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ABSTRACT: Several pathways are involved in the control of endothelial cell morphology, endothelial permeability and function in order to maintain vascular homeostasis. Here we report that protein kinase N3 (PKN3) appears to play a pivotal role in maintaining endothelial cell morphology, cell-cell junctions and motility. An RNAi-based cell biological approach in cultured human endothelial cells (HUVEC) revealed that knockdown of PKN3 expression gave rise to cells with divergent cell morphology, impaired locomotion, disturbed adherens junctions (AJ) integrity and irregular actin organization. Notably, knockdown of PKN3 cells led to improper stress fiber formation and marked adhesiveness of intercellular adherens junctions when cells became stimulated with the pro-inflammatory cytokine TNF-α. Moreover, TNF-α-induced ICAM-1 expression on the cell surface was reduced in cells with suppressed PKN3 expression. Finally, loss-of-function for PKN3 appeared to affect Pyk2 phosphorylation in endothelial cells. These observations suggest that PKN3 can be considered a novel protein implicated in remodeling the actin-adherens junction, possibly by linking ICAM-1-signaling with actin/AJ dynamics. We propose that loss of PKN3 function and concomitant aberrations in actin rearrangement may attenuate pro-inflammatory activation of endothelial cells.
European journal of cell biology 05/2012; 91(9):694-705. · 3.31 Impact Factor
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Ansgar Santel,
Manuela Aleku,
Nadine Röder,
Kristin Möpert,
Birgit Durieux,
Oliver Janke,
Oliver Keil,
Jens Endruschat,
Sibylle Dames,
Christian Lange,
Mona Eisermann, Kathrin Löffler,
Melanie Fechtner,
Gerald Fisch,
Christiane Vank,
Ute Schaeper,
Klaus Giese,
Jörg Kaufmann
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ABSTRACT: Atu027, a novel RNA interference therapeutic, has been shown to inhibit lymph node metastasis in orthotopic prostate cancer mouse models. The aim of this study is to elucidate the pharmacologic activity of Atu027 in inhibiting hematogenous metastasis to the target organ lung in four different preclinical mouse models.
Atu027 compared with vehicle or control small interfering RNA lipoplexes was tested in two experimental lung metastasis models (Lewis lung carcinoma, B16V) and spontaneous metastasis mouse models (MDA-MB-435, MDA-MB-231, mammary fat pad). Different dosing schedules (repeated low volume tail vein injections) were applied to obtain insight into effective Atu027 treatment. Primary tumor growth and lung metastasis were measured, and tissues were analyzed by immunohistochemistry and histology. In vitro studies in human umbilical vein endothelial cells were carried out to provide an insight into molecular changes on depletion of PKN3, in support of efficacy results.
Intravenous administration of Atu027 prevents pulmonary metastasis. In particular, formation of spontaneous lung metastasis was significantly inhibited in animals with large tumor grafts as well as in mice with resected primary mammary fat pad tumors. In addition, we provide evidence that an increase in VE-cadherin protein levels as a downstream result of PKN3 target gene inhibition may change endothelial function, resulting in reduced colonization and micrometastasis formation.
Atu027 can be considered as a potent drug for preventing lung metastasis formation, which might be suitable for preventing hematogenous metastasis in addition to standard cancer therapy.
Clinical Cancer Research 11/2010; 16(22):5469-80. · 7.74 Impact Factor
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Manuela Aleku,
Petra Schulz,
Oliver Keil,
Ansgar Santel,
Ute Schaeper,
Britta Dieckhoff,
Oliver Janke,
Jens Endruschat,
Birgit Durieux,
Nadine Röder, [......],
Melanie Fechtner,
Kristin Möpert,
Gerald Fisch,
Sibylle Dames,
Wolfgang Arnold,
Karin Jochims,
Klaus Giese,
Bertram Wiedenmann,
Arne Scholz,
Jörg Kaufmann
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ABSTRACT: We have previously described a small interfering RNA (siRNA) delivery system (AtuPLEX) for RNA interference (RNAi) in the vasculature of mice. Here we report preclinical data for Atu027, a siRNA-lipoplex directed against protein kinase N3 (PKN3), currently under development for the treatment of advanced solid cancer. In vitro studies revealed that Atu027-mediated inhibition of PKN3 function in primary endothelial cells impaired tube formation on extracellular matrix and cell migration, but is not essential for proliferation. Systemic administration of Atu027 by repeated bolus injections or infusions in mice, rats, and nonhuman primates results in specific, RNAi-mediated silencing of PKN3 expression. We show the efficacy of Atu027 in orthotopic mouse models for prostate and pancreatic cancers with significant inhibition of tumor growth and lymph node metastasis formation. The tumor vasculature of Atu027-treated animals showed a specific reduction in lymph vessel density but no significant changes in microvascular density.
Cancer Research 01/2009; 68(23):9788-98. · 7.86 Impact Factor
