Effects and mechanisms of Erianin on proliferation and apoptosis in oral squamous cell carcinoma cells

Objective To investigate the effects of Erianin on cell proliferation and apoptosis in human oral squamous cell carcinoma (OSCC) cells, providing a research foundation for the clinical treatment of OSCC. Methods Erianin was applied to OSCC cells (CAL27 and SCC9) at concentrations of 0, 2.5, 5, and 10 μmol/L. The inhibitory effect of Erianin on OSCC cell proliferation was evaluated using CCK-8 and soft agar colony formation assays. Western blotting (WB) was employed to analyze the expression levels of anti-apoptotic proteins B-cell lymphoma-extra large (Bcl-xL), B-cell lymphoma-2 (Bcl-2), myeloid cell leukemia-1 (Mcl-1), and apoptotic protein cleaved-Caspase 3 (c-Caspase 3) in OSCC cells. Caspase 3 activity was further assessed using a caspase 3 activity detection kit to examine the pro-apoptotic effect of Erianin in OSCC cells. Mcl-1 overexpression was induced in CAL27 cells via plasmid transfection, and the influence of Mcl-1 on the effects of Erianin in CAL27 cells was analyzed by WB and caspase 3 activity measurement. All animal experiments were approved by the Ethics Committee of Hunan Cancer Hospital. A CAL27 xenograft mouse model was established and randomly divided into two groups (n = 5): the treatment group received intraperitoneal injection of Erianin (25 mg/kg), while the control group was injected with phosphate-buffered saline (PBS) as the vehicle. Immunohistochemistry (IHC) was used to detect the expression levels of Ki67 and Mcl-1 in the tumor tissues. Results Erianin inhibited the proliferation of CAL27 and SCC9 cells in a dose-dependent manner and downregulated the protein expression of Mcl-1, with minimal effects on Bcl-2 and Bcl-xL. Furthermore, Erianin induced apoptosis in OSCC cells, as evidenced by increased expression of c-Caspase 3 and enhanced caspase 3 activity (P<0.001). Overexpression of Mcl-1 inhibited the Erianin-induced increase in c-Caspase 3 protein levels and caspase 3 activity. In vivo results were consistent with the in vitro findings. After Erianin treatment, CAL27 cell growth in nude mice was suppressed (P<0.001), and the expression levels of the proliferation marker Ki67 and the anti-apoptotic protein Mcl-1 in the tumor tissues were downregulated (P<0.001). Conclusion Erianin exhibits potent anti-tumor effects, effectively inhibiting the proliferation of OSCC cells and inducing apoptosis. The underlying mechanism may involve the downregulation of the pro-survival protein Mcl-1.