Project description:Gastric cancer is one of the most common causes of cancer-related deaths worldwide. The lymph node status represents the strongest prognostic factor. Due to its extremely poor prognosis, the identification of novel therapeutic targets is urgently needed. Therefore, we aimed to assess differentially expressed genes in nodal negative versus nodal positive intestinal type gastric carcinoma by GeneChip array technique. The transcriptional profile of 6 gastric cancers with and without lymphatic dissemination was analyzed. A total of 115 transcripts were found to be up- and 219 to be down-regulated in node positive compared with node negative gastric cancers. Next we searched for differentially expressed GPCRs. We identified 52 GPCRs and GPCR-related genes, which were up- or down-regulated with a fold change factor greater 1.5.
Project description:Carcinogenic bacteria, Helicobacter pylori, induce DNA double-strand breaks in infected host cells, while ATM-dependent DNA damage responses in host cells suppress genome instabilities caused by DNA breakages, which resulting in the suppression of H. pylori-induced gastric cancers. Although Helicobacter pylori infection is etiologically related to the inflammation-related malignancy, gastric cancers, it role in the molecular pathogenesis of disease remains unclear. In vitro studies have suggested the infection may cause breaks in double-stranded DNA. We used microarray analysis of H. pylori-infected human gastric biopsies to investigate the effect of H. pylori on gene expression genes involved in DNA repair and DNA damage response. Micro-array analysis and immunohistochemistory showed that ATM (ataxia-telangiectasia mutated) was upregulated in H. pylori gastritis but down regulated in the premalignant lesion, intestinal metaplasia. Studies in gastric cancer cell lines showed that H. pylori-infection induced activation of ATM and formation of γ-H2AX. γ-H2AX formation was present following infection with bout cag pathogenicity island (PAI)- positive and negative strains but more robust with cag PAI positive strains consistent with the fact that both cag PAI positive negative strains are associated with gastric cancer but the risk is higher with cag PAI positive strains. Eradication of H. pylori infection is associated with a reduction in cancer risk even in the most high risk populations. These data provide a plausible molecular mechanism for a direct bacterial-host interaction increasing cancer risk. To identify tumor suppressors affected by H. pylori-infection, microarray screening was used to compare the gene expression profiles of gastric mucosa obtained from individuals with H. pylori-gastritis and with intestinal metaplasia with tissue from uninfected controls.
Project description:Carcinogenic bacteria, Helicobacter pylori, induce DNA double-strand breaks in infected host cells, while ATM-dependent DNA damage responses in host cells suppress genome instabilities caused by DNA breakages, which resulting in the suppression of H. pylori-induced gastric cancers. Although Helicobacter pylori infection is etiologically related to the inflammation-related malignancy, gastric cancers, it role in the molecular pathogenesis of disease remains unclear. In vitro studies have suggested the infection may cause breaks in double-stranded DNA. We used microarray analysis of H. pylori-infected human gastric biopsies to investigate the effect of H. pylori on gene expression genes involved in DNA repair and DNA damage response. Micro-array analysis and immunohistochemistory showed that ATM (ataxia-telangiectasia mutated) was upregulated in H. pylori gastritis but down regulated in the premalignant lesion, intestinal metaplasia. Studies in gastric cancer cell lines showed that H. pylori-infection induced activation of ATM and formation of γ-H2AX. γ-H2AX formation was present following infection with bout cag pathogenicity island (PAI)- positive and negative strains but more robust with cag PAI positive strains consistent with the fact that both cag PAI positive negative strains are associated with gastric cancer but the risk is higher with cag PAI positive strains. Eradication of H. pylori infection is associated with a reduction in cancer risk even in the most high risk populations. These data provide a plausible molecular mechanism for a direct bacterial-host interaction increasing cancer risk. To identify tumor suppressors affected by H. pylori-infection, microarray screening was used to compare the gene expression profiles of gastric mucosa obtained from individuals with H. pylori-gastritis and with intestinal metaplasia with tissue from uninfected controls.
Project description:Purpose: To improve clinical outcome of gastric cancer patients, most emphasis is on improving therapeutic regimens, including more extensive surgery as well as (neo)adjuvant chemotherapy. The present study set out to identify, based on DNA copy number profiling, subgroups of patients with different clinical outcomes who thus would qualify for different therapy intensities. Experimental Design: DNA of 206 gastric cancer patients was isolated and analyzed by genome wide array comparative genomic hybridization. DNA copy number profiles were evaluated and correlated to lymph node status and survival. In addition, HSP90 protein expression was analyzed and correlated to survival in 290 gastric cancer patients. Results: Frequent (>20%) DNA copy number gains were observed on chromosomes 1p, 6p, 7p, 7q, 8q, 11q, 12q, 13q, 16p, 16q, 17q, 19p, 19q, 20p, 20q, 21q and 22q, and losses on chromosomes 4p, 4q, 6p, 6q, 9p, 13q and 21q. Lymph node negative gastric cancers showed significantly more losses on chromosomes 5q11.2-q35.1, 10q11.23-21.3 and 14q32.11-q32.33. In addition, losses on 5q11.2-q31.3 and 14q32.11-q32.33 were highly correlated to good clinical outcome, in both lymph node negative and positive gastric cancer patients. Loss of expression of HSP90, located on chromosome 14q32.2, correlated to good survival time. Conclusion: Genome wide DNA copy number profiling allows to identify a subgroup of gastric cancers, marked by losses on chromosomes 5q11.2-q31.3 and 14q32.11-q32.33 that have an excellent clinical outcome after surgery alone, and patients with these tumors are unlikely to benefit from additional intensified therapies. Possible biological mechanisms could involve loss of heat shock proteins, of which the coding genes are located at these chromosomal regions. 183 gastric adenocarcinomas
Project description:In this study, we investigated CNAs of 59 tumor samples from 27 patients with submucosal-invasive gastric cancers (SMGC) by 44k oligonucleotide-based array comparative genomic hybridization (array CGH). 23 mucosal portion of SMGC vs 23 paired submucosal (SM) portion of SMGC, 9 SM portion vs 9 paired lymph node (LN) metastasis, 12 SMGC with LN metastasis vs 15 SMGC without LN metastasis
Project description:Carcinogenic bacteria, Helicobacter pylori, induce DNA double-strand breaks in infected host cells, while ATM-dependent DNA damage responses in host cells suppress genome instabilities caused by DNA breakages, which resulting in the suppression of H. pylori-induced gastric cancers. Although Helicobacter pylori infection is etiologically related to the inflammation-related malignancy, gastric cancers, it role in the molecular pathogenesis of disease remains unclear. In vitro studies have suggested the infection may cause breaks in double-stranded DNA. We used microarray analysis of H. pylori-infected human gastric biopsies to investigate the effect of H. pylori on gene expression genes involved in DNA repair and DNA damage response. Micro-array analysis and immunohistochemistory showed that ATM (ataxia-telangiectasia mutated) was upregulated in H. pylori gastritis but down regulated in the premalignant lesion, intestinal metaplasia. Studies in gastric cancer cell lines showed that H. pylori-infection induced activation of ATM and formation of γ-H2AX. γ-H2AX formation was present following infection with bout cag pathogenicity island (PAI)- positive and negative strains but more robust with cag PAI positive strains consistent with the fact that both cag PAI positive negative strains are associated with gastric cancer but the risk is higher with cag PAI positive strains. Eradication of H. pylori infection is associated with a reduction in cancer risk even in the most high risk populations. These data provide a plausible molecular mechanism for a direct bacterial-host interaction increasing cancer risk.
Project description:We used microarrays to identify the gene expression accompanied with growth arrest caused by the transduction of CDX1 or CDX2. Ectopic expression of CDXs causes intestinal metaplasia, which is thought to be precancerous legion of gastric cancer. On the contrary, there were some studies reported that CDX2 positive gastric cancers showed better prognosis or tumor suppressive activity. To evaluate the effect of exogenous CDX expression in gastric cancer cells, we transducted CDX1 or CDX2 in two CDX negative expression cell lines, MKN7 and TMK1.
Project description:Purpose: To improve clinical outcome of gastric cancer patients, most emphasis is on improving therapeutic regimens, including more extensive surgery as well as (neo)adjuvant chemotherapy. The present study set out to identify, based on DNA copy number profiling, subgroups of patients with different clinical outcomes who thus would qualify for different therapy intensities. Experimental Design: DNA of 206 gastric cancer patients was isolated and analyzed by genome wide array comparative genomic hybridization. DNA copy number profiles were evaluated and correlated to lymph node status and survival. In addition, HSP90 protein expression was analyzed and correlated to survival in 290 gastric cancer patients. Results: Frequent (>20%) DNA copy number gains were observed on chromosomes 1p, 6p, 7p, 7q, 8q, 11q, 12q, 13q, 16p, 16q, 17q, 19p, 19q, 20p, 20q, 21q and 22q, and losses on chromosomes 4p, 4q, 6p, 6q, 9p, 13q and 21q. Lymph node negative gastric cancers showed significantly more losses on chromosomes 5q11.2-q35.1, 10q11.23-21.3 and 14q32.11-q32.33. In addition, losses on 5q11.2-q31.3 and 14q32.11-q32.33 were highly correlated to good clinical outcome, in both lymph node negative and positive gastric cancer patients. Loss of expression of HSP90, located on chromosome 14q32.2, correlated to good survival time. Conclusion: Genome wide DNA copy number profiling allows to identify a subgroup of gastric cancers, marked by losses on chromosomes 5q11.2-q31.3 and 14q32.11-q32.33 that have an excellent clinical outcome after surgery alone, and patients with these tumors are unlikely to benefit from additional intensified therapies. Possible biological mechanisms could involve loss of heat shock proteins, of which the coding genes are located at these chromosomal regions.
Project description:The study was undertaken to identify microRNAs differently expressed by intestinal type of gastric cancer using miRNA microarray. The miRNA expression in the intestinal type of gastric cancer depending on H. pylori infection suggest that different gastric cancer pathogenesis could be exist between H. pylori-positive and -negative gastric cancer. Total RNA was extracted from cancerous region and non-cancerous regions in formalin fixed paraffin embedded tissues of intestinal type gastric cancer patients who were H. pylori-positive (n=8) or -negative (n=8). Corresponding author: Nayoung Kim, M.D., Department of Internal Medicine, Seoul National University Bundang Hospital (Tel., +82-31-787-7008; e-mail, nayoungkim49@empas.com).
Project description:Carcinogenic bacteria, Helicobacter pylori, induce DNA double-strand breaks in infected host cells. Therefore, we have investigated which genes are upregulated after the infection. Although Helicobacter pylori infection is etiologically related to the inflammation-related malignancy, gastric cancers, it role in the molecular pathogenesis of disease remains unclear. In vitro studies have suggested the infection may cause breaks in double-stranded DNA. We used microarray analysis of H. pylori-infected human gastric biopsies to investigate the effect of H. pylori on gene expression genes involved in DNA repair and DNA damage response. Micro-array analysis and immunohistochemistory showed that ATM (ataxia-telangiectasia mutated) was upregulated in H. pylori gastritis but down regulated in the premalignant lesion, intestinal metaplasia. Studies in gastric cancer cell lines showed that H. pylori-infection induced activation of ATM and formation of ?-H2AX. ?-H2AX formation was present following infection with bout cag pathogenicity island (PAI)- positive and negative strains but more robust with cag PAI positive strains consistent with the fact that both cag PAI positive negative strains are associated with gastric cancer but the risk is higher with cag PAI positive strains. Eradication of H. pylori infection is associated with a reduction in cancer risk even in the most high risk populations. These data provide a plausible molecular mechanism for a direct bacterial-host interaction increasing cancer risk. To identify tumor suppressors affected by H. pylori-infection, microarray screening was used to compare the gene expression profiles of AGS cells, a gastric cancer cell line, infected with various mutants of H. pylori.