Figure 4.

LPA₁ and S1P₁ regulate HT1080 invasion of 3D collagen matrices in response to LPA and S1P, respectively. (A) HT1080 cells were allowed to invade in the presence of either LPA or S1P (1 μM) in the presence (+) or absence (-) of 100 ng/μl of pertussis toxin (PTX). Cells were fixed, stained, and quantitated as described in Fig. 2. (B) HT1080 cells were transfected with siRNAs targeting the indicated genes and allowed to invade in the presence of either LPA or S1P (1 μM). Data are reported as mean numbers of invading cells per HPF (20×) (± S.D.) from a minimum of 20 fields. Statistical significance of means was determined using t-test where * = p < 0.01 relative to Luciferase (Luc) control for each lipid. (C) Real-time Quantitative PCR (RTQ-PCR) values for LPA₁ and S1P₁ mRNA normalized against 18S RNA were used to illustrate selective targeting of the designated siRNA.