Aizhen Cai

Decreased expression of Sox7 correlates with the upregulation of the Wnt/β-catenin signaling pathway and the poor survival of gastric cancer patients

Sox7 is a tumor suppressor gene that plays an important role in the inhibition and progression of cancer. In the present study, we sought to investigate Sox7 expression in gastric cancer (GC) and its association with the Wnt/β-catenin signaling pathway. We also wished to determine its clinicopathological significance and prognostic implications. Sox7 expression and its effects on the Wnt/β-catenin signaling in vitro were assessed by reverse transcription-polymerase chain reaction using the AGS, MKN-45 and GES-1 gastric cell lines. We also used immunohistochemistry on paraffin-embedded tissue samples and western blot analysis on fresh tissue samples from patients with GC. The results revealed that Sox7 expression was significantly lower in the GC samples than in distal normal tissues, which was in accordance with our results obtained from our in vitro experiments on the cell lines. However, the expression levels of β-catenin were significantly higher. Sox7 and β-catenin expression significantly correlated with the depth of invasion, lymph node metastasis, distant metastasis and the TNM stage. Patient samples that were Sox7-negative correlated with a significantly shorter survival time. Multivariate survival analysis revealed that Sox7 and β-catenin had an independent effect on the survival of GC patients. Sox7 and β-catenin expression in GC had a negative liner correlation with each other. Our findings suggest that Sox7 plays an important role in inhibiting tumorigenesis and progression, and may be a potential marker for predicting the prognosis of patients with GC.

Diagnostic and prognostic value of circulating tumor DNA in gastric cancer: a meta-analysis

Background Circulating tumor DNA (ctDNA) has offered a minimally invasive approach for detection and measurement of gastric cancer (GC). However, its diagnostic and prognostic value in gastric cancer still remains unclear. Results A total of 16 studies comprising 1193 GC patients met our inclusion criteria. The pooled sensitivity and specificity were 0.62 (95% confidence intervals (CI) 0.59−0.65) and 0.95 (95% CI 0.93–0.96), respectively. The AUSROC (area under SROC) curve was 0.94 (95% CI 0.89–0.98). The results showed that the presence of certain ctDNA markers was associated with larger tumor size (OR: 0.26, 95% CI 0.11–0.61, p = 0.002), TNM stage (I + II/III + IV, OR: 0.11, 95% CI 0.07−0.17, p = 0.000), as well as H. pylori infection. (H.p negative/H.p positive, OR: 0.57, 95% CI 0.36–0.91, p = 0.018). Moreover, there was also a significant association between the presence of ctDNA and worse overall survival (HR 1.77, 95% CI 1.38−2.28, p < 0.001), as well as disease-free survival (HR 4.36, 95% CI 3.08−6.16, p < 0.001). Materials and Methods Pubmed, Embase, Cochrane Library and Web of Science databases were searched for relating literature published up until November 30, 2016. Diagnostic accuracy variables were pooled by the Meta-Disc software. Engauge Digitizer and Stata software were applied for prognostic data extraction and analysis. Conclusions Our meta-analysis indicates the detection of certain ctDNA targets is significantly associated with poor prognosis of GC patients, with high specificity and relatively moderate sensitivity.

Shikonin induces mitochondria-mediated apoptosis and enhances chemotherapeutic sensitivity of gastric cancer through reactive oxygen species

The prognosis of gastric cancer remains poor due to clinical drug resistance. Novel drugs are urgently needed. Shikonin (SHK), a natural naphthoquinone, has been reported to trigger cell death and overcome drug resistance in anti-tumour therapy. In this study, we investigated the effectiveness and molecular mechanisms of SHK in treatment with gastric cancer. In vitro, SHK suppresses proliferation and triggers cell death of gastric cancer cells but leads minor damage to gastric epithelial cells. SHK induces the generation of intracellular reactive oxygen species (ROS), depolarizes the mitochondrial membrane potential (MMP) and ultimately triggers mitochondria-mediated apoptosis. We confirmed that SHK induces apoptosis of gastric cancer cells not only in a caspase-dependent manner which releases Cytochrome C and triggers the caspase cascade, but also in a caspase-independent manner which mediates the nuclear translocation of apoptosis-inducing factor and Endonuclease G. Furthermore, we demonstrated that SHK enhanced the chemotherapeutic sensitivity of 5-fluorouracil and oxaliplatin in vitro and in vivo. Taken together, our data show that SHK may be a novel therapeutic agent in the clinical treatment of gastric cancer.

Association of thymidylate synthase expression and clinical outcomes of gastric cancer patients treated with fluoropyrimidine-based chemotherapy: a meta-analysis.

Purpose Although several studies have suggested an association between thymidylate synthase (TS) expression and outcomes of gastric cancer (GC) patients treated with fluoropyrimidine-based chemotherapy (FUC), the predictive value of TS for response and survival in this setting is unclear. This meta-analysis aimed to estimate prognostic and predictive significance of TS more precisely. Methods We searched PubMed, Embase, Cochrane Library, and Web of Science databases for literature published up to June 2015. Primary outcomes included hazard ratios (HRs) for overall survival (OS), and event-free survival (EFS) and odds ratio (OR) for chemotherapy response. Fixed- or random-effects models were used to calculate pooled HR and OR according to heterogeneity. Results A total of 2,442 GC patients in 25 studies met our inclusion criteria. Response rates for FUC were significantly lower in patients with high TS expression than in those with low expression (OR: 0.43, 95% confidence interval [CI]: 0.22–0.84, P=0.013). High TS expression was significantly correlated with unfavorable OS (HR: 1.62, 95% CI: 1.28–2.05, P<0.001) and EFS (HR: 1.54, 95% CI: 1.22–1.93, P<0.001) in advanced disease. However, TS expression was not significantly related to OS (HR: 1.06, 95% CI: 0.74–1.50, P=0.760) or EFS (HR: 1.16, 95% CI: 0.84–1.61, P=0.374) in the adjuvant setting. Conclusion Higher TS expression might predict drug resistance and adverse prognosis in patients with advanced GC treated with FUC.

Comparison between laparoscopic and open surgery for large gastrointestinal stromal tumors: A meta-analysis

AIM To investigate whether laparoscopic surgery is as safe and feasible as open resection for patients with larger gastrointestinal stromal tumors (GISTs) (≥ 5 cm). METHODS A systematic search of PubMed, EMBASE, Web of Science and the Cochrane Library database was performed. Relevant studies of laparoscopic and open surgery for GISTs of > 5 cm published before December 2016 were identified from these databases. The quality of the studies was assessed by the Newcastle-Ottawa Quality Assessment Scale. The tumor size, operation time, blood loss, postoperative hospital stay, complication rate, and disease-free survival rate were assessed. The software Stata (version 12.0) was used for the meta-analysis. RESULTS Five clinical trials comprising 209 patients with GISTs of similar larger sizes were evaluated. The pooled analysis of 100 patients in the laparoscopic resection group and 109 patients in the open resection group demonstrated that laparoscopic surgery was significantly associated with a shorter postoperative hospital stay (P < 0.001) and less blood loss (P = 0.002). Moreover, there were no statistically significant differences in the operation time (P = 0.38), postoperative complication rate (P = 0.88), or disease-free survival rate (P = 0.20) between two groups. CONCLUSION Our findings revealed that for patients with large GISTs of comparable sizes, laparoscopic surgery did not significantly influence the operation factors or clinical outcomes compared with open surgery. This suggests that laparoscopic resection is as acceptable as open surgery for treatment of large gastric GISTs.

Ring finger protein 43 associates with gastric cancer progression and attenuates the stemness of gastric cancer stem-like cells via the Wnt-β/catenin signaling pathway

BackgroundRing finger protein 43 (RNF43) is a member of the transmembrane E3 ubiquitin ligase family that was originally found in stem cells and plays important roles in tumor formation and progression. Our previous study indicated that RNF43 might be a tumor suppressor protein in gastric cancer. Given its antagonistic relationship with leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5), one of the gastric cancer stem cell markers, investigation of the potential role of RNF43 in gastric stem cancer cells is necessary.MethodsImmunohistochemistry staining, western blot analysis, and quantitative reverse transcription polymerase chain reaction were used to determine the mRNA and protein expression level of RNF43 and other Wnt pathway factors. Gastric cancer stem-like cells were obtained from gastric cancer tumor and cell lines by tumorsphere culture. The adeno-associated virus system was used to upregulate RNF43 expression in cancer cells. Functional experiments including tumorsphere formation, chemotherapy resistance, surface marker detection, and tumor xenograft assay were performed to measure stem-like properties in gastric cancer stem-like cells after RNF43 overexpression.ResultsRNF43 loss was significantly associated with TNM stage, distant metastasis, and Lauren classification, and predicted worse prognosis in gastric cancer patients. RNF43 expression was even lower in tumorspheres derived from tumor tissues or cell lines compared with adherent cancer cells and normal gastric cells. Overexpression of RNF43 in gastric cancer cells impaired their stem-like properties, including sphere formation ability, chemoresistance in vitro, and tumorigenicity in vivo. Moreover, Wnt pathway-related proteins were decreased in RNF43-overexpressing cells, while Wnt pathway activators could reverse the trend to some extent.ConclusionsOur findings indicated that RNF43 might not only participate in gastric cancer progression, but also attenuate the stemness of gastric cancer stem-like cells through the Wnt/β-catenin pathway.

Expression of decorin in intestinal tissues of mice with inflammatory bowel disease and its correlation with autophagy

The aim of this study was to investigate the expression of decorin (DCN) in the intestinal tissues of mice with inflammatory bowel disease (IBD) and its correlation with autophagy. The IBD mouse model was created by intrarectal injection of trinitrobenzene sulfonic acid. The pathology of colon tissues of the mice was examined using hematoxylin and eosin staining. Expression of DCN and the proteins associated with autophagy was detected using immunohistochemistry. Normal human colon mucosal epithelial cells (NCM460 cells) were transfected with DCN expression plasmid and the expression of DCN and autophagy-associated proteins was detected by western blot analysis. Cell apoptosis was studied using an Annexin V apoptosis detection assay and intracellular autophagosomes were observed using electron microscopy. The IBD mouse model was successfully established. Thickening, edema and inflammatory cell infiltration of the intestinal wall were observed in the IBD mice. The expression of DCN as well as the autophagy-associated proteins beclin 1 and LC3B, was increased in the intestinal tissues of the IBD mice. Furthermore, in the NCM460 cells transfected with DCN, the expression of beclin 1 and LC3B was upregulated, while p62 expression was downregulated. Intracellular autophagosomes were increased and apoptosis was decreased in the cells with DCN overexpression. Inhibition of autophagy reversed the effects of DCN on apoptosis. Therefore, DCN is able to induce autophagy and protect intestinal cells during the occurrence and development of IBD.

ZnRF3 induces apoptosis of gastric cancer cells by antagonizing Wnt and Hedgehog signaling.

A large proportion of malignant cancers of the stomach are gastric adenocarcinoma type. In spite of many studies, the molecular basis for this cancer is still unclear. Deregulated cell proliferative signaling via Wnt/β-catenin and Hedgehog pathways is considered important in the pathogenesis of many cancers including the gastric cancer. Recent studies identified ZnRF3 protein, which is a E3-ubiquitin ligase and which is either deleted or mutated in cancers, to inhibit Wnt signaling. However, the significance of ZnRF3 in the control of gastric cancer and whether it also regulates Hedgehog signaling pathway, is not known. In the present study, we assessed the expression of ZnRF3 in gastric tumors and paracancerous tissues from 58 patients (44 male and 14 female) of different ages and related this to patient survival. We observed a clear relationship between ZnRF3 expression in paracancerous tissue and tumor size. Also, ZnRF3 expression was much higher in tumors from aged patients. Male patients showed higher mortality than the females. Mechanistic studies using normal gastric cells (GES1) and gastric cancer cells (MGC-803) infected with either AdZnRF3 or AdGFP viral vectors, revealed that ZnRF3 overexpression causes significantly more apoptosis and lowered proliferation of cancer cells. ZnRF3 overexpression led to greatly reduced levels of Lgr5, a component of Wnt signaling and also Gli1, a component of Hedgehog signaling. Thus, ZnRF3 negatively influences both the Wnt and Hedgehog proliferative pathways, and probably this way it negatively regulates cancer progression. These results suggest the importance of normal ZnRF3 function in checking the progression of cancer cell growth and indicate that a lack of this protein can lead to poorer clinical outcomes for gastric cancer patients.

A systematic review and meta-analysis of robot-assisted versus laparoscopically assisted gastrectomy for gastric cancer

Background: Robotic-assisted gastrectomy (RAG) has been used for gastric cancer since 2002. This meta-analysis was carried out to evaluate whether RAG is safer and more effective than conventional laparoscopically assisted gastrectomy (LAG) for gastric cancer. Methods: We performed a manual search for these 2 types of operations (RAG and LAG) in the PubMed, Embase, and the Cochrane Library databases up to April 30, 2016. Twelve nonrandomized controlled trials that reported on RAG and LAG for gastric cancer were included. Outcomes evaluated included operation time, number of retrieved lymph nodes, blood loss, length of the resection margin, complications, and postoperative hospital stay. Results: A total of 3744 patients in 12 studies were included (1134 patients in the RAG group and 2610 patients in the LAG group). The operation time was significantly shorter in the LAG group [weighted mean difference (WMD) 42.0 (95% confidence interval, 95% CI 28.11–55.89) minutes; P < .00001], while the loss of blood volume was lower in the RAG group (P = .01). The number of retrieved lymph nodes, duration of postoperative stay, length of the proximal resection margin, length of the distal resection margin, and postoperative complications were similar between groups. Conclusion: We conclude that RAG is a safe and appropriate treatment for gastric cancer patients in comparison to LAG. Nevertheless, RAG is not superior to LAG. Future research on RAG should focus on comparing the differences in retrieved lymph nodes in different tiers, evaluating the postoperative recovery and reducing the cost of the treatment.

Shikonin induces ROS-based mitochondria-mediated apoptosis in colon cancer

Colon cancer is the third most common malignancy worldwide, and chemotherapy is a widely used strategy in clinical therapy. Chemotherapy-resistant of colon cancer is the main cause of recurrence and progression. Novel drugs with efficacy and safety in treating colon cancer are urgently needed. Shikonin, a naphthoquinone derived from the roots of the herbal plant Lithospermum erythrorhizon, has been determined to be a potent anti-tumor agent. The aim of the present study was to detect the underlying anti-tumor mechanism of shikonin in colon cancer. We found that shikonin suppressed the growth of colon cancer cells in a dose-dependent manner in vitro and in vivo. Shikonin induced mitochondria-mediated apoptosis, which was regulated by Bcl-2 family proteins. Shikonin increased the generation of intracellular ROS, which played an upstream role in shikonin-induced apoptosis. Our data indicated that generation of ROS, down-regulated expression of Bcl-2 and Bcl-xL, depolarization of the mitochondrial membrane potential and activation of the caspase cascade were components of the programmed event of shikonin-induced apoptosis in colon cancer cells. In addition, shikonin presented minimal toxicity to non-neoplastic colon cells and no liver injury in xenograft models, showing safety in the control of colon cancer cell growth in vitro and in vivo. Taken together, our findings suggest that shikonin might serve as a potential novel therapeutic drug in the treatment of human colon cancer.