4-Terpineol exhibits potent in vitro and in vivo anticancer effects in Hep-G2 hepatocellular carcinoma cells by suppressing cell migration and inducing apoptosis and sub-G1 cell cycle arrest.

PURPOSE The main purpose of this study was to demonstrate the anticancer effects of 4-terpineol against Hep-G2 hepatocellular carcinoma (HCC) cells by evaluating its effect on apoptosis induction, cell migration, DNA fragmentation and cell cycle phase distribution. METHODS MTT assay was used to evaluate the cytotoxic effect of 4-terpineol on Hep-G2 cells, while fluorescence microscopy and flow cytometry were used to study apoptosis induction. Wound healing assay was used to study the effects of 4-terpineol on cell migration, while gel electrophoresis was performed to evaluate the effects on DNA fragmentation. Flow cytometry using propidium iodide (PI) as a probe was used to evaluate the effects on cell cycle arrest. Cells treated with dimethylsulfoxide (DMSO) only served as controls. BALB/c nude mice weighing about 35 g each were used for in vivo studies using 10 and 20 mg/kg of 4-terpineol dose. RESULTS 4-terpineol induced dose-dependent cytotoxicity in Hep-G2 hepatocellular carcinoma cells. Gel electrophoresis indicated that DNA fragmentation was associated with increasing dose of 4-terpineol. It was also observed that a wound scratch in the vehicle-treated control cells was practically entirely closed after 48 hrs of incubation. However, treatment with 0, 25, 50 and 100 μM dose of 4-terpineol resulted in inhibition of wound healing in a dose-dependent manner. The percentage of apoptotic cells increased from 2.5% in the control cells to 10.3, 64.6 and 78.9% in cells treated with 25, 50 and 100 μM of 4-terpineol respectively. 4-terpineol-treated cells exhibited increased percentage of cells in sub-G1 phase of the cell cycle. The in vivo mouse results indicated that 10 and 20 mg/kg of 4-terpineol decreased the tumor weight and tumor volume in a dose-dependent manner. CONCLUSION The results of this study showed that 4-terpineol exhibits anticancer effects in Hep-G2 cells by inducing apoptosis, DNA fragmentation, inhibition of cell migration and sub-G1 cell cycle arrest.