Project description:Metastasis is a major factor for mortality in patients with hepatocellular carcinoma (HCC). Thus, there is a need for predictive biomarker(s) for detecting the tipping point before metastasis, so as to prevent further deterioration. To discover early warning signals of pulmonary metastasis in HCC, we analysed time-series gene expression data in the spontaneous pulmonary metastasis mouse HCCLM3-RFP model with our novel dynamic network biomarker (DNB) method. To simulate tumour growth and metastasis in patient livers, we used the spontaneous pulmonary metastasis mouse model, HCCLM3-RFP, which involves the orthotopic transplanted human HCCLM3 cell line labelled with a stable fluorescent protein.We observed that, hepatic tumours in orthotopic xenograft HCCLM3-RFP mice grew gradually from the second to the fifth week after orthotopic implantation in the primary liver tissue, whereas spontaneous pulmonary metastasis occurredonly at the last time point (the fifth week after orthotopic implantation).Thus, we chose the second, third, fourth, and fifth weeks after orthotopic implantation as observation points to collect liver tumours of five orthotopic xenograft mice at each time point and to assess the whole-genome expression.
Project description:Pulmonary metastasis is the main cause of medical failure and death of osteosarcoma patients. Our recent study identified IRX1 as a potential metastasis-driving gene in osteosarcoma. Studies showed that IRX1 can promote the migration, invasion and anoikis resistance of osteosarcoma cells. We generated 143B stable IRX1 knockdown and control cell lines, and found that IRX1 knockdown can inhibit the pulmonary metastasis of 143B cells in orthotopic mouse osteosarcoma model. Expression microarrays are performed in143B-shCtrl and 143B-shIRX1 cells to study the mechanism of IRX1 on promoting metastasis of osteosarcoma
Project description:Gene expression profiling has been widely used to screen for metastasis-associated genes by comparing the difference in paired primary and metastatic colorectal carcinomas, orthotopic implantation mouse model or cells with different metastatic potential in the field of CRC research In our study, we observed that the genes differentially expressed in M5 relative to its parent SW480 cell line Here we used the SW480, a human CRC cell line, as a model system. In vivo variant lines with increasing metastatic capacity were selected in a metastatic orthotopic model of human CRC. A subpopulation named as M5 with enhanced metastatic abilities to liver was isolated by in vivo selection of SW480 cells. We identified genes associated with tumor metastasis by comparing the difference between high metastatic subclone and its parent cells.
Project description:Pulmonary metastasis is the main cause of medical failure and death of osteosarcoma patients. Our recent study identified IRX1 as a potential metastasis-driving gene in osteosarcoma. Studies showed that IRX1 can promote the migration, invasion and anoikis resistance of osteosarcoma cells. We generated 143B stable IRX1 knockdown and control cell lines, and found that IRX1 knockdown can inhibit the pulmonary metastasis of 143B cells in orthotopic mouse osteosarcoma model.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.