Dysregulation of mTOR, GADD45a, and CDKN1A in HepG2/C3A Spheroids Treated With Ursolic Acid

Phytochemicals are plant-derived compounds extensively studied for the discovery and development of new drugs. Ursolic acid (UA), a pentacyclic triterpenoid phytochemical extracted from the bark and leaves of plants in the Lamiaceae family, has been the focus of research due to its antiproliferative potential, which has not yet been evaluated in tumor spheroids. This study aimed to analyze the antiproliferative effects and mechanisms of action of UA in 3D cultures (spheroids) of HepG2/C3A cells (human hepatocarcinoma). The analyses in 3D culture included average spheroid volume, genotoxicity using the comet assay, and the influence on mRNA expression, based on the cytotoxicity of UA assessed by the resazurin assay in 2D culture. The data showed that after 24 h of treatment, UA exhibited cytotoxicity at concentrations of 100 and 150 μM, reduced spheroid growth, demonstrated genotoxicity, and induced an increase in MTOR gene expression (2.38×). At 72 h, there was an upregulation of GADD45A (8.8×) and a downregulation of CDKN1A (2×). It is concluded that UA exhibits antiproliferative actions, promoting changes in the expression of genes associated with cell cycle control and DNA damage. This study has contributed to understanding the mechanism of action of this phytochemical for its therapeutic potential.