CRT0044876

Catalog No.S7449 Batch:S744901

Technical Data

Formula	C₉H₆N₂O₄
Molecular Weight	206.15	CAS No.	6960-45-8
Solubility (25°C)*	In vitro	DMSO	41 mg/mL (198.88 mM)
		Ethanol	1 mg/mL (4.85 mM)
		Water	Insoluble
* <1 mg/ml means slightly soluble or insoluble. * Please note that Selleck tests the solubility of all compounds in-house, and the actual solubility may differ slightly from published values. This is normal and is due to slight batch-to-batch variations. * Room temperature shipping (Stability testing shows this product can be shipped without any cooling measures.)

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Biological Activity

Description

CRT0044876 (NSC 69877, 7-NO2-ICA) is a potent and selective APE1 inhibitor with IC50 of ~3 μM.

Targets

APE1 ^[1]

~3 μM

In vitro

CRT0044876 potently inhibits the AP endonuclease, 3'-phosphodiesterase and 3'-phosphatase activities of APE1, and exhibits the selectivity for the inhibition of exonuclease III family. CRT0044876 potentiates the cytotoxicity of several DNA base-targeting compounds with an accumulation of unrepaired AP sites. ^[1] CRT0044876, by inhibition of the BER pathway increases oxidative DNA damage temporally related to increased intracellular reactive oxygen species in an acidic tumor microenvironment, and thus results in cell cycle arrests and increased DNA double strand breaks, leading to cell death. ^[2]

Protocol (from reference)

Kinase Assay:^{^[1]}	AP site cleavage assay BER reaction buffer comprises 40 mM HEPES–KOH (pH 7.8), 5 mM MgCl₂, 0.5 mM DTT and 0.1 mM EDTA. A 10 μl AP site cleavage reaction comprised of BER buffer mix, purified protein (3.3 nM final concentration of APE1) and 0.75 ng reduced AP site double-stranded oligonucleotide. The mixture is incubated at 37°C for 1 h. A total of 1 μl of stop buffer (50% glycerol, 10 mM Tris–HCl, 1 mM EDTA, 0.1% bromophenol blue and 0.1% Xylene cyanol) is added, and the sample mixture is denatured at 90–100°C for 2 min. The sample is then run on a 15% TBE Criterion™ Pre-Cast Gel, with electrophoresis at a constant current of 30 mA for 30 min, and the radiolabeled substrate and reaction products are visualized using a phosphorImager. The inhibitory activity of potential APE1-targeting compounds are analyzed at drug concentrations ranging from 0.1 to 100 μM. The resolved radiolabeled bands are quantified using ImageQuant software analysis, and IC50 values are calculated by determining the concentration of the inhibitor that reduced APE1 activity to 50% of the control values.
Cell Assay:^{^[1]}	Cell lines HT1080 fibrosarcoma cells Concentrations 100-500 μM Incubation Time 7-10 days Method HT1080 fibrosarcoma cells are grown in 2% RPMI medium [supplemented with penicillin 0.06 g/l, streptomycin 0.1 g/l (pH 7.0), 10% fetal bovine serum and 4 mM glutamine]. Only cells with a plating efficiency of ≥60% are used for clonogenic survival analysis. Tissue culture dishes (10 cm) are seeded with 500 cells per dish and the culture is maintained in a humidified incubator at 37°C in an atmosphere of 5% CO₂ and 95% air. To evaluate the toxicity profile of putative APE1 inhibitors, various concentrations (100–500 μM) of inhibitor are added to the medium, and cultures were incubated for 7-10 days until cell colonies are formed. Colonies are fixed [75% (v/v) methanol, 25% (v/v) acetic acid] for 30 min and stained with crystal violet (1 mg/ml in distilled water) for 4 h at room temperature. Visible colonies are counted on a colony counter.

Kinase Assay:^{^[1]}

AP site cleavage assay
BER reaction buffer comprises 40 mM HEPES–KOH (pH 7.8), 5 mM MgCl₂, 0.5 mM DTT and 0.1 mM EDTA. A 10 μl AP site cleavage reaction comprised of BER buffer mix, purified protein (3.3 nM final concentration of APE1) and 0.75 ng reduced AP site double-stranded oligonucleotide. The mixture is incubated at 37°C for 1 h. A total of 1 μl of stop buffer (50% glycerol, 10 mM Tris–HCl, 1 mM EDTA, 0.1% bromophenol blue and 0.1% Xylene cyanol) is added, and the sample mixture is denatured at 90–100°C for 2 min. The sample is then run on a 15% TBE Criterion™ Pre-Cast Gel, with electrophoresis at a constant current of 30 mA for 30 min, and the radiolabeled substrate and reaction products are visualized using a phosphorImager. The inhibitory activity of potential APE1-targeting compounds are analyzed at drug concentrations ranging from 0.1 to 100 μM. The resolved radiolabeled bands are quantified using ImageQuant software analysis, and IC50 values are calculated by determining the concentration of the inhibitor that reduced APE1 activity to 50% of the control values.

Cell Assay:^{^[1]}

Cell lines
HT1080 fibrosarcoma cells
Concentrations
100-500 μM
Incubation Time
7-10 days
Method
HT1080 fibrosarcoma cells are grown in 2% RPMI medium [supplemented with penicillin 0.06 g/l, streptomycin 0.1 g/l (pH 7.0), 10% fetal bovine serum and 4 mM glutamine]. Only cells with a plating efficiency of ≥60% are used for clonogenic survival analysis. Tissue culture dishes (10 cm) are seeded with 500 cells per dish and the culture is maintained in a humidified incubator at 37°C in an atmosphere of 5% CO₂ and 95% air. To evaluate the toxicity profile of putative APE1 inhibitors, various concentrations (100–500 μM) of inhibitor are added to the medium, and cultures were incubated for 7-10 days until cell colonies are formed. Colonies are fixed [75% (v/v) methanol, 25% (v/v) acetic acid] for 30 min and stained with crystal violet (1 mg/ml in distilled water) for 4 h at room temperature. Visible colonies are counted on a colony counter.

References

Selleck's CRT0044876 has been cited by 2 publications

Base-excision repair pathway regulates transcription-replication conflicts in pancreatic ductal adenocarcinoma [ Cell Rep, 2024, 43(10):114820]	PubMed: 39368091
Synergistic drug combinations for cancer identified in a CRISPR screen for pairwise genetic interactions. [ Nat Biotechnol, 2017, 35(5):463-474]	PubMed: 28319085

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SHIPPING AND STORAGE
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