BW-2258-U89

The effects of some oncogenes, growth factors and neuropeptides are mediated by tyrosine phosphorylation of focal adhesion kinase (p125(FAK)) and paxillin cytoskeletal proteins. In this study the ability of bombesin/gastrin releasing peptide (BB/GRP) to stimulate tyrosine phosphorylation of p125(FAK) and paxillin in non-small cell lung cancer (NSCLC) H1299 cells was investigated. BB, 100 nM caused increased p125(FAK) and paxillin tyrosine phosphorylation maximally after 1 min. The effect of BB on p125(FAK) and paxillin tyrosine phosphorylation was concentration-dependent, being half maximal at 4-8 nM. Also, 100 nM GRP, GRP(14-27) but not GRP(1-16) increased p125(FAK) and paxillin tyrosine phosphorylation indicating that the C-terminal of GRP is essential. BW2258U89, a GRP receptor antagonist, caused a dose-dependent inhibition of BB-stimulated p125(FAK) and paxillin tyrosine phosphorylation with an IC50 value of 3 microM. Cytochalasin D (0.3 microM), which inhibits actin polymerization, reduced the ability of BB to stimulate tyrosine phosphorylation of p125(FAK) and paxillin. Genistein (50 microM) and H-7 (50 microM), which are kinase inhibitors, reduced the tyrosine phosphorylation of p125(FAK) and paxillin stimulated by BB. Also, treatment of NCI-H1299 cells with FAK antisense resulted in decreased FAK tyrosine kinase activity and proliferation. These results suggest that p125(FAK) is an important enzyme for NSCLC proliferation.

BW2258U89 is a gastrin releasing peptide (GRP) receptor antagonist which inhibits the proliferation of the neuroendocrine tumor small cell lung cancer (SCLC). Here the biological activity of BW2258U89 and its metabolite were investigated. Using mass spectroscopy (LC-ESI/MS) techniques, three major peaks for BW2258U89 were observed with mass/charge (m/z) ratios of 1081.6, 541.4 and 361.4. After metabolism by mouse plasma enzymes, the major product had a m/z ratio of 1082.5, 541.9 and 361.8 suggesting that BW2258U89 was deamidated. Deamidated (Da) BW2258U89 was synthesized and it inhibited ((125)I-Tyr(4)) BB binding to NCI-H345 SCLC cells with an IC(50)value of 450 nM; BW2258U89 had an IC(50)value of 17 nM. BW2258U89 (1 microM) antagonized the ability of 50 nM BB to elevate cytosolic Ca(2+)in NCI-H345 cells, whereas 1 microM (Da) BW2258U89 did not. One micromolar BW2258U89 antagonized the increase in NCI-H345 c-fos mRNA caused by 10 nM BB, whereas 1 microM (Da) BW2258U89 had little effect. One microM BW2258U89 inhibited NCI-H345 clonal growth significantly whereas 1 microM (Da) BW2258U89 did not. These data suggest that an amidated C-terminal is important for antagonism of SCLC GRP receptors by BW2258U89.