Figure 4.

Effect of rECP-induced apoptosis on ER response. BEAS-2B cells were treated with rECP or thapsigargin (TG; an ER toxin as a positive control) for the indicated times. The cells used to determine the ER response were incubated with 20 μM rECP or 1 μM TG for 0, 4, 8, 12, 16, 20 and 24 h. (A) Total cell lysates were resolved by 10% SDS-PAGE, and the relative accumulated GRP78 was investigated by western blotting with anti-GRP78 and anti-actin. (B) For de novo proteins synthesis, cells were labeled with [³⁵S]methionine for 2 h before harvesting. Equal amounts of labeled cell lysates were resolved by 10% SDS-PAGE followed by quantitative analysis. All data represent the arithmetic mean ± SEM. *P < 0.05.