miR-106b Promotes Metastasis of Early Gastric Cancer by Targeting ALEX1 in Vitro and in Vivo.

BACKGROUND/AIMS: Aberrant expression of miR-106b is a specific symptom of many solid carcinomas. Overexpression of miR-106b has been observed in gastric cancer. The effect of miR-106b on gastric cancer has been investigated in different cell culture models. However, the effect of miR-106b on metastasis of early gastric cancer (EGC) remains unknown. METHODS: In the study, qRT-PCR, FISH, western blot, luciferase reporter assay, migration and invasion assays, flow cytometry and TUNEL staining were used to investigate the effect of miR-106b on metastasis of EGC. RESULTS: To explore the function of miR-106b in EGC, we investigated the downstream signaling of miR-106b and found that ALEX1 was a direct target of miR-106 in gastric cancer cells. Up-regulation of ALEX1 effectively rescued the cell apoptosis induced by miR-106b inhibitor and promoted the expression levels of phosphorylation of JAK1 and STAT3. Moreover, overexpression of JAK1 reduced the cell apoptosis induced by miR-106b inhibitor and decreased the expression levels of the apoptotic proteins in gastric cancer cells. Furthermore, down-regulation of miR-106b promoted apoptosis of gastric cancer cells via inhibiting JAK1/STAT3 signaling pathway in vitro and in vivo. In addition, GLPG0643, a JAK1 inhibitor, enhanced the inhibitory effect of miR-106b inhibitor on gastric cancer growth in vivo. CONCLUSION: These findings provided a potential therapeutic manner for the treatment of metastasis of EGC in clinic.

Tumor suppressor miR-24 restrains gastric cancer progression by downregulating RegIV.

BACKGROUND: microRNAs are small noncoding RNAs that modulate a variety of cellular processes by regulating multiple targets, which can promote or inhibit the development of malignant behaviors. Accumulating evidence suggests miR-24 plays important roles in human carcinogenesis. However, its precise biological role remains largely elusive. This study examined the role of miR-24 in gastric cancer (GC). METHODS: The expression of miR-24 in GC tissues compared with matched non-tumor tissues and GC cells was detected by qRT-PCR. Synthetic short single or double stranded RNA oligonucleotides and lentiviral vectors were used to regulate miR-24 expression in GC cells to investigate its function in vitro and in vivo. RESULTS: miR-24 was significantly downregulated in GC tissues compared with matched non-tumor tissues and was associated with tumor differentiation. Ectopic expression of miR-24 in SGC-7901 GC cells suppressed cell proliferation, migration and invasion in vitro as well as tumorigenicity in vivo by inducing cell cycle arrest in G0/G1 phase and promoting cell apoptosis. Furthermore, we identified RegIV as a target of miR-24 and demonstrated that miR-24 regulated RegIV expression via binding its 3' untranslated region. CONCLUSIONS: miR-24 functions as a novel tumor suppressor in GC and the anti-oncogenic activity may involve its inhibition of the target gene RegIV. These findings suggest the possibility for miR-24 as a therapeutic target in GC.

Is PET-CT suitable for predicting lymph node status for gastric cancer?

BACKGROUND/AIMS: To verify the value of PET-CT for predicting lymph node status of gastric cancer preoperatively. METHODOLOGY: 78 gastric cancer patients accepted PET-CT preoperatively, the results of lymph node status were compared with the postoperative pathology. CT was used as control. RESULTS: The accuracy of PET-CT and CT in N category was 55.1% vs. 54.4%, respectively. The sensitivity, specificity, accuracy, positive predicting value (PPV), and negative predicting value (NPV) of PET-CT in predicting position of positive lymph node were 31.0%, 97.2%, 61.5%, 92.9%, and 54.7%, respectively. While for CT, were 60.5%, 83.3%, 70.6%, 82.1%, and 62.5%, respectively. For tier 1 lymph node metastasis, the sensitivity, specificity, accuracy, PPV, and NPV of PET-CT were 31.6%, 95.0%, 64.1%, 85.7%, and 59.4%, respectively. While for CT, were 60.0%, 78.8%, 69.1%, 75.0%, and 65.0%, respectively. The sensitivity of CT was significantly better (p = 0.031). For tier 2 or tier 3 lymph node metastasis, the sensitivity, specificity, accuracy, PPV, and NPV of PET-CT were 12.0%, 98.1%, 70.5%, 75.0%, and 70.3%, respectively. While for CT, were 22.7%, 93.5%, 70.6%, 62.5%, and 71.7%, respectively, without significance. CONCLUSIONS: PET-CT is not sensitive enough to predict the regional lymph node status of gastric cancer preoperatively.

Identification of biomarkers for childhood obesity based on expressional correlation and functional similarity.

The aim of the current study was to identify potential biomarkers of childhood obesity, and investigate molecular mechanisms and candidate agents in order to improve therapeutic strategies for childhood obesity. The GSE9624 gene expression profile was downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) in omental adipose tissues were analyzed with limma package by comparing samples from obese and normal control children. Two­way hierarchical clustering was applied using the pheatmap package. The co­expression (CE) analysis was performed using online CoExpress software. Subsequent to functional classification via the GOSim package, the gene network enriched by DEGs was visualized using the Cytoscape package. The codon usage bias of the DEGs was then examined using the CAI program from the European Molecular Biology Open Software Suite. In total, 583 DEGs (273 upregulated genes and 310 downregulated genes) were observed in the omental adipose tissues between samples from obese and normal control children. Hierarchical clustering identified a significant difference between samples from obese and normal control children. Subsequent to CE analysis, 130 DEGs, which were classified into 4 clusters, were selected. The following 3 upregulated and 2 downregulated genes were identified to be significant: Upregulated genes, microtubule­associated protein tau (MAPT), destrin (actin depolymerizing factor) (DSTN) and spectrin, ß, non­erythrocytic 1 (SPTBN1); downregulated genes, Rho/Rac guanine nucleotide exchange factor 2 (ARHGEF2) and spindle and kinetochore associated complex subunit 1 (SKA1). The top 3 amino acids were identified to be glycine, leucine and serine with a high bias. The DEGs MAPT, DSTN, SPTBN1, ARHGEF2 and SKA1 are suggested to be candidate biomarkers for childhood obesity.

G9A promotes gastric cancer metastasis by upregulating ITGB3 in a SET domain-independent manner.

Tumor metastasis is the leading cause of death in patients with advanced gastric cancer (GC). Limited therapeutic regimens are available for this condition, which is associated with a poor prognosis, and the mechanisms underlying tumor metastasis remain unclear. In the present study, increased histone methyltransferase G9A expression in GC tissues correlated with advanced stage and shorter overall survival, and in vitro and in vivo experiments revealed that G9A promoted tumor invasion and metastasis. Moreover, we observed that Reg IV induced G9A via the p-ERK/p-SP1 pathway. SP1 directly binds the G9A promoter and enhances G9A expression, and upregulated G9A then forms a transcriptional activator complex with P300 and GR, thereby promoting ITGB3 expression induced by dexamethasone (DEX) and contributing to GC metastasis. However, the G9A-mediated increase in ITGB3 expression was not dependent on the SET domain and methyltransferase activity of G9A. This study demonstrates that G9A is an independent prognostic marker and promotes metastasis in GC, thus suggesting that it may be a tumor biomarker and potential therapeutic target in GC.

The diagnostic value of PET-CT for peritoneal dissemination of abdominal malignancies.

AIM: To evaluate the diagnostic value of PET-CT for predicting peritoneal metastasis of abdominal malignancies. METHODS: One hundred fifty four (154) cases of malignant tumor, including 141 cases of gastric cancer, 9 cases of colon cancer, 2 cases of ovary cancer, and 2 cases of pseudomyxoma, had accepted PET CT from Nov. 2002 to Jan. 2006. One hundred twenty three (123) had also accepted high speed spiral CT (HSSCT) as control. The results were compared with peritoneal lavage, pathological examination and clinical manifestation. RESULTS: The accuracy of PET-CT for peritoneal metastasis was 87.7%, with sensitivity 72.7%, specificity 93.6%, PPV 82.1% and NPV 89.6%. HSSCT showed an accuracy of 79.7%, sensitivity 47.4%, specificity 94.1%, PPV 78.3%, and NPV 80.0%. PET-CT had significantly better sensitivity than HSSCT (p < 0.05). For gastric cancer patients alone, PET CT had an accuracy of 87.9%, sensitivity 74.4%, specificity 93.1%, PPV 80.6% and NPV 90.5%, significantly better than HSSCT's 78.1, 39.4, 93.8, 72.2, and 79.2% (p < 0.01), respectively. In case of Cy1P0, PET-CT showed a seemingly better sensitivity of 53.3% vs. 13.3% of HSSCT, although not statistically significant because of the number of observations (p = 0.053). And in P1 cases, PET-CT and HSSCT manifested sensitivity of 84.2% vs 63.2%, respectively, without significance (p = 0.141). CONCLUSION: PET-CT is useful in predicting peritoneal metastasis of malignancies.

[The results of surgical treatment for pseudomyxoma peritonei].

The surgical results of 37 patients with pseudomyxoma pertonei are reported. Twenty eight patients received laparotomy and complete cytoreduction (CC-0) could be done in 6 patients. However, 13 patients received incomplete cytoreduction, and 9 patients underwent drainage of ascites and peritoneal washing. The Peritoneal Carcinomatosis Index (PCI) was less than 20 in CC-0 patients. CC-0 patients survived significantly better than patients with residual disease. Accordingly, peritoneal washing to remove free cancer cells should be aimed for complete cytoreduction of the solid mucinous nodules.

REG4 promotes peritoneal metastasis of gastric cancer through GPR37.

Being the major reason of recurrence and death after surgery, peritoneal metastasis of gastric cancer dooms the prognosis of advanced gastric cancer patients. Regenerating islet-derived family, member 4 (REG4) is believed to promote peritoneal metastasis, however, its mechanism is still a moot point at present. In the present study, we show that high expression of REG4 correlates with advanced stage and poor survival prognosis for gastric cancer patients. REG4 overexpression significantly enhances peritoneal metastasis by increasing adhesion ability. Moreover, SP1 is proved to be a transcription factor of REG4 and induce REG4 expression upon TGF-alpha stimulation. Also, G protein-coupled receptor 37 (GPR37) is identified to be in the same complex of REG4, which mediates REG4's signal transduction and promotes peritoneal metastasis of gastric cancer cell. Interestingly, we also discover a positive feedback loop triggered by REG4, amplifying itself through EGFR transactivation, consisting of GPR37, ADAM17, TGF-alpha, EGFR, SP1 and REG4. In conclusion, REG4 promotes peritoneal metastasis of gastric cancer through GPR37 and triggers a positive feedback loop.

Biglycan stimulates VEGF expression in endothelial cells by activating the TLR signaling pathway.

Biglycan (BGN) is an important component of the extracellular matrix (ECM) that is implicated in a variety of human cancers. In our previous study, we reported that BGN was overexpressed in gastric cancer (GC) tissues and promoted cancer metastasis. Moreover, the tubular formation capacity in HUVECs was promoted by stimulation with culture media from BGN-overexpressing GC cells, but the exact underlying mechanism is still unknown. The purpose of this study was to determine the role and molecular mechanism of BGN in VEGF expression in endothelial cells. We found that BGN stimulation of endothelial cells increased the interaction between NF-kB and the HIF-1α promoter, leading to enhanced promoter activity and increased HIF-1α mRNA levels, as well as augmented HIF-1 activity that resulted in VEGF expression. All of this was dependent on the interaction of BGN with its receptors, TLR2 and TLR4. Moreover, we found that BGN enhanced endothelial cell migration and proliferation, as well as tube formation, in a TLR signaling pathway-dependent manner. In addition, endothelial cell-derived VEGF in turn was found to act on GC cells and promotes their migration. The combined findings of our current and previous studies suggest that BGN secreted from GC cells into the tumor stroma promotes GC development, as well as its progression, potentially through the chronic activation of tumor angiogenesis.

Mitochondrial aldehyde dehydrogenase 2 protects gastric mucosa cells against DNA damage caused by oxidative stress.

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is a member of the aldehyde dehydrogenase superfamily and is involved with the metabolic processing of aldehydes. ALDH2 plays a cytoprotective role by removing aldehydes produced during normal metabolism. We examined the cytoprotective role of ALDH2 specifically in gastric mucosa cells. Overexpression of ALDH2 increased the viability of gastric mucosa cells treated with H2O2, while knockdown of ALDH2 had an opposite effect. Moreover, overexpression of ALDH2 protected gastric mucosa cells against oxidative stress-induced apoptosis as determined by flow cytometry, Hoechst 33342, and TUNEL assays. Consistently, ALDH2 knockdown had an opposite effect. Additionally, DNA damage was ameliorated in ALDH2-overexpressing gastric mucosa cells treated with H2O2. We further identified that this cytoprotective role of ALDH2 was mediated by metabolism of 4-hydroxynonenal (4-HNE). Consistently, 4-HNE mimicked the oxidative stress induced by H2O2 in gastric mucosa cells. Treatment with 4-HNE increased levels of DNA damage in ALDH2-knockdown GES-1 cells, while overexpression of ALDH2 decreased 4-HNE-induced DNA damage. These findings suggest that ALDH2 can protect gastric mucosa cells against DNA damage caused by oxidative stress by reducing levels of 4-HNE.

Serum proteomics for gastric cancer.

According to the World Health Organization, 800,000 cancer-related deaths are caused by gastric cancer each year globally, hence making it the second leading cause of cancer-related deaths in the world. Gastric cancer is often either asymptomatic or causing only nonspecific symptoms in its early stages. By the time the symptoms occur, the cancer has usually reached an advanced stage, which is one of the main reasons for its relatively poor prognosis. Therefore, early diagnosis and early treatment are very crucial. The differential analysis of serum protein between cancer patients and healthy controls can be performed using proteomics techniques and can hence be adopted as tumor biomarkers for the early diagnosis of cancer. So far, several serum tumor biomarkers have been identified for gastric cancer. However due to their poor specificity and sensitivity, they have proven to be insufficient for the reliable diagnosis of gastric cancer. Thus, using modern advanced proteomics techniques to find some new and reliable serum tumor biomarkers for earlier and reliable diagnosis of gastric cancer is a must. Nowadays, proteomic-based techniques, such as SELDI and HCLP, are available to discover biomarkers in gastric cancer. Numerous novel serum tumor biomarkers such as SAA, plasminogen and C9c, have been discovered through serological proteomics strategies. This review mainly focuses on the serum proteomics techniques and their application in the research of gastric cancer.

MicroRNA-17/20a inhibits glucocorticoid-induced osteoclast differentiation and function through targeting RANKL expression in osteoblast cells.

Glucocorticoids act on the osteoblasts to up-regulate the expression of RANKL, which is very important in the etiology of glucocorticoid-induced osteoclast differentiation and bone resorption. The mechanisms of this process are still not completely understood. Recent studies have shown that glucocorticoids mediate osteoblast function by decreasing the expression of microRNA-17-92a cluster. Coincidentally, we found that the microRNA-17/20a (microRNA-17, microRNA-20a) seed sequences were also complementary to a sequence conserved in the 3'- untranslated region of RANKL mRNA. Therefore, we hypothesized that glucocorticoids might promote osteoblast-derived RANKL expression by down-regulating microRNA-17/20a, which favors differentiation and function of the osteoclasts. In the present study, Western blot analysis showed that microRNA-17/20a markedly lowered the levels of RANKL protein and attenuated dexamethasone-induced RANKL expression in the osteoblasts. The post-transcriptional repression of RANKL by microRNA-17/20a was further confirmed by the luciferase reporter assay. Furthermore, we found that dexamethasone-induced osteoclast differentiation and function were significantly attenuated in co-culture with osteoblast over-expressed microRNA-17/20a and osteoclast progenitors. These results showed that microRNA-17/20a may play a significant role in glucocorticoid-induced osteoclast differentiation and function by targeting the RANKL expression in osteoblast cells.

Biglycan enhances gastric cancer invasion by activating FAK signaling pathway.

Biglycan (BGN) is an important member of small leucine-rich proteoglycans family, and has been implicated in oncogenesis and development of various human cancer types. Here we report that BGN promotes tumor invasion and metastasis of gastric cancer both in vitro and in vivo. BGN expression is significantly higher in gastric cancer tissues and associated with lymph node metastasis, depth of tumor invasion and TNM stage. BGN enhances gastric cancer cell wound healing, migration and invasion ability as well as the tube formation ability of endothelial cells in vitro. Animal experiments results in vivo are consistent with outcomes in vitro. BGN induces increased phosphorylation of FAK (Tyr576/577, Tyr925 and Tyr397) and Paxillin. These results indicate that BGN is upregulated, and plays an oncogenic role, in gastric cancer metastasis by activating the FAK signaling pathway.

Identification of novel serum biomarkers for gastric cancer by magnetic bead.

Early diagnosis and early treatment is known to improve prognosis for gastric cancer. Magnetic affinity beads can be used to extract peptides from un-fractionated serum samples. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) can detect the presence and the molecular mass of peptides. MALDI-TOF-MS mass spectra of peptides and proteins were generated after WCX CLINPROT bead fractionation of 62 gastric cancer serum samples. The discovery set consisted of 44 samples while the validation set was 18 serum samples. The spectra were analyzed statistically using flexAnalysisTM and Clin-ProtTM bioinformatic software. The six most significant peaks were selected out by ClinProTool software and utilized to train a Supervised Neural Network to identify gastric cancer sera from control sera. The sensitivity and specificity of the model when tested on the validation set were 100% and 75%, respectively. A set of 6 peptides that can be used to distinguish serum from gastric cancer patients with good sensitivity and specificity were identified, and these peptides may be useful biomarkers to distinguish cancer individuals who may benefit from radiologic or endoscopic examination.

[Evaluation of the gastrointestinal decompression after gastrectomy: a prospective randomized controlled trial].

OBJECTIVE: To evaluate the value of using nasogastric tube for patients after gastrectomy. METHODS: One hundred and eight patients undergone gastrectomy were divided randomizely into nasogastric decompression group(n=53) and non-nasogastric decompression group (n=55). Gastrointestinal function and postoperative complications were compared between the two groups. RESULTS: Between nasogastric decompression group and non-nasogastric decompression group, no significant differences in postoperative complications (20.8% vs 23.6%, P=0.719), postoperative time of flatus [(3.2+/-0.9) d vs (3.0+/-0.7) d, P=0.192], recovery time of drinking [(5.9+/-3.4) d vs (5.1+/-1.6) d, P=0.143], eating time of fluid food [(7.8+/-3.6) d vs (6.8+/-1.8) d, P=0.085] and eating time of semi-fluid food [(9.8+/-3.5) d vs (8.8+/-1.9) d, P=0.081] were found. While the recovery time of bowl sound [(1.8+/-0.7) d vs (2.2+/-0.9) d, (P=0.013)] and hospital stay [(10.2+/-2.1) d vs (11.7+/-4.3) d, (P=0.021)] were shorter in non-nasogastric decompression group. CONCLUSION: It is not necessary to use nasogastric decompression for patients after gastrectomy.

[Clinical value of routine haematoxylin-eosin stain in diagnosing submucosal lymphatic vessel infiltration in early gastric cancer].

OBJECTIVE: To evaluate the value of routine haematoxylin-eosin(HE) stain for submucosal lymphatic vessel infiltration in early gastric cancer. METHODS: Four thousand four hundred and twenty early gastric cancer patients underwent D2 operation. Submucosal lymphatic vessel was detected by routine HE stain. The results were compared with pathological lymph node metastasis. RESULTS: In early gastric cancer, the sensitivity, specificity, accuracy, positive predicting value (PPV), and negative predicting value (NPV) of routine HE stain for submucosal lymphatic vessel infiltration were 54.5%, 82.0%, 78.9%, 27.4%, and 93.5% respectively. In early gastric cancer limited in mucosa, these indexes were 14.5%, 98.0%, 95.8%, 15.8%, and 97.8% respectively. In early gastric cancer infiltrated to submucosa, they were 60.3%, 57.8%, 58.3%, 28.1%, and 84.2% respectively. There were significant differences of submucosal lymphatic vessel infiltration with lymph node metastasis (P< 0.001), but no significant difference with survival rate. The 5-year survival rates of submucosal lymphatic vessel infiltration positive and negative group were 84.4% and 87.3%, median survival time was 6998 d and 7237 d, and mean survival time was 6163.9 d and 6042.6 d respectively (P=0.2495). CONCLUSION: The accuracy of routine HE stain is too low, thus it is not suitable for diagnosing submucosal lymphatic vessel infiltration in early gastric cancer.

[Clinical effect of intraoperative peritoneal hyperthermic chemotherapy for advanced gastric cancer].

OBJECTIVE: To investigate the clinical effect of intraoperative peritoneal hyperthermic chemotherapy (IPHC) for advanced gastric cancer (AGC). METHODS: A total of 118 AGC patients with serosal invasion were enrolled in this study from 1998 to 2001. Among these cases, 96 patients without macroscopic peritoneal metastases were selected for prophylactic study, including 42 cases with IPHC and 54 cases without IPHC as control. Other 22 patients with macroscopic peritoneal metastases were selected for therapeutic study, including 10 cases with IPHC and 12 without IPHC. Postoperative survival rate and peritoneal recurrence were compared. RESULTS: For prophylactic study, the 1, 2 and 4 years survival rates were 85.7%, 81.0% and 63.9% respectively in the patients with IPHC,significantly higher than 77.3%, 61.0% and 50.8% in the patients without IPHC. Cox ratio hazard model revealed that IPHC procedure was an independent prognostic factor. More patients in the control group suffered from peritoneal recurrence than those in IPHC group (34.7% vs 10.3%). For therapeutic study,the median survival period of the patients with IPHC was 10 months, higher than 5 months in the patients without IPHC. The overall 1, 2, 4 year survival rates were 76.9%, 69.2%, 55.2% respectively in all cases with IPHC, higher than 66.2%, 49.7%, 41.4% in the cases without IPHC. CONCLUSION: IPHC procedure can improve the prognosis of AGC patients with serosal invasion, reduce the risk for peritoneal recurrence, and is an independent prognostic factor.