Related Experiment Videos
Potent inhibition of human telomerase by nitrostyrene derivatives
Joo Hee Kim1, Jun Hyun Kim, Gun Eui Lee
1DNA Link, Milk Building, Yonsei University, Seoul, Korea.
Abstract:
Telomerase activity is expressed in most types of cancer cells but not in normal somatic cells, suggesting that telomerase may be an important target for cancer chemotherapy. Inhibition of telomerase results in telomere erosion, leading to the subsequent growth arrest of cancer cells followed by senescence or cell death. In this study, we screened a chemical library for the inhibition of human telomerase, identifying three inhibitors. All compounds contained a common nitrostyrene moiety conjugated to different side chains. One of these compounds, 3-(3,5-dichlorophenoxy)-nitrostyrene (DPNS), showed the most potent inhibitory effect, with 50% inhibition at approximately 0.4 microM and did not inhibit DNA and RNA polymerases, including retroviral reverse transcriptase. A series of enzyme kinetic experiments suggests that DPNS is a mixed-type noncompetitive inhibitor, with an inhibitor-binding site distinct from the binding sites for the telomeric substrate primer and the deoxynucleoside-5'-triphosphates. Extensive propagation of cancer cell line in the presence of DPNS resulted in progressive telomere erosion followed by the induction of senescence phenotype. The results presented here demonstrate that DPNS is a highly selective, small-molecule telomerase inhibitor in vitro and could be useful as a lead molecule for the further development of inhibitors with an improved potential for efficacy in vivo.
Insights
Researchers identified a potent telomerase inhibitor, 3-(3,5-dichlorophenoxy)-nitrostyrene (DPNS), from a chemical library screen. DPNS selectively inhibits human telomerase, leading to cancer cell senescence and death, suggesting its potential for cancer chemotherapy.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- Telomerase is active in most cancer cells but not normal cells, making it a potential cancer chemotherapy target.
- Inhibiting telomerase causes telomere shortening, leading to cancer cell growth arrest, senescence, or death.
Purpose of the Study:
- To screen a chemical library for inhibitors of human telomerase.
- To identify and characterize novel, selective telomerase inhibitors for potential cancer therapy.
Main Methods:
- Chemical library screening for telomerase inhibition.
- Enzyme kinetic studies to determine inhibition type and mechanism.
- Cell-based assays to assess telomere length and senescence induction.
Main Results:
- Identified three nitrostyrene-containing compounds that inhibit human telomerase.
- 3-(3,5-dichlorophenoxy)-nitrostyrene (DPNS) demonstrated potent inhibition (IC50 ≈ 0.4 μM) without affecting other polymerases.
- DPNS acts as a mixed-type noncompetitive inhibitor, binding to a site distinct from substrate and nucleotide binding sites.
- DPNS treatment led to progressive telomere erosion and induced senescence in cancer cell lines.
Conclusions:
- DPNS is a highly selective, small-molecule inhibitor of human telomerase in vitro.
- DPNS exhibits a unique noncompetitive inhibition mechanism.
- DPNS shows promise as a lead compound for developing novel cancer therapeutics targeting telomerase.