Current Molecular Medicine - Volume 14, Issue 3, 2014

Aberrant expression of a zinc transporter ZIP4 in pancreatic ductal adenocarcinoma (PDAC) has been shown to contribute to tumor progression and is a potential target for individualized therapy. The overall objective of this study was to determine whether ZIP4 could serve as a novel diagnostic and prognostic marker in human PDAC, and if it can be assessed by minimally invasive sampling using endoscopic ultrasound guided fine needle aspiration (EUS-FNA). Immunohistochemistry was performed to compare ZIP4 expression in the PDAC samples obtained from EUS-FNA and matched surgical tumors (parallel control). Samples were reported by sensitivity, specificity, and predictive values, all with 95% confidence intervals (CI). A total of 23 cases with both FNA and surgical specimens were evaluated. We found that ZIP4 was significantly overexpressed in tumor cells from both sets of samples. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ZIP4 for the diagnosis of PDAC were 72.9%, 72.5%, 76.1%, and 69.0% in EUS-FNA samples, and were 97.9%, 65.4%, 83.9%, and 94.4% in surgical specimens, respectively. The association between the positive rate of ZIP4 expression in FNA and surgical samples is statistically significant (P=0.0216). Both the intensity and percentage of ZIP4 positive cells from the surgical samples correlated significantly with tumor stage (P=0.0025 and P=0.0002). ZIP4 intensity level in FNA samples was significantly associated with tumor differentiation and patient survival. These results indicate that EUS-FNA is capable of non-operative detection of ZIP4, thus offering the potential to direct pre-operative detection and targeted therapy of PDAC.

Accumulating evidence indicates that microRNAs (miRNAs) have great potential as tumor biomarkers and therapeutic agents owing to their functions in tumorigenesis and cancer progression. Aberrant expression of miR-1247 has been found in several cancers and is predicted to play an important role in the pathological processes of pancreatic cancer by miRNA-regulated network analysis. We investigated the expression profile of miR-1247 in pancreatic cancer tissue microarray by in situ hybridization and found that miR-1247 was significantly down-regulated in pancreatic cancer tissues compared to matched benign tissues. High levels of miR-1247 expression were positively correlated with higher overall and recurrence free survival in pancreatic cancer patients, while negatively correlated with tumor grade. Using in vitro and in vivo models, we demonstrated that increased expression of miR-1247 inhibited proliferation, tumorigenicity, colony formation and triggered G0/G1 cell cycle arrest in pancreatic cancer cells. Moreover, we confirmed that neuropilin1 (NRP1) and neuropilin2 (NRP2) are direct targets of miR-1247 by western blot and luciferase reporter assay. Further studies indicated that low dose all trans retinoic acid (ATRA) can induce redifferentiation and restoration of miR-1247 in pancreatic cancer cells. These findings suggest that miR-1247, a novel tumor suppressor, can act as a potential biomarker and therapeutic agent for pancreatic cancer.

Stathmin (STMN) has been known as a p53-regulated protein and has been shown to play an oncogenic role in a range of human malignancies. Paradoxically, most recent studies demonstrated that stathmin has a dual function as both an oncogene and a metastasis suppressor. Stathmin is a member of microtubule dynamic destabilizing proteins and stathmin-regulated microtubule disruption could lead to a variety of cell dysfunctions such as enhanced chronic hypoxia in pancreatic cancer. In this study, we identified that stathmin promotes proliferation of pancreatic cancer cells by an underlying nuclear factor kappa B (Nf-κB) interacting mechanism. In human specimens, stathmin was significantly overexpressed in pancreatic cancer tissues and high expression of stathmin was correlated with vascular emboli (p=0.028), tumor size (p=0.019), and overall survival (p=0.031). Functional assays showed that knockdown of stathmin significantly reduced pancreatic cancer cell viability, colony formation, and arrested the cell cycle at the G2/M phase. Furthermore, silence of stathmin could reduce pancreatic tumor growth in nude mice. For the mechanism, Western blot analyses demonstrated that Nf-κB (p65) was significantly down-regulated when stathmin was silenced. In addition, co-immunoprecipitation (CoIP) assay suggested that stathmin was able to interact with Nf-κB (p65). Our findings indicate that stathmin might play its oncogenic role by an interaction with Nf-κB pathway, which may reveal a novel mechanism to uncover the role of microtubule-destabilizing stathmin in pancreatic cancer environment as well as provide a potential therapeutic strategy for pancreatic cancer.

Objective: To detect mutations of trypsinogen gene (PRSS1) in patients with autoimmune pancreatitis (AIP) and to determine the underlying pathogenesis. Methods: DNA sequencing was used to detect full-length of PRSS1, cystic fibrosis transmembrane conductance regulator (CFTR), and pancreatic secretory trypsin inhibitor (SPINK1) genes mutations in an AIP family and a sporadic case and 520 normal controls. Furthermore, a mutant-expressing system was constructed for functional confirmation. Results: For the first time, we report a deletion mutation at exon 2 of PRSS1 gene (IVS 2 +56_60 del CCCAG) which encoded a truncated PRSS1 protein without trypsinogen activation peptide (TAP). Vitro functional study suggested the identified mutation would result in loss of PRSS1 activity. Mutant trypsinogen activated at a faster rate than wild-type trypsinogen in the autoactivation experiment. Histopathologic examination revealed the ratio of IgG4/IgG-positive plasma cells exceeded 0.455 in pancreas, and the patients responded to glucocorticoids. Conclusion: PRSS1: IVS 2 +56_60 del CCCAG is a noval mutant which may contribute to AIP pathogenesis.

Bone marrow stromal cell antigen 2 (BST-2, also known as tetherin, CD317, or HM1.24) has recently been identified as a host restriction factor against diverse families of enveloped viruses. However, the effects of BST-2 on the life cycle of hepatitis C virus (HCV), an enveloped RNA virus, remain unclear and controversial. Here we demonstrated that human hepatocytes including Huh7.5.1 cells, primary human hepatocytes (PHHs), and HepG2 cells constitutively expressed low to moderate levels of endogenous BST-2 on the cell surface, which could be robustly up-regulated by all three types of interferons (IFNs) such as IFN-α, IFN-γ, and IFN-λ. IFN-α and IFN-γ showed a synergistic effect in induction of BST-2 expression on human hepatocytes. Over-expression of BST-2 by BST-2-expressing vector transfection or up-regulation of BST-2 by IFN stimulation markedly suppressed HCV production, whereas shRNA-mediated depletion of endogenous BST-2 significantly enhanced HCV production in infected Huh7.5.1 cells. IFN-mediated anti-HCV activity was partially but significantly diminished by shRNA-mediated knockdown of BST-2 expression, indicating that BST- 2 upregulation is directly involved in IFN-mediated inhibition of HCV production. We also found that both BST-2 and HCV core co-localized with intracellular lipid droplets (LDs), suggesting that BST-2-HCV interaction may take place around LDs as LDs constitute an important intracellular organelle for HCV assembly and replication. Taken together, our data suggest that BST-2 is a host restriction factor against HCV, and induction of BST-2 in hepatocytes could be one of the mechanisms by which current HCV standard therapy (IFN-α plus ribavirin) achieves a sustained virological response (SVR).

Normal liver has a great potential of regenerative capacity after partial hepatectomy. In clinic, however, most patients receiving partial hepatectomy are usually suffering from chronic liver diseases with severely damaged hepatocyte population. Under these conditions, activation of hepatic progenitor cell (oval cell in rodents) population might be considered as an alternative mean to enhance liver functional recovery. Vitamin K2 has been shown to promote liver functional recovery in patients with liver cirrhosis. In this study, we explored the possibility of vitamin K2 treatment in activating hepatic oval cell for liver regeneration with the classic 2-acetamido-fluorene/partial hepatectomy (2-AAF/PH) model in Sprague-Dawley rats. In 2-AAF/PH animals, vitamin K2 treatment induced a dose-dependent increase of liver regeneration as assessed by the weight ratio of remnant liver versus whole body and by measuring serum albumin level. In parallel, a drastic expansion of oval cell population as assessed by anti-OV6 and anti-CK19 immunostaining was noticed in the periportal zone of the remnant liver. Since matrilin-2 was linked to oval cell proliferation and liver regeneration after partial hepatectomy, we assessed its expression at both the mRNA and protein levels. The results revealed a significant increase after vitamin K2 treatment in parallel with the expansion of oval cell population. Consistently, knocking down matrilin-2 expression in vivo largely reduced vitamin K2-induced liver regeneration and oval cell proliferation in 2-AAF/PH animals. In conclusion, these data suggest that vitamin K2 treatment enhances liver regeneration after partial hepatectomy, which is associated with oval cell expansion and matrilin-2 up-regulation.

The fast and slow skeletal muscle fibers in fish are separated to a much greater degree than in mammals. MyoD is required for the maintenance of normal fiber type balance in muscles. So far, the upstream regulatory factors of MyoD in terms of controlling muscle phenotype are poorly understood. In the present study, we used Siniperca chuatsi as a model system and demonstrated that miR-143 expression was negatively correlated with MyoD expression in the fast and slow muscles of S. chuatsi. The luciferase reporter assay further verified the direct interaction between the miR-143 and MyoD. The miR-143 suppression also led to the significant increase in MyoD and fast myosin heavy chain gene expression in vivo. Taken together, our studies indicated that miRNA participates in controlling the performance of different muscle fiber types in vertebrates.

Diabetic retinopathy (DR) is one of the leading causes of blindness in the working population worldwide. Vascular leakage, angiogenesis and neuronal degeneration are key features of DR. Current effective interventions for DR include treatment of systemic risk factors such as elevated blood glucose, blood pressure and dyslipidemia. Ocular treatments include vascular endothelial growth factor A (VEGF-A) inhibitors, laser photocoagulation and surgery. While anti-VEGF therapy has become as first-line treatment for diabetic macular edema (DME) that causes reduced vision, intravitreal glucocorticoids also have been shown to be efficacious in this situation. It has been reported that all the major pathological processes of DR are susceptible to glucocorticoid treatment. The effects of glucocorticoids on vascular leakage and angiogenesis may be mediated through their well established anti-inflammatory role. Alternatively, glucocorticoids may affect other mechanisms known to be activated in DR. Potential mechanisms for the anti-inflammatory effects of glucocorticoids include blockage of cytokine production and inhibition of leukocyte adhesion induced by VEGF-A. Glucocorticoids decrease the expression of VEGF-A directly, and increase the production, or decrease phosphorylation, of tight junction-associated proteins. Glucocorticoids have also been shown to be neuroprotective, in contrast to VEGF-A inhibitors which animal studies suggest may be neurotoxic. This review outlines the biological properties of synthetic glucocorticoids, with particular emphasis on the potential beneficial effect of combining glucocorticoids with anti-VEGF treatment for DME and DR.

Despite significant efforts to control tuberculosis (TB), the disease remains a major global threat, with an estimated 8.6 million new cases and 1.3 million deaths in 2012 alone. Significant treatment challenges include HIV co-infection, the dramatic rise of multidrug-resistant TB and the vast reservoir of latently infected individuals, who will develop active disease years after the initial infection. The long duration of chemotherapy also remains a major barrier to effective large scale treatment of TB. Significant advances are being made in the development of shorter and effective TB drug regimens and there is growing evidence that host-directed and “non-antimicrobial” pathogen-directed therapies, could serve as novel approaches to enhance TB treatments. This review highlights the rationale for using these therapies and summarizes some of the progress in this field.

Chlamydia trachomatis is the most common sexually transmitted bacterial infection worldwide. The impact of this pathogen on human reproduction has intensified research efforts to better understand chlamydial infection and pathogenesis. Whilst there are animal models available that mimic many aspects of human chlamydial infection, the mouse is regarded as the most practical and widely used of the models. Studies in mice have greatly contributed to our understanding of the host-pathogen interaction and provided an excellent medium for evaluating vaccines. Here we explore the advantages and disadvantages of all animal models of chlamydial genital tract infection, with a focus on the murine model and what we have learnt from it so far.