The tyrosine kinase inhibitor Gefitinib reduces C. elegans stress-induced sleep, but not likely via LET-23/EGFR inhibition

Abstract

The anticancer drug Gefitinib is a tyrosine kinase inhibitor with selectivity for the Epidermal Growth Factor Receptor (EGFR/ErbB1). As the C. elegans EGF receptor LET-23 shares notable structural homology over its kinase domain with human EGFR, we wished to examine whether Gefitinib treatment can interfere with LET-23-dependent processes. We show that Gefitinib disrupts C. elegans stress-induced sleep (SIS) but does not impact EGF overexpression-induced sleep nor vulva induction. These findings indicate that Gefitinib does not interfere with LET-23 signaling and impairs SIS through an off-target mechanism.

Figure 1. Gefitinib-treated animals show reduced SIS, but not other signs of LET-23/EGFR inhibition

Wild type N2 animals were exposed from hatching to either 10 uM Gefitinib or an equivalent concentration of DMF vehicle and examined for defects in EGFR-dependent processes. (A–C) Young adult animals were assayed for stress-induced sleep (SIS) as described in methods. Gefitinib-treated animals show reduced quiescence relative to vehicle controls during (A) heat-induced sleep, (B) UV-induced sleep, and (C) Cry5B toxin-induced sleep. (D) Young adult animals were assayed for the sleep-like state triggered by ubiquitous overexpression (OE) of the EGF family ligand LIN-3. Gefitinib-treated animals show no defect in LIN-3(OE)-induced sleep. (E) Vulval induction was examined in Gefitinib and vehicle-treated animals at the L4 stage. All animals showed vulval patterning indicative of three VPCs having adopted a vulval fate. At least three trials of 25 animals were performed in A-D. In C and E, the number of animals examined is shown at the base of each bar. P values were determined by unpaired t tests, AUC = area under the curve.