AIM：To evaluate the diagnostic role of serum RASSF1A promoter hypermethylation in gastric and colorectal adenocarcinoma. METHODS：Methylation-specific polymerase chain reaction （MSPCR） was used to examine the promo...AIM：To evaluate the diagnostic role of serum RASSF1A promoter hypermethylation in gastric and colorectal adenocarcinoma. METHODS：Methylation-specific polymerase chain reaction （MSPCR） was used to examine the promoter methylation status of the serum RASSF1A gene in 47 gastric adenocarcinoma patients, 45 colorectal adenocarcinoma patients, 60 patients with benign gastrointestinal disease （30 with benign gastric disease and 30 with benign colorectal disease）, and 30 healthy donor controls. Apaired study of RASSF1A promoter methylation status in primary tumor, adjacent normal tissue, and postopertive serum were conducted in 25 gastric and colorectal adenocarcinoma patients who later were underwent surgical therapy. RESULTS：The frequencies of detection of serum RASSF1A promoter hypermethylation in gastric （34.0%） and colorectal （28.9%） adenocarcinoma patients were significantly higher than those in patients with benign gastric （3.3%） or colorectal （6.7%） disease or in healthy donors （0%） （P 〈 0.01）. The methylation status of RASSF1A promoter in serum samples was consistent with that in paired primary tumors, and the MSPCR results for RASSF1A promoter methylation status in paired preoperative samples were consistent with those in postoperative serum samples. The serum RASSF1A promoter hypermethylation did not correlate with patient sex, age, tumor differentiation grade, surgical therapy, or serum carcinoembryonic antigen level. Although the serum RASSF1A promoter hypermethylation frequency tended to be higher in patients with distant metastases, there was no correlation between methylation status and metastasis. CONCLUSION：Aberrant CpG island methylation within the promoter region of RASSF1A is a promising biomarker for gastric and colorectal cancer.展开更多
AIM： To investigate the changes of methylation state and expression of RASSF1A gene in human gastric cancer cell lines SGC7901 and BGC823 which were treated in vitro with demethlylating agent 5-Aza-CdR in combination...AIM： To investigate the changes of methylation state and expression of RASSF1A gene in human gastric cancer cell lines SGC7901 and BGC823 which were treated in vitro with demethlylating agent 5-Aza-CdR in combination with histone deacetylase inhibitor NaB. METHODS： After SGC7901 and BGC823 cells were treated with 5-Aza-CdR and/or NaB, the methylation state of RASSFIA gene was detected by methylationspecific PCR, and the changes in expression of mRNA and protein level of RASSFIA gene were observed by RT-PCR and Western-blotting before and after drug treatment. RESULTS： Hypermethylation was detected in the promoter region of RASSF1A gene in both SGC7901 and BGC823 cells, and there was no expression of this gene at both mRNA and protein level. After treatment with 5-Aza-CdR, demethylation occurred in the promoter region of RASSFIA gene, which subsequently induced re-expression of this gene. The treatment with NaB alone showed no effect on the methylation state and expression of RASSFIA gene. The combined treatment of 5-Aza-CdR and NaB induced complete demethylation of RASSFIA gene, leading to a significantly higher reexpression of the mRNA and protein of RASSFIA than those treated with 5-Aza-CdR alone （P 〈 0.05）. CONCLUSION： Hypermethylation in the promoter region is related to inactivation of RASSFIA gene in human gastric cancer cell lines SGC7901 and BGC823, while demethlylating agent 5-Aza-CdR can reverse the methylation state of RASSF1A gene and induce itsre-expression. Histone deacetylase inhibitor NaB had a synergistic effect with 5-Aza-CdR in both demethylation and gene transcriptional regulation.展开更多
AIM:To investigate the role of Ras association domain family protein 1 isoform A (RASSF1A) in gastric tumorigenesis. METHODS:Through over-expression of RASSF1A gene in the SGC7901 cell line which was induced by a lipo...AIM:To investigate the role of Ras association domain family protein 1 isoform A (RASSF1A) in gastric tumorigenesis. METHODS:Through over-expression of RASSF1A gene in the SGC7901 cell line which was induced by a lipofectamine-mediated gene transfer approach. Activator protein-1 (AP-1) DNA binding activity was measured by electrophoretic mobility shift assay (EMSA). RESULTS:Compared with the control clones, cells over- expressing RASSF1A exhibited significant inhibition of cell growth with G1 cell cycle arrest in vitro and in vivo. The over-expression of RASSF1A significantly inhibited AP-1 activity in SGC7901 cells (0.981±0.011 vs 0.354±0.053, P<0.001). In addition, both Western blot analysis and immunocytochemistry demonstrated that RASSF1A down-regulated the expression of c-Fos (0.975± 0.02 vs 0.095±0.024, P<0.001) but not c-Jun. CONCLUSION: Over-expression of RASSF1A inhibits the growth of SGC7901 cells by negatively regulating the AP-1 activity, the latter in turn negatively signals cell proliferation.展开更多
Aberrant tumor suppressor gene promoter methylation was associated with the several cancers, including breast cancer, which was the common female deaths in most countries involved in Vietnam. The methylation in tumor ...Aberrant tumor suppressor gene promoter methylation was associated with the several cancers, including breast cancer, which was the common female deaths in most countries involved in Vietnam. The methylation in tumor suppressor genes, including RASSFIA, were the key targets of establishing the potential biomarkers for prognosis and early diagnosis of breast cancer. In present study, with the aim towards using the hypermethylation at CpG islands of promoter of RASSFIA as the biomarker for breast cancer in Vietnamese population, MSP （methyl specific PCR） was carried out to analyze the hypermethylation status ofRASSFIA gene in 115 samples including 95 breast cancer specimens and 20 normal breast tissues from another disease （not breast cancer）. All samples were obtained from Ho Chi Minh City Medical Hospital, Vietnam. The known predictive and prognostic factors： HER2/neu overexpression was immunohistochemistry stained as input value for breast cancer specimens. For input value confirmed, the overexpression of p53 protein was also analyzed together with prior immunochemical assay. The results indicated that the hypermethylation of frequencies for methylation of given gene reached 42.1% （P 〈 0.05）. In addition, the DNA hypermethylation of RASSFIA gene increased the possibility to be breast cancer with high incidence via calculated of odd ratio （P 〈 0.05）. In conclusion, the hypermethylation of candidate genes could be used as the promising biomarkers applying in Vietnamese breast cancer patients.展开更多
文摘AIM：To evaluate the diagnostic role of serum RASSF1A promoter hypermethylation in gastric and colorectal adenocarcinoma. METHODS：Methylation-specific polymerase chain reaction （MSPCR） was used to examine the promoter methylation status of the serum RASSF1A gene in 47 gastric adenocarcinoma patients, 45 colorectal adenocarcinoma patients, 60 patients with benign gastrointestinal disease （30 with benign gastric disease and 30 with benign colorectal disease）, and 30 healthy donor controls. Apaired study of RASSF1A promoter methylation status in primary tumor, adjacent normal tissue, and postopertive serum were conducted in 25 gastric and colorectal adenocarcinoma patients who later were underwent surgical therapy. RESULTS：The frequencies of detection of serum RASSF1A promoter hypermethylation in gastric （34.0%） and colorectal （28.9%） adenocarcinoma patients were significantly higher than those in patients with benign gastric （3.3%） or colorectal （6.7%） disease or in healthy donors （0%） （P 〈 0.01）. The methylation status of RASSF1A promoter in serum samples was consistent with that in paired primary tumors, and the MSPCR results for RASSF1A promoter methylation status in paired preoperative samples were consistent with those in postoperative serum samples. The serum RASSF1A promoter hypermethylation did not correlate with patient sex, age, tumor differentiation grade, surgical therapy, or serum carcinoembryonic antigen level. Although the serum RASSF1A promoter hypermethylation frequency tended to be higher in patients with distant metastases, there was no correlation between methylation status and metastasis. CONCLUSION：Aberrant CpG island methylation within the promoter region of RASSF1A is a promising biomarker for gastric and colorectal cancer.
基金The National Natural Science Foundation of China, No. 30572162, No. 30271477The Special Scientific Research Fundation for Doctors, State Education Ministry,No.20050159001
文摘AIM： To investigate the changes of methylation state and expression of RASSF1A gene in human gastric cancer cell lines SGC7901 and BGC823 which were treated in vitro with demethlylating agent 5-Aza-CdR in combination with histone deacetylase inhibitor NaB. METHODS： After SGC7901 and BGC823 cells were treated with 5-Aza-CdR and/or NaB, the methylation state of RASSFIA gene was detected by methylationspecific PCR, and the changes in expression of mRNA and protein level of RASSFIA gene were observed by RT-PCR and Western-blotting before and after drug treatment. RESULTS： Hypermethylation was detected in the promoter region of RASSF1A gene in both SGC7901 and BGC823 cells, and there was no expression of this gene at both mRNA and protein level. After treatment with 5-Aza-CdR, demethylation occurred in the promoter region of RASSFIA gene, which subsequently induced re-expression of this gene. The treatment with NaB alone showed no effect on the methylation state and expression of RASSFIA gene. The combined treatment of 5-Aza-CdR and NaB induced complete demethylation of RASSFIA gene, leading to a significantly higher reexpression of the mRNA and protein of RASSFIA than those treated with 5-Aza-CdR alone （P 〈 0.05）. CONCLUSION： Hypermethylation in the promoter region is related to inactivation of RASSFIA gene in human gastric cancer cell lines SGC7901 and BGC823, while demethlylating agent 5-Aza-CdR can reverse the methylation state of RASSF1A gene and induce itsre-expression. Histone deacetylase inhibitor NaB had a synergistic effect with 5-Aza-CdR in both demethylation and gene transcriptional regulation.
文摘AIM:To investigate the role of Ras association domain family protein 1 isoform A (RASSF1A) in gastric tumorigenesis. METHODS:Through over-expression of RASSF1A gene in the SGC7901 cell line which was induced by a lipofectamine-mediated gene transfer approach. Activator protein-1 (AP-1) DNA binding activity was measured by electrophoretic mobility shift assay (EMSA). RESULTS:Compared with the control clones, cells over- expressing RASSF1A exhibited significant inhibition of cell growth with G1 cell cycle arrest in vitro and in vivo. The over-expression of RASSF1A significantly inhibited AP-1 activity in SGC7901 cells (0.981±0.011 vs 0.354±0.053, P<0.001). In addition, both Western blot analysis and immunocytochemistry demonstrated that RASSF1A down-regulated the expression of c-Fos (0.975± 0.02 vs 0.095±0.024, P<0.001) but not c-Jun. CONCLUSION: Over-expression of RASSF1A inhibits the growth of SGC7901 cells by negatively regulating the AP-1 activity, the latter in turn negatively signals cell proliferation.
文摘Aberrant tumor suppressor gene promoter methylation was associated with the several cancers, including breast cancer, which was the common female deaths in most countries involved in Vietnam. The methylation in tumor suppressor genes, including RASSFIA, were the key targets of establishing the potential biomarkers for prognosis and early diagnosis of breast cancer. In present study, with the aim towards using the hypermethylation at CpG islands of promoter of RASSFIA as the biomarker for breast cancer in Vietnamese population, MSP （methyl specific PCR） was carried out to analyze the hypermethylation status ofRASSFIA gene in 115 samples including 95 breast cancer specimens and 20 normal breast tissues from another disease （not breast cancer）. All samples were obtained from Ho Chi Minh City Medical Hospital, Vietnam. The known predictive and prognostic factors： HER2/neu overexpression was immunohistochemistry stained as input value for breast cancer specimens. For input value confirmed, the overexpression of p53 protein was also analyzed together with prior immunochemical assay. The results indicated that the hypermethylation of frequencies for methylation of given gene reached 42.1% （P 〈 0.05）. In addition, the DNA hypermethylation of RASSFIA gene increased the possibility to be breast cancer with high incidence via calculated of odd ratio （P 〈 0.05）. In conclusion, the hypermethylation of candidate genes could be used as the promising biomarkers applying in Vietnamese breast cancer patients.
