Isoliquiritigenin Inhibits Proliferation and Induces Apoptosis in Tongue Squamous Cell Carcinoma by Modulating miR-21/FOXG1 Pathway

Isoliquiritigenin is a flavonoid commonly found in liquorice and has been identified as a potent anti-tumor agent. The aim of this study was to investigate whether isoliquiritigenin regulates the proliferation and apoptosis of tongue squamous cell carcinoma cells by regulating forkhead box G1 expression via miR-21. MTT assay and flow cytometry were used to analyze cell proliferation and apoptosis, respectively. Quantitative real time polymerase chain reaction and western blotting were used to detect mRNA and protein expression levels, respectively. The relationship between miR-21 and forkhead box G1 was detected by dual luciferase assay. Isoliquiritigenin inhibited proliferation and induced apoptosis of tongue squamous cell carcinoma cells, and decreased miR-21 levels and promoted forkhead box G1 expression. Forkhead box G1 was then identified as a target of miR-21 and ISL could promote forkhead box G1 expression by inhibiting miR-21. Further analysis suggested that upregulation of miR-21 improved proliferation and suppressed apoptosis of tongue squamous cell carcinoma cells by inhibiting forkhead box G1 expression. Finally, our results revealed that isoliquiritigenin inhibited proliferation and induced apoptosis of tongue squamous cell carcinoma cells by regulating miR-21. Isoliquiritigenin might act as a novel therapeutic treatment for tongue squamous cell carcinoma cells through up-regulation of forkhead box G1 expression via inhibiting miR-21expression.