Pivotal role of microRNA-9 in osteosarcoma tumorigenesis and tumor progression

MicroRNA-9 (miR-9) has a well-established role in various tumors; the clinical significance and potential mechanism of miR-9 in human osteosarcoma (OS) has not been elucidated. The aim of this study was to investigate the mechanism and role of miR-9 expression in osteosarcoma cells. miR-9 expression in the OS cell line MG-63 and OS tissues was compared to that in a human osteoblastic cell line (hFOB 1.19) and adjacent normal tissues, respectively, by reverse transcriptase-polymerase chain reaction. miR-9 expression was downregulated by introducing small interfering RNA against miR-9 (si-miR-9) into the cells, and the proliferative, migratory, and invasive capacities of si-miR-9-transfected MG-63 cells were compared to those of control MG-63 cells. miR-9 was significantly upregulated in OS tissues and cell lines compared to the corresponding non-cancerous bone tissues (P < 0.05) and human osteoblastic cell line (P < 0.05), respectively. Upregulated miR-9 expression was also associated with increased cell proliferation (P < 0.05), migration (P < 0.05), and invasion (P < 0.05), and decreased apoptotic ability (P < 0.05). These results suggest that miR-9 may play a pivotal role in tumorigenesis and tumor progression in osteosarcoma.

Parallel proteomic analysis in muscle-invasive bladder transitional cell carcinoma and cancer-related stroma

To bring about improvements in cancer biology research and elucidate mechanism-based therapeutic targets, we studied the proteome expression profile of purified normal urothelial cells (cancer cells) and normal stromal cells (cancerous stromal cells). Based on the expression profile, biomarker discovery and the mechanisms of multi-step carcinogenesis were explored. We found that 1412/1403 unique proteins commonly appeared in 4 sets of paired cancer/normal tissue, and 1753 proteins were differentially expressed. Three hundred and forty-one proteins were repeatedly expressed in both cancer and cancer stromal cells; 358 proteins were repeatedly expressed in both normal urothelial and normal stromal cells. Among them, 186/203 proteins were specific repeat expressions in cancer/normal tissue and thought to play an important role in cancer-stroma interactions. Differential proteins were further analyzed using bioinformatic tools and compared with the published literature. GO enrichment/depletion analysis indicated that carcinogenesis involved all the biological processes and all the cellular components. Five hundred and sixty-eight differential proteins were located in the well-known biological Kyoto Encyclopedia of Genes and Genomes pathways, including metabolic pathways, ribosome spliceosome, and endocytosis. One hundred and thirty-nine of the 186 proteins that displayed specific repeat expressions in cancer tissue were located in the biological Kyoto Encyclopedia of Genes and Genomes pathways and are thought to be candidate biomarkers for targeted therapy.

Human catalytic antibodies with glutathione peroxidase activity

In order to generate catalytic antibodies with glutathione peroxidase (GPx) activity, we prepared GSH-S-DNP butyl ester and GSH-S-DNP benzyl ester as the haptens. Two ScFvs that bound specifically to the haptens were selected from the human phage-displayed antibody library. The two ScFv genes were highly homologous, consisting of 786 bps and belonging to the same VH family-DP25. In the premise of maintaining the amino acid sequence, mutated plasmids were constructed by use of the mutated primers in PCR, and they were over-expressed in E. coli. After the active site serine was converted into selenocysteine with the chemical modifying method, we obtained two human catalytic antibodies with GPx activity of 72.2U/micromol and 28.8U/micromol, respectively. With the aid of computer mimicking, it can be assumed that the antibodies can form dimers and the mutated selenocysteine residue is located in the binding site. Furthermore, the same Ping-Pong mechanism as the natural GPx was observed when the kinetic behavior of the antibody with the higher activity was studied.