MicroRNA-362 induces cell proliferation and apoptosis resistance in gastric cancer by activation of NF-κB signaling.

BACKGROUND: According to cancer-related microRNA (miRNA) expression microarray research available in public databases, miR-362 expression is elevated in gastric cancer. However, the expression and biological role of miR-362 in gastric progression remain unclear. METHODS: miR-362 expression levels in gastric cancer tissues and cell lines were determined using real-time PCR. The roles of miR-362, in promoting gastric cancer cell proliferation and apoptosis resistance, were assessed by different biological assays, such as colony assay, flow cytometry and TUNEL assay. The effect of miR-362 on NF-κB activation was investigated using the luciferase reporter assay, fluorescent immunostaining. RESULTS: MiR-362 overexpression induced cell proliferation, colony formation, and resistance to cisplatin-induced apoptosis in BGC-823 and SGC-7901 gastric cancer cells. MiR-362 increased NF-κB activity and relative mRNA expression of NF-κB-regulated genes, and induced nuclear translocation of p65. Expression of the tumor suppressor CYLD was inhibited by miR-362 in gastric cancer cells; miR-362 levels were inversely correlated with CYLD expression in gastric cancer tissue. MiR-362 downregulated CYLD expression by binding its 3' untranslated region. NF-κB activation was mechanistically associated with siRNA-mediated downregulation of CYLD. MiR-362 inhibitor reversed all the effects of miR-362. CONCLUSION: The results suggest that miR-362 plays an important role in repressing the tumor suppressor CYLD and present a novel mechanism of miRNA-mediated NF-κB activation in gastric cancer.

Sphingosine kinase 1 is associated with gastric cancer progression and poor survival of patients.

PURPOSE: The present study was to investigate the clinical significance of sphingosine kinase 1 (SPHK1), an oncoenzyme, in the development and progression of gastric cancer. EXPERIMENTAL DESIGN: mRNA and protein levels of SPHK1 expression in normal gastric epithelial cells, gastric cancer cell lines, and paired gastric cancer lesions and the adjacent noncancerous tissues were examined using reverse transcription-PCR and Western blotting. Immunohistochemistry was employed to analyze SPHK1 expression in 175 clinicopathologically characterized gastric cancer cases. Statistical analyses were applied to derive prognostic and diagnostic associations. RESULTS: Levels of SPHK1 mRNA and protein were higher in gastric cancer cell lines than in normal gastric epithelial cells. SPHK1 protein level was up-regulated in gastric cancer lesions compared with that in the paired adjacent noncancerous tissues. Gastric cancer tissues from 115 of 175 (65.7%) patients revealed high level of SPHK1 protein expression in contrast to the undetectable or marginally detectable expression of SPHK1 in the adjacent noncancerous gastric tissues. Significantly different expression levels of SPHK1 were found in patients at different clinical stages (P=0.003), T classification (P=0.035), and M classification (P=0.020). Patients with higher SPHK1 expression had shorter overall survival time, whereas those with lower SPHK1 expression survived longer. Further multivariate analysis suggested that SPHK1 up-regulation was an independent prognostic indicator for the disease. CONCLUSIONS: SPHK1 protein could be a useful marker for the prognosis of gastric cancer. Further study on the potential use of SPHK1 as a therapeutic target is also warranted.

[Decreased macrophage migration inhibitor factor expression up-regulats p27 in hepatocellular carcinoma.].

OBJECTIVES: To observe the expression of macrophage migration inhibition factor (MIF) and p27 in hepatocellular carcinoma tissue, and to investigate the effect of MIF on the expression of p27 in hepatocellular carcinoma (HCC) cells. METHODS: Immunohistochemistry and quantitative RT-PCR were performed to detect the expression of MIF and p27 in HCC tissues and peri-tumor tissues. Specific small interfering RNA (siRNA) targeting MIF gene was chemically synthesized and then transfected at the concentration of 50 nmol/L and 100 nmol/L into PLC cells and Hep3B cells. The mRNA levels of MIF and p27 after MIF siRNA treatment were quantified by real-time RT-PCR. RESULTS: MIF protein and mRNA were over-expressed in the HCC tumor tissues compared to these in the peri-tumor tissues (P less than 0.01). The expression of p27 protein and mRNA was significantly lower in the HCC tumor tissues compared to these in the peri-tumor tissues (P less than 0.01). Compared to normal liver cell line L-02, HCC cell lines expressed higher level of MIF (F=61.036, P less than 0.01) and lower level of p27 (F=529.853, P less than 0.01). In MIF siRNA treated PLC and Hep3B cells, the MIF mRNA was decreased in a dose-dependent manner (F=320.1, P less than 0.01; F=201.2, P less than 0.01). The p27 mRNA was significantly up-regulated in MIF siRNA treated PLC and Hep3B cells compared to control siRNA transfected cells (F=419.4, P less than 0.01; F=459.9, P less than 0.01). CONCLUSIONS: MIF is over-expressed in HCC tumor tissues, and the expression of p27 is repressed by MIF.

[Interference of osteopontin expression inhibits the invasion and metastasis of human hepatocellular carcinoma cell lines].

OBJECTIVE: To investigate the effect of osteopontin (OPN) on the invasion and metastasis of human hapatocellular carcinoma (HCC). METHODS: HCC cell lines (HCC-LM3) were transfected with the chemically synthesized small interfering RNA (siRNA). Real-time PCR and Western blot were used to quantify the mRNA and OPN protein levels. The malignant phenotypes including cellular growth, colony formation and invasion capability of the HCC cells were analyzed. RESULTS: The OPN mRNA and proteins levels were decreased by 75% and 80% in OPN siRNA treated cells. Colony formation and migratory capability were reduced in OPN siRNA treated cells (P < 0.05). CONCLUSION: The specific siRNA is able to reduce the OPN expression at both the mRNA and protein levels and significantly inhibits the invasiveness of HCC cells.

[Influence of liver regeneration after partial hepatectomy on the development of liver metastasis of colon cancer in rats].

OBJECTIVE: To investigate the stimulated effect of liver regeneration on colon cancer cells in remnant liver in rats. METHODS: Rat models with liver metastases or retro-peritoneal metastases of colon cancer were established: animals underwent 37% or 70% liver resection and were compared with a sham laparotomy (15, 25, 15 cases, respectively). Metastases were performed two weeks before resection. Rats were killed 3 weeks after the resection. Total body weight, liver and tumor weights were recorded. The human colon adenocarcinoma cell line Lovo was cultured in the presence of portal serum withdrawn 24 hours and 14 days after partial hepatectomy (PH). DNA synthesis was assessed by flow cytometry analysis for 5-Bromodeoxyuridine (5-BrdU) incorporation. RESULTS: The tumor growth was accelerated in the remnant liver in 70% PH group, but the tumors in 37% PH group and retro-peritoneal site were not influenced by PH. Compared with the control group, after cultured 72 hours with portal serum withdrawn 24 h after PH, a higher 5-BrdU incorporation was found in the Lovo cell lines (P < 0.05), and it reached the peak after 120 hours of culture (P < 0.05). No difference was found between the groups when cultured with the portal serum withdrawn 14 d after PH (P > 0.05). CONCLUSIONS: PH may accelerate the growth of residual microscopic tumor in the liver which contributes to local recurrence. It has no systemic effect and effects on the cancer cell lines in extrahepatic sites. The excision extension is related to the stimulating effects on the cancer cell line, and subtotal hepatectomy is presumably a major determinant.

[Expression of MIF, VEGF and p16 proteins and their correlation with clinicopathological features in cervical cancer].

OBJECTIVE: To investigate the expression of macrophage migration inhibitory factor (MIF), p16 and vascular endothclial growth factor (VEGF) proteins and their relationship with clinicopathological features in cervical cancer. METHODS: Tissue microarray (TMA) and immunohistochemistry were used to detect the expression of MIF, p16 and VEGF proteins in specimens of 10 normal cervical epithelial tissues, 18 cervical intraepithelial neoplasia (CIN II, III) and 31 cervical squamous cell carcinomas. Western blotting was used to detect the expression of MIF, p16 and VEGF proteins in fresh samples of 3 normal cervical epithelial tissues, 3 CIN (III) and 6 cervical squamous cell carcinomas (3 Ib and 3 IIb). RESULTS: Positive expression rates of MIF were 0, 72.2% and 93.5% in the normal, CIN and carcinoma samples, 20.0%, 33.3% and 71.0% for p16, and 10.0%, 44.4% and 74.2% for VEGF, respectively. The expression rates and levels of the three genes were significantly higher in cervical carcinomas than those in CIN. MIF expression was significantly higher in the cases with lower differentiation (17 cases, P = 0.021), and was positively correlated with VEGF expression (P = 0.0045). VEGF expression rate was significantly higher in both cases of poorly differentiated carcinomas and those with stage II b carcinoma or beyond (P = 0.004, P = 0.008). p16 expression was not found to be correlated with tumor differentiation or clinical stage. It was showed by Western blotting that the expression levels of MIF, VEGF and p16 were significantly higher in the carcinomas than those in CIN or normal tissues. CONCLUSION: Expression of MIF, VEGF and p16 are probably involved in the process of cervical carcinogenesis. MIF expression is correlated with tumor differentiation. VEGF expression is correlated with both tumor differentiation and clinical stage.

[Adeno-associated virus mediated tumor necrosis factor related apoptosis inducing ligand gene transfected into hepatocellular carcinoma cells by ultrasound microbubble intensifier: an experimental study].

OBJECTIVE: To evaluate the impact of the recombined adeno-associated virus encoding soluble tumor necrosis factor related apoptosis inducing ligand gene (rAAV-sTRAIL) on proliferation and apoptosis of human hepatocellular carcinoma (HCC) cells, and to investigate the feasibility and efficiency of transfection of rAAV-sTRAIL into human HCC cells by ultrasound microbubble intensifier. METHODS: Human HCC cells of the line HepG2 were transfected with rAAV-sTRAIL or rAAV-sTRAIL combined with microbubble echocontrast agent and appropriate dose of ultrasound irradiation. RT-PCR and Western blotting were used to detect the mRNA and protein expression of sTRAIL gene. MTT method was used to detect the proliferation inhibition rate, and the apoptosis rate of the HepG2 cells was evaluated by flow cytometry. RESULTS: The expression levels of sTRAIL mRNA and protein were higher in the rAAV-TRAIL combined with ultrasound microbubble group than in the rAAV-sTRAIL group (both P < 0.05). The proliferation inhibition rate of the rAAV-TRAIL combined with ultrasound microbubble group was significantly higher than that of the rAAV-sTRAIL group (P < 0.05). The apoptotic effect of the rAAV-TRAIL combined with ultrasound microbubble group was greater than that of the rAAV-sTRAIL group (P < 0.05). CONCLUSION: TRAIL has a potential role to inhibit e proliferation and induce apoptosis of human hepatocellular carcinoma cells. Ultrasound and microbubble echocontrast agent increase the transfection rate of rAAV vector into HCC cells.

[The roles of caveolin-1 and endothelial nitric oxide synthase in the development of portal hypertension in rats with liver cirrhosis].

OBJECTIVE: To study the relationship between the dynamic changes of caveolin-1 with the degrees of liver fibrosis and portal venous pressure (PVP) in the process of rat liver cirrhosis formation induced by dimethylnitrosamine (DMN); also to investigate the mechanisms of caveolin-1 in the regulation of endothelial nitric oxide synthase (eNOS). METHODS: Liver cirrhosis was induced in rats by DMN. The degrees of liver fibrosis and PVP were measured. NOS activity was assessed by citrulline generation. Protein expressions of caveolin-1, eNOS and caveolin-1-eNOS interactions were examined by Western blot and immunoprecipitation, respectively. RESULTS: Four weeks after DMN administration, liver fibrosis was at its peak and then decreased gradually. Immunoprecipitation and Western blot demonstrated that there was enhanced binding of caveolin-1 with eNOS in the process of rat liver cirrhosis. An increase in caveolin-1 expression was detected but the expression of eNOS was lower in cirrhotic tissues than in normal liver tissues. Caveolin-1 protein levels were positively correlated with the degrees of liver fibrosis and the levels of PVP (r=0.967, P < 0.01; r=0.922, P < 0.01, respectively), while NOS catalytic activity was negatively correlated with the degrees of liver fibrosis and levels of PVP (r= 0.973, P < 0.01; r=-0.947, P < 0.01) respectively. CONCLUSIONS: Caveolin-1 upregulation is associated with the development of portal hypertension in liver cirrhosis. Over-expression of caveolin-1 in perisinusoidal cells may promote caveolin-1-eNOS binding and reduce the activity of eNOS.

Upregulation of macrophage migration inhibitory factor promotes tumor metastasis and correlates with poor prognosis of pancreatic ductal adenocarcinoma.

Macrophage migration inhibitory factor (MIF) is a pro­inflammatory cytokine that serves important roles in cancer. MIF overexpression is frequently observed in numerous human cancer types, including pancreatic carcinoma. However, the prognostic value and function of MIF in pancreatic ductal adenocarcinoma (PDAC) have not been fully elucidated. In the present study, upregulation of MIF expression in PDAC tissue compared with adjacent normal tissue was observed. Furthermore, MIF overexpression was identified to be significantly associated with poor survival rates in patients with PDAC. Multivariate Cox regression analysis confirmed that MIF was an independent risk factor for poor survival. Functional analyses demonstrated that MIF knockdown significantly inhibited the proliferation and invasion of pancreatic cancer cells in vitro compared with control cells. IN addition, mechanistic investigations revealed that silencing MIF leads to inhibition of AKT serine/threonine kinase and extracellular­signal­regulated kinase activation, and suppression of cyclin D1 and matrix metalloproteinase­2 expression, which may suppress tumor proliferation and invasion. These results highlight the importance of MIF overexpression in PDAC aggressiveness, and indicate that MIF may be a potential therapeutic target for pancreatic cancer.

Real-time detection of gene expression in cancer cells using molecular beacon imaging: new strategies for cancer research.

Development of novel approaches for quantitative analysis of gene expression in intact tumor cells should provide new means for cancer detection and for studying the response of cancer cells to biological and therapeutic reagents. We developed procedures for detecting the levels of expression of multiple genes in fixed as well as viable cells using molecular beacon imaging technology. We found that simultaneous delivery of molecular beacons targeting survivin and cyclin D1 mRNAs produced strong fluorescence in breast cancer but not in normal breast cells. Importantly, fluorescence intensity correlated well with the level of gene expression in the cells detected by real-time reverse transcription-PCR or Western blot analysis. We further show that molecular beacons can detect changes of survivin gene expression in viable cancer cells following epidermal growth factor stimulation, docetaxel treatment, and overexpression of p53 gene. Thus, molecular beacon imaging is a simple and specific method for detecting gene expression in cancer cells. It has great potential for cancer detection and drug development.

[Correlations of expressions of macrophage migration inhibitor factor and cyclin D1 with tumor size and metastasis of hepatocellular carcinoma].

OBJECTIVE: To explore the possible relationship between the expressions of macrophage migration inhibitor factor (MIF), cyclin D1, cyclin-dependent kinase 4 (CDK4), phosphorylated-retinoblastoma susceptibility gene product Rb protein (phospho-Rb) and the development of hepatocellular carcinoma (HCC). METHODS: 93 HCC tissues and 5 normal liver tissues were used to investigate the expressions of MIF, cyclin D1, CDK4 and phospho-Rb by tissue microarray and immunohistochemistry methods. RESULTS: The expression rates of MIF, cyclin D1, CDK4 and phospho-Rb in the HCC tissues were 71%, 41%, 82% and 14% respectively, and in the normal liver tissues, they were 0%, 0%, 80% and 20% respectively. The expression rates of MIF and cyclin D1 were significantly different between the tumor and the normal liver tissues and the expression rates of CDK4 and phospho-Rb were not significantly different between the tumor and the normal liver tissues. The rate difference (69% versus 48%) of MIF expression between the larger tumors (> 3.5 cm) and the smaller tumors (< 3.5 cm) was of statistical significance (P < 0.01). The expression rate (62%) of cyclin D1 in the tumors with metastasis was significantly higher than the expression rate (35%) in the tumors without metastasis (P < 0.05). MIF expression was positively correlated with cyclin D1 expression in the tumor tissues (P < 0.01). CDK4 and phospho-Rb expressions were not significantly associated with the tumor sizes and metastasis status. CONCLUSION: Our results indicate that MIF and cyclin D1 might be related to the growth and metastasis of HCC.

Small interfering RNA (siRNA)-mediated knockdown of macrophage migration inhibitory factor (MIF) suppressed cyclin D1 expression and hepatocellular carcinoma cell proliferation.

Macrophage migration inhibitory factor (MIF), a proinflammatory and immunoregulatory chemokine, plays important roles in cancer-related biological processes. However, few studies have focused on the clinical relevance of MIF and cyclin D1 expression in hepatocellular carcinoma cells (HCCs). In this study, MIF and cyclin D1 expression levels in HCC tissues and cell lines were significantly upregulated compared with adjacent normal tissues or a normal liver cell line. In HCC specimens, MIF expression positively correlated with cyclin D1 expression. Additionally, MIF and cyclin D1 expression positively correlated with tumor size. MIF knockdown inhibited the proliferation of PLC and HepG2 cells and promoted apoptosis. However, small interfering RNA (siRNA) against MIF did not influence the cell cycle in these cells. In an in vivo xenograft model, MIF knockdown reduced the tumor growth rate. The expression levels of Bcl-2, p-caspase-3, BIM and Bax were upregulated, while the expression levels of cyclin D1, p-Akt and p-ERK were downregulated in MIF-knockdown cells. These findings indicate that MIF siRNA reduces proliferation and increases apoptosis in HCC cells. MIF knockdown inhibits the expression of growth-related proteins and induces the expression of apoptosis-related proteins, supporting a role for MIF as a novel therapeutic target for HCC.

Overexpression of FOXM1 is associated with poor prognosis and clinicopathologic stage of pancreatic ductal adenocarcinoma.

OBJECTIVES: Oncogenic transcription factor forkhead box M1 (FoxM1)-related clinicopathologic characteristics and prognosis of patients with pancreatic ductal adenocarcinoma (PDA) have not been identified. Our aim of studying FoxM1 expression level and survival rate of PDA is to determine whether FoxM1 is a valuable prognostic predictor for PDA patients. METHODS: Expressional levels of FoxM1 mRNA and protein in paired pancreatic cancer lesions and adjacent noncancerous tissues were examined by reverse transcription-polymerase chain reaction and Western blotting. FoxM1 expression was analyzed by immunohistochemistry in 80 patients with PDA. The correlations between FoxM1 immunostaining levels and clinicopathologic factors, as well as the follow-up data of patients, were analyzed statistically. RESULTS: FoxM1 protein and mRNA levels were elevated in pancreatic carcinoma lesions compared with the paired adjacent noncancerous tissues. A high level of expression of FoxM1 was significantly correlated with clinical staging (P = 0.004), lymph node metastasis (P = 0.009), and histological differentiation (P = 0.017). Patients with a higher FoxM1 expression had a significantly shorter survival time than those patients with lower FoxM1 expression (P < 0.001). The multivariate analysis revealed that FoxM1 could serve as an independent factor of poor prognosis. CONCLUSIONS: Our finding indicates that FoxM1 could be used as prognostic molecular marker and therapeutic target for PDA.

Microtubule stability and MAP1B upregulation control neuritogenesis in CAD cells.

AIM: To study the role of microtubule dynamics and microtubule associated protein 1B (MAP1B) in regulation of the neurite extension in CAD catecholaminergic neuronal cell line. METHODS: The neuritogenesis of the CAD cells was abolished by inhibiting microtubule polymerization with nocodazole and by blocking microtubule depolymerization with taxol. MAP1B and tubulin protein expression was detected by Western blot. Immunofluorescent staining of tubulins was observed by fluorescent and confocal microscopy. RESULTS: Microtubule dynamics was essential for CAD neurite extension. Dosage analysis revealed that neurite extension was much more sensitive to nocodazole than to taxol, suggesting a functional requirement for highly active microtubule assembly. A remarkable upregulation of MAP1B protein was detected during neurite extension accompanied with increased microtubule stability. CONCLUSION: Upregulation of MAP1B leads to the stabilization of newly formed microtubules in the developing neurites, which in turn promotes neurite extension.