Fengfei Wang

SDF-1/CXCR4 signaling induces pancreatic cancer cell invasion and epithelial–mesenchymal transition in vitro through non-canonical activation of Hedgehog pathway

In our previous study, we found that blockade of SDF-1/CXCR4 signaling inhibits pancreatic cancer cell migration and invasion in vitro. However, the mechanism governing the downstream regulation of SDF-1/CXCR4-mediated invasion remains unclear. Here we report the role of SDF-1/CXCR4 in pancreatic cancer and the possible mechanism of SDF-1/CXCR4-mediated pancreatic cancer invasion. We show that there is a cross-talk between SDF-1/CXCR4 axis and non-canonical Hedgehog (Hh) pathway in pancreatic cancer. Furthermore, our data demonstrate that the ligand of CXCR4, SDF-1 induces CXCR4-positive pancreatic cancer invasion, epithelial-mesenchymal transition (EMT) process and activates the non-canonical Hh pathway. Moreover, we also demonstrate that the invasion of a pancreatic cancer and EMT resulting from the activation of SDF-1/CXCR4 axis is effectively inhibited by Smoothened (SMO) inhibitor cyclopamine and siRNA specific to Gli-1. Collectively, these data demonstrate that SDF-1/CXCR4 modulates the non-canonical Hh pathway by increasing the transcription of SMO in a ligand-independent manner. Taken together, SDF-1/CXCR4 axis may represent a promising therapeutic target to prevent pancreatic cancer progression.

Stromelysin‐3 suppresses tumor cell apoptosis in a murine model

Stromelysin‐3 (STR‐3) is a matrix metalloproteinase with a unique pattern of expression and substrate specificity. During embryogenesis and remodeling of normal adult tissues, STR‐3 is produced by stromal cells in direct contact with epithelial cells undergoing regional apoptosis and selective cell survival. STR‐3 is also overexpressed by interdigitating stromal cells in primary epithelial malignancies. Although STR‐3 does not degrade classic extracellular matrix components, the enzyme promotes the establishment of local tumors in nude mice by as yet undefined mechanisms. STR‐3 is induced when malignant epithelial cells come into contact with surrounding stromal elements; the active stromal cell‐derived 45 kDa enzyme is subsequently processed to a 35 kDa protein without enzymatic activity. We have generated MCF‐7 transfectants expressing wild type or catalytically inactive 45 kDa STR‐3 (STR‐3wt and STR‐3cat‐) or secreted 35 kDa STR‐3 (35 kDa STR‐3sec) and evaluated their implantation and survival in nude mice. Tumors developed significantly more rapidly in animals receiving STR‐3wt, rather than vector‐only, STR‐3cat‐ or 35 kDa STR‐3sec transfectants. Most importantly, STR‐3wt tumors had a significantly lower percentage of apoptotic cells than tumors derived from vector‐only, STR‐3cat‐ or 35 kDa STR‐3sec transfectants. Taken together, these studies suggest that the active STR‐3 enzyme may increase tumor take by suppressing tumor cell apoptosis and that 45 kDa to 35 kDa STR‐3 processing limits STR‐3 activity at the tumor/stromal interface. Because STR‐3 is secreted as an active enzyme rather than a proform, subsequent 45 kDa to 35 kDa STR‐3 processing may represent a novel mechanism for regulating enzymatic activity. J. Cell. Biochem. 82: 549–555, 2001.

Alterations of TP53 are associated with a poor outcome for patients with hepatocellular carcinoma: evidence from a systematic review and meta-analysis.

BACKGROUND The prognostic significance of p53 aberration in hepatocellular carcinoma (HCC) remains inconclusive. This systematic review and meta-analysis aimed to provide comprehensive evidence on the association of p53 alterations with recurrence-free survival (RFS) and overall survival (OS) in HCC patients. METHODS Systematic literature searches were conducted until July 2010. Meta-analysis was performed to estimate prognostic effects of p53 alterations on patient outcomes in HCC. Sensitivity and subgroup analyses were also conducted in the meta-analysis. RESULTS Thirty-seven studies (7 tumour p53 mutation, 23 tumour p53 expression and 7 serum anti-p53 antibodies) were included in the systematic review and meta-analysis. The average percentages of p53 mutation, p53 expression upregulation and anti-p53 antibody level elevation in HCC patients were 31.5%, 35.0% and 23.8%, respectively. Tumour p53 alterations were associated significantly with poor patient outcomes in HCC: the summary hazard ratio (HR) of mutant p53 versus wild type p53 phenotype was 2.58 [95% confidence interval (CI): 1.96-3.41] for OS and 3.19 [95% CI: 2.21-4.60] for RFS, respectively; and the summary HR of upregulated p53 expression versus low/undetectable p53 expression was 1.68 [95% CI: 1.49-1.90] for OS and 1.89 [95% CI: 1.34-2.66] for RFS, respectively. However, elevated serum anti-p53 antibody was only associated with poor OS in HCC group with a high proportion of (≥ 50%) of hepatitis C virus (HCV) infection [HR: 1.92; 95% CI: 1.30-2.85]. Moreover, sensitivity analyses showed that the results of meta-analyses were not altered. CONCLUSION HCC patients with p53 mutation and upregulated expression in tumour tissue have a shorter OS and RFS than patients with wild type p53 and low/undetectable p53 expression. However, the prognostic value of serum anti-p53 antibody is required to be further examined.

Salinomycin: a novel anti-cancer agent with known anti-coccidial activities.

Salinomycin, traditionally used as an anti-coccidial drug, has recently been shown to possess anti-cancer and anti-cancer stem cell (CSC) effects, as well as activities to overcome multi-drug resistance based on studies using human cancer cell lines, xenograft mice, and in case reports involving cancer patients in pilot clinical trials. Therefore, salinomycin may be considered as a promising novel anti-cancer agent despite its largely unknown mechanism of action. This review summarizes the pharmacologic effects of salinomycin and presents possible mechanisms by which salinomycin exerts its anti-tumorigenic activities. Recent advances and potential complications that might limit the utilization of salinomycin as an anti-cancer and anti-CSC agent are also presented and discussed.

Advances in biomarker research for pancreatic cancer.

Pancreatic cancer (PC) is a leading cause of cancer related deaths in United States. The lack of early symptoms results in latestage detection and a high mortality rate. Currently, the only potentially curative approach for PC is surgical resection, which is often unsuccessful because the invasive and metastatic nature of the tumor masses makes their complete removal difficult. Consequently, patients suffer relapses from remaining cancer stem cells or drug resistance that eventually lead to death. To improve the survival rate, the early detection of PC is critical. Current biomarker research in PC indicates that a serum carbohydrate antigen, CA 19-9, is the only available biomarker with approximately 90% specificity to PC. However, the efficacy of CA 19-9 for assessing prognosis and monitoring patients with PC remains contentious. Thus, advances in technology and the detection of new biomarkers with high specificity to PC are needed to reduce the mortality rate of pancreatic cancer.

Relationship between Neural Alteration and Perineural Invasion in Pancreatic Cancer Patients with Hyperglycemia

Background Patients with higher levels of fasting serum glucose have higher death rates from pancreatic cancer compared to patients with lower levels of fasting serum glucose. However, the reasons have not been studied. The goal of the current study was to examine the neural alterations in pancreatic cancer patients with hyperglycemia and to identify the relationship between the neural alterations and perineural invasion. Methodology/Principal Findings The clinical and pathological features of 61 formalin-fixed pancreatic cancer specimens and 10 normal pancreases as controls were analyzed. Furthermore, the expression of Protein Gene Product 9.5 (PGP9.5), Myelin P0 protein (MPP), NGF, TrkA, and p75 were examined by immunohistochemistry. The median number of nerves, the median area of neural tissue, and the median nerve diameter per 10 mm2 were larger in the hyperglycemia group than those in the euglycemia group (p = 0.007, p = 0.009, and p = 0.004, respectively). The integrated optical density (IOD) of MPP staining was lower in the hyperglycemia group than those in the euglycemia group (p = 0.019), while the expression levels of NGF and p75 were higher in the hyperglycemia group than those in the euglycemia group (p = 0.002, and p = 0.026, respectively). The nerve bundle invasion of pancreatic cancer was more frequent in the hyperglycemia group than in the euglycemia group (p = 0.000). Conclusions/Significance Nerve damage and regeneration occur simultaneously in the tumor microenvironment of pancreatic cancer patients with hyperglycemia; the simultaneous occurrence may aggravate the process of perineural invasion. The abnormal expression of NGF and p75 may also be involved in this process and subsequently lead to a lower rate of curative surgery.

Thalidomide-a notorious sedative to a wonder anticancer drug.

In the past 50 years, thalidomide has undergone a remarkable metamorphosis from a notorious drug inducing birth defects into a highly effective therapy for treating leprosy and multiple myeloma. Today, most notably, thalidomide and its analogs have shown efficacy against a wide variety of diseases, including inflammation and cancer. The mechanism underlying its teratogenicity as well as its anticancer activities has been intensively studied. This review summarizes the biological effects and therapeutic uses of thalidomide and its analogs, and the underlying mechanisms of thalidomides action with a focus on its suppression of tumor growth.

Neurotransmitter substance P mediates pancreatic cancer perineural invasion via NK-1R in cancer cells

Pancreatic cancer significantly affects the quality of life due to the severe abdominal pain. However, the underlying mechanism is not clear. This study aimed to determine the relationship between Substance P (SP) and pancreatic cancer perineural invasion (PNI) as well as the mechanism of SP mediating pancreatic cancer PNI, which causes pain in patients with pancreatic cancer. Human pancreatic cancer cells and newborn dorsal root ganglions (DRG) were used to determine the expression of SP or NK-1R in pancreatic cancer cells and DRGs cells by QT-PCR and Western blotting. The effects of SP on pancreatic cancer cell proliferation and invasion were analyzed using MTT assay and Transwell Matrigel invasion assay, respectively. Alterations in the neurotropism of pancreatic cancer cells were assessed by coculture system, which mimics the interaction of tumor/neuron in vivo. SP is not only widely distributed in the neurite outgrowth from newborn DRGs but also expressed in MIA PaCa-2 and BxPC-3 cells. NK-1R is found to be overexpressed in the pancreatic cancer cell lines examined. SP induces cancer cell proliferation and invasion as well as the expression of matrix metalloproteinase (MMP)-2 in pancreatic cancer cells, and NK-1R antagonists inhibit these effects. Furthermore, SP promotes neurite outgrowth and the migration of pancreatic cancer cell cluster to the DRGs, which is blocked by NK-1R antagonists in the coculture model. Our results suggest that SP plays an important role in the development of pancreatic cancer metastasis and PNI, and blocking the SP/NK-1R signaling system is a novel strategy for the treatment of pancreatic cancer. Mol Cancer Res; 11(3); 294–302. ©2012 AACR.

Hyperglycemia Regulates TXNIP/TRX/ROS Axis via p38 MAPK and ERK Pathways in Pancreatic Cancer

Approximately 85% of pancreatic cancer patients suffer from glucose intolerance or even diabetes because high glucose levels can contribute to oxidative stress which promotes tumor development. As one of the reactive oxygen species (ROS)-regulating factors, thioredoxin-interacting protein (TXNIP), is involved in the maintenance of thioredoxin (TRX)-mediated redox regulation. In this study, we demonstrated that high glucose levels increased the expression of TXNIP in time- and concentration-dependent manners and modulated the activity of TRX and ROS production in pancreatic cancer cells, BxPC-3 and Panc-1. We also found that glucose activated both p38 MAPK and ERK pathways and inhibitors of these pathways impaired the TXNIP/TRX/ROS axis. Knockdown of TXNIP restored TRX activity and decreased ROS production under high glucose conditions. Moreover, we observed that the integrated optical density (IOD) of TXNIP staining as well as the protein and mRNA expression levels of TXNIP were higher in the tumor tissues of pancreatic cancer patients with diabetes. Taken together, these results indicate that hyperglycemia-induced TXNIP expression is involved in diabetes-mediated oxidative stress in pancreatic cancer via p38 MAPK and ERK pathways.

The Activation of β 1 -integrin by Type I Collagen Coupling with the Hedgehog Pathway Promotes the Epithelial-Mesenchymal Transition in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by the excessive deposition of extracellular matrix (ECM), which is thought to contribute to this tumors malignant behavior. However, the detailed mechanism and the contribution of excessive deposition of ECM in PDAC progression remain unclear. A better understanding of the mechanism involved in this process is essential for the design of new effective therapies. In this study, we demonstrated that pancreatic cancer cells exhibited increased proliferation and decreased apoptosis in response to type I collagen. In addition, PDAC cells exposed to type I collagen lost the expression of E-cadherin and increased expression of mesenchymal markers, including N-cadherin and vimentin. This epithelial- mesenchymal transition (EMT) was correlated with enhanced cell migration and invasiveness. Knockdown of β1-integrin abolished the effects induced by type I collagen, and further investigation revealed that type I collagen activates β1-integrin (marked by phosphorylation of β1 integrin downstream effectors, focal adhesion kinase [FAK], AKT, and ERK) accompanied by markedly up-regulation of Gli-1, a component of the Hedgehog (HH) pathway. Knockdown of Gli-1 reversed the effects of type I collagen on PDAC invasion and EMT. These results suggest that there is cross-talk between the β1-integrin signaling pathway and the HH pathway in pancreatic cancer and that activation of the HH pathway plays a key role in the type I collagen-induced effects on pancreatic cancer.