To investigate the effects of andrographolide on microRNA (miR) -218-5p/RY box transcription factor 5 (SOX5) on the proliferation, invasion and epithelial mesenchymal transformation (EMT) of oral squamous cell carcinoma cells.

CAL-27 cells were divided into the following groups: blank group (conventional culture), andrographolide group (treated with 15 μmol·L^-1 andrographolide), andrographolide + inhibitor NC group (treated with 15 μmol·L^-1 andrographolide and transfected with inhibitor NC), andrographolide + miR-218-5p inhibitor group (treated with 15 μmol·L^-1 andrographolide and transfected with miR-218-5p inhibitor), andrographolide + miR-218-5p inhibitor + si-NC group (treated with 15 μmol·L^-1 andrographolide and co-transfected with miR-218-5p inhibitor and si-NC), and andrographolide + miR-218-5p inhibitor + si-SOX5 group (treated with 15 μmol·L^-1 andrographolide and co-transfected with miR-218-5p inhibitor and si-SOX5). The relative expression levels of miR-218-5p and SOX5 mRNA were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR), cell proliferation ability was measured using the 5-ethynyl-2′-deoxyuridine (EdU) assay, cell invasion ability was assessed by Transwell assay, and the relative expression levels of EMT-related proteins were determined by Western blotting.

After different treatment periods, the relative expression levels of miR-218-5p in blank group, andrographolide group, andrographolide + inhibitor NC group and andrographolide + miR-218-5p inhibitor group were 1.00±0.11, 2.76±0.48, 2.69±0.50 and 1.19±0.17, respectively; the relative expression levels of SOX5 mRNA were 1.00±0.09, 0.36±0.07, 0.35±0.05 and 0.93±0.18, respectively. Compared with the blank group, the andrographolide group showed statistically significantly upregulated miR-218-5p relative expression levels and statistically significantly reduced SOX5 mRNA relative expression levels (all P<0.05). The proliferation rates in blank group, andrographolide group, andrographolide + inhibitor NC group, andrographolide + miR-218-5p inhibitor group, andrographolide + miR-218-5p inhibitor + si-NC group and andrographolide + miR-218-5p inhibitor + si-SOX5 group were (62.76±8.14)%, (23.58±2.87)%, (25.12±3.64)%, (51.29±9.12)%, (50.76±8.29)% and (34.18±6.83)%, respectively; the number of invasive cells were (154.23±17.24), (67.13±9.37), (72.81±11.28), (125.36±18.74), (118.15±19.80) and (80.44±12.13), respectively; the relative expression levels of E-cadherin were 1.00±0.12, 2.62±0.43, 2.56±0.47, 1.47±0.27, 1.51±0.23 and 2.24±0.43, respectively; the relative expression levels of N-cadherin were 1.00±0.11, 0.41±0.08, 0.39±0.06, 0.83±0.17, 0.86±0.15 and 0.51±0.10, respectively; the relative expression levels of Vimentin were 1.00±0.08, 0.49±0.07, 0.46±0.09, 0.85±0.16, 0.88±0.17 and 0.55±0.11, respectively. Compared with blank group, andrographolide group showed statistically significantly decreased proliferation rate, number of invasive cells and relative expression levels of N-cadherin and Vimentin, while demonstrating statistically significantly increased relative expression levels of E-cadherin (all P<0.05).

Andrographolide inhibits the proliferation, invasion, and EMT in oral squamous cell carcinoma, potentially through upregulating miR-218-5p and subsequently targeting the suppression of SOX5 expression.