RAD51 potentiates synergistic effects of chemotherapy with PCI-24781 and cis-diamminedichloroplatinum on gastric cancer

Figure 3 PCI-24781 modulates the genes related to DNA damage and repair. A: Propidium iodide/fluorescence activated cell sorting analysis showed the effect of the histone deacetylase inhibitor (0.5 μmol/L PCI-24781, 24 h) on HGC27 cell cycle progression. A significant (P < 0.05) reduction in the number of S phase cells and a G2 arrest was observed; The increased sub-G1 population also indicated more apoptotic cells; B, C: Treatment with 0.5 μmol/L PCI-24781 induced a time-dependent decrease in RAD51, both at the mRNA and protein levels; D, E: The confocal laser scanning microscopy immunofluorescence images show HGC27 cells stained with an anti-FK2 antibody (DNA damage marker) and an anti-RAD51 antibody (homologous recombination marker) after pretreatment with 0.1 μmol PCI-24781 for 24 h, followed by 5 Gy irradiation (IR); images were captured 16 h after irradiation. PCI-24781 notably increased the amount of DNA damage-induced ubiquitin conjugation on chromatin (FK2 positive) and suppressed RAD51 foci formation. GAPDH: Glyceraldehyde-3-phosphate dehydrogenase.