Figure 6. OGT knockdown increases sensitivity of HeLa cells to cisplatin.

(A) HeLa cells transfected with non-specific (shCTL) or OGT-specific shRNA (shOGT) constructs were treated with different concentrations of cisplatin (5, 10, 20, 40, or 80 μM) for 24 h. Cell metabolic activity was measured using a MTT assay to determine the rate of HeLa cell death in response to cisplatin. Percent cell survival is presented as mean ± S.E.M. (n = 16). ^**p < 0.01 and ^***p < 0.001, vs. shCTL. (B) HeLa cells transfected with shCTL or shOGT were treated with 20 μM of cisplatin for 24 h and stained with TUNEL. Percentages of TUNEL-positive cells are presented as mean ± S.E.M. (n = 3). ^**p < 0.01. (C) shCTL HeLa and shOGT HeLa cells (1 × 10⁵ cells/ml) were treated with cisplatin (20 μM) for 24 h. Following treatment, cells were harvested, fixed, and stained with PI, then analysed by flow cytometry. Bar diagram indicates the percentage of cells in the SubG₁ phase of the cell cycle. Data are presented as mean ± S.E.M. (n = 3). ^**p < 0.01. (D) shCTL HeLa or shOGT HeLa cells were stained with Annexin V-FITC and PI after cisplatin treatment, then analysed by flow cytometry. Experiments were performed three times separately.