Tanshinone I inhibits metastasis of cervical cancer cells by inducing BNIP3/NIX-mediated mitophagy and reprogramming mitochondrial metabolism

Background: Cervical cancer is the most common malignancy of the female lower genital tract. Tanshinone I (Tan I) is one of the crucial lipid-soluble components of red sage (Salvia miltiorrhiza). While its mode of action against cervical cancer is unclear. Purpose: Our study aimed to explore the role of Tan I on cervical cancer in vitro. Study design and methods: Effects of Tan I on cervical cancer cells viability, migration and mitochondrial function were investigated by Cell Counting Kit-8, Transwell and Fluorescence laser confocal microscope assays respectively. The potential mechanism of Tan I was uncovered by an integrative approach combining RNA profiling and hydrogen nuclear magnetic resonance-based metabolic analysis, molecular docking and Western blot. Results: Tan I significantly inhibited the growth and colony formation of HeLa and SiHa cells. It induced apoptosis and cell cycle S phase arrest at low (12.5-25 mu M) but not high (50 mu M) concentrations. It also altered the HeLa cell ultrastructure, decreased the membrane potential and increased the total mitochondrial content. Further, Tan I induced autophagic flux and the colocalization of mitochondria with lysosomes, led to decreased adhesion, invasion, and migration of cervical cancer cells. Transcriptomic analysis revealed that Tan I altered the RNA profile and signal processing in HeLa cells. Tan I significantly impacted central carbon metabolism in cancer and mitophagy-animal processes. A global metabolic analysis identified 25 metabolites affected by Tan I treatment in HeLa cells. Changes in the metabolic profile indicated that Tan I affected such processes as protein digestion and absorption, central carbon metabolism in cancer, and aminoacyl-tRNA biosynthesis in cervical cancer cells. Furthermore, Tan I significantly induced the expression of mitophagy-related proteins BNIP3, NIX and Optineurin and the conversion from LC3-I to LC3-II, inhibited the NDP52 and P62 level in a concentration-dependent manner. While CQ further increased the conversion of LC3-I to LC3-II and the expression of P62. Moreover, Tan I interacted with BNIP3 and NIX through hydrogen bond. Tan I induce mitophagy could be prevented by BNIP3 and NIX siRNA transfection. Conclusion: Tan I induced the BNIP3/NIX-mediated mitophagy, and reprogrammed the mitochondrial metabolism in cervical cancer cells, thus inhibiting metastasis.

Automated summary

The study found that Tanshinone I can inhibit the growth and migration of cervical cancer cells, induce apoptosis and cell cycle arrest. It also induces autophagy and mitophagy in cervical cancer cells by affecting mitochondrial function and metabolism, thus inhibiting metastasis.