The Identification and Characterization of Lung Cancer Protein Biomarkers
using MALDI-TOF-MS
Michael C. Fitzgerald1, Michael Z. Wang1, Michael J. Camp2, Brandon Howard2,
and Edward F. Patz2
1Department of Chemistry, Duke University, Durham, NC 27708.
2Department of Radiology, Duke University Medical Center, Durham, NC 27708
Abstract:
MALDI-TOF mass spectrometry is an attractive method for generating protein
expression profiles of biological samples for proteomic research. Unique proteins
that are detected in the MALDI analysis of biological specimens from individuals
that are affected with disease can be of tremendous diagnostic and therapeutic
utility. Here we describe the results of our studies to identify protein biomarkers
of lung cancer. We have identified two unique protein ion signals in the MALDI-TOF
mass spectra of lung tumor cell lysates. Extensive purification of the proteins
giving rise to these ion signals, and subsequent peptide mapping and sequencing
experiments on the purified protein samples revealed that these protein biomarkers
were macrophage migration inhibitory factor and cyclophilin A. As part of
this work we also report on the use of a MALDI and H/D exchange-based approach
to facilitate the characterization and unambiguous identification of a protein
biomarker for lung cancer. This approach relies on the use of a new technique
termed SUPREX (Stability of Unpurified Proteins from Rates of H/D Exchange)
to detect protein specific ligand binding interactions in unpurified protein
fractions. Our work to identify these and other protein biomarkers in blood
with also be summarized.
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