Lysophosphatidic Acid Triggers Apoptosis in HeLa Cells through the Upregulation of Tumor Necrosis Factor Receptor Superfamily Member 21

Figure 4

PI3K, PKC, and MEK pathways are involved in LPA-induced DR6 expression. (a) HeLa cells were treated with LPA (25 μM) in the presence or absence of the pathway inhibitors as indicated. The phosphorylation of MEK, ERK, and p90RSK was analyzed by Western blotting. The blot is a representative of 3 independent experiments. The bar graphs on the right panel are densitometry analyses of MEK, ERK, and p90RSK phosphorylation levels. versus control; versus LPA-treated group. (b) HeLa cells were treated with LPA in the presence or absence of the pathway inhibitors as indicated and the expression of DR6 was measured by Northern blot. The bar graphs on the right panel are statistical analysis of DR6 expression. Data presented are mean ± SD from 3 independent experiments, with untreated controls set as 1. versus control; versus LPA alone; versus LPA-treated group. PTX, pertussis toxin (100 ng/mL); GF10293X, PKC inhibitor (5 μM); wortmannin, PI3K inhibitor, (100 nM); Ro 31-8220, PKC inhibitor (5 μM); U-0126, MEK inhibitor (10 μM); SB203580, p38 inhibitor (2.5 μM) and JNK inhibitor (10 μM).

(a)

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