Baicalein Inhibits the Growth of Transplanted Esophageal Cancer in Mice and the Effect on the Expression of PAK4

We studied the mechanism underlying the effect of baicalein on the growth of transplanted esophageal cancer in NOG mice and its effect on the expression of PAK4. For that purpose, we developed a new model of transplanted esophageal cancer (human esophageal cancer OE19 cells (10 7 cells/ml) were inoculated to NOG mice). Three experimental groups with transplanted esophageal cancer cells received baicalein in different doses (1, 1.5, and 2 mg/kg). In 32 days, the tumors were resected, and the expression of PAK4 and the level of activated PAK4 were assayed by reverse transcription PCR and Western blotting, respectively. The results showed a dose-depending anti-tumor effect of baicalein on the transplanted esophageal cancer in NOG mice: this effect of baicalein (determined by the size and weight of the tumor) increased with increasing the dose of the substance. Furthermore, the anti-tumor effect of baicalein was also confirmed by reduction of PAK4 expression. Thus, baicalein can inhibit tumor growth by inhibiting activation of PAK4. Therefore, our results showed that baicalein could inhibit the growth of esophageal cancer cells by inhibiting the activity of PAK4, which can be an important mechanism of its antitumor effect.