Expression of survivin in primary and metastatic gastric cancer cells obtained by laser capture microdissection

AIM:Survivin, a recently identified member of the inhibitor of apoptosis protein family, is expressed during development and in various human cancers. However, its expression in normal tissues and clinical relevance in cancers are still debated. In the present study, we analyzed the expression of the survivin gene in human primary and metastatic gastric cancer cells as well as in paired epithelial cells from normal gastric mucosa by means of a novel laser capture microdissection (LCM) technique coupled with reverse transcription -polymerase chain reaction (RT-PCR).METHODS: Thirty patients who had undergone gastrectomy with lymph node dissection for gastric cancer without preoperative treatments were included. Neoplastic tissue, metastatic lymph nodes, and apparently uninvolved normal tissue were collected from each patient. LCM-captured 'pure' cell groups were respectively subjected to RT-PCR analysis with primers specific for the survivin gene.RESULTS: Of the paired samples from 30 gastric cancer patients studied, 24 (80%) primary gastric cancer cell groups and 7 (23%) adjacent morphologically 'normal' gastric epithelial cell groups were shown to have a detectable survivin expression. There was a statistically significant difference in suvivin expression between these two groups (P<0.01). Meanwhile, 95% (19/20) of the metastatic gastric cancer cell groups from lymph nodes had a clear expression of the survivin gene. However, no significant correlation between survivin expression and clinicopathological features of gastric cancer was observed in the present study. CONCLUSION: Survivin expression is present in the majority of gastric cancer cell groups obtained by LCM techniques. The high expression rate in metastatic lesions suggests a possible role of survivin in cancer invasiveness and metastasis. It may contribute to the detection of gastric cancer micrometastasis as a potential molecular marker. In addition, the high expression percentage renders survivin a potential target in the therapy for gastric cancer.

Association of Fas-670 gene polymorphism with inflammatory bowel disease in Chinese patients

AIM: Recent studies suggest that Fas-mediated apoptosis is involved in the pathogenesis of inflammatory bowel disease (IBD). It has been hypothesized that either increased apoptosis of intestinal epithelium or decreased apoptosis of lamina propria lymphocytes may induce inflammation of gut. The aim of this study was to determine whether the Fas gene promoter polymorphism at position-670 was associated with IBD in Chinese patients.METHODS: Fifty unrelated Chinese patients with IBD (38patients with ulcerative colitis and 12 with Crohn's disease)and 124 healthy controls were genotyped for the Fas-670polymorphism by PCR-restriction fragment length polymorphism method. The PCR product was digested by Mva I restriction enzyme.RESULTS: Distribution of the Fas-670 gene polymorphism was 33% for the AA genotype, 52% for the AG genotype and 15% for the GG genotype in 124 healthy subjects. In patients with IBD, 30% was for the AA genotype, 42% for the AG genotype and 28% for the GG genotype respectively. However, there was no significant difference in the genotype (P= 0.1498), allele frequencies (P= 0.3198)and carriage frequencies (P = 0.4133) between healthy controls and IBD patients. Furthermore, we did not find any difference between the left-sided colitis and total colitis (P = 0.8242).CONCLUSION: Fas-670 polymorphism is not associated with IBD in Chinese patients.

Somatic mutation analysis of p53 and ST7 tumor suppressor genes in gastric carcinoma by DHPLC

AIM: To verify the effectiveness of denaturing highperformance liquid chromatography (DHPLC) in detecting somatic mutation of p53 gene in gastric carcinoma tissues.The superiority of this method has been proved in the detection of germline mutations, but it was not very affirmative with respect to somatic mutations in tumor specimens. ST7 gene, a candidate tumor suppressor gene identified recently at human chromosome 7q31.1, was also detected because LOH at this site has also been widely reported in stomach cancer.METHODS: DNA was extracted from 39 cases of surgical gastric carcinoma specimen and their correspondent normal mucosa. Seven fragments spanning the 11 exons were used to detect the mutation of p53 gene and the four exons reported to have mutations in ST7 gene were amplified by PCR and directly analyzed by DHPLC without mixing with wild-type allele.RESULTS: In the analysis of p53 gene mutation, 9 aberrant DHPLC chromatographies were found in tumor tissues, while their normal-adjacent counterparts running in parallel showed a normal shape. Subsequent sequencing revealed nine sequence variations, 1 polymorphism and 8 mutations including 3 mutations not reported before. The mutation rate of p53 gene (21%) was consistent with that previously reported. Furthermore, no additional aberrant chromatography was found when wild-type DNA was added into the DNA of other 30 tumor samples that showed normal shapes previously. The positivity of p53 mutations was significantly higher in intestinal-type carcinomas (40 %) than that in diffuse-type (8.33 %) carcinomas of the stomach. No mutation of ST7 gene was found.CONCLUSION: DHPLC is a very convenient method for the detection of somatic mutations in gastric carcinoma. The amount of wild type alleles supplied by the non-tumorous cells in gastric tumor specimens is enough to form heteroduplex with mutant alleles for DHPLC detection. ST7 gene may not be the target gene of inactivation at 7q31 site in gastric carcinoma.

Effect of cyclin G2 on proliferative ability of SGC-7901 cell

AIM: To study the effect of cyclin G2 on proliferation of gastric adenocarcinoma cell line-SGC-7901 cell in vitro.METHODS: By use of cation lipofectamine transfection reagent,the pIRES-G2 and pIRESneo plasmids were transferred into SGC-7901cell line. Anticlones were selected by G418. Positive clones were observed and counted using Giemsa staining.Cell proliferative ability was assayed by Ml-r.RESULTS: (1) The done number of pIRES-G2 group decreased,clone volume reduced. The number of cell clones in pIRESneo group was 87+3, that of pIRES-G2 group was 53+4,occupying 60.1% of pIRESneo group, there was significant difference obviously (P<0.01, t=15.45). (2) The average absorbance of clone cell obtained by stable transfection of pIRES-G2 at 570 nm was 1.6966+0.2125, the average absorbance of clone cell obtained by stable transfection of pIRESneo at 570 nm was 2.1182+0.3675, there was significant difference between them (P<0.01, t=3.412).CONCLUSION: Cyclin G2 can inhibit SGC-7901cell proliferative ability obviously, it may be a negative regulator in cell cycle regulation.

《机械制造工艺学》翻转课堂的教学改革

针对机械制造工艺学知识面广、实践性强等特点,突破传统的“满堂灌,填鸭式”教学模式,对理论模块进行翻转课堂的教学改革,通过课堂转移法、教学多样化及教师与企业工程师置换法来提高翻转课堂的氛围与参与度,从而进一步激发了学生学习的自主性,实现了理论与实践完美的融合,使学生的实践能力与解决实际生产问题的能力得到较大的提升,为翻转课堂的教学改革提供了一定的理论基础。

ChinAfrica presents selected Chinese cities with a brief introduction about what makes them interesting,and what makes them tick

LOCATED in the northwest of southwest China＇s Yunnan Province, Lijiang has two faces - one scenic, and the other urban. Its multifaceted nature makes it a perfect Valentine＇s Day destination for sun-seeking couples and singles alike.

Characterization of the Rice Floral Organ Number Mutantfon3

A spontaneous rice mutant named floral organ number 3 (fon3) had major mutations in floral organ numbers. Genetic analysis indicated that fon3 acted as a single recessive gene. Microscopic observation showed that the number of floral organs in fon3 increased centripetally. For example, the number of pistils was the more frequently increased than organs in the outer whorls. Homeotic conversion of lodicules and glumes into palea/lemma-like organs was observed in some flowers. Scanning electron microscopy observation showed that the size of flower meristems was maintained the same or similar until the lemma primordium started to differentiate, at which time the floral meristem became enlarged, suggesting abnormal development of the inner whorls of rice florets. The relationship of fon3 with other similar rice mutants is discussed.

Selection of Proteins for Human MHC Class Ⅱ Presentation

We investigated the predicted function of proteins eluded from human MHC class Ⅱ molecules.Peptides that are presented by MHC class Ⅱ were obtained from the SYFPEITHI database and the corresponding proteins were found in the SWISSPROT database.The functions of these proteins were predicted using the protfun server.Our analysis showed that human proteins presented by MHC class Ⅱ molecules are likely to be in the cell envelope,be a receptor or involved in immune responses.Presented proteins from bacteria and virus,on the other hand,are more likely to be involved in regulatory functions,translation,transcription as well as replication.These results can lead to better understanding the autoimmunity and the response to infections.Cellular & Molecular Immunology.2005; 2(1):49-56.