Kecheng Zhang

Genome-Wide lncRNA Microarray Profiling Identifies Novel Circulating lncRNAs for Detection of Gastric Cancer.

Long non-coding RNAs (lncRNAs) can serve as blood-based biomarkers for cancer detection. To identify novel lncRNA biomarkers for gastric cancer (GC), we conducted, for the first time, genome-wide lncRNA screening analysis in two sets of samples: five paired preoperative and postoperative day 14 plasma samples from GC patients, and tissue samples from tumor and adjacent normal tissues. Candidate tumor-related lncRNAs were then quantitated and evaluated in three independent phases comprising 321 participants. The expression levels of lncRNAs were also measured in GC cell lines and the corresponding culture medium. Biomarker panels, lncRNA-based Index I and carcinoembryonic antigen (CEA)-based Index II, were constructed using logistic regression, and their diagnostic performance compared. Fagans nomogram was plotted to facilitate clinical application. As a result, we identified five novel plasma lncRNAs (TINCR, CCAT2, AOC4P, BANCR and LINC00857), which, when combined in the lncRNA-based Index I, outperformed the CEA-based Index II (P < 0.001) and could distinguish GC patients from healthy controls with an area under the receiver-operating curve (AUC) of 0.91 (95% confidence interval (CI): 0.88-0.95). The lncRNA-based index decreased significantly by postoperative day 14 (P = 0.016), indicating its ability to monitor tumor dynamics. High values of the lncRNA-based index were correlated with tumor size (P = 0.036), depth of invasion (P = 0.025), lymphatic metastasis (P = 0.012) and more advanced tumor stages (P = 0.003). The lncRNA-based index was also able to discriminate GC patients from precancerous individuals and patients with gastrointestinal stromal tumor with AUC values of 0.82 (95% CI: 0.71-0.92) and 0.80 (95% CI: 0.68-0.91), respectively. Taken together, our findings demonstrate that this panel of five plasma lncRNAs could serve as a set of novel diagnostic biomarkers for GC detection.

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.

Phase II Trial of Adjuvant Immunotherapy with Autologous Tumor-derived Gp96 Vaccination in Patients with Gastric Cancer

Background/Aims: Autologous, tumor-derived, heat shock protein gp96 peptide complexes have antitumor potential. We conducted the first Phase II trial to evaluate the safety and efficacy of gp96 vaccination in adjuvant settings for patients with gastric cancer. Methods: We enrolled 73 consecutive patients from October 2012 to December 2015. Thirty-eight patients received gp96 vaccination plus chemotherapy and 35 received chemotherapy alone. The primary endpoints were disease-free survival (DFS) and toxicity. The secondary endpoints were overall survival (OS) and tumor-specific immune responses. Results: There were comparable baseline characteristics between the two groups. Tumor-specific immune responses increased significantly after gp96 vaccination. gp96 vaccination plus chemotherapy was well tolerated and there were no gp96-related serious adverse events. Patients who received gp96 vaccination had improved DFS compared with those who did not [p = 0.045; hazard ratio (HR): 0.47; 95% confidence interval (CI): 0.23-0.96]. The 2-year OS rates were 81.9% and 67.9% for the gp96 vaccination and chemotherapy alone group, respectively (p = 0.123; HR: 0.42; 95% CI: 0.15-1.24). Conclusion: gp96 vaccination elicits tumor-specific immune responses and can be safely used in adjuvant settings combined with chemotherapy. Patients with less-aggressive diseases might benefit from gp96 therapy.

Serum HER2 Is a Potential Surrogate for Tissue HER2 Status in Gastric Cancer: A Systematic Review and Meta-Analysis

Determining the expression level of human epidermal growth factor receptor 2 (HER2) in tumor tissue is of great importance for personalized therapy in gastric cancer. Although several studies have investigated whether serum HER2 can serve as a surrogate for tissue HER2 status, results have been inconsistent. We therefore performed a meta-analysis of published clinical studies in an attempt to address this problem. PubMed, Embase, Web of Science, the Cochrane Library and Science Direct were queried for eligible studies that could provide sufficient data to construct 2 × 2 contingency tables. The quality of the studies included in the meta-analysis was assessed in accordance with the revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) criteria. The pooled sensitivity, specificity and diagnostic odds ratio (DOR) were calculated for the eligible studies. The summary receiver operating characteristic (SROC) curve was constructed and the area under the SROC (AUSROC) was used to evaluate overall diagnostic performance. Eight studies comprising a total of 1170 participants were included in our meta-analysis. The pooled sensitivity, specificity and DOR were 0.39 (95% CI: 0.21–0.61), 0.98 (95% CI: 0.87–1.00), and 27 (95% CI: 9–81), respectively. The AUSROC was 0.77 (95% CI: 0.73–0.80) and Deeks funnel plot suggested the absence of publication bias (p = 0.91). Meta-regression analysis indicated that threshold effect was the main source of heterogeneity. Assays for evaluating serum HER2 levels are highly specific and demonstrate moderate diagnostic performance for HER2 tissue status in 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.

Ability of Serum C-Reactive Protein Concentrations to Predict Complications After Laparoscopy-Assisted Gastrectomy: A Prospective Cohort Study

AbstractInflammatory markers, including C-reactive protein (CRP) and white blood cell (WBC), are widely available in clinical practice. However, their predictive roles for infectious complications following laparoscopy-assisted gastrectomy (LAG) have not been investigated. Our aim was to investigate the diagnostic accuracy of CRP concentrations and WBC counts for early detection of infectious complications following LAG and to construct a nomogram for clinical decision-making.The clinical data of consecutive patients who underwent LAG with curative intent between December 2013 and March 2015 were prospectively collected. Postoperative complications were recorded according to the Clavien–Dindo classification. The diagnostic value of CRP concentrations and WBC counts was evaluated by area under the curve of receiver-operating characteristic curves. Optimal cutoff values were determined by Youden index. Univariate and multivariate logistic regression analyses were performed to identify risk factors for complications, after which a nomogram was constructed.Twenty-nine of 278 patients (10.4%) who successfully underwent LAG developed major complications (grade ≥III). CRP concentration on postoperative day 3 (POD 3) and WBC count on POD 7 had the highest diagnostic accuracy for major complications with an area under the curve value of 0.86 (95% confidence interval [CI], 0.79–0.92] and 0.68 (95% CI, 0.56–0.79) respectively. An optimal cutoff value of 172.0 mg/L was identified for CRP, yielding a sensitivity of 0.79 (95% CI, 0.60–0.92) and specificity 0.74 (95% CI, 0.68–0.80). Multivariate analysis identified POD3 CRP concentrations ≥172.0 mg/L, Eastern Cooperative Oncology Group Performance Status ≥1, presence of preoperative comorbidity, and operation time ≥240 min as risk factors for major complications after LAG.The optimal cut-off value of CRP on POD3 to predict complications following LAG was 172.0 mg/L and a CRP-based nomogram may contribute to early detection of complications after LAG.

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.

RNAi-mediated inhibition of Lgr5 leads to decreased angiogenesis in gastric cancer

Leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) is a novel gastric cancer marker. However, it is unclear whether it can play roles in tumor angiogenesis. In this study, we aim to investigate the role of Lgr5 on gastric cancer angiogenesis. Lgr5, VEGF expression levels and microvessel density (MVD) were detected in tumor tissue. Then, Lgr5 mRNA was downregulated by small interference RNA technique. Western blotting and real-time quantitative PCR (qRT-PCR) were performed to detect the expression of Lgr5 and VEGF protein and mRNA in Lgr5 siRNA-transfected gastric cancer cells. The effect of silencing Lgr5 on angiogenesis was examined by assessing human umbilical vein endothelia cell (HUVEC) capillary tube formation. The results indicated that Lgr5 expression was upregulated in gastric cancer and positively correlated with VEGF (r=0.305, P=0.001) and MVD (r=0.312, P=0.001). Silencing of Lgr5 expression resulted in suppression of VEGF mRNA and protein (all P=0.001). Moreover, when HUVECs were stimulated with conditioned medium from Lgr5 siRNA-transfected gastric cancer cells, tube formation was significantly decreased (2.51 ± 0.19 mm/mm2) compared with the treatment with regular cell culture medium (DMEM) (7.34 ± 0.30 mm/mm2) or medium from control siRNA-transfected cells (7.18 ± 0.33 mm/mm2) (all P=0.001). In conclusion, Lgr5 plays important roles in angiogenesis. Lgr5-specific siRNA could be designed into an effective therapeutic agent to inhibit gastric cancer angiogenesis.