Abstract: Objective To investigate the effect of Dictamnine on proliferation, apoptosis and autophagy of ovarian cancer cells and its mechanism. Methods Human ovarian cancer cell lines (A2780, PA⁃1) and human normal ovarian epithelial cell lines (IOSE80) were treated with Dictamnine of different concentrations (0, 32, 65, 125, 250 μmol/L), and the IC₅₀ values of each cell were detected by CCK⁃8 assay. The core targets of Dictamnine for ovarian cancer were screened out by network pharmacology, and molecular docking was used to assess the binding ability. A2780 cells were selected and treated with Dictamnine (0, 50, 75 μmol/L). The effects of Dictamnine on cell proliferation, apoptosis and autophagy of A2780 cells were analyzed by CCK⁃8 assay, HE staining, Annexin V⁃FITC/PI double staining and Western blot. The effect of Dictamnine on the growth of ovarian cancer grafts in nude mice was observed. The tissue morphology and ultrastructure of the grafts were observed by HE staining and transmission electron microscopy (TEM), and the expression levels of Cleaved PARP and Ki67 in the grafts were detected by immunohistochemical staining (IHC). Results The results of CCK⁃8 assay showed that the IC₅₀ of Dictamnine on A2780 cells and PA⁃1 cells were significantly lower than those of IOSE80 cells, with the strongest inhibitory effect on A2780 cells. The proliferation ability of A2780 cells in Dictamnine (50 μmol/L, 75 μmol/L) treatment groups was significantly decreased compared with untreated cells (all P<0.05). The ten core targets of Dictamnine against ovarian cancer were screened by network pharmacology, and the targets with strong binding ability were PIK3CD, KEAP1 and AHR. Flow cytometry results showed a significant increase in apoptosis rate in A2780 cells after treatment with Dictamnine for 48 h and 72 h (all P<0.01).Western blot analysis showed that compared with the untreated group, the expression levels of A2780 cells apoptosis⁃related proteins Cleaved PARP and PARP were significantly increased, the expression levels of autophagy⁃related proteins SQSTM1/p62 and KEAP1 were decreased, the ratio of LC3B Ⅱ/Ⅰ expression levels were increased, and expression levels of PI3K signaling pathway protein PI3K was decreased (all P<0.05). After Dictamnine treatment, the volume of transplanted tumors in nude mice decreased significantly (P=0.0053), tumor tissue showed obvious apoptotic cells under TEM, and IHC results showed a decrease in Ki67 expression level and an increase in Cleaved PARP expression level (all P<0.001). HE staining demonstrated that Dictamnine⁃treated A2780 cells exhibited a short spindle⁃shaped or ovoid⁃shaped with reduced volume, and the apoptotic/necrotic cells were present in grafts. Conclusions Dictamnine probably inhibit proliferation of ovarian cancer cells and induce autophagy and apoptosis by targeting the PI3K/KEAP1 signaling pathway.

Key words: Ovarian Cancer, Dictamnine, Proliferation, Apoptosis, Autophagy, Network Pharmacology