0000000000633981
AUTHOR
Verena Fetz
Dynamic survivin in head and neck cancer: Molecular mechanism and therapeutic potential
Although disease management of head and neck squamous cell carcinomas (HNSCC) has improved significantly, therapy resistance leading to tumor recurrence still counteracts improvement of long-term survival. Consequently, identification of molecular markers that signal increased risk of treatment failure or, which can be exploited by targeted therapy, is urgently needed. Survivin is strongly expressed in HNSCC, and its proposed dual role as an apoptosis inhibitor and a mitotic effector positioned survivin in the front line of cancer research. Notably, survivin is detected as a cytoplasmic and as a nuclear protein in HNSCC patients, which stimulated numerous studies to investigate and to specu…
Translocation Biosensors – Cellular System Integrators to Dissect CRM1-Dependent Nuclear Export by Chemicogenomics
Fluorescent protein biosensors are powerful cellular systems biology tools for dissecting the complexity of cellular processes with high spatial and temporal resolution. As regulated nucleo-cytoplasmic transport is crucial for the modulation of numerous (patho)physiological cellular responses, a detailed understanding of its molecular mechanism would open up novel options for a rational manipulation of the cell. In contrast to genetic approaches, we here established and employed high-content cellular translocation biosensors applicable for dissecting nuclear export by chemicogenomics. A431 cell lines, stably expressing a translocation biosensor composed of glutathione S-transferase, GFP and…
Bioassays to monitor taspase1 function for the identification of pharmacogenetic inhibitors
Background Threonine Aspartase 1 (Taspase1) mediates cleavage of the mixed lineage leukemia (MLL) protein and leukemia provoking MLL-fusions. In contrast to other proteases, the understanding of Taspase1's (patho)biological relevance and function is limited, since neither small molecule inhibitors nor cell based functional assays for Taspase1 are currently available. Methodology/Findings Efficient cell-based assays to probe Taspase1 function in vivo are presented here. These are composed of glutathione S-transferase, autofluorescent protein variants, Taspase1 cleavage sites and rational combinations of nuclear import and export signals. The biosensors localize predominantly to the cytoplasm…
Inducible NO synthase confers chemoresistance in head and neck cancer by modulating survivin
The dual role of the inducible NO synthase (iNOS) and NO signaling in head and neck squamous cell carcinoma (HNSCC) is a complex and can both promote or inhibit tumor progression. However, the underlying molecular mechanisms are not yet resolved in detail. We show for the first time that conditions, favoring low NO levels conferred resistance against cisplatin/taxol-induced apoptosis in HNSCC cell lines. Cytoprotection was mediated by survivin, because we observed its upregulation subsequent to low doses of the NO donors S-nitroso-N-acetyl-penicillamine (SNAP) and sodium nitroprusside (SNP) or ectopic expression of physiologic amounts of iNOS. Also, RNAi-mediated depletion of survivin block…
Rapid formation of plasma protein corona critically affects nanoparticle pathophysiology
In biological fluids, proteins bind to the surface of nanoparticles to form a coating known as the protein corona, which can critically affect the interaction of the nanoparticles with living systems. As physiological systems are highly dynamic, it is important to obtain a time-resolved knowledge of protein-corona formation, development and biological relevancy. Here we show that label-free snapshot proteomics can be used to obtain quantitative time-resolved profiles of human plasma coronas formed on silica and polystyrene nanoparticles of various size and surface functionalization. Complex time- and nanoparticle-specific coronas, which comprise almost 300 different proteins, were found to …