Label-free detection of telomerase activity using guanine electrochemical oxidation signal
Makaleler > Tam Makale · 2007
Yazarlar: Ugur ESKIOCAK, Dilşat ARIKSOYSAL, Mehmet OZSOZ, Huseyin Avni OKTEM
ANALYTICAL CHEMISTRY, SCI Expanded İndekslerine Giren Dergi, Uluslararası, 2007, cilt 79, ss 8807-8811
DOI: 10.1021/ac071014r
Özet
Telomerase is an important biomarker for cancer cells and its activation in 85% of all cancer types confers a clinical diagnostic value. A label-free electrochemical assay based on guanine oxidation signal to measure telomerase activity is described. This developed technology combined with a disposable sensor, carbon graphite electrode (CGE), and differential pulse voltammetry (DPV) was performed by using PCR amplicons with/without telomeric repeats as the guanine oxidation signal observed at +1.0 V measured after the immobilization of PCR products. Guanine oxidation signal was chosen as a measure of telomerase activity because a substantial increase in the number of guanines was introduced by the action of telomerase which adds hexameric repeats (TTAGGG)(n) that contain 50% guanine. The developed assay was shown to specifically measure telomerase activity from cell extracts, and elongation rates increased linearly in a concentration dependent manner. Telomerase activity could be detected in cell extracts containing as low as 100 ng/mu L of protein. All of the electrochemical measurements were also confirmed with the conventional TRAP-silver staining assay. Rapidity, simplicity, and the label-free nature of the developed assay make it suitable for practical use in quantitative determination of telomerase activity from clinical samples for diagnosis of cancer.