Construction of a protein-protein interaction network of Wilms' tumor and pathway prediction of molecular complexes.

Wilms' tumor (WT), or nephroblastoma, is the most common malignant renal cancer that affects the pediatric population. Great progress has been achieved in the treatment of WT, but it cannot be cured at present. Nonetheless, a protein-protein interaction network of WT should provide some new ideas and methods. The purpose of this study was to analyze the protein-protein interaction network of WT. We screened the confirmed disease-related genes using the Online Mendelian Inheritance in Man database, created a protein-protein interaction network based on biological function in the Cytoscape software, and detected molecular complexes and relevant pathways that may be included in the network. The results showed that the protein-protein interaction network of WT contains 654 nodes, 1544 edges, and 5 molecular complexes. Among them, complex 1 is predicted to be related to the Jak-STAT signaling pathway, regulation of hematopoiesis by cytokines, cytokine-cytokine receptor interaction, cytokine and inflammatory responses, and hematopoietic cell lineage pathways. Molecular complex 4 shows a correlation of WT with colorectal cancer and the ErbB signaling pathway. The proposed method can provide the bioinformatic foundation for further elucidation of the mechanisms of WT development.

Analysis of the gene-protein interaction network in glioma.

Glioma is the most aggressive type of brain tumor. Great progress has been achieved in glioma treatment, but the protein-protein interaction networks underlining glioma are poorly understood. We identified the protein-protein interaction network for glioma based on gene expression and predicted biological pathways underlying the molecular complexes in the network. Genes involved in glioma were selected from the Online Mendelian Inheritance in Man (OMIM) database. A literature search was performed using the Agilent Literature Search plugin, and Cytoscape was used to establish a protein-protein interaction network. The molecular complexes in the network were detected using the Clusterviz plugin, and pathway enrichment of molecular complexes was performed using DAVID online. There were 378 glioma genes in the OMIM database. The protein-protein interaction network in glioma contained 1814 nodes, 6471 edges, and 8 molecular complexes. There were 17 pathways (false discovery rate <1), which were related to cytokine-cytokine receptor interaction, Toll-like receptor signaling pathway, chemokine signaling pathway, oocyte meiosis, progesterone-mediated oocyte maturation, transmembrane transport of small molecules, metabolism of amino acids, and notch signaling pathway, among others. Our results provide a bioinformatic foundation for further studies of the mechanisms of glioma.

PUMA gene transfection can enhance the sensitivity of epirubicin-induced apoptosis of MCF-7 breast cancer cells.

We explored whether p53 upregulated modulator of apoptosis (PUMA) gene transfection could enhance the sensitivity of epirubicin-induced apoptosis of MCF-7 breast cancer cells. The liposome-mediated recombinant eukaryotic expression vector PU-MA-pCDNA3 and empty vector plasmid were stably transfected into MCF-7 cells. Epirubicin (0.01-100 µM) was applied to MCF-7, MCF-7/PUMA, and MCF-7/pCDNA3 cells for 72 h. The MTT assay was used to calculate the cell survival rate in each group, and the 50% inhibitory concentration (IC50) was calculated. The IC50 values of epirubicin in MCF-7, MCF-7/PUMA, and MCF-7/pCDNA3 cells were 13 ± 1.4, 1.8 ± 0.2, and 10.7 ± 1.3 µM, respectively. The sensitivity of MCF-7/PUMA cells to epirubicin increased 7.2-fold. Epirubicin induced apoptosis in MCF-7 cells dose-dependently, but MCF-7/PUMA cell-induced apoptosis was more significant compared to controls. Low concentrations of epirubicin (0.1 µM) caused low levels of apoptosis of MCF-7/pCDNA3 (1.15 ± 0.26%) and MCF-7 cells (0.9 ± 0.24%), but significantly induced apoptosis of MCF-7/PUMA cells (6.44 ± 1.46%). High epirubicin concentration (1 µM) induced apoptosis in each group, but the epirubicin MCF-7/PUMA apoptosis rate (35.47 ± 9.36%) was significantly higher than that of MCF-7 (12.6 ± 3.73%) and MCF-7/ pCDNA3 (15.2 ± 5.17%) cells (P < 0 01). Flow cytometry and TUNEL assays for apoptosis detection showed similar results. PUMA protein expression in MCF-7/PUMA cells was significantly higher than that in MCF-7 and MCF-7/pCDNA3 cells by Western blot analysis. There-fore, stable transfection of PUMA can significantly enhance epirubicin-induced apoptosis sensitivity of MCF-7 breast cancer cells.

Effect of Rhizoma paridis total saponins on apoptosis of colorectal cancer cells and imbalance of the JAK/STAT3 molecular pathway induced by IL-6 suppression.

We observed the influence of different concentrations of Rhizoma paridis total saponins (RPTS) on the apoptosis of colorectal cancer cells and explored the internal mechanism involved. We determined whether RPTS influences the interleukin-6 (IL-6)/Janus kinase (JAK)-signal transducer and activator of transcription-3 (STAT3) apoptosis molecular pathway and looked for colon cancer-related signal transduction pathways or targets inducing apoptosis. We also cultured SW480 colorectal cancer cells using different concentrations of RPTS (10, 20, 40, and 80 µg/ mL), and observed the effect of RPTS on SW480 cell morphology under a fluorescence inverted microscope. We detected serum IL-6 using the polymerase chain reaction and the expression of JAK-STAT3 protein by western blot. After treating SW480 with RPTS and Hoechst 33258 dyeing, we found that the typical apoptosis morphology had changed. Secretion of IL-6 in the serum decreased significantly (P < 0.05), and STAT3 levels were reduced. RPTS can significantly promote apoptosis in SW480 colorectal cancer cells. The mechanism may be that it suppresses the secretion of IL-6 and inhibits the IL-6/JAK-STAT3 protein signaling pathway.

The relationship of aging to endotoxin shock and to production of TNF-alpha.

BACKGROUND: Aged people are considered prone to gram-negative bacteremia and septic shock. This relationship was tested in murine endotoxin shock. METHODS: Balb/c mice of various ages (1.4-13.4 months) were intraperitoneally injected with lipopolysaccharide (LPS), and rates of survival were observed. The production of TNF-alpha in vivo induced by LPS was measured. RESULTS: The survival rates were the smallest in the oldest and youngest groups. Production of TNF-alpha attained a maximum at 2 h after LPS injection and was smaller in the oldest group; it had a reciprocal relationship to survival rates in each group except the youngest group. CONCLUSION: Old and young mice had smaller rates of survival and greater production of TNF-alpha following endotoxin shock induced by LPS.