In JoVE (3)
- Efficient Generation of hiPSC Neural Lineage Specific Knockin Reporters Using the CRISPR/Cas9 and Cas9 Double Nickase System
- A 5-mC Dot Blot Assay Quantifying the DNA Methylation Level of Chondrocyte Dedifferentiation In Vitro
- Preparation of Authigenic Pyrite from Methane-bearing Sediments for In Situ Sulfur Isotope Analysis Using SIMS
Articles by Li Xu in JoVE
Efficient Generation of hiPSC Neural Lineage Specific Knockin Reporters Using the CRISPR/Cas9 and Cas9 Double Nickase System Shenglan Li*1,2, Haipeng Xue*1,2, Bo Long1,2,5, Li Sun1,2,6, Tai Truong1,2,4,7, Ying Liu1,2,3 1Department of Neurosurgery, The University of Texas Health Science Center at Houston, 2Center for Stem Cell and Regenerative Medicine, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, 3The Senator Lloyd & B. A. Bentsen Center for Stroke Research, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, 4Summer Research Program, Office of Educational Programs, The University of Texas Health Science Center at Houston, 5Department of Anesthesiology, Shengjing Hospital, China Medical University, 6Department of Oncology, Renji Hospital, Shanghai Jiaotong University School of Medicine, 7Biology Department, University of West Georgia Genome editing tools such as the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)/Cas (CRISPR-associated) system have greatly improved gene targeting efficiency in human induced pluripotent stem cells (hiPSCs). This manuscript describes a protocol for generating lineage specific hiPSC reporter using CRISPR/Cas system assisted homologous recombination.
A 5-mC Dot Blot Assay Quantifying the DNA Methylation Level of Chondrocyte Dedifferentiation In Vitro Zhaofeng Jia1,2, Yujie Liang3, Bin Ma4,5, Xiao Xu2,6, Jianyi Xiong2, Li Duan2, Daping Wang1,2 1Guangzhou Medical University, 2Shenzhen Key Laboratory of Tissue Engineering, Shenzhen Laboratory of Digital Orthopeadic Engineering, Department of Orthopedics, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University), 3Department of Chemistry, The Chinese University of Hong Kong, 4School of Biomedical Engineering, Shanghai Jiao Tong University, 5Renji Hospital Clinical Stem Cell Research Center, Shanghai Jiao Tong University School of Medicine, 6Shantou University Medical College We present a method to quantify DNA methylation based on the 5-methylcytosine (5-mC) dot blot. We determined the 5-mC levels during chondrocyte dedifferentiation. This simple technique could be used to quickly determine the chondrocyte phenotype in ACI treatment.
Preparation of Authigenic Pyrite from Methane-bearing Sediments for In Situ Sulfur Isotope Analysis Using SIMS Zhiyong Lin1,3, Xiaoming Sun1,2,3,4, Jörn Peckmann5, Yang Lu2,3, Harald Strauss6, Li Xu2,3, Hongfeng Lu7, Barbara M.A. Teichert6 1School of Earth Sciences and Engineering, Sun Yat-sen University, 2School of Marine Sciences, Sun Yat-sen University, 3Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, 4South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, 5Institut für Geologie, Universität Hamburg, 6Institut für Geologie und Paläontologie, Westfälische Wilhelms-Universität Münster, 7Guangzhou Marine Geological Survey Analyses of the sulfur isotopic composition (δ34S) of pyrite from methane-bearing sediments have typically focused on bulk samples. Here, we applied secondary ion mass spectroscopy to analyze the δ34S values of various pyrite generations to understand the diagenetic history of pyritization.
Other articles by Li Xu on PubMed
Effects and Mechanisms of Blocking the Hedgehog Signaling Pathway in Human Gastric Cancer Cells Oncology Letters. May, 2015 | Pubmed ID: 26137001 Excessive activation of the hedgehog (Hh) signaling pathway is important in a variety of human cancer cell types, including gastric cancer. However, the underlying mechanisms of the Hh signaling pathway in inducing gastric tumorigenesis and its downstream target genes are largely unknown. In the present study, the inhibitory effect of cyclopamine on the Hh signaling pathway was investigated in the human gastric cancer AGS cell line. It was identified that cyclopamine treatment inhibited the proliferation, migration and invasion of the AGS cells in a dose- and time-dependent manner, and resulted in the downregulation of a number of key Hh signaling pathway-associated factors [glioma-associated oncogene homolog 1, C-X-C chemokine receptor type 4 and transforming growth factor (TGF)-β1] at the RNA and protein levels. Furthermore, the secretion of TGF-β1 was significantly reduced following the administration of cyclopamine to the AGS cells. The results of the present study provided insight into the mechanisms by which the Hh signaling pathway regulates gastric cancer formation and identified the Hh signaling pathway as a potential novel therapeutic target in human gastric cancer.
Curcumin Suppresses Migration and Invasion of Human Endometrial Carcinoma Cells Oncology Letters. Sep, 2015 | Pubmed ID: 26622667 Curcumin, a widely used Chinese herbal medicine, has historically been used in anti-cancer therapies. However, the anti-metastatic effect and molecular mechanism of curcumin in endometrial carcinoma (EC) are still poorly understood. The purpose of this study was to detect the anti-metastatic effects of curcumin and the associated mechanism(s) in EC. Based on assays carried out in EC cell lines, it was observed that curcumin inhibited EC cell migration and invasion in vitro. Furthermore, following treatment with curcumin for 24 h, there was a decrease in the expression levels of matrix metalloproteinase (MMP)-2 and -9 as well as proteinase activity in EC cells. Moreover, curcumin treatment significantly decreased the levels of the phosphorylated form of extracellular signal-regulated kinase (ERK) 1/2. MEK1 overexpression partially blocked the anti-metastatic effects of curcumin. Combined treatment with ERK inhibitor U0126 and curcumin resulted in a synergistic reduction in MMP-2/-9 expression; the invasive capabilities of HEC-1B cells were also inhibited. In conclusion, curcumin inhibits tumor cell migration and invasion by reducing the expression and activity of MMP-2/9 via the suppression of the ERK signaling pathway, suggesting that curcumin is a potential therapeutic agent for EC.
Speckle-type POZ (pox Virus and Zinc Finger Protein) Protein Gene Deletion in Ovarian Cancer: Fluorescence in Situ Hybridization Analysis of a Tissue Microarray Oncology Letters. Jul, 2016 | Pubmed ID: 27347196 The aim of the present study was to investigate the status of speckle-type POZ (pox virus and zinc finger protein) protein (SPOP) gene located on chromosome 17q21 in ovarian cancer (OC). The present study evaluated a tissue microarray, which contained 90 samples of ovarian cancer and 10 samples of normal ovarian tissue, using fluorescence in situ hybridization (FISH). FISH is a method where a SPOP-specific DNA red fluorescence probe was used for the experimental group and a centromere-specific DNA green fluorescence probe for chromosome 17 was used for the control group. The present study demonstrated that a deletion of the SPOP gene was observed in 52.27% (46/88) of the ovarian cancer tissues, but was not identified in normal ovarian tissues. Simultaneously, monosomy 17 was frequently identified in the ovarian cancer tissues, but not in the normal ovarian tissues. Furthermore, the present data revealed that the ovarian cancer histological subtype and grade were significantly associated with a deletion of the SPOP gene, which was assessed by the appearance of monosomy 17 in the ovarian cancer samples; the deletion of the SPOP gene was observed in a large proportion of serous epithelial ovarian cancer (41/61; 67.21%), particularly in grade 3 (31/37; 83.78%). In conclusion, deletion of the SPOP gene on chromosome 17 in ovarian cancer samples, which results from monosomy 17, indicates that the SPOP gene may serve as a tumor suppressor gene in ovarian cancer.