Fig. 6: CBX4 promotes the proliferation of LUAD via transcriptional activation of PHGDH.

A Western blot analysis of the expression of PHGDH, CBX4, and β-actin in A549 cells expressing control or CBX4 shRNAs. The levels of a-KG (B) and NADPH (C) in the cell lysate from A549 cells expressing control or CBX4 shRNAs were detected by HPLC and spectrophotometry, respectively. D Western blotting of cell lysates from A549 cells expressing control or PHGDH shRNAs, using PHGDH and β-actin antibodies. E MTT assays were performed in A549 cells expressing control or PHGDH shRNAs. F Colony formation assays were conducted in A549 cells expressing control or PHGDH shRNAs. The number of colonies was counted. G EdU-incorporation assays were performed in indicated cells, and the percentage of EdU-positive cells was calculated. Scale bar, 100 μm. For figures B, C and E–G, each bar represents the mean ± SD for n = 3; *P < 0.05, **P < 0.01, ***P < 0.001 versus control (Student’s t-test). H A549 cells stably expressing control shRNA or CBX4 shRNA-1 were transfected with Flag-PHGDH expression constructs or empty vectors. The mRNAs were extracted, and subjected to real-time quantitative RT-PCR assays. I MTT assays were performed in the indicated cells. J EdU-incorporation assays were performed in the indicated cells. Scale bars, 100 μm. For figures H–J, each bar represents the mean ± SD for n = 3; *P < 0.05, ***P < 0.001 (one-way ANOVA followed by Bonferroni post-hoc test or Tambane’s T2 post-hoc test).