Xiaoqian Wang

Vascular endothelial growth factor-C promotes the growth and invasion of gallbladder cancer via an autocrine mechanism

Vascular endothelial growth factor-C (VEGF-C) has a well-defined action on neoplastic lymphangiogenesis and angiogenesis through VEGF receptor-3 (VEGFR-3) and VEGFR-2, respectively, which are generally expressed in endothelial cells. The function of the VEGF-C/receptors pathway in tumor cell types is largely unknown. In this study, we examined the expression and role of VEGF-C/receptors in gallbladder cancer (GBC) cells. We examined the expression of VEGF-C in 50 surgical specimens from gallbladder cancer and three human gallbladder cancer cell lines. Both siRNA and neutralizing antibody to deplete the expression of VEGF-C were used to characterize the biological effect of VEGF-C in GBC NOZ cells. Furthermore, we examined the expression of its receptors, VEGFR-3 and VEGFR-2, in three human GBC cell lines. Our results are as follows: The expression of VEGF-C in the invasive marginal portion was significantly higher than the expression in the central portions. All the three GBC cell lines expressed VEGF-C. Treatment of NOZ cells with VEGF-C siRNA or a neutralizing antibody suppressed cell proliferation and invasion. Moreover, all the three GBC cell lines expressed VEGFR3, but only the NOZ cells expressed VEGFR-2 mRNA. Treatment of NOZ cells with a VEGFR-3 neutralizing antibody suppressed cell invasion, but treatment of NOZ cells with a VEGFR-2 neutralizing antibody suppressed cell proliferation and invasion. In conclusion, GBC cells express both VEGF-C and its receptors. VEGF-C may have a role in the progressive growth and invasion of human GBC through an autocrine mechanism.

HBx‐dependent activation of twist mediates STAT3 control of epithelium‐mesenchymal transition of liver cells

This study investigated the molecular mechanisms of liver cells with HBx expression on epithelium–mesenchymal transition (EMT) change using Western blot analysis and Transwell assay to assess EMT‐related protein expression and cell mobility. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were used to test the Twist promoter containing different STAT3 binding loci. Electrophoretic mobility band‐shift assay (EMSA) was used to detect Twist activity. Results showed that HBx expression affected the EMT‐related protein expression and the cell mobility of liver cancer cells (MHCC97) and liver cells (HL‐7702) in vitro or in vivo. These proteins exhibited reversed expression to a certain extent after Twist inhibition. In addition, the wound‐healing capability and the mobility of HL‐7702/HBx cells were lower than those treated with control‐siRNA. The expressions of p‐STAT3 and Twist were positively correlated with HBx expression. The second STAT‐3 binding sequence in the Twist promoter region of the HL‐7702/HBx cells was the first locus. Twist activity in the HL‐7702/HBx2 cells was higher than that in HL‐7702 cells. Moreover, the activity decreased when the cells were treated with HBx‐siRNA to inhibit HBx expression, or with STAT3 inhibitor to reduce STAT3 activation. Therefore, Twist is essential for the regulation of the mobility of liver cells with HBx expression. HBx activates the Twist promoter by activating STAT3 and promotes EMT occurrence in liver cells. J. Cell. Biochem. 114: 1097–1104, 2013.

Vascular endothelial growth factor-D promotes growth, lymphangiogenesis and lymphatic metastasis in gallbladder cancer.

Lymph node metastasis is a major prognostic factor for patients with gallbladder cancer (GBC), and greater understanding of the molecule mechanism of lymph node metastasis in GBC is needed to improve prognosis. VEGF-D has been implicated in the control of lymphangiogenesis in many carcinomas, but the biological function of VEGF-D in human GBC remains unclear. In this study, we analyzed the role of the VEGF-D in human GBC cells and addressed the functional role of VEGF-D using a xenograft mouse model. We examined the expression of VEGF-D in three human gallbladder cancer cell lines. A lentivirus-based effective VEGF-D siRNA vector was infected into GBC NOZ cells. The effect of VEGF-D siRNA on GBC NOZ cells was investigated by cell proliferation assay and invasion assay. Furthermore, we examined the role of VEGF-D-SiRNA on GBC NOZ cells in the mice of subcutaneous and orthotopic xenograft tumor. Our results are as follows: VEGF-D mRNA and protein were expressed in all three GBC cell lines (GBC-SD, NOZ, and SGC-996). We successfully selected D-3/siRNA as the most effective siRNA to silence VEGF-D expression after four VEGF-D siRNA plasmid transfection in NOZ cells. VEGF-D mRNA and protein expression were suppressed by lentivirus-mediated D-3/siRNA. D-3-RNAi-LV inhibited NOZ cells proliferation and invasion ability in vitro. D-3-RNAi-LV inhibited tumor growth and lymphangiogenesis in the NOZ cell subcutaneous xenograft model. D-3-RNAi-LV inhibited lymphangiogenesis and lymphatic metastasis in the NOZ cell orthotopic xenograft model. Furthermore, D-3-RNAi-LV inhibited tumor ascites and hepatic invasion in the NOZ cell orthotopic xenograft model. In conclusion, VEGF-D is involved and plays an important role in GBC progression, suggesting that VEGF-D may be a potential molecular target in the treatment of GBC.

Tumor necrosis factor-α promotes the lymphangiogenesis of gallbladder carcinoma through nuclear factor-κB-mediated upregulation of vascular endothelial growth factor-C.

Vascular endothelial growth factor (VEGF)‐C is an important lymphangiogenic factor involved in the lymphangiogenesis of gallbladder carcinoma (GBC) and the lymph node metastasis of the tumor. Tumor necrosis factor (TNF)‐α, a key inflammatory cytokine responding to chronic inflammation of GBC, has been reported to stimulate the expression of VEGF‐C in some nonneoplastic cells. But whether TNF‐α promotes the expression of VEGF‐C in GBC has yet to be determined. Therefore, in the present study, the concentration of TNF‐α and VEGF‐C and the lymphatic vessel density (LVD) in the clinical GBC specimens were analyzed, and a linear correlation was found between the concentration of TNF‐α and that of VEGF‐C, the lymphatic vessel density (LVD); The transcription and protein level of VEGF‐C in NOZ cell line were detected by real‐time polymerase chain reaction (PCR) and enzyme linked immunosorbent assay (ELISA), and TNF‐α enhanced the expression of VEGF‐C in NOZ cell lines in a dose and time‐dependent manner. Lymphatic tube formation in vitro was observed in a three‐dimensional coculture system consisting of HDLECs and NOZ cell lines, and lymphatic vessels of GBC in nude mice model was detected by immunohistochemistry. TNF‐α promoted the tube formation of lymphatic endothelial cells in vitro and the lymphangiogenesis of GBC in nude mice; The nuclear factor (NF)‐κB binding site on the VEGF‐C promoter was identified using Site‐directed mutagenesis, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation assay (ChIP). Taken together, TNF‐α can upregulate the expression of VEGF‐C and promote the lymphangiogenesis of GBC via NF‐κB combining with the promoter of VEGF‐C.

TNF-α promotes gallbladder cancer cell growth and invasion through autocrine mechanisms

Tumor necrosis factor-α (TNF-α) has been suggested to be a putative tumor promoter gene, and autocrine of TNF-α expression has been found in colon cancer and ovarian cancer. As the role of autocrine TNF-α in human gallbladder cancer has not yet been elucidated, the present study examined the expression of TNF-α in gallbladder cancer-derived cell lines. Based on the data, TNF-α mRNA and TNF-α protein expression differed significantly different between the cell lines. In addition, using siRNA targeting TNF-α, the vector, pGPU-GFP-siTNF-α, was constructed and then transfected into the SGC-996 cells (gallbladder cancer cell line) which express high levels of endogenous TNF-α. In vitro experiments indicated that the silencing of TNF-α in the SGC-996 cells significantly suppressed proliferation and invasion. However, apoptosis was not induced by the silencing of TNF-α. Furthermore, we traced the mechanisms underlying these effects and found that the silencing of TNF-α affected the TNF-α-AKT-NF-κB-Bcl-2 pathway in the SGC-996 cells. Our data provide evidence that autocrine TNF-α plays a role as a tumor promoter gene in gallbladder cancer cells, possibly by promoting proliferation and invasion through autocrine mechanisms.

Expression of the RIP-1 Gene and its Role in Growth and Invasion of Human Gallbladder Carcinoma

Background and Aim: Receptor interacting protein(RIP)-1 is thought to have a significant role in inflammation signaling pathways; however, the role of RIP-1 in malignant tumors is largely unknown. Methods: The present study examined the functions and underlying mechanisms of RIP-1 in gallbladder cancer in vitro and in vivo. In this study we determined the expression and role of RIP-1 in 60 clinical specimens from patients with gallbladder cancer and 3 gallbladder cancer cell lines. Using siRNA targeting RIP-1, plasmid vectors (phU6-EGFP-puro/siRIP-1) were constructed and transfected into the gallbladder cells to characterize the biological effect of RIP-1. Results: In vitro experiments indicated that silencing of RIP-1 in NOZ cells significantly suppressed growth and invasion. Furthermore, silencing of RIP-1 affected the RIP1-NF-κB/c-jun(AP-1)-VEGF-C pathways in NOZ cells. Silencing of RIP-1 in vivo inhibited tumor growth in a NOZ cell subcutaneous xenograft model. Immunohistochemstry analysis of the tumor in thesubcutaneous xenograft model also suggested that RIP-1 mediates the expression of VEGF-C. Conclusion: We have elucidated therelationship between RIP-1 overexpression and the growth and invasion of gallbladder cancer from clinical specimens using a xenograft model. We provide evidence that a reduction in the expression of RIP-1 in gallbladder cancer cells can exert inhibitory effects on the ability of cells to grow and invade in vitro. Thus, targeting RIP-1may be useful in the treatment of gallbladder cancer.

MicroRNA-183-5p promotes the proliferation, invasion and metastasis of human pancreatic adenocarcinoma cells.

The aim of the current study was to investigate the potential role of microRNA-183-5p (miR-183-5p) in the proliferation, invasion and metastasis of pancreatic cancer, and to identify promising target genes of oncogenic miR-183-5p. Western blotting and quantitative polymerase chain reaction (qPCR) were used to investigate whether these oncogenic microRNAs may be useful as biomarkers in pancreatic carcinoma (PaCa). Potential target genes were verified using miRDB, PicTar and TargetSCAN, and qPCR was used to detect the expression of miR-183 and suppressor of cytokine signaling 6 (SOCS-6; a potential target of miR-183) in PANC-1 PaCa cells and in the HPDE6-C7 pancreatic ductal cell line for comparison. The function of miR-183 in cell proliferation, wound healing, invasion and migration was also investigated using a miR-183 inhibitor. Western blot analysis was used to confirm SOCS-6 as a tumor suppressor and qPCR was used to detect and confirm that this potential target gene is directly regulated by miR-183. The results indicated that the expression of miR-183 in PANC-1 cells was upregulated compared with that in HPDE6-C7 cells, whilst the expression of SOCS-6 was downregulated. SOCS-6 expression was also significantly lower in PaCa tissues compared with that in matched normal pancreatic tissues from PaCa patients. Furthermore, expression of miR-183 was inversely correlated with that of SOCS-6. miR-183 knockdown decreased cell growth and motility in pancreatic cancer cells and significantly increased the expression of SOCS-6. These data suggest that oncogenic miR-183 may be useful as a pancreatic cancer biomarker. In addition, inhibition of miR-183 expression may be beneficial as PaCa treatment. SOCS-6 is a potential target gene of miR-183.

Stable overexpression of arginase I and ornithine transcarbamylase in HepG2 cells improves its ammonia detoxification

HepG2 is an immortalized human hepatoma cell line that has been used for research into bioartificial liver systems. However, a low level of ammonia detoxification is its biggest drawback. In this work, a recombinant HepG2 cell line with stable overexpression of human arginase I (hArgI) and human ornithine transcarbamylase (hOTC), HepG2/(hArgI + hOTC)4, was developed using a eukaryotic dual gene expression vector pBudCE4.1. (1) The hArgI and hOTC enzymatic activity in HepG2/(hArgI + hOTC)4 cells were higher than in the control cells. (2) The ammonia tolerance capacity of HepG2/(hArgI + hOTC)4 cells was three times that of HepG2 cells and 37.5% of that of primary human hepatocytes in cultivation. In the experiment of ammonia detoxification, HepG2/(hArgI + hOTC)4 cells produced 3.1 times more urea (at 180 mM NH4Cl) and 3.1 times more glutamine (at 120 mM NH4Cl and 15 mM glutamate) than HepG2 cells, reaching 63.1% and 36.0% that of primary human hepatocytes, respectively. (3) The hArgI and hOTC overexpression did not influence the growth of HepG2 cells and also promoted the expression of other ammonia detoxification associated proteins including glutamine synthetase (GS), arginase II (ArgII), arginosuccinate synthase (ASS) and arginosuccinate lyase (ASL) in HepG2 cells. This work illustrates that the modification reported here made significant progress in the improvement of HepG2 cell function and the HepG2/(hArgI + hOTC)4 cells will provide a better selection for the application of bioartificial liver system. J. Cell. Biochem. 113: 518–527, 2012.

Inhibition of invasion and metastasis of MHCC97H cells by expression of snake venom cystatin through reduction of proteinases activity and Epithelial-Mesenchymal Transition

Snake venom cystatin (sv-cystatin) is a member of the cystatin family of cysteine protease inhibitors. To further evaluate the possibility of sv-cystatin in cancer therapy, this study examined the effects of sv-cystatin on the invasion and metastasis of liver cancer cells (MHCC97H) in vitro and in vivo as well as the underlying mechanism. sv-cystatin cDNA was transfected into MHCC97H cells and the anti-invasion and antimetastasis effects of sv-cystatin were determined using migration and matrigel invasion assays and a lung-metastasis mice model. The results suggest that sv-cyst clone (sv-cystatin expression in MHCC97H cells) delayed the invasion and metastasis in vitro and in vivo compared to the parental, mock and si-sv-cyst clone cells (inhibited sv-cystatin expression by siRNA). The decreased activities of cathepsin B, MMP-2 and MMP-9 and EMT change index including higher E-cadherin, lower N-cadherin and decreased Twist activity were observed in the sv-cyst clone, which contributes to the change in invasion and metastasis ability of MHCC97H cells. This study provides evidence that expression of the sv-cystatin gene in MHCC97H cells inhibits tumor cell invasion and metastasis through the reduction of the proteinases activity and Epithelial-Mesenchymal Transition (EMT), which might contribute to the anticancer research of the sv-cystatin protein.

Establishment of and Comparison between Orthotopic Xenograft and Subcutaneous Xenograft Models of Gallbladder Carcinoma

BACKGROUND Gallbladder carcinoma (GBC) is the most common carcinoma of the biliary system. Among its research models, orthotopic xenograft models, important research tools, have been rarely reported in the literature however. AIM To explore establishment of an orthotopic xenograft model and to evaluate the advantage and disadvantage as compared with other models. MATERIALS AND METHODS Subcutaneous xenograft and orthotopic xenograft models of gallbladder carcinoma in nude mice were established and compared with human gallbladder carcinomas. RESULTS For the orthotopic xenograft model and clinical gallbladder carcinomas, the lymph node metastatic rates were 69.2% and 53.3% (p>0.05); ascites generation rates, 38.5% and 11.7%(p<0.05); liver invasive rates, 100% and 61.7%(p<0.05); and lymphatic vessel densities (LVD), 10.4 ± 3.02 and 8.77 ± 2.92 (p>0.05), respectively. In the subcutaneous xenograft model, no evidence of ascites generation, lymph node metastasis and liver metastasis were found, and its LVD was lower (4.56 ± 1.53, p<0.05). CONCLUSIONS Compared with the subcutaneous xenograft model, the orthotopic xenograft model better simulates clinical gallbladder carcinoma in terms of metastasis and invasion, which may be attributed to the difference in microenvironment and LVD.