CBP induced ER stress in HEp2 and 7T cells.

<p>(A) HEp2 and 7T cells were pretreated for two hours with 12.5 µM salubrinal, and then treated with different concentrations of CBP. Seventy-two hours later cell survival was measured by MTT assay. Representative data of three independent experiments are presented (mean ±SD). *Significantly different from the respective control. * p<0.05. (B) HEp2 and 7T cells were treated with 80 µg/mL CBP or 10 µg/mL tunicamycin for 4 and 8 h. At indicated time points the cells were collected and the expression of ATF4, phospho-eIFα (p-eIFα), eIFα and XBP-1 was determined. (C) HEp2 and 7T cells were treated with 40 µg/mL CBP or 1 µg/mL tunicamycin during 16 and 24 h. At indicated time points the cells were collected and the expression of ATF4 was determined. ERK2 control was used as an internal loading control. Data of one of two experiments that yielded similar results are presented. Densitometric analysis data are expressed as a ratio between examined ER markers and ERK2. Non treated cells were set as 1.0.