Abstract
Background: Cytochrome P450 2C8 (CYP2C8) gene is one of the members of the cytochrome P450 enzymes (CYPs) gene family. The aim of this study was to reveal the function of CYP2C8 in hepatocellular carcinoma (HCC) and its effect on the sorafenib resistance. Methods: Differential expression analysis in multiple HCC datasets all suggested that CYP2C8 expression was significantly decreased in HCC tissues, compared with para-carcinoma liver tissues. The expression level of CYP2C8 was subsequently compared between HCC tissues and para-carcinoma liver tissues of 70 patients form Guangxi, China, with the result consistent with the above. Survival analysis and ROC analysis indicated that CYP2C8 was equipped with satisfactory diagnostic and prognostic value in HCC. To examine the effect of CYP2C8 on the malignant phenotype of HCC cells, stable transcriptional cell lines with CYP2C8 over-expression were established, and then Cell Counting Kit-8 (CCK8) assay, colony formation assay, cell cycle assay, cell invasion assay and wound healing assay were performed. Results: The results of aforementioned assays suggested that CYP2C8 over-expression restricted the proliferation, clonality, migration, invasion and cell cycle of HCC cells but had no significant effect on cell apoptosis. The enrichment analysis in terms of sequencing data of HCC cell lines with stable CYP2C8 over-expression suggested that CYP2C8 might be related to PI3K/Akt/p27Kip1 axis. The inhibition of CYP2C8 over-expression on PI3K/Akt/p27Kip1 axis was subsequently demonstrated with Western blot assay. In the rescue experiment, it was observed that both P27 inhibitor and PI3K agonist counteracted the repressed malignant phenotype caused by CYP2C8 over-expression, which further demonstrated that CYP2C8 played a role in HCC cells via PI3K/Akt/p27Kip1 axis. Discussion: The results demonstrated that CYP2C8 enhances the anticancer activity of sorafenib in vitro assays and in tumor xenograft model, with Ki-67 down-regulation and PI3K/Akt/p27Kip1 axis inhibition. In conclusion, these findings hinted that CYP2C8 restricted malignant phenotype and sorafenib resistance in HCC via PI3K/Akt/p27kip1 axis.