Using Photoreactive Probes to Identify Viable Drug Targets in Non-small Cell Lung Cancer.

Recent advancements in chemoproteomics have accelerated new chemical tools for exploring protein ligandability in native biological systems. However, a large fraction of ligandable proteome in cancer cells remains poorly studied. Here, we present a practical and efficient sample processing method for liquid chromatography high-resolution-tandem mass spectrometry (HPLC-MS/MS) analysis. This method uses fully functionalized photoreactive fragment-like probes for profiling protein-ligand interactions in live cancer cells. This method adopts "on-bead" digestion in conjunction with ZipTip desalting prior sample injection to MS. By using this protocol, fragment protein interactions can be visualized using fluorescent imaging, and fragment-associated proteins can be identified via HPLC-MS/MS analysis. Approximately 16 samples would generally expect to be processed within 3 days by following this protocol.