Cal 27 cells

CAL-27 cells (Procell Life Science & Technology Co. Ltd., Wuhan, China) were incubated in DMEM medium (GIBCO, Invitrogen Corporation, New York, NY, USA) containing 10% fetal bovine serum (Hyclone, Logan, UT, USA), 100 U/mL penicillin and 100 mg/mL streptomycin at 37 °C, 5% CO₂, 95% relative humidity (Thermo Forma 3111, Waltham, MA, USA) and cells in logarithmic growth phase were taken for the experiment.
CAL-27 cells were inoculated in a 96-well plate and incubated OF/PVP/PVA hydrogels with different concentrations of osmanthus extract for 24 h, MTT assay was used to detect the OD value of each well and calculate the cell viability (Microplate reader, Bio-Tek, VT, USA).

The CAL-27 cells used in this study were obtained from Procell Life Science & Technology Co., Ltd. (Wuhan, China); the SCC-9 cells were purchased from Shanghai EK-Bioscience Biotechnology Co., Ltd. (Shanghai, China). Both cell lines were STR-authenticated and tested for mycoplasma contamination. CAL-27 cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM; VivaCell, Shanghai, China) supplemented with 10% foetal bovine serum (Gibco, Grand Island, NY, USA) and 1% antibiotics (Gibco). SCC-9 cells were cultured in DMEM/Nutrient Mixture F-12 (DMEM/F12) supplemented with 10% foetal bovine serum, 1% antibiotics, and 400 ng/mL hydrocortisone (Complete Growth Medium from Procell). Small interfering RNA (siRNAs) were transfected at a working concentration of 100 nM using Lipofectamine® RNAiMAX Reagent (Invitrogen, Carlsbad, CA, USA), according to the manufacturer’s instructions. Stable cell lines expressing shLEF1 or shKDM4A were generated by transfecting LV2-shLEF1 or LV2-shKDM4A into CAL-27 cells using the transfection reagent polybrene (Gene Pharma, Shanghai, China), followed by selection with 2 µg/ml puromycin (Sigma-Aldrich, St. Louis, MO, USA). The siRNA and small hairpin RNA (shRNA) sequences designed by Gene Pharma are listed in Table S1 of Supplementary Figures and Tables.