SLAS Discovery - Special Issue on Advances in MALDI Mass Spectrometry for Drug Discovery - Volume 22 Issue 10 - December 2017 - 1203

727701
research-article2017

JBXXXX10.1177/2472555217727701SLAS DISCOVERY: Advancing Life Sciences R&DBeeman et al.

Original Research

Integration of an In Situ MALDI-Based
High-Throughput Screening Process:
A Case Study with Receptor Tyrosine
Kinase c-MET

SLAS Discovery
2017, Vol. 22(10) 1203-1210
© 2017 Society for Laboratory
Automation and Screening
https://doi.org/10.1177/2472555217727701
DOI: 10.1177/2472555217727701
journals.sagepub.com/home/jbx

Katrin Beeman1, Jens Baumgärtner2, Manuel Laubenheimer1,
Karlheinz Hergesell1, Martin Hoffmann1, Ulrich Pehl1, Frank Fischer2,
and Jan-Carsten Pieck1

Abstract
Mass spectrometry (MS) is known for its label-free detection of substrates and products from a variety of enzyme reactions.
Recent hardware improvements have increased interest in the use of matrix-assisted laser desorption/ionization time-offlight (MALDI-TOF) MS for high-throughput drug discovery. Despite interest in this technology, several challenges remain
and must be overcome before MALDI-MS can be integrated as an automated "in-line reader" for high-throughput drug
discovery. Two such hurdles include in situ sample processing and deposition, as well as integration of MALDI-MS for
enzymatic screening assays that usually contain high levels of MS-incompatible components. Here we adapt our c-MET
kinase assay to optimize for MALDI-MS compatibility and test its feasibility for compound screening. The pros and cons
of the Echo (Labcyte) as a transfer system for in situ MALDI-MS sample preparation are discussed. We demonstrate that
this method generates robust data in a 1536-grid format. We use the MALDI-MS to directly measure the ratio of c-MET
substrate and phosphorylated product to acquire IC50 curves and demonstrate that the pharmacology is unaffected. The
resulting IC50 values correlate well between the common label-based capillary electrophoresis and the label-free MALDIMS detection method. We predict that label-free MALDI-MS-based high-throughput screening will become increasingly
important and more widely used for drug discovery.
Keywords
MALDI-MS, mass spectrometry, high-throughput screening, HTS, acoustic transfer

Introduction
Mass spectrometry (MS) is a well-established tool for
many areas of drug discovery.19 Recently, the desire to
also apply MS techniques to high-throughput screening
(HTS) for hit discovery has strongly increased. So far,
limitations concerning sample preparation, as well as
measurement and analysis speeds, prevented the use of
MS for HTS approaches. However, new advancements
have made matrix-assisted laser desorption/ionization
(MALDI) MS technology an ideal candidate for hit identification with the promise to open up new possibilities in
high-throughput drug discovery.1,2,5
Until recently, the pharmaceutical and research screening community considered fluorescent-and chemiluminescent-based bioanalytical detection methods the preferred
assay platform for isolated enzyme assays. Those assays are
sensitive and fast, with a high degree of reproducibility and
repeatability, and they are universal methods to evaluate a
variety of targets. However, one of the biggest challenges

is false-positive or false-negative readouts. Those false
readouts are a common concern and are usually caused by
1

Global Research & Development, Discovery Technologies, Discovery
Pharmacology, Merck KGaA, Darmstadt, Germany
2
Analytics Healthcare, Biomolecule Analytics, Merck KGaA, Darmstadt,
Germany
Received April 28, 2017, and in revised form Aug 2, 2017. Accepted for
publication Aug 2, 2017.
Supplementary material is available online with this article.
Corresponding Authors:
Jan Carsten Pieck, Global Research & Development, Discovery
Technologies, Discovery Pharmacology, Merck KGaA, Frankfurter
Straße 250, Darmstadt, 64293, Germany.
Email: carsten.pieck@merckgroup.com
Katrin Beeman, Global Research & Development, Discovery
Technologies, Discovery Pharmacology, Merck KGaA, Frankfurter
Straße 250, Darmstadt, 64293, Germany.
Email: katrin.beeman@merckgroup.com

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