Figure 9

Stimulation of G _q -coupled receptors inhibits cell growth in Fhit-expressing cells. A, 293/Fhit and 293/vector cells, or H1299/Fhit and H1299/vector cells, which stably expressed Flag-tagged Fhit and the Flag tag alone (vector), respectively, were established as described in Methods. The expressions of Fhit were confirmed by Western blot. B, 293/vector or 293/Fhit cells were seeded into 96-well plates and 24 h later, the cells were treated with or without 100 μM carbachol in the growth medium (Day 0). MTT assay were performed on Day 0, 2, 4 and 6 to examine the relative viable cell number. Absorbance values on Day 0 were set as 1 for the respective group of cells. * Significantly different from that of the 293/vector cells without carbachol treatment on the same day; # carbachol treatment significantly inhibited the growth of 293/Fhit cells; Dunnett’s t test, p < 0.05, n = 8. C, H1299/vector or H1299/Fhit cells were seeded into 96-well plates and 24 h later, the cells were treated with or without 100 nM bombesin (Day 0). MTT assays were performed on Day 0 and 4. The values of MTT assay on Day 0 were set as 1 for the respective group of cells. * Bombesin significantly increased the growth of H1299/vector cells while it significantly inhibited the growth of H1299/Fhit cells; Dunnett’s t test, p < 0.05, n = 8.