Lumacaftor (VRT 826809) is a CFTR modulator that corrects the folding and trafficking of CFTR protein. It enhances F508del-CFTR protein maturation in FRT cells (EC50: 100 nM).

F508del CFTR:0.1 μM (EC50, Fischer rat thyroid cells)

在培养的源于F508del基因同型突变CF患者的人类支气管上皮细胞中，Lumacaftor（VX-809）改善了F508del-CFTR在内质网的处理，并将氯离子分泌提升到非CF人类支气管上皮细胞的约14%（EC50：81 nM），此水平与携带较少干扰CFTR突变的轻度CF患者相关[1]。VX-809在与细胞共孵育时，不论是在37°C还是27°C，都能在两种细胞系中产生浓度依赖性地增加HRP发光信号，其EC50值相似，约为0.3 μM [2]。

In one set of assays, R1070W-?F508-CFTR-HRP (R1070W-HRP)–expressing CFBE41o? cells were incubated with 100 μl medium containing 25 μM test compounds and 0.5 μg/ml doxycycline for 24 hours at 37°C. In a second set of assays, ?F508-CFTR-HRP (?F508-HRP)–expressing CFBE41o? cells were incubated with 100 μl medium containing 25 μM test compounds, 2 μM VX-809, and 0.5 μg/ml doxycycline for 24 hours at 37°C. All compound plates contained negative controls (DMSO vehicle) and positive controls [2 μM VX-809]. In both assays, the cells were washed four times with PBS, and HRP activity was assayed by the addition of 50 μl/well of HRP substrate. After shaking for 5 minutes, chemiluminescence was measured using a Tecan Infinite M1000 plate reader (Tecan Groups Ltd, Mannedorf, Switzerland) equipped with an automated stacker (integration time, 100 milliseconds). Z′ is defined as = 1 ? [(3 × standard deviation of maximum signal control + 3 × standard deviation of minimum signal control)/absolute (mean of maximum signal control ? mean of minimum signal control)] [2].

FRT, HEK-293, or HBE cells expressing CFTR or F508del-CFTR were incubated for 24 h at 37 °C with or without VX-809 in the assay media. After incubation, cells were harvested in ice-cold D-PBS solution (without calcium and magnesium) and pelleted at 1,000 × g at 4 °C. Cell pellets were lysed in 1% Nonidet P-40, 0.5% sodium deoxycholate, 200 mM NaCl, 10 mM Tris, pH 7.8, and 1 mM EDTA plus protease inhibitor mixture (1:250) for 30 min on ice. Lysates were spun for 10 min at 10,000 × g at 4 °C to pellet nuclei and insoluble material. Approximately 12 μg total protein was heated in Laemmli buffer with 5% β-mercaptoethanol at 37 °C for 5 min and loaded onto a 3% to 8% Tris-acetate gel. The gel was transferred to nitrocellulose and processed for Western blotting by using monoclonal CFTR antibody 769 or polyclonal to GAPDH. Blots were developed by enhanced chemiluminescence. Quantification of the relative amounts of bands C and GAPDH was performed by using NIH ImageJ analysis of scanned films [1].