Figure 5. CHOP plays a role in fucoidan-inhibited cell viability.

(A) A549 cells were treated with fucoidan (400 μg/ml) for 0 to 48 h, and Western blotting analysis of whole-cell lysates was subsequently performed to detect CHOP expression. (B) A549 cells were treated with fucoidan (0 to 600 μg/ml) for 6 h, and Western blotting analysis of the CHOP expression in whole-cell lysates was subsequently performed. (C) HEK293T cells were transfected with three types of sh-CHOP plasmid (sh-#1, sh-#2 and sh-#3) to produce lentiviruses as described in the Materials and Methods section. After the media were harvested, viruses containing individual CHOP-shRNAs were used to infect A549 cells for 24 h followed by puromycin selection. CHOP expression was detected by Western blotting of whole cell lysates following TG (50 nM) treatment for 6 h. (D) A549 cells (scramble and CHOP-knockdown) were incubated with fucoidan (200 μg/ml) for 12 h, and Western blotting of whole-cell lysates was subsequently performed to detect CHOP expression. Actin was used as an internal control. (E) A549 cells (scramble and CHOP-knockdown cells) were treated with fucoidan (200 μg/ml) for 24 and 48 h. Cell viabilities were determined by crystal violet staining assays. Each group of fucoidan-treated samples was normalized against each untreated control. The data are representative of three separate experiments and are presented as the mean ± the SD. Error bars indicate the SD. Significant differences are noted (**P < 0.01 and ***P < 0.001, compared with the control group).