Anti-Colorectal Cancer Activity of Solasonin from Solanum nigrum L. via Histone Deacetylases-Mediated p53 Acetylation Pathway

(1) Background: Solanum nigrum L. is a plant of the genus Solanum in the family Solanaceae and is commonly used to treat tumors. Solasonin (SS) is a steroidal alkaloid extracted from Solanum nigrum L. that has anti-colorectal cancer (CRC) activity. (2) Methods: Column chromatography, semi-preparative HPLC and cellular activity screening were used to isolate potential anti-CRC active compounds in Solanum nigrum L., and structure identification using (1)H-NMR and (13)C-NMR techniques. Expression levels of HDAC in CRC were mined in the UALCAN database. The in vitro effects of SS on SW620 cell line and its mechanism were examined via Western blot, EdU staining, flow cytometry and immunofluorescence. CRC xenograft model and IHC staining were mainly used to evaluate the role of SS in vivo. (3) Results: The results showed that SS was the most potent anti-CRC component in Solanum nigrum L., which induced apoptosis and cell cycle arrest in the SW620 cell line. HDAC was highly expressed in CRC. The treatment of SW620 cell line with SS resulted in a significant downregulation of HDAC, an increase in the level of P53 acetylation and a subsequent increase in the level of P21. The in vivo validation results showed that SS could effectively inhibit CRC growth, which was associated with the downregulation of HDAC. (4) Conclusions: SS treatment for CRC mainly works through the induction of apoptosis and cycle arrest, and its mechanism of action is mainly related to HDAC-induced P53 acetylation, and the HDAC/P53 signaling pathway may be a potential pathway for the treatment of CRC.