ML-18 is a non-peptide bombesin receptor subtype-3 (BRS-3) antagonist with an IC50 of 4.8 μM.

BRS3:4.8 μM.

ML-18以16 μM浓度，通过使用加载了FURA2-AM的肺癌细胞，可可逆性地抑制10 nM BA1提高细胞内Ca2+的能力。相同浓度下，ML-18能够抑制100 nM BA1引起的肺癌细胞中EGFR和ERK的酪氨酸磷酸化，进而抑制肺癌细胞的增殖。此外，ML-18还具有抑制具体125I-BA1（DTyr-Gln-Trp-Ala-Val-βAla-His-Phe-Nle-NH2）BB6-14与稳定转染BRS-3的NCI-H1299肺癌细胞结合的能力，其IC50值为4.8 μM。而对GRPR和NMBR的亲和力较低，其IC50值分别为16 μM和超过100 μM。

The cells are incubated in SIT buffer containing 0.25% bovine serum albumin and 250 μg/mL bacitracin and 125I-BA1 (100,000 cpm) is added, as well as various concentrations of unlabelled competitor (ML-18). After incubation at 37°C for 30 min, free 125I-BA1 is removed by washing 3 times in buffer and the cells which contain bound 125I-BA1 is dissolved in 0.2 N NaOH and counted in a gamma counter. The IC50 is calculated for each unlabeled competitor.

ML-18 is dissolved in DMSO at a concentration of 10 mM prior to use. Cell viability is measured using the MTT assay. NCI-H727 or NCI-H1299 cells transfected with BRS-3 are treated with ML-18 (0, 4.8, 16, 48 μM) or gefitinib added. After 2 days, 15 μL of 0.1 % MTT solution added. After 4 h, 150 μL of DMSO is added. After 16 h, the optical density at 570 nm is determined.