Figure 4.

Bcl-2 but not Bax is involved in regulating laminin-induced ASM cell survival. Bcl-2 (A–C) or Bax (D–F) protein abundance was measured following 7- or 6-d serum deprivation in the presence or absence of selective laminin-competing peptide YIGSR (A, D), various types of laminin coating (B, E) or integrin α7 siRNA (C, F). Experiments were terminated after 6-d serum deprivation based on preliminary experiments, which showed effective silencing of integrin α7 mRNA and protein expression for ≥6 d for siRNA experiments. Results are representative of 3 independent experiments. α2, affinity-purified α2-chain laminin from human placenta, which includes laminin-211 and -221; EHS, laminin from EHS murine sarcoma consisting mainly of laminin-111. GFP served as negative control; TA served as vehicle control. Data are expressed as fold increment over basal (d 0) relative to β-actin protein abundance. *P < 0.05 vs. d 0; ^†P < 0.05 vs. d 7 response in absence of peptide or laminin coating or d 6 response without integrin α7 siRNA.