Figure 3.

CCN1 induces apoptosis through integrin α₆β₁ and HSPGs. (A) Cells were pretreated with 1 mg/ml heparin for 1 h in serum-free medium or with 20 mM Na₂SO₄ and/or 100 mM NaClO₃ for 24 h in media containing 10% FBS, after which cells were washed and subjected to further incubation with or without 10 μg/ml CCN1 in serum-free medium containing the pretreatment level of Na₂SO₄ and/or NaClO₃. (B) Cells were pretreated with 100 μg/ml of control rabbit IgG or 100 μg/ml anti–syndecan-4 antibody for 1 h in serum-free medium before incubation with or without CCN1. (C) Cells were pretreated with the peptides T1 (4 mM), T1-mut (4 mM), H2 (5 mM), or T4 (5 mM) for 1 h before further incubation with or without 10 mg/ml CCN1. (D) Cells were pretreated with 40 μg/ml GoH3, an mAb against integrin α6, or 40 μg/ml of control mouse IgG for 1 h before incubation with or without CCN1. (E) Cells were pretreated for 1 h with GRGDSP and GRGESP peptides (0.2 mM) before further incubation with or without CCN1. Error bars represent ± SD from experiments done in triplicate.