EXPRESSION OF GALECTIN-3 IN GASTRIC CARCINOMA AND ITS SIGNIFICANCE

Objective: To study the expression of Galectin-3 in gastric cancerous tissues and the relationship between Galectin-3 expression and biological behave of gastric carcinoma. Methods: S-P immunohistochemistry method was used to examine Galectin-3 expression in 64 primary gastric cancerous tissues and 10 normal gastric mucosa as control. The expression of Galectin-3 was examined by HPIAS- 2000 image analysis software. Results: Positive Gaiectin-3 expression was observed in 85.9% of the gastric cancer cases. In gastric cancerous tissues, about 46% of cases showed strong nuclear immunoreactivity. The degree of enhancement of immunoreactivity was different in various histopathological subtypes in cancerous tissues. The readings of average absorbency of Galectin-3 in well, moderate and poorly differentiated adenocarcinoma tissues were 0.17130.02147, 0.18730.0313 and 0.25380.1216 respectively. A stronger expression of Galectin-3 in cancerous tissues was observed. When Galectin-3 expression in gastric cancerous tissues was compared with that in normal gastric tissues, there was a significant difference (P<0.001). Conclusion: A significantly stronger expression of Galectin-3 in gastric cancerous tissues was observed. Galectin-3 might be a useful tumor marker for gastric carcinomas with respects to tumor metastasis, proliferation, cancer progression, and tumor cell adhesion.

A STUDY OF ENDOSCOPIC TREATMENT OF ADVANCED ESOPHAGEAL AND GASTRIC CARCINOMA

Objective: To investigate the effect of endoscopic treatment on advanced esophageal and gastric carcinoma. Methods: Twenty advanced gastric cancer patients and 25 advanced esophageal cancer patients, who had recurrence after operation and radiotherapy were managed by endoscopic treatment. Results: 10 cases were treated to stop bleeding only, 35 cases were treated by microwave, dilation and local chemotherapy. The successful rate of hemostasis was about 67%, the remission rate of digestive obstruction was about 100% after dilation, 83% of the recurrence lesions were relieved by endoscopic chemo therapy. Conclusion: Endoscope treatment has certain therapeutic efficiency for the recurrence of advanced esophageal and gastric cancer.

INDUCTION OF APOPTOSIS IN HUMAN GASTRIC CARCINOMA CELL LINE MGC-803 BY MONOCLONAL ANTIBODY PD4

Objective: To study the effect of McAb PD4 on the cell cycle and on cell injury in the gastric carcinoma cell line, MGC 803. Methods: The effects of McAb PD4 on cell proliferation cycle and cell injury of MGC 803 cells were examined by flow cytometry analysis, DNA electrophoresis and terminal deoxynucle otidyl trans ferase assay. Fas antigen was investigated by ELISA. Results: McAb PD4 inhibited tumor growth of MGC 803 cells in nude mice by inducing apoptosis. Conclusion: P40 is a tumor associated antigen distinct from the Fas antigen. Molecular cloning of P40 will define the pathway and mechanism of apoptosis induced by McAb PD4. Induction of apoptosis by McAb PD4 may be a useful therapeutic approach in treating cancer.

MiR-204-3p overexpression inhibits gastric carcinoma cell proliferation by inhibiting the MAPK pathway and RIP1/MLK1 necroptosis pathway to promote apoptosis

BACKGROUND Gastric carcinoma(GC)is the third most frequent cause of cancer-related death,highlighting the pressing need for novel clinical treatment options.In this regard,microRNAs(miRNAs)have emerged as a promising therapeutic strategy.Studies have shown that miRNAs can regulate related signaling pathways,acting as tumor suppressors or tumor promoters.AIM To explore the effect of miR-204-3p on GC cells.METHODS We measured the expression levels of miR-204-3p in GC cells using quantitative real-time polymerase chain reaction,followed by the delivery of miR-204-3p overexpression and miR-204-3p knockdown vectors into GC cells.CCK-8 was used to detect the effect of miR-204-3p on the proliferation of GC cells,and the colony formation ability of GC cells was detected by the clonal formation assay.The effects of miR-204-3p on GC cell cycle and apoptosis were detected by flow cytometry.The BABL/c nude mouse subcutaneous tumor model using MKN-45 cells was constructed to verify the effect of miR-204-3p on the tumorigenicity of GC cells.Furthermore,the study investigated the effects of miR-204-3p on various proteins related to the MAPK signaling pathway,necroptosis signaling pathway and apoptosis signaling pathway on GC cells using Western blot techniques.RESULTS Firstly,we found that the expression of miR-204-3p in GC was low.When treated with the lentivirus overexpression vector,miR-204-3p expression significantly increased,but the lentivirus knockout vector had no significant effect on miR-204-3p.In vitro experiments confirmed that miR-204-3p overexpression inhibited GC cell viability,promoted cell apoptosis,blocked the cell cycle,and inhibited colony formation ability.In vivo animal experiments confirmed that miR-204-3p overexpression inhibited subcutaneous tumorigenesis ability in BABL/c nude mice.Simultaneously,our results verified that miR-204-3p overexpression can inhibit GC cell proliferation by inhibiting protein expression levels of KRAS and p-ERK1/2 in the MAPK pathway,as well as inhibiting protein expression levels of p-RIP1 and p-MLK1 in the necroptosis pathway to promote the BCL-2/BAX/Caspase-3 apoptosis pathway.CONCLUSION MiR-204-3p overexpression inhibited GC cell proliferation by inhibiting the MAPK pathway and necroptosis pathway to promote apoptosis of GC cells.Thus,miR-204-3p may represent a new potential therapeutic target for GC.

Quantitative parameters in novel spectral computed tomography:Assessment of Ki-67 expression in patients with gastric adenocarcinoma

BACKGROUND The level of Ki-67 expression has served as a prognostic factor in gastric cancer.The quantitative parameters based on the novel dual-layer spectral detector computed tomography(DLSDCT)in discriminating the Ki-67 expression status are unclear.AIM To investigate the diagnostic ability of DLSDCT-derived parameters for Ki-67 expression status in gastric carcinoma(GC).METHODS Dual-phase enhanced abdominal DLSDCT was performed preoperatively in 108 patients with gastric adenocarcinoma.Primary tumor monoenergetic CT attenuation value at 40-100 kilo electron volt(kev),the slope of the spectral curve(λ_(HU)),iodine concentration(IC),normalized IC(nIC),effective atomic number(Z^(eff))and normalized Z^(eff)(nZ^(eff))in the arterial phase(AP)and venous phase(VP)were retrospectively compared between patients with low and high Ki-67 expression in gastric adenocarcinoma.Spearman’s correlation coefficient was used to analyze the association between the above parameters and Ki-67 expression status.Receiver operating characteristic(ROC)curve analysis was performed to compare the diagnostic efficacy of the statistically significant parameters between two groups.RESULTS Thirty-seven and 71 patients were classified as having low and high Ki-67 expression,respectively.CT_(40 kev-VP),CT_(70 kev-VP),CT_(100 kev-VP),and Z^(eff)-related parameters were significantly higher,but IC-related parameters were lower in the group with low Ki-67 expression status than the group with high Ki-67 expression status,and other analyzed parameters showed no statistical difference between the two groups.Spearman’s correlation analysis showed that CT_(40 kev-VP),CT_(70 kev-VP),CT_(100 kev-VP),Z^(eff),and n Z^(eff) exhibited a negative correlation with Ki-67 status,whereas IC and nIC had positive correlation with Ki-67 status.The ROC analysis demonstrated that the multi-variable model of spectral parameters performed well in identifying the Ki-67 status[area under the curve(AUC)=0.967;sensitivity 95.77%;specificity 91.89%)].Nevertheless,the differentiating capabilities of singlevariable model were moderate(AUC value 0.630-0.835).In addition,the nZ_(VP)^(eff) and nIC_(VP)(AUC 0.835 and 0.805)showed better performance than CT_(40 kev-VP),CT_(70 kev-VP) and CT_(100 kev-VP)(AUC 0.630,0.631 and 0.662)in discriminating the Ki-67 status.CONCLUSION Quantitative spectral parameters are feasible to distinguish low and high Ki-67 expression in gastric adenocarcinoma.Z^(eff) and IC may be useful parameters for evaluating the Ki-67 expression.

Deltonin enhances gastric carcinoma cell apoptosis and chemosensitivity to cisplatin via inhibiting PI3K/AKT/mTOR and MAPK signaling

BACKGROUND As an active ingredient derived from Dioscorea zingiberensis C.H.Wright,deltonin has been reported to show anti-cancer effects in a variety of malignancies.AIM To investigate the role and mechanism of action of deltonin in promoting gastric carcinoma(GC)cell apoptosis and chemosensitivity to cisplatin.METHODS The GC cell lines AGS,HGC-27,and MKN-45 were treated with deltonin and then subjected to flow cytometry and 3-(4,5-dimethylthiazol-2-yl)-3,5-diphenyltet-razolium bromide assays for cell apoptosis and viability determination.Western blot analysis was conducted to examine alterations in the expression of apoptosis-related proteins(Bax,Bid,Bad,and Fas),DNA repair-associated proteins(Rad51 and MDM2),and phosphatidylinositol 3-kinase/protein kinase B/mammalian target of the rapamycin(PI3K/AKT/mTOR)and p38-mitogen-activated protein kinase(MAPK)axis proteins.Additionally,the influence of deltonin on GC cell chemosensitivity to cisplatin was evaluated both in vitro and in vivo.RESULTS Deltonin treatment weakened viability,enhanced apoptosis,and dampened DNA repair in GC cell lines in a dose-dependent pattern.Furthermore,deltonin mitigated PI3K,AKT,mTOR,and p38-MAPK phosphorylation.HS-173,an inhibitor of PI3K,attenuated GC cell viability and abolished deltonin inhibition of GC cell viability and PI3K/AKT/mTOR and p38-MAPK pathway activation.Deltonin also promoted the chemosensitivity of GC cells to cisplatin via repressing GC cell proliferation and growth and accelerating apoptosis.CONCLUSION Deltonin can boost the chemosensitivity of GC cells to cisplatin via inactivating p38-MAPK and PI3K/AKT/mTOR signaling.

Appraisal of gastric stump carcinoma and current state of affairs

Gastric stump carcinoma,also known as remnant gastric carcinoma,is a malignancy arising in the remnant stomach following gastrectomy for a benign or malignant condition.Enterogastric reflux and preexisting risk factors in a patient with gastric cancer are the major contributors to the development of gastric stump carcinoma.The occurrence of gastric stump carcinoma is time-dependent and seen earlier in patients operated on for malignant rather than benign diseases.The tumor location is predominantly at the anastomotic site towards the stomach.However,it can occur anywhere in the remnant stomach.The pattern of lymph node involvement and the type of surgery required is distinctly different compared to primary gastric cancer.Gastric stump carcinoma is traditionally considered a malignancy with a dismal outcome.However,recent advances in diagnostic and therapeutic strategies have improved outcomes.Recent advances in molecular profiling of gastric stump carcinoma have identified distinct molecular subtypes,thereby providing novel therapeutic targets.Also,reports of gastric stump carcinoma following pancreatoduodenectomy and bariatric surgery highlight the need for more research to standardize the diagnosis,staging,and treatment of these tumors.The present review aims to provide an overview of gastric stump carcinoma highlighting the differences in clinicopathological profile and management compared to primary gastric carcinoma.

Update on diagnosis and treatment of early signet-ring cell gastric carcinoma: A literature review

Gastric signet-ring cell gastric carcinoma(GSRC)is an unfavorable subtype of gastric cancer(GC)that presents with greater invasiveness and poorer prognosis in advanced stage than other types of GC.However,GSRC in early stage is often considered an indicator of less lymph node metastasis and more satisfying clinical outcome compared to poorly differentiated GC.Therefore,the detection and diagnosis of GSRC at early stage undoubtedly play a crucial role in the management of GSRC patients.In recent years,technological advancement in endoscopy including narrow-band imaging and magnifying endoscopy has significantly improved the accuracy and sensitivity of the diagnosis under endoscopy for GSRC patients.Researches have confirmed that early stage GSRC that meets the expanded criteria of endoscopic resection showed comparable outcomes to surgery after receiving endoscopic submucosal dissection(ESD),indicating that ESD could be considered standard treatment for GSRC after thorough selection and evaluation.This article summarizes the current knowledge and updates pertaining to the endoscopic diagnosis and treatment of early stage signet-ring cell gastric carcinoma.

Gastric adenosquamous carcinoma with an elevated serum level of alpha-fetoprotein:A case report

BACKGROUND Gastric adenosquamous carcinoma(ASC)is rare and characterized by coexisting of adenocarcinoma andsquamous carcinoma within the same tumor.We present a female patient with gastric ASC who had an elevated serum level of alpha-fetopro-tein(AFP),which decreased to normal levels after a laparoscopic distant radical gastrectomy in a short period.The clinicopathological features in AFP-producing gastric cancer(GC)are discussed,as well as potentially available prognostic predi-ctors.CASE SUMMARY A 50-year-old woman presented to our department with a chief complain of a 6-mo history of bloating.She had no basic diseases including heart diseases and respiratory diseases,and she also denied any prior history of dysphagia,hematemesis,melena,rectal bleeding,hematochezia,or unintentional weight loss.Based on her symptoms,an esophagogastroduodenoscopy was performed,showing an annular cavity lesion 3 cm from the pylorus with a diameter of 6 cm.A biopsy of the lesion showed gastric ASC,whereas the pylorus biopsy showed normal mucosa.The patient further received an enhanced computed tomography scan which demonstrated an invasive lesion close to the pylorus with a still clear margin of the tumor to peripheral organs such as the pancreas and liver.Scattered lymph nodes were visible around,whereas no sign of liver metastasis was discovered.Serum tumor markers including carcinoembryonic antigen(CEA),cancer antigen 199(CA199),CA724,CA125,and CA242 were all normal,while the level of serum AFP increased to 172 ng/mL.A laparoscopic distant radical gastrectomy was performed after exclusion of surgical contraindications.Postoperative pathology results showed that the tumor displayed an ulcerated ASC phenotype(90%of medium to highly-differentiated squamous cell carcinoma,10%of poorly differentiated adenocarcinoma.Surprisingly,the serum level of AFP decreased to normal level on post operation day 5.The tumor cells were positive for CK5/6,p63,and CEA,and negative for AFP and Epstein-Barr encoding region.CONCLUSION We presented a rare case of gastric ASC with elevated serum AFP level,which may be new subtype of AFP-producing GC.Follow-up detection of serum AFP might be a useful tool to predict patient prognosis.

Genomic characterization of peritoneal lavage cytology-positive gastric cancer

Objective: Positive peritoneal lavege cytology(CY1) gastric cancer is featured by dismal prognosis, with high risks of peritoneal metastasis. However, there is a lack of evidence on pathogenic mechanism and signature of CY1and there is a continuous debate on CY1 therapy. Therefore, exploring the mechanism of CY1 is crucial for treatment strategies and targets for CY1 gastric cancer.Methods: In order to figure out specific driver genes and marker genes of CY1 gastric cancer, and ultimately offer clues for potential marker and risk assessment of CY1, 17 cytology-positive gastric cancer patients and 31matched cytology-negative gastric cancer patients were enrolled in this study. The enrollment criteria were based on the results of diagnostic laparoscopy staging and cytology inspection of exfoliated cells. Whole exome sequencing was then performed on tumor samples to evaluate genomic characterization of cytology-positive gastric cancer.Results: Least absolute shrinkage and selection operator(LASSO) algorithm identified 43 cytology-positive marker genes, while Mut Sig CV identified 42 cytology-positive specific driver genes. CD3G and CDKL2 were both driver and marker genes of CY1. Regarding mutational signatures, driver gene mutation and tumor subclone architecture, no significant differences were observed between CY1 and negative peritoneal lavege cytology(CY0).Conclusions: There might not be distinct differences between CY1 and CY0, and CY1 might represent the progression of CY0 gastric cancer rather than constituting an independent subtype. This genomic analysis will thus provide key molecular insights into CY1, which may have a direct effect on treatment recommendations for CY1and CY0 patients, and provides opportunities for genome-guided clinical trials and drug development.

Caveolin-1,E-cadherin and β-catenin in Gastric Carcinoma,Precancerous Tissues and Chronic Non-atrophic Gastritis

Objective： To investigate the expressions of caveolin-1, E-cadherin and β-catenin in gastric carcinoma, precancerous gastric and chronic non-atrophic gastritis tissues, and evaluate the correlation of these expressions with the development of gastric cancer. Methods： The expressions of caveolin-1, E-cadherin and β-catenin were detected by biotin-streptavidinperoxidase （SP） immunohistochemistry on 58 gastric cancer tissues, 40 precancerous gastric tissues and 42 chronic non-atrophic gastritis tissues. The correlation between the expressions of caveolin-1, E-cadherin and β-catenin, and the clinicopathologic parameters of gastric cancer was analyzed retrospectively. Results： The positive rates of caveolin-1 and E-cadherin expressions in gastric carcinoma were significantly lower than precancerous gastric and chronic non-atrophic gastritis tissues （P〈0.01）. An abnormal rate of β-catenin expression in gastric carcinoma was higher than precancerous gastric and chronic non-atrophic gastritis tissues （P〈0.01）. Moreover, low expressions of caveolin-1, E-cadherin and β-catenin correlated with tumor size, depth of invasion, lymph node metastasis and TNM stage （P〈0.05）. The positive rates of caveolin-1 and E-cadherin expressions decreased （P〈0.01）, while an abnormal rate of β-catenin expression increased inversely, with the degree of atypical hyperplasia （P〈0.01）. Caveolin-1 expression correlated positively with E-cadherin （r=0.41, P〈0.05）. Caveolin-1 （r=-0.36, P〈0.05） and E-cadherin （r=-0.45, P〈0.05） expressions negatively correlated with abnormal β-catenin expression. Conclusion： These results suggested that dysregulated expressions of caveolin-1, E-cadherin and β-catenin correlated with the development of gastric cancer and its biological behavior.

Decline of serum CA724 as a probable predictive factor for tumor response during chemotherapy of advanced gastric carcinoma

Objective： To evaluate the predictive value of decline in the serum level of carbohydrate antigen 724 （CA724） on tumor response during the chemotherapy in patients with advanced gastric carcinoma （GC）. Methods= The serum CA724 level was determined by electrochemiluminescence immunoassay, while the objective response rate （eRR） was assessed according to response evaluation criteria in solid tumors （RECIST）. The association of the changes of serum concentration of CA724 with eRR was analyzed. Results： The eRR in CA724 （pretreatment serum level） high and low groups was 32.3% （20/62） and 52.8% （19/36）, respectively （P=0.045）. The relationship between the reduction of CA724 and the eRR was statistically significant （P=0.044）. Receiver operating characteristic （ROC） curve established the best cutoff value of the decrease ratio of CA724 as 20.5%. Conclusions： CA724 decline seems to indicate chemotherapy efficacy in patients with advanced GC, and an average drop of 20.5% in serum CA724 appears to predict the sensitivity to chemotherapy.

Methylation of GATA-4 and GATA-5 and development of sporadic gastric carcinomas

AIM:To understand the implication of GATA-4 and GATA-5 methylation in gastric carcinogenesis.METHODS: Methylation status of GATA-4 and GATA-5 CpG islands in human gastric mucosa samples, including normal gastric biopsies from 45 outpatients, gastric dysplasia [low-grade gastric intraepithelial neoplasia (GIN), n = 30; indefinite, n = 77], and 80 paired spo- radic gastric carcinomas (SGC) as well as the adjacent non-neoplastic gastric tissues was analyzed by methylation specific polymerase chain reaction (MSP) and confirmed by denatured high performance liquid chromatography (DHPLC). Immunohistochemical staining was used to detect protein expression. The correlation between GATA-4 and GATA-5 methylation and clinicopathological characteristics of patients including Helicobacter pylori (H. pylori) infection was analyzed.RESULTS:GATA-4 and GATA-5 methylation was frequently observed in SGCs (53.8% and 61.3%, respectively) and their corresponding normal tissues (41.3% and 46.3%) by MSP. The result of MSP was consistent with that of DHPLC. Loss of both GATA-4 and GATA-5 proteins was associated with their methylation in SGCs (P = 0.01). Moreover, a high frequency of GATA-4 and GATA-5 methylation was found in both gastric low-grade GIN (57.1% and 69.0%) and indefinite for dysplasia (42.9% and 46.7%), respectively. However, GATA-4 and GATA-5 methylation was detected only in 4/32 (12.5%) and 3/39 (7.7%) of normal gastric biopsies. GATA-4 methylation in both normal gastric mucosa and low-grade GIN was also significantly associated with H. pylori infection (P=0.023 and 0.027, two-sides).CONCLUSION: Epigenetic inactivation of GATA-4 (and GATA-5) by methylation of CpG islands is an early freuent event during gastric carcinogenesis and is significantly correlated with H. pylori infection.

Clinical significance of Fas and FasL protein expression in gastric carcinoma and local lymph node tissues

AIM:To investigate the relation of Fas and Fas ligand (FasL) protein expression with carcinogenesis and metastasis of gastric carcinoma.METHODS: Immunohistochemistry was used to detect Fas and FasL protein expression in 64 gastric carcinoma tissue samples and 20 normal gastric tissue samples. Relation between FasL and Fas expression, age and gender of gastric cancer patients, and pathological subtype and lymph node metastasis of gastric cancer was analyzed.RESULTS: The Fas expression level was significantly higher in normal gastric tissue samples than in gastric carcinoma tissue samples (85.0% vs 25.0%, P<0.001), while the FasL expression level was signif icantly lower in normal gastric tissue samples than in gastric carcinoma tissue samples (30.0% vs 81.3%, P<0.001). The Fas expression level was significantly higher in invasive lymph nodes than in non-invasive lymph nodes (82.9% vs 56.5%, P<0.003) and in well-differentiated gastric carcinoma tissue samples than in poorly-differentiated gastric carcinoma tissue samples (50.0% vs 18.0%, P=0.015). The FasL expression level was significantly lower in well-differentiated gastric carcinoma tissue samples than in poorly-differentiated gastric carcinoma tissue samples (42.9% vs 84.0%, P=0.021). The Fas and FasL expression levels (25.0% and 81.3%) were signif icantly different in gastric carcinoma tissue samples (P<0.001), but had a non-linear correlation (P=0.575).CONCLUSION: Abnormal Fas and FasL expressions in gastric carcinoma and lymph node tissues are involved in carcinogenesis and metastasis of gastric cancer.

Clinicopathologic characteristics of gastric carcinoma in elderly patients: A comparison with young patients

AIM:To examine the clinicopathologic features of elderly patients with gastric carcinoma and to investigate the relationship between prognosis and age.METHODS: We reviewed the hospital records of 2 014patients with gastric carcinoma retrospectively to compare the clinicopathologic findings in elderly (age ＞70 years) and young (age ＜36 years) patients during the period from 1986 to 2000 in a tertiary referral center in Gwangju, Korea. Overall survival was the main outcome measure.RESULTS: Of the 2 014 patients, 194 (9.6%) were in the elderly group and 137 (6.8%) were in the young group.The elderly and young patients had similar distributions with respect to depth of invasion, nodal involvement, hepatic metastasis, peritoneal dissemination, tumor stage at the initial diagnosis, and type of surgery. Synchronous multiple carcinomas were found in 14/194 (7.2%) of the elderly group and 4/137 (2.9%) of the young group (P＜0.05). Using the Borrmann classification, type Ⅳ was more frequent in the young patients than in the elderly patients (P＜0.05).Significantly more elderly patients had a well or moderately differentiated histology, and more young patients had a poorly differentiated histology and signet ring cell carcinoma (P＜0.001). The 5-year survival rates of elderly and young patients did not differ statistically (52.8% vs 46.5%,P = 0.5290). Multivariate analysis showed that the histologic type, nodal involvement and operative curability were significant prognostic factors, and age itself was not an independent prognostic factor of survival for elderly gastric carcinoma patients.CONCLUSION: Elderly patients with gastric carcinoma do not have a worse prognosis than young patients. The important prognostic factor is whether the patients undergo a curative resection.

Downregulation of survivin by RNAi inhibits growth of human gastric carcinoma cells

AIM: To investigate the inhibitory effect of a specific small survivin interfering RNA (siRNA) on cell proliferation and the expression of survivin in human gastric carcinoma cell line SGC-7901. METHODS: To knockdown survivin expression, a small interfering RNA targeting against survivin was synthesized and transfected into SGC-7901 cells with lipofectamineTM2000. The downregulation of survivin expression at both mRNA and protein levels were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. Cell proliferation inhibition rates were determined by methyl thiazolyl tetrazolium (MTT) assay. The effect of survivin siRNA on cell cycle distribution and cell apoptosis was determined by flow cytometry (FCM). RESULTS: RNA interference could efficiently suppress the survivin expression in SGC-7901 cells. At 48 h after transfection, the expression inhibition rate was 44.52% at mRNA level detected by RT-PCR and 40.17% at protein level by Western blot analysis. Downregulation of survivin resulted in significant inhibition of tumor cell growth in vitro. The cell proliferation inhibition rates at 24, 48 and 72 h after survivin siRNA and non-siliencing siRNA transfection, were 34.06%, 47.61% and 40.36%, respectively. The apoptosis rate was 3.56% and the number of cells was increased in G0/G1 phase from 38.2% to 88.6%, and decreased in S and G2/M phase at 48 h after transfection. CONCLUSION: Downregulation of survivin results in significant inhibition of tumor growth in vitro. The inhibition of survivin expression can induce apoptosis of SGC-7901 cells. The use of survivin siRNA deserves further investigation as a novel approach to cancer therapy.

Detection of let-7a microRNA by real-time PCR in gastric carcinoma

AIM: To establish an accurate and rapid stem-loop reverse transcriptional real-time PCR (RT-PCR) method to quantify human let-7a miRNA in gastric cancer. METHODS: According to the sequence of let-7a miRNA,the stem-loop reverse transcriptional primer,the primers and quantitative MGB probes of real-time PCR were designed and synthesized. The dynamic range and the sensitivity of quantitative reverse transcriptional real-time PCR were determined. The levels of let-7a miRNA were examined in 32 gastric carcinoma samples by stem-loop RT-PCR method. RESULTS: The dynamic range and sensitivity of the let-7a miRNA quantification scheme were evaluated,the result showed the assay could precisely detect 10 copies of mature let-7a miRNA in as few as 0.05 ng of total RNA of gastric mucosa. The results of specificity analysis showed no fluorescence signal occurred even though 50 ng of human genomic DNA was added to the reverse transcription (RT) reaction. The expression level of let-7a miRNA in gastric tumor tissues was significantly lower compared to normal tissues in 14 samples from 32 patients. CONCLUSION: The stem-loop RT-PCR is a reliable method to detect let-7a miRNA which may play an important role in the development of gastric carcinoma.

Cell cycle arrest and apoptotic cell death in cultured human gastric carcinoma cells mediated by arsenic trioxide

AIM: To investigate the effect of arsenic trioxide on human gastric cancer cell line MKN45 with respect to both cytotoxicity and induction of apoptosis in vitro. METHODS: MKN45 cells were treated with arsenic trioxide(As2O3) at the concentration of 1, 5, and 10 μmol/L,respectively, for three successive days. Cell growth and proliferation were observed by cell counting and trypanblue exclusion. Cytotoxicity of As2O3 was determined by MTT assay. Morphologic changes were studied with light microscopy. Flow cytometry was used to assay cell DNA distribution and apoptotic cells were confirmed with terminal deoxynucleotidyl transferase-mediated dUTP nickend labeling (TUNEL) and DNA electrophoresis.RESULTS: The growth of MKN45 cells was significantlyinhibited by As2O3 which was confirmed by colony-forming assay. After 7 d of culture with various concentrations of As2O3, colony-forming capacity of MKN45 cells decreased with As2O3 increment in comparison with that of control group. The inhibitory rate of colony-formation was 38.5%, 99.1%, and 99.5% when the concentration of As2O3 was1, 5, and 10 iμmol/L in culture medium, respectively. The cell number of a single colony in drug treatment groups was less than that of control group. The cell-killing rate of As2O3 to MKN45 cells was both dose- and timedependent with an IC50 of (11.05±0.25) μmol/L. After incubation in 10 μmol/L As2O3 for 24 h, the cell-killing rate was 27.1%, and it was close to 50% after 48 h. The results showed that As2O3 induced time- and dosedependent apoptosis in MKN45 cells, blocked at G2/M phase. The apoptotic peak (sub-G1 phase) appeared and cell apoptotic rate in MKN45 cells was 18.3-32.5% aftertreatment by 10 μmol/L As2O3 for 48 h. The percentage of G2/M cell of the experimental groups was 2.0-5.0 times than that of the control group. Gel electrophoresis of DNA from cells treated with each concentration of As2O3 for 48 h revealed a 'ladder' pattern, indicating preferential DNA degradation at the internucleosomal, linker DNA sections. TUNEL also demonstrated strand breaks in DNA of MKN45 cells treated with As2O3, while control cellsshowed negative labeling.CONCLUSION: As2O3 can induce apoptosis of human gastric carcinoma cells MKN45, which is the basis of its effectiveness. It shows great potential in the treatment of gastric carcinoma.

Clinicopathologic significance of HER-2/neu protein expression and gene amplification in gastric carcinoma

AIM:To study the HER-2/neu protein expression and gene amplification in gastric carcinoma and their relation.METHODS:One hundred and forty-five formalin-fixed and paraffin-embedded tumor tissue samples from Chinese gastric carcinoma patients were studied with immunohistochemistry(IHC)and fluorescence in situ hybridization(FISH)methods.Clinicopathologic data about all patients were collected.RESULTS:The levels of HER-2 3+,HER-2 2+and HER21+were measurable in 6.9%,8.3%and 17.2%of the samples,respectively.No HER-2 was stained in 67.6% of the samples.FISH showed that HER-2 gene was amplified in 18 samples,10 HER-2 3+samples,5 HER-2 2+samples,and 3 HER-2 1+samples with IHC staining.HER-2 status was not correlated with the sex and age of patients,and tumor size,location or differentiation,but with the depth of invasion,TNM stage,lymph node and distant metastasis as well as histopathological classification of gastric cancer(P<0.05).CONCLUSION:All samples with IHC as HER-2 expression should be analyzed with FISH.Detection of HER-2 gene amplification can assess the malignant biological behaviors and prognosis of gastric cancer.

Relationship between RGS5 expression and differentiation and angiogenesis of gastric carcinoma

AIM:To explore the regulator of G-protein signaling 5 (RGS5) expression in gastric carcinoma and its association with differentiation and microvascular density (MVD).METHODS:Expression of RGS5 and CD34 were examined in 76 cases of gastric carcinoma,including 22 cases with lymph node metastasis and 54 cases without lymph node metastasis determined by immunohistochemistry (IHC).MVD was assessed using CD34 monoclonal antibody.The presence of RGS5 and CD34 was analyzed by IHC using the Envision technique.RESULTS:The RGS5 expression in gastric carcinoma was positively correlated with the differentiation of the tumor (r=0.345,P < 0.001),but not related with age,gender,tumor size,clinical stage and lymph node metastasis (P > 0.05).The average MVD in the group with lymph node metastasis was significantly higher than that in the group without lymph node metastasis (P < 0.05).RGS5 expression was negatively correlated with the average MVD (P < 0.05).CONCLUSION:RGS5 expression level in gastric carcinoma is associated with the differentiation and MVD of the tumor,and may be used as an important parameter for determining the prognosis of gastric carcinoma patients.