[Effect of cobalt chloride on S100A4 expression in human gastric cancer cell BGC823].

S100A4 is an important metastasis-associated gene. Researches have confirmed the close correlation between overexpression of S100A4 gene and gastric cancer's infiltration, lymph node metastasis and in vitro invasiveness of gastric cancer cells. In order to investigate the mechanism of overexpression of S100A4 gene, hypoxia mimetic cobalt chloride (CoCl2) was used to treat gastric cancer cell BGC823, and then the expression of S100A4 mRNA and protein in BGC823 cells were detected by RT-PCR, immunohistochemistry, immunofluorescence, and Western blotting analysis.

Decreased expression of DICER1 in gastric cancer.

Background: The role of epigenetics in gene expression regulation and development significantly enhances our understanding of carcinogenesis. All the tumor related genes may be the target of epigenetical or genetic regulation. We selected some epigenetically regulated genes for cDNA array analysis and observed variability in the expression of the DICER1 gene in distinct stages of gastric cancer.

[Effect of B-RAF-specific RNA interference on gastric cancer BGC823 cell line].

To investigate the influence of B-RAF-specific RNA interference on the proliferation and apoptosis of gastric cancer BGC823 cell line. B-RAF-siRNA and scramble-siRNA were synthesized and transfected into BGC823 cells by TransMessenger. The expression of B-RAF gene and Bcl-2 gene in BGC823 cells was detected by RT-PCR and the level of apoptosis was evaluated in transfected cells by flow cytometry.

Gene expression patterns in gastric cancer.

Objective: To identify gene expression patterns in distinct stages of intestinal-type gastric cancer(GC).

Methods: Gene expression patterns of distinct stages of intestinal-type GC samples from 3 patients were compared with cDNA microarray, which contained 576 genes. There were 506 target genes, which included 51 genes identified from our previous experiment with suppression subtractive hybridization(SSH) and other 455 genes chosen for their important roles in cancers.

Analysis of metastasis suppressing function of E-cadherin in gastric cancer cells by RNAi.

Aim: To study the effect of inhibited E-cadherin expression on invasion of cancer cells.

Methods: We designed the nucleotide sequence of siRNA corresponding to 5' non-coding and coding sequence of E-cadherin. 21-nucleotide dssiRNA was synthesized by in vitro transcription with Ambion Silencer TM siRNA Construction Kit.

[Screening and analysis of associated genes in the carcinogenesis and progression of gastric cancer].

Objective: To screen and analyze the important associated genes in different stages of gastric cancer.

Methods: Using suppression subtractive hybridization (SSH) to screen differentially expressed genes; detecting the expression of genes in different stages of gastric cancer with dot blot hybridization; and verifying the results with semi-quantitative reverse transcriptase-polymerase chain reaction(RT-PCR).

Results: Twenty-six differentially expressed gene fragments were obtained by means of SSH.

[The I1307K mutation and protein expression of APC gene in gastric cancer].

In order to explore the correlation of the abnormalities of tumor suppressor gene APC with the carcinogenesis and progression of gastric cancer. The I1307K mutation of APC gene in gastric cancer was analysed using Amplification Refractory Mutation System PCR(ARMS ,PCR),also the expression of APC protein in gastric cancer of different stages was detected by immunohistochemical method. We found that there wasn't I1307K mutation of APC gene in 62 cases of blood samples of susceptible population in high incidence areas of gastric cancer and 45 cases of gastric cancer tissues.

[Cloning associated genes using microdissection-cDNA PCR-SSH in gastric dysplasia].

Objective: To construct cDNA subtracted libraries from gastric dysplasia and further screen differentially expressed genes.

Methods: Relatively pure dysplasia and normal tissue were procured by manual microdissection, and amplified by cDNA-PCR, which was used to carry on for suppression subtractive hybridization (SSH). Subtracted cDNA fragments were linked with vector, cloned, screened, sequenced, and made homologous search.

[Studies of promoter methylation status and protein expression of E-cadherin gene in associated progression stages of gastric cancer].

Gastric cancer, like all cancers, is considered to result in part from the accumulation of multiple genetic alterations leading to oncogene overexpression and tumour suppressor loss. More recently, the role of epigenetic change as a distinct and crucial mechanism to silence a variety of methylated tissue-specific and imprinted genes has emerged in many cancer types. The study of DNA methylation changes in gastric cancer has now provided additional clues into the pathogenesis of the disease.