TITLE:
Activation of DNA Damage Signaling Components by Diagnostic Computed Tomography (CT) Scans Detected in Patient Samples Using an Electrochemiluminescence-Based Assay Platform
AUTHORS:
Yiching Hseih, Ulrike Begley, Lauren Endres, James Keith, Antonietta F. Hansen, Laurence Kaminsky, Brian McCandless, Thomas J. Begley
KEYWORDS:
DNA Damage Response, Ionizing Radiation, Diagnostic CT-Scan, Clinical Samples, ATM, CHK2, p53
JOURNAL NAME:
Advances in Bioscience and Biotechnology,
Vol.8 No.7,
July
27,
2017
ABSTRACT: Technologies
that measure activation of components of the DNA damage response (DDR) have
applications in exposure assessment and personalized medicine. The DDR and
associated DNA repair pathways encompass hundreds of proteins, making detailed
measurement of activation technically challenging and laborious. The purpose of
our study was to develop protein-specific assays for certain DDR components on a high-throughput
electrochemiluminescence (ECL)-based platform. We developed five working assay
pairs for ataxia telangiectasia mutated (ATM), checkpoint kinase 2 (CHK2), phosphorylated-ATM S1981, phosphorylated-CHK2 T68 and phosphorylated-tumor
protein p53 (p53) S15. We validated the ECL results against traditional immunoblot and γ-H2AX
foci measures in cell and cancer models. In an effort to test the ECL-based
technology in a clinical setting, we utilized peripheral blood mononuclear
cells (PBMCs) from patients undergoing computed tomography (CT) scans. CT scans represent both a valuable medical imaging
diagnostic and a controlled environmental exposure to ionizing radiation for
research studies, as they deliver ~2 to 31 millisieverts (mSv) and are known to
activate DDR components. In this study, we show that ECL-based technology can
measure the basal and damage-induced levels of DDR components in patient PBMC
samples. Using a blinded study design and patient matched pre- and post CT scan samples, we show that ECL-derived data can
consistently (94% of the time, 15/16 patients) identify PBMCs that have been
exposed to low dose ionizing radiation associated with CT scans. Ultimately, the results of our pilot clinical
study support the idea that ECL-based technology is applicable for use in
clinical and population cohorts that study components of the DDR.