Abstract

Background Isatin derivatives have extensive biological activities, such as antitumor. IF203, a novel isatin derivative, has not previously been reported to have antitumor activity. Methods Acid phosphatase assays (APAs) and Ki-67 immunohistochemistry were used to detect the proliferation of HepG2 cells. Transmission electron microscope (TEM) was applied to detect ultrastructural changes. Flow cytometry (FCM) was used to detect cell cycle, apoptosis, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) of HepG2 cells in vitro. TUNEL, MMP and ROS immunofluorescence assays were applied to assess apoptosis, MMP, and ROS of HepG2 cells in vivo. Western Blotting was applied to assess the levels of apoptosis- and autophagy-related proteins. Results In this study, in vivo and in vitro experiments showed that IF203 possesses antitumor activity. The results of APAs and Ki-67 immunohistochemistry demonstrated that IF203 could inhibit the proliferation of HepG2 cells. Cell cycle assays, downregulation of Cyclin B1 and Cdc2, and upregulation of P53 suggested that IF203 could lead to G2/M cell cycle arrest. In addition, ultrastructural changes, apoptosis assays, TUNEL immunofluorescence results, upregulated expression of Bax, and downregulated expression of Bcl-2 suggest that IF203 can induce apoptosis in HepG2 cells. After IF203 treatment, intracellular ROS levels increased, MMP decreased, JC-1 green fluorescence was enhanced, and the levels of Caspase-9, Caspase-3 and Cytochrome C expression were upregulated, suggesting that IF203 could induce apoptosis of HepG2 cells through the mitochondrial apoptosis pathway. Moreover, characteristic apoptotic ultrastructural changes were accompanied by the appearance of many autophagy bubbles and upregulation of Atg5, Atg12, ULK1, Beclin-1 and LC3-II proteins, suggesting that IF203 could induce autophagy in HepG2 cells. Conclusion This study showed that IF203 leads to the death of HepG2 cells through cell cycle arrest,