Tumor‐suppressive roles of ΔNp63β‐miR‐205 axis in epithelial–mesenchymal transition of oral squamous cell carcinoma via targeting ZEB1 and ZEB2

We previously revealed that epithelial‐to‐mesenchymal transition (EMT) was mediated by ΔNp63β, a splicing variant of ΔNp63, in oral squamous cell carcinoma (OSCC). Recent studies have highlighted the involvement of microRNA (miRNA) in EMT of cancer cells, though the mechanism remains unclear. To identify miRNAs responsible for ΔNp63β‐mediated EMT, miRNA microarray analyses were performed by ΔNp63β‐overexpression in OSCC cells; SQUU‐B, which lacks ΔNp63 expression and displays EMT phenotypes. miRNAs microarray analyses revealed miR‐205 was the most up‐regulated following ΔNp63β‐overexpression. In OSCC cells, miR‐205 expression was positively associated with ΔNp63 and negatively with zinc‐finger E‐box binding homeobox (ZEB) 1 and ZEB2, potential targets of miR‐205. miR‐205 overexpression by miR‐205 mimic transfection into SQUU‐B cells led to decreasing ZEB1, ZEB2, and mesenchymal markers, increasing epithelial markers, and reducing cell motilities, suggesting inhibition of EMT phenotype. Interestingly, the results opposite to this phenomenon were obtained by transfection of miR‐205 inhibitor into OSCC cells, which express ΔNp63 and miR‐205. Furthermore, target protector analyses revealed direct regulation by miR‐205 of ZEB1 and ZEB2 expression. These results showed tumor‐suppressive roles of ΔNp63β and miR‐205 by inhibiting EMT thorough modulating ZEB1 and ZEB2 expression in OSCC.     

Polymyxin-B-binding sites in the cochlea as demonstrated by polymyxin-B/gold labeling

Summary A polymyxin-B/bovine-serum-albumin/gold complex was used as a probe to detect the binding sites of polymyxin B on thin sections of cochlea embedded in Spurr's resin. The binding sites were found to be mainly located on the stereocilia, the cuticular plate of hair cells, the head plate of Deiters' cells, the tonofilaments in pillar cells and Deiters' cells, fibrous structures in the spiral limbus, the tectorial membrane and the basilar membrane and neural elements such as nerve endings, fibers, and the myelin sheath. The mitochondria, plasma mimbrane, and chromatin of the nuclei of the cells observed also exhibited binding. Our results suggest that phospholipids, glycoconjugates, cytoskeletal proteins and nucleic acids are responsible for this binding activity.     

Electrically promoted protein production by mammalian cells cultured on the electrode surface

Protein production of mammalian cells has been promoted by applying a small constant potential to the surface of an electrode on which cells are cultured. Human carcinoma line of MKN45 cells were cultured on the surface of a platinum-coated plastic plate electrode. Low d.c. voltage of constant potential was applied to the electrode during 4-day culture to modulate the production of carcinoembryonic antigen (CEA). The amounts of both secreted and membrane-bound CEA were dependent on the applied potential during culture. Secreted CEA was more than twice in amount in the potential range from 0.2 V to 0.6 V vs. Ag/Agcl as compared with that of normal culture. In the potential range, CEA was also increased in membrane-bound form. The potential-controlled cell culture may have an enhanced effect on protein production.     

Structural and functional analysis of the rat malic enzyme gene promoter.

We have characterized sequences of genomic DNA 5' to the coding region of the rat malic enzyme gene. This sequence possesses neither TATA nor CCAAT sequences in their usual positions but is rich in GC residues. Sequences similar to those found in the regulatory regions of other genes are discussed. Deletion analyses have revealed that sequences +1 to -41 are sufficient to initiate expression, although inclusion of information up to -177 is necessary for maximal promoter activity.     

Production of swine pepsinogen by protein-producing Bacillus brevis carrying swine pepsinogen cDNA

Summary An expression-secretion vector, pNU100, was constructed, utilizing the promoter and coding sequences for the signal peptide and nine amino-terminal amino acids of the middle wall protein, to produce foreign proteins by protein-producing Bacillus brevis. Expression of swine pepsinogen cDNA in B. brevis was examined with pNU100 as a vector. The recombinant swine pepsinogen synthesized by B. brevis was found to accumulate extracellularly in the form of a soluble protein and to have acid protease activity. The acid protease activity was completely inhibited by pepstatin. Furthermore, the recombinant pepsinogen was converted autocatalytically to pepsin under acidic conditions. This indicates that B. brevis produces a pepsinogen with the same conformation as authentic pepsinogen. Efficient production of the enzyme (11 mg/l) was achieved by regulating the pH of the medium. The enzyme produced by B. brevis remained stable on cultivation for a long period, up to 40 h. This is suggested to be due to a unique property of protein-producing B. brevis, i. e. a deficiency in extracellular protease production.     

A thermoresistant mutant of ribonuclease T1 having three disulfide bonds

Molecular-dynamic calculations predict that, if Tyr24 and Asn84 are each replaced by a Cys residue, it should be possible to form a third disulfide bond in ribonuclease T1 (RNase T1) between these residues, with only minimal conformational changes at the catalytic site. The gene encoding such a mutant variant of RNase T1 (Tyr24----Cys24, Asn84----Cys84) was constructed by the cassette mutagenesis method using a chemically synthesized gene. In order to reduce the toxic effect of the mutant enzyme (RNase T1S) on an Escherichia coli host, we arranged for the protein to be secreted into the periplasmic space by using a vector that harbors a gene for an alkaline phosphatase signal peptide under the control of the trp promoter. The nucleolytic activity of RNase T1S toward pGpC was approximately the same as that of RNase T1 at 37 degrees C (pH 7.5). Moreover, at 55 degrees C, RNase T1S retained nearly 70% of its activity while the activity of the wild-type enzyme was reduced to less than 10%. RNase T1S was also more resistant to denaturation by urea than the wild-type enzyme. However, unlike RNase T1, RNase T1S was irreversibly and almost totally inactivated by boiling at 100 degrees C for 15 min.     

Predicting state transitions in the transcriptome and metabolome using a linear dynamical system model

Background  

Modelling of time series data should not be an approximation of input data profiles, but rather be able to detect and evaluate dynamical changes in the time series data. Objective criteria that can be used to evaluate dynamical changes in data are therefore important to filter experimental noise and to enable extraction of unexpected, biologically important information.     

Continuous large-scale production of the cytokine CXCL8 from a novel porcine cell line

Cytokine production from two unstimulated porcine cell lines (SL-24 and SK-L) was examined using porcine cytokine detection ELISA kits and RT-PCR. Porcine IL-1 alpha, IL-6, and CXCL8 were detected in all samples examined. In particular, the SL-24 cell line (derived from bone marrow cells of a malignant lymphoma-affected pig), produced large amounts of porcine CXCL8. Flow cytometer analysis showed the cell line to be strongly CD44 positive, and was therefore considered to be of monocyte or macrophage origin. Porcine CXCL8 production was greatest (83.86 +/- 32.33 ng/mL) at six days post-cultivation. The SK-L cell line (derived from porcine kidney) also produced CXCL8, but production was less than 1.5 ng/mL. Porcine CXCL8 from the SL-24 cell line, induced chemotactic activity in porcine neutrophils, while the production of CXCL8 from the SL-24 cell line was inhibited by dexamethasone, which suggests that the mechanism of CXCL8 production is related to an NF-kappaB binding site. The production of CXCL8 from the SL-24 cell line was enhanced by the addition of recombinant porcine IL-15, which is the first reported observation of such CXCL8 production. Cloning of the SL-24 cell line by limited dilution revealed two types of cells present in the starting population. One cell type, designated as long-form cells (LC), produced large amounts of CXCL8, while the other, designated short-form cells (SC), produced small amounts of the cytokine. The LC cells were adapted to grow in serum-free medium in which they produced large amounts of CXCL8. The large-scale production of porcine CXCL8 from the SL-24 cell line will be of value in determining the mechanism of cytokine production and as a source of naturally produced porcine CXCL8.     

CB 1/2 dual agonists with 3-carbamoyl 2-pyridone derivatives as antipruritics: reduction of CNS side effects by introducing polar functional groups

Our lead compound 1 showed high affinity for both CB1 and CB2 receptors, suggesting the possibility of inducing psychoactive side effects through the CB1 receptor in the brain. To solve this issue, polar functional groups were introduced at the 3-position of the pyridone core of compound 1 to find CB1/2 dual agonists such as 17 and 20 which did not show any CNS side effects.