Expression And Significance Of MicroRNA-101and Cyclooxygenase-2in Human Gastric Cancer

Background: MicroRNAs (miRNAs) are short single-stranded non-coding RNAsthat influence post-transcriptional gene regulation by affecting mRNA stability and/ortranslational repression of their target mRNAs. Alterations of the expression patternof miRNAs that regulate genes involved in cellular proliferation, differentiation orapoptosis, have been found in different human tumors including gastric cancer,suggesting that they may represent a novel class of oncogenes or tumor suppressorgenes. Previous studies showed that Cyclooxygenase-2(COX-2) is over-expressed ingastric cancer, and could be one of the key molecules that might contribute to thegrowth and invasiveness of gastric cancer cells. It has been reported that miR-101down-regulation is involved in COX-2over-expression in human gastric cancer cellsin animal models.Objective: To investigate the expression of microRNA-101(miRNA-101) andCOX-2in gastric cancer and their relationship with clinicopathologic characteristicsof the patients.Methods:1. Objects: Thirty gastric cancer specimens and matched normal gastric tissuespecimens were obtained surgically from patients.2. Real time quantitative fluorescence PCR(qRT-PCR): Total RNA was extractedfrom30resected gastric cancer specimens and matched normal tissues specimens,according to the manufacturer’s instructions, followed by reverse transcription.qRT-PCR was carried out to exam the relative expression of target genes miRNA-101and COX-2mRNA. The relative expressions of target gene COX-2mRNA were normalized to that of U6. The relative expressions of target geneCOX-2mRNA were normalized to that of glyceraldehydes-3-phosphatedehydrogenase (GAPDH).3. Immunoblotting test: Western blot was carried out to identify the expression ofCOX-2in gastric cancer specimens and matched normal gastric tissue.Results:1. The relative level of miRNA-101in the cancerous tissue was significantly lowerthan those in the normal gastric mucosa.2. The relative level of COX-2mRNA in the cancerous tissue was significantlyhigher than those in the normal gastric mucosa. The expression of miRNA-101wasnegatively correlated with COX-2mRNA in cancer tissues and normal tissues.3. The expression levels of miRNA-101were significantly lower in the patients withstages III-IV or lymph node metastasis than that in those with stages I-II or withoutsuch metastasis.4. COX-2mRNA expression was significantly higher in the patients with stagesIII-IV or lymph node metastasis than that in those with stages I-II or without suchmetastasis.Conclusion： Reduced miRNA-101expression correlated to high levels of COX-2ingastric cancer tissues is closely related to tumor invasion and lymph node metastasis. Background: The specific cyclooxygenase (COX)-2inhibitor have theanti-proliferative and pro-apoptotic effects on gastric cancer cells. There aresomerandomized, double-blind, placebo-controlled trials with COX-2inhibitors(coxibs) showing an increased rate of thrombotic vascular events in patients treatedwith coxibs. Ursolic acid (UA), a natural pentacyclic triterpenoid carboxylic acid, islargely distributed in medical herbs. UA has a wide range of anticancer functionssuch as proapoptosis, antiangiogenesis, antimetastasis and cytotoxicity in stomach,liver, lung and bladder cancers. Our previous study indicated that UA and NS398inhibited the proliferation and induced the apoptosis of COX-2positive gastric cancercell line SGC-7901, along with down-regulating the expression of COX-2. This studyis designed to evaluate the effects of UA and NS398on COX-2negative gastriccancer cell line MGC-803, which is in an attempt to develop potent antitumor agents.Objective: To investigate the effects of UA and COX-2inhibitor NS398on theproliferation of COX-2positive gastric cancer cell line SGC-7901and COX-2negative gastric cancer cell line MGC-803.Methods: SGC-7901cells and MGC-803cells were seeded in RPMI-1640supplemented with10%heat-inactivated fetal calfserum and routinely incubated for24h. After serum-free starvation for24h, the cellswere cultured with either UA at the Final concentration of10,20,40,80μmol/L orNS-398at the final concentration of50,100,200,400μmol/L for12,24and48h respectively. Cell proliferation was determined using methyl thiazolyl tetrazolium(MTT) colorimetric assay.Results: Both UA and NS398significantly inhibited SGC-7901and MGC-803cellproliferation in a dose-and time-dependent manner.Conclusion: Both UA and COX-2inhibitor NS398significantly inhibited cellproliferation of COX-2positive gastric cancer cell line SGC-7901and COX-2negative gastric cancer cell line MGC-803. Background: Nearly all colorectal cancers are thought to arise from adenomatouspolyps. The conclusions from the National Polyp Study strongly support the conceptthat the removal of polyps may prevent the future development of colorectal cancer.With age increasing, there is a higher prevalence of colonic adenomatous polyps inelderly individuals. Argon plasma coagulation(APC), invented by ERBE German, hasbeen introduced to therapy of gastroenterology in1990’s. APC is useful in themanagement of adenomas in gastrointestinal tract, which can reduce surgery.Objects: To evaluate the safety and efficacy of endoscopic argon plasma coagulation(APC) in the management of elderly patients with colorectal polyps.Methods: Colorectal polyps found in electronic enteroscopy were treated with argonplasma generated by ERBE APC (VIO200D) made in German ERBE Company.Results:1. A total of525polyps in258elderly patients were all cured by APC.2.302(57.5%) sessile flat polyps with diameter0.2cm to0.5cm were ablated withAPC，89(17%) semi-pedunculated and pedunculated polyps were resected by high-frequency electrosection, and134sessile (25.5%) polyps with diameter0.6cm to5.0cm were resected after submucosal injection with epinephrine plus methylene bluenormal saline on focal membrane. APC electric coagulation or titanium clip would beemployed if bleeding appeared in partial wounds.3. Minor bleeding occurred in two patients (0.8%), there were no majorcomplications (perforations or bleeding requiring transfusion). 4. With the size of the polyps growing, the incidence of tubulo-villous adenomasincreases, while the incidence of tubular adenomas decreases. Meanwhile, theincidence of moderate-dysplasia adenomas increases, as well as the incidence ofwild-dysplasia adenomas decreases.Conclusion: APC is a well tolerated and effective treatment in elderly patients withcolorectal polyps.