RESUMO
@#To investigate the expression of polyadenosine diphospho-ribose polymerase 1 (PARP-1) and p16/ retinoblastoma (Rb) protein in hydroquinone (HQ)-induced TK6 cells and their regulatory mechanisms. Methods According to the 2×2 factorial design model, TK6 cells were divided into PBS-TK6 group and HQ-TK6 group based on HQ exposure, and then sub-divided into non-DOX intervention subgroup and DOX intervention subgroup based on DOX intervention, a total of four groups. The PBS-TK6 group was treated with phosphate buffer saline, and the HQ-TK6 group was treated with HQ at a final concentration of 20.0 μmol/L. The non-DOX intervention subgroup was added with 0.05% dimethyl sulfoxide; and the DOX intervention subgroup was added with PARP-1 agonist DOX at a final concentration of 0.5 μmol/L. The distribution of cell cycle was detected by flow cytometry. The protein expression of p16/Rb, cyclin D1 (cyclinD1), multifunctional protein E2 transcription factor 1 (E2F1), Rb, and p-Rb were detected by Western blot, and the level of p16 ribosylation was detected by immunofluorescence and immunoprecipitation. Results Compared with the PBS-TK6 group, the cell cycle distribution percentage in G0/G1 phase and the relative expression levels of p16 proteins were decreased in the cells of the HQ-TK6 group (all P<0.05). The cell cycle distribution percentage in S phase and the relative expression levels of cyclinD1 and p-Rb proteins were up-regulated (all P<0.05). Compared with the non-DOX intervention group, the cell cycle distribution percentage in G0/G1 and G2/M phases and the relative expression level of p16 protein increased in the DOX intervention group (all P<0.05). The percentage of cells in S phase and the relative expression levels of cyclinD1 and p-Rb proteins were down-regulated (all P< 0.05). The results of interaction effect analysis showed that compared with the non-DOX PBS-TK6 cells, the relative expression levels of Rb and E2F1 protein in the DOX PBS-TK6 cells intervention group were down-regulated (all P<0.05). The relative expression level of Rb protein in non-DOX HQ-TK6 cell group was down-regulated (P<0.05), and the relative expression of E2F1 protein was up-regulated (P<0.05). Compared with DOX PBS-TK6 cell group, the relative expression level of Rb protein in DOX HQ-TK6 cell group was down-regulated and that of E2F1 protein was up-regulated (all P<0.05). Compared with the non-DOX HQ-TK6 cell group, the relative expression level of Rb protein in the DOX HQ-TK6 cell group was up-regulated and that of E2F1 protein was down-regulated (all P<0.05). Conclusion PARP-1 participates in cell cycle regulation by regulating the p16/Rb signaling pathway in TK6 cells.