Creation of different bioluminescence resonance energy transfer based biosensors with high affinity to VEGF

A Bioluminescence Resonance Energy Transfer-Based Reporter System: Characterization and Applications

Genome editing strategies and DNA repair research need powerful analytical tools. We generated a bioluminescence resonance energy transfer (BRET)-based reporter for the quantification of indel frequencies induced by DNA repair. The BRET reporter, expressed as a single molecule, consists of a mutated Renilla reniformis luciferase domain and a GFP2 domain separated by a shuttle-cloning box for the integration of any given endonuclease target sequence. The luciferase activity acts both as energy donor and as the internal standard, while the loss of GFP2 fluorescence acts as a reporter for the out-of-frame sequence alterations that result from the DNA repair via the non-homologous end joining/microhomology-mediated end joining DNA repair pathways of the endonuclease-mediated DNA double-strand break. This results in a decrease of the fluorescence/luminescence ratio. Employing this reporter in different experimental scenarios, using different cell lines and diseases targeted, we quantified the influence of both protein knockdown of DNA repair pathways as well as guide RNA mismatches on CRISPR-mediated nuclease activity and subsequent repair based on mutagenic repair on the reporter. In conclusion, we demonstrated this BRET-based reporter to be a robust and sensitive analytical tool for assessment of variety of different genome editing-based approaches.

Ways into Understanding HIF Inhibition

Simple Summary

Cancer cells adapt to hypoxia, survive, and grow. To that aim, they engage hypoxia-inducible pathways. These pathways are under intense investigation in search of new therapies to interfere with signaling components to kill cancer cells. Nowadays, new technologies enable more in-depth studies of hypoxia-induced signaling including protein–protein interaction and transcriptional processes, as well as the mode of action of different inhibitors. In this review, we give insight into useful techniques for studying the components of the hypoxia-inducible pathway and current inhibitors.

Abstract

Hypoxia is a key characteristic of tumor tissue. Cancer cells adapt to low oxygen by activating hypoxia-inducible factors (HIFs), ensuring their survival and continued growth despite this hostile environment. Therefore, the inhibition of HIFs and their target genes is a promising and emerging field of cancer research. Several drug candidates target protein–protein interactions or transcription mechanisms of the HIF pathway in order to interfere with activation of this pathway, which is deregulated in a wide range of solid and liquid cancers. Although some inhibitors are already in clinical trials, open questions remain with respect to their modes of action. New imaging technologies using luminescent and fluorescent methods or nanobodies to complement widely used approaches such as chromatin immunoprecipitation may help to answer some of these questions. In this review, we aim to summarize current inhibitor classes targeting the HIF pathway and to provide an overview of in vitro and in vivo techniques that could improve the understanding of inhibitor mechanisms. Unravelling the distinct principles regarding how inhibitors work is an indispensable step for efficient clinical applications and safety of anticancer compounds.

Coelenterazine-Dependent Luciferases as a Powerful Analytical Tool for Research and Biomedical Applications

: The functioning of bioluminescent systems in most of the known marine organisms is based on the oxidation reaction of the same substrate-coelenterazine (CTZ), catalyzed by luciferase. Despite the diversity in structures and the functioning mechanisms, these enzymes can be united into a common group called CTZ-dependent luciferases. Among these, there are two sharply different types of the system organization-Ca2+-regulated photoproteins and luciferases themselves that function in accordance with the classical enzyme-substrate kinetics. Along with deep and comprehensive fundamental research on these systems, approaches and methods of their practical use as highly sensitive reporters in analytics have been developed. The research aiming at the creation of artificial luciferases and synthetic CTZ analogues with new unique properties has led to the development of new experimental analytical methods based on them. The commercial availability of many ready-to-use assay systems based on CTZ-dependent luciferases is also important when choosing them by first-time-users. The development of analytical methods based on these bioluminescent systems is currently booming. The bioluminescent systems under consideration were successfully applied in various biological research areas, which confirms them to be a powerful analytical tool. In this review, we consider the main directions, results, and achievements in research involving these luciferases.