Purpose: Colorectal carcinoma (CRC) ranks third in incidence but second in mortality worldwide, ascertaining the pathogenesis of CRC is crucial for its treatment. Accumulating studies have shown that E2F1 is a key regulator in CRC progression, which regulates the transcription of genes engaged in DNA replication, mitosis and survival of cancer patients, however, the mechanism of these processes is not fully elucidated.
Methods: Here, we determined E2F1 expression in clinical CRC specimens by TCGA database analysis, Microarray immunohistochemical technique and Western blot, respectively. The expression of E2F1 was elevated in CRC tumor tissues, and the patients' total survival time was associated with the level of E2F1. Then the prediction software and meta-analysis were used to predict the miRNAs targeting E2F1. RT-qPCR, TCGA analysis and in situ hybridization experiments were utilized to determine the decreased miR-326 expression in CRC tumor tissues. Luciferase and Western blot assays determined that miR-326 directly targeted E2F1 in CRC cells. Next, CCK8, flow cytometry, Transwell and wound healing assays were used to determine the biological function of miR-326-E2F1 axis in vitro.
Results: miR-326 overexpression significantly inhibited the viability, invasion and migration and promoted the apoptosis of CRC cells, but overexpression of both E2F1 and miR-326 in turn increased cell viability, invasion and migration and decreased cell apoptosis.
Conclusions: This study demonstrates the significant roles of miR-326-E2F1 in CRC progression and may represent a potential target for CRC therapy.