Anchoring of FRET Sensors-A Requirement for Spatiotemporal Resolution.

FRET biosensors have become a routine tool for investigating mechanisms and components of cell signaling. Strategies for improving them for particular applications are continuously sought. One important aspect to consider when designing FRET probes is the dynamic distribution and propagation of signals within living cells.

TRAIL resistance in human neuroblastoma SK-N-AS cells is dependent on protein kinase C and involves inhibition of caspase-3 proteolytic processing.

Neuroblastoma is the most common solid extracranial cancer form in childhood with an etiology that is mostly unknown. Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been proposed as a promising future anticancer drug candidate, highly malignant neuroblastoma has been reported to acquire TRAIL resistance by mechanisms that are poorly understood. Here, we show by western blot analysis, and live cell imaging using anchored FRET sensors, that the resistance to TRAIL-induced apoptosis in human neuroblastoma SK-N-AS cells depends on an incomplete processing of procaspase-3, generating an immature and catalytically inactive 21 kDa fragment.

Sensitization to TRAIL-induced apoptosis in human neuroblastoma SK-N-AS cells by NF-κB inhibitors is dependent on reactive oxygen species (ROS).

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to induce apoptosis in a variety of cancer cell lines with almost no toxicity toward normal cells. However, many neuroblastoma cells acquire resistance to TRAIL by mechanisms that are poorly understood. The objective of this study was to investigate involvement of the transcription factor NF-κB in the resistance of human neuroblastoma SK-N-AS cells to TRAIL-induced apoptosis.

PI3-K- and PKC-dependent up-regulation of APP processing enzymes by retinoic acid.

Retinoic acid stimulates alpha-secretase processing of amyloid precursor protein (APP) and decreases beta-secretase cleavage that leads to amyloid-beta formation. Here, we investigated the effect of retinoic acid on the two putative alpha-secretases, the disintegrin metalloproteinases ADAM10 and TACE, and the beta-site cleaving enzyme BACE1, in human neuroblastoma SH-SY5Y cells. Western blot analysis showed that exposure to retinoic acid resulted in significantly increased levels of ADAM10 and TACE, suggesting that regulation of alpha-secretases causes the effects on APP processing.