Figure 7. Depletion of GIPC in cells overexpressing LPA₁ promotes cell proliferation and cell motility.

A, GIPC-depleted HEK-LPA₁ cells (solid line) grow faster than those transfected with control (Ctrl) siRNA (_*, p<0.05). In contrast, GIPC depletion had little effect on the growth rate of HEK-pIRES cells which do not overexpress LPA₁. HEK-LPA₁ and HEK-pIRES cells were transfected with GIPC (siRNA) or control siRNA (Ctrl) and transferred to 96 well plates 24 h post-transfection. Cells were cultured for up to 72 h in medium containing 10% serum without puromycin. Cell number was determined as described in “Material and Methods”. Data are the mean ± s.e.m (n = 16 wells). B, Depletion of GIPC promotes HEK-LPA₁ cell motility. Serum starved HEK-LPA₁ cells were transfected with either GIPC (white bars) or control (black bars) siRNAs and allowed to migrate for 3 h on fibronectin-coated filters. LPA (1 µM) was added to the bottom chambers in half the wells. The number of migrating cells was determined by counting cells on the underside of the filters as described in “Material and Methods”. Each bar represents the mean ± s.e.m. of triplicate wells in three independent experiments.