Galectin-1 is implicated in making tumor cells immune privileged, in part by regulating the survival of infiltrating T cells. Galectin-1 is strongly expressed in activated pancreatic stellate cells (PSCs); however, whether this is linked to tumor cell immune escape in pancreatic cancer is unknown. Galectin-1 was knocked down in PSCs isolated from pancreatic tissues using small interfering RNA (siRNA), or overexpressed using recombinant lentiviruses, and the PSCs were cocultured with T cells. CD31 , CD4 1 and CD8 1 T cell apoptosis was detected by flow cytometry; T cell IL-2, IL-4, IL-5 and INF-c production levels were quantified using ELISA. Immunohistochemical analysis showed increased numbers of PSCs expressed Galectin-1 (p < 0.01) and pancreatic cancers had increased CD3 1 T cell densities (p < 0.01) compared to normal pancreas or chronic pancreatitis samples. In coculture experiments, PSCs that overexpressed Galectin-1 induced apoptosis of CD4 1 T cells (p < 0.01) and 05). Supernatants from T cells cocultured with PSCs that overexpressedGalectin-1 contained significantly increased levels of Th2 cytokines (IL-4 and IL-5, p < 0.01) and decreased Th1 cytokines (IL-2 and INF-c, p < 0.01). However, the knockdown of PSC Galectin-1 had the opposite effect on Th1 and Th2 cytokine secretion. Our study suggests that the overexpression of Galectin-1 in PSCs induced T cell apoptosis and Th2 cytokine secretion, which may regulate PSC-dependent immunoprivilege in the pancreatic cancer microenvironment. Galectin-1 may provide a novel candidate target for pancreatic cancer immunotherapy.Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive malignancy, which is resistant to currently available systemic therapies. PDAC has one of the worst prognoses of all human cancers with incidence rates nearly equal to mortality rates. 1 There is evidence that excessive desmoplasia play a crucial role in the aggressive behavior of pancreatic cancer, 2 which impedes effective systemic treatments on a molecular level. Pancreatic stellate cells (PSCs) are stellate-shaped mesenchymal pancreatic cells, which have been identified as important regulators of desmoplasia in PDAC. 3In their quiescent state, PSCs can be identified by the presence of vitamin A-containing lipid droplets in the cytoplasm and the expression of desmin and glial-fibrillary-acidic protein (GFAP). 4 In response to pancreatic damage or stress, PSC are transformed into an activated myofibroblast-like phenotype. Activated PSCs express a-smooth muscle actin (a-SMA), and synthesize excessive amounts of ECM proteins, including Collagen I and III, fibronectin and matrix-degrading enzymes such as MMPs.5-7 Activated PSCs have a variety of cell functions and can promote the proliferation, migration, invasion and metastasis of pancreatic cancer cells; 1,8,9 however, the factors that PSCs secrete to advance pancreatic cancer progression remain largely unknown.Galectin-1, a member of the galectin family of b-galactosidebinding proteins, is a homodimer of 14-kDa subunits pos...

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Hepatocellular carcinoma (HCC) typically relies on angiogenesis for its malignant behavior, including growth and metastasis. Vasohibin 2 (VASH2) was previously identified as an angiogenic factor, but its role in tumorigenesis is unknown. Using quantitative PCR and western blot analyses, we found that VASH2 is overexpressed in HCC cells and tissues. Using chromatin immunoprecipitation, we detected histone modifications at the putative VASH2 promoter, with increased H3K4 trimethylation and H3 acetylation and decreased H3K27 trimethylation, suggesting that epigenetic mechanisms are responsible for the deregulated VASH2 transcription in HCC. Knockdown of VASH2 via siRNA inhibited the proliferation of the hepatoma cell lines by delaying cell cycle progression and increasing apoptosis. Importantly, we found VASH2 secreted in the culture supernatant, and co-expression of its secretory chaperone small vasohibin-binding protein (SVBP) further enhanced VASH2 secretion. The supernatant from HepG2 cells expressing VASH2 enhanced the proliferation, migration and tube formation of human umbilical vein endothelial cells, and knockdown of VASH2 significantly inhibited these effects. In an in vivo study using a nude mouse model, we found that exogenous VASH2 significantly contributed to tumor growth, microvessel density and hemoglobin concentration in the tumors. Further analyses showed that the VASH2-mediated increase in the transcription of fibroblast growth factor-2, vascular endothelial growth factor and vasohibin 1 may be the mechanism underlying these effects. Taken together, these data indicate that VASH2 is abnormally expressed in HCC cells as a result of histone modifications and that VASH2 contributes to the angiogenesis in HCC via an SVBP-mediated paracrine mechanism. These results indicate a novel and important role for VASH2 in HCC angiogenesis and malignant transformation.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most common malignant tumors with poor prognosis due to extremely high malignancy, low rate of eligibility for surgical resection and chemoradiation resistance. Increasing evidence indicate that the interaction between activated pancreatic stellate cells (PSCs) and PDAC cells plays an important role in the development of PDAC. By producing high levels of cytokines, chemotactic factors, growth factors and excessive extracellular matrix (ECM), PSCs create desmoplasia and a hypoxic microenvironment that promote the initiation, development, evasion of immune surveillance, invasion, metastasis and resistance to chemoradiation of PDAC. Therefore, targeting the interaction between PSCs and PDAC cells may represent a novel therapeutic approach to advanced PDAC, especially therapies that target PSCs of the pancreatic tumor microenvironment.Pancreatic ductal adenocarcinoma (PDAC) is the most common and lethal malignant tumors in humans with very poor prognosis, due to a variety of causes including the insidious onset, absence of efficient screening methods for early detection, low rate of surgical resection at the time of clinical presentation and chemoradiation resistance. 1 Although scholars have been committed during the last three decades to studying genetic and/or epigenetic molecular changes of PDAC cells and chemotherapy with a combination of cytotoxic drugs have been implemented, the survival of patients with PDAC has not yet significantly improved.2,3 Until recently, an encouraging FOLFIRINOX scheme was reported to provide a statistically and clinically significant benefit over single-agent gemcitabine in patients with advanced PDAC but Key words: pancreatic ductal adenocarcinoma, pancreatic stellate cells, tumor microenvironment Abbreviations: ADMR: adrenomedullin receptor; AM: adrenomedullin; ATRA: all-trans retinoic acid; CTGF: connective tissue growth factor; DCs: dendritic cells; ECM: extracellular matrix; EGF: epidermal growth factor; EMMPRIN: extracellular matrix metalloproteinase inducer; EMT: epithelial-mesenchymal transition; ET-1: endothelin-1; FGF: fibroblast-growth-factor; GFAP: glial-fibrillary-acidic protein; HGF: hepatocyte growth factor; HPDE: human pancreatic duct epithelial; HSCs: hepatic stellate cells; HUVEC: endothelial cells; IGF-1: insulin-like growth factor-1; IL: interleukin; MMPs: matrix metalloproteinases; NADPH: nicotinamide adenine dinucleotide phosphate; NO: nitric oxide; PAEE: palmitic acid ethyl ester; PCLMs: pancreatic cancer liver metastases; PDAC: pancreatic ductal adenocarcinoma; PDGF: platelet-derived growth factor; PEDF: pigment epithelium-derived factor; PK: prokineticin; PKR: prokineticin receptor; PSCs: pancreatic stellate cells; ROS: oxygen species; Runx-2: Runt-related transcription factor-2; SDF-1: stromal cell-derived factor-1; sFRP4: secreted frizzled-related protein 4; SMO: smoothened; a-SMA: a-smooth muscle actin; SPARC: secreted protein acidic and rich in cysteine; TFF1: trefoil factor 1; TGF-b: transforming gr...

Background:Expression of ABCG2 is normally absent or low in the pancreas, but high in human pancreatic cancer cells. The mechanism by which ABCG2 is altered in human cancers remains unknown.Methods:We investigated ABCG2 expression in four pancreatic cancer cell lines, and used three microRNA (miRNA) target prediction programmes, and information from the existing literature to predict and identify hsa-miR-520h as an miRNA that targets ABCG2. The function of this miRNA was investigated by transient transfection of the pancreatic cancer cell line PANC-1 with oligonucleotides that mimic hsa-miR-520h.Results:Results showed that both mRNA and protein levels of ABCG2 were reduced, indicating that it was a target of hsa-miR-520h. Introduction of hsa-miR-520h mimics into PANC-1 cells also resulted in inhibition of cell migration and invasion, and reduction of side population cells. Cell proliferation, cell cycle progression and apoptosis were not affected.Conclusions:We propose that the effects of hsa-miR-520h may be, at least in part, caused by its regulation of ABCG2. Thus, our findings provide a new insight into the function of miRNA in the regulation of ABCG2 expression in pancreatic cancer. Gene therapy using miRNA mimics may therefore be useful as a pancreatic cancer therapy.

Postoperative chemotherapy for Colorectal cancer (CRC) patients is not all effective and the main reason might lie in cancer stem cells (CSCs). Emerging studies showed that CSCs overexpress some drug-resistance related proteins, which efficiently transport the chemotherapeutics out of cancer cells. Salinomycin, which considered as a novel and an effective anticancer drug, is found to have the ability to kill both CSCs and therapy-resistant cancer cells. To explore the potential mechanisms that salinomycin could specifically target on therapy-resistant cancer cells in colorectal cancers, we firstly obtained cisplatin-resistant (Cisp-resistant) SW620 cells by repeated exposure to 5 μmol/l of cisplatin from an original colorectal cancer cell line. These Cisp-resistant SW620 cells, which maintained a relative quiescent state (G0/G1 arrest) and displayed stem-like signatures (up-regulations of Sox2, Oct4, Nanog, Klf4, Hes1, CD24, CD26, CD44, CD133, CD166, Lgr5, ALDH1A1 and ALDH1A3 mRNA expressions) (p < 0.05), were sensitive to salinomycin (p < 0.05). Salinomycin did not show the influence on the cell cycle of Cisp-resistant SW620 cells (p > 0.05), but could induce cell death process (p < 0.05), with increased levels of LDH release and MDA contents as well as down-regulations of SOD and GSH-PX activities (p < 0.05). Our data also showed that the pro-apoptotic genes (Caspase-3, Caspase-8, Caspase-9 and Bax) were up-regulated and the anti-apoptotic gene Bcl-2 were down-regulated in Cisp-resistant SW620 cells (p < 0.05). Accumulated reactive oxygen species and dysregulation of some apoptosis-related genes might ultimately lead to apoptosis in Cisp-resistant SW620 cells. These findings will provide new clues for novel and selective chemotherapy on cisplatin-resistant colorectal cancer cells.

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