Zinc is an essential trace element and catalytic/structural component used by many metalloenzymes and transcription factors. Recent studies indicate a possible correlation of zinc levels with the cancer risk; however, the exact role of zinc and zinc transporters in cancer progression is unknown. We have observed that a zinc transporter, ZIP4 (SLC39A4), was substantially overexpressed in 16 of 17 (94%) clinical pancreatic adenocarcinoma specimens compared with the surrounding normal tissues, and ZIP4 mRNA expression was significantly higher in human pancreatic cancer cells than human pancreatic ductal epithelium (HPDE) cells. This indicates that aberrant ZIP4 up-regulation may contribute to the pancreatic cancer pathogenesis and progression. We studied the effects of ZIP4 overexpression in pancreatic cancer cell proliferation in vitro and pancreatic cancer progression in vivo. We found that forced expression of ZIP4 increased intracellular zinc levels, increased cell proliferation by 2-fold in vitro, and significantly increased tumor volume by 13-fold in the nude mice model with s.c. xenograft compared with the control cells. In the orthotopic nude mice model, overexpression of ZIP4 not only increased the primary tumor weight (7.2-fold), it also increased the peritoneal dissemination and ascites incidence. Moreover, increased cell proliferation and higher zinc content were also observed in the tumor tissues that overexpressed ZIP4. These data reveal an important outcome of aberrant ZIP4 expression in contributing to pancreatic cancer pathogenesis and progression. It may suggest a therapeutic strategy whereby ZIP4 is targeted to control pancreatic cancer growth.cell proliferation ͉ tumor progression ͉ zinc uptake

Given the high fatality rate of pancreatic cancer, an effective treatment for this devastating disease is urgently needed. We have shown that mesothelin expression was higher in human pancreatic cancer cells than in human pancreatic duct epithelial cells, and mesothelin mRNA was substantially overexpressed in 18 of 21 (86%) clinical pancreatic adenocarcinoma specimens when compared with the surrounding normal tissues. However, the biological functions of mesothelin in tumor progression are not clearly understood. Here we studied the effects of mesothelin overexpression in pancreatic cancer cell proliferation and migration in vitro and pancreatic cancer progression in vivo. We found that forced expression of mesothelin significantly increased tumor cell proliferation and migration by 90% and 300%, respectively, and increased tumor volume by 4-fold in the nude mice xenograft model when compared with the vector control cell line. Silencing of mesothelin inhibited cell proliferation and migration in pancreatic cancer cells and ablated tumor progression in vivo. Vaccination with chimeric virus-like particles that contain human mesothelin substantially inhibited tumor progression in C57BL/6J mice. The increases in mesothelin-specific antibodies and CTL activity and the decrease in regulatory T cells correlated with reduced tumor progression and prolonged survival. This study revealed novel functions of mesothelin and suggested a new therapeutic vaccine strategy whereby mesothelin is targeted to control pancreatic cancer progression. [Mol Cancer Ther 2008;7(2):286 -96]

Baylor College and Medicine, with D.J.T. as inventor, has filed 19 patents covering the use of TTI-101, a small-molecule inhibitor of STAT3 cited in this review. These patents are exclusively licensed to Tvardi Therapeutics, which was founded and is co-owned by D.J.T.

BACKGROUNDAlthough overexpression of cyclophilin A (CypA) is associated with several types of cancer, its role in pancreatic cancer has not been studied. In this study the expression of CypA and its receptor CD147 on pancreatic cancer was determined as well as the effect of exogenous CypA on pancreatic cancer cell proliferation.METHODSThe expression of CypA and CD147 in human pancreatic cancer cell lines and tissues was determined with real‐time reverse transcriptase polymerase chain reaction (RT‐PCR), Western blot, and immunostaining. Cell proliferation in response to CypA was performed by [3H]thymidine incorporation assay. Phosphorylation of MAPK and cytokine secretion profiles in pancreatic cancer cells were determined by using the Bio‐Plex phosphoprotein assay and cytokine assay.RESULTSPancreatic cancer cell lines expressed significantly higher levels of CypA and CD147 than normal human pancreatic ductal epithelium (HPDE) cells. Expression of CypA and CD147 was also substantially higher in human pancreatic adenocarcinoma tissues than those in normal pancreatic tissues. Addition of exogenous CypA significantly stimulated pancreatic cancer cell proliferation in a dose‐dependent manner and this effect was effectively blocked by pretreatment with anti‐CD147 antibody. In addition, CypA activated ERK1/2 and p38 MAPK signaling pathways and increased the secretion of 2 key cytokines IL‐5 and IL‐17 in Panc‐1 cells.CONCLUSIONSThe expression of CypA and CD147 was significantly increased in both pancreatic cancer cell lines and tissues. Exogenous CypA promotes pancreatic cancer cell growth, which may be mediated through the interaction with CD147 and the activation of ERK1/2 and p38 MAPKs. Cancer 2006. © 2006 American Cancer Society.

Analysis of the human genome indicated that a large fraction of the genome sequences are RNAs that do not encode any proteins, also known as non-coding RNAs. MicroRNAs (miRNAs) are a group of small non-coding RNA molecules, with 20-22-nucleotide (nt) in length, and are predicted to control the activity of approximately 30% of all protein-coding genes in mammals. miRNAs play important roles in many diseases including cancer, cardiovascular disease, and immune disorders. The expression of miRNAs can be regulated by epigenetic modification, DNA copy number change, and genetic mutations. miRNAs can serve as a valuable therapeutic target for a large number of diseases. For miRNAs with oncogenic capabilities, potential therapies include miRNA silencing, antisense blocking, and miRNA modifications. For miRNAs with tumor suppression functions, overexpression of those miRNAs might be a useful strategy to inhibit tumor growth. In this review, we discuss the current progress of miRNA research, regulation of miRNA expression, prediction of miRNA targets, and regulatory role of miRNAs in human physiology and diseases, with a specific focus on miRNAs in pancreatic cancer, liver cancer, colon rectal cancer, cardiovascular disease, immune system, and infectious disease. This review provides valuable information for clinicians and researchers who want to recognize the newest advances in this new field and identify possible lines of investigation in miRNAs as important mediators in human physiology and diseases.

Signal transducer and activator of transcription (STAT) 3 plays a central role in the host response to injury. It is activated rapidly within cells by many cytokines, most notably those in the IL-6 family, leading to pro-proliferative and pro-survival programs that assist the host in regaining homeostasis. With persistent activation, however, chronic inflammation and fibrosis ensue, leading to a number of debilitating diseases. This review summarizes advances in our understanding of the role of STAT3 and its targeting in diseases marked by chronic inflammation and/or fibrosis with a focus on those with the largest unmet medical need.

BackgroundPrevious studies showed that mesothelin (MSLN) plays important roles in survival of pancreatic cancer (PC) cells under anchorage dependent/independent conditions as well as resistance to chemotherapy. The recent success of intratumorally-injected adeno-encoded, chemo/radiation-inducible-promoter driven hTNF-α, (TNFerade) + gemcitabine in pre-clinical models of PC have renewed interest in use of TNF-α as a therapeutic component. To help find additional factors which might affect the therapy, we examined the resistance of MSLN-overexpressing pancreatic cancer cell lines to TNF-α-induced growth inhibition/apoptosis.MethodsStable MSLN overexpressing MIA PaCa-2 cells (MIA-MSLN), stable MSLN-silenced AsPC-1 cells (AsPC-shMSLN) and other pancreatic cells (MIA-PaCa2, Panc 28, Capan-1, BxPC3, PL 45, Hs 766T, AsPC-1, Capan-2, Panc 48) were used. NF-κB activation was examined by western blots and luciferase reporter assay. TNF-α induced growth inhibition/apoptosis was measured by MTT, TUNEL assay and caspase activation. IL-6 was measured using luminex based assay.ResultsCompared to low endogenous MSLN-expressing MIA PaCa-2 and Panc 28 cells, high endogenous MSLN-expressing Capan-1, BxPC3, PL 45, Hs 766T, AsPC-1, Capan-2, Panc 48 cells were resistant to TNF-α induced growth inhibition. Stable MSLN overexpressing MIA-PaCa2 cells (MIA-MSLN) were resistant to TNF-α-induced apoptosis while stable MSLN-silenced AsPC1 cells (AsPC-shMSLN) were sensitive. Interestingly, TNF-α-treated MIA-MSLN cells showed increased cell cycle progression and cyclin A induction, both of which were reversed by caspase inhibition. We further found that MIA-MSLN cells showed increased expression of anti-apoptotic Bcl-XL and Mcl-1; deactivated (p-Ser75) BAD, and activated (p-Ser70) Bcl-2. Constitutively activated NF-κB and Akt were evident in MIA-MSLN cells that could be suppressed by MSLN siRNA with a resultant increase in sensitivity of TNF-α induced apoptosis. Blocking NF-κB using IKK inhibitor wedelolactone also increased sensitivity to TNF-α-mediated cytotoxicity with concomitant decrease in Mcl-1. Blocking Akt using PI3K inhibitor also had a likewise effect presumably affecting cell cycle. MIA-MSLN cells produced increased IL-6 and were increased furthermore by TNF-α treatment. SiRNA-silencing of IL-6 increased TNF-α sensitivity of MIA-MSLN cells.ConclusionsOur study delineates a MSLN-Akt-NF-κB-IL-6-Mcl-1 survival axis that may be operative in PC cells, and might help cancer cells' survival in the highly inflammatory milieu evident in PC. Further, for the success of TNFerade + gemcitabine to be successful, we feel the simultaneous inhibition of components of this axis is also essential.

Signal transducer and activator of transcription (STAT) 3 regulates many cardinal features of cancer including cancer cell growth, apoptosis resistance, DNA damage response, metastasis, immune escape, tumor angiogenesis, the Warburg effect, and oncogene addiction and has been validated as a drug target for cancer therapy. Several strategies have been employed to identify agents that target Stat3 in breast cancer but none has yet entered into clinical use. We used a high-throughput fluorescence microscopy search strategy to identify compounds in a drug-repositioning library (Prestwick library) that block ligand-induced nuclear translocation of Stat3 and identified piperlongumine (PL), a natural product isolated from the fruit of the pepper Piper longum. Piperlongumine inhibited Stat3 nuclear translocation, inhibited ligand-induced and constitutive Stat3 phosphorylation, and modulated expression of multiple Stat3-regulated genes. Surface plasmon resonance assay revealed that piperlongumine directly inhibited binding of Stat3 to its phosphotyrosyl (pY) peptide ligand. Phosphoprotein antibody array analysis revealed that PL does not modulate kinases known to activate Stat3 such as JAKs, Src kinase family members, or RTKs. PL inhibited anchorage-independent and anchorage-dependent growth of multiple breast cancer cell lines having increased pStat3 or total Stat3, and induced apoptosis. PL also inhibited mammosphere formation by tumor cells from patient derived xenografts (PDX). PL’s anti-tumorigenic function was causally linked to its Stat3-inhibitory effect. PL was non-toxic in mice up to a dose of 30 mg/Kg/day for 14 days and caused regression of breast cancer cell line xenografts in nude mice. Thus, PL represents a promising new agent for rapid entry into the clinic for use in treating breast cancer, as well as other cancers in which Stat3 plays a role.