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ABSTRACT: Xenotransplantation of human cells into immunodeficiency mice has been frequently used to study stem cells in tissue repair and regeneration and cancer cell metastasis. However, a sensitive and reproducible method to quantify cell engraftment lacks. Here, we developed a Real-Time PCR-based method which facilitated consistent detection and quantification of small amounts of human cells distributed in mouse organs after infusion. The principle of the method was to directly detect a humans-specific sequence in the human-murine genomic DNA mixture. In a mouse myocardial infarction model, the Real-Time PCR-based method consistently determined the amounts of human mesenchymal stem cells (hMSCs) engrafted into the heart and other organs 7 days after infusion of as little as 2.5 × 10(5) cells, indicating a high sensitivity, and the amounts of hMSCs detected in mice highly correlated to the numbers of hMSCs transplanted. Importantly, different from previous PCR-based methods, our method produced highly consistent and reproducible results. The reliability of the method was further proven by parallel analyses of DiI-labeled hMSCs in tissue sections and in single cell suspensions of mice. Our data show that the present human genomic DNA-specific primers-based Real-Time PCR method is sensitive and highly reproducible in determining the amount of xenotransplanted human cells in murine tissues.
Stem cell reviews 09/2012; · 5.08 Impact Factor
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ABSTRACT: Pokemon is an oncogenic transcription factor involved in cell growth, differentiation and oncogenesis, but little is known about its role in human breast cancer. In this study, we aimed to reveal the role of Pokemon in breast cancer progression and patient survival and to understand its underlying mechanisms.
Tissue microarray analysis of breast cancer tissues from patients with complete clinicopathological data and more than 20 years of follow-up were used to evaluate Pokemon expression and its correlation with the progression and prognosis of the disease. DNA microarray analysis of MCF-7 cells that overexpress Pokemon was used to identify Pokemon target genes. Chromatin immunoprecipitation (ChIP) and site-directed mutagenesis were utilized to determine how Pokemon regulates survivin expression, a target gene.
Pokemon was found to be overexpressed in 158 (86.8%) of 182 breast cancer tissues, and its expression was correlated with tumor size (P = 0.0148) and lymph node metastasis (P = 0.0014). Pokemon expression led to worse overall (n = 175, P = 0.01) and disease-related (n = 79, P = 0.0134) patient survival. DNA microarray analyses revealed that in MCF-7 breast cancer cells, Pokemon regulates the expression of at least 121 genes involved in several signaling and metabolic pathways, including anti-apoptotic survivin. In clinical specimens, Pokemon and survivin expression were highly correlated (n = 49, r = 0.6799, P < 0.0001). ChIP and site-directed mutagenesis indicated that Pokemon induces survivin expression by binding to the GT boxes in its promoter.
Pokemon promotes breast cancer progression by upregulating survivin expression and thus may be a potential target for the treatment of this malignancy.
Breast cancer research: BCR 03/2011; 13(2):R26. · 5.24 Impact Factor
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ABSTRACT: Mesenchymal stem cells (MSCs) hold great promise for the treatment of difficult diseases. As MSCs represent a rare cell population, ex vivo expansion of MSCs is indispensable to obtain sufficient amounts of cells for therapies and tissue engineering. However, spontaneous differentiation and aging of MSCs occur during expansion and the molecular mechanisms involved have been poorly understood.
Human MSCs in early and late passages were examined for their expression of genes involved in osteogenesis to determine their spontaneous differentiation towards osteoblasts in vitro, and of genes involved in self-renewal and proliferation for multipotent differentiation potential. In parallel, promoter DNA methylation and hostone H3 acetylation levels were determined. We found that MSCs underwent aging and spontaneous osteogenic differentiation upon regular culture expansion, with progressive downregulation of TERT and upregulation of osteogenic genes such as Runx2 and ALP. Meanwhile, the expression of genes associated with stem cell self-renewal such as Oct4 and Sox2 declined markedly. Notably, the altered expression of these genes were closely associated with epigenetic dysregulation of histone H3 acetylation in K9 and K14, but not with methylation of CpG islands in the promoter regions of most of these genes. bFGF promoted MSC proliferation and suppressed its spontaneous osteogenic differentiation, with corresponding changes in histone H3 acetylation in TERT, Oct4, Sox2, Runx2 and ALP genes.
Our results indicate that histone H3 acetylation, which can be modulated by extrinsic signals, plays a key role in regulating MSC aging and differentiation.
PLoS ONE 01/2011; 6(6):e20526. · 4.09 Impact Factor
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ABSTRACT: Natural flavonoids have broad biological activity, including anticancer. In this study, a series of novel flavone derivatives were synthesized with the substitutions of chlorine, isopropyl, methoxy, and nitro groups on the benzene ring of flavone skeleton to develop effective anticancer agents. Antiproliferative assays showed that the synthesized chemicals possess notable activity against hepatocarcinoma cells (HepG-2); in particular, the compound 6f with chlorine and dimethoxy modifications at the two benzene rings showed an IC(50) at 1.1 microM to HepG-2. The 6f also displayed marked anticancer activity towards a panel of cancer cells, including nasopharyngeal carcinoma cells (CNE-2 and CNE-1), breast adenocarcinoma cell (MCF-7), and epithelial carcinoma cells (Hela). Exposing HepG-2 cells to compound 6f at 10 microM induced chromatin condensation, nuclear disassembly, and DNA fragmentation. In 6f-treated HepG-2 cells, the sub-G(0) population was remarkably increased; and in these cells, both caspase-8 and caspase-9 activity was significantly increased, which in turn activated caspase-3. In addition, proapoptotic Bax was upregulated by compound 6f while the antiapoptotic Bcl-2 was downregulated. Taken together, our data suggest that the new flavonoid derivative 6f triggers apoptosis through both death-receptor and mitochondria-dependent intrinsic pathways, being a potent therapeutic agent against hepatocarcinoma.
Bioorganic & medicinal chemistry 09/2010; 18(17):6322-8. · 2.82 Impact Factor
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ABSTRACT: Breast carcinoma is the most common malignancy in women. The progression of tumor is associated with overexpression of inhibitors of apoptosis proteins (IAPs) such as survivin and multidrug resistant P-glycoprotein (P-gp). PI3K/Akt pathway is involved in cell cycle progression, apoptosis and neoplastic transformation. PI3K/Akt has been shown to regulate survivin in breast cancer. The aim of this study was to investigate the expression of survivin and P-gp, the modulation of survivin by P-gp in PI3K/Akt during the progression of drug resistance (MDR) in MCF-7 breast cancer cells and adriamycin (ADR)-resistant MCF-7/ADR cells. The expression of survivin and P-gp in MCF-7/ADR cells were higher than that of the MCF-7 cells using RT-PCR and Western blot analysis. Survivin transcription was associated with P-glycoprotein/MDR1 overexpression using promoter activity analysis. LY294002, specific inhibitor of PI3K could suppress survivin and P-gp expression, decreased survivin promoter activity and enhanced cell sensitivity to drugs. This study shows survivin transcription was associated with P-glycoprotein/MDR1 overexpression, PI3k/Akt pathway was involved in P-glycoprotein/MDR1 associated survivin transcription activity in the multidrug resistant MCF-7 breast cancer cells.
Oncology Reports 05/2010; 23(5):1469-75. · 1.84 Impact Factor
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ABSTRACT: P-glycoprotein (Pgp), encoded by the multidrug resistance 1 (MDR1) gene, is an efflux transporter and plays an important role in pharmacokinetics. In this study, we demonstrated that the pokemon promoter activity, the pokemon mRNA and protein expression can be significantly inhibited by Pgp. Chromatin immunoprecipitation assay showed that Pgp can bind the pokemon prompter to repress pokemon transcription activity. Furthermore, Pgp regulated pokemon transcription activity through expression of p53 as seen by use of p53 siRNA transfected MCF-7 cells or p53 mutated MDA-MB-231 cells. Moreover, p53 was detected to bind with Pgp in vivo using immunoprecipitation assay. Taken together, we conclude that Pgp can regulate the expression of pokemon through the presence of p53, suggesting that Pgp is a potent regulator and may offer an effective novel target for cancer therapy.
International Journal of Molecular Sciences 01/2010; 11(9):3309-051. · 2.60 Impact Factor
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ABSTRACT: Zbtb7A is a proto-oncogenic transcriptional regulator that plays an important role in adipogenesis, osteogenesis and oncogenesis, but little is known about the regulation of Zbtb7A gene expression which is of importance in the function uncovering of this gene.
Here, a 5'-flanking region of the human Zbtb7A gene was cloned and characterized. It was found that the GC box within Zbtb7A promoter is necessary for the promoter activity. Furthermore, we identified that Sp1 acts as an activator in the regulation of Zbtb7A promoter activity and the physical interaction between Sp1 and GC box is responsible for the activation of Zbtb7A gene promoter.
Our results confirmed that Sp1 upregulates Zbtb7A gene expression via direct binding to GC box within the promoter.
BMC Research Notes 10/2009; 2:175.
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ABSTRACT: Pituitary tumor-transforming gene 1 (PTTG1), a proto-oncogene, is associated with tumor formation, proliferation and invasiveness. F-PBF(beta-TrCP), a fusion protein, was produced by replacing the WD40-repeat of F-box protein beta-TrCP with the PTTG1-binding factor (PBF) for targeted degradation of PTTG1. To evaluate the function of F-PBF(beta-TrCP), PTTG1-EGFP fusion protein was constructed. Our results showed that F-PBF(beta-TrCP) can both degrade exogenous PTTG1-EGFP fusion protein in COS-7 cells and endogenous PTTG1 protein in HeLa cells and the targeted PTTG1 knock down resulted in bFGF mRNA level down-regulation and inhibition of proliferation and clonogenicity in HeLa cells. In conclusion, targeted degradation of PTTG1 by F-PBF(beta-TrCP) has antitumor activity in vitro in HeLa cells. These results suggest that F-PBF(beta-TrCP) could be used for cancer treatment by targeted degradation of PTTG1.
Journal of Biotechnology 11/2008; 139(1):6-11. · 3.05 Impact Factor
