DNA methylation and carcinogenesis in digestive neoplasms

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Potential effect of hepatitis C Virus non-structural protein 4B on liver carcinogenesis

Objective：To investigate the effect of hepatitis C virus non-structural protein 4B（HCV NS4B） on c-Myc, P53, ras gene expression＂ and apoptosis in hepatic cells and study the possible role that NS4B played in the carcinogenesis of heparoma. Methods： The recombinant plasmid（PCXN2-NS4B, PCXN2-P53） and the empty, vector were transfected or co-transfected into Chang liver cells with liposome. Screening was performed with G418. Plasmid mRNA was detected by RT-PCR. The pro rein expressions of c-Myc and ras genes were analyzed by immunocytochemistry. The expressions of wild-type P53 （wtp53） gene were detected by in situ hybridization. TUNEL（flow cytometry） was used for assessing the rate of apoptosis. Results：No expression of c-Myc gene was found in PCXN2 group. The expression of c-Myc gene in NS4B group was 21.3% ＋ 1.2%. The ex pression of ras gene in PCXN2 group was lower than that in NS4B group. Compared with PCXN2 group, the expression of P53 mRNA was not promoted or inhibited in NS4B group. But the expression of P53 mRNA in NS4B-P53 group was lower than that in P53 group. In PCXN2, NS4B, P53 and NS4B-P53 group, the rates of apoptosis were 17.02% ± 1.24%, 11.94% ± 2.24%, 25.84% ± 3.49% and 18.34% ± 1.55% respectively. Conclusion ：HCV NS4B induces the expression of c-Myc and ras gene. HCV NS4B may play a role in the inhibition of cell death through P53-dependent manner. Results from this study suggested that HCV NS4B might contribute to the viral carcinogenesis.

Changes of p53 and Waf1p21 and cell proliferation in esophageal carcinogenesis

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The Structural Proteins of Bdellovibrio bacteriovorus Bacteriophage MAC-1

In the present investigation the structural proteins associated with MAC-1 bacteriophage have been characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE);tandem mass spectrometry of protein bands from SDS-PAGE gel;from the open reading frames (ORFs) deduced from MAC-1 genome sequence and amino acid sequence homology searches from the Uniprot database (up000002418). Results have led to the identification of at least three structural proteins associated with MAC-1 phage genome. They are: capsid protein (~55,000-daltons);spike protein (~22,000-daltons) and a low molecular weight DNA binding protein (~4000-dal- tons). In addition, two other minor proteins were tentatively identified as replicative and scaffold proteins based on two to three unique peptides from mass spectrometry data. However, other proteins coded (ORFs) by phage genome remain to be identified.

Promoter hypermethylation of tissue specific tumor supressor genes and point mutation in K-ras, c-myc proto-oncogenes in urinary (transitional cell) bladder carcinoma

In a total of 83 UN specimens were investigated for proto-oncogene mutations, tumor supressor genes promoter methylation status and c-myc and Ki-67 expression. Point mutations in c-myc were detected in cases with high grade and proliferation index. Mutated K-ras proto-onco- gene profiles were detected in 17 (21%) tumoral spiecemens that examined. Tumor specimens were also showed hypermethylated promoter domain for the SFRP2, MGMT tumor supressor genes. These findings showed the combine effect of mutated c-myc and K-ras oncogene and epigenetic inactivation of tissue specific tumor supressor genes (TS) play a crucial role in tumor progression and recurrence in UN carcinogenesis.

Effects of endotoxin on expression of ras, p53 and bcl-2 oncoprotein in hepatocarcinogenesis induced by thioacetamide in rats

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Characterization of six tumorsuppressor genes and microsatellite instability in hepatocellular carcinomain southern African blacks

AIM To analyse cumulative loss of heterozygosity (LOH) of chromosomal regions and tumor suppressor genes in hepatocellular carcinomas (HCCs) from 20 southern African blacks. METHODS p53, RB1, BRCA1, BRCA2, WT1 and E cadherin genes were analysed for LOH, and p53 gene was also analysed for the codon 249 mutation, in tumor and adjacent non tumorous liver tissues using molecular techniques and 10 polymorphic microsatellite markers. RESULTS p53 codon 249 mutation was found in 25% of the subjects, as was expected, because many patients were from Mozambique, a country with high aflatoxin B 1 exposure. LOH was found at the RB1, BRCA2 and WT1 loci in 20%(4/*!20) of the HCCs, supporting a possible role of these genes in HCC. No LOH was evident in any of the remaining genes. Reports of mutations of p53 and RB1 genes in combination, described in other populations, were not confirmed in this study. Change in microsatellite repeat number was noted at 9/*!10 microsatellite loci in different HCCs, and changes at two or more loci were detected in 15%(3/*!20) of subjects. CONCLUSION We propose that microsatellite/genomic instability may play a role in the pathogenesis of a subset of HCCs in black Africans.

In situ detection of tumor infiltrating lymphocytes expressing perforin and fas-ligand genes in human HCC

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Pathological differential diagnosis of solid-pseudopapillary neoplasm and endocrine tumors of the pancreas

AIM:To investigate differential points of solid-pseudo-papillary neoplasm (SPN) of the pancreas and pancre-atic endocrine tumor (PET).METHODS:Ten cases of SPN and fourteen cases of PET were studied in this retrospective study. Clinical and pathologic features,immunostaining reactions and β-catenin gene mutations were analyzed.RESULTS:The mean age of SPN patients was 25.6 years and these patients had no specific symptoms. The mean diameter of the tumors was 11.0 cm,9/10 cases were cystic or a mixture of solid and cystic structures,and there was hemorrhage and necrosis on the cut surface in 8/10 (80%) cases. Characteristic pseudo-papillary structure and discohesive appearance of the neoplastic cells were observed in all 10 (100%) cases. The results of immunostaining showed that nuclear expression of β-catenin and loss of E-cadherin in all the cases,was only seen in SPN. Molecular studies discov-ered that 9/10 (90%) cases harbored a point mutation of exon 3 in β-catenin gene. On the other hand,the mean age of PET patients was 43.1 years. Eight of 14 cases presented with symptoms caused by hypoglyce-mia,and the other 6 cases presented with symptoms similar to those of SPN. The mean size of the tumors was 2.9 cm,most of the tumors were solid,only 3/14 (21%) were a mixture of solid and cystic structures,and macroscopic hemorrhage and necrosis were much less common (3/14,21%). Histologically,tumor cells were arranged in trabecular,acinar or solid patterns and demonstrated no pseudopapillary structure and discohesive appearance in all 14 (100%) cases. The results of immunostaining and mutation detection were completely different with SPN that membrane and cytoplastic expression of β-catenin without loss of E-cadherin,as well as no mutation in β-catenin gene in all the cases. CONCLUSION:Both macroscopic and microscopic features of SPN are quite characteristic. It is not difficult to distinguish it from PET. If necessary,immunos-taining of β-catenin and E-cadherin is quite helpful to make the differential diagnosis.

Cloning of differentially expressed genes in human hepatocellular carcinoma and nontumor liver

INTRODUCTIONThe mechanism of hepatocellular carcinoma(HCC)is still unclear,although some genes have been found to play a role in the transformation of liver cells,and a variety of studies have described differences in gene expression which distinguished tumor from nontumor[1-6].The new genes,especially the functional genes directly related with tumor are still worth being found.The purpose of our study is to find the different genes between human liver tumor and normal tissues using suppression subtractive hybridization.

Differentially expressed genes in hepatocellular carcinoma induced by woodchuck hepatitis B virus in mice

INTRODUCTIONHepatocellular carcinoma(HCC)is one of the major causes of death in the word.The mechanism of carcinogenesis is unknown,although it is widely accepted that HBV and HCV are clsely related to liver cancer[1-5[1-5].Previously,a variety of studies have described the differences in gene expression which distinguished tumor from nontumor[6-11].Cloning of the genes,especially the genes associated with HBV and HCV,is still very important to account for the development of liver cancer.

The expression of c-src gene in the carcinogenesis process of human cardia adenocarcinoma

AIM To investigate the activation, expression of c src gene and its role in the carcinogenetic process of human cardia adenocarcinoma (CA). METHODS Fifty six cases of CA, 34 cases of normal, 36 cases of protiferative epithelia adjacent to carcinoma, and 20 cases of lymph node metastases of CA were studied for PP60 c src , the expression product of c src gene immunohistochemically by using the specific monoclonal antibody, Mab327. RESULTS The positive rates of PP60 c src in the normal epithelia, protiferative epithelia, CA and lymph node metastases were 29 4% (10/*!34), 94 4% (34/*!36), 71 4% (40/*!56) and 60 0% (12/*!20) , respectively, among them, the differences of the positive rates were statistically significant ( P <0 01) . The expression levels of PP60 c src in CA and proliferative epithelia were significantly higher than that in the normal epithelia ( P <0 01) . The PP60 c src positive rates in the papillary, tubular, poorly differentiated and mucous adenocarcinoma were 75 0% (6/*!8) , 81 8% (18/*!22) , 50 0% (10/*!20) and 100 0% (6/*!6) , respectively, whereas those of tubular and mucous adenocarcinomas were significantly higher than those of papillary and poorly differentiated adenocarcinomas ( P <0 05) , and the PP60 c src expression levels of tubular and mucous adenocarcinomas were also significantly higher than those of papillary and poorly differentiated adenocarcinomas ( P <0 01) . CONCLUSION The activation and expression of c src gene are associated with the initiation and development of human CA; the protein amount of PP60 c src increased during the process of carcinogenesis; and PP60 c src expression is also related to lymph node metastases.

Dissemination and Genetic Structure of Carbapenemase Encoding Genes (bla_OXA-23and bla_OXA-24) in <i>Acinetobacter baumannii</i>from Southern Texas

Acinetobacter baumannii is one of the most important human pathogens causing a variety of nosocomial infections. Carbapenem antibiotics have been primarily used to treat the A. baumannii infections. However, carbapenem resistant A. baumannii producing carbapenemases causes serious treatment problems worldwide. Outbreaks of carbapenem resistant isolates have reported in some area of the United States, but their dissemination and genetic structure of the carbapenemase encoding genes are currently little known. To understand outbreaks, dissemination, and genetic structure of the carbapenemase encoding genes in Southern Texas, 32 clinical isolates collected from Austin and Houston, TX were characterized. Twenty-eight of 32 isolates were resistant to all tested β-lactam antibiotics including carbapenem (imipenem and meropenem). Three of them carried blaOXA-23 as a part of Tn2008 integrated into a known plasmid (pACICU2) and all others carried blaOXA-24 flanked by XerC/XerD-like recombinase binding sites that were adjoined by DNA sequences originated from multiple plasmids. Genotype analysis revealed that the 25 isolates carrying blaOXA-24 were all identical genotypes same as a representative isolate carrying blaOXA-24 from Chicago, IL but the 3 isolates carrying blaOXA-23 was a distinct genotype as compared with isolates carrying blaOXA-23 from Chicago, IL and Washington, D.C. Each of the blaOXA-23 and blaOXA-24 was transferred to carbapenem susceptible A. baumannii and E. coli with similar minimal inhibitory concentration (MIC) of carbapenem as that of their parental isolates but significantly lower levels of MIC in E. coli. Overall results suggest that a unique strain carrying blaOXA-23 and a similar strain carrying blaOXA-24 as seen in other geographic areas are currently disseminated in Southern Texas.

EXPRESSION OF GST-л GENE IN HUMAN ESOPHAGEALCARCINOGENESIS

Objective: To investigate the possible role of GST-n in esophageal carcinogenesis. Methods: GST-nexpression at mRNA level was studied by in situhybridization (ISH) and at protein level byimmunohistochemistry (IHC). GST-n expression innormal epithelial cells (NC) of the esophagus,hyperplastic cells (HC), dysplastic cells (DC) from gradeI to III, carcinoma in situ (CIS) and all the cells insquamous cell carcinomas (SCC) were examined in thesame csophageal cancer specimens (n=48) whichprovided a model reflecting the process of esophagealcarcinogenesis. Results: The positive rate of IHCstaining was 87. 5% for NC, 95.3% for HC, 55.9% forDC (grade I: 73.9%, grade II: 47.4%, grade III:41.2%),36.4% for CIS and 45.8% for SCC. The positive rate ofGST-x mRNA expression was 81.2% for NC, 94.4% forHC, 61.9% for DC (grade I: 76.5%, grade II: 61.5%,grade III: 41.7%), 44.4% for CIS and 83.3% for grade ISCC, 30.0% for grade II SCC and 0% for grade IIISCC. There was no statistically sigllificant difference inGST-x expression at the mRNA and the protein level.Conclusion: There is a decreasing tendency of GST-nexpression from dysplasia to CIS and SCC. Thedecrease in GST-n expression is an early event inesophageal carcinogencsis.

Myeloproliferative neoplasms complicated withβ-thalassemia:Two case report

BACKGROUND BCR-ABL-negative myeloproliferative neoplasms(MPNs)are clonal hematopoietic stem cell disorders characterized by the proliferation of one or more myeloid lineages and by mutually exclusive JAK2 V617F,CALR,and MPL[A1]mutations.The combination of MPN and thalassemia is extremely unusual.Several cases with myeloproliferative neoplasms andβ-thalassemia have been reported.However,these have not been extensively reviewed.The present report describes two cases of myeloproliferative neoplasms complicated withβ-thalassemia and reviews all similar cases reported in the literature.CASE SUMMARY We report two patients who were diagnosed with myeloproliferative neoplasms complicated withβ-thalassemia.Both patients had abnormal increases in platelet counts.Based on bone marrow pathology and molecular biology assessment,we made the diagnosis of myeloproliferative neoplasms complicated withβ-thalassemia.The female patient was given hydroxyurea and interferon,which enabled good control of her blood counts;the male patient was given ruxolitinib tablets,thalidomide tablets,and interferon to control the condition,but the patient poorly responded to drug treatment and died of gastrointestinal bleeding six months later.CONCLUSION Given the findings of our cases and the literature review,we hypothesize that myeloproliferative neoplasms complicated withβ-thalassemia can lead to rapid disease progression and a poor prognosis.

EXPRESSION AND REVERSION OF DRUG RESISTANCE-AND APOPTOSIS-RELATED GENES OF A DDP-RESISTANT LUNG ADENOCARCINOMA CELL LINE

Objective: To investigate the co-expression of drug resistance- and apoptosis-related genes of cisplatin (CDDP)-selected lung adenocarcinoma cell line A 549 DDP for compared to the parental cell line A549, and reverse of drug resistance by antisense s-oligodeoxynucleotides (S-ODNs) of differentially expressed genes. Methods: Sense and antisense S-ODN were transferred into A 549 DDP cells by lipofectin. The expression of drug resistance and apoptosis related genes was examined by RT-PCR, immunocytochemistry and flow cytometry, respectively. Apoptostic cells were identified by DNA electrophoresis and terminal deoxynucleotidyl transferase (TdT)-mediated biotin dUTP nick end-labeling(TUNEL). Drug resistance of tumor cells was detected by a cell viability (MTT) assay. Results: The expression of bcl-2 was positive and that of multidrug resistance-associated protein (MRP) at mRNA and protein level was increased in A 549 DDP compared to A549 cells. MDR1, c-myc and topoisomeras II (TOPO II) were similarly co-expressed in two cell lines. Both cell lines were negative for c-erbB-2 expression. In A 549 DDP cells, the expression of bcl-2 and MRP was significantly inhibited by their respective antisense S-ODNs. Antisense S-ODNs could also decrease significantly drug resistance of A 549 DDP cells to CDDP by promoting cell apoptosis. Conclusion: Both intrinsic and acquired drug resistance were involved in co-expression of multiple MDR-related genes in lung adenocarcinoma. Cooperation of bcl-2 and MRP genes appeared to play an important action to confer the resistance of A 549 DDP cells to CDDP. Their antisense S-ODNs are responsible for the decrease of drug resistance of this cell line by promoting apoptosis.

Genetic Evaluation of Starch Synthesis-Related Genes and Starch Quality Traits in Special Rice Resources

The genetic diversity of 36 rice landraces and 43 breeding materials in the upper reaches of the Yangtze River in China was studied by intragenic molecular markers of 26 starch synthesis-related loci.And research on quality traits such as the amylose content(AC),gel consistency(GC)and alkali spreading value(ASV)to analyze genetic differences in quality traits.The results showed that the number of alleles,average gene diversity and polymorphism information content values of landraces were higher than those of breeding materials.The genetic similarity coefficient(GS)of 79 rice materials ranged from 0.392 to 1,with an average of 0.757.There were significant variations in the quality traits of rice landraces and breeding materials,and the high-quality compliance rates were low,only 6.3%of the varieties have an amylose content that reached grade 1.The results of cluster analysis and population structure analysis are generally consistent;that is,the two resource types are closely related and cannot be clustered independently.This study can provide a basis for genetic improvement of rice starch quality.Make full use of the quality genetic diversity of landraces in modern breeding work,further broaden the genetic base of rice and improve rice quality.

Expression of IGF-Ⅱ,p53,p21 and HBxAg in precancerous events of hepatocarcinogenesis induced by AFBI and/or HBV in tree shrews

INTRODUCTIONIn order to study the relationship between oncogeneexpression and HCC generation,we observed theprecancerous hepatic GGT loci,IGF-Ⅱ,p53 andp21 expression during hepatocarcinogenesis of treeshrew induced by hepatitis B virus (HBV) and/oraflatoxin B1 (AFB1).

Gene therapy for human colorectal carcinoma using human CEA promoter controlled bacterial ADP-ribosylating toxin genes:PEA and DTA gene transfer

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Potential roles of tumor suppressor genes and microsatellite instability in hepatocellular carcinogenesis in southern African blacks

MAJOR POINTS OF THE COMMENTED ARTICLECumulative loss of heterozygosity(LOH)ofchromosomal regions and tumor suppressor geneshas been reported in hepatocellular carcinomas(HCCs) from China,Japan,and Korea.In thisissue of the World Journal of Gastroenterology,Martins et al report an analysis of LOH andmicrosatellite instability in HCCs from a group of