Cepharanthine Inhibits Doxorubicin-Induced Cellular Senescence by Activating Autophagy via the mTOR Signaling Pathway

Background: Doxorubicin (Dox) is a clinical first-line broad-spectrum anticancer agent. A dose-dependent cardiotoxic and myelosuppressive response limits the clinical use of Dox. Recent research indicates that Dox-induced cardiotoxicity is associated with senescent cell accumulation and that antiaging therapy can alleviate aging-related disorders. Cepharanthine (Cep) is commonly used to treat various acute and chronic illnesses, including leukopenia, snakebites, dry mouth, and hair loss. Whether Cep alleviates Dox-induced senescence is unknown. Methods: The expression of genes and proteins associated with aging was examined using NIH3T3 cell lines. The experiments were divided into a control group, a Dox group, and a Cep group on different days. NIH3T3 senescent cells were detected by senescence-β-galactosidase (SA-β-Gal) staining, and Western blotting was used to detect the protein levels of p16, p53, AMP-activated protein kinase (AMPK), mammalian target of the rapamycin (mTOR), p62, and Light Chain 3 (LC3). Fluorescence was used to detect the expression of monomeric red fluorescence protein-green fluorescence protein-Light Chain 3 (mRFP-GFP-LC3) and LC3 puncta in NIH3T3 cells. Real-time quantitative reverse transcription polymerase chain reaction (RT‒qPCR) was used to test the expression of senescence-associated secretory phenotypes (SASP: Interleukin 6 (IL-6), Interleukin 1 beta (IL-1β), and Interleukin 8 (IL-8)). Cell Counting Kit-8 (CCK-8) was used to assess NIH3T3 cell viability. Results: Here, we reported that Cep reversed the Dox-induced increase in the proportion of SA-β-Gal-positive cells and the high expression of aging-related proteins (p53, p < 0.05; p16, p < 0.05) and aging-related genes (IL-6, p < 0.05; IL-1β, p < 0.05; IL-8, p < 0.05) on the 3rd day. Mechanistically, Cep reduced the increase in the levels of phospho-mTOR (p < 0.05) on Days 1 and 3 and p62 protein (p < 0.05) caused by Dox on Day 1 and reversed the decline in LC3II/LC3I levels (p < 0.05) caused by Dox on Day 3, which is associated with the regulation of senescence. Additionally, the viability of NIH3T3 cells was significantly increased in the concentration range of 0.5–5 μM Cep (p < 0.05). Conclusions: We first found that Cep could suppress SA-β-Gal activity (p < 0.05) and the development of SASP. Additionally, in Cep-treated cells, Cep could restore autophagy dysfunction and suppress the mTOR signaling pathway. This research provides a new view on the mechanics of aging and autophagy and aids in developing novel antiaging drugs.