The DLC-1 -29A/T polymorphism is not associated with nasopharyngeal carcinoma risk in Chinese population.

Deleted in liver cancer-1 (DLC-1), encoding a Rho GTPase-activating protein (GAP), is considered as a promising candidate tumor suppressor gene in nasopharyngeal carcinoma (NPC). The single-nucleotide polymorphism (SNP) -29A/T upstream of ATG start codon was found when gene mutation profile of DLC-1 in NPC was analyzed. To evaluate the correlation between SNP -29A/T in the promoter region of DLC-1 gene and risk of NPC, a total of 521 samples from a Chinese population, including 320 healthy individuals and 201 NPC patients, were collected for SNP analysis by PCR-single-strand conformation polymorphism and sequencing. The differences in allele and genotype frequencies between NPC patients and controls were tested using logistic regression statistical method. No significant differences were found in allele or genotype frequencies between NPC patients and controls or among different NPC clinical stages. Hence, our data indicate that the SNP -29A/T of DLC-1 gene is not associated with NPC susceptibility.

[Effect of rosiglitazone on NO and eNOS via PI3K/PKB signal pathways in cultured human umbilical vein endothelial cells].

OBJECTIVE: To observe the effect of rosiglitazone on the production of nitric oxide (NO) and the expression of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB) /the endothelial nitric oxide synthase (eNOS) in cultured human umbilical vein endothelial cells(HUVECs), and to investigate the mechanism of signal transduction of rosiglitazone in improving the endothelial function. METHODS: HUVECs were treated with various concentrations of rosiglitazone. The NO level was measured using Griess Reaction in cell culture supernatants; the expressions of PI3K-, PKB- and eNOS mRNA were measured using RT-PCR; and the expressions of PKB, eNOS, and phosphorylation of PKB-Ser473, eNOS-Ser1177 were measured using Western Blot. RESULTS: Rosiglitazone increased the endothelial NO production in a dose- and time-dependent manner in cultured HUVECs, and also increased the expression of PI3K mRNA and the phosphorylation of PKB-Ser473 and eNOS-Ser1177 in a concentration-dependent manner, with no alteration in the expression of PKB and eNOS in cultured HUVECs. N(w)-nitro-L- arginine methyl ester (L-NAME, eNOS synthase inhibitor) blocked the rosiglitazone-induced NO formation; LY294002 (a PI3K inhibitor) prevented the NO production; and the phosphorylation of eNOS and PKB was induced by rosiglitazone. CONCLUSION: Treatment with rosiglitazone can increase the NO production and improve the endothelial function through up-regulating the PI3K/PKB/eNOS signal pathways in cultured HUVECs.

[PTX1 in nasopharyngeal carcinoma by RNAi technology].

OBJECTIVE: To explore the expression and the role of PTX1 located at the amplified 12p12-p11 region in nasopharyngeal carcinoma (NPC). METHODS: Semi-quantitative RT-PCR and real-time RT-PCR were applied to detect the expression level of PTX1 in 36 NPC and 8 chronic nasopharyngitis (NP) biopsies. RNAi vector targeting PTX1 was constructed and transfected into NPC cell line 6-10B. The RNAi effect was determined by detecting the expression level of PTX1 in transfected 6-10B cell line. Finally, the cell biological characteristics were compared between transfected 6-10B and parental 6-10B by analyzing the cell cycle distribution and apoptosis status using flow cytometry. RESULTS: RT-PCR and real-time RT-PCR revealed that PTX1 gene was over-expressed in NPC tissues (P<0.05). PTX1 expression was suppressed in NPC cell line 6-10B by approximately 65% by RNAi, confirmed by RT-PCR. The depletion of PTX1 could effectively block the proliferation and induce the apoptosis of NPC cells. CONCLUSION: Blocking the expression of PTX1 on mRNA level changed the characterization of NPC cell line 6-10B by RNAi, suggesting that PTX1 identified in the amplified 12p12-p11 region may be involved in the genesis and development of NPC via promoting the cell proliferation and inhibiting the cell apoptosis.

STAT3 signal that mediates the neural plasticity is involved in willed-movement training in focal ischemic rats.

Willed-movement training has been demonstrated to be a promising approach to increase motor performance and neural plasticity in ischemic rats. However, little is known regarding the molecular signals that are involved in neural plasticity following willed-movement training. To investigate the potential signals related to neural plasticity following willed-movement training, littermate rats were randomly assigned into three groups: middle cerebral artery occlusion, environmental modification, and willed-movement training. The infarct volume was measured 18 d after occlusion of the right middle cerebral artery. Reverse transcription-polymerase chain reaction (PCR) and immunofluorescence staining were used to detect the changes in the signal transducer and activator of transcription 3 (STAT3) mRNA and protein, respectively. A chromatin immunoprecipitation was used to investigate whether STAT3 bound to plasticity-related genes, such as brain-derived neurotrophic factor (BDNF), synaptophysin, and protein interacting with C kinase 1 (PICK1). In this study, we demonstrated that STAT3 mRNA and protein were markedly increased following 15-d willed-movement training in the ischemic hemispheres of the treated rats. STAT3 bound to BDNF, PICK1, and synaptophysin promoters in the neocortical cells of rats. These data suggest that the increased STAT3 levels after willed-movement training might play critical roles in the neural plasticity by directly regulating plasticity-related genes.

[Construction of N-LMP1 transgenic mice with the specific regulation region in nasopharynx].

In order to elucidate the role of EBV-LMP1 in the nasopharyngeal carcinogenesis, the expression vector was constructed with subjecting the N-LMP1 gene to double regulation of two specific regulators: EDL-2 and PLUNC-p. The N-LMP1 related transgenic mice model has been constructed successfully by pronucleus microinjection. 58 founder mice were born, 4 of which were founded to be positive by PCR and Southern blot. Immunohistochemistry assay showed that N-LMP1 protein was expressed in the nasopharynx, tongue and forestomach of transgenic mice.

[Effects of site-directed mutagenesis at amino acid residues of GATA-1b different from that of GATA-1a in Xenopus].

The GATA-1 of Xenopus (xGATA-1), which has two subtypes xGATA-1a and xGATA-1b, is a necessary factor for erythroid differentiation and maturation as similar as that of other GATA-1s. Although both xGATa-1a and xGATA-1b are able to stimulate erythropoiesis, only xGATA-1b is capable of inhibiting neurogenesis in Xenopus embryos. Compared between their structures, xGATA-1a and xGATA-1b are very similar in nucleotide and amino acids composition, but not identical. Therefore, it is responsible for studying the role of the diverse codons between the two genes, so the desired mutations: S(168), H(169) double deletion and point mutation of T(304)-->A, T(359)-->A, were introduced into xGATA-1b gene through site-directed mutagenesis. Then, mRNA from each mutant as well as wtxGATA-1b was co-injected with DN-BR mRNA or separately injected into Xenopus stage 2 embryos, and the role of mutants in erythropoiesis and neurogenesis was analyzed by using animal cap culture system. The results showed that the neural-inhibiting activity of xGATA-1b, but not hematopoiesis-inducing activity, was aborted because of deletion of Ser(168) and His(169) or point mutation of T(359)-->A. So it is demonstrated for the first time that Ser(168) and His(169) or Thr(359)in xGATA-1b may be one of the structural basis for explanting the different function between xGATA-1b and xGATA-1a.

[Establishment of transgenic Xenopus laevis by intracytoplasmic sperm injection].

OBJECTIVE: To study the feasibility of establishing transgenic laevis by intracytoplasmic sperm injection (ICSI). METHODS: The testes of mature Xenopus laevis were taken for the purification of their sperms, which was subsequently incubated with digitonin to prepare concentrate of the sperms. Treatment of the concentrate with linearized reporter vector pCMV-EGFP-N1 was performed, and the sperms were then injected into unfertilized ova harvested from female laevis, followed by culture and observation of the development of the ova. RESULTS: The condensed sperm we obtained were of high quality and after intracytoplasmic injection into the ova, a fertilization rate of 10% was achieved and 20% of the zygotes survived the neurula stages and developed into tadpoles, but all of which were slightly deformed. The integration ratio of green fluorescent protein (GFP) reporter gene was 81%, but GFP expression was not observed in the laevis. CONCLUSION: ICSI is a simple and practicable method for establishing transgenic Xenopus laevis.

Genome-wide analysis of DNA methylation in tongue squamous cell carcinoma.

Tongue squamous cell carcinoma (TSCC) is one of the most common types of oral cancer; however, its molecular mechanisms remain unclear. In this study, methylated DNA immunoprecipitation (MeDIP) coupled with methylation microarray analysis was performed to screen for aberrantly methylated genes in adjacent normal control and TSCC tissues from 9 patients. Roche NimbleGen Human DNA Methylation 385K Promoter Plus CpG Island Arrays were used to detect 28,226 CpG sites. A total of 1,269 hypermethylated CpG sites covering 330 genes and 1,385 hypomethylated CpG sites covering 321 genes were found in TSCC tissue, compared to the adjacent normal tissue. Furthermore, we chose three candidate genes (FBLN1, ITIH5 and RUNX3) and validated the DNA methylation status by methylation-specific PCR (MS-PCR) and the mRNA expression levels by reverse transcription PCR (RT-PCR). In TSCC tissue, FBLN1 and ITIH5 were shown to be hypermethylated and their expression was found to be decreased, and RUNX3 was shown to be hypomethylated, however, its mRNA expression was found to be increased. In addition, another three genes (BCL2L14, CDCP1 and DIRAS3) were tested by RT-PCR. In TSCC tissue, BCL2L14 and CDCP1 expressions were markedly upregulated, and DIRAS3 expression was significantly downregulated. Our data demonstrated that aberrant DNA methylation is observed in TSCC tissue and plays an important role in the tumorigenesis, development and progression of TSCC.

[Detection of RNA interference in nasopharyngeal carcinoma cell lines using reporter genes].

BACKGROUND & OBJECTIVE: RNA interference (RNAi) technique is now widely used in studies of gene function, signal transduction pathway, and gene therapy because it can effectively and specifically inhibit gene expression. This study was designed to synthesize small interfering RNA (siRNA) by in vitro transcription, and construct retrovirus vectors to express small hairpin RNA (shRNA), detect RNAi in nasopharyngeal carcinoma cell lines, and to develop a RNAi technique platform. METHODS: siRNAs targeting green fluorescent protein (GFP) and luciferase (Luc) were synthesized by in vitro transcription, while shRNAs targeting GFP and Luc were constructed from pSUPER.retro. Cervical cancer cell line HeLa, nasopharyngeal carcinoma cell lines CNE1, CNE2, and 5-8F were co-transfected with siRNAs or shRNAs and reporter gene pEGFP-N1 or pGL3. The expression of GFP was detected by fluorescent microscopy and Western blot. The activity of luciferase was measured by Luciferase Enzyme Assay System. RESULTS: siRNA duplexes with 3' UU overhangs and shRNA specifically silenced GFP expression, while antisense RNA and siRNA without 3' UU overhangs did not trigger RNA interference of GFP. Quantitative luciferase activity analysis showed that siRNA inhibited Luc expression in HeLa, CNE1, CNE2, and 5-8F cell lines with inhibition rates of 91.43%, 78.01%, 90.30%, and 62.85%, respectively. Similarly, the inhibition rate was 78.22% when shRNA targeting Luc was co-transfected into HeLa cell line. CONCLUSIONS: Both siRNAs and shRNAs can induce RNAi. 3' UU overhangs of siRNA may play a role in RNAi. RNAi can be triggered in both nasopharyngeal carcinoma cell lines and HeLa cell line.

Critical role of Cys168 in noggin protein's biological function.

Previous studies have indicated that noggin exerts its neural inducing effect by binding and antagonizing bone morphogenetic protein 4 (BMP4). In order to further clarify the relationship between the structure and the function of noggin, and elucidate the possible mechanism responsible for noggin-BMP4 interaction, we generated three noggin mutants, C168S, C174S and C197S, by using a site-directed mutagenesis method. Ectopic expression of wild-type (WT) noggin, C174S or C197S, in Xenopus animal caps (ACs) by mRNA injection converted the explants (prospective ectoderm) into neural tissue, as indicated by the neural-like morphology and expression of the neural cell adhesion molecule (NCAM) in the ACs. In contrast, ACs expressing C168S suffered an epidermal fate similar to the control caps. Similarly, among the three mutants, only C168S lost the dorsalizing function. These studies highlight the critical role played by Cys168 in noggin's biological activities. It probably participates in the formation of an intermolecular disulfide bridge.

[Analysis of characteristics of gene expression in pericancerous stromal cells of nasopharyngeal carcinoma by cDNA array].

BACKGROUND & OBJECTIVE: The mechanism of how stromal cell play an important role in nasopharyngeal carcinogenesis is now a hotspot. This study was designed to elucidate the possible mechanism of stromal cell in the occurrence and progression of nasopharyngeal carcinoma (NPC) through the analysis of the characteristics of gene expression in pericancerous stromal cells of NPC by cDNA array. METHODS: The atlas human select tumor arrays were used to compare the expression profiles between NPC tissue and NPC cell lines. RESULTS: Pericancerous stromal cells in NPC expressed at least 40 genes specifically. CONCLUSION: The specific expression of these genes in pericancerous stromal cells provides energy materials for growth of NPC cells; furthermore, it can accelerate the degradation of extracellular matrix, thus promoting the metastasis of NPC cells.