Citation Details

Journal Article

in vivo imaging; MMPSense; microRNA 21; glioma

Substantial data indicate that microRNA 21 (miR-21) is significantly elevated in glioblastoma (GBM) and in many other tumors of various origins. This microRNA has been implicated in various aspects of carcinogenesis, including cellular proliferation, apoptosis, and migration. We demonstrate that miR-21 regulates multiple genes associated with glioma cell apoptosis, migration, and invasiveness, including the RECK and TIMP3 genes, which are suppressors of malignancy and inhibitors of matrix metalloproteinases (MMPs). Specific inhibition of miR-21 with antisense oligonucleotides leads to elevated levels of RECK and TIMP3 and therefore reduces MMP activities in vitro and in a human model of gliomas in nude mice. Moreover, downregulation of miR-21 in glioma cells leads to decreases of their migratory and invasion abilities. Our data suggest that miR-21 contributes to glioma malignancy by downregulation of MMP inhibitors, which leads to activation of MMPs, thus promoting invasiveness of cancer cells. Our results also indicate that inhibition of a single oncomir, like miR-21, with specific antisense molecules can provide a novel therapeutic approach for “physiological” modulation of multiple proteins whose expression is deregulated in cancer.

Journal Article

4T1-luc2, 4T1, Bioware, IVIS

Sunitinib is a potent and clinically approved tyrosine kinase inhibitor that can suppress tumour growth by inhibiting angiogenesis. However, conflicting data exist regarding the effects of this drug on the growth of metastases in preclinical models. Here we use 4T1 and RENCA tumour cells, which both form lung metastases in Balb/c mice, to re-address the effects of sunitinib on the progression of metastatic disease in mice. We show that treatment of mice with sunitinib prior to intravenous injection of tumour cells can promote the seeding and growth of 4T1 lung metastases, but not RENCA lung metastases, showing that this effect is cell line dependent. However, increased metastasis occurred only upon administration of a very high sunitinib dose, but not when lower, clinically relevant doses were used. Mechanistically, high dose sunitinib led to a pericyte depletion effect in the lung vasculature that correlated with increased seeding of metastasis. By administering sunitinib to mice after intravenous injection of tumour cells, we demonstrate that while sunitinib does not inhibit the growth of 4T1 lung tumour nodules, it does block the growth of RENCA lung tumour nodules. This contrasting response was correlated with increased myeloid cell recruitment and persistent vascularisation in 4T1 tumours, whereas RENCA tumours recruited less myeloid cells and were more profoundly devascularised upon sunitinib treatment. Finally, we show that progression of 4T1 tumours in sunitinib treated mice results in increased hypoxia and increased glucose metabolism in these tumours and that this is associated with a poor outcome. Taken together, these data suggest that the effects of sunitinib on tumour progression are dose-dependent and tumour model-dependent. These findings have relevance for understanding how anti-angiogenic agents may influence disease progression when used in the adjuvant or metastatic setting in cancer patients.

Journal Article

IVIS, RediJect Inflammation Probe, chemiluminescence, XenoLight, Adaptor Proteins, Signal Transducing/metabolism; Animals; Cell Differentiation; Concanavalin A/toxicity; Dengue Hemorrhagic Fever/etiology; Disease Models, Animal; Disease Progression; Female; Humans; Immunity, Innate; Intracellular Signaling Peptides and Proteins/metabolism; Lectins, C-Type/deficiency/genetics/*immunology; Liver/metabolism/pathology; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Immunological; Myeloid Cells/*immunology/pathology; Nitric Oxide/biosynthesis; Nitric Oxide Synthase Type II/metabolism; Nitric Oxide Synthase Type III/metabolism; Phosphatidylinositol 3-Kinases/metabolism; Protein-Tyrosine Kinases/metabolism; Proto-Oncogene Proteins c-akt/metabolism; Receptors, Cell Surface/deficiency/genetics/*immunology; Receptors, Immunologic/metabolism; Shock/*etiology/*immunology/metabolism/pathology; Signal Transduction; Systemic Inflammatory Response; Syndrome/etiology/immunology/metabolism/pathology; Tumor Necrosis Factor-alpha/biosynthesis

Systemic inflammatory response syndrome (SIRS) is a potentially lethal condition, as it can progress to shock, multi-organ failure, and death. It can be triggered by infection, tissue damage, or hemorrhage. The role of tissue injury in the progression from SIRS to shock is incompletely understood. Here, we show that treatment of mice with concanavalin A (ConA) to induce liver injury triggered a G-CSF-dependent hepatic infiltration of CD11b+Gr-1+Ly6G+Ly6C+ immature myeloid cells that expressed the orphan receptor myeloid DAP12-associated lectin-1 (MDL-1; also known as CLEC5A). Activation of MDL-1 using dengue virus or an agonist MDL-1-specific antibody in the ConA-treated mice resulted in shock. The MDL-1+ cells were pathogenic, and in vivo depletion of MDL-1+ cells provided protection. Triggering MDL-1 on these cells induced production of NO and TNF-alpha, which were found to be elevated in the serum of treated mice and required for MDL-1-induced shock. Surprisingly, MDL-1-induced NO and TNF-alpha production required eNOS but not iNOS. Activation of DAP12, DAP10, Syk, PI3K, and Akt was critical for MDL-1-induced shock. In addition, Akt physically interacted with and activated eNOS. Therefore, triggering of MDL-1 on immature myeloid cells and production of NO and TNF-alpha may play a critical role in the pathogenesis of shock. Targeting the MDL-1/Syk/PI3K/Akt/eNOS pathway represents a potential new therapeutic strategy to prevent the progression of SIRS to shock.

Journal Article

IVIS, B16-F10-luc-G5, B16F10-luc-G5, B16-F10-luc, B16F10-luc, Animals; COS Cells; Catechin/analogs & derivatives/chemistry/pharmacology; Cell Line; Cercopithecus aethiops; Ephrins/*metabolism; Mice; Polyphenols/*chemistry/*pharmacology; Protein Binding/drug effects; Protein Interaction Maps/*drug effects; Receptor, EphA4/antagonists & inhibitors/metabolism; Receptors, Eph Family/antagonists & inhibitors/*metabolism; Signal Transduction/drug effects; Small Molecule Libraries/chemistry/pharmacology; Tea/*chemistry

Tea contains a variety of bioactive chemicals, such as catechins and other polyphenols. These compounds are thought to be responsible for the health benefits of tea consumption by affecting the function of many cellular targets, not all of which have been identified. In a high-throughput screen for small molecule antagonists of the EphA4 receptor tyrosine kinase, we identified five tea polyphenols that substantially inhibit EphA4 binding to a synthetic peptide ligand. Further characterization of theaflavin monogallates from black tea and epigallocatechin-3,5-digallate from green tea revealed that these compounds at low micromolar concentrations also inhibit binding of the natural ephrin ligands to EphA4 and several other Eph receptors in in vitro assays. The compounds behave as competitive EphA4 antagonists, and their inhibitory activity is affected by amino acid mutations within the ephrin binding pocket of EphA4. In contrast, the major green tea catechin, epigallocatechin-3-gallate (EGCG), does not appear to be an effective Eph receptor antagonist. In cell culture assays, theaflavin monogallates and epigallocatechin-3,5-digallate inhibit ephrin-induced tyrosine phosphorylation (activation) of Eph receptors and endothelial capillary-like tube formation. However, the wider spectrum of Eph receptors affected by the tea derivatives in cells suggests additional mechanisms of inhibition besides interfering with ephrin binding. These results show that tea polyphenols derived from both black and green tea can suppress the biological activities of Eph receptors. Thus, the Eph receptor tyrosine kinase family represents an important class of targets for tea-derived phytochemicals.

Journal Article

Xen5, Xen39, Xen26, Xen14, Xen36, Xen 5, Xen 39, Xen 26, Xen 14, Xen 36, Psuedomonas aeruginosa, S. aureus, Klebsiella, E. coli, Salmonella,

The 3(2H) furanone derivative 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) was investigated for its antimicrobial and cell-adhesion inhibition properties against Klebsiella pneumoniae Xen 39, Staphylococcus aureus Xen 36, Escherichia coli Xen 14, Pseudomonas aeruginosa Xen 5 and Salmonella typhimurium Xen 26. Nanofibers electrospun from solution blends of DMHF and poly(vinyl alcohol) (PVA) were tested for their ability to inhibit surface-attachment of bacteria. Antimicrobial and adhesion inhibition activity was determined via the plate counting technique. To quantify viable but non-culturable cells and to validate the plate counting results, bioluminescence and fluorescence studies were carried out. Nanofiber production was upscaled using the bubble electrospinning technique. To ascertain that no DMHF leached into filtered water, samples of water filtered through the nanofibrous mats were analyzed using gas chromatography coupled with mass spectrometry (GC-MS). Scanning electron microscopy (SEM) and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) were used to characterize the electrospun nanofibers.