Actein Antagonizes Oral Squamous Cell Carcinoma Proliferation Through Activating Foxo1

Background: Oral squamous cell carcinoma (OSCC) is among the most prevalent head and neck malignancies globally, and it is associated with high mortality rates. Actein is one of the primary active components extractable from the rhizomes of Cimicifuga foetida. This study aimed to evaluate the anti-OSCC effects of actein and evaluate the potential underlying mechanisms. Methods and Results: CCK-8 cell proliferation experiments demonstrated significant dose- and time-dependent anti-OSCC effects of actein, while actein had weak cytotoxic effects on normal oral cell lines. Flow cytometry for cell cycle evaluation revealed that actein could induce cell cycle arrest at the G1 phase among OSCC cell lines. In our Annexin V/PI double staining apoptosis analysis, actein induced significant apoptosis among OSCC cells, with upregulation of Bax and downregulation of Bcl-2. Our mechanistic study implicated the involvement of the Akt/FoxO1 pathway in the anti-OSCC effects of actein. Akt1 and Akt2 expression significantly decreased in association with the FoxO1 upregulation. Furthermore, Bim and p21 were significantly upregulated, while survivin expression was downregulated. Finally, actein treatment was associated with significant p-Akt downregulation and p-FoxO1 upregulation in OSCC cells, demonstrating the validated roles of Akt/FoxO1 in actein-mediated OSCC cell apoptosis and cell cycle arrest. FoxO1 knockdown significantly reversed the anti-OSCC effects of actein. Additionally, a xenograft model indicated that actein could inhibit OSCC cell growth in vivo. Conclusions: Our findings demonstrated that actein could be a strong anti-OSCC candidate. Further evaluations of its safety and effectiveness are necessary before it can be considered for clinical use.