Effects of NANOG/deleted in breast cancer 1 pathway on biological behavior of gastric cancer cells / 中华消化杂志

Objective To investigate the effects of NANOG/deleted in breast cancer 1 (DBC1)pathway on biological behavior of gastric cancer cells.Methods From May 2014 to May 2015,25 patients who underwent gastric cancer resection were selected.The expression of NANOG and DBC1 was detected by real time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting in N-tera,SGC-7901,HGC-27,MKN-45,MGC803,NCI-N87,BGC823 cell lines,normal gastric epithelial cell line GES-1 and gastric cancer tissues.The proliferation,apoptosis and colony formation ability of MKN-45 cells in short hairpin (sh)NANOG-1,shNANOG-2,sh-control and shDBC1 groups were determined by MTT assay,flow cytometry and colony forming assay.The effects on the expression of the two genes in MKN-45 cells were verified by polymerase chain reaction (PCR) in shNANOG,sh-control,shDBC1 and shDBC1+NANOG groups and the effects of down regulation of DBC1 on cell biological behavior were further investigated.The differences in gene expression profile after interference which were screened by gene chips and bioinformatics were analyzed.The mechanism of NANOG regulating DBC1 was explored by Dual-luciferase assay.T test was used for two groups comparison while one-way analysis of variance was for multiple groups.Results NANOG and NANOG mRNA were highly expressed in N-tera cells,which were 1.02±0.08 and 0.95 ±0.03,respectively,and the expressions in SGC-7901,HGC-27,MKN-45 and NCI-N87 cell lines were 0.67±0.03 and 0.64±0.04,0.58±0.02 and 0.28±0.02,0.83±0.03 and 1.04 ± 0.05,and 0.61 ± 0.02 and 0.64 ± 0.08,respectively;no expression was detected in normal gastric epithelial cell line GES-1,and the expressions in MKN-45 cells were the highest in gastric cancer cells (F=21.51 and 85.53,both P＜0.01).The expression of DBC1 in HGC-27,MGC803,NCIN87,SGC-7901,BGC823 and MKN-45 cells were 0.37±0.02,0.33±0.02,0.42±0.01,0.58±0.04,0.33±0.05,and 0.87±0.02,respectively;while there was no expression of NANOG,NANOG mRNA and DBC1 in GES-1 cells.The expression of NANOG mRNA and DBC1 was detected in gastric cancer tissues of 24.0％ (6/25) patients.Compared with that of the sh control group,the apoptosis rates of MKN-45 cells in the shNANOG-1,shNANOG-2 groups were increased ((2.24±0.17)％ vs (6.03±0.24) ％ and (6.95 ± 0.38) ％),and the difference was statistically significant (F =81.18,P ＜ 0.01).Compared with that of the sh-eontrol group,the colony forming abilities of MKN-45 cells in the shNANOG-1 and shNANOG-2 groups were significantly decreased (172.03±6.35 vs 74.32±5.32 and 53.08±3.82),and the difference was statistically significant(F=171.61,P＜0.01).The results of PCR showed that compared with that of sh-eontrol group,the expression levels of NANOG mRNA and DBC1 mRNA in shNANOG group were lower (1.04±0.05 vs 0.54±0.03,1.08±0.08 vs 0.42±0.03),the level of DBC1 mRNA in shDBC1 group was lower (1.08±0.08 vs 0.50±0.04),and the differences were statistically significant (t=9.15,7.37 and 6.06,all P＜0.01).The expression level of NANOG mRNA in shDBC1 + NANOG group was higher (1.04 ± 0.05 vs 3.01 ± 0.08),while the expression level of DBC1 mRNA was lower (1.08 ± 0.08 vs 0.71 ± 0.06),and the difference was statistically significant (t=-20.22 and 3.74,both P＜0.05).The expression level of DBC1 mRNA in shDBC1±NANOG group was higher than that in shDBC1 group (0.71±0.06 vs 0.50±0.04),and the difference was statistically significant (t=4.00,P＜0.05).Bioinformatic analysis showed that DBC1 gene promoter region had the potential NANOG protein binding sites.Dual-luciferase assay indicated NANOG played the role in transcription activation in DBC1 promoter regions.Conclusion NANOG and DBC1 are highly expressed in various gastric cancer cell lines.NANOG may affect the proliferation,apoptosis and colony formation of MKN-45 cells by regulating the expression of DBC1.NANOG/DBC1 pathway may be a promising new target of gastric cancer treatment.

Analysis ofDBC1 gene promoter methylation in cervical cancer tissues of Uyghur women in Xinjiang / 中国癌症杂志

Background and purpose:In recent years, epigenetics research has become a new direction of cancer research. A large number of results have shown that the abnormal changes of epigenetic modifications have close connection with cancer. Genome-wide epigenetic modifications have become new markers for cancer. This study aimed to investigate the methylation of the promoter ofDBC1 gene in cervical cancer tissues of Uyghur women in Xinjiang, to explore the correlation between the gene methylation and the infection of HPV, and to evaluate whether it can be used as a tool with high sensitivity and specificity for cervical cancer screening.Methods:This study detected the infection of HPV16, 18 in 43 normal cervical tissues, 35 cervical intraepithelial neoplasia tissues and 54 cervical cancer tissues using the polymerase chain reaction (PCR) method. The methylation of the promoter ofDBC1 gene in above-mentioned tissues was detected by the methylation-specific PCR method. The expression ofDBC1 at mRNA level was measured by real-time fluorescent quantitative polymerase chain reaction (RTFQ-PCR) in 10 methylation-negative normal cervical tissues and 10 methylation-positive cervical cancer tissues.Results:In normal cervical tissues, CIN tissues and cervical cancer tissues, the infection ratios of HPV16 were 18.6%, 34.3% and 68.5%, respectively; the infection ratios of HPV18 were 2.3%, 8.6% and 16.7%, respectively; and the methylation ratios ofDBC1 gene were 23.3%, 40.0%, 87.0%, respectively. In 79 high-grade squamous intraepithelial lesions (CINⅡ and Ⅲ) and cervical cancer tissues, 50 of 79 were infected with HPV16/18, while 29 of 79 were negative. The methylation ratio ofDBC1 gene was 88.0% in HPV16/18 infection positive group while the methylation ratio was 55.2% in negative group (P<0.05). The expression ofDBC1 gene at mRNA level in 10 methy- lation-positive cervical cancer tissues was significantly lower than that in the 10 methylation-negative normal cervical tissues (P<0.05).Conclusion:The methylation ofDBC1 gene may become a molecular marker to detect cervical cancer of Uyghur women in Xinjiang.DBC1 gene methylation combined with HPV16/18 infection test can be used to aid diagnosis of cervical cancer.

Decreased DBC1 Expression Is Associated With Poor Prognosis in Patients With Non-Muscle-Invasive Bladder Cancer

PURPOSE: The deleted in bladder cancer 1 (DBC1) gene is located within chromosome 9 (9q32-33), a chromosomal region that frequently shows loss of heterozygosity in bladder cancer (BC). It is suspected that it acts as a tumor suppressor gene, but its prognostic value remains unclear. The aim of the present study was to investigate the value of DBC1 as a prognostic marker in BC. MATERIALS AND METHODS: The expression of DBC1 was determined by real-time polymerase chain reaction analysis in 344 patients with BC (220 non-muscle-invasive BC [NMIBC] and 124 muscle-invasive BC [MIBC]) and in 34 patients with normal bladder mucosa. The results were compared with clinicopathologic parameters, and the prognostic value of DBC1 was evaluated by Kaplan-Meier analysis and a multivariate Cox regression model. RESULTS: DBC1 expression was significantly decreased in patients with MIBC compared with those diagnosed with NMIBC (p=0.010). Patients with aggressive tumor characteristics had lower DBC1 expression levels in NMIBC (each, p<0.05). By multivariate Cox regression analysis, low DBC1 expression was a predictor of progression to MIBC (hazard ratio, 7.104; p=0.013). Kaplan-Meier estimates revealed a significant difference in tumor recurrence, progression to MIBC, and cancer-specific survival depending on the level of DBC1 expression in NMIBC (log-rank test, each, p<0.05). CONCLUSIONS: The expression of DBC1 was associated with tumor aggressiveness, progression to MIBC, and survival in NMIBC. Our results suggest that DBC1 expression can be a useful prognostic marker for patients with NMIBC.

SIRT1 Expression Is Associated with Good Prognosis in Colorectal Cancer

BACKGROUND: Silent mating type information regulation 2 homolog 1 (SIRT1), an NAD+-dependent deacetylase, might act as a tumor promoter by inhibiting p53, but may also as a tumor suppressor by inhibiting several oncogenes such as beta-catenin and survivin. Deleted in breast cancer 1 (DBC1) is known as a negative regulator of SIRT1. METHODS: Immunohistochemical expressions of SIRT1, DBC1, beta-catenin, surviving, and p53 were evaluated using 2 mm tumor cores from 349 colorectal cancer patients for tissue microarray. RESULTS: Overexpression of SIRT1, DBC1, survivin, and p53 was seen in 235 (67%), 183 (52%), 193 (55%), and 190 (54%) patients, respectively. Altered expression of beta-catenin was identified in 246 (70%) patients. On univariate analysis, overexpression of SIRT1 (p=0.029) and altered expression of beta-catenin (p=0.008) were significantly associated with longer overall survival. Expression of SIRT1 was significantly related to DBC1 (p=0.001), beta-catenin (p=0.001), and survivin (p=0.002), but not with p53. On multivariate analysis, age, tumor stage, differentiation, and expression of SIRT1 were independent prognostic factors significantly associated with overall survival. CONCLUSIONS: SIRT1 overexpression is a good prognostic factor for colorectal cancer, and SIRT1 may interact with beta-catenin and survivin rather than p53.

Expression of SIRT1 and DBC1 in Gastric Adenocarcinoma

BACKGROUND: Sirtuin 1 (SIRT1) and deleted in breast cancer 1 (DBC1) are known as tumor suppressor or promoter genes. This may be due to their diverse functions and interaction with other proteins. Gastric adenocarcinoma is one of the most common malignancies, but little is known about its carcinogenesis. Therefore, we investigated the association of immunohistochemical expression of SIRT1, DBC1, p53, and beta-catenin and their variable clinicopathological characteristics. METHODS: We obtained samples from 452 patients who underwent gastrectomy. Tissue microarray blocks were constructed and immonohistochemical staining was performed. RESULTS: Expression of DBC1 and SIRT1 was associated with lower histologic grade, intestinal type of Lauren classification, and lower pT (p<0.001) and pN stage (DBC1, p=0.002; SIRT1, p<0.001). Association between absence of lymphatic invasion, and SIRT1 (p=0.001) and DBC1 (p=0.004) was observed. Cytoplasmic beta-catenin expression was associated with lower histologic grade, pT, pN, tumor-node-metastasis (TNM) stage, DBC1 (p<0.001), and SIRT1 (p=0.001). Expression of SIRT1 and DBC1 was not associated with p53 (p=0.063 and p=0.060). DBC1 was an independent good prognostic factor in multivariate analysis (p=0.012). CONCLUSIONS: SIRC1 and DBC1 can be considered to be good prognostic factors in gastric adenocarcinoma.