Fig. 7.

PSAT1 is a target of ATF4 in ER-negative breast cancer. a Expression profile of ATF4 in ER-negative breast cancer tissues (n = 179) and ER-positive breast cancer tissues (n = 601) (TCGA). b Relative expression of ATF4 in ER-negative breast cancer tissues (n = 179) in comparison with non-tumor normal tissues (n = 114) (TCGA). c Correlation between PSAT1 and ATF4 mRNA expression in samples from 179 patients with ER-negative breast cancer from the TCGA database. d Real-time PCR analysis show ATF4 siRNA inhibited the mRNA expression of PSAT1 in MDA-MB-468 and BT-549 cells compared to negative control cells. . These results were normalized to the expression of β-actin. The values of the NC group were normalized to 1. e Western blot shows PSAT1 expression was decreased in ATF4 silenced MDA-MB-468 and BT-549 cells compared to negative control cells. f The growth rate of the indicated cells was evaluated using a CCK-8 assay. g Schematic representation of the predicated ATF4 binding site within the PSAT1 promoter. h RT-PCR of the ChIP products validated the binding capacity of ATF4 to the PSAT1 promtor. The results of IgG were normalized to 1. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. TCGA = The Cancer Genome Atlas; BRCA = Breast carcinoma