In vitro activity: Ki16198 or Ki16425 substantially inhibits LPA1- and LPA3-mediated responses with a similar potency, with low potency to LPA2 and no activity to LPA4, LPA5 and LPA6. Ki16198 (10 μM) is also effective to inhibit migration and invasion responses to LPA in YAPC-PD cancer cell line with a potency similar to that of Ki16425. Ki16198 (10 μM) inhibits the LPA-induced expression of proMMP-9 protein and mRNA in YAPC-PD cells. Ki16198 (1 μM) inhibits the proliferation of lpa1Δ-1 and lpa1Δ+-1 cells by about 70%.

Kinase Assay: RH7777 cells expressing LPA1, LPA2, LPA3, LPA4, or LPA5 are cultured on collagen-coated 12-well dishes in the growth medium, and then the medium is changed to TCM199 containing 2 μCi/mL [3H]inositol and 0.1% (w/v) BSA (fraction V). After 24 h later, the cells are washed three times with HEPES-buffered medium, which consisted of 20 mM Hepes (pH 7.4), 134 mM NaCl, 4.7 mM KCl, 1.2 mM KH2PO4, 1.2 mM MgSO4, 2 mM CaCl2, 2.5 mM NaHCO3, 5 mM glucose, and 0.1% (w/v) BSA, and incubated for 30 min with the indicated concentrations of Ki16425 or Ki16198 with or without 1 μM LPA in the presence of 10 mM LiCl in the same medium at final volume of 0.5 mL. The reaction is terminated by adding 1 N HCl (0.1 mL) and freezing the cells. The supernatant (acid extract in 0.5 mL) of the thawed cells is used for the separation of [3H]inositol phosphate fractions. The results are normalized to 105 dpm of the total radioactivity incorporated into the cellular inositol lipids. The radioactivity of the trichloroacetic acid (5%)-insoluble fraction is measured as the total radioactivity.

Cell Assay: YAPC-PD cells or Panc-1 cells are seeded on 12-well plates at 1 × 104 cells in 1 mL. Sixteen hours before experiments, the medium is changed to RPMI1640 containing 0.1% BSA. Then, the cells are stimulated for 24 h in the same medium in the presence or absence of Ki16198. The proliferation activity is measured by the cellular ability to reduce MTT (3-(4,5-Dimethyl-2-thiazoyl)-2,5-diphenyltetrazolium bromide.

Cancer Sci. 2012 Jun;103(6):1099-104; Cardiovasc Res. 2011 Oct 1;92(1):149-58.