Aloin promotes oral squamous cell carcinoma cell apoptosis and autophagy through Akt/mTOR pathway

Aloin, a natural product, has demonstrated anticancer activity in a variety of cancers, but its role in oral squamous cell carcinoma (OSCC) has not been reported. In this study, we aimed to investigate the effects of Aloin on the biological functions of OSCC cells. Additionally, we evaluated the classical Akt/mTOR signal transduction pathway. CAL-27 OSCC cells were treated with Aloin for in vitro experiments. 5-bromo-2’-deoxyuridine (BrdU) and colony formation assays were applied to evaluate cell proliferation potential. Wound scratch and Transwell assays detected cell migration and invasion, respectively. Flow cytometry detected apoptosis. Autophagy was assessed by p62, Beclin-1, light chain 3 (LC3)-I and LC3-II protein expressions through Western blot test. Akt/mTOR signal pathway-related protein levels were also detected by Western blot test. Here, compared with the control group, Aloin treatment memorably reduced the number of BrdU-positive cells and colonies, and undermined the ability of cell migration and invasion. Moreover, Aloin promoted apoptosis and autophagy. Western blot test proved that the protein expression of p62 was down-regulated, while Beclin-1 and LC3-I/LC3-II protein expressions were up-regulated. Further investigations revealed that Aloin inhibited p-Akt and p-mTOR, suggesting that Aloin could block the activation of AKT/mTOR pathway. Our findings demonstrated that Aloin could inhibit the activation of the AKT/mTOR pathway to induce autophagic cell death, which could provide a novel vision for OSCC treatment.