Curcumin inhibits the invasion and migration of pancreatic cancer cells by upregulating TFPI-2 to regulate ERK- and JNK-mediated epithelial-mesenchymal transition.

PURPOSE: Pancreatic cancer (PC) is one of the most deadly human malignancies. Curcumin is a natural polyphenolic compound with wide-ranging pharmacological effects. Growing evidence suggests that curcumin has anticancer activity against PC, but the mechanism remains incompletely elucidated. This study aimed to investigate the effects and mechanisms of curcumin on the invasion and migration of PC cells. METHODS: Effect of curcumin on tissue factor pathway inhibitor (TFPI)-2 mRNA expression in PC cells was initially identified using qRT-PCR. Cytotoxicity of curcumin was assessed with MTT assays and IC50 was calculated. Involvement of ERK and JNK pathways, as well as protein expression of TFPI-2 and epithelial-mesenchymal transition (EMT)-related markers, were detected using immunoblotting. Invasion and migration of PC cells were examined using Transwell assays. TFPI-2 expression was manipulated by transfection with siRNA and shRNA. Rescue assays were used to validate the effect of curcumin on cell invasion and migration via TFPI-2. RESULTS: Curcumin increased the expression of TFPI-2 mRNA and protein in PC cells and attenuated cell invasion and migration. Curcumin also inhibited ERK and JNK pathways and EMT in PC cells. Knockdown of TFPI-2 partially reversed the inhibition of ERK and JNK pathways and EMT by curcumin. Mechanistically, curcumin upregulated TFPI-2, thereby inhibiting the ERK and JNK pathways, leading to the inhibition of EMT in PC cells. CONCLUSION: Collectively, curcumin inhibits ERK- and JNK-mediated EMT through upregulating TFPI-2, which in turn suppresses the migration and invasion of PC cells. These findings provide new insights into the antitumor mechanism of curcumin.

CASC9 potentiates gemcitabine resistance in pancreatic cancer by reciprocally activating NRF2 and the NF-κB signaling pathway.

Gemcitabine resistance is a frequently occurring and intractable obstacle in pancreatic cancer treatment. However, the underlying mechanisms require further investigation. Adaptive regulation of oxidative stress and aberrant activation of the NF-κB signaling pathway are associated with resistance to chemotherapy. Here, we found that gemcitabine upregulated the expression of CASC9 in a dose-dependent manner, partially via induction of reactive oxygen species, whereas inhibition of CASC9 expression enhanced gemcitabine-induced oxidative stress and apoptosis in pancreatic cancer cells. Furthermore, suppression of CASC9 level inhibited the expression of NRF2 and the downstream genes NQO1 and HO-1, and vice versa, indicating that CASC9 forms a positive feedback loop with NRF2 signaling and modulates the level of oxidative stress. Silencing CASC9 attenuated NF-κB pathway activation in pancreatic cancer cells and synergistically enhanced the cytotoxic effect of gemcitabine chemotherapy in vivo. In conclusion, our findings suggest that CASC9 plays a key role in driving resistance to gemcitabine through a reciprocal loop with the NRF2-antioxidant signaling pathway and by activating NF-κB signaling. Our study reveals potential targets that can effectively reverse resistance to gemcitabine chemotherapy.

Effect of Ag-1031 on apoptosis in gastric cancer AGS cells and its effects on the PI3K/AKT/mTOR signaling pathway.

PURPOSE: To investigate the effect of Ag-1031 on apoptosis of gastric cancer AGS cells and the PI3K/AKT/mTOR signaling pathway. METHODS: Gastric cancer cells were treated with different doses of Ag-1031. Cell viability was determined with MTT assay. Apoptosis was analyzed with Hoechst 33342 staining and Annexin V-FITC/PI double staining. The protein expression levels of p-PI3K, p-AKT, p-mTOR, PI3K, AKT and mTOR were assayed with western blotting method. RESULTS: Different doses of Ag-1031 significantly inhibited the proliferation of AGS cells. Moreover, Ag-1031 induced apoptosis,in gastric cancer cells. In addition, Ag-1031 significantly and dose-dependently inhibited the protein expressions of p-PI3K, p-AKT and p-mTOR. However, it had no effect on the protein expressions of PI3K, AKT and mTOR. CONCLUSION: In this study, it was found for the first time that Ag-1031 exerts an anti-tumor effect by induction apoptosis in gastric cancer AGS cells, through a mechanism related to inhibition of the activation of the PI3K/AKT/mTOR signaling pathway.

Prognostic value of matrix metalloproteinase-9 in gastric cancer: a meta-analysis.

BACKGROUND/AIMS: The purpose of this study was to evaluate the effect of matrix metalloproteinase-9 overexpression on clinical outcome of gastric cancer using a meta-analysis. METHODOLOGY: Relevant studies concerning the association between Matrix metalloproteinase-9 expression and survival of patients with gastric cancer were collected from electronic databases. Hazard ratios (HRs) with 95% confidence intervals (Cls) were calculated to estimate the association. Subgroup analysis was calculated to evaluate potential sources of heterogeneity. Besides, we also assessed the relationship between Matrix metalloproteinase-9 level and relevant clinicopathological parameters by estimating the Odds ratios (ORs) with 95% Cls. RESULTS: Ten studies with 1,478 patients were included to perform a meta-analysis of the survival results. Pooled HRs indicated that MMP-9 overexpression had a negative impact on the over survival (OS) of patients with gastric cancer (HR = 1.69, 95% Cl: 1.29-2.23, P = 0.00), without significant heterogeneity (chi2 = 14.17, I2 = 36.5%, P = 0.117). Similarly, high level of MMP-9 tended to be correlated with lymph node metastasis (OR = 1.91, 95% Cl: 1.40-2.59, P < 0.05) and presence of vascular invasion (OR = 2.64, 95% CI: 1.52-4.59, P <0.05). CONCLUSIONS: This meta-analysis shows that Matrix metalloproteinase-9 overexpression is a poor prognostic factor in patients with gastric cancer. However, larger scale and randomized studies are needed to confirm its potential clinical value.

[Expression and clinical significance of AHSG and complement C3 in pancreatic ductal adenocarcinoma].

OBJECTIVE: To analyze serum proteins from pancreatic carcinoma patients, pancreatic benign tumor patients, chronic pancreatitis patients and normal controls to discover potential and specific biomarkers. METHODS: Serum samples were collected from 40 pancreatic carcinoma patients, 10 pancreatic benign tumor patients, 10 chronic pancreatitis patients and 40 cancer-free controls from May 2009 to April 2011. The samples were compared with two-dimensional differential gel electrophoresis (2D-DIGE) and differentially expressed proteins were further identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Then, two up-regulated proteins were further validated by real-time polymerase chain reaction (PCR), Western blot analysis and immunohistochemistry (IHC) from transcriptional and proteinic aspects. RESULTS: We identified 12 differently expressed proteins in pancreatic carcinoma group compared with normal control group, including complement component C3, hemopexin, alpha-2-HS-glycoprotein, apolipoprotein H, serotransferrin, haptoglobin, apolipoprotein E, transthyretin, serum amyloid P-component, vitronectin, prothrombin and isoform 2 of Ig mu chain C region. High level of C3 and AHSG were detected in cancerous tissues by real-time PCR, Western blot and immunohistochemisty. Western blot revealed that gray ratios of C3 and AHSG were 0.11 ± 0.01 and 0.26 ± 0.02 respectively. The Immunohistochemical results showed that positive rate of C3 and AHSG were 72.5% and 82.5% in cancerous group versus 32.5% and 25% respectively in normal control. CONCLUSION: C3 and AHSG may become pancreatic carcinoma-related biomarkers.

Profiling the potential tumor markers of pancreatic ductal adenocarcinoma using 2D-DIGE and MALDI-TOF-MS: up-regulation of Complement C3 and alpha-2-HS-glycoprotein.

BACKGROUND/AIMS: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease with an increasing incidence worldwide. Due to lack of early diagnosis and poor prognosis, it is rather critical to improve the early diagnosis of PDAC. A comparative proteomic method was used to analyze serum proteins to find a new potential specific marker. METHODS: Comparative analysis of the pancreatic peripheral blood protein profiling from 40 pancreatic cancer patients, 10 pancreatic benign tumor patients, 10 chronic pancreatitis patients and 40 cancer-free controls. The samples were carried out by 2D-differential gel electrophoresis (2D-DIGE) and differentially expressed proteins were identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Two up-regulated proteins were further validation by real time RT-PCR, Western blot analysis and Immunohistochemistry (IHC). RESULTS: We identified fourteen differently expressed proteins in PDAC group compared with cancer-free control group, including 9 up-regulation and 5 down-regulation proteins. Increased Complement C3 and alpha-2-HS-glycoprotein (AHSG) were further confirmed by real time RT-PCR, Western blot analysis and IHC. The expressions of Complement C3 and AHSG were higher in PDAC than that in other groups. CONCLUSIONS: These results suggest that Complement C3 and AHSG might be the potential tumor markers in PDAC screening and diagnosis. The finding of inflammation mediated factor Complement C3 revealed that inflammation might be closely related with the occurrence and development process of PDAC.

[Analysis of pancreatic cancer peripheral blood by comparative proteomics].

OBJECTIVE: To identify protein markers for the early diagnosis of pancreatic cancer by a comparative proteomic method. METHODS: Comparative analysis on the pancreatic peripheral blood protein profiling from 20 pancreatic cancer patients, 10 chronic pancreatitis patients and 20 cancer-free controls from May 2007 to September 2008 was carried out by two-dimensional fluorescence electrophoresis (2D-DIGE). Differentially expressed proteins were identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). The significance difference proteins were confirmed by Western-blot. RESULTS: A differentially expressed proteins: complement 3 (C3) was identified. The gray level of C3 in pancreatic cancer tissue, chronic pancreatitis, and normal control group were 1.63 ± 0.28, 0.65 ± 0.13 (t = 11.81, P = 0.00) and 0.88 ± 0.19 (t = 9.93, P = 0.00), respectively. C3 was high expression in pancreatic cancer group compared with normal control group. The expression of C3 was higher in pancreatic cancer group than in chronic pancreatitis group. The high expression of C3 in pancreatic carcinoma was confirmed by Western blot. CONCLUSIONS: 2D-DIGE and MALDI-TOF-MS technology is a quick, easy and practical method to screen for specific biomarkers in serum of patients with pancreatic carcinoma. The identified protein C3 in this study may be as specific serum biomarkers of pancreatic carcinoma.

Role of endoscopic ultrasound in the evaluation of unexplained extrahepatic bile duct dilatation.

OBJECTIVE: This study was performed to assess the diagnostic performance of endoscopic ultrasonography (EUS) in patients with extrahepatic bile duct (EBD) dilatation and develop a novel model incorporating EUS-based signature with clinical parameters for distinguishing the malignant dilation of EBD. METHODS: The EUS data and clinical parameters of the patients were collected and analyzed retrospectively. First, we evaluated the diagnostic performance of EUS in detecting the cause of EBD dilatation. Then, we performed univariate and multivariate binary logistic regression analyses based on clinical and EUS features. Finally, a nomogram was established to aid in distinguishing between malignant dilation and noncalculous benign dilatation of EBD in patients. RESULTS: A total of 184 patients were enrolled. For the diagnosis of malignant dilation, EUS achieved an accuracy of 90.76%, sensitivity of 85.96%, and specificity of 92.91%. For the diagnosis of calculous dilation, EUS achieved an accuracy of 100%, sensitivity of 100%, and specificity of 100%. For the diagnosis of noncalculous benign dilatation, EUS achieved an accuracy of 90.76%, sensitivity of 90.90%, and specificity of 90.58%. Multivariable logistic regression analyses indicated that abnormal liver function test, elevated tumor markers, and EUS findings were the well-diagnostic factors of malignant EBD dilation. The nomogram established by these factors showed good calibration and discrimination. CONCLUSION: EUS is a useful examinational modality in the work-up of EBD dilatation. In combination with abnormal liver function test and elevated tumor markers, EUS may provide additional information for the detection of malignant dilation of EBD and should be further investigated.

N6 -methyladenosine RNA demethylase FTO regulates extracellular matrix-related genes and promotes pancreatic cancer cell migration and invasion.

Pancreatic cancer (PC) is a deadly disease, and its post-transcriptional gene regulation mechanism remains unclear. The abundant extracellular matrix (ECM) in PC plays an important role in tumor progression. This study is the first to focus on the role of N6 -methyladenosine (m6 A) RNA methylation, an emerging post-transcriptional regulatory mechanism, in the regulation of the ECM in PC. Here, we found that ADAMTS2, COL12A1, and THBS2 were associated with the prognosis of PC by comprehensive analysis of differentially expressed genes from two independent GEO expression profile datasets and m6 A-related genes in RMVar database (PAAD). GO and KEGG enrichment analysis found that these m6 A-related targets are chiefly functionally concentrated in the ECM region and participate in ECM signal transduction. Correlation analysis revealed that these genes can be regulated by the demethylase FTO. Cell biology function assays showed that knockdown of FTO-inhibited PC cell abilities to migrate and invade in vitro. qRT-PCR and MeRIP experiments showed that after knockdown of FTO, the mRNA levels of ADAMTS2, COL12A1, and THBS2 and their m6 A modification levels were significantly reduced. These results indicate that m6 A RNA demethylation is associated with the regulation of ECM in PC. In conclusion, m6 A RNA demethylase FTO regulates ECM-related genes and promotes PC cell abilities to migrate and invade, our work provides a new perspective on the molecular mechanism of PC progression.

Long non­coding RNA 01614 hyperactivates WNT/ß­catenin signaling to promote pancreatic cancer progression by suppressing GSK­3ß.

Pancreatic cancer (PC) is a lethal type of cancer for which effective therapies are limited. Long non­coding RNAs (lncRNAs) represent a critical type of regulator category, mediating the tumorigenesis and development of various tumor types, including PC. However, the expression patterns and functions of numerous lncRNAs in PC remain poorly understood. In the present study, linc01614 was identified as a PC­related lncRNA. linc01614 was notably upregulated in PC tissues and cell lines and was associated with the poor disease­free survival of patients with PC according to the analysis of The Cancer Genome Atlas­derived datasets. Functionally, linc01614 knockdown suppressed PC cell proliferation, migration and invasion in vitro, and inhibited tumor proliferation in vitro and in vivo. Mechanistically, linc01614 overexpression stabilized the level of ß­catenin protein to hyperactivate the WNT/ß­catenin signaling pathway in PC cells. Further analyses revealed that linc01614 bound to GSK­3ß and perturbed the interaction between GSK­3ß and AXIN1, thereby preventing the formation of the ß­catenin degradation complex and reducing the degradation of ß­catenin. In summary, the present findings reveal that linc01614 may function as an oncogene and promote the progression of PC and may thus be considered as a potential therapeutic target in the future.

m6A RNA demethylase FTO promotes the growth, migration and invasion of pancreatic cancer cells through inhibiting TFPI-2.

Pancreatic cancer (PC) is one of the most fatal cancers with a very poor prognosis. Here, we found that N6-methyladenosine (m6A) RNA demethylase fat mass and obesity-related protein (FTO) promote the growth, migration and invasion of PC. FTO expression level is increased in human PC and is associated with poor prognosis of PC patients. Knockdown of FTO increases m6A methylation of TFPI-2 mRNA in PC cells, thereby increasing mRNA stability via the m6A reader YTHDF1, resulting in up-regulation of TFPI-2 expression, and inhibits PC proliferation, colony formation, sphere formation, migration and invasion in vitro, as well as tumour growth in vivo. Rescue assay further confirms that FTO facilitates cancer progression by reducing the expression of TFPI-2. Mechanistically, FTO promotes the progression of PC at least partially through reducing m6A/YTHDF1 mediated TFPI-2 mRNA stability. Our findings reveal that FTO, as an m6A demethylase, plays a critical role in promoting PC growth, migration and invasion, suggesting that FTO may be a potential therapeutic target for treating PC.

On-line two-dimensional countercurrent chromatography×high performance liquid chromatography system with a novel fragmentary dilution and turbulent mixing interface for preparation of coumarins from Cnidium monnieri.

This study describes a novel on-line two-dimensional countercurrent chromatography×high performance liquid chromatography (2D CCC×HPLC) system for one-step preparative isolation of coumarins from the fruits of Cnidium monnieri. An optimal biphasic solvent system composed of n-heptane/acetone/water (31:50:19, v/v) with suitable Kd values and a higher retention of the stationary phase was chosen to separate target compounds. In order to address the solvent incompatibility problem between CCC and RP-HPLC, a novel fragmentary dilution and turbulent mixing (FD-TM) interface was successfully developed. In detail, the eluent from the first dimensional CCC column was divided into fractions to form 'sample-dilution' stripes in the two switching sample loops, by the dilution water from the makeup pump. Following this, a long, thin tube was applied to mix the CCC eluent with water by in-tube turbulence, to reduce the solvent effect. Each CCC fraction was alternately trapped on the two holding columns for further preparative HPLC separation. This nationally designed FD-TM strategy effectively reduced post-column pressure and allowed a higher water dilution ratio at the post end of CCC, leading to improved sample recovery and a robust 2D CCC×HPLC isolation system. As a result, in a single 2D separation run (6.5h), eight target compounds (1-8) were isolated from 0.5g crude extract of C. monnieri, in overall yields of 1.3, 2.0, 0.5, 0.5, 0.8, 1.5, 8.2, and 15.0%, with HPLC purity of 90.1, 91.1, 94.7, 99.1, 99.2, 98.2, 97.9, and 91.9%, respectively. We anticipate that this improved 2D CCC×HPLC system, based on the novel FD-TM interface, has broad application for simultaneous isolation and purification of multiple components from other complex plant-derived natural products.

Online polar two phase countercurrent chromatography×high performance liquid chromatography for preparative isolation of polar polyphenols from tea extract in a single step.

Herein, we report an on-line two-dimensional system constructed by counter-current chromatography (CCC) coupling with preparative high-performance liquid chromatography (prep-HPLC) for the separation and purification of polar natural products. The CCC was used as the first dimensional isolation column, where an environmental friendly polar two-phase solvent system of isopropanol and 16% sodium chloride aqueous solution (1:1.2, v/v) was introduced for low toxicity and favorable resolution. In addition, by applying the stop-and-go flow technique, effluents pre-fractionated by CCC was further purified by a preparative column packed with octadecyl silane (ODS) as the second dimension. The interface between the two dimensions was comprised of a 6-port switching valve and an electronically controlled 2-position 10-port switching valve connected with two equivalent holding columns. To be highlighted here, this rationally designed interface for the purpose of smooth desalination, absorption and desorption, successfully solved the solvent compatibility problem between the two dimensional separation systems. The present integrated system was successfully applied in a one-step preparative separation and identification of 10 pure compounds from the water extracts of Tieguanyin tea (Chinese oolong tea). In short, all the results demonstrated that the on-line 2D CCC×LC method is an efficient and green approach for harvesting polar targets in a single step, which showed great promise in drug discovery.

Expression and clinical significance of complement C3, complement C4b1 and apolipoprotein E in pancreatic cancer.

Pancreatic cancer (PC) remains a devastating disease with a five-year survival rate of <5%. The difficulty in making an early diagnosis and the frequent occurrence of metastasis are important reasons for this poor prognosis. In China, the incidence of PC has been increasing steadily. Therefore, the present study aimed to identify effective markers in the early and advanced stages of PC. The expression levels of complement C3, complement C4b1 and apolipoprotein E (ApoE) in the various stages of PC were assessed by immunohistochemistry, RT-PCR and western blotting. Additionally, the statistical significance of the results was analyzed. The expression levels of complement C3, complement C4b1 and apoE were higher in PC compared with normal pancreatic tissues. No correlations were observed between complement C3 and tumor TNM staging or lymph node metastasis. However, complement C4b1 and apoE were markedly correlated with tumor TNM staging and lymph node metastasis. Complement C3 may be used as a marker for the diagnosis of early-stage PC, while complement C4b1 and apoE are closely correlated with tumor development, reflecting the biological behavior of PC, and thus may be used as diagnostic markers of advanced PC.

Expression and clinical significance of apolipoprotein E in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer with a poor prognosis. Our previous proteomic analysis found apolipoprotein E (ApoE) protein to be up-regulated in the sera of patients with PDAC. In this study, we sought to confirm this finding and investigate the relationship between ApoE and PDAC. We measured ApoE expression in tissues from PDAC patients and normal controls (NC) by real-time PCR, western blot, and immunohistochemistry. Enzyme-linked immunosorbent assay (ELISA) was applied to measure the levels of ApoE and carbohydrate antigen 19-9 (CA19-9) in the sera from patients with PDAC and NC. Real-time PCR and western blots showed that the ApoE mRNA and protein levels were up-regulated in PDAC tissues. The immunohistochemical results revealed that overexpression of ApoE was detected in 43 of 55 (78.2 %) PDAC cases and 3 of 20 (15 %) NC. High levels of ApoE were more likely in PDAC patients with advanced T status and TNM stages (p = 0.023 and p = 0.018, respectively). The ELISA results also confirmed that ApoE levels were elevated in the sera of PDAC patients. The sensitivity and specificity for distinguishing PDAC from NC were 76.2 and 71.4 %, respectively, for ApoE, 66.7 and 85.7 %, respectively, for CA19-9, and 81.0 and 85.7 %, respectively, for their combination. These results suggest that ApoE may be a potential PDAC-related biomarker and alone or in combination with other markers may provide additional information for the diagnosis and clinical management of PDAC.

Identification and verification of transthyretin as a potential biomarker for pancreatic ductal adenocarcinoma.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide and is difficult to detect at its early stages when treatment is most effective. Therefore, we performed a comparative proteomic study to identify new biomarkers for the detection of PDAC. METHODS: Serum samples from patients with PDAC, chronic pancreatitis and normal controls were compared using two-dimensional difference gel electrophoresis (2D-DIGE). Differentially expressed separated proteins were subsequently identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF-MS). Then, transthyretin (TTR), one of the differentially expressed proteins, was validated through real-time PCR, western blot and immunohistochemistry. Finally, enzyme-linked immunosorbent assays (ELISA) were employed to confirm the levels of transthyretin in the sera. RESULTS: A total of 21 protein spots showed greater than 1.5-fold changes in expression level in the sera from PDAC patients compared with the normal controls. Among the identified proteins, validation experiments verified the differential expression of transthyretin in PDAC tissue, confirming the proteomic data showing that transthyretin was significantly elevated in patients with PDAC. The ELISA results revealed that the sensitivity and specificity for TTR and CA19-9 in distinguishing PDAC patients from normal individuals were 90.5, 47.6, 66.7 and 85.7 %, respectively, and 81.0 and 85.7 % for their combination. CONCLUSIONS: These results suggest that the level of transthyretin is elevated in patients with PDAC. In combination with CA19-9, transthyretin may provide additional information for the detection of PDAC and should be further investigated.