Fluorescence Probes of ALKBH2 Measure DNA Alkylation Repair and Drug Resistance Responses.
Angewandte Chemie (International ed. in English)
The DNA repair enzyme ALKBH2 is implicated in both tumorigenesis as well as resistance to chemotherapy in certain cancers. It is currently under study as a potential diagnostic marker and has been proposed as a therapeutic target. To date, however, there exist no direct methods for measuring the repair activity of ALKBH2 in vitro or in biological samples. Here we report a highly specific, fluorogenic probe design based on an oligonucleotide scaffold that reports directly on ALKBH2 activity both in vitro and in cell lysates. Importantly, the probe enables the monitoring of cellular regulation of ALKBH2 activity in response to treatment with the chemotherapy drug temozolomide through a simple fluorescence assay, which has only previously been observed through indirect means such as qPCR and Western blots. Furthermore, the probe provides a viable high throughput assay for drug discovery.
View details for PubMedID 30098084
Potent and Selective Inhibitors of 8-Oxoguanine DNA Glycosylase
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2018; 140 (6): 2105–14
The activity of DNA repair enzyme 8-oxoguanine DNA glycosylase (OGG1), which excises oxidized base 8-oxoguanine (8-OG) from DNA, is closely linked to mutagenesis, genotoxicity, cancer, and inflammation. To test the roles of OGG1-mediated repair in these pathways, we have undertaken the development of noncovalent small-molecule inhibitors of the enzyme. Screening of a PubChem-annotated library using a recently developed fluorogenic 8-OG excision assay resulted in multiple validated hit structures, including selected lead hit tetrahydroquinoline 1 (IC50 = 1.7 μM). Optimization of the tetrahydroquinoline scaffold over five regions of the structure ultimately yielded amidobiphenyl compound 41 (SU0268; IC50 = 0.059 μM). SU0268 was confirmed by surface plasmon resonance studies to bind the enzyme both in the absence and in the presence of DNA. The compound SU0268 was shown to be selective for inhibiting OGG1 over multiple repair enzymes, including other base excision repair enzymes, and displayed no toxicity in two human cell lines at 10 μM. Finally, experiments confirm the ability of SU0268 to inhibit OGG1 in HeLa cells, resulting in an increase in accumulation of 8-OG in DNA. The results suggest the compound SU0268 as a potentially useful tool in studies of the role of OGG1 in multiple disease-related pathways.
View details for PubMedID 29376367
Fluorescent Probes of DNA Repair.
ACS chemical biology
DNA repair is now understood to play a key role in a variety of disease states, most notably cancer. Tools for studying DNA have typically relied on traditional biochemical methods which are often laborious and indirect. Efforts to study the biology and therapeutic relevance of DNA repair pathways can be limited by such methods. Recently, specific fluorescent probes have been developed to aid in the study of DNA repair. Fluorescent probes offer the advantage of being able to directly assay for DNA repair activity in a simple, mix-and-measure format. This review will summarize the distinct classes of probe designs and their potential utility in varied research and preclinical settings.
View details for PubMedID 29156135
- Synthesis and Evaluation of Macrocyclic Peptide Aldehydes as Potent and Selective Inhibitors of the 20S Proteasome ACS MEDICINAL CHEMISTRY LETTERS 2016; 7 (3): 250-255