Figure 2. Chloroquine and blocking antibodies against TGF-β normalize furin activity in CF cells.

Cells were incubated in full medium with 10 ng/ml TGF-β1 or in the presence of 5 μg/ml TGF-β antibodies or were treated with 0.1 mM chloroquine (CQ). (A) IB3-1 (CF) and S9 (CFTR corrected) cells. (B) pCEP-R (overexpressing the CFTR R domain) and pCEP (mock-transfected) cells. (C) CFBE (CF) and 16HBE (normal) cell lines. (D) Additionally, furin levels were normalized with 100 nM bafilomycin A₁ (BA) or 50 μM furin inhibitor (CMK) in primary (CF and normal) human lung epithelial cells. Data are presented as percentage of furin, where 100% corresponds to furin activity in non-CF cells (n = 3 experiments). Mean ± SEM (*P < 0.05, **P < 0.01).