ABSTRACT: Thermal ablation offers minimally invasive treatment options for hepatocellular carcinoma (HCC) therapy. However, local recurrence due to sublethal temperatures enhances tumor cell survival. This study aims to investigate the tumor-promoting effects of hyperthermia on HCC cells, the role of tanshinone IIA (Tan IIA) in mitigating these effects, and the underlying mechanisms involved. We observed that temperature at 44 °C increased the aggressiveness of HCC cells, and Tan IIA inhibited cell viability and cell invasion, and induced cell cycle arrest and apoptosis of heat-pretreated HCC cells. ALDH7A1 was identified as a target of Tan IIA, and its altered expression resulted in dysregulation of cell viability, invasion, apoptosis, ATP production, glycolysis, osmolyte levels, and reactive oxygen species (ROS). Under hyperosmotic conditions, ALDH7A1 knockdown sensitized heated Huh-7 cells, while its overexpression promoted cell survival and invasion, with corresponding changes in energy metabolism and enzymatic products. Tan IIA and the specific ALDH7A1 inhibitor, 4-diethylaminobenzaldehyde, demonstrated similar effects on gene expression patterns, glycolysis, osmotic regulation, and ROS levels in heated Huh-7 cells. Moreover, Tan IIA is able to direct interact with ALDH7A1 protein. In vitro, Tan IIA combined with hyperosmotic stress significantly inhibited cell invasion and induced apoptosis in heat-induced Huh-7 cells and ALDH7A1 overexpression partially reversed the effects of Tan IIA. In vivo, Tan IIA combined with hyperosmotic stress or glycolysis inhibitor yielded better therapeutic efficacy for HCC. In conclusion, Tan IIA sensitizes HCC cells to sublethal heat by targeting ALDH7A1, leading to disrupted glycolytic and osmolytic balance, subsequently hindering tumor cell survival and increasing apoptosis. These findings highlight a potentially novel strategy for preventing or treating recurrent HCC post-thermal ablation using Tan IIA with hyperosmotic reagents.
