Application of cell laden hydrogels with temporally tunable stiffness in biomedical research.

Extracellular matrix (ECM) is a dynamic and complex environment regulating the cell fate and behavior. It is characterized by biophysical and biochemical properties specific for each tissue. Interestingly, hydrogels can serve as exceptional artificial cellular microenvironments as they can be designed to mimic the key features of the native ECM. They are valuable tools to understand how cells respond to complex microenvironments in normal and pathologic conditions. However, unlike the highly dynamic structure of ECM, nearly all of the conventional hydrogel platforms are primarily static and lack the dynamic properties of native extracellular matrices. Thus, it is necessary to develop dynamic hydrogels to better understand the mechanisms by which dynamic changes of ECM contribute to biological processes. Stiffness is one of the significant dynamic components of ECM which must be appropriately mimicked over time in vitro. In this review, we cover recent advances in engineering strategies to make cell laden hydrogels with temporally tunable stiffness. We also highlight the applications of these hydrogel systems in biomedicine focusing on specific examples in cancer, cardiovascular system, tissue fibrosis and stem cell research. Finally, the challenges regarding the development and application of cell laden hydrogels with temporally tunable stiffness are proposed.

Bone marrow mesenchymal stem cells improve cognitive impairments induced by methamphetamine in rats and reduce relapse.

Introduction: Chronic exposure to methamphetamine (Meth) results in permanent central nervous system damage and learning and memory dysfunction. This study aimed at investigating the therapeutic effects of bone marrow mesenchymal stem cells (BMMSCs) on cognitive impairments in Meth addicted rats and comparing intravenous (IV) delivery with intranasal (IN) delivery of BMMSCs. Methods: Adult Wistar rats were randomly divided into 6 groups; Control; Meth-addicted; IV-BMMSC (Meth administered and received IV BMMSCs); IN-BMMSC (Meth administered and received IN BMMSCs); IV-PBS (Meth administered and received IV Phosphate-buffered saline (PBS); IN-PBS (Meth administered and received IN PBS). BMMSCs were isolated, expanded in vitro, immunophenotyped, labeled, and administered to BMMSCs-treated groups (2 × 106 cells). The therapeutic effect of BMMSCs was measured using Morris water maze and Shuttle Box. Moreover, relapse-reduction was evaluated by conditioning place preference after 2 weeks following BMMSCs administration. The expression of brain-derived neurotrophic factor (BDNF) and glial-derived neurotrophic factor (GDNF) in rat hippocampus was assessed using immunohistochemistry method. Results: Administration of BMMSCs caused a significant improvement in the learning and memory functions of Meth-addicted rats and reduced the relapse (P<0.01). In behavioral tests, comparison of IV and IN BMMSC-treated groups did not show any significant difference. Administration of BMMSCs improved the protein level of BDNF and GDNF in the hippocampus, as well as causing behavioral improvement (P<0.001). Conclusion: BMMSC administration might be a helpful and feasible method to treat Meth-induced brain injuries in rats and to reduce relapse. BMMSCs were significantly higher in IV-treated group compared to the IN route. Moreover, the expression of BDNF and GDNF was higher in IN-treated rats compared with IV treated group.

Extracellular vesicles and their cells of origin: Open issues in autoimmune diseases.

The conventional therapeutic approaches to treat autoimmune diseases through suppressing the immune system, such as steroidal and non-steroidal anti-inflammatory drugs, are not adequately practical. Moreover, these regimens are associated with considerable complications. Designing tolerogenic therapeutic strategies based on stem cells, immune cells, and their extracellular vesicles (EVs) seems to open a promising path to managing autoimmune diseases' vast burden. Mesenchymal stem/stromal cells (MSCs), dendritic cells, and regulatory T cells (Tregs) are the main cell types applied to restore a tolerogenic immune status; MSCs play a more beneficial role due to their amenable properties and extensive cross-talks with different immune cells. With existing concerns about the employment of cells, new cell-free therapeutic paradigms, such as EV-based therapies, are gaining attention in this field. Additionally, EVs' unique properties have made them to be known as smart immunomodulators and are considered as a potential substitute for cell therapy. This review provides an overview of the advantages and disadvantages of cell-based and EV-based methods for treating autoimmune diseases. The study also presents an outlook on the future of EVs to be implemented in clinics for autoimmune patients.

Mesenchymal Stem/Stromal Cells Overexpressing CXCR4R334X Revealed Enhanced Migration: A Lesson Learned from the Pathogenesis of WHIM Syndrome.

C-X-C chemokine receptor type 4 (CXCR4), initially recognized as a co-receptor for HIV, contributes to several disorders, including the WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome. CXCR4 binds to its ligand SDF-1 to make an axis involved in the homing property of stem cells. This study aimed to employ WHIM syndrome pathogenesis as an inspirational approach to reinforce cell therapies. Wild type and WHIM-type variants of the CXCR4 gene were chemically synthesized and cloned in the pCDH-513B-1 lentiviral vector. Molecular cloning of the synthetic genes was confirmed by DNA sequencing, and expression of both types of CXCR4 at the protein level was confirmed by western blotting in HEK293T cells. Human adipose-derived mesenchymal stem cells (Ad-MSCs) were isolated, characterized, and subjected to lentiviral transduction with Wild type and WHIM-type variants of CXCR4. The presence of copGFP-positive MSCs confirmed the high efficiency of transduction. The migration ability of both groups of transduced cells was then assessed by transwell migration assay in the presence or absence of a CXCR4-blocking agent. Our qRT-PCR results showed overexpression of CXCR4 at mRNA level in both groups of transduced MSCs, and expression of WHIM-type CXCR4 was significantly higher than Wild type CXCR4 (P<0.05). Our results indicated that the migration of genetically modified MSCs expressing WHIM-type CXCR4 had significantly enhanced towards SDF1 in comparison with Wild type CXCR4 (P<0.05), while it was reduced after treatment with CXCR4 antagonist. These data suggest that overexpression of WHIM-type CXCR4 could lead to enhanced and sustained expression of CXCR4 on human MSCs, which would increase their homing capability; hence it might be an appropriate strategy to improve the efficiency of cell-based therapies.

Significance of epithelial-to-mesenchymal transition inducing transcription factors in predicting distance metastasis and survival in patients with colorectal cancer: A systematic review and meta-analysis.

BACKGROUND: The clinical relevance of epithelial-to-mesenchymal transition (EMT) in colorectal cancer (CRC) progression has been highlighted over the last decade. Several EMT-inducing transcription factors (EMT-TFs) have been implicated in the regulation of EMT, including Twist, Snail1, Slug, ZEB1, and ZEB2. Here, this meta-analysis aimed to predict the risk of distance metastasis and overall survival in CRC patients with high expression of EMT-TFs. MATERIALS AND METHODS: All eligible studies were searched in PubMed, Scopus, and Web of Science databases. The search was carried out to include literatures published as late as September 1, 2018. In overall, 16 studies that investigated the relationship between EMT-TFs with distance metastasis and survival in CRC patients were included. In meta-analysis, a pooled hazard ratio (HR) and odds ratio (OR) were estimated for associations. RESULTS: The results of this review indicated that expressions of all EMT-TFs are significantly correlated with poor overall survival in CRC. Moreover, there are a significant association between Twist (OR, 1.46; 95% confidence interval [CI], 1.03-2.09), Slug (OR, 3.43; 95% CI, 1.98-5.93), and ZEB2 (OR, 2.42; 95% CI, 1.09-5.40) expression with distance metastatic in CRC patients. CONCLUSION: These findings suggest that the overexpression of EMT-TFs plays a key role in increasing the risk of distance metastasis as well as decreasing overall survival in CRC patients.

The effect of different pulp-capping materials on proliferation, migration and cytokine secretion of human dental pulp stem cells.

OBJECTIVES: Biocompatibility of dental biomaterials plays a critical role in regeneration of dental stem cells. The aim of present study was to evaluate the effects of novel biomaterials of TheraCal-LC (TheraCal; Bisco), Angelus mineral trioxide aggregate (MTA; Angelus), calcium-enriched mixture (CEM; BioniqueDent), and Biodentine (Septodont) on viability of human dental pulp stem cells (hDPSCs). Moreover, the recruitment of dental pulp stem cells is a prerequisite for regeneration of damaged dentin. Therefore, in this study the effects of mentioned biomaterials on migration of hDPSCs and the secretion of some chemoattractive molecules by these cells were examined. MATERIALS AND METHODS: The cell viability of hDPSCs was assessed using MTT assay. Transwell migration assay was used to determine cell migration ability. The cytokine secretion was evaluated using enzyme-linked immunosorbent assay. RESULTS: The biomaterials of MTA, CEM, and Biodentine at different dilutions had no cytotoxic effects on hDPSCs at different time points; however, non-diluted extract of TheraCal showed toxic effects after 24, 48, and 72 hr. Meanwhile, the highest cell migration was observed in the presence of CEM and Biodentine (P<0.05). The secretion of MCP-1 and TGF-ß1 were higher in hDPSCs treated with Biodentine compared to some other groups (P<0.05, P<0.01). Moreover, TheraCal decreased protein secretion of TNF-α (P<0.05), and IL-8 (P<0.01) in hDPSCs. CONCLUSION: The biological compatibility associated with CEM and Biodentine indicates promising applications in the field of vital pulp therapy.

Sulforaphane Modulates Cell Migration and Expression of ß-Catenin and Epithelial Mesenchymal Transition Markers in Breast Cancer Cells.

BACKGROUND: We aimed to assess the effect of sulforaphane (SFN) on breast cancer cell migration and also its effect on the expression of epithelial mesenchymal transition (EMT) markers and ß-catenin. METHODS: This study was performed in Shahroud University of Medical Sciences, Shahroud, Iran from 2017-2018. In this experimental study, MDA-MB-231 cells were treated with different concentrations of SFN (5, 10, 20, 30 and 40 µM) at different time points of 24, 48, and 72 h. The control group was untreated cells. The inhibitory effects of different concentrations of SFN on cell migration at different time points were evaluated using scratch assay. Moreover, apoptosis was assessed by using flow cytometric analysis. The expression of ß-catenin and EMT markers of ZEB1, fibronectin, and claudin-1 were determined by real-time PCR. Western blotting analysis of ß-catenin was applied to determine its changes after SFN treatment. RESULTS: SFN markedly inhibited the migration of cells at concentrations of 10, 20, 30, and 40µM after 24, 48, and 72 h. At relatively, high concentrations (30, 40µM), SFN induced apoptosis. Moreover, SFN reduced the gene expression of ZEB1, fibronectin, and claudin-1 after 72 h. The expression of ß-catenin revealed a time-dependent decrease at the concentration of 40 µM SFN. CONCLUSION: Downregulation of EMT markers and ß-catenin showed accordance with the inhibition of migration. SFN could be a promising drug candidate to reduce metastasis in breast cancer.

In vitro and in vivo studies of cancer cell behavior under nutrient deprivation.

Cancer cells are confronted with nutrient deprivation because of high proliferation rate, especially at the early stage of their development. There is a frequent assumption that nutrient deprivation decreases the basal activity of cancer cells. Contrarily, there are recent evidence suggesting that cancer cells are able to modulate signaling pathways to adapt with new condition and continue their survival. This property of cancer cells is believed to be one of the prerequisites for cancer progression and chemoresistance. Moreover, recent experiments show that serum starvation in vitro as a mimic situation of nutrient deprivation in vivo triggers different signaling pathways leading to changes in cancer cell behavior, which may interfere with experimental results. Considering these facts, a better understanding of the effect of nutrient deprivation on cancer cell behavior will help us to give more accurate conclusions regarding results of in vitro studies and also to develop new strategies to treat different cancers in vivo.

Molecular targets of pomegranate (Punica granatum) in preventing cancer metastasis.

Metastasis is the primary cause of mortality and morbidity among cancer patients and accounts for about 90% of cancer deaths. The most common types of treatment for cancer metastasis are chemotherapy and radiotherapy. However, such therapy has many serious side effects that could diminish the quality of life in patients. There is increased appreciation by the scientific community that natural compounds can be potential weapons in fighting against cancer. Interestingly, much evidence shows that pomegranate (Punica granatum) has great potential to inhibit tumor growth and metastasis. In this review, we discussed the molecular targets of pomegranate, specifically, those that are prerequisite for cancer metastasis. The search was performed in Google Scholar, Medline, Scopus, and PubMed using keywords such as metastasis, pomegranate, and signaling pathways. Some of the most important papers from the search results were included. Based on recent studies, some molecules, including those involved in cell-cell and cell-extracellular matrix adhesions, are affected by pomegranate. The other targets of pomegranate are modulators of cytoskeleton dynamics and regulators of cancer cell anoikis and chemotaxis. Furthermore, the antimetastatic effect of pomegranate may be attributed to molecular changes of the extracellular matrix. Pro-inflammatory and pro-angiogenic molecules are the other targets of pomegranate regarding cancer metastasis. A wide variety of molecules can be targeted by pomegranate to suppress tumor metastasis. A better understanding of the molecules regulated by pomegranate is needed to provide a rational basis for its clinical application.

Nutrient Deprivation Modulates the Metastatic Potential of Breast Cancer Cells.

BACKGROUND: Breast cancer is the leading cause of cancer related death in women worldwide. The development of metastatic cancer is the main factor contributing to mortality. The molecular mechanisms underlying the metastatic process have yet to be clearly elucidated. However, the interplay between the tumor microenvironment and the cancer cells hold a critical role in influencing the progression of cancer metastasis. Within the microenvironment of solid tumors, the lack of sufficient vasculature leads to the development of nutrient deprived conditions. This study aimed to examine how nutrient deprivation influences factors involved in cancer progression and metastasis. Specifically, we examined how nutrient stress changes cancer cell migration, the gene expression, and cytokine production of metastasis-related factors in a human breast cancer cell line. METHODS: MCF7 breast cancer cells were cultured in serum-free media for 24, 48, and 72 h. Cell migration was evaluated using a transwell migration assay. The transcriptional expression of metastatic related genes was examined via real-time PCR. Cytokine production was examined via enzyme-linked immunosorbent assay. RESULTS: Nutrient deprivation of the MCF7 cells significantly reduced cell migration after 24 h. However, following 72 h of nutrient deprivation, there was significant increase in cell migration compared to the 24 h group. Transcriptional expression of markers involved in migration including, ß-catenin, twist, vimentin, fibronectin, ICAM1, VCAM1, and VEGF were up regulated after 72 h of nutrient deprivation. The cytokines TGFß1, IL-8, and MCP1 were differentially secreted. CONCLUSION: Nutrient deprivation is an environmental stress factor that can influence the behavior of cancer cells. Current treatments implement nutrient deprivation as a potential cancer treatment. Under short periods of nutrient deprivation, cancer cell migration is inhibited. However, our findings show that following extended lengths of nutrient deprivation, cancer cells are capable of adapting themselves to the environmental condition and restoring their migratory abilities. This, in part, may be a result of increased expression of metastasis-related genes. Further research is required to accurately identify how the expression of metastasis-related genes is modulated and controlled in response to nutrient deprivation and environmental stress.

Bone Marrow Derived Mesenchymal Stem Cells in Addiction Related Hippocampal Damages.

The brain is an important organ that controls all sensory and motor actions, memory, and emotions. Each anatomical and physiological modulation in various brain centers, results in psychological, behavioral, and sensory-motor changes. Alcohol and addictive drugs such as opioids and amphetamines have been shown to exert a great impact on brain, specifically on the hippocampus. Emerging evidence has indicated that altered hippocampal neurogenesis is associated with the pathophysiology of neuropsychological disorders including addiction. The addictive drugs impair neurogenesis and undermine the function of neural stem/progenitor cells in hippocampus. This feature was claimed to be one of the underlying mechanisms of behavioral changes in patients with addiction. As the impairment of stem cells' function has been proven to be the underlying cause of pathologic neuroadaptations in the brain, the administration of stem cell populations has shown promising results for re-modulating of neuronal status in the brain and especially in the hippocampus. Among the different types of stem cells, bone marrow derived mesenchymal stem cells are the most proper candidates for stem cell therapies. In this review article, the recent studies on the effects of addictive drugs on brain neurogenesis, and also the promising potential effects of stem cells in curing addiction related hippocampal damages are discussed.

Gene Expression Changes in Pomegranate Peel Extract-Treated Triple-Negative Breast Cancer Cells.

BACKGROUND: Triple-negative breast cancer (TNBC) is treated with highly aggressive non-targeted chemotherapies. Safer and more effective therapeutic approaches than those currently in use are needed. Natural pomegranate peel extract (PPE) has recently been found to inhibit breast cancer progression; however, its mechanisms of action remain unclear. We hypothesized that transcriptional changes in the genes encoding the adherence proteins of intercellular adhesion molecule-1 (ICAM-1) and vascular endothelial growth factor (VEGF), may explain, at least in part, the anti-metastatic properties of PPE. Recently, the tumor microenvironment has been recognized as a key contributor to cancer progression. We speculated that PPE acts by modulating matrix glycoproteins including MMP9 and fibronectin. Moreover, we hypothesized that VEGF, which is required for tumor development, may contribute to the antimetastatic effects of PPE. METHODS: To address these possibilities, MDA-MB-231 cells were treated with different doses of PPE at different time points. Apoptosis was detected by flow cytometry using annexin V and propidium iodide. Cell migration was detected with a transwell assay. Gene expression changes were analyzed by real-time PCR. RESULTS: Exposure to PPE resulted in TNBC cell death and markedly inhibited PPE-resistant cell migration. Moreover, PPE up-regulated the expression of ICAM-1, a protein essential for cell adhesion, and down-regulated the expression of MMP9, fibronectin, and VEGF, the products of which contribute to cancer cell migration. CONCLUSION: Transcriptional changes in ICAM-1, MMP9, fibronectin, and VEGF may contribute to PPE-mediated antimetastatic effects in TNBC.

Cancer metastasis versus stem cell homing: Role of platelets.

One of the major obstacles in achieving a successful stem cell therapy is insufficient homing of transplanted cells. To overcome this obstacle, understanding the underlying mechanisms of stem cell homing is of obvious importance. Central to this review is the concept that cancer metastasis can be viewed as a role model to build up a comprehensive concept of stem cell homing. In this novel perspective, the prosurvival choices of the cancerous cells in the bloodstream, their arrest, extravasation, and proliferation at the secondary site can be exploited in favor of targeted stem cell homing. To date, tumor cells have been found to employ a wide variety of strategies to promote metastasis. One of these strategies is through their ability to activate platelets and subsequently activated platelets serve cancer cell survival and metastasis. Accordingly, in the first part of this review the roles of platelets in cancer metastasis as well as stem cell homing are discussed. Next, we provide some lessons learned from cancer metastasis in favor of developing strategies for improvement of stem cell homing with emphasis on the role of platelets. Based on direct or indirect evidence from metastasis, strategies such as manipulation of stem cells to enhance interaction with platelets, preconditioning-pretreatment of stem cells with platelets in vitro, and coinjection of both stem cells and platelets are proposed to improve stem cell homing.

Pomegranate peel extract inhibits expression of ß-catenin, epithelial mesenchymal transition, and metastasis in triple negative breast cancer cells.

The standard treatment for triple-negative breast cancer (TNBC) is chemotherapy, which is highly toxic to patients; thereby, there is a need to identify safer and more effective therapeutic approaches. Medicinal plants constitute a common alternative for cancer treatment. Pomegranate is a well-known fruit in this context, but its antimetastatic property has not been extensively studied. As breast cancer-related deaths from TNBC are mainly due to metastasis, the present study was designed to investigate the antimigratory effect of pomegranate peel extract (PPE) on TNBC cells. For this purpose, the MDA-MB-231 cells were treated with different concentrations of PPE for 24, 48 and 72 hr. The effects of PPE on cell migration and invasion were determined by wound healing and transwell assays. To address the possible molecular mechanisms underlying the antimetastatic effect of PPE, real-time quantitative PCR analysis of selected epithelial mesenchymal transition (EMT) markers were performed. Moreover, the expression of ß-catenin as a critical factor in promoting cancer metastasis was examined. PPE markedly inhibited the migration and invasion of cells at concentrations of 25, 50, 100, 250, 500, and 1000µg/ml. At relatively high concentrations (500, 1000µg/ml), PPE induced apoptosis. Moreover, PPE decreased the gene expression of vimentin, ZEB1, and ß-catenin and also increased the expression of E-cadherin in TNBC cells. The protein level of ß-catenin, as measured using western analysis, revealed a time-dependent decrease at the concentration of 1000µg/ml PPE. Downregulation of EMT markers and ß-catenin showed accordance with the inhibition of migration and invasion. The present data show that PPE could be a promising drug candidate to reduce metastasis in TNBC cells.

Augmented migration of mesenchymal stem cells correlates with the subsidiary CXCR4 variant.

Use of mesenchymal stem cells (MSCs) has been introduced as a promising tool, for structural and functional recovery of damaged tissues/organs. Studies have indicated that interactions between chemokine receptors and their ligands have a critical role in homing of MSCs to the site of injury. Although CXCR4 variants have been characterized, the exact role of each transcript in homing has remained unclear. In this study, cells were pretreated with various hypoxia-mimicking compounds (valproic acid, cobalt-chloride, and deferoxamine mesylate). Results indicated that both variants of CXCR4 were overexpressed after 24 hours of treatments and their expression could cooperatively induce and promote the cell migration. Moreover, deferoxamine mesylate was more effective in overexpression of variant A (lo), which resulted in higher level of CXCR4 protein and the highest rate of migration of the cells. In conclusion, our findings may have important potential implications in clinical applications, reinforcing the concept that manipulating the expression of specific CXCR4 variants may increase migration of MSCs.

Effects of Two Calcium Silicate Cements on Transforming Growth Factor-ß1 Secretion from Human Dental Pulp Stem Cells.

Introduction: The aims of this in vitro study were to evaluate the effects of two calcium silicate based cements, Calcum-enriched Mixture (CEM) and Biodentine on proliferation of human dental pulp stem cells (hDPSCs) and the effects of proposed cements on the secretion of Transforming Growth Factor ß1 (TGF-ß1). Methods and materials: The cell cultures of human Dental Pulp Stem Cells (hDPSCs) at passage 3-5 were treated with various dilutions (1/1, 1/2, 1/4, 1/8, 1/16, and 1/32) of CEM and Biodentine extracts to assess the cell proliferation using 3-(4, 5-dimethylthiazol-2-Y1)-2, 5-diphenyltetrazolium brovide (MTT) assay after 48 and 72 h. The amount of TGF-ß 1 secretion were estimated after 72 h using an enzyme-linked immunosorbent assay. Data were analyzed using the one-way analysis of variance (ANOVA) followed by the Dunnett's test at the level of significance set at 0.05. Result: CEM showed the highest rates of cell proliferation compared to Biodentine after 72 h (P<0.05). A greater amount of TGF-ß1 was secreted by hDPSCs treated with Biodentine compared to CEM (P<0.05). These differences were statistically significant (P<0.05). Conclusion: In this in vitro study hDPSCs showed more proliferation capacity with CEM rather than Biodentine and TGF-ß1 secretion rate in Biodentine was higher.

CXCR4 and CCR7: Two eligible targets in targeted cancer therapy.

Cancer is one of the most common cause of death in the world with high negative emotional, economic, and social impacts. Conventional therapeutic methods, including chemotherapy and radiotherapy, have not proven satisfactory and relapse is common in most cases. Recent studies have focused on targeted therapy with more precise identification and targeted attacks to the cancer cells. For this purpose, chemokine receptors are proper targets and among them, CXCR4 and CCR7, with a crucial role in cancer metastasis, are being considered as desired candidates for investigation. In this review paper, the most important experimental results are highlighted on the potential targeted therapies based on CXCR4 and CCR7 chemokine receptors.

Berberine suppresses migration of MCF-7 breast cancer cells through down-regulation of chemokine receptors.

OBJECTIVES: Berberine is one of the main alkaloids and it has been proven to have different pharmacological effects including inhibition of cell cycle and progression of apoptosis in various cancerous cells; however, its effects on cancer metastasis are not well known. Cancer cells obtain the ability to change their chemokine system and convert into metastatic cells. In this study, we examined the effect of berberine on breast cancer cell migration and its probable interaction with the chemokine system in cancer cells. MATERIALS AND METHODS: The MCF-7 breast cancer cell line was cultured, and then, treated with berberine (10, 20, 40 and 80 µg/ml) for 24 hr. MTT assay was used in order to determine the cytotoxic effect of berberine on MCF-7 breast cancer cells. Wound healing assay was applied to determine the inhibitory effect of berberine on cell migration. Moreover, real-time quantitative PCR analysis of selected chemokine receptors was performed to determine the probable molecular mechanism underlying the effect of berberine on breast cancer cell migration. RESULTS: The results of wound healing assay revealed that berberine decreases cell migration. Moreover, we found that the mRNA levels of some chemokine receptors were reduced after berberine treatment, and this may be the underlying mechanism for decreased cell migration. CONCLUSION: Our results indicate that berberine might be a potential preventive biofactor for human breast cancer metastasis by targeting chemokine receptor genes.

Chemically primed bone-marrow derived mesenchymal stem cells show enhanced expression of chemokine receptors contributed to their migration capability.

OBJECTIVES: The limited homing potential of bone-marrow-derived mesenchymal stem cells (BM-MSC) is the key obstacle in MSC-based therapy. It is believed that chemokines and chemokine receptor interactions play key roles in cellular processes associated with migration. Meanwhile, MSCs express a low level of distinct chemokine receptors and they even lose these receptors on their surface after a few passages which influence their therapeutic applications negatively. This study investigated whether treatment of BM-MSCs with hypoxia-mimicking agents would increase expression of some chemokine receptors and cell migration. MATERIALS AND METHODS: BM-MSCs were treated at passage 2 for our gene expression profiling. All qPCR experiments were performed by SYBR Green method in CFX-96 Bio-Rad Real-Time PCR. The Boyden chamber assay was utilized to investigate BM-MSC homing. RESULTS: Possible approaches to increasing the expression level of chemokine receptors by different hypoxia-mimicking agents such as valproic acid (VPA), CoCl2, and desferrioxamine (DFX) are described. Results show DFX efficiently up-regulate the CXCR7 and CXCR4 gene expression while VPA increase only the CXCR7 gene expression and no significant change in expression level of CXCR4 and the CXCR7 gene was detectable by CoCl2 treatment. Chemotaxis assay results show that pre-treatment with DFX, VPA, and Cocl2 enhances significantly the migration ability of BM-MSCs compared with the untreated control group and DFX treatment accelerates MSCs homing significantly with a higher rate than VPA and Cocl2 treatments. CONCLUSION: Our data supports the notion that pretreatment of MSC with VPA and DFX improves the efficiency of MSC therapy by triggering homing regulatory signaling pathways.

Injectable hydrogel delivery plus preconditioning of mesenchymal stem cells: exploitation of SDF-1/CXCR4 axis toward enhancing the efficacy of stem cells' homing.

Clinical applications of mesenchymal stem cells (MSCs) rely on their capacity to home and engraft in the appropriate target injury tissues for the long term. However, their homing efficiency has been observed to be very poor because of the lack or modifications of homing factors SDF-1α and CXCR4 receptors. Hence, this study was designed to investigate the homing and retention of pretreated human adipose tissue-derived MSCs (hASCs) from three different delivery routes in response to SDF-1α, released from chitosan-based injectable hydrogels. After stimulation of ASCs with a hypoxia mimicking agent, the expression level and functionality of CXCR4 were analyzed by flowcytometric analysis (FACS), transwell migration assay and qPCR. Then, the homing/retention of pretreated DiI-labeled hASCs were compared through three different in vivo delivery routes, 2 weeks after transplantation in Wistar rats. The cells were tracked histologically by fluorescent microscope and by PCR for human-specific CXCR4 gene. Results showed CXCR4 has dynamic expression pattern and pretreatment of hASCs significantly up-regulates CXCR4, leading to an increase in migration capacity toward 100 ng/mL SDF-1α in vitro and homing into the subcutaneously implanted hydrogel releasing SDF-1α in vivo. Furthermore, it seems that SDF-1α is particularly important in the retention of ASCs, in addition to its chemoattraction role. In summary, the delivery route in which the ASCs were mixed with the hydrogel rather than systemic delivery and local injection and preconditioning undertaken to increase CXCR4 expression concomitant with SDF-1α delivery by the injectable hydrogel, allowed for further homing/retention of ASCs. This might be a promising way to get better therapeutic outcomes in stem cell therapy.