Ruangan Lidan decoction inhibits the growth and metastasis of liver cancer by downregulating miR-9-5p and upregulating PDK4

A growing number of studies have suggested that traditional Chinese medicine (TCM) plays an essential role in the development and occurrence of liver cancer. However, the function of Ruangan Lidan decoction (RLD) in liver cancer are not yet adequately identified and manifested, which attracted our attention. The key genes related to liver cancer and RLD and the upstream miRNAs of PDK4 were obtained based on bioinformatics analysis, followed by verification of the targeting relationship between miR-9-5p and PDK4. Next, Huh7 cells were treated with RLD to detect cell proliferation, colony formation, migration, invasion, and apoptosis by multiple assays with gain- and loss-of-function experiments. Moreover, subcutaneous transplanted tumor model and lung metastasis model of liver cancer in nude mice were established to further verify the functional role of RLD in liver cancer growth and metastasis via miR-9-5p/PDK4 axis. Bioinformatics analysis found that PDK4 and miR-9-5p were related to liver cancer, and PDK4 may be a downstream regulator of RLD. miR-9-5p could target and inhibit PDK4. In vitro cell experiments demonstrated that RLD suppressed liver cancer cell proliferation, invasion and migration, and promoted apoptosis by inhibiting miR-9-5p expression and promoting PDK4 expression. In vivo animal experiments further confirmed that RLD inhibited liver cancer growth and metastasis via upregulation of miR-9-5p-dependent PDK4. RLD downregulated miR-9-5p and upregulated PDK4 to inhibit the proliferation, migration, invasion, and induce apoptosis, thereby suppressing the growth and metastasis of liver cancer, highlighting a potential novel target for treatment of liver cancer.