Fig 2: PC4 destabilizes HIF-1α upon cisplatin treatment. (a) The HIF-1α protein level was determined by western blot in PC4-knockdown and PC4-overexpression LUAD cells. (b) Increasing concentrations of cisplatin were added into PC4-knockdown and PC4-overexpression LUAD cells for 24 hours. The HIF-1α protein expression was evaluated by western blot. ∗p < 0.05.

Fig 3: PC4 decreases lung adenocarcinoma cell sensitivity to DMOG and rapamycin. A-L PC4-knockdown or PC4-overexpression LUAD cells were treated with 1 µM A-485, 1 mM DMOG, 30 µM LY294002, 30 µM MG132, 10 µM MHY1485, or 30 nM rapamycin either alone or in combination with cisplatin. An individual cisplatin + DMSO control group was established for each drug. ∗p < 0.05.

Fig 4: a–c PC4 protein level and its interaction with CstF64 is constant during the cell cycle. a Western blot followed by immunodetection with anti-actin and anti-PC4 antibodies were performed using protein extracts isolated from asynchronous HeLa cells (AS) and cells synchronized to G1 and S phase. b Phos-tag™-based protein electrophoresis followed by Western blot and immunodetection with anti-PC4 antibodies using protein extracts isolated from asynchronous HeLa cells (AS) and cells synchronized to G1 and S phase. c Protein extracts isolated from cells synchronized to G1 and S phase were subjected to immunoprecipitation with anti-PC4 antibodies conjugated to protein A-magnetic beads or non-conjugated protein A-magnetic beads (mock) followed by Western blot and immunodetection with antibodies as indicated on the right. d–f PC4 influences cell proliferation. Charts represent the mean number of cells with PC4 KD (d) and PC4 OE (e) (n = 3). Additional cell proliferation test using MTT assay was performed on PC4 KD cells (f). HeLa scramble and PC4 KD cells were cultured with addition of doxycycline, 1st day of experiment represents 1st day of culture with doxycycline from the day the experiment started

Fig 5: Influence of PC4 on the levels of RDH mRNAs. RT-qPCR analysis of four selected RDH (and two RIH) genes was performed in PC4 OE (left panel) and PC4 KD (right panel) cells synchronized to S or G1 phase. Regions marked as described in Fig. 1c. Error bars indicate standard deviations (SD) of three biological replicates. P-values were calculated on relative level of expression values using Student’s T-test and statistical significance is represented as follows: *P ≤ 0.05