Effects of Activating Mutations on EGFR Cellular Protein Turnover and Amino Acid Recycling Determined Using SILAC Mass Spectrometry

Table 1

Cell lines examined and EGFR turnover rate ().

Cell line	Mutation	Cell doubling time (hrs)	Compound	Inhibitor conc. (nM)	Turnover ( hrs)
A431	WT	31	N/A		28
H3255	L858R	42	N/A		10
H1975	L858R T790M	23	N/A		9.2
PC-9	Del 746–750	16	DMSO	0	7.5
PC-9	Del 746–750	N/A	Dacomitinib	18	5.8–9.1
PC-9	Del 746–750	N/A	Compound A	360	6.9–12

One wild-type and three mutant EGFR cell lines were analyzed. Cell lines with wild-type EGFR (A431), EGFR with a single activating mutant Del 746–750 (PC-9) or L858R (H3255), and the drug-resistant double mutant L858R/T790M (H1975) EGFR had turnover rate half-lives from 28 to 7.5 hours. These rates were not adjusted for amino acid recycling effects. The EGFR turnover rate half-lives in PC-9 cells dosed with inhibitors compound A and dacomitinib were reported as a range to include impact of cell viability on the measurement.