Tandem photoaffinity labeling–bioorthogonal conjugation in medicinal chemistry

Lapinsky, David J.

doi:10.1016/j.bmc.2012.09.010

Cited by 101 publications

(83 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…119,120 In particular, photoaffinity labeling, via bio-orthogonal click chemistry reactions, negates the requirement for expensive and difficult-to-use radiolabeled probes. 121 Once targets are labeled, a combination of affinity enrichment and quantitative proteomics (e.g., stable isotope labeling by amino acids in cell culture, 122 For instances in which chemical modification into a suitable affinity probe is not readily available, drug affinity responsive target stability (DARTS) has been developed as a label-free method that takes advantage of a reduction in protease susceptibility of the target protein(s) upon ligand binding. 123 As these and other target identification methodologies improve, they could also be incorporated into ongoing drug discovery programs to gain a clearer understanding around the molecular targets of tool, candidate, and clinical compounds.…”

Section: Cell-based Hts and Target Deconvolutionmentioning

confidence: 99%

Addressing the Right Targets in Oncology: Challenges and Alternative Approaches

Stock¹,

Jones²,

Hammonds³

et al. 2015

SLAS Discovery

View full text Add to dashboard Cite

Translating existing and emerging knowledge of cancer biology into effective novel therapies remains a great challenge in drug discovery. A firm understanding of the target biology, confidence in the supporting preclinical research, and access to diverse chemical matter is required to lower attrition rates and prosecute targets effectively. Understanding past successes and failures will aid in refining this process to deliver further therapeutic benefit to patients. In this review, we suggest that early oncology drug discovery should focus on selection and prosecution of cancer targets with strong disease biology rather than on more chemically "druggable" targets with only modest disease-linkage. This approach offers higher potential benefit but also increases the need for innovative and alternative approaches. These include using different methods to validate novel targets and identify chemical matter, as well as raising the standards and our interpretation of the scientific literature. The combination of skills required for this emphasizes the need for broader early collaborations between academia and industry.

show abstract

Section: Cell-based Hts and Target Deconvolutionmentioning

confidence: 99%

Addressing the Right Targets in Oncology: Challenges and Alternative Approaches

Stock¹,

Jones²,

Hammonds³

et al. 2015

SLAS Discovery

View full text Add to dashboard Cite

show abstract

“…To buck-up the missing tag, post-labeling approaches were developed by application of click chemistry. [60][61][62][63] A diol-type diazirine 48 was utilized to introduce an aldehyde by periodate oxidation followed by selective coupling with biotinyl hydrazide to detect trace amounts of labeled product. 64) Preinstalled alkylazide tag on 49 was substantially stable to the photolytic 65) The postlabeling approaches require, however, large excess reagents to complete enough tag on the labeled proteins existing very low concentrations.…”

Section: Follow-up Tagging After Photoaffinity Labelingmentioning

confidence: 99%

Development and Leading-Edge Application of Innovative Photoaffinity Labeling

Hatanaka

2015

Chem. Pharm. Bull.

View full text Add to dashboard Cite

“…For example, compounds 19b and 19c were poorly soluble at assay concentrations (cLogP: 19a, 5.8; 19b, 6.0; 19c, 6.1; 1, 5.2) and did not return meaningful dose−response curves. A significantly more soluble CNH compound (22) (cLogP: 3.9−4.0) was elaborated from the S-methylation of (2,6-dimethylphenyl)thiourea, 14 20, to give 21, followed by displacement with hydrazine and condensation with 4-bromobenzaldehyde to give the hydrazinecarboximidamide, 22. Unfortunately, the bioactivity of this compound was diminished (IC 50 = 13.8 μM).…”

mentioning

confidence: 99%

“…22 Given the low activity of 17 and the limited potential for making modifications in the N 4 -phenyl ring, it is not apparent how such a "clickable" linker could be included into a bioactive photoaffinity version of 1. Nevertheless, the convenience of this approach led us to synthesize compound 28, an N 2 -propargyl analogue of 4 ( Table 2).…”

mentioning

confidence: 99%

Structure–Activity Relationship of Semicarbazone EGA Furnishes Photoaffinity Inhibitors of Anthrax Toxin Cellular Entry

Jung

Chamberlain

et al. 2014

ACS Med. Chem. Lett.

View full text Add to dashboard Cite

EGA, 1, prevents the entry of multiple viruses and bacterial toxins into mammalian cells by inhibiting vesicular trafficking. The cellular target of 1 is unknown, and a structure− activity relationship study was conducted in order to develop a strategy for target identification. A compound with midnanomolar potency was identified (2), and three photoaffinity labels were synthesized (3−5). For this series, the expected photochemistry of the phenyl azide moiety is a more important factor than the IC 50 of the photoprobe in obtaining a successful photolabeling event. While 3 was the most effective reversible inhibitor of the series, it provided no protection to cells against anthrax lethal toxin (LT) following UV irradiation. Conversely, 5, which possessed weak bioactivity in the standard assay, conferred robust irreversible protection vs LT to cells upon UV photolysis. KEYWORDS: Photoaffinity labeling, semicarbazone, aryl azide, anthrax lethal toxin, endosomal trafficking A common mechanism by which viruses and bacterial toxins enter host cells involves trafficking from an early to a late endosome followed by release into the cytoplasm as triggered by endosomal acidification. 1−3 Inhibition of this process represents a host-targeted strategy for the development of broad-spectrum antiviral and antibacterial drugs. Recently, EGA, N 1 -(4-bromobenzylidene)-N 4 -(2,6-dimethylphenyl)-semicarbazone, 1, was identified from a high-throughput phenotypic screen to protect cells from anthrax lethal toxin (LT). 4 Further investigations showed that 1 protected cells from multiple viruses and bacterial toxins that rely on pHdependent endosomal trafficking to enter cells. Although the details of the biochemical mechanism have been studied, the cellular target(s) remain unknown. We have conducted a structure−activity relationship (SAR) study with the goal of improving the potency of 1 and developing a strategy for photoaffinity labeling and identification of the involved proteins.A series of derivatives of 1 were synthesized and tested, revealing precise requirements for activity in a tight and relatively flat structure−activity landscape. The 2,6-dimethyl substitution in the N 4 -ring as well as an unaltered semicarbazone core were shown to be optimal for activity while certain modifications to the N 1 -phenyl ring were tolerated. From the SAR, a compound more potent than the original hit was generated, namely the N 1 -2-fluoro-4-bromophenyl analogue (IC 50 = 0.4 μM), 2. In addition, three photoaffinity probes, 3−5, two of which possess low micromolar activity, were designed and synthesized. Our key finding is that the expected photochemistry of the phenyl azide moiety is a more important factor than the IC 50 of the photoprobe in achieving successful photolabeling. While 3 was the most potent inhibitor of intoxication by LT in the standard assay, it did not provide protection to the cells upon UV photolysis. Conversely 5, which possesses two fluorine atoms ortho to the azido function, was a poor inhibitor in the stand...

show abstract

Tandem photoaffinity labeling–bioorthogonal conjugation in medicinal chemistry

Cited by 101 publications

References 76 publications

Addressing the Right Targets in Oncology: Challenges and Alternative Approaches

Addressing the Right Targets in Oncology: Challenges and Alternative Approaches

Development and Leading-Edge Application of Innovative Photoaffinity Labeling

Structure–Activity Relationship of Semicarbazone EGA Furnishes Photoaffinity Inhibitors of Anthrax Toxin Cellular Entry

Contact Info

Product

Resources

About