Abstract 1306: SR48692 inhibits EGF receptor transactivation and proliferation of lung cancer cells.

Abstract

Abstract Neurotensin (NTS) is an autocrine growth factor for some lung cancer cells (Moody et al., 1985;Life Sci 36:1727). NTS binds with high affinity to the GPCR NTSR1 causing phosphatidyl inositol turnover and proliferation of lung cancer cells; SR48692 is a NTSR1 antagonist (Moody et al., 2001; Peptides 22:109). NTSR1 expression is associated with poor survival of non-small cell lung cancer (NSCLC) patients (Alfano et al., 2010; Clin Cancer Res 16:4401). NSCLC cells express the epidermal growth factor receptor (EGFR) whose tyrosine kinase activity is inhibited by gefitinib. Here the abillity of SR48692 to block EGFR transactivation caused by NTS was investigated. NTS and NTS8-13 but not NTS1-8 addition to NSCLC cell lines NCI-H1299 or A549 cells increased phosphorylation of Tyr1068 of the EGFR after 2 min which was blocked by 10 uM SR48692 or 10 ug/ml gefitinib. The ability of NTS to regulate EGF receptor transactivation was blocked by GM6001 (matrix metalloprotease inhibitor), PP2 (Src inhibitor), N-acetylcysteine (anti-oxidant) and transforming growth factor TGF) α antibody. By ELISA, NTS significantly increased secretion of TGFα from lung cancer cells. NTS but not levocabastine (NTSR2 agonist) increased cytosolic Ca2+ within seconds after addition to NCI-H1299 cells which was antagonized by SR48692. NTS addition to NCI-H1299 cells increased tyrosine phosphorylation of beta-catenin, ERK, FAK, PYK-2 and Src which was antagonized by SR48692. SR48692 inhibited the proliferation of NCI-H1299 and A549 cells which have wild type EGFR. Also, SR48692 potentiated the ability of gefitinib to inhibit growth of NCI-H1299 and A549 cells. These results indicate that SR48692 is a NTSR1 antagonist which increases the potency of gefitinib in lung cancer cells. Citation Format: Terry W. Moody, Robert T. Jensen. SR48692 inhibits EGF receptor transactivation and proliferation of lung cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1306. doi:10.1158/1538-7445.AM2013-1306