Fatty Acid–Binding Protein 4 (FABP4) Suppresses Proliferation and Migration of Endometrial Cancer Cells via PI3K/Akt Pathway

PURPOSE: Endometrial cancer (EC) is the sixth most common cancer in women and its incidence and mortality have been rising over the last decades. The latest research indicates that FABP4 plays a significant role in multiple types of cancer. But few studies were focused on EC. The aim of this article is to investigate whether FABP4 can suppress tumor growth and metastasis of EC via PI3K/Akt pathway to provide a novel therapeutic target for the treatment of EC. MATERIALS AND METHODS: FABP4 mRNA levels of EC were analysed through The Cancer Genome Atlas database (TCGA), and expression of FABP4 in EC cancer tissues was determined by immunohistochemistry (IHC) assays. Stable overexpressing cell lines were established using lentivirus infection to analyze the biological function of FABP4 in vitro. CCK8 assay and colony formation assay were performed to assess cell proliferation ability. Wound healing assay and transwell were performed to analyse migration and invasion of cells. The subcutaneous xenograft mouse model was used to evaluate tumor growth in vivo. Additionally, all protein levels were detected by Western blotting assay. RESULTS: We found that the expression of the FABP4 mRNA was decreased in tumor samples compared to normal tissue according to TCGA database analysis. Subsequent experimental mRNA and protein expression analysis confirmed that FABP4 expression was lower in EC tissue than normal endometrial tissue. In addition, we found overexpression of FABP4 inhibited the proliferation, migration and invasion in vitro and suppressed tumor growth in vivo. Further functional and mechanistic analysis of FABP4 demonstrated that its function is mediated by restraining the phosphorylation of PI3K/Akt signaling pathway. CONCLUSION: Our studies shed light for the first time about the functional role of FABP4 in EC and provide a novel biomarker for EC as well as a therapeutic target for the therapy of EC.