Daren Liu

CD97 promotes gastric cancer cell proliferation and invasion through exosome-mediated MAPK signaling pathway.

AIM To investigate the mechanism underlying the promoting role of CD97 in gastric cancer cell proliferation and invasion. METHODS Two types of exosomes released by gastric cancer cells with high (SGC/wt) or low (SGC/kd) CD97 expression were isolated by ultracentrifugation and identified by electron microscopy and western blot analysis. The influences of the two exosomes on gastric cancer cell proliferation and invasion were investigated by proliferation and Matrigel invasion assays. Exosomal miRNAs were subsequently isolated from the two samples and their miRNA profiles were compared via microarray assay analysis. Reverse transcription-quantitative real-time polymerase chain reaction was used to validate the microarray assay. Target genes of the differently expressed microRNAs were predicted based on five independent algorithms and were then subjected to gene oncology enrichment and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis. After identifying the pathway that was the most likely altered, tumor cells were treated with the two exosomes at different concentrations, and the pathway activation was identified through western blot analysis. RESULTS Exosomes isolated from SGC/wt cells significantly promoted tumor cell proliferation in a dose-dependent manner in vitro. SGC/wt exosomes also significantly elevated the invasiveness of both SGC/wt (129.67 ± 8.327 vs 76.00 ± 5.292, P < 0.001) and SGC/kd (114.52 ± 9.814 vs 45.73 ± 4.835, P < 0.001) cells as compared to the exosomes released by SGC/kd cells. Microarray assay of the two exosomes revealed that 62 miRNAs were differently regulated with a signal intensity of > 500 and a false discovery rate < 0.05. The following KEGG analysis defined the MAPK signaling pathway as the most likely candidate pathway that regulated tumor cell proliferation and invasion. Through western blot analysis, significant up-regulations of phosphorylated MAPKs, including extracellular signal-regulated kinase, Jun NH2-terminal kinase, and p38 mitogen-activated protein kinase, were detected in a dose-dependent manner in the SGC/wt exosomes treated groups, confirming activation of the MAPK signaling pathway stimulated by SGC/wt exosomes. CONCLUSION CD97 promotes gastric cancer cell proliferation and invasion in vitro through exosome-mediated MAPK signaling pathway, and exosomal miRNAs are probably involved in activation of the CD97-associated pathway.

The invasion and metastasis promotion role of CD97 small isoform in gastric carcinoma.

CD97 is over-expressed in the majority of gastric adenocarcinomas and is associated with its dedifferentiation and aggressiveness. Our previous results demonstrated that out of three CD97 isoforms tested, only the small one was able to promote increased invasiveness in vitro. Based on these data we further aimed to investigate the role of CD97 small isoform in gastric cancer progression in vivo by employing the cells with a stable CD97 small isoform knock-down and an orthotopic gastric cancer mouse model. We could demonstrate that the knock down of CD97/EGF1,2,5, led to a significant decrease in the number of cells penetrating the gelatin coated membrane as compared with control cells. In the gastric cancer mouse model, both the hypodermic and the orthotopic yielded tumor masses of the CD97/EGF1,2,5kd group and were significantly smaller than the control. Metastatic tumor cell number in early metastatic regional lymph nodes on post-operative day 42 was distinctly decreased in the CD97/EGF1,2,5kd group as compared with the SGC-NS group, and was accompanied with the downregulation of CD44, VEGFR, CD31 and CD97. We concluded in this study that CD97 small isoform not only supported gastric cancer local growth, but also promoted metastatic spread in orthotopically implanted mouse model suggesting involvement of the CD97 small isoform in the preparation of (pre)metastatic niche.

Influence of up-regulation of Notch ligand DLL4 on biological behaviors of human gastric cancer cells

AIM To investigate the potential roles of Delta-like ligand 4 (DLL4) on the biological behavior of gastric cancer cells and its molecular mechanisms. METHODS A recombinant eukaryotic expression vector containing human DLL4 gene was constructed and transfected into the human gastric cancer cell line SGC7901. Clones with up-regulated DLL4 were selected and amplified. The effect of DLL4 up-regulation on gastric cancer cell growth was assessed using cell growth assay. The migration and invasion were assessed using a transwell migration assay and matrigel invasion assay. Matrix metalloproteinases were detected using the zymogram technique. Cells were implanted subcutaneously into male BALB/c nu/nu mice. Tumor volumes were then calculated and compared. DLL4 staining in the implanted tumor was performed using immunohistochemistry technique. RESULTS Growth curves over a six-day time course showed significantly promoted cell proliferation of SGC7901 cells with up-regulated DLL4. DLL4 up-regulation in SGC7901 cells promoted the migration (205.4 ± 15.2 vs 22.3 ± 12.1, P < 0.05) and invasion (68.8 ± 5.3 vs 18.2 ± 6.0, P < 0.05) in vitro and tumorigenicity in vivo (2640.5 ± 923.6 mm(3) vs 1115.1 ± 223.8 mm(3), P < 0.05). Furthermore, significantly increased mRNA level and increased secretion of matrix metalloproteinase-2 (MMP-2) proenzyme were observed in SGC7901 cells with up-regulated DLL4. However, increased MMP-9 mRNA level but decreased extracellular MMP-9 proenzyme level was observed. CONCLUSION Our observations indicated a mechanism by which activation of DLL4-mediated Notch signaling promotes the expression and secretion of MMP-2 proenzyme and influences the progress of gastric cancer.

Systematic review of laparoscopy-assisted versus open gastrectomy for advanced gastric cancer.

ObjectiveThe study compared laparoscopy-assisted gastrectomy (LAG) with open gastrectomy (OG) in the management of advanced gastric cancer (AGC).MethodsLiterature search was performed in the Medline, Embase, and Cochrane Library databases to identify control studies that compared LAG and OG for AGC. A meta-analysis was conducted to examine the surgical safety and oncologic adequacy, using the random-effect model.ResultsSeven eligible studies including 815 patients were analyzed. LAG was associated with less blood loss, less use of analgesics, shorter time of flatus and periods of hospital stay, but longer time of operation. The incidence of most complications was similar between the two groups. However, LAG was associated with a lower rate of pulmonary infection (odds ratio (OR) 0.19; 95% confidence interval (CI) 0.05 to 0.68; P<0.05). No significant differences were noted in terms of the number of harvested lymph nodes (weighted mean difference (WMD) 1.165; 95% CI–2.000 to 4.311; P>0.05), overall mortality (OR 0.65; 95% CI 0.39 to 1.10; P>0.05), cancer-related mortality (OR 0.64; 95% CI 0.32 to 1.25; P>0.05), or recurrence (OR 0.62; 95% CI 0.33 to 1.16; P>0.05).ConclusionsLAG could be performed safely for AGC with adequate lymphadenectomy and has several short-term advantages compared with conventional OG. No differences were found in long-term outcomes. However, these results should be validated in large randomized controlled studies (RCTs) with sufficient follow-up.

HER-2 overexpression and survival in colorectal cancer: a meta-analysis

Objective: Numerous studies examining the relationship between human epidermal growth factor receptor 2 (HER-2) overexpression and survival in patients with colorectal cancer (CRC) have yielded controversial results. We therefore performed a meta-analysis more precisely to estimate its prognostic value. Methods: Published studies investigating the effect of HER-2 overexpression on CRC survival were identified; the hazard ratios (HRs) and their corresponding 95% confidence intervals (95% CIs) were pooled in terms of disease-specific or overall survival. Results: Eleven studies were included in the meta-analysis. The pooled data showed that HER-2 overexpression was negatively related to CRC survival (HR=1.10, 95% CI: 0.77–1.44). Subgroup analyses regarding test method and study quality also demonstrated little association between HER-2 overexpression and CRC survival (HR=0.89, 95% CI: 0.50–1.29; HR=0.90, 95% CI: 0.43–1.37, respectively). Conclusions: Regardless of several limitations, our study suggested that HER-2 overexpression probably had little impact on CRC survival.

Renoprotective activity of sivelestat in severe acute pancreatitis in rats

Acute pancreatitis, affecting 382,014 individuals annually in China, is life-threatening in its severe form. Since acute pancreatitis-associated morbidity or mortality is attributable mainly to functional failure of the vital organs, significant research efforts have focused on the identification of novel agents with potential organ-protective properties in the hope of developing approaches to improve the outcome of acute pancreatitis. In a previous study, we demonstrated that sivelestat, a specific inhibitor of neutrophil elastase (NE), is effective in protecting against lung failure in rats with taurocholate-induced acute pancreatitis. As part of the analyses extended from that study, the present study aimed to evaluate the role of sivelestat in the protection against acute pancreatitis-associated renal injury. Renal histopathology and major renal function parameters were analyzed in renal tissue and blood specimens collected from rats with acute pancreatitis induced by the surgical administration of sodium taurocholate in the presence or absence of sivelestat treatment and in sham-operated control rats at various time-points. The extended analyses demonstrated that: i) sodium taurocholate induced apparent renal injury and dysfunction manifested by histological anomalies, including vacuolization and apoptosis of the cells of the tubular epithelial lining in the kidney, as well as biochemical aberrations in the blood (increases in levels of blood urea nitrogen, creatinine and tumor necrosis factor-α) and renal tissue (robust increases in NE activity and induced neutrophil chemoattractant-1 levels); and ii) sivelestat treatment effectively attenuated all taurocholate-induced histological anomalies and biochemical aberrations. These observations strongly suggest that the NE inhibitor, sivelestat, is effective in protecting against acute pancreatitis-associated renal injury.

Target‑specific delivery of oxaliplatin to HER2‑positive gastric cancer cells in vivo using oxaliplatin‑au‑fe3o4‑herceptin nanoparticles

Gastric cancer is the fourth most common malignancy globally. In order to decrease the dosage and side effects of conventional chemotherapy, and achieve improved benefits from molecular targeted therapy, novel drug delivery systems were developed in the present study. Oxaliplatin-Au-Fe3O4-Herceptin® acts as a dual-functional nanoparticles (NPs) conjugate and possesses the capability of human epithelial growth factor receptor 2 (HER2) targeting and oxaliplatin delivery. The 8-20 nm Au-Fe3O4 were synthesized by decomposing iron pentacarbonyl on the surfaces of Au NPs in the presence of oleic acid and oleylamine. Following being coated with polyethylene glycol, the NPs possessed a ζ-potential of 13.8±1.6 mV and were demonstrated to exhibit no cytotoxicity when Fe concentration is <100 µg/ml via an MTS assay. Mass spectrometry analysis detected a peak at m/z 148,000, and Nuclear Magnetic Resonance indicated peaks at δ 3.51 (8.00H, s, 3-H), 2.97-3.02 (3.80H, t, 2-H) and 2.72-2.76 (3.72H, t, 1-H) following successful loading with Herceptin and oxaliplatin probes. A drug release assay via dialysis cassettes demonstrated that 25% of the oxaliplatin was released at pH 8.0, however >58% was released at pH 6.0 following 4 h incubation, indicating its pH-dependent release characteristic. The active targeting feature of oxaliplatin-Au-Fe3O4-Herceptin was verified in a subcutaneous xenograft mouse model containing SGC-7901 cells via detecting aggregated low intensity in T2-weighted magnetic resonance imaging, which was further confirmed by immunohistochemistry. Therefore, oxaliplatin-Au-Fe3O4-Herceptin is a promising multifunctional platform for simultaneous magnetic traceable and HER2 targeted chemotherapy for gastric cancer.

Management of differentiated thyroid carcinoma with bone metastasis: a case report and review of the Chinese literature

Differentiated thyroid carcinoma (DTC) is a common malignancy. The general treatments are thyroidectomy of the affected lobe along with lymphadenectomy. However, bone metastasis is rare in DTC compared with other malignancies and the management of metastasis foci is still controversial. Here we present a case of follicular thyroid carcinoma with the 6th cervical vertebra body metastasis successfully treated by total thyroidectomy, cervical corpectomy, and internal fixation, followed by hormone replacement therapy and radioiodine therapy. Eleven additional patients diagnosed as thyroid carcinoma with bone metastasis collected from Chinese literature between January 1996 and December 2013 were also reviewed. The mean age of the 12 patients at presentation was (53.9±9.2) years (rang, 42–72 years) and the male to female ratio was 1:2. Nine cases received total/near-total thyroidectomy or lobectomy while the other three patients refused for personal reasons. The interventions for bone metastasis were one-stage operation (9/12), I131 adjuvant therapy (3/12), chemotherapy (1/12), and no intervention (1/12). During the follow-up, two patients died of metastatic carcinoma recurrence, one died of multiple organ metastasis, and one with an unknown reason. We conclude that the management of thyroid carcinoma with bone metastasis needs multidisciplinary cooperation. Surgical resection is still the first choice for cure, while the combined one-stage operation on the primary and metastatic sites followed by hormone replacement therapy and radioiodine therapy is an applicable treatment.概要研究目的探究甲状腺癌骨转移的规范诊疗措施, 为提高甲状腺癌骨转移的生存期提供指导。创新要点本例病人通过普外科、 骨科联合手术, 内分泌激素替代治疗, I131治疗等多学科联合治疗, 取得较好的疗效, 对探究甲状腺癌骨转移的规范化诊疗措施有重要的指导意义。研究方法本文分析本科室一例甲状腺癌骨转移病人, 同时搜集了1996年至2013年中文文献报道的甲状腺癌骨转移患者11例, 通过统计其病理类型、 手术方式、 转移部位、 随访资料等, 讨论其规范化治疗方式。重要结论彻底的术前检查对发现甲状腺癌骨转移至关重要。 甲状腺癌骨转移需要多学科协同治疗, 手术治疗仍为首选, 联合手术的激素替代治疗、 I131治疗、 二膦酸盐治疗是较好的选择。 放疗的作用仍需大样本数据的评估。