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. 2021 Aug 4;13(16):3936. doi: 10.3390/cancers13163936

Figure 4.

Figure 4

Reduced expression of CHIP sensitizes ErbB2-overexpressing breast cancer cell lines to ER stress. (A) SKBR3 and 21MT1 cells were seeded in six-well plates and incubated with ER stress inducer thapsigargin (50nM) for 24 h. Cleared lysates (50 μg protein/lane) were left untreated or treated with lambda protein phosphatase (400U) for 30 min and then subjected to Western blotting for GRP78, PERK and Hsc70 (loading control). (B,C) SKBR3 (B) and 21MT1 (C) cells were seeded in six-well plates and incubated with indicated concentrations of thapsigargin for 24 h. Cleared lysates (50 μg/lane) were subjected to Western blotting for ErbB2, GRP78, phospho-eIF2α, PERK, CHIP and Hsc70 (loading control). (D) SKBR3 and 21MT1 cells were seeded in soft agar (0.6% bottom layer, 0.35% top layer) in six-well plates and treated with the indicated concentrations of thapsigargin for 2 weeks. Data represent mean ± SD, n = 3, * p < 0.05.