Evaluation of TAZ expression and its effect on tumor invasion and metastasis in human glioma

OBJECTIVES@#To evaluate the expression of TAZ and its role in tumor invasion and metastasis in human glioma.@*METHODS@#The expression of TAZ protein was measured in 48 samples of surgically resected human glioma and 13 samples of normal brain tissues using immunohistochemistry. TAZ was knocked down by a retrovirus-mediated TAZ shRNA in a glioma cell line, SNB19. Transwell cell migration and invasion assays were used to determine migration and invasion of SNB19 cells.@*RESULTS@#The positive expression rate of TAZ protein in glioma tissues was significantly higher than that in normal brain tissues (79.2% vs. 15.4%, P<0.001). Furthermore, clinical analysis suggested that the positive expression rate of TAZ protein in poorly differentiated tumor tissues was significantly higher as compared with that in well differentiated tissues (96.0% vs. 60.9%, P<0.01). TAZ was significantly knocked down by TAZ shRNA (P<0.001), and TAZ knockdown significantly reduced cell migration and invasion (P<0.01, respectively) in SNB19 cells.@*CONCLUSIONS@#TAZ protein overexpression is observed in human glioma and its elevated expression is significantly correlated with poor differentiation. TAZ knockdown prominently reduces cell migration and invasion in SNB19 cells, suggesting that TAZ may play a key role in the initiation and progression of human glioma.

Correlation between antifungal agent phenazine-1-carboxylic acid and pyoluteorin biosynthesis in Pseudomonas sp. M18.

Biosynthesis and secretion of two different types of antifungal compound [phenazine-1-carboxylic acid (PCA) and pyoluteorin (Plt) in Pseudomonas sp. M18] contribute to its suppression of soil-borne root pathogens. To better understand the correlation between two antifungal agents in secondary metabolism, a DNA fragment covering partial pltC and pltD coding sequences was obtained by screening the genomic library of Pseudomonas sp. M18. A mutant, M18T, was then constructed by insertion of the aacC1 gene cassette (encoding gentamycin resistance). With the same methods, one PCA biosynthetic gene cluster was insertionally inactivated and a mutant M18Z1 was created. The mutant strain M18T produces no Plt and the same amount of PCA in comparison with the wild-type strain M18. The mutant M18Z1, however, produces less PCA but more Plt than the wild-type strain M18. According to the documented data on strain M18, it is suggested that production of PCA is not influenced by Plt yield, but Plt biosynthesis is influenced by an alteration of PCA production.

Autoinduction of RpoS biosynthesis in the biocontrol strain Pseudomonas sp. M18.

The rpoS gene from Pseudomonas sp. M18, which encodes predicted protein (an alternative sigma factor s, sigma(S), or sigma(38)) with 99.5% sequence identity with RpoS from Pseudomonas aeruginosa PAO1, was first cloned. In order to investigate the mechanism of rpoS expression, an rpoS null mutant, named M18S, was constructed with insertion of aacC1 cassette bearing a gentamycin resistance gene. With introduction of a plasmid containing an rpoS'-'lacZ translational fusion (pMERS) to wild-type strain M18 or M18S, it was first found that beta-galactosidase activity expressed in strain M18S (pMERS) decreased to fourfold of that expressed in the strain M18 (pMERS). When strain M18S (pMERS) was introduced with another plasmid pBBS containing the wild-type rpoS gene, its beta-galactosidase expression level was enhanced and almost restored to that in strain M18 (pMERS). Similarly, expression of beta-galactosidase from a chromosomal fusion of the promoter of the wild-type rpoS gene with lacZ (rpoS-lacZ) was enhanced fivefold in the presence of a plasmid with the wild-type rpoS gene. With these findings, it is suggested that RpoS sigma factor may be involved in autoinducing its own gene expression in Pseudomonas sp. M18.

[Effects of sigma38 subunit deletion of RNA polymerase on antibiotics biosynthesis in pseudomonas].

With the designed primers, PCR was carried out using the genomic DNA of Pseudomonas sp. M18 as a template and a 378bp DNA fragment of the rpoS gene was amplified. Then, a 3. 1kb EcoR I -Xho I fragment containing the rpoS gene and its flanking sequence was obtained by screening the genomic DNA library of Pseudomonas sp. M18.A sigma38-subunit-deficient mutant M18S was constructed with insertional gentamycin gene cassette. In PPM medium, the mutant M18S produced 20.4 microg/mL of PCA and 75 microg/mL of Plt. In KMB medium, the mutant M18S produced no PCA and 185.6 microg/mL of Pit. It is obvious that the deficiency of sigma38 subunit in the mutant M18S leads less or no PCA production and much more Plt production than those in the wild type strain M18. PCA and Plt production were restored to the levels in wild type strain after complementation with rpoS gene in trans in strain M18S. Moreover, beta-galactosidase activities of the translational fusions phzA'-'lacZ and pltA'-'lacZ in strain M18S confirmed the effects of sigma38 subunit on PCA and Plt biosynthetic operons. With these results, it is suggested that sigma38 subunit gives a differential impacts on PCA and Plt biosynthesis, i. e, PCA production is positively regulated but Plt production is negatively influenced by sigma38 subunit in Pseudomonas sp. M18.

Expression and Clinical Significance of bcl-X_L mRNA and Its Protein in Childhood Medulloblastoma / 实用儿科临床杂志

Objective To study the expression level and clinical significance of bcl-XL gene in childhood medulloblastoma.Methods The expression of Bcl-XL protein and bcl-XL mRNA were determined by immunohistochemical staining and in situ hybridization in 41 samples of medulloblastoma tissues,as well as 20 normal brain tissues.Results The positive rate of Bcl-XL protein(90.2%) and bclXL mRNA(95.1%) in medulloblastoma group were significantly higher than those in normal human brain tissues(all P

Expression of Death Receptor 4 and Death Receptor 5 in Human Craniopharyngioma / 实用儿科临床杂志

Objective To investigate the expression and significance of death receptor 4(DR4) and DR5 in human craniopharyngioma.Methods The expression of DR4 and DR5 was determined by immunohistochemistry and in situ hybridization in 28 samples of craniopharyngioma and 25 samples of normal brain tissue.Results With low expression in partial normal brain tissue,DR was expressed highly in all of the craniopharyngioma samples.High DR expression in craniopharyngioma tissue differed from low DR expression in normal brain tissue(P0.05).Conclusions High DR expression is prevalent in craniopharyngioma tissue.This may contribute to the apoptosis-induced therapy of craniopharyngioma.The control of DR expression lays in protein level.This may contribute to the selective induced-apoptosis of tumor necrosis factor-related apoptosis-induced ligand.