Guoqiang Chen

Microcystin-LR Induces Apoptosis via NF-κB/iNOS Pathway in INS-1 Cells

Cyanobacterial toxins, especially the microcystins, are found in eutrophied waters throughout the world, and their potential to impact on human and animal health is a cause for concern. Microcystin-LR (MC-LR) is one of the common toxic microcystin congeners and occurs frequently in diverse water systems. Recent work suggested that apoptosis plays a major role in the toxic effects induced by MC-LR in hepatocytes. However, the roles of MC-LR in pancreatic beta cells have not been fully established. The aim of the present study was to assess possible in vitro effects of MC-LR on cell apoptosis in the rat insulinoma cell line, INS-1. Our results demonstrated that MC-LR promoted selectively activation of NF-κB (increasing nuclear p50/p65 translocation) and increased the mRNA and protein levels of induced nitric oxide synthase (iNOS). The chronic treatment with MC-LR stimulated nitric oxide (NO) production derived from iNOS and induced apoptosis in a dose dependent manner in INS-1 cells. Meanwhile, this effect was inhibited by the NF-κB inhibitor PDTC, which reversed the apoptosis induced by MC-LR. Our observations indicate that MC-LR induced cell apoptosis via an iNOS-dependent pathway. A well-known nuclear transcription factor, NF-κB, is activated and mediates intracellular nitric oxide synthesis. We suggest that the apoptosis induced by chronic MC-LR in vivo presents a possible cause of β-cell dysfunction, as a key environmental factor in the development of diabetes mellitus.

Effect of early enteral nutrition on postoperative nutritional status and immune function in elderly patients with esophageal cancer or cardiac cancer

OBJECTIVE To explore the effect of early enteral nutrition (EN) on postoperative nutritional status, intestinal permeability, and immune function in elderly patients with esophageal cancer or cardiac cancer. METHODS A total of 96 patients with esophageal cancer or cardiac cancer who underwent surgical treatment in our hospital from June 2007 to December 2010 were enrolled in this study. They were divided into EN group (n=50) and parenteral nutrition (PN) group (n=46) based on the nutrition support modes. The body weight, time to first flatus/defecation, average hospital stay, complications and mortality after the surgery as well as the liver function indicators were recorded and analyzed. Peripheral blood samples were collected on the days 1, 4 and 7 after surgery. The plasma diamine oxidase (DAO) activity and D-lactate level were determined to assess the intestinal permeability. The plasma endotoxin levels were determined using dynamic turbidimetric assay to assess the protective effect of EN on intestinal mucosal barrier. The postoperative blood levels of inflammatory cytokines and immunoglobulins were determined using enzyme-linked immunosorbent assay (ELISA). RESULTS After the surgery, the time to first flatus/defecation, average hospital stay, and complications were significantly less in the EN group than those in the PN group (P<0.05), whereas the EN group had significantly higher albumin levels than the PN group (P<0.05). On the 7th postoperative day, the DAO activity, D-lactate level and endotoxin contents were significantly lower in the EN group than those in the PN group (all P<0.05). In addition, the EN group had significantly higher IgA, IgG, IgM, and CD4 levels than the PN group (P<0.05) but significantly lower IL-2, IL-6, and TNF-α levels (P<0.05). CONCLUSIONS In elderly patients with esophageal cancer or cardiac cancer, early EN after surgery can effectively improve the nutritional status, protect intestinal mucosal barrier (by reducing plasma endoxins), and enhance the immune function.

The expression of PEBP4 protein in lung squamous cell carcinoma

The phosphatidylethanolamine-binding protein 4 (PEBP4) is a member of the PEBP family. It not only plays a role in the inhibition of the MAPK signaling pathway but also is involved in the inhibition of the JNK pathway that promotes the activation of AKT. Recent research has also shown that overexpression of PEBP4 was related to the development, invasion, and metastasis of a variety of tumors. This study aimed to investigate the correlation between PEBP4 protein expression in lung squamous cell carcinoma tissue and the clinical pathology of lung squamous cell carcinoma. Immunohistochemistry was used to detect PEBP4 expression in lung squamous cell carcinoma tissue and adjacent normal tissue from 61 patients. Western blotting was used to detect changes in the expression of PEBP4 protein between lung squamous cell carcinoma tissue and adjacent normal tissues. The correlation of PEBP4 expression and the occurrence, development, and clinical pathology of lung squamous cell carcinoma was analyzed. Of 61 patients, four patients were PEBP4 negative (−; 6.6%) and 57 patients were positive (+ to +++; 93.4%). Of those positive for PEBP4 expression, 7 patients were weakly positive (+; 11.5%), 21 patients were positive (++; 34.4%), and 29 patients were strongly positive (+++; 47.5%). PEBP4 protein was more highly expressed in lung squamous cell carcinoma tissue than in the adjacent normal lung tissue (p < 0.05). In PEBP4-positive patients, PEBP4 protein expression was significantly greater in those with lymph node metastases than in those without (p < 0.05). PEBP4 expression was significantly lower in patients at early (I and II) stages than in patients at advanced (III and IV) stages (p < 0.05). In less differentiated lung squamous cell carcinomas, PEBP4 protein expression was greater (p < 0.05); however, this was unrelated to the gender, age, or tumor size of the patient (p > 0.05). PEBP4 protein overexpression was associated with the occurrence, invasion, and metastasis of lung squamous cell carcinoma.

PEBP4 gene expression and its significance in invasion and metastasis of non-small cell lung cancer.

The goal of this study was to investigate the function of phosphatidylethanolamine-binding protein 4 (PEBP4) in invasion and metastasis of non-small cell lung cancer (NSCLC). PEBP4 mRNA and protein expression in 56 cases of NSCLC tissues were detected using RT-PCR and Western blot, and the relationship between PEBP4 expression and invasion and metastasis of NSCLC was analyzed. The change in the invasive ability of human NSCLC cell line HCC827 was observed after knocking down PEBP4 expression using RNA interference. PEBP4 mRNA and protein expression in cancer tissues of patients with lymph node metastasis were significantly higher than those in patients without lymph node metastasis (p < 0.05). PEBP4 expression significantly decreased in HCC827 cells after transfection with PEBP4 siRNA (p < 0.01), and the number of HCC827 cells that migrated through Transwell chambers was significantly lower than that of non-transfected control and transfected control cells (p < 0.01). PEBP4 over-expression may promote the invasion and metastasis of NSCLC.

Correlation of E-cadherin and CD44v6 expression with clinical pathology in esophageal carcinoma.

Cell adhesion, important for maintaining tissue architecture, plays a role in numerous cancers and particularly in tumor progression. In the present study, we investigated perturbations in the expression of two important adhesion proteins, epithelial (E)-cadherin and CD44v6, in esophageal carcinoma (EC). EC specimens were obtained from 42 patients undergoing resection of EC; both cancer and adjacent normal tissue were collected. Expression of E-cadherin and CD44v6 was detected by immunohistochemistry and the correlation between the expression of these two proteins and their individual relationships with pathology were determined. E-cadherin expression in EC tissue was significantly less common than in adjacent normal tissue. Furthermore, absence of E-cadherin expression was correlated with infiltration depth, lymph node metastasis, distant metastases and TNM stage (P<0.05), but not with gender, age, differentiation or tumor size. By contrast, CD44v6 expression in EC was significantly higher than that in adjacent normal tissue and was correlated with differentiation, distant metastases and TNM stage (P<0.05), but not with other clinicopathological parameters. Additionally, we observed a negative correlation between E-cadherin and CD44v6 expression in EC (P<0.05). Based on their correlations with pathology, we suggest that the expression of E-cadherin and CD44v6 is important roles in promoting the infiltration and metastasis of EC.

Phosphatidylethanolamine-binding protein 4 promotes lung cancer cells proliferation and invasion via PI3K/Akt/mTOR axis

BACKGROUND While phosphatidylethanolamine-binding protein 4 (PEBP4) is a key factor in the malignant proliferation and metastasis of tumor cells, the exact regulatory network governing its roles remains unclear. This study was designed to investigate the effect of PEBP4 on PI3K/Akt/mTOR pathway and explore its molecular network that governs the proliferation and metastasis of tumor cells. METHODS After the recombinant plasmid pcDNA3.1-PEBP4 was constructed, the recombinant plasmid pcDNA3.1-PEBP4 and PEBP4-targeting siRNA were transfected into lung cancer HCC827 cell line. The expressions of PI3K/Akt/mTOR pathway components in HCC827 cells in each group were determined using Western blotting. In the HCC827 cells, the effect of PI3K pathway inhibitor LY294002 on the expressions of PI3K/Akt/mTOR pathway components under the effect of PEBP4 was determined using Western blotting, and the effects of LY294002 on the cell viability, proliferation, and migration capabilities under the overexpression of PEBP4 were determined using MTT method, flow cytometry, and Transwell migration assay. Furthermore, the effect of mTOR inhibitor rapamycin (RAPA) on the expressions of PI3K/Akt/mTOR pathway components under the effect of PEBP4 was determined using Western blotting, and the effects of RAPA on the cell viability, proliferation, and migration capabilities under the overexpression of PEBP4 were determined using MTT method, flow cytometry, and Transwell migration assay. RESULTS As shown by Western blotting, the protein expressions of p-Akt and phosphorylated mTOR (p-mTOR) were significantly higher in the pcDNA3.1-PEBP4-transfected group than in the normal control group and PEBP4 siRNA group (P<0.05); furthermore, the protein expressions of p-Akt and p-mTOR significantly decreased in the PEBP4 targeting siRNA-transfected group (P<0.05). Treatment with LY294002 significantly inhibited the protein expressions of p-Akt and p-mTOR in HCC827 cells (P<0.05). In contrast, treatment with RAPA only significantly inhibited the protein expression of p-mTOR (P<0.05). As shown by MTT, flow cytometry, and Transwell migration assay, both LY294002 and RAPA could significantly lower the viability of HCC827 cells and inhibit their proliferation and invasion (P<0.05); meanwhile, they could reverse the effect of PEBP4 in promoting the proliferation and migration of HCC827 cells (P<0.05). CONCLUSIONS The overexpression of PEBP4 increases the phosphorylation levels of Akt and mTOR in lung cancer cells. The PI3K/Akt/mTOR signaling axis may be a key molecular pathway via which PEBP4 promotes the proliferation and invasion of non-small cell lung cancer (NSCLC) cells; also, it may serve as a potential therapeutic target.

PEBP4 enhanced HCC827 cell proliferation and invasion ability and inhibited apoptosis.

The purposes of this study were to investigate the effects of phosphatidylethanolamine-binding protein 4 (PEBP4) on the cell growth, proliferation, apoptosis, and invasion of non-small cell lung cancer (NSCLC) cells and to provide evidence for future treatment options for NSCLC. Western blot assays were performed to examine PEBP4 protein expression levels in NSCLC cell lines (HCC827, A549, NCI-H661, NCI-H292, and 95-D) and a normal human bronchial epithelial (HBE) cell line. A PEBP4 shRNA expression vector was constructed and transfected into HCC827 cells. Subsequently, the effects of PEBP4 on the cell viability, cell cycle distribution, apoptosis levels, and invasion properties of HCC827 cells were analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, flow cytometry analyses, and transwell invasion assays. In addition, the effects of PEBP4 on the expression of proteins including cyclin D1, p53, Bcl-2, MMP-2, and MMP-9 were investigated. PEBP4 was highly expressed in lung cancer cells (HCC827, A549, NCI-H661, NCI-H292, and 95-D), but its expression was low in HBE cells. Cell viability, cell proliferation, and invasion of HCC827 cells in the PEBP4 knockdown group were significantly lower than that in the negative control and blank control groups (p < 0.05), and there were no significant differences between the negative and blank control groups in terms of cell viability, cell proliferation, apoptosis, and invasion. In HCC827 cells, the expression levels of cyclin D1, Bcl-2, MMP-2, and MMP-9 in the PEBP4 knockdown group were significantly lower (p < 0.05), and the expression of p53 protein was significantly higher than that in the negative and blank control groups (p < 0.05). There were no significant differences between the negative and blank control groups in the expression levels of cyclin D1, p53, Bcl-2, MMP-2, and MMP-9. In conclusion, PEBP4 enhanced HCC827 cell proliferation and invasion ability and inhibited apoptosis. Decreased PEBP4 expression may play a role in the reduced invasion ability and increased apoptosis of the human NSCLC cell line HCC827.