Abstract:
OBJECTIVE To explore the effect of Oridonin (Ori) on proliferation, apoptosis and mitophagy of triple negative breast cancer (TNBC) and its specific mechanism.
METHODS CCK8 method was used to explore the effect of Ori on the activity of triple negative breast cancer MDA-MB-231 cells and determine the concentration of drugs that can effectively inhibit the growth of tumor cells. The effects of Ori on apoptosis and Reactive Oxygen Species (ROS) were detected by flow cytometry. Western blot was used to detect the expression of cell apoptosis -related proteins Caspase-9, Bax and mitophagy-related proteins LC3B, p62, PINK1 and Parkin. MDC staining was used to observe whether autophagy occurred in MDA-MB-231 cells after drug intervention; immunofluorescence was used to detect the expression of LC3B, PINK1 and Parkin proteins in cells and their co-location with mitochondria. The effects of Ori on proliferation and autophagy of TNBC were verified by subcutaneous transplantation of tumor animals.
RESULTS Ori could significantly inhibit the activity of TNBC cells, and the IC50 was 20.57 μmol·L-1. At the same time, Ori could significantly promote cell apoptosis (P<0.001) and increase ROS content in cells (P<0.05), up-regulate the expression of cell apoptosis-related proteins Bax (P<0.01), and up-regulated the expression of activated Caspase-9 protein (P<0.01). In addition, Ori could promote autophagy in TNBC cells, up-regulate the expression of autophagy-related proteins LC3B Ⅱ/Ⅰ and p62 (P<0.05, P<0.001), and up-regulated the expression of mitophagy-related proteins PINK1 and Parkin (P<0.01) and their co-localization with mitochondria. . The animal experiment of subcutaneous transplanted tumor confirmed that compared with the control group, the high-dose Ori group could significantly inhibit tumor growth and promote mitophagy of tumor cells.
CONCLUSION Ori induces mitophagy in triple negative breast cancer through PINK1/Parkin pathway, which inhibits tumor growth.