Fig. 3

Overexpression of C/EBPα-p42 and C/EBPα-p30 in AML cells differently regulates the UPR genes and cell susceptibility to ER stress mediated apoptosis. A The pattern diagram of C/EBPα-p42 and C/EBPα-p30 protein translations. B Western immunoblotting analysis of endogenous expression of C/EBPα two isoforms and DDIT3 in AML cell lines. C-D The C/EBPα protein level in NB4 cells, with low endogenous C/EBPα expression and relatively high sensitivity to tunicamycin, was induced by the expression vectors of C/EBPα-p42 (pHIV7/SFFV-GFP-C/EBPα-p42) and C/EBPα-p30 (pHIV7/SFFV-GFP-C/EBPα-p30). The up-regulated levels of C/EBPα, and the correspondingly altered DDIT3 expression were confirmed by quantitative PCR (C) and western immunoblotting analysis (D). E Quantitative PCR revealed that the expression levels of the pro-survival genes GRP94 and XBP1u were significantly decreased in NB4 cells with induction of C/EBPα-p30. F Compared with the vector control, the apoptosis rate of NB4 cells overexpressing C/EBPα-p42 was significantly reduced after the treatment with tunicamycin (100 ng/ml) for 48 h. G-H The C/EBPα protein level in THP-1 cells was induced by the expression vector of C/EBPα-p30 (pHIV7/SFFV-GFP-C/EBPα-p30). The up-regulated levels of C/EBPα-p30, and the correspondingly altered DDIT3 expression were confirmed by quantitative PCR (G) and western immunoblotting analysis (H). I Compared with the vector control, the apoptosis rate of THP-1 cells overexpressing C/EBPα-p30 was significantly increased after the treatment with tunicamycin (100 ng/ml) for 48 h. Data represent Mean ± SD (n = 3); *P < 0.05; **P < 0.01, ***P < 0.001, ****P < 0.0001