. Author manuscript; available in PMC: 2015 Mar 28.

Published in final edited form as: Life Sci. 2014 Feb 2;100(1):25–34. doi: 10.1016/j.lfs.2014.01.072

Table I.

NTS ligands

Addition	IC₅₀, nM	% EGFR transactivation
NTS	4 ± 1	367 ± 31^**
NTS^8–13	10 ± 2	282 ± 24^**
Ac-NTS^8–13	7 ± 1	330 ± 28^**
NT^1–8	>2000	105 ± 7
SR48692	205 ± 31	95 ± 8
Gefitinib	>2000	98 ± 6
Levocabastine	>2000	102 ± 5

The ability of ligands to half-maximally (IC₅₀) inhibit specific ¹²⁵I-Tyr³-NTS binding to NCI-H1299 cells was determined at 37°C. The % EGFR tyrosine phosphorylation was determined 2 min after the addition of 100 nM of the indicated compound to NCI-H1299 cells. The mean value ± S.D. of 4 determinations is shown;

p < 0.01, ** by ANOVA.

The NTS structure is:

Pyr-Leu-Tyr-Glu-Asn-Lys-Pro-Arg-Arg-Pro-Tyr-Ile-Leu