Baicalin and valproic acid synergistically induce hepatocellular carcinoma cell apoptosis via ROS-mediated PTEN upregulation.

BACKGROUND AND

OBJECTIVE

The prognosis of liver cancer remains exceedingly poor. The therapeutic potential of baicalin (BAI), a natural bioactive compound, in treating liver cancer is significantly limited by its low bioavailability. The histone deacetylase inhibitor valproic acid (VPA) has been shown to enhance the efficacy of anticancer agents. This study aims to investigate the synergistic antitumor effects and underlying molecular mechanisms of BAI and VPA in combination against liver cancer.

METHODS

In vitro experiments were conducted using the CCK-8 assay, morphological observation, AO/EB dual fluorescence staining, wound healing assay, transwell migration assay, and western blot analysis. These findings were further validated in vivo using a mouse subcutaneous syngeneic tumor model.

RESULTS

VPA alone exhibited no significant cytotoxicity against HepG2 and SMMC-7721 liver cancer cells, whereas BAI inhibited the proliferation of both cell lines in a concentration-dependent manner. The combination of BAI and VPA exerted stronger inhibitory effects on cell migration and greater promotion of apoptosis compared to either agent alone, with efficacy comparable to that of the chemotherapeutic drug doxorubicin. At the mechanistic level, the combined administration of drugs promotes the intracellular accumulation of reactive oxygen species (ROS), upregulates the expression of the PTEN protein, and activates the ROS-PTEN-Bax signaling axis to modulate the expression of apoptosis-related proteins, thereby ultimately inducing apoptosis in hepatocellular carcinoma cells. The synergistic pro-apoptotic effect was significantly reversed upon scavenging ROS with N-acetylcysteine or by knocking down PTEN expression, confirming a positive feedback regulatory relationship between ROS and PTEN. Further in vivo experiments consistently demonstrated that the combination treatment of BAI and VPA inhibits the growth of syngeneic tumors in a concentration-dependent manner, with the low-concentration combination achieving an antitumor efficacy comparable to that of high-concentration BAI monotherapy.

CONCLUSION

BAI and VPA exert a synergistic anti-hepatocellular cancer effect through the ROS-PTEN-Bax pathway. This study provides a novel and effective therapeutic strategy for liver cancer and establishes a solid experimental foundation for repurposing VPA as a clinical adjuvant agent for BAI therapy.