Fig. 1

HPV16/18 E7 induces LDHA nuclear translocation by ROS accumulation. a LDHA is significantly translocated into nucleus in HPV16 positive cervical cancer tissues. Representative IHC images for LDHA localization in HPV16-negative and positive cervical tumor samples. Scale bar, 100 μm. b Nuclear LDHA is dramatically increased in HPV16-positive cervical cancer tissues. Semi-quantitative cytoplasmic LDHA and nuclear LDHA scoring was performed in HPV16 negative (n = 27) and positive (n = 39) cervical tumor samples. c, d HPV16/18 E7 promotes LDHA nuclear translocation in a ROS-dependent manner. Primary human cervix keratinocytes (PHKs) stably expressing vector or Flag-tagged HPV16/18 E7 were treated with or without 1 mM NAC for 6 h, followed by staining with anti-LDHA (green), anti-Flag (red) antibodies, and DAPI (blue). Scale bars, 10 μm (c). The percentage of cells with nucleus-localized LDHA compared to total cell number was quantified (d). e HPV16/18 E7 enhances ROS production. Cellular ROS were measured in PHKs stably expressing vector or HPV16/18 E7 coupled with or without 1 mM NAC treatment for 6 h, followed by using the ROS-sensitive fluorescent dye (CM-H₂DCFDA) with flow cytometry according to the manufacturer’s protocol. f, g LDHA nuclear translocation is profoundly increased in an H₂O₂-dose-dependent manner. Immunofluorescent images of LDHA (green) in HaCaT cells upon different dose of H₂O₂ treatment as indicated. DAPI, blue. Scale bars, 10 μm (f). The percentage of cells with nucleus-localized LDHA compared with total cell number was quantified (g). h ROS promote LDHA nuclear translocation. HT-3 cells were treated with or without 10 μM H₂O₂ for 6 h, and supplemented with or without 1 mM NAC for extended 6 h as indicated for nuclear isolating, followed by blotting with LDHA, Tubulin, and Lamin B1. Results are representative of three independent experiments. All data are shown as mean ± SEM. The p values were determined by two-tailed t-test. The values of p < 0.05 were considered statistically significant. *, **, and *** denote p < 0.05, p < 0.01, and p < 0.001, respectively. NS means non significant