Addiction to MTH1 protein results in intense expression in human breast cancer tissue as measured by liquid chromatography-isotope-dilution tandem mass spectrometry

Published

June 23, 2015

Author(s)

Erdem Coskun, Pawel Jaruga, Ann-Sofie Jemth, Olga Loseva, Leona D. Scanlan, Alessandro Tona, Mark S. Lowenthal, Thomas Helleday, M Miral Dizdar

Abstract

MTH1 protein sanitizes the nucleotide pool so that modified 2'-deoxynucleoside triphosphates (dNTPs) cannot be used in DNA replication. Cancer cells require MTH1 to avoid incorporation of modified dNTPs resulting in DNA damage mutations and cell death. Inhibition of MTH1 eradicates cancer, thus validating MTH1 as an anticancer target. Cancer cells may resist therapy that may damage dNTPs. MTH1 is overexpressed in many cancers. Accurate measurement of MTH1 in patient tissues may be essential for the use of MTH1 inhibitors in cancer therapy and for determining patient response. We present a novel approach involving liquid chromatography-tandem mass spectrometry with isotope-dilution to accurately measure human MTH1. We produced 15N-labeled full-length MTH1 to be used as an internal standard. Seven tryptic peptides of both MTH1 and 15N-MTH1 were identified following trypsin digestion. These peptides matched the theoretical peptides expected from trypsin digestion and provided a statistically significant protein score that would unequivocally identify MTH1. Product ion spectra of the tryptic peptides and their product ions were obtained. Selected-reaction monitoring was used to record the characteristic mass transitions of tryptic peptides to analyze mixtures of both proteins. Using the developed methodology, we positively identified and quantified hMTH1 in four human cell lines. The novel approach described herein is expected to be also applicable to the measurement of hMTH1 expression levels in cancerous vs. normal tissues in patients, thus helping develop treatment strategies and guide therapies.

Citation

Dna Repair

Volume

33

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.dnarep.2015.05.008

Keywords

Cancer biomarkers, DNA damage and repair, MTH1 protein, Mass spectrometry

Citation

Coskun, E. , Jaruga, P. , Jemth, A. , Loseva, O. , Scanlan, L. , Tona, A. , Lowenthal, M. , Helleday, T. and , M. (2015), Addiction to MTH1 protein results in intense expression in human breast cancer tissue as measured by liquid chromatography-isotope-dilution tandem mass spectrometry, Dna Repair, [online], https://doi.org/10.1016/j.dnarep.2015.05.008 (Accessed October 12, 2025)