[Show abstract][Hide abstract] ABSTRACT: Bone marrow-derived mesenchymal stem cells (BMSCs, also known as bone marrow-derived mesenchymal stromal cells) are known to be a component of the tumor microenvironment. BMSCs are multipotent stromal cells that can differentiate into a variety of cell types, including osteocytes, chondrocytes, adipocytes, epithelial cells and endothelial cells. Stem cells found in niches or transplanted into injured tissues constantly encounter hypoxic stress. Areas with very low to no oxygen pressure exist in solid tumors. The differentiation capacity of BMSCs under hypoxic conditions remains controversial.
In this study, a hypoxic workstation, set at an oxygen concentration of 0.2% was used to mimic the hypoxic microenvironment of cancer in vivo. Oil red O staining and alkaline phosphatase staining were used to examine the adipogenic or osteogenic differentiation, respectively, of BMSCs. Real-time PCR was performed to explore the expression of adipocyte- or osteocyte-specific genes. An RT2 Profiler(TM) PCR Array was used to screen a panel of 84 genes associated with human adipogenesis in BMSCs under normal and hypoxic conditions. A dual-luciferase reporter assay and chromatin immunoprecipitation (ChIP) were applied to analyze promoter activity to evaluate the possible regulatory mechanism of adipocyte-specific gene expression.
We found that this extreme hypoxia impaired osteogenic differentiation as indicated by the attenuation of alkaline phosphatase (ALP) activity and the reduced expression of osteogenic markers osteocalcin and osteopontin. Moreover, extreme hypoxia enhanced adipogenic differentiation, as indicated by the accumulation of lipid droplets and the expression of the adipocyte-specific genes leptin, LPL, CFD, PGAR and HIG2. In the extreme hypoxic conditions (0.2% oxygen), the overexpression of CCAAT enhancer-binding proteins (C/EBPs), especially C/EBPδ, and HIF-1A upregulated the promoter activities of adipocyte-specific genes such as leptin, CFD, HIG2, LPL, PGAR. In the present study, peroxisome proliferator-activated receptor-gamma (PPARγ) exerted a negative effect on the differentiation of BMSCs into adipocytes.
In view of these findings, extreme hypoxia induced the adipogenic differentiation of BMSCs through HIF-1A and C/EBPs. These findings might provide clues regarding the roles of BMSCs in the cancer microenvironment.
[Show abstract][Hide abstract] ABSTRACT: A porous β-tricalcium phosphate (β-TCP) bioceramic scaffold was successfully prepared with our homemade selective laser sintering system. Microstructure observation by a scanning electron microscope showed that the grains grew from 0.21 to 1.32 μm with the decrease of laser scanning speed from 250 to 50 mm min−1. The mechanical properties increased mainly due to the improved apparent density when the laser scanning speed decreased to 150 mm min−1. When the scanning speed was further decreased, the grain size became larger and the mechanical properties severely decreased. The highest Vickers hardness and fracture toughness of the scaffold were 3.59 GPa and 1.16 MPa m1/2, respectively, when laser power was 11 W, spot size was 1 mm in diameter, layer thickness was 0.1–0.2 mm and laser scanning speed was 150 mm min−1. The biocompatibility of these scaffolds was assessed in vitro with MG63 osteoblast-like cells and human bone marrow mesenchymal stem cells. The results showed that all the prepared scaffolds are suitable for cell attachment and differentiation. Moreover, the smaller the grain size, the better the cell biocompatibility. The porous scaffold with a grain size of 0.71 μm was immersed in a simulated body fluid for different days to assess the bioactivity. The surface of the scaffold was covered by a bone-like apatite layer, which indicated that the β-TCP scaffold possesses good bioactivity. These discoveries demonstrated the evolution rule between grain microstructure and the properties that give a useful reference for the fabrication of β-TCP bone scaffolds.
Science and Technology of Advanced Materials 09/2013; 14(5):055002. DOI:10.1088/1468-6996/14/5/055002 · 3.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Mesenchymal stem cells (MSCs) are emerging as promising gene vectors for cancer therapy because of their unique characteristics, including the ease of their expansion and genetic modification and their remarkable tumor-tropic properties. However, there remains a concern that MSCs may promote cancer progression. Surprisingly, there are conflicting reports within the literature describing both the promotion and inhibition of cancer progression by MSCs. The reasons for this discrepancy are still unknown. The surface markers, differentiation ability, and tumorigenic roles of MSCs, as well as their effect on immunoregulation, produce heterogeneity. In this review, we describe the heterogeneity of MSCs by the species from which they are derived, the methodology for their isolation and the context of their interactions with cancer cells. The conflicting roles of MSCs in tumor progression may be attributable to the bimodal effect of unmodified MSCs on immunoregulation. MSCs have been reported to suppress T-cell function and inhibit graft-versus-host disease (GVHD). On the other hand, MSCs elicit the graft-versus-tumor (GVT) effect in some cases. Selective allodepletion may be used to dissociate GVHD from the GVT effect. Understanding the conditions that balance GVHD and the GVT effect of MSCs may be crucial to advance cancer therapy research with respect to MSCs.
[Show abstract][Hide abstract] ABSTRACT: Dysregulation of microRNA (miRNA) biogenesis is implicated in cancer development and progression. Dicer and Drosha are established regulators of miRNA biogenesis. In this study, we used a miRNA array to evaluate the microRNA expression profiles in nasopharyngeal carcinoma (NPC) samples. The significance analysis of microarrays (SAM) showed a global down-regulation of miRNA expression in NPC samples compared to normal nasopharyngeal epithelial tissues. Notably, miR-18a, a member of the oncogenic miR-17-92 cluster, was up-regulated in the NPC samples and ell lines. Clinical parameter studies showed that higher levels of miR-18a correlated with NPC advanced stage, lymph node metastasis, EBV infection and a higher death rate from NPC, indicating an oncogenic roles in NPC development. The expression levels of miR-18a and Dicer1 were inversely related in NPC tissues. Further studies demonstrated that miR-18a negatively regulated Dicer1 by binding to the 3'UTR of Dicer1. In vitro and in vivo biological function assays showed that miR-18a promoted the growth, migration and invasion of NPC cells by regulating Dicer1 expression, which caused the global down-regulation of miRNA expression levels including miR-200 family and miR-143. Furthermore, we found that the epithelial mesenchymal transition (EMT) marker E-Cadherin and the oncogene K-Ras were aberrantly expressed after miR-18a transduction, and these alterations were directly induced by down-regulation of the miR-200 family and miR-143. Collectively, our findings indicate that miR-18a plays an oncogenic role in the development of NPC by widespread down-regulation of the miRNome and could be a potential therapeutic target for NPC.
[Show abstract][Hide abstract] ABSTRACT: An association between carcinogenesis and inflammation has long been appreciated. Chemically induced colitis-associated cancer (CAC) is a classical mouse model for investigating 'inflammation-cancer link' in the intestine. Diverse mechanisms behind this non-resolving inflammation model have been reported before, most of them were emphasized on key cancer genes, cytokines, and signal transduction abnormality based on prior knowledge. In this study, we dynamically and globally dissect the alteration of key pathways in the development from colitis to colorectal cancer. Striking evidence from gene expression profiling, serum cytokines detection, and immunohistochemistry analysis all reveals that different key pathways [NF-κB, STAT3, p38 mitogen-activated protein kinase (MAPK), and Wnt/β-catenin signaling] and their target genes are hyperactive in different phases of the inflammation-cancer link. Nuclear factor-κB (NF-κB) and STAT3 signaling are hyperactive in the whole process, while p38 MAPK and Wnt/β-catenin signaling are only hyperactive in the beginning and ending, respectively. Through this unbiased system biological approach, we provide strong evidence that different key pathways are specifically involved in different phases, which bridge the gap between inflammation and cancer.
[Show abstract][Hide abstract] ABSTRACT: CD164 (Endolyn) is a sialomucin, which has been found to play roles in regulating proliferation, adhesion, and differentiation of hematopoietic stem cells. Possible association of CD164 with solid cancer development remains unknown.
We first studied CD164 expression in biopsies from colorectal cancer, breast, and ovary cancer patients by semi-quantitative immunohistochemistry, and found that CD164 was strongly expressed in all the colorectal cancer samples compared to the matching normal colon tissues. The possible roles of CD164 in colon cancer development were further investigated using a well-established human colon cancer cell line HCT116. We found that knockdown of CD164 expression in HCT116 cells significantly inhibited cell proliferation, mobility, and metastasis in vitro and in vivo. The knockdown of CD164 expression was associated with decreased chemokine receptor CXCR4 expression HCT116 cell surface and immunoprecipitation studies showed that CD164 formed complexes with CXCR4.
CD164 is highly expressed in the colon cancer sites, and it promotes HCT116 colon cancer cell proliferation and metastasis both in vitro and in vivo, and the effects may act through regulating CXCR4 signaling pathway. Therefore, CD164 may be a new target for diagnosis and treatment for colon cancer.
Cancer Investigation 03/2012; 30(5):380-9. DOI:10.3109/07357907.2012.666692 · 2.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: MicroRNAs (miRNAs) are small non-coding RNAs that participate in the spatiotemporal regulation of messenger RNA (mRNA) and protein synthesis. Recent studies have shown that some miRNAs are involved in the progression of nasopharyngeal carcinoma (NPC). However, the aberrant miRNAs implicated in different clinical stages of NPC remain unknown and their functions have not been systematically studied.
In this study, miRNA microarray assay was performed on biopsies from different clinical stages of NPC. TargetScan was used to predict the target genes of the miRNAs. The target gene list was narrowed down by searching the data from the UniGene database to identify the nasopharyngeal-specific genes. The data reduction strategy was used to overlay with nasopharyngeal-specifically expressed miRNA target genes and complementary DNA (cDNA) expression data. The selected target genes were analyzed in the Gene Ontology (GO) biological process and Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathway. The microRNA-Gene-Network was build based on the interactions of miRNAs and target genes. miRNA promoters were analyzed for the transcription factor (TF) binding sites. UCSC Genome database was used to construct the TF-miRNAs interaction networks.
Forty-eight miRNAs with significant change were obtained by Multi-Class Dif. The most enriched GO terms in the predicted target genes of miRNA were cell proliferation, cell migration and cell matrix adhesion. KEGG analysis showed that target genes were significantly involved in adherens junction, cell adhesion molecules, p53 signalling pathway et al. Comprehensive analysis of the coordinate expression of miRNAs and mRNAs reveals that miR-29a/c, miR-34b, miR-34c-3p, miR-34c-5p, miR-429, miR-203, miR-222, miR-1/206, miR-141, miR-18a/b, miR-544, miR-205 and miR-149 may play important roles on the development of NPC. We proposed an integrative strategy for identifying the miRNA-mRNA regulatory modules and TF-miRNA regulatory networks. TF including ETS2, MYB, Sp1, KLF6, NFE2, PCBP1 and TMEM54 exert regulatory functions on the miRNA expression.
This study provides perspective on the microRNA expression during the development of NPC. It revealed the global trends in miRNA interactome in NPC. It concluded that miRNAs might play important regulatory roles through the target genes and transcription factors in the stepwise development of NPC.
BMC Medical Genomics 01/2012; 5(1):3. DOI:10.1186/1755-8794-5-3 · 2.87 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Mesenchymal stem cells (MSCs) that are present in many adult tissues can generate new cells either continuously or in response to injury/cancer. An increasing number of studies demonstrated that MSCs have the ability to differentiate into cells of mesodermal origin and transdifferentiate into cells such as hepatocytes, neural cells. There has been growing interest in the application of MSCs to cancer therapy. The relationship between MSCs and cancer cells remains highly controversial. In this study, we analyzed the interaction of bone marrow-derived MSCs and cancer cells by cell-cell contact and transwell culture system. The flow cytometry and real-time polymerase chain reaction showed that after coculture of MSCs and cancer cells, MSCs displayed the hematopoietic cell markers such as CD34, CD45, and CD11b. The CD68, MRCI, and CSF1R were dramatically upregulated after coculture. The cytokine array showed that MSCs after coculture secreted monokines and chemokines much more than that of intact MSCs. The MSCs under tumor conditions were responsive to stimulation with lipopolysaccharide by cytokines release. The tumor-conditioned MSCs showed phagocytic ability and enhanced release of nitric oxide, which are the characteristics of macrophages. Calcium ion is an important intracellular messenger responsible for differentiation and gene expression regulations. The influx of Ca(2+) into MSCs was obviously reduced after coculture. The blocking of calcium channel with verapamil obviously increased the expression of CD34, CD45, and CD11b, thus indicating that the diminished calcium ion influx is coupled with the hematopoietic differentiation of MSCs under tumor conditions. Taken together, in a cancer environment, MSCs could effectively differentiate into immune hematopoietic cells, precisely macrophages. Diminished transient influx of Ca(2+) may mediate the hematopoietic differentiation of MSCs.
Stem cells and development 09/2011; 21(9):1418-28. DOI:10.1089/scd.2011.0319 · 3.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the function and mechanism of miR-149 in nasopharyngeal carcinoma (NPC).
The expression of miR-149 was examined by real-time PCR and calculated by 2(-▵▵Ct) method. The cell proliferation was analyzed by MTT assay. The cell migration and invasion were shown by the wound healing assay and transwell migration assay, and the expression of E-cadherin was detected by Western blot.
The expression of miR-149 was higher in NPC cell lines 5-8F and 6-10B than that in normal immortalized nasopharyngeal epithelial NP69. MTT assay showed that miR-149 promoted the proliferation of NPC cell lines. The wound healing assay showed miR-149 promoted the mobility and invasion of NPC cell lines. Inhibition of miR-149 reduced the ability of NPC cell lines to proliferate and invade. miR-149 downregulated the expression of E-cadherin, whereas antagomir which mediated knockdown of miR-149 significantly upregulated the expression of E-cadherin.
miR-149 might be involved in the invasion and metastasis of NPC through regulation of epithelial-mesenchymal transition (EMT).
Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences 07/2011; 36(7):604-9. DOI:10.3969/j.issn.1672-7347.2011.07.004