Metastatic clear cell sarcoma of the pancreas: A rare case report.

BACKGROUND: Clear cell sarcoma (CCS) is a rare soft-tissue sarcoma. The most common metastatic sites for CCS are the lungs, bones and brain. CCS is highly invasive and mainly metastasizes to the lung, followed by the bone and brain; however, pancreatic metastasis is relatively rare. CASE SUMMARY: We report on a rare case of CCS with pancreatic metastasis in a 47-year-old man. The patient had a relevant medical history 3 years ago, with abdominal pain as the main clinical manifestation. No abnormalities were observed on physical examination and the tumor was found on abdominal computed tomography. Based on the medical history and postoperative pathology, the patient was diagnosed with CCS with pancreatic metastasis. The patient was successfully treated with surgical interventions, including distal pancreatectomy and splenectomy. CONCLUSION: This report summarizes the available treatment modalities for CCS and the importance of regular postoperative follow-up for patients with CCS.

Pylorus-preserving gastrectomy for early gastric cancer.

Pylorus-preserving gastrectomy (PPG) has been widely accepted as a function-preserving gastrectomy for middle-third early gastric cancer (EGC) with a distal tumor border at least 4 cm proximal to the pylorus. The procedure essentially preserves the function of the pyloric sphincter, which requires to preserve the upper third of the stomach and a pyloric cuff at least 2.5 cm. The suprapyloric and infrapyloric vessels are usually preserved, as are the hepatic and pyloric branches of the vagus nerve. Compared with distal gastrectomy, PPG has significant advantages in preventing dumping syndrome, body weight loss and bile reflux gastritis. The postoperative complications after PPG have reached an acceptable level. PPG can be considered a safe, effective, and superior choice in EGC, and is expected to be extensively performed in the future.

Identification of lncRNA and mRNA regulatory networks associated with gastric cancer progression.

Gastric cancer is a tumor type characterized by lymph node metastasis and the invasion of local tissues. There is thus a critical need to clarify the molecular mechanisms governing gastric cancer onset and progression to guide the treatment of this disease. Long non-coding RNAs and mRNA expression profiles associated with early and local advanced gastric cancer were examined through microarray analyses, with GO and KEGG analyses being employed as a means of exploring the functional roles of those long non-coding RNAs and mRNAs that were differentially expressed in gastric cancer. In total, 1005 and 1831 lncRNAs and mRNAs, respectively, were found to be differentially expressed between early and local advanced gastric cancer. GO and KEGG analyses revealed several pathways and processes that were dysregulated, including the RNA transport, ECM-receptor interaction, and mRNA splicing pathways. In co-expression networks, E2F1, E2F4, and STAT2 were identified as key transcriptional regulators of these processes. Moreover, thrombospondin-2 was confirmed as being expressed at high levels in more advanced gastric cancer by both the GEO and TCGA databases. RNA-sequencing analyses of SGC-790 cells transfected to express thrombospondin-2 further revealed this gene to enhance NF-kB and TNF pathway signaling activity. These results offer insight into gastric cancer-related regulatory networks and suggest thrombospondin-2 to be an important oncogene that drives the progression of this deadly cancer type.

Mechanical intestinal obstruction in underweight, elderly women due to an incarcerated obturator hernia.

BACKGROUND: Obturator hernia is an infrequent pelvic hernia observed in elderly, emaciated and multiparous women. It often presents with nonspecific clinical symptoms, making it difficult to diagnose. METHODS: We conducted a retrospective descriptive study on 11 patients admitted to our hospital for obturator hernia from 2009 to 2020. RESULTS: All the patients were diagnosed with intestinal obstruction due to incarcerated obturator hernia preoperatively. Eight patients underwent laparotomy with low midline incision. Laparoscopic approach was tried on the other three patients with two patients converting to open surgery because of inadequate visualization, and only one patient received laparoscopic repair. Of the 10 patients receiving laparotomy, seven cases received obturator hernia repair with a match and three cases were subjected to bowel resection (two cases intestinal necrosis and one case intestinal perforation). Simple peritoneal closure was performed on the three contaminated cases. One patient died of septic shock and multiple organ failure. CONCLUSION: The emergent computed tomography allow for early and precise diagnosis of incarcerated obturator hernia. Laparotomy with low midline incision is commonly used to manage obturator hernia in an emergency, whereas laproscopic approach may only apply to some selected cases.

Current status of internal hernia after gastrectomy for gastric cancer.

BACKGROUND: Internal hernia is a well-known postoperative complication after Roux-en-Y gastric bypass. However, it has not been considered a recognized complication for gastric cancer. METHODS: We reviewed the literature in the past decade to clarify the current status of internal hernia after gastrectomy including its incidence, high-risk factors, and treatment. RESULTS: The incidence of internal hernia after gastrectomy was found to be between 0.2 and 5.63%, and the median interval time was less than 2 years. High-risk factors include laparoscopic approach, non-closure of all the mesenteric defects, and Roux-en-Y reconstruction. The rate of bowel resection was significantly higher than that of adhesive small bowel obstruction. CONCLUSION: The true incidence of internal hernia after gastrectomy is generally underestimated. Closure of all the mesenteric defects is one of the most effective methods to prevent postoperative internal hernia. Early surgical exploration is necessary when internal hernia is suspected.

Features of CT and EUS in mesenteric plexiform neurofibroma with Neurofibromatosis type I: A case report.

Plexiform neurofibroma(PNF) is a rare benign tumor of the peripheral nerve, belonging to a subtype of neurofibroma. PNF is common in the head, neck and trunk. It is uncommonly observed in the mesentery. We report a case of mesenteric PNF in a 64-year-old man history of neurofibromatosis type I(NF1), which caused abdomen pain. In addition, the computer tomography(CT) and endoscopic ultrasonography(EUS) manifestations of mesenteric PNF were analyzed. The imaging appearance of a mesenteric plexiform neurofibroma is that many low-density (CT) /mixed echo (EUS) soft tissue masses surrounding the superior mesenteric artery, but not surrounding the superior mesenteric vein. Our case adds to the limited literature regarding NF1 presenting with mesenteric PNF. The computer tomography and endoscopic ultrasonography may facilitate confirma diagnosis of mesenteric PNF.

Esophagus two-step-cut overlap method in esophagojejunostomy after laparoscopic gastrectomy.

PURPOSE: Esophagojejunostomy is a challenging step in laparoscopic gastrectomy. Although the overlap method is a safe and feasible approach for esophagojejunostomy, it has several technical limitations. We developed novel modifications for the overlap method to overcome these disadvantages. METHODS: Forty-eight consecutive gastric cancer patients underwent totally laparoscopic total gastrectomy or laparoscopic proximal gastrectomy with double-tract reconstruction at our institution from January 2019 to April 2020 using the overlap method with the following modifications. The esophagus was initially rotated by 90° counterclockwise, followed by transection of two-thirds of the esophageal diameter. The unstapled esophagus was then transected with a harmonic ultrasonic scalpel to enable esophagostomy at the posterior side of the esophagus. A side-to-side esophagojejunostomy was then formed at the posterior side of the esophagus using an endoscopic linear stapler through the right lower trocar. The common entry hole was closed via hand sewing method using V-Loc suture. This procedure was termed "esophagus two-step-cut overlap method." RESULTS: Only one patient suffered from esophagojejunal anastomotic leakage but subsequently recovered after conservative treatment. Patients did not experience anastomotic bleeding or stricture. CONCLUSION: Our modified overlap method provides satisfactory surgical outcomes and overcomes several technical limitations, such as entering the false lumen of the esophagus, unnecessary pollution caused by nasogastric tube, and unintended left crus stapling during anastomosis.

Current status of laparoscopic proximal gastrectomy in proximal gastric cancer: Technical details and oncologic outcomes.

The incidence of proximal gastric cancer has been increasing continuously. This status has prevailed despite the application of laparoscopic proximal gastrectomy as a surgical treatment for early proximal gastric cancer. The widespread adoption and standardization of this surgical procedure as the primary treatment for the abovementioned cancer has been hampered by the lack of consensus on the optimal reconstruction method after proximal gastrectomy. In addition, the oncological safety of proximal gastrectomy for advanced gastric disease remains unclear. We reviewed the English-language literature to clarify the current status of laparoscopic proximal gastrectomy in proximal gastric cancer. Japanese gastric cancer guidelines have suggested three types of reconstructions for proximal gastrectomy, namely, esophagogastrostomy, double-tract reconstruction, and jejunal interposition. Optimal reconstruction methods remain to be determined because of the lack of adequately performed and well-designed randomized controlled trials. The technical complexity and challenging implementation of reconstruction procedures have resulted in several complications with anastomoses. Multicenter randomized controlled trials are necessary to evaluate the various reconstruction methods and the oncological safety of laparoscopic proximal gastrectomy for advanced gastric disease.

Challenges surrounding postoperative adjuvant chemotherapy for T2N0 gastric cancer.

Determining the requirement for adjuvant chemotherapy in patients with stage IB gastric cancer (GC), and particularly for those with stage T2N0 (muscularis propria) disease, remains challenging. Patients with stage II/III disease benefit from postoperative adjuvant therapy; however, the randomized trials examining whether such therapy affords any survival benefit to patients with T2N0 disease are not sufficient. Current evidence suggests that not all patients with T2N0 disease should undergo such treatment, but only those with a high risk. To date, a number of retrospective studies have attempted to identify factors that are predictive of increased risk in an effort to guide adjuvant therapy-related clinical decision making. The National Comprehensive Cancer Network and the Chinese Society of Clinical Oncology have published guidelines regarding factors associated with increased patient risk. As a result, treatment decisions for patients with stage T2N0 disease are currently determined on an individualized basis, in light of risk factors and the potential benefits of treatment. The present review surveyed current evidence related to the treatment of patients with high-risk GC and highlighted the potential avenues for future investigated.

Polydatin Increases Radiosensitivity by Inducing Apoptosis of Stem Cells in Colorectal Cancer.

This study aimed to investigate the radiosensitizing effect of polydatin (PD) on colorectal cancer (CRC) and its underlying mechanism. The C57BL/6 mouse model of CRC was induced by treatment with azoxymethane (AOM)/dextran sodium sulfate (DSS) and then divided into four groups: control, PD alone, IR alone, and combination of PD and IR. Radiation therapy (200 cGy/min, 10Gy) was performed in mice in the experimental groups for once a week with a total of four times. Thirty minutes before IR, mice were intraperitoneally injected with PD at the dose of 25mg/kg. The number and volume of CRC xenografts were calculated. Immunohistochemical staining was performed to detect the expression of Ki67 and cleaved caspase-3 in tumor tissues samples. The effects of PD on proliferation and apoptosis were evaluated in CT26 and HCT116 colon tumor cells. Leucine-rich repeat-containing G-protein coupled receptor 5 positive (Lgr5+) cancer stem cells (CSCs) were sorted from CT26 cells and the effects of PD on their proliferation and apoptosis were observed to elucidate the radiosensitizing mechanism of PD in CRC cells. Combined therapy with PD and IR significantly decreased tumor volume, inhibited proliferation and induced apoptosis of tumor cells in the mouse model of CRC compared to other three groups. Compared to the IR group, in vitro assay showed that PD combined with IR inhibited proliferation and promoted apoptosis of CT26 and HCT116 colon tumor cells as well as Lgr5+ CSCs. However, addition of the bone morphogenetic protein (BMP) type I receptor inhibitor K02288 (6.4nM) dramatically increased proliferation of Lgr5+ CSCs and abolished the cytotoxic effect of PD combined with IR on Lgr5+ CSCs. The in vivo and in vitro experiments demonstrated that IR combined treatment with PD could inhibit proliferation and promote apoptosis of CRC cells and Lgr5+ CSCs, and BMP signaling pathway was involved in the radiosensitizing effect of PD.

Prediction of cancer progression in a group of 73 gastric cancer patients by circulating cell-free DNA.

BACKGROUND: Circulating cell-free DNA (ccf-DNA) in plasma may contain both specific and non-specific of tumor markers. The concentration and integrity of ccf-DNA may be clinical useful for detecting and predicting cancer progression. METHODS: Plasma samples from 40 healthy controls and 73 patients with gastric cancers (two stage 0, 17 stage I, 11 stage II, 33 stage III, and 10 stage IV according to American Joint Committee on Cancer stage) were assessed respectively. qPCR targeting the Alu repeats was performed using two different sets of primers amplifying the long and short segments. DNA integrity was calculated as a ratio of the long to the short fragments of Alu repeats. RESULTS: Plasma DNA concentration was significantly higher in patients with stage III and IV gastric cancers than in healthy controls (p = 0.028 and 0.029 respectively). The receiver operating characteristic (ROC) curve for discriminating patients with stage III and IV gastric cancers from healthy controls had an area under the curve (AUC) of 0.744 (95% CI, 0.64 to 0.85). Circulating cell-free DNA concentration increased within 21 days following surgery and dropped by 3 months after surgery. CONCLUSIONS: Concentration of ccf-DNA is a promising molecular marker for assessing gastric cancer progression. TRIAL REGISTRATION: Current Controlled Trials ChiCTR-DDT-12002848 , 8 October 2012.

Knockdown of long non-coding RNA HOTAIR inhibits proliferation and invasiveness and improves radiosensitivity in colorectal cancer.

Colorectal cancer (CRC) is still one of the most important neoplasias causing human death. Multidisciplinary therapy has won consensus in the management of CRC, of which, radiotherapy occupies an important position. However, radioresistance is still a major obstacle in local control of CRC. Overexpression of long non-coding RNA HOTAIR has been found to correlate with tumorigenesis and poor prognosis in several types of cancer. In the present study, we analyzed HOTAIR expression levels of 53 CRC patients in tumor and adjacent normal tissue by real-time quantitative PCR. Knockdown of HOTAIR by RNA interference was performed to explore its roles in cell proliferation, migration, invasion, apoptosis and radiosensitivity. Results showed that CRC patients had higher HOTAIR expression in tumor tissues compared with adjacent normal tissues. In vitro, downregulation of HOTAIR reduced proliferation, migration and invasiveness while enhanced apoptosis and radio-sensitivity of CRC cells. Taken together, our findings suggest that long non-coding RNA HOTAIR expression is closely associated with tumor invasion and radiosensitivity, indicating the potential role in diagnostics and therapeutics of CRC.

Wound edge protector for prevention of surgical site infection in laparotomy: an updated systematic review and meta-analysis.

BACKGROUND: An updated meta-analysis based on randomized controlled trials (RCTs) was conducted to evaluate the efficacy of wound edge protector (WEP) in the prevention of surgical site infection (SSI) in patients undergoing laparotomies. METHODS: Meta-analysis was conducted using Review Manager 5.2. The pooled risk ratio was estimated with random-effect model. Medline, Embase, the Cochrane library, reference lists and conference proceedings were data sources. Two independent reviewers screened studies for inclusion and data extraction. Eligible trials were RCTs enrolling patients accepting laparotomies to assess the effectiveness of WEP. RESULTS: Eleven RCTs totalling 2344 patients met the inclusion criteria. Six trials (1589 patients) testing the single-ring design WEP did not show a statistically significant reduction in SSI of laparotomy (RR 0.76, 95% CI 0.51-1.12). Pooled analysis of the five trials (755 patients) that tested the effect of dual-ring design WEP on SSI showed a significant reduction (RR 0.29, 95% CI 0.15-0.55). The combined data of the 11 trials favoured the effect of WEP (RR 0.58, 95% CI 0.39-0.87). Analysis adjusted by the degrees of contamination revealed that WEP is effective in reducing the incidence of SSI after laparotomy of contamination incision (RR 0.43, 0.26-0.72) but failed to demonstrate such effect in clean/contaminated and dirty incisions (RR 0.72, 95% CI 0.43-1.21; RR 0.82, 95% CI 0.43-1.55, respectively). CONCLUSIONS: Our exploratory meta-analysis suggests that WEP reduces the incidence of SSI in patients receiving laparotomies, especially in the circumstance of dual-ring WEP and in contaminated incisions. In order to fully assess the effectiveness of WEP, large-scale and well-designed RCTs are still needed in the future.

Effects of 5­fluorouracil and class III phosphoinositide 3­kinase small interfering RNA combination therapy on SGC7901 human gastric cancer cells.

The aim of the present study was to investigate the effects of small interfering RNA­mediated inhibition of Class III phosphoinositide 3­kinase (PI3K) signal transduction on the proliferation, apoptosis and autophagy of SGC7901 gastric cancer cells. The present study also aimed to examine the contribution of autophagic inhibition to the antitumor effects of 5­fluorouracil (5­FU). A PI3K(III)­RNA interference (i)­green fluorescent protein (GFP) recombinant replication adenovirus (AD) and the negative control (NC)­RNAi­GFP control AD were constructed and infected into SGC7901 cells. A methyl thiazolyl tetrazolium assay was used to determine the growth rate of the SGC7901 cells. Immunofluorescent staining was used to detect microtubule­associated protein 1 light chain 3 expression. The mitochondrial membrane potential was measured using the JC­1 fluorescent probe. Autophagic expression was monitored with MDC staining and transmission electron microscopy. The results revealed that following combination treatment of the SGC7901 gastric cancer cells with 5­FU + PI3K(III)­RNAi­AD, the optical density absorbance values at 24, 48 and 72 h were 0.17 ± 1.64, 0.13 ± 4.64 and 0.11 ± 3.56%, respectively, with cell viability inhibition ratios of 45.89 ± 6.67, 72.57 ± 9.48 and 87.51 ± 4.65%, respectively. As compared with the other treatment groups, the inhibition rate in the combined treatment group was significantly higher (P<0.05). The percentages of the cells with green fluorescence in the combined treatment group were 74.4 ± 3.86 (24 h), 82.3 ± 1.84 (48 h) and 92.5 ± 1.1% (72 h), which were larger than those of the other groups. The percentage of cells with green fluorescence became larger, which indicated that the mitochondrion membrane potential had been reduced to a greater extent. MDC staining revealed that the number of autophagic vacuoles in the cells (measured at 24, 48 and 72 h) decreased gradually with time, with more autophagic vacuoles observed in the cells in the control group at 24 h than those in the other treatment groups. Fewest autophagic vacuoles were identified in the combined treatment group. Using a fluorescence microscope, the immune fluorescence expression of microtubule­associated proteins 1A/1B light chain 3A, which is the specific protein of autophagy, in the combined treatment group was observed to be significantly downregulated, as compared with the other groups. As determined by transmission electron microscopic observation of the SGC7901 gastric cancer cells, the degree of autophagy in the combined treatment group was significantly reduced, as compared with that of the other treatment groups. In conclusion, following combined treatment with 5­FU and an inhibitor of class III PI3K signal transduction, the proliferation of SGC7901 cells was significantly suppressed, the mitochondrion membrane potentials were significantly reduced and the expression levels of autophagic markers were significantly downregulated.

Effects of damage-regulated autophagy regulator gene on the SGC7901 human gastric cancer cell line.

The aim of this study was to investigate the effects of the adenoviral-mediated autophagy gene, damage-regulated autophagy regulator (DRAM), on the proliferation and autophagy of SGC7901 human gastric cancer cells in vitro. The recombinant adenovirus, AdMax-pDC315-DRAM-EGFP, working as a virus vector of DRAM was constructed and infected into the SGC7901 human gastric cancer cell line. The MTT assay was used to determine the growth rate of the SGC7901 cells. Activation of autophagy was monitored with monodansylcadaverin (MDC) staining following AdMax-pDC315-DRAM-EGFP treatment. Immunofluorescent staining was used to examine the expression of microtubule-associated protein 1 light chain 3 (LC3), and western blotting was used to examine the expression of apoptosis- and autophagy-associated proteins, including Beclin1, p53, p21 and B-cell lymphoma 2 (Bcl-2), in the culture supernatant. The viability of the SGC7901 cells was activated by AdMax-pDC315-DRAM-EGFP treatment. The AdMax-pDC315-DRAM-EGFP-treated cells exhibited positive LC3 expression detected by immunoreactivity and MDC staining. Inductions in the expression of the apoptosis-related proteins, p53 and p21, and the autophagic protein, Beclin1, were revealed by western blot analysis. By contrast, downregulation of the apoptosis-related protein, Bcl-2, following AdMax-pDC315-DRAM-EGFP treatment was identified. In conclusion, the present study demonstrated that AdMax-pDC315-DRAM-EGFP treatment resulted in upregulation of the level of autophagy and induction of cell proliferation in the SGC7901 human gastric cancer cell line in vitro.

Proximal gastrectomy versus total gastrectomy for proximal gastric carcinoma. A meta-analysis on postoperative complications, 5-year survival, and recurrence rate.

OBJECTIVE: To compare proximal gastrectomy (PG) with total gastrectomy (TG) for proximal gastric carcinoma, through the 5-year survival rate, recurrence rate, postoperative complications, and long-term life quality. METHODS: The meta-analysis was carried out in the General Surgery Department of the Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China. We searched Medline, EMBASE, and the Cochrane Library from June to November 2012. The literature searches were carried out using medical subject headings and free-text word: `proximal gastrectomy` `total gastrectomy` `partial gastrectomy` `stomach neoplasms` and `gastric cancer`. Two different reviewers carried out the search and evaluated studies independently. RESULTS: Two randomized controlled trials and 9 retrospective studies were included. A total of 1364 patients were included in our study. Our analysis showed that there is no statistically significant difference in 5-year survival rate between PG and TG (60.9% versus 64.4%). But, the recurrence is higher in the PG group than the TG (38.7% versus 24.4%). The anastomotic stenosis rate is also higher in the PG than the TG (27.4% versus 7.4%). CONCLUSION: Proximal gastrectomy is an option for upper third gastric cancer in terms of safety. However, it is associated with high risk of reflux symptoms and anastomotic stenosis. Therefore, TG should be the first choice for proximal gastric cancer to prevent reflux symptoms.

[Correlation of single nucleotide polymorphisms of X-ray repair cross complementing group 1 gene to hereditary susceptibility of colorectal cancer].

OBJECTIVE: To investigate the correlation of single nucleotide polymorphisms (SNP) of XRCC1 gene to hereditary susceptibility of colorectal cancer. METHODS: XRCC1 genotypes in 124 colorectal cancer patients and 214 matched healthy people as control were analyzed by SnaP Shot SNP-typing technique. Five different inheritance models including codominant, dominant, recessive, overdominant and log-additive were analyzed using logistic regression model. The haplotype distribution was estimated with phase and its correlation with the risk of colorectal cancer was evaluated. RESULTS: The frequencies of mutant 25487G-A, 25489C-T and 1799782C-T alleles were 0.20, 0.11, 0.32 respectively in the patients, and 0.23, 0.13, 0.34 in the controls. There was no significant correlation of polymophisms of XRCC1 gene to the risk of colorectal cancer in 5 different inheritance models (P>0.05). GCT, GCC, ACC and GTC were the most common haplotypes and the odds ratios were 1, 1.35, 0.90 and 0.84 respectively. There was no significant difference of distribution between 2 groups in haplotypes. CONCLUSION: Polymorphisms of XRCC1 gene, including rs25487, rs25489, rs1799782, are not associated with to the risk of colorectal cancer.

Effects of small interfering RNA inhibit Class I phosphoinositide 3-kinase on human gastric cancer cells.

AIM: To investigate the effects of small interfering RNA (siRNA)-mediated inhibition of Class I phosphoinositide 3-kinase (Class I PI3K) signal transduction on the proliferation, apoptosis, and autophagy of gastric cancer SGC7901 and MGC803 cells. METHODS: We constructed the recombinant replication adenovirus PI3K(I)-RNA interference (RNAi)-green fluorescent protein (GFP) and control adenovirus NC-RNAi-GFP, and infected it into human gastric cancer cells. MTT assay was used to determine the growth rate of the gastric cancer cells. Activation of autophagy was monitored with monodansylcadaverine (MDC) staining after adenovirus PI3K(I)-RNAi-GFP and control adenovirus NC-RNAi-GFP treatment. Immunofluorescence staining was used to detect the expression of microtubule-associated protein 1 light chain 3 (LC3). Mitochondrial membrane potential was measured using the fluorescent probe JC-1. The expression of autophagy was monitored with MDC, LC3 staining, and transmission electron microscopy. Western blotting was used to detect p53, Beclin-1, Bcl-2, and LC3 protein expression in the culture supernatant. RESULTS: The viability of gastric cancer cells was inhibited after siRNA targeting to the Class I PI3K blocked Class I PI3K signal pathway. MTT assays revealed that, after SGC7901 cancer cells were treated with adenovirus PI3K(I)-RNAi-GFP, the rate of inhibition reached 27.48% ± 2.71% at 24 h, 41.92% ± 2.02% at 48 h, and 50.85% ± 0.91% at 72 h. After MGC803 cancer cells were treated with adenovirus PI3K(I)-RNAi-GFP, the rate of inhibition reached 24.39% ± 0.93% at 24 h, 47.00% ± 0.87% at 48 h, and 70.30% ± 0.86% at 72 h (P < 0.05 compared to control group). It was determined that when 50 MOI, the transfection efficiency was 95% ± 2.4%. Adenovirus PI3K(I)-RNAi-GFP (50 MOI) induced mitochondrial dysfunction and activated cell apoptosis in SGC7901 cells, and the results described here prove that RNAi of Class I PI3K induced apoptosis in SGC7901 cells. The results showed that adenovirus PI3K(I)-RNAi-GFP transfection induced punctate distribution of LC3 immunoreactivity, indicating increased formation of autophagosomes. The results showed that the basal level of Beclin-1 and LC3 protein in SGC7901 cells was low. After incubating with adenovirus PI3K(I)-RNAi-GFP (50 MOI), Beclin-1, LC3, and p53 protein expression was significantly increased from 24 to 72 h. We also found that Bcl-2 protein expression down-regulated with the treatment of adenovirus PI3K(I)-RNAi-GFP (50 MOI). A number of isolated membranes, possibly derived from ribosome-free endoplasmic reticulum, were seen. These isolated membranes were elongated and curved to engulf a cytoplasmic fraction and organelles. We used transmission electron microscopy to identify ultrastructural changes in SGC7901 cells after adenovirus PI3K(I)-RNAi-GFP (50 MOI) treatment. Control cells showed a round shape and contained normal-looking organelles, nucleus, and chromatin, while adenovirus PI3K(I)-RNAi-GFP (50 MOI)-treated cells exhibited the typical signs of autophagy. CONCLUSION: After the Class I PI3K signaling pathway has been blocked by siRNA, the proliferation of cells was inhibited and the apoptosis of gastric cancer cells was enhanced.

SN50 enhances the effects of LY294002 on cell death induction in gastric cancer cell line SGC7901.

INTRODUCTION: In the previous study, we found that the inhibition of phosphatidylinositol 3-kinase (PI3K) by LY294002 induced SGC7901 cell death in vitro. We did not know whether SN50, which is a specific inhibitor of nuclear factor κB (NF-κB), could increase the cell death induction of gastric cancer of LY294002 in vitro, and we also wanted to know the mechanism of it, which might be applied to clinical tumor therapy. MATERIAL AND METHODS: The 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the cytotoxic effects of the drugs. Mitochondrial membrane potential was measured using the fluorescent probe JC-1. Hoechst 33258 staining was used to detect apoptosis and necrosis morphological changes after LY294002 and/or SN50 treatment. Expression of p53, PUMA and Beclin1 were determined with real-time polymerase chain reaction (RT-PCR) analysis. We used transmission electron microscopy to identify ultrastructural changes in SGC7901 cells after LY294002 and/or SN50 treatment. RESULTS: In this study, we found that treating the human gastric cancer cells SGC7901 with SN50 could significantly enhance the effects of LY294002 on inducing cell death after 24 h, compared to the control group (p < 0.05). Detection of mitochondrial potential and transmission electron microscopic examination indicated that the rate of cell death increased progressively. The expression of p53, PUMA and Beclin1 was up-regulated. CONCLUSIONS: The NF-κB inhibitor SN50 could enhance the role of LY294002 on inducing cell death of human gastric cancer cells SGC7901, which might be a promising new approach to gastric cancer therapy.