Function of apoptosis and expression of the proteins Bcl-2, p53 and C-myc in the development of gastric cancer

Hsa_circ_0000231 Accelerates Cell Autophagy and Promotes Cell Proliferation and Invasion of Colorectal Cancer via miR-140-3p/Bcl-2 Axis

Accumulating evidence indicated that circular RNAs (circRNAs) directly sponge to microRNAs (miRNAs),(miRNAs), which in turn regulate the gene expression and affect the malignancy behavior at the posttranscriptional level. However, the expression levels, function, and mechanism of circ_0000231 in colorectal cancer (CRC) are largely unknown. The expression levels of circ_0000231, miR-140-3p, and Bcl-2 in 110 CRC tissues and matched normal colorectal tissues were detected by qRT-PCR method. circ_0000231 and Bcl-2 were suppressed by siRNA, and miR-140-3p was overexpressed by RNA mimics in CRC cell lines. The function-based experiments were conducted to detect the proliferation and migratory abilities in CRC cell lines. RNA pull-down, RNA immunoprecipitation (RIP), and dual-fluorescence reporter assay were conducted to verify the association among circ_0000231, miR-140-3p, and Bcl-2. Western blot analysis and mRFP-GFP-LC3 adenovirus were used to detect the autophagy level affected by circ_0000231, miR-140-3p, and Bcl-2 axis. Downregulated circ_0000231 significantly suppressed the proliferation and migratory abilities of CRC cells by suppressing autophagy and promoting G0/G1 phase arrest. Furthermore, RNA pull-down, RIP, and dual-fluorescence reporter assays confirmed that circ_0000231 regulates the expression of Bcl-2 by directly targeting miR-140-3p. More importantly, circ_0000231 promoted the levels of autophagy via the miR-140-3p/Bcl-2 axis in CRC. Our study demonstrated that circ_0000231, as a tumor promotor, enhances the level of autophagy by regulating Bcl-2 via targeting miR-140-3p. Moreover, circ_0000231 might serve as a diagnostic and prognostic indicator and a novel molecular target for CRC therapy.

Gastroprotective effect of rhodanine and 2,4-thiazolidinediones scaffolds in rat stomachs by contribution of anti-apoptotic (BCL-2) and tumor suppressor (P53) proteins

In recent times, the methods used to evaluate gastric ulcer healing worldwide have been based on visual examinations and estimating ulcer dimensions in experimental animals. In this study, the protective effect of rhodanine and 2,4-thiazolidinediones scaffolds compared to esomeprazole was investigated in an ethanol model of stomach ulcers in rats. Pretreatment with experimental treatments or esomeprazole prevented the development of ethanol-induced gastric ulcers. The severity of the lesions and injuries was significantly lower than that of vehicle (10% Tween 80) treated rats. Significant and excellent results were obtained with the compound 6 group, with inhibition percentage and ulcer area values of 97.8% and 12.8 ± 1.1 mm2, respectively. Synthesized compounds 2, 7 and 8 exhibited inhibition percentages and ulcer areas of 94.3% and 31.2 ± 1.1 mm2, 91. 3% and 48.1 ± 0. 8 mm2, 89. 5% and 57. 6 ± 1. 2 mm2, and 89. 1% and 60.3 ± 0. 8 mm2, respectively. These biological outcomes are consistent with the docking studies in which Compounds 7 and 8 showed remarkable binding site affinities toward human H+/K+-ATPase α protein (ID: P20648), rat H+/K+-ATPase α protein (ID: P09626), and Na+/K+-ATPase crystal structure (PDB ID:2ZXE) with binding site energies of - 10.7, - 9.0, and - 10.4 (kcal/mol) and - 8.7, - 8.5, and - 8.0 (kcal/mol), respectively. These results indicate that these test samples were as effective as esomeprazole. Likewise, immunohistochemical staining of antiapoptotic (BCL2) and tumor suppressor (P53) proteins showed strong positive marks in the10% Tween 80- treated group, opposing the mild staining results for the esomeprazole-treated group. Similarly, the staining intensity of the group treated with Compounds 2-8 was variable for both proteins.

Upregulation of XRCC1 DNA Repair Gene, Interleukin-8, and Bcl-2 Antiapoptotic Gene Levels in Kurdish Patients with Gastric Adenocarcinoma

Gastric cancer (GC) is one of the deadliest tumors due to its competence to invade and metastasize. The DNA repair gene (XRCC1), interleukin-8 (IL-8) gene, and B-cell lymphoma 2 (Bcl-2) gene play a crucial role in the development and progression of GC. This study aimed to evaluate the expression of these target genes in GC patients in the Kurdistan region of Iraq. Gastric cancer tissues were collected from 29 patients diagnosed with gastric adenocarcinoma that underwent gastric resection, and 21 tissue samples were obtained from healthy patients that underwent gastroscopy. The gastric tissues were collected in different hospitals in Erbil and Sulaymaniyah cities in the Kurdistan region of Iraq. Moreover, the data regarding Helicobacter pylori, age, gender, and stage of the disease were recorded and analyzed using GraphPad Prism. The gene expression levels of XRCC1, IL-8, and Bcl-2 from gastric tissue were studied by real-time quantitative polymerase chain reaction. The results showed that H. pylori infection was equally distributed among males and females in the tissues of gastric patients, while most of the H. pylori-negative patients were females. It is also found that gastric patients aged 30-60 years old are more commonly tested for the H. pylori test. Accordingly, in this study, patients diagnosed with gastric inflammation more often tested positive for H. pylori, while patients diagnosed with gastric cancer tested negative for this infection. Additionally, it was found that the target genes (XRCC1, IL-8, and Bcl-2) were significantly upregulated in GC patients, compared to the healthy group. Finally, the result revealed that XRCC1, IL-8, and Bcl-2 were upregulated in the Kurdish patients with GC, compared to the healthy control group. Targeting XRCC1, IL-8, and Bcl-2 genes can be an interesting field and promising strategy for cancer treatment.

The role of BCL-2 family proteins in regulating apoptosis and cancer therapy

Apoptosis, as a very important biological process, is a response to developmental cues or cellular stress. Impaired apoptosis plays a central role in the development of cancer and also reduces the efficacy of traditional cytotoxic therapies. Members of the B-cell lymphoma 2 (BCL-2) protein family have pro- or anti-apoptotic activities and have been studied intensively over the past decade for their importance in regulating apoptosis, tumorigenesis, and cellular responses to anticancer therapy. Since the inflammatory response induced by apoptosis-induced cell death is very small, at present, the development of anticancer drugs targeting apoptosis has attracted more and more attention. Consequently, the focus of this review is to summarize the current research on the role of BCL-2 family proteins in regulating apoptosis and the development of drugs targeting BCL-2 anti-apoptotic proteins. Additionally, the mechanism of BCL-2 family proteins in regulating apoptosis was also explored. All the findings indicate the potential of BCL-2 family proteins in the therapy of cancer.

Clinical Differences in c-Myc Expression in Early-Stage Gastric Neoplasia: A Retrospective Study Based on the WHO Classification

c-Myc is an oncogene that is dysregulated in various cancers. Early gastric neoplasia with c-Myc expression has been reported as a more malignant lesion. This study clarifies the differences in c-Myc expression in early gastric neoplasia based on the WHO classification. Samples from 100 patients with differentiated-type early gastric neoplasia, who underwent endoscopic submucosal dissection between March 2020 and January 2021, were stained for c-Myc. One hundred lesions were classified as low-grade dysplasia, high-grade dysplasia, or intramucosal adenocarcinoma. The staining intensity and extent were scored. A hierarchical cluster analysis for a clinicopathological analysis among the groups, the chi-square test, Bonferroni correction, and residual analysis were performed. Subgroup one and two consisted of 39 patients; while subgroup three consisted of 22. Significant differences among various characteristics were observed between these subgroups. The frequency of low-grade dysplasia was significantly higher, while that of high-grade dysplasia was significantly lower in subgroup three. The frequency of intramucosal adenocarcinoma was significantly higher in subgroup one. The c-Myc positivity rate was significantly higher in subgroup one compared with that in subgroup three. c-Myc expression distinctly differed in early gastric neoplasia. c-Myc-negative low-grade dysplasia may be separately categorized from c-Myc-positive low-grade dysplasia, high-grade dysplasia, and intramucosal adenocarcinoma.

Stomach-specific c-Myc overexpression drives gastric adenoma in mice through AKT/mammalian target of rapamycin signaling

Gastric cancer (GC) is one of the most common malignant cancers in the world. c-Myc, a well-known oncogene, is commonly amplified in many cancers, including gastric cancer. However, it is still not completely understood how c-Myc functions in GC. Here, we generated a stomach-specific c-Myc transgenic mouse model to investigate its role in GC. We found that overexpression of c-Myc in Atp4b+ gastric parietal cells could induce gastric adenoma in mice. Mechanistically, c-Myc promoted tumorigenesis via the AKT/mTOR pathway. Furthermore, AKT inhibitor (MK-2206) or mTOR inhibitor (Rapamycin) inhibited the proliferation of c-Myc overexpressing gastric cancer cell lines. Thus, our findings highlight that gastric tumorigenesis can be induced by c-Myc overexpression through activation of the AKT/mTOR pathway.

Weipiling ameliorates gastric precancerous lesions in Atp4a-/- mice

Background

Altered cellular metabolism is considered to be one of the hallmarks of cancer (Coller, Am J Pathol 184:4–17, 2014; Kim and Bae, Curr Opin Hematol 25:52–59, 2018). However, few studies have investigated the role of metabolism in the development of gastric precancerous lesions (GPLs). Weipiling (WPL), a traditional Chinese medicine formula for treatment of GPLs. In this study, we evaluated the amelioration of GPLs by WPL and investigated the possible role of WPL in regulating glucose metabolism.

Methods

Firstly, the major components of WPL are chemically characterized by HPLC analytical method. In this study, we chose the Atp4a^−/− mouse model (Spicer etal., J Biol Chem 275:21555–21565, 2000) for GPL analysis. Different doses of WPL were administered orally to mice for 10 weeks. Next, the pathological changes of gastric mucosa were assessed by the H&E staining and AB-PAS staining. In addition, TUNEL staining was used to evaluate apoptosis, and we further used immunohistochemically labelled CDX2, MUC2, ki-67, PTEN, and p53 proteins to assess the characteristic changes of gastric mucosa in precancerous lesions. The levels of such transporters as HK-II, PKM2, ENO1, MPC1, and LDHA were determined by Western blot analysis. Finally, we assessed the expression of mTOR, HIF-1α, AMPK, Rheb, TSC1 and TSC2 protein in the gastric mucosa of Atp4a^−/−mice.

Results

In this work, we evaluated the protective effect of WPL on gastric mucosa in mice with precancerous lesions. The aberrant apoptosis in gastric mucosa of gastric pre-cancerous lesions was controlled by WPL (P<0.05). Furthermore, WPL suppressed the expression of CDX2, MUC2, ki-67, PTEN and p53, as the levels of these proteins decreased significantly compared with the model group (P<0.05). In parallel, WPL significantly suppressed the expression of transporters, such as HK-II, PKM2, ENO1, MPC1 and LDHA (P<0.05). In addition, mTOR, HIF-1a, AMPK, Rheb, TSC1 and TSC2 protein levels in gastric mucosa of Atp4a^−/− mice in the high- and low-dose WPL groups were significantly lower than those in the model group (P<0.05), while the expression of TSC1 and TSC2 protein was significantly higher (P<0.05).

Conclusions

Conclusively, WPL could ameliorate GPLs in Atp4a^−/− mice by inhibiting the expression of transporters and suppressing the aberrant activation of mTOR/HIF-1α.

LMX1A inhibits C-Myc expression through ANGPTL4 to exert tumor suppressive role in gastric cancer

Our research group has showed that the LIM homeobox transcription factor 1 alpha (LMX1A) is inactivated in gastric cancers. Overexpression of LMX1A inhibits tumor growth. However, the mechanisms remains unclear. Considering LMX1A as a transcription factor, a comparison of RNA-seq between gastric cancer cells (GCCs) and GCCs with LMX1A overexpressed was performed to identify genes transcriptionally activated by LMX1A. Among the potential LMX1A target genes, angiopoietin-like 4 (ANGPTL4) has been reported to be an important tumor suppressor and thus was selected for further validation and research. Both LMX1A and ANGPTL4 showed downregulated expression in gastric cancer samples. More importantly, the expression of LMX1A is positively correlated with ANGPTL4, without including other family members in gastric cancer cell lines. What’s more, knockdown of ANGPTL4 rescued the tumor suppressive phenotype of LMX1A overexpression, which indicated that LMX1A upregulates ANGPTL4 to exert its role. Mechanistically, we found that LMX1A inhibited the expression of the oncogene C-Myc, which is alleviated by ANGPTL4 knockdown. In general, our results showed that LMX1A exerts its tumor suppressive role by activating ANGPTL4 to inhibit C-Myc.

The diagnostic value of serum gastrokine 1 (GKN1) protein in gastric cancer

Early detection of cancer provides effective treatment and saves lives. The objective of this study was to determine whether serum gastrokine 1 (GKN1) protein is a gastric cancer-specific diagnostic biomarker. The serum concentration of GKN1 in healthy individuals (median: 6.34 ng/μL, interquartile range (IQR): 5.66-7.54 ng/μL) was significantly higher compared with the levels in gastric cancer patients (median: 3.48 ng/μL, IQR: 2.90-4.11 ng/μL; P < .0001). At the optimum cutoff (4.94 ng/μL) of serum GKN1 protein, the sensitivity and specificity were 91.2% and 96.0%, respectively, for gastric cancer. Using serum GKN1 protein as the diagnostic reference, the ROC curve showed a satisfactory diagnostic efficacy with an AUC value of 0.9954 (95% CI 0.9919-0.9988) and Youden index of 0.8740. In addition, the diagnostic accuracy of the serum GKN1 protein at the optimum cutoff was 0.9675. Interestingly, serum GKN1 concentrations in patients with advanced gastric cancer (AGC; median: 3.11 ng/μL, IQR: 2.72-3.72 ng/μL) were lower than in patients with early gastric cancer (EGC; median: 4.31 ng/μL, IQR: 3.88-4.88 ng/μL). The diagnostic accuracies at the optimum serum GKN1 cutoff were 0.8912 and 0.9589 for EGC and AGC, respectively. Furthermore, the serum GKN1 concentrations robustly discriminated the patients with gastric cancer from the patients with colorectal, liver, lung, breast, pancreatic, ovary, and prostatic cancers with AUC values greater than 0.94. These data suggest that serum GKN1 is a promising and highly specific diagnostic biomarker for the prompt detection of early and advanced gastric cancers.

XZ-1 regulates cell apoptosis of gastric epithelial dysplasia via NF-κB/p53/Ki67 signaling pathway

We aimed to determine the effect of ‘Xiaozeng No. 1’ (XZ-1) on cellular apoptosis changes of gastric epithelial dysplasia (GED) and to explore the underlying mechanism. Specimens taken from the pyloric area of the stomachs from rats in each group were subjected to Hematoxylin and Eosin (H&E) staining for pathological examination, TUNEL staining for apoptosis detection, and Western blot analysis for apoptosis-related proteins. The results showed that XZ-1 decreased GED incidence and enhanced gastric epithelial apoptosis. Furthermore, XZ-1 up-regulated the proapoptotic proteins including cleaved caspases (cysteine-dependent aspartate-specific protease) (-3, -8, and -9), Fas, Bax, and Bid, and facilitated the release of cytochrome c from mitochondria to the cytoplasm. Interestingly, XZ-1 enhanced protein expression of NF-κB p65, Ki67, and p53. Moreover, inhibition of NF-κB pathway suppressed the XZ-induced p53 expression, whereas inhibition of NF-κB or p53 pathway suppressed the XZ-induced Ki67. More importantly, inhibition of NF-κB or p53 pathway attenuated the XZ-1-mediated induction of gastric epithelial apoptosis and decline of GED incidence. Collectively, our results demonstrated that XZ-1, almost equivalent effect exerted by the positive control Retin-A, dramatically decreased GED incidence and enhanced gastric epithelial apoptosis. Meanwhile, XZ-1 activated the NF-κB/p53/Ki67-apoptosis signaling pathway, which might be one of the mechanisms whereby XZ-1 reversed GED.

Circulating SH2B1 is associated with an increased risk of gastric cancer

Gastric cancer (GC) is one of the most common types of cancer in humans and the second leading cause of cancer-associated mortality worldwide. Identifying novel risk factors will facilitate the development of therapeutic strategies to prevent and treat GC. Increased expression of the Src homology 2 B adaptor protein 1 (SH2B1) may stimulate the malignant progression of lung cancer, esophageal cancer and neuroblastoma. However, its function in GC has not yet been investigated. To identify whether increased serum SH2B1 is a risk factor for GC, the present study performed a nested case-control study of patients within the Chinese cohort study. Levels of serum SH2B1 were measured in 563 patients diagnosed with GC during the follow-up period and in 1,126 matched healthy controls. The results demonstrated that high levels of serum SH2B1 were associated with an increased GC risk (odds ratio, 3.23; 95% confidence interval, 2.45-5.65). When analyses were stratified further by sex, age and smoking, an association between increased levels of SH2B1 and GC was identified in males but not in females. Furthermore, the association between SH2B1 levels and GC was more evident in younger than in older participants, and statistically significant in current smokers but not in nonsmokers. These results were not altered following the exclusion of outliers. Furthermore, it was demonstrated that overexpression of SH2B1 contributes to the malignant transformation of normal gastric epithelial cells. Thus, the present study demonstrated that elevated serum SH2B1 levels may increase the risk of GC.

HPV, KRAS mutations, alcohol consumption and tobacco smoking effects on esophageal squamous-cell carcinoma carcinogenesis

Esophageal squamous-cell carcinoma (ESCC) is an invasive neoplastic disease generally associated with poor survival rates. The incidence of ESCC is characterized by marked geographic variation, with highest rates noted in developing Southeastern African, Central and Eastern Asian countries. In the developed Western European and North American regions where there is a low disease incidence, heavy alcohol and cigarette consumption constitute major risk factors. The toxic effects of both these risk factors cause chronic irritation and inflammation of the esophageal mucosa, while at the cellular level they further confer mutagenic effects by the activation of oncogenes (e.g., RAS mutations), inhibition of tumor-suppressor genes, and profound DNA damage. Viral infections, particularly with human papillomavirus, may activate specific antiapoptotic, proliferative and malignant cellular responses that may be intensified in combination with the effects of alcohol and tobacco. In countries with a high ESCC incidence, low socioeconomic status and an inadequate diet of poorly preserved food are combined with basic nutritional deficiencies and inadequate medical treatment. These conditions are favorable to the above-mentioned risk factors implicated in ESCC development, which may be present and/or habitually used in certain populations. New perspectives in epidemiological studies of ESCC development and its risk factors allow genome-wide research involving specific environments and habits. Such research should consist of adequately large and representative samples, should use newly designed informative genetic markers, and apply genomic variation analysis of the functional transcripts involved in malignant cell cycle regulation and neoplastic transformation in the multi-step process of ESCC carcinogenesis.

Identifying prognostic signature in ovarian cancer using DirGenerank

Identifying the prognostic genes in cancer is essential not only for the treatment of cancer patients, but also for drug discovery. However, it's still a big challenge to select the prognostic genes that can distinguish the risk of cancer patients across various data sets because of tumor heterogeneity. In this situation, the selected genes whose expression levels are statistically related to prognostic risks may be passengers. In this paper, based on gene expression data and prognostic data of ovarian cancer patients, we used conditional mutual information to construct gene dependency network in which the nodes (genes) with more out-degrees have more chances to be the modulators of cancer prognosis. After that, we proposed DirGenerank (Generank in direct netowrk) algorithm, which concerns both the gene dependency network and genes' correlations to prognostic risks, to identify the gene signature that can predict the prognostic risks of ovarian cancer patients. Using ovarian cancer data set from TCGA (The Cancer Genome Atlas) as training data set, 40 genes with the highest importance were selected as prognostic signature. Survival analysis of these patients divided by the prognostic signature in testing data set and four independent data sets showed the signature can distinguish the prognostic risks of cancer patients significantly. Enrichment analysis of the signature with curated cancer genes and the drugs selected by CMAP showed the genes in the signature may be drug targets for therapy. In summary, we have proposed a useful pipeline to identify prognostic genes of cancer patients.

MOXIBUSTION ALLEVIATES GASTRIC PRECANCEROUS LESIONS IN RATS BY PROMOTING CELL APOPTOSIS AND INHIBITING PROLIFERATION-RELATED ONCOGENES

Background:

It is well known that gastric mucosa dysplasia and intestinal metaplasia are gastric precancerous lesions (GPL). Moxibustion treatment of Liangmen (ST21) and Zusanli (ST36) alleviated the inflammatory response and dysplasia of gastric mucosa in our previous study. The purpose of this study was to further examine the underlying mechanism of moxibustion treatment of ST21 and ST36 on GPL.

Materials and Methods:

Sixty SD rats were divided into five groups and rats with GPL were treated with either moxibustion (ST), moxibustion (Sham), or vitacoenzyme. B-cell lymphoma 2 (bcl-2), tumor protein p53 (P53) and cellular Myc (C-MYC), which are related to cell apoptosis, proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), argyrophilic nucleolar organizer region proteins (Ag-NORs), which are associated with cell proliferation, and cell signaling proteins, nuclear factor kappa B (NF-κB), epidermal growth factor receptor (EGFR) and phosphorylated extracellular signal regulated kinase (p-ERK), were measured after moxibustion treatment.

Results:

Compared with Control group, gastric mucosa in GPL group showed abnormal mucosal proliferation and pathological mitotic figure, the mRNA expression of bcl-2, P53 and C-MYC increased significantly (P < 0.01), the protein expression of PCNA, VEGF, Ag-NORs and the activity of NF-κβ as well as EGFR/ERK signaling proteins also increased significantly (P < 0.01). Moxibustion treatment decreased gastric mucosal proliferation and pathological mitotic figure, down-regulated the mRNA expression of bcl-2, P53, C-MYC (P < 0.01), decreased the protein expression of PCNA, VEGF, Ag-NORs and the activity of NF-κβ as well as EGFR/ERK signaling proteins significantly (P < 0.01). But moxibustion treatment of Sham didn’t show the same effect on GPL.

Conclusion:

Moxibustion treatment inhibited cell apoptosis and reduced gastric mucosa dysplasia by inhibiting the expression of bcl-2, P53, C-MYC and decreased the activity of NF-κβ as well as EGFR/ERK signaling proteins.

Copy Number Gains at 8q24 and 20q11-q13 in Gastric Cancer Are More Common in Intestinal-Type than Diffuse-Type

The present study was aimed at discovering DNA copy number alterations (CNAs) involved in the carcinogenesis of stomach and at understanding their clinicopathological significances in the Korean population. DNA copy numbers were analyzed using Agilent 244K or 400K array comparative genomic hybridization (aCGH) in fresh-frozen tumor and matched normal tissues from 40 gastric cancer patients. Some of the detected CNA regions were validated using multiplex ligation-dependent probe amplification (MLPA) in six of the 40 patients and customized Agilent 60K aCGH in an independent set of 48 gastric cancers. The mRNA levels of genes at common CNA regions were analyzed using quantitative real-time PCR. Copy number gains were more common than losses across the entire genome in tumor tissues compared to matched normal tissues. The mean number of alterations per case was 64 for gains and 40 for losses, and the median aberration length was 44016 bp for gains and 4732 bp for losses. Copy number gains were frequently detected at 7p22.1 (20%), 8q24.21 (27%-30%), 8q24.3 (22%-48%), 13q34 (20%-31%), and 20q11-q13 (25%-30%), and losses at 3p14.2 (43%), 4q35.2 (27%), 6q26 (23%), and 17p13.3 (20%-23%). CNAs at 7p22.1, 13q34, and 17p13.3 have not been reported in other populations. Most of the copy number losses were associated with down-regulation of mRNA levels, but the correlation between copy number gains and mRNA expression levels varied in a gene-dependent manner. In addition, copy number gains tended to occur more commonly in intestinal-type cancers than in diffuse-type cancers. In conclusion, the present study suggests that copy number gains at 8q24 and 20q11-q13 and losses at 3p14.2 may be common events in gastric cancer but CNAs at 7p22.1, 13q34, and 17p13.3 may be Korean-specific.

Study of C-MYC amplification and expression in Iranian gastric cancer samples using CISH and IHC methods

Background:

Gastric cancer is the fourth most frequent malignancy and the second cause of cancer-related mortality worldwide. It has been suggested that in gastric carcinogenesis, the C-MYC gene has an important function. The objective of this study is to establish the preference of Chromogenic in situ hybridization (CISH) and Immunohistochemistry (IHC) in the diagnosis and prognosis of gastric cancer.

Materials and Methods:

Samples comprised of 50 randomly selected patients of whom 40 were male and 10 female. To evaluate the MYC copy number and its protein expression, CISH and IHC analyses were performed for 50 gastric adenocarcinomas, in Iran.

Results:

The location of the tumor in 64% of the patients was the fundus, and in 72% of patients, the tumors were of a diffuse type; 22 samples showed no amplification, and 28 samples were with amplification. MYC immunoreactivity was observed in 13 samples. Twelve samples showed both MYC amplification and MYC immunoreactivity. In addition, among the 28 CISH+ samples, 12 samples had positive signals for IHC and 16 samples had negative signals for IHC. A majority of the IHC-negative patients had no amplification, but only one patient with IHC positive had no amplification.

Conclusion:

Our conclusion was that for the management and treatment of gastric cancer, and for special attention of clinicians, for prognosis and tumor progression, the CISH was a better and more feasible test than IHC, in regard to the sensitivity and specificity.

Identification of volatile biomarkers of gastric cancer cells and ultrasensitive electrochemical detection based on sensing interface of Au-Ag alloy coated MWCNTs

Successful development of novel electrochemical biosensing interface for ultrasensitive detection of volatile biomarkers of gastric cancer cells is a challenging task. Herein we reported to screen out novel volatile biomarkers associated with gastric cancer cells and develop a novel Au-Ag alloy composites-coated MWCNTs as sensing interface for ultrasensitive detection of volatile biomarkers. MGC-803 gastric cancer cells and GES-1 gastric mucous cells were cultured in serum-free media. The sample preparation approaches and HS-SPME conditions were optimized for screening volatile biomarkers. Volatiles emitted from the headspace of the cells/medium culture were identified using GC-MS. The Au-Ag nanoparticles-coated multiwalled carbon nanotubes were prepared as a sensing interface for detection of volatile biomarkers. Results showed that eight different volatile metabolites were screened out between MGC-803 cells and GES-1 cells. Two compounds such as 3-octanone and butanone were specifically present in the headspace of the MGC-803 cells. Three volatiles such as 4-isopropoxybutanol, nonanol and 4-butoxy 1-butanol coexisted in the headspace of both the MGC-803 cells and the GES-1 cells, their concentrations in the headspace of the GES-1cells were markedly higher than those in the MGC-803 cells, three volatiles such as formic acid propyl ester, 1.4-butanediol and 2, 6, 11-trimethyl dodecane solely existed in the headspace of the GES-1 cells. The nanocomposites of MWNTs loaded with Au-Ag nanoparticles were prepared as a electrochemical sensing interface for detection of two volatile biomarkers, cyclic voltammetry studies showed that the fabricated sensor could detect 3-octanone in the range of 0~0.0025% (v/v) and with a detection limitation of 0.3 ppb, could detect butanone in the range of 0 ~ 0.055% (v/v), and with a detection limitation of 0.5 ppb, and exhibited good selectivity. The novel electrochemical biosensor combined with volatile biomarkers of gastric cancer owns great potential in applications such as early diagnosis and the prognosis of gastric cancer in near future.

BRCAA1 antibody- and Her2 antibody-conjugated amphiphilic polymer engineered CdSe/ZnS quantum dots for targeted imaging of gastric cancer

Successful development of safe and highly effective nanoprobes for targeted imaging of in vivo early gastric cancer is a great challenge. Herein, we choose the CdSe/ZnS (core-shell) quantum dots (QDs) as prototypical materials, synthesized one kind of a new amphiphilic polymer including dentate-like alkyl chains and multiple carboxyl groups, and then used the prepared amphiphilic polymer to modify QDs. The resultant amphiphilic polymer engineered QDs (PQDs) were conjugated with BRCAA1 and Her2 monoclonal antibody, and prepared BRCAA1 antibody- and Her2 antibody-conjugated QDs were used for in vitro MGC803 cell labeling and in vivo targeted imaging of gastric cancer cells. Results showed that the PQDs exhibited good water solubility, strong photoluminescence (PL) intensity, and good biocompatibility. BRCAA1 antibody- and Her2 antibody-conjugated QD nanoprobes successfully realized targeted imaging of in vivo gastric cancer MGC803 cells. In conclusion, BRCAA1 antibody- and Her2 antibody-conjugated PQDs have great potential in applications such as single cell labeling and in vivo tracking, and targeted imaging and therapeutic effects' evaluation of in vivo early gastric cancer cells in the near future.

Expression profile as predictor of relapse after adjuvant treatment in gastric cancer

INTRODUCTION

TNM and histological subtype are the most important prognostic criteria in gastric cancer. In this study, we have tried to identify an immunohistochemical protein profile involved in gastric recurrence after a radical surgery.

MATERIALS AND METHODS

In this paper, protein panels involved in gastric carcinogenesis and progression was analyzed by immunohistochemistry expression: p53, Ki-67, Bcl-2, COX-2, c-erb-B2, EPO-R, E-cadherin, and β-catenin in 44 gastrectomy samples coming from gastrectomy pieces of patients diagnosed and operated on adenocarcinoma of the stomach followed by adjuvant treatment based on MacDonald chemoradiation regimen. An immunostaining profile that could predict the relapse after the end of adjuvant treatment was tried to find. These results have shown that the expression of the adverse prognostic protein profile based on positive p53 immunohistochemical expression and non-conserved E-cadherin/B-catenin staining is associated with tumor recurrence and a poor disease-free survival in operated gastric cancer patients with curative intent followed by adjuvant chemoradiation according to MacDonald's regimen. A protein profile based on immunohistochemical expression of p53 and E-cadherin-B-catenin that has a significant correlation to disease-free survival was identified in gastric cancer samples.

DiR-labeled Embryonic Stem Cells for Targeted Imaging of in vivo Gastric Cancer Cells

Embryonic stem (ES) cells have great potential in applications such as disease modeling, pharmacological screening and stem cell therapies. Up to date, there is no related report on the use of ES cells as tracking and contrast reagents of cancer cells in vivo. Herein we report that DiR-labeled murine ES cells can recognize and target gastric cancer cells in vivo. DiR-labeled murine ES (mES) cells (5×10(6)) were intravenously injected into gastric tumor-bearing mice. The biodistribution of DiR-labeled mES cells was monitored by IVIS imaging within 24 h. Major organs were harvested and analyzed by immunofluorescence staining and Western blotting. Chemotaxis assay was employed to investigate the chemotaxis of ES cells tracking cancer cells. Fluorescent imaging results showed that DiR-labeled mES cells targeted gastric cancer tissue in vivo as early as 10 min post-injection, reaching a peak at 2h post-injection. Immunofluorescence staining and Western blotting results showed gastric cancer tissues specifically expressed SSEA-1. In vitro migration tests confirmed that mES cells actively moved to test sites with different concentration of CXCL12 in a dose-dependent manner. In conclusion, DiR-labeled mES cells may be used for gastric cancer targeted imaging in vivo, and have great potential in applications such as identifying and imaging of early gastric cancer in near future.

15-PGDH is reduced and induces apoptosis and cell cycle arrest in gastric carcinoma

AIM: To investigate the expression of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in human gastric cancer and it’s mechanism in apoptosis and cell cycle arrest.

METHODS: Expression of 15-PGDH mRNA and protein was examined by immunohistochemistry, immunocytochemistry, reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting in tissue from human gastric cancer, gastric precancerous state (gastric polyps and atrophic gastritis), normal stomach, and gastric cancer cell lines. The relationship between gastric cancer, gastric precancerous state and 15-PGDH expression was determined. The association between expression of 15-PGDH and various clinicopathological parameters in gastric cancer was evaluated. Human gastric cancer cell line SGC-7901 was transfected with 15-PGDH expression plasmids. The effect of 15-PGDH on the cell cycle was examined by flow cytometry. The effect of 15-PGDH on apoptosis was examined by transmission electron microscopy, flow cytometry and transferase mediated nick end labeling (TUNEL) assay. Expression of cell cycle (p21, p27, p16 and p53) and apoptosis (Survivin, BCL-2, BCL-X_L, BAK and BAX) genes was analyzed by RT-PCR.

RESULTS: Expression of 15-PGDH mRNA and protein in human gastric cancer tissues was significantly lower than in normal gastric tissues (P < 0.01). Expression in human gastric cancer cell lines MKN-28 and MKN-45 was reduced, and absent in SGC-7901 cells (P < 0.05). Reduction of 15-PGDH expression was also found in precancerous tissues, such as gastric polyps and atrophic gastritis (P < 0.01). There was a significant difference in expression of 15-PGDH among various gastric cancer pathological types (P < 0.05), with or without distant metastasis (P < 0.05) and different TNM stage (P < 0.01). Flow cytometry demonstrated a significant increase in apoptotic cells in SGC-7901 cells transfected with pcDNA3/15-PGDH plasmid for 24 h and 48 h (P < 0.01), and an increased fraction of sub-G1 phase after transfection (P < 0.05). TUNEL assay showed an increased apoptotic index in cells overexpressing 15-PGDH (P < 0.01). After transfection, expression of proapoptotic genes, such as BAK (P < 0.05), BAX and p53 (P < 0.01), was increased. Expression of antiapoptotic genes was decreased, such as Survivin, BCL-2 and BCL-X_L (P < 0.01). Expression of cyclin-dependent kinase inhibitors p21 and p16 (P < 0.01) was significantly upregulated in cells overexpressing 15-PGDH.

CONCLUSION: Reduction of 15-PGDH is associated with carcinogenesis and development of gastric carcinoma. 15-PGDH induces apoptosis and cell cycle arrest in SGC-7901 cells.

Down-regulation of c-Myc expression inhibits the invasion of bile duct carcinoma cells

Cholangiocarcinoma is the second most common primary hepatic tumour originating from biliary tract epithelial cells with poor prognosis. Enhanced c-Myc protein expression contributes to many aspects of tumour cell biology. Although the ability of c-Myc to drive unrestricted cell proliferation and to inhibit cell differentiation had been well recognized, whether down-regulated c-Myc expression can inhibit tumour cell invasion still remains to be explored. The c-Myc ASODN (antisense oligodeoxyribonucleotide) and NSODN (nonsense oligodeoxyribonucleotide) were designed, synthesized and transfected into human QBC939 bile duct carcinoma cells using the Lipofectamine 2000 reagent. The protein expression of c-Myc was detected by Western blot. A transwell experiment was applied to evaluate the invasive capacity of the QBC939 cells. c-Myc ASODN could significantly suppress the c-Myc protein expression (P<0.05) and the invasion (P<0.01) of QBC939 cells transfected with c-Myc ASODN compared with that in the control and c-Myc NSODN-transfected group. Thus in the present study we show that down-regulation of c-Myc expression can inhibit the invasion of QBC939 cells in vitro.

Synthesis, characterization and anti proliferative effect of [Au(en)2]Cl3 and [Au(N-propyl-en)2]Cl3 on human cancer cell lines

Two Au(III) complexes of the type [Au(en)2]Cl3 (2a) and [Au(N-pr-en)2]Cl3 (3a) were synthesized by reacting Auric acid (HAuCl(4)·3H2O) with 2 equiv. ethylenediamine (en) or N-alkyl substituted ethylenediamine ligands. This metallodrug was characterized by various analytical and spectroscopic techniques such as elemental analysis, UV-Vis, Far-IR, 1H NMR and solution 13C as well as solid 13C and 15N NMR. Potentiality of [Au(en)2]Cl3 and [Au(N-pr-en)2]Cl3 as an anti-cancer agent were investigated by measuring some relevant physicochemical and biochemical properties such as stability of Au-N bonds by vibrational stretching from Far IR as well as cytotoxicity and stomach cancer cell inhibiting effect, respectively. The solid-state 15N NMR chemical shift shows that the ligand is strongly bound to gold(III) centre via N atoms. The computational study of 2a shows that the gold coordination sphere adopts distorted square planar geometry with bidentate ethylenediamine ligands acting as a tetradentate chelate. While stable in the solution state, the in vitro biological studies performed with these compounds 2a in solution showed higher activity towards the inhibitory effects of the human cancer cell lines such as prostate cancer (PC-3) and gastric carcinoma (SGC-7901) than that of the N-substituted gold(III) complex (3a). Cytotoxicity of the new compounds has also been estimated in PC-3 and SGC-7901 cells.

miR-429 modulates the expression of c-myc in human gastric carcinoma cells

AIM

MicroRNAs (miRNAs) are a recently discovered class of small non-coding RNAs that regulate gene expression and may contribute to the development and progression of many cancers. In this study, our goal was to investigate the regulation of miR-429 in gastric cancer and explored the mechanism/s by which it influenced pathogenesis of gastric cancer.

METHODS

We used real-time reverse transcriptase-polymerase chain reaction to quantify the expression level of miR-429 in 52 gastric cancer tissues and their paracancerous tissues. Bioinformatics was used to predict downstream target genes of miR-429. SGC-7901 gastric cancer cells were transfected with miR-429 mimics and endogenous c-myc expression was detected by western blots. We performed functional assays using the 3'UTR of the c-myc gene as a miR-429 target in a luciferase reporter assay system.

RESULTS

We showed that miR-429 was downregulated in human gastric carcinoma tissue and in SGC-7901 cells. Cell viability, proliferation and attachment were inhibited in miR-429-transfected cells. miR-429 significantly downregulated endogenous c-myc expression in SGC-7901 cells. Action of miR/429 on c-myc 3'UTR was confirmed. The levels of miR-429 in tumour tissue of patients with lymph node metastasis were significantly lower than in those without lymph node metastasis.

CONCLUSIONS

Our results suggested that miR-429 played a role in the pathogenesis of gastric carcinoma and may function as a recessive cancer gene. c-myc is an important miR-429 target gene.

BRCAA1 monoclonal antibody conjugated fluorescent magnetic nanoparticles for in vivo targeted magnetofluorescent imaging of gastric cancer

BACKGROUND

Gastric cancer is 2th most common cancer in China, and is still the second most common cause of cancer-related death in the world. How to recognize early gastric cancer cells is still a great challenge for early diagnosis and therapy of patients with gastric cancer. This study is aimed to develop one kind of multifunctional nanoprobes for in vivo targeted magnetofluorescent imaging of gastric cancer.

METHODS

BRCAA1 monoclonal antibody was prepared, was used as first antibody to stain 50 pairs of specimens of gastric cancer and control normal gastric mucous tissues, and conjugated with fluorescent magnetic nanoparticles with 50 nm in diameter, the resultant BRCAA1-conjugated fluorescent magnetic nanoprobes were characterized by transmission electron microscopy and photoluminescence spectrometry, as-prepared nanoprobes were incubated with gastric cancer MGC803 cells, and were injected into mice model loaded with gastric cancer of 5 mm in diameter via tail vein, and then were imaged by fluorescence optical imaging and magnetic resonance imaging, their biodistribution was investigated. The tissue slices were observed by fluorescent microscopy, and the important organs such as heart, lung, kidney, brain and liver were analyzed by hematoxylin and eosin (HE) stain method.

RESULTS

BRCAA1 monoclonal antibody was successfully prepared, BRCAA1 protein exhibited over-expression in 64% gastric cancer tissues, no expression in control normal gastric mucous tissues, there exists statistical difference between two groups (P < 0.01). The BRCAA1-conjugated fluorescent magnetic nanoprobes exhibit very low-toxicity, lower magnetic intensity and lower fluorescent intensity with peak-blue-shift than pure FMNPs, could be endocytosed by gastric cancer MGC803 cells, could target in vivo gastric cancer tissues loaded by mice, and could be used to image gastric cancer tissues by fluorescent imaging and magnetic resonance imaging, and mainly distributed in local gastric cancer tissues within 12 h post-injection. HE stain analysis showed that no obvious damages were observed in important organs.

CONCLUSIONS

The high-performance BRCAA1 monoclonal antibody-conjugated fluorescent magnetic nanoparticles can target in vivo gastric cancer cells, can be used for simultaneous magnetofluorescent imaging, and may have great potential in applications such as dual-model imaging and local thermal therapy of early gastric cancer in near future.

Differential expression of MYC in H. pylori-related intestinal and diffuse gastric tumors

Evidence suggests that the carcinogenic process guided by Helicobacter pylori is related to the expression of cell cycle and apoptosis proteins as BCL-2, BAX, and MYC. However, the literature is conflicting regarding the expression frequency in the histological subtypes and did not consider cagA gene presence. To investigate the expression of these proteins considering the histological subtypes of gastric cancer associated with H. pylori (cagA), a total of 89 cases were used. H. pylori infection and cagA status were determined by PCR. Immunodetection was performed for MYC, BCL-2, and BAX proteins. H. pylori was found in 95.5% of the patients, among them, 65.8% were cagA(+). Nuclear MYC was detected in 36.4%, BAX in 55.7%, while BCl-2 in just 5%. Nuclear MYC staining was significantly lower in the intestinal than diffuse subtype (p = 0.008) and was related with the presence of H. pylori cagA(+). Additionally, most of the few cases cytoplasmic MYC positive were in the intestinal subtype. In diffuse tumors, although most nuclear MYC positive cases were cagA(+), it was not significant. No difference was observed between BCL-2 or BAX expression considering the presence of cagA gene in the histological subtypes. It seems that MYC could be relevant for the diffuse tumorigenic pathway associated with H. pylori and possibly influenced by the presence of cagA gene, while in intestinal tumors, the tumorigenic pathway does not occur through the MYC expression.

The impact of C-MYC gene expression on gastric cancer cell

The upregulation or mutation of C-MYC has been observed in gastric, colon, breast, and lung tumors and in Burkitt's lymphoma. However, little is known about the role C-MYC plays in gastric adenocarcinoma. In the present study, we intended to investigate the influence of C-MYC on the growth, proliferation, apoptosis, invasion, and cell cycle of the gastric cancer cell line SGC7901 and the gastric cell line HFE145. C-MYC cDNA was subcloned into a constitutive vector PCDNA3.1 followed by transfection in normal gastric cell line HFE145 by using liposome. Then stable transfectants were selected and appraised. Specific inhibition of C-MYC was achieved using a vector-based siRNA system which was transfected in gastric cancer cell line SGC7901. The apoptosis and cell cycles of these clones were analyzed by using flow cytometric assay. The growth and proliferation were analyzed by cell growth curves and colony-forming assay, respectively. The invasion of these clones was analyzed by using cell migration assay. The C-MYC stable expression clones (HFE-Myc) and C-MYC RNAi cells (SGC-MR) were detected and compared with their control groups, respectively. HFE-Myc grew faster than HFE145 and HFE-PC (HFE145 transfected with PCDNA3.1 vector). SGC-MR1, 2 grew slower than SGC7901 and SGC-MS1, 2 (SGC7901 transfected with scrambled control duplexes). The cell counts of HFE-Myc in the third, fourth, fifth, sixth, and seventh days were significantly more than those of control groups (P < 0.05). Those of SGC-MR1, 2 in the fourth, fifth, sixth, and seventh days were significantly fewer than those of control groups (P < 0.05). Cell cycle analysis showed that proportions of HFE-Myc and SGC-MR cells in G0-G1 and G2-M were different significantly with their control groups, respectively (P < 0.05). The apoptosis rate of HFE-Myc was significantly higher than those of control groups (P < 0.05). Results of colony-forming assay showed that the colony formation rate of HFE-Myc was higher than those of control groups; otherwise, the rate of SGC-MR was lower than those of their control groups (P < 0.05). The results of cell migration assay showed that there were no significant differences between experimental groups and control groups (P > 0.05). In conclusion, C-MYC can promote the growth and proliferation of normal gastric cells, and knockdown of C-MYC can restrain the growth and proliferation of gastric cancer cells. It can induce cell apoptosis and help tumor cell maintain malignant phenotype. But it can have not a detectable influence on the ability of invasion of gastric cancer cells.

The role of oncogenes in gastrointestinal cancer

Oncogene research over the last century has been one of the major advances in understanding the molecular biology of malignant disease. Oncogenes are a structurally and functionally heterogeneous group of genes, whose protein products act pleiotropically and affect multiple complex regulatory cascades within the cell. They regulate cell proliferation, growth, and differentiation, as well as control of the cell cycle and apoptosis. The products of oncogenes include growth factors, growth factor receptors, signal transducers, transcription factors, and apoptosis regulators, as well as chromatin remodelers. Several distinct mechanisms have been described for the conversion of proto-oncogenes to active oncogenes. Quantitative forms of oncogene activation include multiplication (gene amplification) or translocation to an active chromatin domain that brings a growth-regulatory gene under the control of a different promoter, causing inappropriate expression of the gene. Qualitative forms include either point mutations or the production of a novel product from a chimeric gene. Further understanding of the molecular mechanisms by which oncogenes regulate normal development and tumorigenesis may lead to novel concepts in the diagnosis and treatment of cancer in humans. In this review, we focus on the role of selected oncogenes in gastrointestinal cancer.

Localization of N-myc downstream-regulated gene 1 in gastric cancer tissue

BACKGROUND AND AIM

N-myc downstream-regulated gene 1 is detected in normal tissue but is down-regulated in cancer tissue. Furthermore, research has suggested that co-expression with p53 is necessary for induction of p53-mediated apoptosis. This study sought to investigate the clinicopathological significance of N-myc downstream-regulated gene 1 and p53 expression in gastric cancer tissue.

PATIENTS AND METHODS

Immunohistochemical detection of N-myc downstream-regulated gene 1 and p53 was performed with tissue samples from 96 cases of gastric cancer, and the relationship between expression profiles of proteins and clinicopathological characteristics was statistically analysed.

RESULTS

Positive staining of N-myc downstream-regulated gene 1 was observed in the cytoplasm (22 of 96 cases, 22.9%) and/or nucleus (29 of 96 cases, 30.2%) of cancer cells. In 15 cases (15.6%), both cytoplasm-positive cells and nucleus-positive cells were observed in the cancerous region. The nuclear localization of N-myc downstream-regulated gene 1 was frequently observed in the region of cancerous invasion and was significantly related to lymph node metastasis. In addition, accumulation of p53 protein in the nucleus of cancer cells significantly coincided with the nuclear localization of N-myc downstream-regulated gene 1.

CONCLUSIONS

Localization of N-myc downstream-regulated gene 1 and its significant correlation with p53 expression may play an important role in cancer progression.

MYC and gastric adenocarcinoma carcinogenesis

MYC is an oncogene involved in cell cycle regulation, cell growth arrest, cell adhesion, metabolism, ribosome biogenesis, protein synthesis, and mitochondrial function. It has been described as a key element of several carcinogenesis processes in humans. Many studies have shown an association between MYC deregulation and gastric cancer. MYC deregulation is also seen in gastric preneoplastic lesions and thus it may have a role in early gastric carcinogenesis. Several studies have suggested that amplification is the main mechanism of MYC deregulation in gastric cancer. In the present review, we focus on the deregulation of the MYC oncogene in gastric adenocarcinoma carcinogenesis, including its association with Helicobacter pylori (H pylori) and clinical applications.

Interrelationship between MYC gene numerical aberrations and protein expression in individuals from northern Brazil with early gastric adenocarcinoma

Gastric cancer is the second leading cause of death by cancer in Brazil. Early gastric cancer represents approximately 10% of gastric cancer cases in some services of Brazil, which underscores the need for early gastric cancer diagnosis that could lead to better prognosis. There are few published studies of cytogenetic alterations in early gastric cancer. To evaluate MYC copy number and its protein expression, we performed fluorescence in situ hybridization and immunohistochemical analyses in five early gastric adenocarcinomas in individuals from northern Brazil. Three signals of MYC and MYC immunoreactivity were observed in all five samples, regardless of histologic type, tumor extension, or lymph nodal status. These novel findings concerning MYC copy number alteration in early gastric cancer suggest that MYC alteration is observed in the beginning of gastric carcinogenesis and could be used as a therapeutic target.

Effect of vascular endothelial growth factor 165 on apoptosis of human gastric carcinoma cells in vitro and its mechanism

AIM: To investigate the effect of vascular endothelial growth factor 165 (VEGF165) on apoptosis of human gastic adenocarcinoma cell line (BGC-823) in vitro and its underlying mechanism.

METHODS: BGC-823 cells were divided into control group, Ad-GFP group and Ad-VEGF165 group and cultured with GFP (MOI = 20) and Ad-VEGF165. Apoptotic cells were detected by FCM assay. Expression of Bcl-2 mRNA and Bcl-2 protein was determined by RT-PCR and immunocytochemistry, respectively.

RESULTS: FCM showed that the apoptosis rate of BGC-823 cells was significantly lower in the Ad-VEGF165 group than in the Ad-GFP and control groups(4.6% ± 0.31% vs 8.37% ± 1.06%, 7.73% ± 0.86%, P < 0.01). PCR and immunocytochemistry displayed that VEGF165-transfected BGC-823 increased the expression of Bcl-2 mRNA and Bcl-2 protein, which was higher in the Ad-VEGF165 group than in the control and Ad-GFP groups (Bcl-2 mRNA: 0.761 ± 0.05 vs 0.363 ± 0.12, 0.356 ± 0.08; Bcl-2 protein: 1.010 ± 0.08 vs 0.865 ± 0.07, 0.901 ± 0.05; P < 0.01).

CONCLUSION: VEGF165 can inhibit cell apoptosis induced by serum starvation by up-regulating the expression of Bcl-2.

No association between p53 gene intron 7 polymorphism and chronic atrophic gastritis in Han Chinese of Jiangsu province

AIM: To explore whether the polymorphism of p53 gene intron 7 is associated with the occurrence of chronic atrophic gastritis (CAG) in Han Chinese of Jiangsu province.

METHODS: The genome DNA was extracted from tissues of 80 CAG patients and 76 healthy controls, and the exon 7 and 8 as well as the intron 7 within exon 7 and 8 of p53 gene were amplified by polymerase chain reaction (PCR). The products were sequenced after purification. The polymorphism of p53 gene intron 7 was comparatively analyzed with the standard sequences. The genotypes and allelic frequencies compared between the two groups using chi-square test.

RESULTS: In CAG cases, the allelic frequencies of the 72^th base pair (bp) and the 92^th bp in p53 gene intron 7 were 32.5% (T-G) and 67.5% (C-T), and the frequencies of genotype T-G/T-G, C-T/T-G, and C-T/C-T were 11.3%, 42.5%, and 46.3%, respectively. Meanwhile in the controls, the allelic frequencies of T-G and C-T were 29.6% and 70.4%, and the frequencies of genotype T-G/T-G, C-T/T-G, and C-T/C-T were 9.2%, 40.8%, and 50.0%, respectively. There were no significant differences in the allelic frequencies and genotypic distributions between the two groups (P > 0.05). The risk of CAG occurrence was not significantly different between the individuals with T-G and C-T allele (OR = 1.14).

CONCLUSION: There is no direct association between the polymorphism of p53 gene intron 7 and epigenetic penetrance of CAG in Han Chinese of Jiangsu province.

Possible involvement of queuine in regulation of cell proliferation

An increase in cell number is one of the most prominent characteristics of cancer cells. This may be caused by an increase in cell proliferation or decrease in cell death. Queuine is one of the modified base which is found at first anticodon position of specific tRNAs. It is ubiquitously present throughout the living system except mycoplasma and yeast. The tRNAs of Q-family are completely modified to Q-tRNAs in terminally differentiated somatic cells, however hypomodification of Q-tRNA is closely associated with cell proliferation and malignancy. Queuine participates at various cellular functions such as regulation of cell proliferation, cell signaling and alteration in the expression of growth associated proto-oncogenes. Like other proto-oncogenes bcl2 is known to involve in cell survival by inhibiting apoptosis. Queuine or Q-tRNA is suggested to inhibit cell proliferation but the mechanism of regulation of cell proliferation by queuine or Q-tRNA is not well understood. Therefore, in the present study regulation in cell proliferation by queuine in vivo and in vitro as well as the expression of cell death regulatory protein Bcl2 are investigated. For this DLAT cancerous mouse, U87 cell line and HepG2 cell line are treated with different concentrations of queuine and the effect of queuine on cell proliferation and apoptosis are studied. The results indicate that queuine down regulates cell proliferation and expression of Bcl2 protein, suggesting that queuine promotes cell death and participates in the regulation of cell proliferation.

Interrelationship between chromosome 8 aneuploidy, C-MYC amplification and increased expression in individuals from northern Brazil with gastric adenocarcinoma

AIM: To investigate chromosome 8 numerical aberrations, C-MYC oncogene alterations and its expression in gastric cancer and to correlate these findings with histopathological characteristics of gastric tumors.

METHODS: Specimens were collected surgically from seven patients with gastric adenocarcinomas. Immunostaining for C-MYC and dual-color fluorescence in situ hybridization (FISH) for C-MYC gene and chromosome 8 centromere were performed.

RESULTS: All the cases showed chromosome 8 aneuploidy and C-MYC amplification, in both the diffuse and intestinal histopathological types of Lauren. No significant difference (P < 0.05) was observed between the level of chromosome 8 ploidy and the site, stage or histological type of the adenocarcinomas. C-MYC high amplification, like homogeneously stained regions (HSRs) and double minutes (DMs), was observed only in the intestinal-type. Structural rearrangement of C-MYC, like translocation, was observed only in the diffuse type. Regarding C-MYC gene, a significant difference (P < 0.05) was observed between the two histological types. The C-MYC protein was expressed in all the studied cases. In the intestinal-type the C-MYC immunoreactivity was localized only in the nucleus and in the diffuse type in the nucleus and cytoplasm.

CONCLUSION: Distinct patterns of alterations between intestinal and diffuse types of gastric tumors support the hypothesis that these types follow different genetic pathways.

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Cell proliferation and apoptosis in gastric cancer and intestinal metaplasia

BACKGROUND: Higher proliferation is commonly observed in cancer cells. Apoptosis can be a useful measure of a tumor cell kinetic. Alteration of the balance between proliferation and apoptosis is associated with cancer. AIM: To study proliferation and apoptosis on gastric cancer and in intestinal metaplasia. METHODOLOGY: Twenty-two samples from gastric adenocarcinomas and 22 biopsies from intestinal metaplasia were studied. The apoptotic bodies in hematoxylin-eosin slides and the expression of p53, bcl-2 and Ki67 were determined by immunohistochemistry. RESULTS: The number of the apoptotic cells was higher in cancer. Ki 67LI increased from intestinal metaplasia to gastric cancer. p53 was positive in 68% of the patients with cancer, more frequently in advanced stage and negative in samples of intestinal metaplasia. Although there was no significant difference between the groups, bcl-2 was positive in 45% of gastric cancer tissue and in 68% of metaplasia. In gastric cancer patients bcl-2 was expressed in early gastric cancer more frequently than in advanced stage. CONCLUSION: The positivity of bcl-2 was higher in metaplasia and probably is involved in the progression of carcinogenesis. p53 was negative in metaplasia and positive in more than half of the gastric cancer, mostly in stage IV, suggesting a late event in gastric cancer.

Effects of quercetin combined with cisplatin on proliferation and apoptosis of human gastric cancer SGC-7901 cells

AIM: To investigate the effects of quercetin combined with cisplatin on the proliferation and apoptosis of, and the expression of apoptosis-related gene Bcl-X_L in human gastric cancer SGC-7901 cells.

METHODS: After treated with quercetin (QU), cisplatin (DDP) or both (QU-DDP), the viability of SGC-7901 cells was evaluated by MTT assay. Cell cycle distribution and apoptosis were detected by flow cytometry. Cell morphology was examined under light microscope and electron microscope. The expression of Bcl-X_L mRNA was detected by the reverse transcription polymerase chain reaction (RT-PCR).

RESULTS: After exposure to different drugs for 24 h, SGC-7901 cells manifested typical morphological features of apoptosis. Both DDP and QU inhibited the proliferation and induced the apoptosis of SGC7901 cells in a time and concentration-dependent manner. QU combined with DDP synergistically enhanced cell death. The apoptosis was more pronounced in cells treated with both drugs (QU: 1 mmol/L, DDP: 80 mmol/L) than DDP alone (80 mmol/L) (19.930.07 vs 5.160.11, P<0.01). After exposure to DDP for 48 h, Bcl-X_L mRNA expression was down-regulated, which was promoted by QU.

CONCLUSION: QU combined with DDP effectively inhibits proliferation and induces apoptosis of the human gastric cancer SGC-7901 cells in vitro in a dose-dependent manner.

Epstein-Barr virus and aberrant expression of mdm2 and p53 in pathogenesis and development of gastric carcinoma

AIM: To investigate the role of p53 and mdm2 gene abnormality in oncogenesis and development of Epstein-Barr virus (EBV) -associated gastric carcinoma (EBVaGC) and to explore the relationship between EBV infection and p53 and mdm2 protein expression.

METHODS: p53 gene mutation in exon 5-8 was detected by polymerase chain reaction and single strand conformation polymorphism analysis (PCR-SSCP), and DNA sequencing. p53 and mdm2 protein expression was tested by immunohistochemistry in EBVaGCs (n = 13), EBVnGCs (EBV negative gastric carcinomas, n = 45) with matched clinicopathological parameters and corresponding adjacent tissues of gastric carcinoma (n = 58).

RESULTS: The positive rates of p53 and mdm2 protein in gastric carcinomas were significantly higher than those in corresponding adjacent normal tissues (86.2%, 29.3% vs 0%, 0% respectively; P < 0.01). There were no significant difference between the positive rates of p53 and mdm2 protein in EBVnGCs and EBVaGCs. The overexpression rate of p53 protein was 15.4% (2/13) in EBVaGCs. This was in marked contrast to the rate of 57.8% (26/45) in EBVnGCs (χ² = 7.2593, P = 0.0 085 < 0.01). There was significant positive correlation between mdm2 expression and p53 overexpression (χ² = 11.1 839, P = 0.0 008 < 0.01, r = 0.4 391). p53 gene mutation was found in only 2 cases of EBVnGCs and both occurred at exon 5. No p53 gene mutation was detected in 13 cases of EBVaGCs and 58 corresponding adjacent tissues.

CONCLUSION: Abnormal accumulation of p53 protein might not result from p53 gene mutation. mdm2 protein may play an important role in the pathogenesis of gastric carcinoma through suppressing the function of wild type p53 protein. The infection of EBV relates to the abnomal expression of p53 protein, but not to the abnomal expression of mdm2 protein and p53 gene mutation in gastric carcinoma

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Cloning and expression of gastric cancer related gene GCRG224 in E.coli

AIM: To express gastric cancer related gene GCRG224 by using thioredoxin fusion expression system.

METHODS: GCRG224 cDNA with complete open reading frame was amplified by PCR from plasmid pGEM-T, and then cloned into thioredoxin fusion expression vector pET102/D-TOPO. The recombinant plasmid was further transformed into E.coli BL21 strain. After induction with IPTG, thioredoxin-GCRG224 fusion protein was expressed in E.coli.

RESULTS: SDS-PAGE analysis showed the thioredoxin-GCRG224 fusion protein with a relative molecule mass of 16 800 was highly expressed. The thin layer gel scanning analysis showed that the yield of GCRG224 fusion protein was 22.3% of the total bacterial protein.

CONCLUSION: The GCRG224 recombinant fusion protein is successfully expressed in E.coli.

Expression of apoptosis-related proteins and proliferating cell nuclear antigen during stomach canceration

AIM: To study the role of apoptosis-related gene p53, Bcl-2, and proliferating cell nuclear antigen (PCNA) in gastric cancinogenesis.

METHODS: Immunohistochemical method (LSAB) was used to assess p53, Bcl-2, PCNA expression in specimens of 52 patients with gastric cancer and precancerous lesions.

RESULTS: In the patients with intestinal metaplasia, dysplasia and gastric cancer, the expression rates of p53 were 27.8%, 38.2% and 57.7% respectively. The expression rates of Bcl-2 were 33.3%, 50.0% and 65.4%, and PCNA indexes were 41.4±13.0, 47.9±8.9 and 53.0±11.9 respectively. In patients with intestinal-type carcinoma, p53 and Bcl-2 remained expressed in all precancerous tissues after development into cancer. In diffuse-type carcinoma, the positive Bcl-2 expression became negative in one patient. PCNA LI markedly increased from precancerous lesions to cancer, and a significant difference was observed in intestinal-type carcinoma (P < 0.001).

CONCLUSION: The expression of p53 and Bcl-2 significantly influences the development of intestinal-type gastric carcinoma, and the proliferating activity of the cancer cells gradually increase.

Microsatellite instability in dysplasia mucosa and gastric cancer

AIM: Gastric mucosa dysplasia has been regarded as a precancerous lesion of the stomach. Abnormal gene alterations in the mucosa dysplasia of the stomach, which may lead to cell transformation, are probably of great importance in the development of gastric cancer (GC). Microsatellite instability (MSI) is a good marker of genome instability. Investigation of MSI in the cancer and precancerous lesion of the stomach will help us to search into the carcinogenesis of stomach and the potential role of MSI in the development of gastric cancer.

METHODS: Silver staining single strand conformation polymorphis-polymerease chain reaction (PCR-SSCP) was used to screen MSI markers at 5 loci in formalin-fixed,paraffin-embeded tissues of GC (n = 30), dysplasia (n = 30) and corresponding normal gastric tissues.

RESULTS: The abnormal shifting of the single-strand DNA was identified in 7 (23.3%) out of GC, in 9 (30%) out of dysplasia samples respectively. Three (10%) tumors and two (6.7%) dysplasia displayed a high-level of MSI (two or more loci altered). Low-level MSI (one loci altered) was detected in 13.3% of the tumors and in 23.3% dysplasia samples. GC with MSI was associated with distal location of the tumors (P = 0.044). No association was detected between MSI and the grade of dysplasia.

CONCLUSION: The accumulation of MSI in the dysplasia of gastric mucosa may be an early molecular event in the development of gastric cancer. It contributes probably to the multistep gastric carcinogenesis.

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Acute and chronic effects of alcohol exposure on skeletal muscle c-myc, p53, and Bcl-2 mRNA expression

Skeletal muscle atrophy is a common feature in alcoholism that affects up to two-thirds of alcohol misusers, and women appear to be particularly susceptible. There is also some evidence to suggest that malnutrition exacerbates the effects of alcohol on muscle. However, the mechanisms responsible for the myopathy remain elusive, and some studies suggest that acetaldehyde, rather than alcohol, is the principal pathogenic perturbant. Previous reports on rats dosed acutely with ethanol (<24 h) have suggested that increased proto-oncogene expression (i.e., c-myc) may be a causative process, possibly via activating preapoptotic or transcriptional pathways. We hypothesized that 1) increases in c-myc mRNA levels also occur in muscle exposed chronically to alcohol, 2) muscle of female rats is more sensitive than that from male rats, 3) raising acetaldehyde will also increase c-myc, 4) prior starvation will cause further increases in c-myc mRNA expression in response to ethanol, and 5) other genes involved in apoptosis (i.e., p53 and Bcl-2) would also be affected by alcohol. To test this, we measured c-myc mRNA levels in skeletal muscle of rats dosed either chronically (6-7 wk; ethanol as 35% of total dietary energy) or acutely (2.5 h; ethanol as 75 mmol/kg body wt ip) with ethanol. All experiments were carried out in male Wistar rats (approximately 0.1-0.15 kg body wt) except the study that examined gender susceptibility in male and female rats. At the end of the studies, rats were killed, and c-myc, p53, and Bcl-2 mRNA was analyzed in skeletal muscle by RT-PCR with an endogenous internal standard, GAPDH. The results showed that 1) in male rats fed ethanol chronically, there were no increases in c-myc mRNA; 2) increases, however, occurred in c-myc mRNA in muscle from female rats fed ethanol chronically; 3) raising endogenous acetaldehyde with cyanamide increased c-myc mRNA in acute studies; 4) starvation per se increased c-myc mRNA levels and at 1 day potentiated the acute effects of ethanol, indicative of a sensitization response; 5) the only effect seen with p53 mRNA levels was a decrease in muscle of rats starved for 1 day compared with fed rats, and there was no statistically significant effect on Bcl-2 mRNA in any of the experimental conditions. The increases in c-myc may well represent a preapoptotic effect, or even a nonspecific cellular stress response to alcohol and/or acetaldehyde. These data are important in our understanding of a common muscle pathology induced by alcohol.

Gene therapy for gastric cancer: A review

Gastric cancer is common in China, and its early diagnosis and treatment are difficult. In recent years great progress has been achieved in gene therapy, and a wide array of gene therapy systems for gastric cancer has been investigated. The present article deals with the general principles of gene therapy and then focuses on how these principles may be applied to gastric cancer.

Nerve growth factor-induced glutamate release is via p75 receptor, ceramide, and Ca(2+) from ryanodine receptor in developing cerebellar neurons

Very little is known about the contribution of a low affinity neurotrophin receptor, p75, to neurotransmitter release. Here we show that nerve growth factor (NGF) induced a rapid release of glutamate and an increase of Ca2+ in cerebellar neurons through a p75-dependent pathway. The NGF-induced release occurred even in the presence of the Trk inhibitor K252a. The release caused by NGF but not brain-derived neurotrophic factor was enhanced in neurons overexpressing p75. Further, after transfection of p75-small interfering RNA, which down-regulated the endogenous p75 expression, the NGF-induced release was inhibited, suggesting that the NGF-induced glutamate release was through p75. We found that the NGF-increased Ca2+ was derived from the ryanodine-sensitive Ca2+ receptor and that the NGF-increased Ca2+ was essential for the NGF-induced glutamate release. Furthermore, scyphostatin, a sphingomyelinase inhibitor, blocked the NGF-dependent Ca2+ increase and glutamate release, suggesting that a ceramide produced by sphingomyelinase was required for the NGF-stimulated Ca2+ increase and glutamate release. This action of NGF only occurred in developing neurons whereas the brain-derived neurotrophic factor-mediated Ca2+ increase and glutamate release was observed at the mature neuronal stage. Thus, we demonstrate that NGF-mediated neurotransmitter release via the p75-dependent pathway has an important role in developing neurons.