Effects of Spinach Powder Fat-Soluble Extract on Proliferation of Human Gastric Adenocarcinoma Cells

Four kinds of assays were used to study the effect of a fat-soluble extract of spinach powder (SPFE) on the proliferation of human gastric adenocareinoma cell line (SGC-7901) in vitro.These studies included: (Ⅰ) cell growth assay, (Ⅱ) colony forming assay, (Ⅲ) MTT colorimetric assay, and (Ⅳ) 3H-TdR incorporation assay. The concentrations of SPFE expressed as the level of β-carotene in the medium were 2×10-8, 2×10-7 and 2×10-6 mol/L β-carotene in assays (Ⅰ)～(Ⅲ), but 4×10- 8, 4×10-7 and 4×10-6 mol/L β-caretene in assay (Ⅳ) respectively. The results indicated that SPFE inhibited the prolifendion and colony forming ability of SGC-7901 cells. And in MTT assay, SPFE inhibited the viability of SGC7901 cells, but no inhibitory effect of SPFE was observed on the viability of lymphocytes in peripheral blood of healthy people. Finally, in the 3H-TdR incorporation test, both SPFE and β-carotene showed significant inhibitory effects on DNA synthesis in SGC-7901 cells, but SPFE was more effective than β-carotene.

CHEMOSENSITIVITY OF MGc80-3 HUMAN GASTRIC ADENOCARCINOMA CELLS AND ITS CLINICAL SIGNIFICANCE

In the present study, the chemosensitivity of MGc80-3 human gastric adenocarcinoma cells was determined by means of colony-forming assay and the in vitro activities of 10 anticancer drugs were examined on the basis of the clinically achievable peak plasma drug concentration. The results showed that MGc80-3 cells were most sensitive to mitomyc'n C, adriamycin and 5-fluorouracil, being consistent with the response noted in clinical gastric cancer. This cell line may retain its original drug sensitivity and may be useful in screening for new compounds with activity against this disease.

CLONING AND IDENTIFICATION OF A GENE RELATED TO THE DIFFERENTIATION OF HUMAN GASTRIC ADENOCARCINOMA CELLS

Objective: To compare the differential expression of mRNA between MKN-28 (highly differentiated) and MKN-45 (poorly differentiated) gastric adenocarcinoma cells and identify genes involved in human gastric adenocarcinoma differentiation. Methods: Differential expression of mRNA between MKN-28 and MKN-45 adenocarcinoma cells was investigated by fluorescent differential display (FDD). Differentially expressed cDNA was analyzed by bioinformatics and confirmed by RT-PCR and Northern-blot. Results: 45 differential fragments were finally attained. One of them (No. 10) was an approximate 750 bp cDNA and highly up-regulated in MKN-45 cells as compared with MKN-28 cells. By using Blastn and UniGene database analysis, we found the fragment was mapped to chromosome 14q11.2–q12 and showed a significant homology to Bcl-2 binding protein gene (BNip3), which was recently identified encoding pro-apoptosis protein located in mitochondrial. Conclusion: The BNip3 induced apoptosis could be suppressed by interacting with bcl-2. The BNip3 gene in tumor cells might be up-regulated by the hypoxia response element through the HIF1a transcription factor, causing death of the hypoxic cells at the center of the tumor where vascularization is usually poor in the process of tumor development.

Inhibitory effects of dobutamine on human gastric adenocarcinoma

AIM: To explore the inhibitory effects of dobutamine on gastric adenocarcinoma cells.

Effects of tachyplesin and n-sodium butyrate on proliferation and gene expression of human gastric adenocarcinoma cell line BGC-823

AIM： To investigate the effects of tachyplesin and n-sodium butyrate on proliferation and gene expression of human gastric adenocarcinoma cell line BGC-823. METHODS： Effects of tachyplesin and n-sodium butyrate on proliferation of BGC-823 cells were determined with trypan blue dye exclusion test and HE staining. Effects of tachyplesin and n-sodium butyrate on cell cycle were detected by flow cytometry. Protein levels of c-erbB-2, c-myc, p53 and p16 were examined by immunocytochemistry. RESULTS： The inhibiting effects were similar after 2.0 mg/L tachyplesin and 2.0 mmol/L n-sodium butyrate treatment, the inhibitory rate of cellular growth was 62.66% and 60.19% respectively, and the respective maximum mitotic index was decreased by 49.35% and 51.69% respectively. Tachyplesin and n-sodium buD/rate treatment could markedly increase the proportion of cells at G0/G1 phase and decrease the proportion at S phase. The expression levels of oncogene c-erbB-2, c-myc, and mtp53 proteins were down-regulated while the expression level of tumor suppressor gene p16 protein was up-regulated after the treatment with tachyplesin or n-sodium buD/rate. The effects of 1.0 mg/L tachyplesin in combination with 1.0 mmol/L n-sodium butyrate were obviously superior to their individual treatment in changing cell cycle distribution and expression of c-erbB-2, c-myc, mtp53 and p16 protein. The inhibitory rate of cellular growth of BGC-823 cells after combination treatment was 62.29% and the maximum mitotic index wasdecreased by 51.95%. CONCLUSION： Tachyplesin as a differentiation inducer of tumor cells has similar effects as n-sodium butyrate on proliferation of tumor cells, expression of correlative oncogene and tumor suppressor gene. It also has a synergistic effect on differentiation of tumor cells.

High mobility group-box 3 overexpression is associated with poor prognosis of resected gastric adenocarcinoma

AIM:To elucidate high mobility group-box 3(HMGB3) protein expression in gastric adenocarcinoma,its potential prognostic relevance,and possible mechanism of action.METHODS:Ninety-two patients with gastric adenocarcinomas surgically removed entered the study.HMGB3 expression was determined by immunohistochemistry through a tissue microarray procedure.The clinicopathologic characteristics of all patients were recorded,and regular follow-up was made for all patients.The inter-relationship of HMGB3 expression with histological and clinical factors was analyzed using nonparametric tests.Survival analysis was carried out by Kaplan-Meier(log-rank) and multivariate Cox(Forward LR) analyses between the group with overexpression of HMGB3 and the group with low or no HMGB3 ex-pression to determine the prognosis value of HMGB3 expression on overall survival.Further,HMGB3 expression was knocked down by small hairpin RNAs(shRNAs) in the human gastric cancer cell line BGC823 to observe its influence on cell biological characteristics.The MTT method was utilized to detect gastric cancer cell proliferation changes,and cell cycle distribution was analyzed by flow cytometry.RESULTS:Among 92 patients with gastric adenocarcinomas surgically removed in this study,high HMGB3 protein expression was detected in the gastric adenocarcinoma tissues vs peritumoral tissues(P < 0.001).Further correlation analysis with patients' clinical and histology variables revealed that HMGB3 overexpression was obviously associated with extensive wall penetration(P = 0.005),a positive nodal status(P = 0.004),and advanced tumor-node-metastasis(TNM) stage(P = 0.001).But there was no correlation between HMGB3 overexpression and the age and gender of the patient,tumor localization or histologic grade.Statistical Kaplan-Meier survival analysis disclosed significant differences in overall survival between the HMGB3 overexpression group and the HMGB3 no or low expression group(P = 0.006).The expected overall survival time was 31.00 ± 3.773 mo(95%CI = 23.605-38.395) for patients with HMGB3 overexpression and 49.074 ± 3.648 mo(95%CI = 41.925-57.311) for patients with HMGB3 no and low-level expression.Additionally,older age(P = 0.040),extensive wall penetration(P = 0.008),positive lymph node metastasis(P = 0.005),and advanced TNM tumor stage(P = 0.007) showed negative correlation with overall survival.Multivariate Cox regression analysis indicated that HMGB3 overexpression was an independent variable with respect to age,gender,histologic grade,extent of wall penetration,lymph nodal metastasis,and TNM stage for patients with resectable gastric adenocarcinomas with poor prognosis(hazard ratio = 2.791,95%CI = 1.233-6.319,P = 0.019).In the gene function study,after HMGB3 was knocked down in the gastric cell line BGC823 by shRNA,the cell proliferation rate was reduced at 24 h,48 h and 72 h.Compared to BGC823 shRNA-negative control(NC) cells,the cell proliferation rate in cells that had HMGB3 shRNA transfected was significantly decreased(P < 0.01).Finally,cell cycle analysis by FACS showed that BGC823 cells that had HMGB3 knocked down were blocked in G1/G0 phase.The percentage of cells in G1/G0 phase in BGC823 cells with shRNA-NC and with shRNA-HMGB3 was 46.84% ± 1.7%,and 73.03% ± 3.51% respectively(P = 0.001),whereas G2/M cells percentage decreased from 26.51% ± 0.83% to 17.8% ± 2.26%.CONCLUSION:HMGB3 is likely to be a useful prognostic marker involved in gastric cancer disease onset and progression by regulating the cell cycle.

Polymorphisms in tumor necrosis factor genes and susceptibility to esophageal squamous cell carcinoma and gastric cardiac adenocarcinoma in a population of high incidence region of North China

Background We investigated the possible association of the functional polymorphisms in the tumor necrosis factor （TNF） genes with susceptibility to esophageal squamous cell carcinoma （ESCC） and gastric cardiac adenocarcinoma （GCA）.Methods The TNF-α-308G/A and TNF-β ＋ 252G/A single nucleotide polymorphisms （SNPs） were genotyped using polymerase-chain reaction-restriction fragment length polymorphism （PCR-RFLP） analysis, in 555 cancer patients （291 ESCC and 264 GCA） and 437 healthy controls in a high incidence region of North China. Results Among healthy controls, frequencies of the TNF-α 1/1, 1/2 and 2/2 genotypes were 89.4% ,9.2% and 1.4% respectively, while frequencies of the TNF-β B1/B1, B1/B2 and B2/B2 genotypes were 12.6% , 32.3% and 55.1%, respectively. No significant difference was found in the overall genotype and allelotype distribution of the TNF-α-308G/A and TNF-β ＋ 252G/A SNPs among cancer patients and controls. However, both the B1/B1 genotype and B1/B2 genotype significantly increased the risk of developing ESCC [ the age and gender adjusted odds ratio （OR） =2.04 and 1.91, 95% confidence interval （CI） = 1.04 -4.43 and 1.14 - 2.60, respectively] and GCA （the age and gender adjusted OR =2. 68 and 2. 64, 95% CI = 1.14 -6.29 and 1.47 -4.72, respectively） in individuals with negative family history of UGIC, in comparison with the B2/B2 genotype. When the two TNF polymorphisms were combined and analyzed, individuals with the TNF-β B1/B2 and TNF-α1/2 or 2/2 genotypes significantly reduced the risk of developing ESCC and GCA, in comparison with those harboring the TNF-β B2/B2 and TNF-α 1/1 genotypes （ the age and gender adjusted OR = 0.37 and 0. 34, 95% CI =0. 15 -0.92 and 0. 13 -0.90, respectively）. Conclusions Therefore, the TNF-α -308G/A and TNF-β ＋ 252G/A genotyping may be used as a stratification markers to predicate the risk of ESCC and GCA development in North China.