Isolation and Localization of Mesenchymal Stem Cells in Human Palatine Tonsil by W5C5 (SUSD2).

BACKGROUND/AIMS: Although tonsil-mesenchymal stem cells (T-MSCs) have been studied as a new autologous or homologous source of MSCs, research on specific markers of MSCs and localization for purified T-MSC isolation has not yet been reported. This study investigates the expression of W5C5 (SUSD2) in tonsil stromal cells and the colony-forming ability and differentiation potential of W5C5+ cells to determine the usefulness of W5C5+ MSCs as a marker that can be used for the purification of T-MSCs. In addition, the location of W5C5+ cells expressed in the tonsil tissues is examined. METHODS: T-MSCs were isolated from the tonsillar tissues of 12 patients undergoing tonsillectomy. The colony-forming ability, surface markers, proliferation potential, and differentiation capacities of purified W5C5+ MSCs, W5C5- MSCs, and unselected T-MSCs were evaluated. The location of the W5C5+ cells in the tonsillar tissues was also investigated by immunohistochemistry. RESULTS: W5C5 was expressed in 2.5±0.4% of fresh human tonsil stromal cells. W5C5+ cells formed many colonies, but W5C5- cells did not form any colonies. The colony-forming number of W5C5+ cells (74.4 ± 9.8) was significantly higher than that of unselected tonsil stromal cells (23.6 ± 3.7). However, the differences in proliferation potential, surface marker expression, and differentiation potential between W5C5+ T-MSCs and unselected T-MSCs were not significant. W5C5+ cells were identified in the perivascular area around the blood vessels. CONCLUSION: W5C5+ T-MSCs possessed typical MSC properties with high colony-forming efficiency, and niches of W5C5+ T-MSCs were located in the perivascular area of tonsil tissues. These findings suggest that W5C5 is a useful single marker for the isolation of purified T-MSCs.

Effects of donor age, long-term passage culture, and cryopreservation on tonsil-derived mesenchymal stem cells.

OBJECTIVES: Human mesenchymal stem cells (MSCs) are efficacious in various cellular therapeutic applications and have been isolated from several tissues. Recent studies have reported that human tonsil tissue contains a new source of progenitor cells, potentially applicable for cell-based therapies. Information about the effects of donor age, long-term passage and cryopreservation are essential for clinical applications and cell-based therapies. Therefore, the authors investigated how the morphology, cell-surface markers, proliferation potential and differentiation capacity of tonsil-derived MSCs (T-MSCs) were affected by donor age, long-term passage, and cryopreservation. MATERIALS AND METHODS: T-MSCs were isolated from tonsillar tissue of 20 patients undergoing tonsillectomy. Authors evaluated the effects of donor-age, long-term passage, and cryopreservation on the morphology, surface markers, proliferation potential and differentiation capacities of T-MSCs. RESULTS: T-MSCs exhibited a fibroblast-like, spindle-shaped appearance. There were no significant morphological differences according to donor age, long-term passage or cryopreservation. T-MSCs isolated from donors of various ages were positive for markers CD90, CD44, and CD73, but negative for CD45, CD31, and HLA-DR. There were no significant differences in the expression of positive and negative surface markers as a function of donor age, long-term passage and cryopreservation. T-MSCs from different donor age groups showed similar proliferation potentials after passage 2. After long-term passage and cryopreservation, there were no significant morphological differences. Cryopreservation did not affect the proliferation potential of T-MSCs, but there was a significant decrease in the proliferation potential in long-term passage T-MSCs (passage 15). The effect of donor age, long-term passage and cryopreservation on the in vitro adipogenic, osteogenic, and chondrogenic differentiation potential of T-MSCs was not significant. CONCLUSION: The effect of donor age, long-term passage culture, and cryopreservation on T-MSC properties are negligible, except for the proliferation capacity of long-term cultured T-MSCs. Therefore, T-MSCs are considered to be promising MSCs that can be used as future alternative sources for autologous or allogenic MSCs.

The Role of Magnesium Ion Substituted Biphasic Calcium Phosphate Spherical Micro-Scaffolds in Osteogenic Differentiation of Human Adipose Tissue-Derived Mesenchymal Stem Cells.

This study was investigated the role of magnesium (Mg2+) ion substituted biphasic calcium phosphate (Mg-BCP) spherical micro-scaffolds in osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs). Mg-BCP micro-scaffolds with spherical morphology were successfully prepared using in situ co-precipitation and spray drying atomization process. The in vitro cell proliferation and differentiation of hAT-MSCs were determined up to day 14. After in vitro biological tests, Mg-BCP micro-scaffolds with hAT-MSCs showed more enhanced osteogenicity than pure hAT-MSCs as control group by unique biodegradation of TCP phase and influence of substituted Mg2+ ion in biphasic nanostructure. Therefore, these results suggest that Mg-BCP micro-scaffolds promote osteogenic differentiation of hAT-MSCs.

miR-137 controls proliferation and differentiation of human adipose tissue stromal cells.

BACKGROUND/AIMS: Demonstrating the molecular mechanisms of human adipose tissue-derived mesenchymal stem cells (hADSCs) differentiation and proliferation could develop hADSCs-based cell therapy. METHODS: The microRNA-137 (miR-137) and cell division control protein 42 homolog (CDC42) levels were regulated by oligonucleotides transfection. The adipogenic differentiation was induced for 10 days in an adipogenic medium and assessed by using an Oil Red O stain. The regulation of miR-137 on CDC42 expression was determined by western blot, real-time PCR and luciferase reporter assay. RESULTS: We confirmed the roles of miR-137 on hADSCs proliferation and adipogenic differentiation. We showed that overexpression of miR-137 inhibited both hADSCs proliferation and adipogenic differentiation. Overexpression of miR-137 also downregulated protein and mRNA levels of CDC42, a predicted target of miR-137. In contrast, inhibition of miR-137 with 2'-O-methyl antisense RNA increased proliferation and adipogenic differentiation in hADSCs. Luciferase reporter activity in the miR-137 target site within the CDC42 3'UTR was lower in miR-137-transfected hADSCs than in control miRNA-transfected hADSCs. RNA interference-mediated downregulation of CDC42 in hADSCs inhibited their proliferation and adipogenic differentiation. CONCLUSION: Our results indicate that miR-137 regulates hADSCs adipogenic differentiation and proliferation by directly targeting CDC42. These findings improve our knowledge of the molecular mechanisms governing hADSCs differentiation and proliferation.

BMP2 increases adipogenic differentiation in the presence of dexamethasone, which is inhibited by the treatment of TNF-α in human adipose tissue-derived stromal cells.

BACKGROUND/AIMS: The aim of this study was to analyze the effect of BMP2 on osteogenic differentiation of human adipose tissue-derived stromal cells (hADSCs). METHODS: Cultured cells were differentiated into osteogenic lineage in the presence of BMP2. Gene expressions were determined by real time PCR. RESULTS: BMP2 increased (2/8) or inhibited (6/8) osteogenic differentiation according to hADSCs batches. Regardless of the BMP2 action on osteogenic differentiation, BMP2 induced lipid droplet formation under an osteogenic differentiation condition in all batches of hADSCs, not hBMSCs, to be tested, which was confirmed by analysis of adipogenesis related genes expression. hADSCs expressed various BMP receptors. BMP2 increased expression of BMP2-responsive genes such as DLX3 and ID2, and induced SMAD1 phosphorylation in hADSCs and hBMSCs. BMP2 increased osteogenic differentiation of hADSCs in osteogenic medium in which dexamethasone was omitted. The addition of BMP2 in the control culture media containing dexamethasone alone lead to formation of lipid droplets and increased C/EBP-α expression in hADSCs. In the presence of TNF-α, BMP2 stimulated osteogenic differentiation of hADSCs even in hADSCs batches in which treatment of BMP2 alone inhibited osteogenic differentiation. CONCLUSION: These data indicate that the control of osteogenesis and adipogenesis in hADSCs is closely related, and that hADSCs have preferential commitment to adipogenic lineages.

Effect of phorbol 12-myristate 13-acetate on the differentiation of adipose-derived stromal cells from different subcutaneous adipose tissue depots.

Human adipose-tissue-derived stromal cells (hADSCs) are abundant in adipose tissue and can differentiate into multi-lineage cell types, including adipocytes, osteoblasts, and chondrocytes. In order to define the optimal harvest site of adipose tissue harvest site, we solated hADSCs from different subcutaneous sites (upper abdomen, lower abdomen, and thigh) and compared their proliferation and potential to differentiate into adipocytes and osteoblasts. In addition, this study examined the effect of phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, on proliferation and differentiation of hADSCs to adipocytes or osteoblasts. hADSCs isolated from different subcutaneous depots have a similar growth rate. Fluorescence-activated cell sorting (FACS) analysis showed that the expression levels of CD73 and CD90 were similar between hADSCs from abdomen and thigh regions. However, the expression of CD105 was lower in hADSCs from the thigh than in those from the abdomen. Although the adipogenic differentiation potential of hADSCs from both tissue regions was similar, the osteogenic differentiation potential of hADSCs from the thigh was greater than that of hADSCs from the abdomen. Phorbol 12-myristate 13-acetate (PMA) treatment increased osteogenic differentiation and suppressed adipogenic differentiation of all hADSCs without affecting their growth rate and the treatment of Go6983, a general inhibitor of protein kinase C (PKC) blocked the PMA effect. These findings indicate that the thigh region might be a suitable source of hADSCs for bone regeneration and that the PKC signaling pathway may be involved in the adipogenic and osteogenic differentiation of hADSCs.

MicroRNA 21 regulates the proliferation of human adipose tissue-derived mesenchymal stem cells and high-fat diet-induced obesity alters microRNA 21 expression in white adipose tissues.

A better understanding of the molecular mechanisms that govern human adipose tissue-derived mesenchymal stem cells (hASCs) differentiation could provide new insights into a number of diseases including obesity. Our previous study demonstrated that microRNA-21 (miR-21) controls the adipogenic differentiation of hASCs. In this study, we determined the expression of miR-21 in white adipose tissues in a high-fat diet (HFD)-induced obesity mouse model to examine the relationship between miR-21 and obesity and the effect of miR-21 on hASCs proliferation. Our study showed biphasic changes of miR-21 expression and a correlation between miR-21 level and adipocyte number in the epididymal fat of HFD mice. Over-expression of miR-21 decreased cell proliferation, whereas inhibiting miR-21 with 2'-O-methyl-antisense RNA increased it. Over-expression of miR-21 decreased both protein and mRNA levels of STAT3, whereas inhibiting miR-21 with 2'-O-methyl-antisense RNA increased these levels. The activity of a luciferase construct containing the miR-21 target site from the STAT3 3'UTR was lower in LV-miR21-infected hASCs than in LV-miLacZ infected cells. RNA interference-mediated down-regulation of STAT3 decreased cell proliferation without affecting adipogenic differentiation. These findings provide the evidence of the correlation between miR-21 level and adipocyte number in the white adipose tissue of HFD-induced obese mice, which provides new insights into the mechanisms of obesity.

Role of IRAK1 on TNF-induced proliferation and NF-ĸB activation in human bone marrow mesenchymal stem cells.

In this study, we determined the effect of TNF-α on hBMSCs proliferation as well as the role of IL-1 receptor-associated kinase 1 (IRAK1) on TNF-α signaling. Western blot analysis revealed that TNF-α treatment increased the phosphorylation of IRAK1 in hBMSCs. The downregulation of IRAK1 inhibited TNF-α-induced NF-ĸB activation and COX-2 expression. TNF-α treatment increased hBMSCs proliferation in a dose-dependent manner and increased ERK, JNK, and NF-ĸB activity. U0126, an ERK inhibitor, decreased hBMSCs proliferation and significantly blocked TNF-α -induced hBMSCs proliferation. In cells with IRAK1 or TRADD downregulation, the U0126 treatment inhibited hBMSCs proliferation and significantly suppressed TNF-α-induced hBMSCs proliferation. The downregulation of IRAK1 or TRADD inhibited TNF-α-induced ERK and JNK activation, and hBMSCs proliferation. Inhibition of NF-ĸB by decoy oligonucleotides reduced the TNF-α-induced hBMSCs proliferation. Immunoprecipitation analysis showed that IRAK1 does not physically interact with TNF receptor 1 (TNFR1) even in the presence of TNF-α. Suppression of IRAK1 binding protein (IRAK1BP1) inhibited TNF-α-induced increase of the proliferation and ERK1 phosphorylation of hBMSCs in the presence of TNF-α. Our data indicate that TNF-α modulates hBMSCs proliferation through ERK signaling pathways, and that IRAK1 plays an important role in TNF-α-induced NF-ĸB activation in hBMSCs.

miR-21 modulates tumor outgrowth induced by human adipose tissue-derived mesenchymal stem cells in vivo.

Mesenchymal stem cells (MSCs) have generated a great deal of interest in clinical situations, due principally to their potential use in regenerative medicine and tissue engineering applications. However, the therapeutic application of MSCs remains limited, unless the favorable effects of MSCs on tumor growth in vivo, and the long-term safety of the clinical applications of MSCs, can be more thoroughly understood. In this study, we determined whether microRNAs can modulate MSC-induced tumor outgrowth in BALB/c nude mice. Overexpression of miR-21 in human adipose-derived stem cells (hADSCs) inhibited hADSC-induced tumor growth, and inhibition of miR-21 increased it. Downregulation of transforming growth factor beta receptor II (TGFBR2), but not of signal transducer and activator of transcription 3, in hADSCs showed effects similar to those of miR-21 overexpression. Downregulation of TGFBR2 and overexpression of miR21 decreased tumor vascularity. Inhibition of miR-21 and the addition of TGF-ß increased the levels of vascular endothelial growth factor and interleukin-6 in hADSCs. Transplantation of miR-21 inhibitor-transfected hADSCs increased blood flow recovery in a hind limb ischemia model of nude mice, compared with transplantation of control oligo-transfected cells. These findings indicate that MSCs might favor tumor growth in vivo. Thus, it is necessary to study the long-term safety of this technique before MSCs can be used as therapeutic tools in regenerative medicine and tissue engineering.

MRI of the proximal femur predicts marrow cellularity and the number of mesenchymal stem cells.

PURPOSE: To determine whether the marrow conversion index (MCI) in MRI is related to the total number of mononuclear and mesenchymal stem cells (MSCs) in proximal femoral metaphysis of patients with hip osteoarthritis. MATERIALS AND METHODS: Thirty-two hips of 32 consecutive patients who underwent total hip arthroplasty (THA) for hip osteoarthritis were included in this study. MRI of the hip was performed preoperatively and MCI was subsequently calculated. Three-milliliter bone marrow samples were obtained from the proximal femur during THA and the number of total mononuclear cells was determined using a hemocytometer. Colony forming unit-fibroblasts (CFU-Fs) assays of MSCs were performed by transferring a total of 2 × 10(4) mononuclear cells to each of five 60-mm plates. One week later, the numbers of colonies were counted. RESULTS: The total number of mononuclear cells decreased with increasing MCI. Likewise, the prevalence and total number of CFU-Fs increased with increasing number of total mononuclear cells, and decreased with increasing MCI. CONCLUSION: Our results suggest that measurement of MCI in MRI can be an objective and noninvasive method to predict marrow cellularity and the number of MSCs in patients with hip osteoarthritis.

Safety and effect of adipose tissue-derived stem cell implantation in patients with critical limb ischemia: a pilot study.

BACKGROUND: Treatment of critical limb ischemia (CLI) by bypass operation or percutaneous vascular intervention is occasionally difficult. The safety and efficacy of multiple intramuscular adipose tissue-derived mesenchymal stem cells (ATMSC) injections in CLI patients was determined in the study. METHODS AND RESULTS: The study included 15 male CLI patients with ischemic resting pain in 1 limb with/without non-healing ulcers and necrotic foot. ATMSC were isolated from adipose tissue of thromboangiitis obliterans (TAO) patients (B-ATMSC), diabetes patients (D-ATMSC), and healthy donors (control ATMSC). In a colony-forming unit assay, the stromal vascular fraction of TAO and diabetic patients yielded lesser colonies than that of healthy donors. D-ATMSC showed lower proliferation abilitythan B-ATMSC and control ATMSC, but they showed similar angiogenic factor expression with control ATMSC and B-ATMSC. Multiple intramuscular ATMSC injections cause no complications during the follow-up period (mean follow-up time: 6 months). Clinical improvement occurred in 66.7% of patients. Five patients required minor amputation during follow-up, and all amputation sites healed completely. At 6 months, significant improvement was noted on pain rating scales and in claudication walking distance. Digital subtraction angiography before and 6 months after ATMSC implantation showed formation of numerous vascular collateral networks across affected arteries. CONCLUSIONS: Multiple intramuscular ATMSC injections might be a safe alternative to achieve therapeutic angiogenesis in patients with CLI who are refractory to other treatment modalities.

Dynamic Capabilities and an ESG Strategy for Sustainable Management Performance.

This research explores the dynamic capabilities required for firms to implement environmental, social, and governance (ESG) strategies, and investigates sustainable management performance that can be created based on them. By using dynamic capabilities theory, we integrate sustainable management and the ESG literature to suggest a research model and identify the factors that act as the catalysts achieving sustainability. The data used for the analysis were collected from 78 firms listed on the Korea Exchange (KRX) with assets totaling more than 2 trillion Korean won. In this study, the partial least squares structural equation model (PLS-SEM) is applied. We found that absorptive capability and adaptive capability significantly affect sustainable management performance through implementation of the ESG strategy as a mediating variable. In particular, a firm's implementation of an ESG strategy is a significant determinant that impacts sustainable management performance. We also believe our model contributes to the current knowledge by filling several research gaps, and our findings offer valuable and practical implications not only for achieving sustainable growth but also for creation of competitive advantage.

Effect of the modulation of leucine zipper tumor suppressor 2 expression on proliferation of various cancer cells functions as a tumor suppressor.

ß-catenin is a component of the adhesion complex linking cadherin and actin cytoskeleton, as well as a major mediator of the Wnt pathway, which is a critical signal cascade regulating embryonic development, cell polarity, carcinogenesis, and stem cell function. NF-κB functions as a key regulator of immune responses and apoptosis, and mutations in NF-κB signaling can lead to immune diseases and cancers. We previously showed that NF-κB-mediated modulation of ß-catenin/Tcf signaling is mediated by leucine zipper tumor suppressor 2 (Lzts2) and that lzts2 expression is differentially regulated in various cancer cells. Its functional significances, however, are poorly understood. We showed that NF-κB-induced modulation of ß-catenin/Tcf pathway is regulated by lzts2 expression in mesenchymal stem cells (MSCs) and several cancer cells, and that NF-κB-induced lzts2 expression is differentially regulated among cancer cell types. Here, using a promoter-reporter assay and EMSA, we demonstrate that NF-κB regulates lzts2 transcription by directly binding to the lzts2 promoter, and that NF-κB-induced lzts2 transcription differs by cell types. Modulation of lzts2 expression by lentiviral techniques affected proliferation and tumorigenicity of several cancer cell lines such as breast, colon, prostate cancer, and glioma, but did not affect cisplatin sensitivity or cell migration. Our data indicate that lzts2 expression is transcriptionally regulated by NF-κB activities, and the modulation of lzts2 expression affects cell proliferation and tumor growth through the Wnt/ß-catenin pathway in various cancer cell lines.

NF-kappaB activation stimulates osteogenic differentiation of mesenchymal stem cells derived from human adipose tissue by increasing TAZ expression.

Tumor necrosis factor-alpha (TNF-alpha) is a skeletal catabolic agent that stimulates osteoclastogenesis and inhibits osteoblast function. Although TNF-alpha inhibits the mineralization of osteoblasts, the effect of TNF-alpha on mesenchymal stem cells (MSC) is not clear. In this study, we determined the effect of TNF-alpha on osteogenic differentiation of stromal cells derived from human adipose tissue (hADSC) and the role of NF-kappaB activation on TNF-alpha activity. TNF-alpha treatment dose-dependently increased osteogenic differentiation over the first 3 days of treatment. TNF-alpha activated ERK and increased NF-kappaB promoter activity. PDTC, an NF-kappaB inhibitor, blocked the osteogenic differentiation induced by TNF-alpha and TLR-ligands, but U102, an ERK inhibitor, did not. Overexpression of miR-146a induced the inhibition of IRAK1 expression and inhibited basal and TNF-alpha- and TLR ligand-induced osteogenic differentiation. TNF-alpha and TLR ligands increased the expression of transcriptional coactivator with PDZ-binding motif (TAZ), which was inhibited by the addition of PDTC. A ChIP assay showed that p65 was bound to the TAZ promoter. TNF-alpha also increased osteogenic differentiation of human gastroepiploic artery smooth muscle cells. Our data indicate that TNF-alpha enhances osteogenic differentiation of hADSC via the activation of NF-kappaB and a subsequent increase of TAZ expression.

MiR-21 regulates adipogenic differentiation through the modulation of TGF-beta signaling in mesenchymal stem cells derived from human adipose tissue.

A better understanding of the molecular mechanisms that govern human adipose tissue-derived mesenchymal stem cells (hASCs) differentiation could improve hASCs-based cell therapy and provide new insights into a number of diseases, including obesity. In this study, we examined the roles of microRNA-21 (miR-21) in adipogenic differentiation of hASCs. We found that miR-21 expression was transiently increased after induction of adipogenic differentiation, peaked at 3 days, and returned to the baseline level 8 days. Lentiviral overexpression of miR-21 enhanced adipogenic differentiation. Overexpression of miR-21 decreased both protein and mRNA levels of TGFBR2. The expression of TGFBR2 was decreased during adipogenic differentiation of hASCs in concordance with an increase in the level of miR-21. In contrast, inhibiting miR-21 with 2'-O-methyl-antisense microRNA increased TGFBR2 protein levels in hASCs, accompanied by decreased adipogenic differentiation. The activity of a luciferase construct containing the miR-21 target site from the TGFBR2 3'UTR was lower in LV-miR21-infected hASCs than in LV-miLacZ infected cells. TGF-beta-induced inhibition of adipogenic differentiation was significantly decreased in miR-21 overexpressing cells compared with control lentivirus-transduced cells. RNA interference-mediated downregulation of SMAD3, but not of SMAD2, increased adipogenic differentiation. Overexpression and inhibition of miR-21 altered SMAD3 phosphorylation without affecting total levels of SMAD3 protein. Our data are the first to demonstrate that the role of miR-21 in the adipogenic differentiation of hASCs is mediated through the modulation of TGF-beta signaling. This study improves our knowledge of the molecular mechanisms governing hASCs differentiation, which may underlie the development of obesity or other metabolic diseases.

IFATS collection: Immunomodulatory effects of adipose tissue-derived stem cells in an allergic rhinitis mouse model.

Adipose tissue-derived stem cells (ASCs) exhibit immunosuppressive effects in allogeneic transplantation. However, there is no report that evaluates the in vivo immune-modulating effect of ASCs in an experimental allergic rhinitis (AR) model. We investigated whether ASCs migrate to the nasal mucosa in an AR mouse model and evaluated the immune-modulating effect of ASCs in the AR mouse model. Cultured ASCs (2 x 10(6)) were injected i.v. before the first allergen challenge in the AR mouse model. Migration of ASCs to the nasal mucosa was evaluated by immunofluorescence. The immunomodulatory effects of ASCs were evaluated by nasal symptoms, histology, serum ovalbumin (OVA)-specific antibody, and the cytokine profile of the spleen. ASCs migrated to the nasal mucosa in the AR mouse model. ASCs significantly reduced allergic symptoms and inhibited eosinophilic inflammation in the nasal mucosa. ASCs significantly decreased the serum allergen-specific IgE level and the IgG(1)/IgG(2a) ratio and significantly increased the IgG(2a) level in the AR mouse model. ASCs inhibited interleukin (IL)-4 and IL-5 production from OVA-incubated splenocytes, but enhanced interferon-gamma production. In conclusion, ASCs can migrate to the nasal mucosa in the AR mouse model and inhibit eosinophilic inflammation partly via shifting to a T-helper 1 (Th1) from a Th2 immune response to allergens.

The role of chemokines in proangiogenic action induced by human adipose tissue-derived mesenchymal stem cells in the murine model of hindlimb ischemia.

The proangiogenic action of human adipose tissue-derived mesenchymal stem cells (hASCs) transplantation has been shown to be mediated by secretory factors. In this study, we determined if human granulocyte chemotactic protein-2(GCP2) or monocyte chemoattractant protein-1(MCP1) is involved in the proangiogenic action of hASCs transplantation in the hindlimb ischemia model. hASCs secrete GCP2 and MCP1, which leads to increased tubule formation. The downregulation of GCP2 or MCP1 decreased MCP1 and GCP2 secretion, respectively, whereas the external addition of GCP2 or MCP1 increased MCP1 and GCP2, respectively. Additionally, the treatment of GCP2 and MCP1 increased VEGF secretion, while the downregulation of GCP2 and MCP1 showed the opposite effect on VEGF secretion. Downregulation of GCP2 and MCP1 expression also inhibited hASCs-induced proangiogenic action, while the overexpression of GCP2 increased it. Finally, the downregulation of MCP1 or VEGF inhibited the GCP2 overexpression-induced increase in blood flow recovery. Taken together, these data indicate that the proangiogenic action of hASCs transplantation is mediated by the interaction between GCP2, MCP1 and VEGF, which are secreted from the transplanted cells.

Cancer-derived lysophosphatidic acid stimulates differentiation of human mesenchymal stem cells to myofibroblast-like cells.

Lysophosphatidic acid (LPA) is enriched in ascites of ovarian cancer patients and is involved in growth and invasion of ovarian cancer cells. Accumulating evidence suggests cancer-associated myofibroblasts play a pivotal role in tumorigenesis through secreting stromal cell-derived factor-1 (SDF-1). In the present study, we demonstrate that LPA induces expression of alpha-smooth muscle actin (alpha-SMA), a marker for myofibroblasts, in human adipose tissue-derived mesenchymal stem cells (hADSCs). The LPA-induced expression of alpha-SMA was completely abrogated by pretreatment of the cells with Ki16425, an antagonist of LPA receptors, or by silencing LPA(1) or LPA(2) isoform expression with small interference RNA (siRNA). LPA elicited phosphorylation of Smad2/3, and siRNA-mediated depletion of endogenous Smad2/3 or adenoviral expression of Smad7, an inhibitory Smad, abrogated the LPA induced expression of alpha-SMA and phosphorylation of Smad2/3. LPA-induced secretion of transforming growth factor (TGF)-beta1 in hADSCs, and pretreatment of the cells with SB431542, a TGF-beta type I receptor kinase inhibitor, or anti-TGF-beta1 neutralizing antibody inhibited the LPA-induced expression of alpha-SMA and phosphorylation of Smad2. Furthermore, ascites from ovarian cancer patients or conditioned medium from ovarian cancer cells induced expression of alpha-SMA and phosphorylation of Smad2, and pretreatment of the cells with Ki16425 or SB431542 abrogated the expression of alpha-SMA and phosphorylation of Smad2. In addition, LPA increased the expression of SDF-1 in hADSCs, and pretreatment of the cells with Ki16425 or SB431562 attenuated the LPA-stimulated expression of SDF-1. These results suggest that cancer-derived LPA stimulates differentiation of hADSCs to myofibroblast-like cells and increases SDF-1 expression through activating autocrine TGF-beta1-Smad signaling pathway.

Differential effect of NF-kappaB activity on beta-catenin/Tcf pathway in various cancer cells.

beta-Catenin/Tcf and NF-kappaB pathways play an important role in biological functions. We determined the underlying mechanisms of differential interaction between two pathways in various human cancer cell lines. NF-kappaB positively regulated beta-catenin/Tcf pathways in human glioblastoma, whereas it has an opposite effect on beta-catenin/Tcf pathways in colon, liver, and breast cancer cells. Expression of lucine zipper tumor suppressor 2 (lzts2) was positively regulated by NF-kappaB activity in colon, liver, and breast cancer cells, whereas negatively regulated in glioma cells. Downregulation of lzts2 increased the beta-catenin/Tcf promoter activity and inhibited NF-kappaB-induced modulation of the nuclear translocation of beta-catenin. These data indicate that the differential crosstalk between beta-catenin/Tcf and NF-kappaB pathway in various cancer cells is resulted from the differences in the regulation of NF-kappaB-induced lzts2 expression.

Mesenchymal stem cells derived from human adipose tissues favor tumor cell growth in vivo.

Mesenchymal stem cells (MSCs) have generated a great deal of interest in clinical situations, due principally to their potential use in regenerative medicine and tissue engineering applications. However, the therapeutic application of MSCs remains limited, unless the favorable effects of MSCs for tumor growth in vivo and the long-term safety of the clinical applications of MSCs can be understood more thoroughly. In this study, MSCs derived from human adipose tissues (hASCs) together with tumor cells were transplanted subcutaneously or intracranially into BALB/c nude mice to observe tumor outgrowth. The results indicated that hASCs with H460 or U87MG cells promoted tumor growth in nude mice. Our histopathological analyses indicated that the co-injection of tumor cells with hASCs exerted no influence on the formation of intratumoral vessels. Co-culture of tumor cells with hASCs or the addition of conditioned medium (CM) from hASCs effected an increase in the proliferation of H460 or U87MG cells. Co-injection of hASCs with tumor cells effected an increase in tumor cell viability in vivo, and also induced a reduction in apoptotic cell death. CM from hASCs inhibited hydrogen peroxide-induced cell death in H460 or U87MG cells. These findings indicated that MSCs could favor tumor growth in vivo. Thus, it is necessary to conduct a study concerning the long-term safety of this technique before MSCs can be used as therapeutic tools in regenerative medicine and tissue engineering.