the Galilee Medical Center and extracted fibroblasts (EPFs) were isolated and characterized. ASCs were isolated from healthy patients. The effect of EPF- and ASC-conditioned media (CM) on polyp-derived fibroblasts was evaluated, in both 2D and 3D assays, as well as on the expression of matrix-related gene expression. Herein, EPFs exposed to ASC-CM exhibited reduced migration, invasion, contraction of hydrogels, and extracellular matrix deposition, compared to those exposed to EPF-CM. Altogether, the current work suggests that ASCs may have a modulating effect on fibroblasts involved in forming endometrial polyps and may serve as the basis for conservative treatment strategies aimed at treating severe cases of EPs.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles as Biological Carriers for Drug Delivery in Cancer Therapy

Cancer is the second leading cause of death worldwide, with 10.0 million cancer deaths in 2020. Despite advances in targeted therapies, some pharmacological drawbacks associated with anticancer chemo and immunotherapeutic agents include high toxicities, low bioavailability, and drug resistance. In recent years, extracellular vesicles emerged as a new promising platform for drug delivery, with the advantage of their inherent biocompatibility and specific targeting compared to artificial nanocarriers, such as liposomes. Particularly, mesenchymal stem/stromal cells were proposed as a source of extracellular vesicles for cancer therapy because of their intrinsic properties: high in vitro self-renewal and proliferation, regenerative and immunomodulatory capacities, and secretion of extracellular vesicles that mediate most of their paracrine functions. Moreover, extracellular vesicles are static and safer in comparison with mesenchymal stem/stromal cells, which can undergo genetic/epigenetic or phenotypic changes after their administration to patients. In this review, we summarize currently reported information regarding mesenchymal stem/stromal cell-derived extracellular vesicles, their proper isolation and purification techniques - from either naive or engineered mesenchymal stem/stromal cells - for their application in cancer therapy, as well as available downstream modification methods to improve their therapeutic properties. Additionally, we discuss the challenges associated with extracellular vesicles for cancer therapy, and we review some preclinical and clinical data available in the literature.

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.

The role of mesenchymal stem cells in the occurrence, development, and therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common type of liver malignant tumor, with high recurrence and mortality rates. Mesenchymal stem cells (MSCs) are multipotent cells that can be recruited into the tumor microenvironment (TME). What is known, TME plays a vital part in tumor progression. In recent years, accumulating studies have found that MSCs have a dual role of promotion and inhibition in the occurrence and development of HCC. In this review, we analyzed the role of MSCs in TME and summarized the relationship between MSCs and liver cancer stem cells, the molecular signaling pathway mechanisms of MSCs promoting and inhibiting HCC, and the latest research progress of MSCs in the treatment of HCC.

Local drug delivery system for the treatment of tongue squamous cell carcinoma in rats

The present study describes a local drug delivery system with two functions, which can suppress tumor growth and accelerate wound healing. Thе system consists of a two-layer multicomponent fibrin-based gel (MCPFTG). The internal layer of MCPFTG, which is in direct contact with the wound surface, contains cisplatin placed on a CultiSpher-S collagen microcarrier. The external layer of MCPFTG consists of a CultiSpher-S microcarrier with lyophilized bone marrow stem cells (BMSCs). The efficacy of MCPFTG was evaluated in a rat model of squamous cell carcinoma of the tongue created with 4-nitroquinoline 1-oxide. The results of the study showed that, within 20–25 days, a non-healing wound of the tongue was formed in animals that underwent only 85% resection of squamous cell carcinoma, while rapid progression of the residual tumor was concomitantly observed. Immunohistochemical methods revealed high expression of cyclin D1 and low expression of E-cadherin in these animals. Additionally, high expression of p63 and Ki-67 was noted. In 80% of animals with squamous cell carcinoma of the tongue that were treated with MCPFTG after 85% tumor resection, a noticeable suppression of tumor growth was evident throughout 150 days, and tumor recurrence was not detected. Immunohistochemistry revealed low or moderate expression of cyclin D1, and high expression of E-cadherin throughout the whole observation period. The MCPFTG-based local drug delivery system was shown to be effective in suppressing tumor growth and preventing recurrence. MCPFTG decreased the toxicity of cisplatin and enhanced its antitumor activity. In addition, lyophilized paracrine BMSC factors present in MCPFTG accelerated wound healing after tumor removal. Thus, the present study suggests novel opportunities for the development of a multifunctional drug delivery system for the treatment of squamous cell carcinoma.

Assessing the effect of human mesenchymal stem cell-derived conditioned media on human cancer cell lines: A systematic review

BACKGROUND

Mesenchymal stem cells (MSCs) exhibit differential effect (augmentation or inhibition) on cancer cells depending on the tissue of origin. Given the increasing demand to use MSCs in regenerative medicine, it is vital to ensure that the MSCs being employed are not pro-carcinogenic.

OBJECTIVE

To assess the effect of human MSC derived conditioned media (CM) on human cancer cell lines.

MATERIALS AND METHODS

PubMed, SCOPUS, and Web of Science were searched using the keyword combination 'human mesenchymal stem cell and conditioned media and human cancer cell line and in-vitro'.

RESULTS

MSC-CM pro-carcinogenic molecules were IL-6, IL-8, FGF10, VEGF, PDGF, TGF-b1, IGF-1, GRO-a, OSP, MMPs, TNFα, IL-4, IL-10, IL-13, IL-17, IL-1 β, G-CSF, MCP‑1, MIP‑1α, MIP‑1β, RANTES, MIG, IP‑10, HGFa, ETX, DKK1; anti-carcinogenic molecules were IFN-β, OST, LIGHT, FRTK3, INF-γ, IP-10, LAP, IL‑1RA, IL‑2, IL-5, IL-7, IL-12, IL-15, IFN-α, IFN‑γ. Effector pathways were STAT 1, JAK2/STAT3, Ras-Raf-MEK-ERK, Wnt/β-catenin, NF-κB, ERK1/2, PI3K/ Akt/mTOR, MAPK/ERK. BMSC, ADMSC, UCMSC, WJMSC DPMSC, AMSC, and UTCMSC had a differential effect on carcinogenesis. GMSC, LMSC, FDMSC were anti-carcinogenic. OMSC was pro-carcinogenic.

CONCLUSION

Use of MSC-CM with a pro-carcinogenic effect must be restricted in cancer patients irrespective of the nature of the application.

Bie Jia Jian pill enhances the amelioration of bone mesenchymal stem cells on hepatocellular carcinoma progression

Background

The therapeutic efficiency of Traditional Chinese Medicine (TCM) in suppressing the recurrence and metastasis of hepatocellular carcinoma (HCC) has been well proved.

Objective

The aim of this study is to investigate the role of Bie Jia Jian pill (BJJP) combined with bone mesenchymal stem cells (BMSCs) in HCC progression.

Methods

Flow cytometry was used to identify BMSCs isolated from BALB/c mice. The expressions of biomarkers and apoptosis rate of cancer stem cells (CSCs) enriched from Huh7 cells were also measured. The osteogenic differentiation and adipogenic differentiation ability of isolated BMSCs was determined by oil red O staining and Alizarin Red Staining. CSCs were used to establish the orthotopic HCC model. Histological changes in the liver tissues were examined by hematoxylin–eosin (H&E) staining and Van Gieson (VG) staining. The cell apoptotic rate in the cancer tissues was detected by TUNEL staining. The cell proliferation antigen Ki67 in the cancer tissues were detected by immunofluorescence assay and PCR, respectively. The levels of CSCs cellular surface markers (CD24, CD133 and EpCAM) and Wnt/β-catenin signal pathway related proteins were detected by PCR and western blot.

Results

Treatment of BJJP or BMSCs both improved the morphology induced by HCC and suppressed the differentiation ability of CSCs, as evidenced by down-regulated expressions of CD24, CD133, EpCAM and Ki67. The protective effect of BJJP or BMSCs in cancer tissues can be enhanced by the combination of BJJP and BMSCs. In addition to that, BJJP or BMSCs alone was found to increase the expression of miR-140 and promote cell apoptosis in CSCs, while down-regulation of miR-140 partially reversed the protective effect of BMSCs or BJJP + BMSCs on cancer tissues. BJJP + BMSCs treatment together also can down-regulate the expressions of Wnt3a and β-catenin.

Conclusions

These results proved the inhibitory role of BJJP + BMSCs in HCC development through regulating miR-140 and Wnt/β-catenin signal pathway.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11418-021-01548-4.

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.

Translational Animal Models Provide Insight Into Mesenchymal Stromal Cell (MSC) Secretome Therapy

The therapeutic potential of the mesenchymal stromal cell (MSC) secretome, consisting of all molecules secreted by MSCs, is intensively studied. MSCs can be readily isolated, expanded, and manipulated in culture, and few people argue with the ethics of their collection. Despite promising pre-clinical studies, most MSC secretome-based therapies have not been implemented in human medicine, in part because the complexity of bioactive factors secreted by MSCs is not completely understood. In addition, the MSC secretome is variable, influenced by individual donor, tissue source of origin, culture conditions, and passage. An increased understanding of the factors that make up the secretome and the ability to manipulate MSCs to consistently secrete factors of biologic importance will improve MSC therapy. To aid in this goal, we can draw from the wealth of information available on secreted factors from MSC isolated from veterinary species. These translational animal models will inspire efforts to move human MSC secretome therapy from bench to bedside.

Human and mouse melanoma cells recapitulate an EMT-like program in response to mesenchymal stromal cells secretome

The mechanisms underlying the propensity of melanomas to metastasize are not completely understood. We hypothesized that melanoma cells are capable of promptly activating an epithelial-to-mesenchymal transition (EMT)-like profile in response to stroma-derived factors. Thus, we investigated the role of mesenchymal stromal cells (MSCs), a cell population considered as a precursor of tumor stroma, on the activation of an EMT-like profile and acquisition of metastatic traits in melanoma cells. After subcutaneous co-injection with mouse B16 melanoma cells, MSCs occupied perivascular sites within tumors and enhanced B16 metastasis to the lungs. In vitro, MSCs' secretome activated an EMT-like profile in B16 cells, reducing their avidity to fibronectin, and increasing their motility and invasiveness. These effects were abrogated upon blocking of MET phosphorylation in B16 cells using small molecule inhibitors. MSCs also activated an EMT-like profile in human melanoma cells from different stages of progression. Activation of EMT in human cells was associated with increased levels of p-STAT1 and p-STAT3. In conclusion, both mouse and human melanoma cells are equipped to activate an EMT-like program and acquire metastatic traits through the activation of distinct pathways by MSCs' secretome.

The effect of bone marrow mesenchymal stem cells on highly metastatic MHCC97-H hepatocellular carcinoma cells following OPN and TGFβ1 gene silencing

The metastatic behavior of hepatocellular carcinoma (HCC) is one of the key factors that leads to poor prognosis. The aim of the current study was to determine the changes in metastasis and the proliferation potential of bone marrow mesenchymal stem cells (BMSCs) in high metastatic potential hepatocellular carcinoma (MHCC97-H) following gene silencing. The osteopontin (OPN) and transforming growth factor-β (TGFβ₁ ) genes, which are associated with metastasis and tumor proliferation, were silenced in MHCC97-H cells. Transwell assays were used to evaluate the migration of MHCC97-H cells in vitro. Additionally, a murine model of MHCC97-H lung metastasis was established. Following OPN and TGFβ₁ silencing, the migration of MHCC97-H cells was significantly reduced following BMSC intervention (P<0.01). Furthermore, there were few MHCC97-H cells in the lung tissues of the OPN- and TGFβ₁ -silenced animals, and their integrated optical density (IOD) value was significantly lower compared with controls (P<0.05). Immunofluorescence of lung metastasis in the MHCC97-H model revealed that there was no significant difference in the IOD value of integrin α_vβ₃ expression in the OPN- and TGFβ₁ -silenced groups compared with controls (P>0.05). The metastasis and proliferation potential of MHCC97-H following BMSC intervention were significantly reduced in vitro and in vivo, especially in the TGFβ₁-silenced group. The decrease in the metastatic potential in gene-silenced MHCC97-H cells was not associated with integrin α_vβ₃ expression. Therefore, OPN and TGFβ₁ may be potential targets for HCC treatment, and TGFβ₁ may have a higher therapeutic potential for BMSC intervention.

Sorafenib and Mesenchymal Stem Cell Therapy: A Promising Approach for Treatment of HCC

Hepatocellular carcinoma (HCC) is the fifth most commonly diagnosed cancer and the second most common cause of cancer-related death worldwide. Sorafenib (Sora) is used as a targeted therapy for HCC treatment. Mesenchymal stem cells (MSCs) are applied as a new approach to fight malignancies. Drug resistance and side effects are the major concerns with Sora administration. The effect of using the combination of sorafenib and MSCs on tumor regression in xenograft HCC models was evaluated in this study. Methods and Materials. Human hepatocellular carcinoma cell lines (HepG2) were subcutaneously implanted into the flank of 18 nude mice. The animals were randomly divided into six groups (n = 3); each received Sora (oral), MSCs (IV injection), MSCs (local injection), Sora + MSCs (IV injection), Sora + MSCs (local injection), or no treatment (the control group). Six weeks after tumor implantation, the mice were scarified and tumoral tissues were resected in their entirety. Histopathological and immunohistochemical evaluations were used to measure tumor proliferation and angiogenesis. Apoptotic cells were quantified using the TUNEL assay. Results. No significant difference was found in the tumor grade among the treatment groups. Differentiation features of the tumoral cells were histopathologically insignificant in all the groups. Tumor necrosis was highest in the hpMSC (local) + Sora group. Tumor cell proliferation was reduced in hpMSC (local) + Sora-treated and hpMSC (IV) + Sora-treated mice compared with the other groups. Apoptotic-positive cells occupied a greater proportion in the Sora, hpMSC (IV) + Sora, and hpMSC (local) + Sora groups. Conclusion. A combination of chemotherapy and MSC can yield to more favorable results in the treatment of HCC.

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.

Efficacy of mesenchymal stem cells in the treatment of gastrointestinal malignancies

Mesenchymal stem cells (MSCs), which are a kind of stem cell, possess an immune privileged nature, tumour homing features, and multi-lineage differentiation ability. MSCs have been studied in many fields, such as tissue engineering, nervous system diseases, and cancer treatment. In recent years, an increasing number of researchers have focused on the effects of MSCs on various kinds of tumours. However, the concrete anticancer efficacy of MSCs is still controversial. Gastrointestinal (GI) malignancies are the major causes of cancer-related death worldwide. The interactions of MSCs and GI cancer cells in specific conditions have attracted increasing attention. In this review, we introduce the characteristics of MSCs and analyse the effects of MSCs on GI malignancies, including gastric cancer, hepatoma, pancreatic cancer, and colorectal cancer. In addition, we also provide our perspectives on why MSCs may play different roles in GI malignancies and further research directions to increase the treatment efficacy of MSCs on GI malignancies.

Research Progress in Liver-Regenerating Microenvironment and DNA Methylation in Hepatocellular Carcinoma: The Role of Traditional Chinese Medicine

The development, progression, recurrence, and metastasis of hepatocellular carcinoma (HCC) are closely associated with an abnormal liver-regenerating microenvironment (LRM). Therefore, preventing and reversing an abnormal LRM is a potential therapeutic strategy against HCC. Studies are increasingly focusing on the impact of regeneration, fibrosis, angiogenesis, inflammation, immunomodulation, and hepatic stem cells on HCC development and progression. As a key epigenetic mechanism, DNA methylation is extensively involved in regulating physiological and pathological pathways. In this review, we summarize recent findings on the role of DNA methylation in the fibrotic, angiogenic, inflammatory/immune, and stem cell microenvironments of HCC, and discuss new advances in Traditional Chinese Medicine (TCM) on influencing the abnormal LRM, so as to gain new insights into alleviating the abnormal LRM via regulating DNA methylation by TCM.

Stem Cell Therapy for Hepatocellular Carcinoma: Future Perspectives

Hepatocellular carcinoma (HCC) is one of the most common types of cancer and results in a high mortality rate worldwide. Unfortunately, most cases of HCC are diagnosed in an advanced stage, resulting in a poor prognosis and ineffective treatment. HCC is often resistant to both radiotherapy and chemotherapy, resulting in a high recurrence rate. Although the use of stem cells is evolving into a potentially effective approach for the treatment of cancer, few studies on stem cell therapy in HCC have been published. The administration of stem cells from bone marrow, adipose tissue, the amnion, and the umbilical cord to experimental animal models of HCC has not yielded consistent responses. However, it is possible to induce the apoptosis of cancer cells, repress angiogenesis, and cause tumor regression by administration of genetically modified stem cells. New alternative approaches to cancer therapy, such as the use of stem cell derivatives, exosomes or stem cell extracts, have been proposed. In this review, we highlight these experimental approaches for the use of stem cells as a vehicle for local drug delivery.

Mesenchymal stromal cells induce inhibitory effects on hepatocellular carcinoma through various signaling pathways

Hepatocellular carcinoma (HCC) is the most prevalent type of malignant liver disease worldwide. Molecular changes in HCC collectively contribute to Wnt/β-catenin, as a tumor proliferative signaling pathway, toll-like receptors (TLRs), nuclear factor-kappa B (NF-κB), as well as the c-Jun NH2-terminal kinase (JNK), predominant signaling pathways linked to the release of tumor-promoting cytokines. It should also be noted that the Hippo signaling pathway plays an important role in organ size control, particularly in promoting tumorigenesis and HCC development. Nowadays, mesenchymal stromal cells (MSCs)-based therapies have been the subject of in vitro, in vivo, and clinical studies for liver such as cirrhosis, liver failure, and HCC. At present, despite the importance of basic molecular pathways of malignancies, limited information has been obtained on this background. Therefore, it can be difficult to determine the true concept of interactions between MSCs and tumor cells. What is known, these cells could migrate toward tumor sites so apply effects via paracrine interaction on HCC cells. For example, one of the inhibitory effects of MSCs is the overexpression of dickkopf-related protein 1 (DKK-1) as an important antagonist of the Wnt signaling pathway. A growing body of research challenging the therapeutic roles of MSCs through the secretion of various trophic factors in HCC. This review illustrates the complex behavior of MSCs and precisely how their inhibitory signals interface with HCC tumor cells.

Human mesenchymal stem cells promote tumor growth via MAPK pathway and metastasis by epithelial mesenchymal transition and integrin α5 in hepatocellular carcinoma

Mesenchymal stem cells (MSCs) appear to be a potential vehicle for anticancer drugs due to their excellent tumor tropism ability. However, the interactions between MSCs and hepatocellular carcinoma (HCC) are quite controversial and the underlying mechanisms are ambiguous. In this study, an investigation was conducted into the effect of human MSCs (hMSCs) on tumor proliferation and metastasis both in xenograft and orthotopic models. It was discovered that hMSCs could promote tumor growth though activating mitogen-activated protein kinase (MAPK) signaling pathway and promote metastasis by epithelial mesenchymal transition (EMT) in vivo. To test whether hMSCs could induce immunosuppressive effects, the expression of the Natural killer (NK) cell marker CD56 was measured by immunohistochemical staining and the expression of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were measured by qRT-PCR. It was found out that CD56 expression significantly decreased, while TNF-α and IL-6 expression increased in the hMSCs-treated tissues. Mechanistically, RNA sequencing was performed, which led to a discovery that integrin α5 (ITGA5) was over-expressed in hMSCs-treated HCC. ITGA5 siRNAs blocked the hMSCs-induced migration and invasion of HCC, while over-expression of ITGA5 promoted the migration and invasion ability in HCC-hMSCs, indicating that the expression of ITGA5 is associated with hMSCs-induced tumor metastasis. These findings suggest that hMSCs may play a vital role in HCC proliferation and metastasis and could be identified as a putative therapeutic target in HCC.

Effect of adipose-derived mesenchymal stem cells on hepatocellular carcinoma: In vitro inhibition of carcinogenesis

AIM

To investigate the effect of adipose-derived mesenchymal stem cells (ADMSCs) and their conditioned media (CM) on hepatocellular carcinoma (HCC) cell tumorigenesis.

METHODS

The proliferation rate of HepG2 and PLC-PRF-5 HCC cancer cells was measured using the trypan blue exclusion method and confirmed using the cell-counting kit 8 (commonly known as CCK-8) assay. Apoptosis was detected by flow cytometry using annexin V-FITC. Protein and mRNA expression was quantified by ELISA and real time PCR, respectively. Migration and invasion rates were performed by Transwell migration and invasion assays. Wound healing was examined to confirm the data obtained from the migration assays.

RESULTS

Our data demonstrated that when co-culturing HCC cell lines with ADMSCs or treating them with ADMSC CM, the HCC cell proliferation rate was significantly inhibited and the apoptosis rate increased. The decreased proliferation rate was accompanied by an upregulation of P53 and Retinoblastoma mRNA and a downregulation of c-Myc and hTERT mRNA levels. More notably, ADMSCs and their CM suppressed the expression of the two important markers of HCC carcinogenicity, alpha-fetoprotein and Des-gamma-carboxyprothrombin. In addition, the migration and invasion levels of HepG2 and PLC-PRF-5 cells significantly decreased, potentially through increased expression of the tissue inhibitor metalloproteinases TIMP-1, TIMP-2 and TIMP-3.

CONCLUSION

These findings shed new light on a protective and therapeutic role for ADMSCs and their CM in controlling HCC invasiveness and carcinogenesis.

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 cell-based drug delivery strategy: from cells to biomimetic

Owing to the diversity and ease of preparation of nanomaterials, the rational nanocarriers with a rational design have become increasingly popular in medical researches. Although nanoparticle-based drug delivery exhibits great potential, there are some challenges facing like rapid plasma clearance, triggering or aggravation of immune response, etc. Herein, cell-based targeted drug delivery systems have drawn more and more attention owing to low immunogenicity and intrinsic mutation rate, and innate ability to allow targeted delivery. Mesenchymal stem cells (MSCs) have been used in gene and drug delivery. The use of MSCs is a promising approach for the development of gene transfer systems and drug loading strategies because of their intrinsic properties, including homing ability and tumor tropism. By combining the inherent cell properties and merits of synthetic nanoparticles (NPs), cell membrane coated NPs emerge as the time requires. Overall, we provide a comprehensive overview of the utility of MSCs in drug and gene delivery as well as MSC membrane coated nanoparticles for therapy and drug delivery, aiming to figure out the significant room for development and highlight the potential future directions.

Combination therapy of sorafenib with mesenchymal stem cells as a novel cancer treatment regimen in xenograft models of hepatocellular carcinoma

AIM

Hepatocellular carcinoma (HCC) is the most common liver malignancy and the second leading cause of cancer-related deaths in the world. Sorafenib is the first-line treatment of HCC. Although sorafenib has positive effects on the survival of patients, novel therapeutic strategies are needed to extend survival and improve the efficacy of sorafenib. This study combines sorafenib with mesenchymal stem cells (MSCs) as a new approach to enhance the efficacy of sorafenib.

MATERIAL AND METHODS

A subcutaneous xenograft model of HCC, established by human HepG2 cell lines, was implanted into the flank of nude mice and was used to evaluate tumor growth after treatment with sorafenib alone or in combination with MSCs. The aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, and creatinine levels were measured for safety assessment. Histopathological studies were performed using hematoxylin and eosin staining, and immunohistochemistry tests were performed to evaluate proliferation (Ki67) and angiogenesis (CD34). The TUNEL assay was used to detect apoptosis and measure the expression of major inflammatory cytokines (IL-1a, IL-10, and TNF-α) with real-time polymerase chain reaction.

RESULT

Sorafenib, in combination with MSCs, strongly inhibited tumor growth in the xenograft model. Furthermore, the combination therapy significantly inhibited HCC cell proliferation, decreased tumor angiogenesis, and induced apoptosis and maintained antitumor-associated anti-inflammatory effects of MSCs.

CONCLUSION

This combination therapy strategy could be used as a new therapeutic approach to the treatment of HCC that significantly improves upon the results achieved using sorafenib as monotherapy.

Effects of mesenchymal stem cells on solid tumor metastasis in experimental cancer models: a systematic review and meta-analysis

Background

It has been reported mesenchymal stem cells (MSCs) are recruited to and become integral parts of the tumor microenvironment. MSCs might have an active role in solid tumor progression, especially cancer metastasis. However, the contribution of MSCs in the process of cancer metastasis is still controversial. In this review, we performed a meta-analysis on the effects of MSCs administration on cancer metastasis based on published preclinical studies.

Methods

The PRISMA guidelines were used. A total of 42 publications met the inclusion criteria. Outcome data on the incidence and the number of cancer metastasis as well as study characteristics were extracted. Quality of the studies was assessed according to SYRCLE Risk of Bias tool. Random-effects meta-analysis was used to pool estimates.

Results

Of the 42 studies included, 32 reported that MSCs administration promoted outcome events (numbers or incidences of cancer metastasis), and 39 reported data suitable for meta-analysis. The median effect size (RR) was 2.04 for the incidence of cancer metastasis (95% CI 1.57–2.65, I² = 21%), and the median effect size (SMD) was 1.23 for the number of cancer metastasis (95% CI 0.43–2.03, I² = 89%). Heterogeneity was observed, with the greater impact based on study length and different ways of metastasis measurement and MSCs administration.

Conclusion

Our results suggested MSCs administration increased the number and the incidence of cancer metastasis in experimental cancer models. High heterogeneity and poor reported risk of bias limit the quality of these findings. Further preclinical studies with better design and adequate reporting are still needed.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1484-9) contains supplementary material, which is available to authorized users.

Impact of Mesenchymal Stem Cells and Vitamin D on Transforming Growth Factor Beta Signaling Pathway in Hepatocellular Carcinoma in Rats

Background:

Transforming growth factor-beta (TGF-β) signaling is recognized as being critical for carcinogenesis. Vitamin D has proved to exert numerous tumor suppressive effects. Effects of bone marrow derived mesenchymal stem cells (BM-MSCs) on tumor progression are still controversial. The present study was conducted to evaluate the effects of BM-MSCs and vitamin D on TGF-β signaling in an experimental hepatocellular carcinoma (HCC) model in rats.

Materials and Methods:

The study was conducted on fifty female white albino rats divided equally into 5 groups: controls, HCC induced by diethyl-nitrosamine (DENA) and carbon tetrachloride (CCl4), HCC plus MSCs, HCC plus vitamin D and HCC plus both MSCs and vitamin D. The following parameters were assessed in rat liver tissues: TGF-β and Smad2 protein levels by ELISA and western blotting, respectively, gene expression of Smad3, Smad7, Snail, HNF4α and MMP-2 and histopathological lesions. Serum levels of alpha fetoprotein (AFP), ALT and albumin were also assessed.

Results:

TGF-β protein levels and gene expression of its downstream effectors (Smad3 and Snail), in addition to Smad2 protein levels were significantly higher in the HCC group than in the control group. On the other hand, they were significantly down-regulated in all treated groups with most significant amelioration with both MSCs and vitamin D. Also, the serum levels of AFP were significantly increased in the untreated HCC group, and this was again reversed in all treated groups. Histopathological examination of liver tissue revealed that administration of MSCs or vitamin D into HCC rat group improved the histopathological picture with residual tumor pathology, while administration of both MSCs and vitamin D showed better restoration of liver parenchyma. These data suggest that the TGF-β signaling pathway could be used as a therapeutic target in HCC.

Soluble factors from adipose tissue-derived mesenchymal stem cells promote canine hepatocellular carcinoma cell proliferation and invasion

The potential effects of adipose tissue-derived mesenchymal stem cells (AT-MSCs) on the growth and invasion of canine tumours including hepatocellular carcinoma (HCC) are not yet understood. Moreover in humans, the functional contribution of AT-MSCs to malignancies remains controversial. The purpose of this study was to investigate the effects of AT-MSCs on the proliferation and invasion of canine HCC cells in vitro. The effect of AT-MSCs on mRNA levels of factors related to HCC progression were also evaluated. Conditioned medium from AT-MSCs (AT-MSC-CM) significantly enhanced canine HCC cell proliferation and invasion. Moreover, mRNA expression levels of transforming growth factor-beta 1, epidermal growth factor A, hepatocyte growth factor, platelet-derived growth factor-beta, vascular endothelial growth factor, and insulin-like growth factor 2 were 2.3 ± 0.4, 2.0 ± 0.5, 5.7 ± 1.9, 1.7 ± 0.2, 2.1 ± 0.4, and 1.4 ± 0.3 times higher, respectively (P < 0.05). The mRNA expression level of MMP-2 also increased (to 4.0 ± 1.2 times control levels) in canine HCC cells co-cultured with AT-MSCs, but MMP-9 mRNA significantly decreased (to 0.5 ± 0.1 times control levels). These findings suggest that soluble factors from AT-MSCs promote the proliferation and invasion of canine HCC cells.

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.

Tropism of liver epithelial cells toward hepatocellular carcinoma in vitro and in vivo with altering gene expression of cancer stem cells

BACKGROUND

Rat liver epithelial (RLE) cells could inhibit the proliferation and invasiveness of hepatoma cells in vitro. This study is to understand the tropism and the effect of RLE cells on mouse hepatoma cells both in vitro and in vivo.

METHODS

RLE cells were isolated from new-born rats and characterized their stem cell markers. Co-culture and HCC mouse model was established to detect therapeutic effect of RLE cells.

RESULTS

RLE cells (including Thy-1⁺ RLE cells, Thy-1^- RLE cells, RLE cells) displayed a selective tropism toward ML-1 hepatoma cells both in vitro and in vivo. They altered the gene expression of some cancer stem cell markers in the liver tumor.

CONCLUSION

Liver epithelial cells have a selective tropism toward HCC in vitro and in vivo. They could alter the gene expression of cancer stem cells.

Concise Review: Cancer Cells, Cancer Stem Cells, and Mesenchymal Stem Cells: Influence in Cancer Development

Tumors are composed of different types of cancer cells that contribute to tumor heterogeneity. Among these populations of cells, cancer stem cells (CSCs) play an important role in cancer initiation and progression. Like their stem cells counterpart, CSCs are also characterized by self-renewal and the capacity to differentiate. A particular population of CSCs is constituted by mesenchymal stem cells (MSCs) that differentiate into cells of mesodermal characteristics. Several studies have reported the potential pro-or anti-tumorigenic influence of MSCs on tumor initiation and progression. In fact, MSCs are recruited to the site of wound healing to repair damaged tissues, an event that is also associated with tumorigenesis. In other cases, resident or migrating MSCs can favor tumor angiogenesis and increase tumor aggressiveness. This interplay between MSCs and cancer cells is fundamental for cancerogenesis, progression, and metastasis. Therefore, an interesting topic is the relationship between cancer cells, CSCs, and MSCs, since contrasting reports about their respective influences have been reported. In this review, we discuss recent findings related to conflicting results on the influence of normal and CSCs in cancer development. The understanding of the role of MSCs in cancer is also important in cancer management. Stem Cells Translational Medicine 2017;6:2115-2125.

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.

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.

Mesenchymal stem cells in inflammatory microenvironment potently promote metastatic growth of cholangiocarcinoma via activating Akt/NF-κB signaling by paracrine CCL5

Our previous work has demonstrated that mesenchymal stem cells (MSCs) could induce metastatic growth of the inflammation-related cholangiocarcinoma (CCA). However, the functional mechanism of MSCs on CCA progression in the early inflammatory microenvironment remained undetermined. Here, we showed that TNF-α and IFN-γ-induced inflammatory microenvironment stimulated the expression of TNF-α, CCL5, IL-6, IDO, and activated the NF-κB signaling with p65 nuclear translocation in MSCs cells. CCA cell lines QBC939 and Mz-chA-1 exposed to the conditioned medium of MSCs after being stimulated by TNF-α and IFN-γ (TI-CM) exhibited enhanced mobility. Moreover, MSCs pre-stimulated by both inflammatory cytokines (TI-MSCs) increased tumor metastasis in vivo. The conditioned medium of TI-MSCs stimulated the transcription of snail, slug, ZEB1 and ZEB2. Next, the expression of CCL5 of TI-MSCs was verified by ELISA, which indicated that MSCs contributed to CCA migration and metastasis in a paracrine fashion. CCA cells treated with TI-CM up-regulated CCA chemokine receptors, especially CCR5; CCL5 neutralizing antibody or CCR5 inhibitor Maraviroc inhibited the effects of MSCs on CCA cells migration. We also found that Akt/NF-κB signaling was activated by CCL5/CCR5 axis, which increased the expression of MMP2, MMP9. Together, these findings suggest that MSCs in tumor inflammatory microenvironment are elicited of CCL5, which activate AKT/NF-κB signaling and lead to metastatic growth of CCA cells.

Human mesenchymal stem cells preferentially migrate toward highly oncogenic human hepatocellular carcinoma cells with activated EpCAM signaling

The epithelial cell adhesion molecule (EpCAM) is a type I transmembrane glycoprotein that is regarded as one of the markers for tumor initiating cells (TIC) in human hepatocellular carcinoma (HCC). Much work has been directed towards targeting these TICs as a mean of placing these master regulators of cell proliferation and drug resistance under control. Human bone marrow-derived mesenchymal stem cells are known to exhibit an innate property of tumor tropism. However, the possible relationship between MSC and TIC is not well understood. In this study, we show that MSC migration to HCC can be effectively inhibited by TACE and γ-secretase inhibitors that stop the activation of EpCAM signaling event. Silencing of EpCAM expression through siRNA and antibody approaches also resulted in impaired MSC migration. By contrast, increase levels of EpICD proteins in HCC cells and HCC mouse xenografts resulted in enhanced MSC migration. Taken together, these findings show that MSC is drawn to the more oncogenic population of HCC, and could potentially serve as a cell-based carrier of therapeutic genes to target EpICD-enriched hepatic tumor cells.

Co-culture of hepatoma cells with hepatocytic precursor (stem-like) cells inhibits tumor cell growth and invasion by downregulating Akt/NF-κB expression

Hepatocytic stem cells (HSCs) have inhibitory effects on hepatocarcinoma cells. The present study investigated the effects of HSC activity in hepatocarcinoma cells in vitro. A Transwell co-culture system of hepatocytic precursor (stem-like) WB-F344 cells and hepatoma CBRH-7919 cells was used to assess HSC activity in metastasized hepatoma cells in vitro. Nude mouse xenografts were used to assess HSC activity in vivo. Co-culture of hepatoma CBRH-7919 cells with WB-F344 cells suppressed the growth and colony formation, tumor cell migration and invasion capacity of CBRH-7919 cells. The nude mouse xenograft assay demonstrated that the xenograft size of CBRH-7919 cells following co-culture with WB-F344 cells was significantly smaller compared with that of control cells. Furthermore, the expression levels of the epithelial markers E-cadherin and β-catenin were downregulated, while the mesenchymal markers α-SMA and vimentin were upregulated. Co-culture of CBRH-7919 cells with WB-F344 cells downregulated NF-κB and phospho-Akt expression. In conclusion, hepatocytic precursor (stem-like) WB-F344 cells inhibited the growth, colony formation and invasion capacity of metastasized hepatoma CBRH-7919 cells in vitro and in vivo by downregulating Akt/NF-κB signaling.

Involvement of Wnt/β-catenin signaling in the mesenchymal stem cells promote metastatic growth and chemoresistance of cholangiocarcinoma

Mesenchymal stem cells (MSCs) are multi-potent progenitor cells with ability to differentiate into multiple lineages, including bone, cartilage, fat, and muscles. Recent research indicates that MSCs can be efficiently recruited to tumor sites, modulating tumor growth and metastasis. However, the underlying molecular mechanisms are not fully understood. Here, we first demonstrated that human umbilical cord-derived mesenchymal stem cells (hUC-MSCs), when mixed with human cholangiocarcinoma cell lines QBC939 in a xenograft tumor model, significantly increased the cancer cells proliferation and metastatic potency. MSCs and their conditioned media (MSC-CM) could improve the drug resistance of tumor when the compound K (CK) as an anti-cancer drug, a major intestinal bacterial metabolite of panaxoside, was administered to xenograft tumor mice. Furthermore, MSCs greatly increased the colony formation and invasion of cholangiocarcinoma cells QBC939 and Mz-ChA-1. Immunochemistry studies of cholangiocarcinoma tissue chips and transplantation tumor from nude mice showed that the expression of β-catenin was important for cholangiocarcinoma development. We further demonstrated that MSCs and MSCs-CM could promote proliferation and migration of cholangiocarcinoma cells through targeting the Wnt/β-catenin signaling pathway. hUC-MSCs or MSCs-CM stimulated Wnt activity by promoting the nuclear translocation of β-catenin, and up-regulated Wnt target genes MMPs family, cyclin D1 and c-Myc. Together, our studies highlight a critical role for MSCs on cancer metastasis and indicate MSCs promote metastatic growth and chemoresistance of cholangiocarcinoma cells via activation of Wnt/β-catenin signaling.

Umbilical cord-derived mesenchymal stem cells inhibit growth and promote apoptosis of HepG2 cells

Hepatocellular carcinoma is the fifth most common type of cancer worldwide and remains difficult to treat. The aim of this study was to investigate the effects of mesenchymal stem cells (MSCs) derived from the umbilical cord (UC‑MSCs) on HepG2 hepatocellular carcinoma cells. UC‑MSCs were co‑cultured with HepG2 cells and biomarkers of UC‑MSCs were analyzed by flow cytometry. mRNA and protein expression of genes were determined by reverse transcription‑polymerase chain reaction and flow cytometry, respectively. Passage three and seven UC‑MSCs expressed CD29, CD44, CD90 and CD105, whereas CD34 and CD45 were absent on these cells. Co‑culture with UC‑MSCs inhibited proliferation and promoted apoptosis of HepG2 cells in a time‑dependent manner. The initial seeding density of UC‑MSCs also influenced the proliferation and apoptosis of HepG2 cells, with an increased number of UC‑MSCs causing enhanced proliferation inhibition and cell apoptosis. Co‑culture with UC‑MSCs downregulated mRNA and protein expression of α‑fetoprotein (AFP), Bcl‑2 and Survivin in HepG2 cells. Thus, UC‑MSCs may inhibit growth and promote apoptosis of HepG2 cells through downregulation of AFP, Bcl‑2 and Survivin. US-MSCs may be used as a novel therapy for treating hepatocellular carcinoma in the future.

Mesenchymal stem cells enhance the metastasis of 3D-cultured hepatocellular carcinoma cells

Background

Accumulating evidences have demonstrated that mesenchymal stem cells (MSC) could be recruited to the tumor microenvironment. Umbilical cord mesenchymal stem cells (UCMSC) were attractive vehicles for delivering therapeutic agents against cancer. Nevertheless, the safety of UCMSC in the treatment of tumors including hepatocellular carcinoma (HCC) was still undetermined.

Methods

In this study, an in vitro co-culture system was established to evaluate the effect of UCMSC on the cell growth, cancer stem cell (CSC) characteristics, drug resistance, metastasis of 3D-cultured HCC cells, and the underlying mechanism was also investigated.

Results

It was found that after co-cultured with UCMSC, the metastatic ability of 3D-cultured HCC cells was significantly enhanced as indicated by up-regulation of matrix metalloproteinase (MMP), epithelial-mesenchymal transition (EMT)-related genes, and migration ability. However, cell growth, drug resistance and CSC-related gene expression of HCC cells were not affected by UCMSC. Moreover, EMT was reversed, MMP-2 expression was down-regulated, and migration ability of HCC cell was significantly inhibited when TGF-β receptor inhibitor SB431542 was added into the co-culture system.

Conclusions

Therefore, these data indicated that UCMSC could significantly enhance the tumor cell metastasis, which was due to the EMT of HCC cells induced by TGF-β.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2595-4) contains supplementary material, which is available to authorized users.

Liver epithelial cells inhibit proliferation and invasiveness of hepatoma cells

Hepatocellular carcinoma (HCC) is a worldwide malignancy with poor prognosis. Liver progenitors or stem cells could be a potential therapy for HCC treatment since they migrate toward tumors. Rat liver epithelial (RLE) cells have both progenitor and stem cell-like properties. Therefore, our study elucidated the therapeutic effect of RLE cells in rat hepatoma cells. RLE cells were isolated from 10-day old rats and characterized for stem cell marker expression. RLE cells and rat hepatoma cells (H4-IIE-C3 cells) were co-cultured and divided into four groups with different ratios of RLE and hepatoma cells. Group A had only rat hepatoma cells as a control group. The ratios of rat hepatoma and RLE cells in group B, C and D were 5:1, 1:1 and 1:5, respectively. Effective inhibition of cell proliferation and migration was found in group D when compared to group A. There was a significant decrease in Bcl2 expression and increase in late apoptosis of rat hepatoma cells when adding more RLE cells. RLE cells reduced cell proliferation and migration of rat hepatoma cells. These results suggested that RLE cells could be used as a potential cell therapy.

Mesenchymal stem cells promote tumor angiogenesis via the action of transforming growth factor β1

Mesenchymal stem cells (MSCs) may influence the growth and metastasis of various human malignancies, including hepatocellular carcinoma (HCC). Therefore, the underlying mechanisms via which MSCs are able to affect malignancies require investigation. In the present study, the potential role of MSC in the angiogenesis of HCC was investigated. A total of 17 nude mouse models exhibiting human HCC were used to evaluate the effects of MSC on angiogenesis. A total of 8 mice were injected with human MSCs via the tail vein, and the remaining 9 mice were injected with phosphate-buffered saline as a control. A total of 35 days subsequent to the injection of MSCs, the microvessel density (MVD) of tumors was evaluated by immunostaining, using cluster of differentiation 31 antibody. The mRNA levels of transforming growth factor (TGF)β1, Smad2 and Smad7 were detected using reverse transcription-quantitative polymerase chain reaction. Protein expression levels of TGFβ1 and vascular endothelial growth factor (VEGF) in tumor tissues were analyzed using ELISA. Compared with controls, MVD in MSC-treated mice was significantly increased (28.00±9.19 vs. 18.11±3.30; P=0.006). The levels of TGFβ1 mRNA in the MSC-treated group were 2.15-fold higher compared with the control group (1.27±0.61 vs. 0.59±0.39; P=0.033), and MVD was higher in the group exhibiting increased TGFβ1 mRNA levels compared with the control group (26.50±9.11 vs. 19.44±6.14; P=0.038). In addition, a close correlation between the expression levels of TGFβ1 and VEGF was identified. The results of the present study suggested that MSCs may be capable of enhancing the angiogenesis of HCC, which may be partly due to the involvement of TGFβ1.

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.

Mesenchymal stem cell-based gene therapy: A promising therapeutic strategy

Mesenchymal stem cells (MSCs) are multipotent stromal cells that exist in bone marrow, fat, and so many other tissues, and can differentiate into a variety of cell types including osteoblasts, chondrocytes, and adipocytes, as well as myocytes and neurons. Moreover, they have great capacity for self-renewal while maintaining their multipotency. Their capacity for proliferation and differentiation, in addition to their immunomodulatory activity, makes them very promising candidates for cell-based regenerative medicine. Moreover, MSCs have the ability of mobilization to the site of damage; therefore, they can automatically migrate to the site of injury via their chemokine receptors following intravenous transplantation. In this respect, they can be applied for MSC-based gene therapy. In this new therapeutic method, genes of interest are introduced into MSCs via viral and non-viral-based methods that lead to transgene expression in them. Although stem cell-based gene therapy is a relatively new strategy, it lights a new hope for the treatment of a variety of genetic disorders. In the near future, MSCs can be of use in a vast number of clinical applications, because of their uncomplicated isolation, culture, and genetic manipulation. However, full consideration is still crucial before they are utilized for clinical trials, because the number of studies that signify the advantageous effects of MSC-based gene therapy are still limited.

Culture medium of bone marrow-derived human mesenchymal stem cells effects lymphatic endothelial cells and tumor lymph vessel formation

Human bone marrow mesenchymal stem cells (hBM-MSCs) favor tumor growth and metastasis in vivo and in vitro. Neovascularization is involved in several pathological conditions, including tumor growth and metastasis. Previous studies have demonstrated that human bone marrow MSC-derived conditioned medium (hBM-MSC-CM) can promote tumor growth by inducing the expression of vascular epidermal growth factor (VEGF) in tumor cells. However, the effect of BM-MSCs on tumor lymph vessel formation has yet to be elucidated. In the present study, the effect of BM-MSCs on processes involved in lymph vessel formation, including tube formation, migration and proliferation, was investigated in human-derived lymphatic endothelial cells (HDLECs). It was identified that hBM-MSC-CM promoted the tube formation and migration of HDLECs. In addition, tumor cells were revealed to participate in lymph vessel formation. In the present study, the SGC-7901, HGC-27 and GFP-MCF-7 cell lines were treated with hBM-MSC-CM. The results demonstrated that the expression of the lymph-associated markers, prospero homeobox protein 1 and VEGF receptor-3, were increased in the SGC-7901 and HGC-27 cell lines, but not in the GFP-MCF-7 cells. The tube formation assay demonstrated that the HGC-27 cells treated with hBM-MSC-CM for 20 days underwent tube formation. These findings indicate that hBM-MSC-CM can promote tube formation in HDLECs and HGC-27 cells, which may be associated with lymph vessel formation during tumor growth and metastasis.