Transplantation of mesenchymal stem cells (MSCs) has been used to treat a wide range of diseases, and the mechanism of action is postulated to be mediated by either differentiation into functional reparative cells that replace injured tissues or secretion of paracrine factors that promote tissue repair. To complement earlier studies that identified some of the paracrine factors, we profiled the paracrine proteome to better assess the relevance of MSC paracrine factors to the wide spectrum of MSCmediated therapeutic effects. To evaluate the therapeutic potential of the MSC paracrine proteome, a chemically defined serum-free culture medium was conditioned by MSCs derived from human embryonic stem cells using a clinically compliant protocol. The conditioned medium was analyzed by multidimensional protein identification technology and cytokine antibody array analysis and revealed the presence of 201 unique gene products. 86 -88% of these gene products had detectable transcript levels by microarray or quantitative RT-PCR assays. Computational analysis predicted that these gene products will significantly drive three major groups of biological processes: metabolism, defense response, and tissue differentiation including vascularization, hematopoiesis, and skeletal development. It also predicted that the 201 gene products activate important signaling pathways in cardiovascular biology, bone development, and hematopoiesis such as Jak-STAT, MAPK, Toll-like receptor, transforming growth factor-␤, and mTOR (mammalian target of rapamycin) signaling pathways. This study identified a large number of MSC secretory products that have the potential to act as paracrine modulators of tissue repair and replacement in diseases of the cardiovascular, hematopoietic, and skeletal tissues. Moreover our results suggest that human embryonic stem cell-derived MSC-conditioned medium has the potency to treat a variety of diseases in humans without cell transplantation.

These results suggest that decreased number and function of Treg cells might be one of mechanisms that cause immune regulation dysfunction in ITP.

Stem cell factor (SCF) plays important roles in tumor growth and angiogenesis. However, its regulatory mechanism remains largely undefined. Here, we report that hypoxia upregulated the expression of SCF in MCF-7 breast cancer cells in both messenger RNA and protein levels. When hypoxia-inducible factor (HIF)-1 alpha expression was knocked down by RNA interference, the MCF-7 cell expression of SCF was decreased significantly. Furthermore, the SCF receptor, c-kit phosphorylation was significantly strengthened by the condition culture media from hypoxic MCF-7 and MCF-7-c cells. The survival of A549 cells was more dependent on SCF under hypoxia. Analysis of SCF promoter 5'-flanking region revealed a potential hypoxia-response element (HRE; 5'-GCGTG-3') located at -68 to -64 relative to the transcriptional start site. Chromatin immunoprecipitation assay demonstrated that HIF-1 alpha directly bound to this region under normoxia, and this binding activity was significantly enhanced under hypoxia. Overexpression of HIF-1 alpha significantly upregulated the expression of luciferase reporter gene under control of the SCF promoters in both MCF-7 cells and human embryonic kidney 293 cells, but mutation of the HRE site completely blocked this effect. Epidermal growth factor was also able to enhance the SCF expression under normoxia in MCF-7 cells, which was dependent on HIF-1 alpha. Taken together, our data demonstrated that HIF-1 alpha was a key regulator of SCF expression in breast cancer cells. Hypoxia and epidermal growth factor receptor signal coexisted in the tumor microenvironment and might promote angiogenesis through HIF-1 alpha-mediated upregulation of SCF and other angiogenic factors.

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Aplastic anemia (AA) is generally considered as an immune-mediated bone marrow failure syndrome with defective hematopoietic stem cells (HSCs) and marrow microenvironment. Previous studies have demonstrated the defective HSCs and aberrant T cellular-immunity in AA using a microarray approach. However, little is known about the overall specialty of bone marrow mesenchymal stem cells (BM-MSCs). In the present study, we comprehensively compared the biological features and gene expression profile of BM-MSCs between AA patients and healthy volunteers. In comparison with healthy controls, BM-MSCs from AA patients showed aberrant morphology, decreased proliferation and clonogenic potential and increased apoptosis. BM-MSCs from AA patients were susceptible to be induced to differentiate into adipocytes but more difficult to differentiate into osteoblasts. Consistent with abnormal biological features, a large number of genes implicated in cell cycle, cell division, proliferation, chemotaxis and hematopoietic cell lineage showed markedly decreased expression in BM-MSCs from AA patients. Conversely, more related genes with apoptosis, adipogenesis and immune response showed increased expression in BM-MSCs from AA patients. The gene expression profile of BM-MSCs further confirmed the abnormal biological properties and provided significant evidence for the possible mechanism of the destruction of the bone marrow microenvironment in AA.

Circular RNAs (circRNAs) are a class of endogenous noncoding RNAs that have been demonstrated to be potential regulators in the development and progression of various types of human cancer. However, little is known about their roles in cancer initiation and progression, particular in non-small cell lung cancer (NSCLC). In the present study, the expression level of circRNA-forkhead box O3 class (FOXO3) in NSCLC specimens was determined and its functional role was investigated in NSCLC cells. By performing Taq-man based RT-qPCR, it was identified that circRNA-FOXO3 was downregulated in NSCLC tissues and cell lines. Receiver operating curve analysis indicated that circRNA-FOXO3 had a relatively higher diagnostic accuracy. The functional relevance was further examined by biological assays. circRNA-FOXO3 significantly promoted the ability of cell proliferation, migration and invasion of NSCLC cells. The linear isomer of circRNA-FOXO3, FOXO3 gene, was identified as a downstream target. RNA immunoprecipitation indicated that circRNA-FOXO3 sequestering miR-155, which further promoted linear FOXO3 expression. In addition, gain and loss functional assays indicated that circRNA-FOXO3 served an anti-oncogenic role through sequestering miR-155 and enhancing FOXO3 expression. These results suggest that circRNA-FOXO3 is a tumor-suppressor in NSCLC and may serve as a promising therapeutic target. Therefore, restoration of circRNA-FOXO3 expression could be a future approach to develop a novel treatment strategy.

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Background: CD151 is highly expressed in breast cancer cells and has been shown to accelerate breast cancer by enhancing cell growth and motility, but its regulation is poorly understood. To explore post-translation regulation of CD151, for example microRNAs, will be of great importance to claim the mechanism. Methods: A luciferase reporter assay was used to determine whether CD151 was a target of miR-124. The levels of CD151 mRNA were detected by real-time PCR and CD151 protein expression was measured by western blot and flow cytometry. The effects of miR-124 expression on growth, apoptosis, cell cycle and motility of breast cancer cells were determined. Results: We discovered that miR-124 directly targets the 3' untranslated region (3'-UTR) of CD151 mRNAs and suppresses its mRNA expression and protein translation. Both siRNA of CD151 and miR-124 mimics could significantly inhibit proliferation of breast cancer cell lines via cell cycle arrest but does not induce apoptosis. Meanwhile, miR-124 mimics significantly inhibited the motility of breast cancer cells. Conclusion: miR-124 plays a critical role in inhibiting the invasive and metastatic potential of breast cancer cells, probably by directly targeting the CD151 genes. Our findings highlight an important role of miR-124 in the regulation of invasion and metastasis by breast cancer cells and suggest a potential application for miR-124 in breast cancer treatment.