Schulze Center for Novel Therapeutics

Rochester, MN, United States

Schulze Center for Novel Therapeutics

Rochester, MN, United States
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Monturiol-Gross L.,University of Costa Rica | Flores-Diaz M.,University of Costa Rica | Campos-Rodriguez D.,University of Costa Rica | Mora R.,University of Costa Rica | And 3 more authors.
Cellular Microbiology | Year: 2014

Clostridium perfringens phospholipase C (CpPLC), also called α-toxin, plays a key role in the pathogenesis of gas gangrene. CpPLC may lead to cell lysis at concentrations that cause extensive degradation of plasma membrane phospholipids. However, at sublytic concentrations it induces cytotoxicity without inducing evident membrane damage. The results of this work demonstrate that CpPLC becomes internalized in cells by a dynamin-dependent mechanism and in a time progressive process: first, CpPLC colocalizes with caveolin both at the plasma membrane and in vesicles, and later it colocalizes with early and late endosomes and lysosomes. Lysosomal damage in the target cells is evident 9h after CpPLC exposure. Our previous work demonstrated that CpPLCinduces ERK1/2 activation, which is involved in its cytotoxic effect. In this work we found that cholesterol sequestration, dynamin inhibition, as well as inhibition of actin polymerization, prevent CpPLC internalization and ERK1/2 activation, involving endocytosis in the signalling events required for CpPLC cytotoxic effect at sublytic concentrations. These results provide new insights about the mode of action of this bacterial phospholipase C, previously considered to act only locally on cell membrane. © 2013 John Wiley & Sons Ltd.

Herreros-Villanueva M.,Schulze Center for Novel Therapeutics | Hijona E.,University of the Basque Country | Cosme A.,University of the Basque Country | Bujanda L.,University of the Basque Country
World Journal of Gastroenterology | Year: 2012

Pancreatic cancer is one of the most lethal of human malignancies ranking 4th among cancer-related death in the western world and in the United States, and potent therapeutic options are lacking. Although during the last few years there have been important advances in the understanding of the molecular events responsible for the development of pancreatic cancer, currently specific mechanisms of treatment resistance remain poorly understood and new effective systemic drugs need to be developed and probed. In vivo models to study pancreatic cancer and approach this issue remain limited and present different molecular features that must be considered in the studies depending on the purpose to fit special research themes. In the last few years, several genetically engineered mouse models of pancreatic exocrine neoplasia have been developed. These models mimic the disease as they reproduce genetic alterations implicated in the progression of pancreatic cancer. Genetic alterations such as activating mutations in KRas, or TGFb and/or inactivation of tumoral suppressors such as p53, INK4A/ARF BRCA2 and Smad4 are the most common drivers to pancreatic carcinogenesis and have been used to create transgenic mice. These mouse models have a spectrum of pathologic changes, from pancreatic intraepithelial neoplasia to lesions that progress histologically culminating in fully invasive and metastatic disease and represent the most useful preclinical model system. These models can characterize the cellular and molecular pathology of pancreatic neoplasia and cancer and constitute the best tool to investigate new therapeutic approaches, chemopreventive and/or anticancer treatments. Here, we review and update the current mouse models that reproduce different stages of human pancreatic ductal adenocarcinoma and will have clinical relevance in future pancreatic cancer developments. © 2012 Baishideng. All rights reserved.

Herreros-Villanueva M.,Schulze Center for Novel Therapeutics | Hijona E.,University of the Basque Country | Cosme A.,University of the Basque Country | Bujanda L.,University of the Basque Country
World Journal of Gastroenterology | Year: 2012

Pancreatic adenocarcinoma is one of the most aggressive human malignancies, ranking 4th among causes for cancer-related death in the Western world including the United States. Surgical resection offers the only chance of cure, but only 15 to 20 percent of cases are potentially resectable at presentation. Different studies demonstrate and confirm that advanced pancreatic cancer is among the most complex cancers to treat and that these tumors are relatively resistant to chemotherapy and radiotherapy. Currently there is no consensus around the world on what constitutes "standard" adjuvant therapy for pancreatic cancer. This controversy derives from several studies, each fraught with its own limitations. Standards of care also vary somewhat with regard to geography and economy, for instance chemo-radiotherapy followed by chemotherapy or vice versa is considered the optimal therapy in North America while chemotherapy alone is the current standard-standard in Europe. Regardless of the efforts in adjuvant and neoadjuvant improved therapy, the major goal to combat pancreatic cancer is to find diagnostic markers, identifying the disease in a pre-metastatic stage and making a curative treatment accessible to more patients. In this review, authors examined the different therapy options for advanced pancreatic patients in recent years and the future directions in adjuvant and neoadjuvant treatments for these patients. © 2012 Baishideng. All rights reserved.

Rhim A.D.,University of Michigan | Rhim A.D.,University of Pennsylvania | Oberstein P.E.,Columbia University | Thomas D.H.,Columbia University | And 14 more authors.
Cancer Cell | Year: 2014

Sonic hedgehog (Shh), a soluble ligand overexpressed by neoplastic cells in pancreatic ductal adenocarcinoma (PDAC), drives formation of a fibroblast-rich desmoplastic stroma. To better understand its role in malignant progression, we deleted Shh in a well-defined mouse model of PDAC. As predicted, Shh-deficient tumors had reduced stromal content. Surprisingly, such tumors were more aggressive and exhibited undifferentiated histology, increased vascularity, and heightened proliferation-features that were fully recapitulated in control mice treated with a Smoothened inhibitor. Furthermore, administration of VEGFR blocking antibody selectively improved survival of Shh-deficient tumors, indicating that Hedgehog-driven stroma suppresses tumor growth in part by restraining tumor angiogenesis. Together, these data demonstrate that some components of the tumor stroma can act to restrain tumor growth. © 2014 Elsevier Inc.

Joost S.,University of Marburg | Almada L.L.,Schulze Center for Novel Therapeutics | Rohnalter V.,University of Marburg | Holz P.S.,University of Marburg | And 6 more authors.
Cancer Research | Year: 2012

The Hedgehog (HH) pathway has been identified as an important deregulated signal transduction pathway in pancreatic ductal adenocarcinoma (PDAC), a cancer type characterized by a highly metastatic phenotype. In PDAC, the canonical HH pathway activity is restricted to the stromal compartment while HH signaling in the tumor cells is reduced as a consequence of constitutive KRAS activation. Here, we report that in the tumor compartment of PDAC the HH pathway effector transcription factor GLI1 regulates epithelial differentiation. RNAi-mediated knockdown of GLI1 abolished characteristics of epithelial differentiation, increased cell motility, and synergized with TGFβ to induce an epithelial-to-mesenchymal transition (EMT). Notably, EMT conversion in PDAC cells occurred in the absence of induction of SNAIL or SLUG, two canonical inducers of EMT in many other settings. Further mechanistic analysis revealed that GLI1 directly regulated the transcription of E-cadherin, a key determinant of epithelial tissue organization. Collectively, our findings identify GLI1 as an important positive regulator of epithelial differentiation, and they offer an explanation for how decreased levels of GLI1 are likely to contribute to the highly metastatic phenotype of PDAC. ©2011 AACR.

O'Hara S.P.,Miles and Shirley Fiterman Center for Digestive Diseases | Splinter P.L.,Miles and Shirley Fiterman Center for Digestive Diseases | Gajdos G.B.,Miles and Shirley Fiterman Center for Digestive Diseases | Trussoni C.E.,Miles and Shirley Fiterman Center for Digestive Diseases | And 4 more authors.
Journal of Biological Chemistry | Year: 2010

MicroRNAs, central players of numerous cellular processes, regulate mRNA stability or translational efficiency. Although these molecular events are established, the mechanisms regulating microRNA function and expression remain largely unknown. The microRNA let-7i regulates Toll-like receptor 4 expression. Here, we identify a novel transcriptional mechanism induced by the protozoan parasite Cryptosporidium parvum and Gram(-) bacteria-derived lipopolysaccharide (LPS) mediating let-7i promoter silencing in human biliary epithelial cells (cholangiocytes). Using cultured cholangiocytes, we show that microbial stimulus decreased let-7i expression, and promoter activity. Analysis of the mechanism revealed that microbial infection promotes the formation of a NFκB p50-C/EBPβ silencer complex in the regulatory sequence. Chromatin immunoprecipitation assays (ChIP) demonstrated that the repressor complex binds to the let-7i promoter following microbial stimulus and promotes histone-H3 deacetylation. Our results provide a novel mechanism of transcriptional regulation of cholangiocyte let-7i expression following microbial insult, a process with potential implications for epithelial innate immune responses in general. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

Baumgart S.,University of Marburg | Ellenrieder V.,University of Marburg | Fernandez-Zapico M.E.,Schulze Center for Novel Therapeutics
Gut | Year: 2013

Transcription factors are proteins that regulate gene expression by modulating the synthesis of messenger RNA. Since this process is often one dominant control point in the production of many proteins, transcription factors represent the key regulators of numerous cellular functions, including proliferation, differentiation and apoptosis. Pancreatic cancer progression is characterised by activation of inflammatory signalling pathways converging on a limited set of transcription factors that fine-tune gene expression patterns contributing to the growth and maintenance of these tumours. Thus strategies targeting these transcriptional networks activated in pancreatic cancer cells could block the effects of upstream inflammatory responses participating in pancreatic tumorigenesis. The authors review this field of research and summarise current strategies for targeting oncogenic transcription factors and their activating signalling networks in the treatment of pancreatic cancer.

Comba A.,National University of Cordoba | Lin Y.-H.,Schulze Center for Novel Therapeutics | Eynard A.R.,National University of Cordoba | Valentich M.A.,National University of Cordoba | And 2 more authors.
Cancer and Metastasis Reviews | Year: 2011

This article reviews the current knowledge and experimental research about the mechanisms by which fatty acids and their derivatives control specific gene expression involved during carcinogenesis. Changes in dietary fatty acids, specifically the polyunsaturated fatty acids of the ω-3 and ω-6 families and some derived eicosanoids from lipoxygenases, cyclooxygenases, and cytochrome P-450, seem to control the activity of transcription factor families involved in cancer cell proliferation or cell death. Their regulation may be carried out either through direct binding to DNA as peroxisome proliferator-activated receptors or via modulation in an indirect manner of signaling pathway molecules (e.g., protein kinase C) and other transcription factors (nuclear factor kappa B and sterol regulatory element binding protein). Knowledge of the mechanisms by which fatty acids control specific gene expression may identify important risk factors for cancer and provide insight into the development of new therapeutic strategies for a better management of whole body lipid metabolism. © 2011 Springer Science+Business Media, LLC.

Mccleary-Wheeler A.L.,Schulze Center for Novel Therapeutics | Mcwilliams R.,Mayo Medical School | Fernandez-Zapico M.E.,Schulze Center for Novel Therapeutics | Fernandez-Zapico M.E.,Mayo Medical School
Molecular Carcinogenesis | Year: 2012

Pancreatic cancer is a devastating disease with historically limited success in treatment and a poor prognosis. Pancreatic cancer appears to have a progressive pathway of development, initiating from well-described pancreatic intraepithelial neoplasia lesions and concluding with invasive carcinoma. These early lesions have been shown to harbor-specific alterations in signaling pathways that remain throughout this tumorigenesis process. Meanwhile, new alterations occur during this process of disease progression to have a cumulative effect. This series of events not only impacts the epithelial cells comprising the tumor, but they may also affect the surrounding stromal cells. The result is the formation of complex signaling networks of communication between the tumor epithelial cell and the stromal cell compartments to promote a permissive and cooperative environment. This article highlights some of the most common pathway aberrations involved with this disease, and how these may subsequently affect one or both cellular compartments. Consequently, furthering our understanding of these pathways in terms of their function on the tumoral epithelial and stromal compartments may prove to be crucial to the development of targeted and more successful therapies in the future. © 2011 Wiley Periodicals, Inc..

Elsawa S.F.,Schulze Center for Novel Therapeutics | Novak A.J.,Mayo Medical School | Ziesmer S.C.,Mayo Medical School | Almada L.L.,Schulze Center for Novel Therapeutics | And 5 more authors.
Blood | Year: 2011

Although proinflammatory and chemotactic cytokines can profoundly affect the tumor microenvironment, and many of them have been shown to have therapeutic efficacy in preclinical models, the role of these molecules in Waldenström macroglobulinemia (WM) remains poorly understood. In this study, simultaneous analysis of WM patient sera and bone marrow biopsies identified a set of dysregulated cytokines including CCL5, G-CSF, and soluble IL-2 receptor, that were significantly elevated in WM patients whereas IL-8 and EGF levels were significantly lower in these patients compared with healthy controls. Interestingly, CCL5 levels positively correlated with features of disease aggressiveness such as elevated IgM levels and bone marrow involvement. Functional analysis of tumor microenvironment revealed a functional correlation between CCL5 levels and IL-6 levels, a proinflammatory cytokine with an important role in normal and malignant B-cell biology. Furthermore, CCL5 stimulated IL-6 secretion in WM stromal cells resulting in increased IgM secretion by WM malignant cells via the JAK/STAT signaling pathway. Thus, together these results define a novel signaling network in the WM tumor microenvironment controlling IgM secretion and suggest CCL5 as a potential target for the treatment of this disease. © 2011 by The American Society of Hematology.

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