miRNA-329-3p suppresses proliferation and metastasis of endometrial carcinoma through downregulating E2F1

Existing evidences have revealed the crucial roles of E2 promoter binding factor-1 (E2F1) during the tumorigenesis and progression process of multiple human tumors. However, the expression patterns, biological functions, as well as the underlying molecular mechanism of E2F1 in endometrial carcinoma yet remain largely unclear. The expression patterns and clinical prognostic value of E2F1 in endometrial carcinoma were evaluated using bioinformatics methods. Protein and mRNA, miRNA expression levels in tissues and cells were measured using immunohistochemistry, western blotting, and qRT-PCR assays. Cell viability and cell cycle distribution were examined using CCK-8 assay and flow cytometry, respectively. Scratch healing assay and Transwell assay were applied to measure cell migration and invasion ability. Bioinformatic analysis and luciferase reporter assays were conducted to confirm the targeting relationship between E2F1 and miR-329-3p. Moreover, a series of in vitro and in vivo functional experiments were employed to evaluate the effect of the miR-329-3p/E2F1 axis on cell growth and metastasis. Clinically, E2F1 was aberrantly expressed in endometrial carcinoma tissues and was correlated with advanced FIGO stage, histological type, p53 mutation, poor survival, and degree of tumor cell differentiation. ROC curves analysis also reveals that E2F1 has a high AUC value (up to 0.952, 95% CI: 0.915-0.988), indicating the promising diagnostic value of E2F1 level in endometrial carcinoma. In addition, in vitro gain and loss-of-functional experiments verified that high E2F1 can promote cell proliferation, cell cycle, migration, invasion, and EMT process. In-depth mechanism studies revealed that E2F1 was a downstream target gene of miR-329-3p, and miR-329-3p overexpression could effectively abrogate its promotion of cell malignant biological behavior. Collectively, our findings suggested that the miR-329-3p/E2F1 axis plays a crucial role in the progression of endometrial carcinoma, indicating that E2F1 can be considered a promising diagnostic and prognostic biomarker for endometrial carcinoma patients.