miR-326 inhibits the cell proliferation and cancer stem cell-like property of cervical cancer in vitro and oncogenesis in vivo via targeting TCF4

BACKGROUND: Cervical cancer ranks as one of the most prevalent female malignancies globally, and its treatment with new targets has been the focus of current research. The present study set out to investigate the function of microRNA-326 (miR-326) in vitro and in vivo and to verify the direct targeting of transcription factor 4 (TCF4) by miR-326. METHODS: The detection of messenger RNA (mRNA) expressing miR-326 and TCF4 in cervical cancer cell lines and tumor samples was conducted using quantitative real-time polymerase chain (qRT-PCR). A dual-luciferase reporter assay was carried out to detect the target relationship of miR-326 with TCF4. A Cell Counting Kit-8 (CCK-8) assay was employed to detect the effect of miR-326 on CasKi cell viability. Flow cytometry and western blotting were employed to examine the effects of miR-326 on cancer stem cell (CSC)-like property. Tumor weight was measured in orthotopic xenograft mouse models. Immunohistochemistry was employed to analyze the protein expression levels of Ki-67, proliferating cell nuclear antigen (PCNA), CD44, and SRY-box 4 (SOX4). RESULT: Downregulation of the mRNA expression levels of miR-326 was observed in cervical cancer cell lines and tumor tissue, while the levels of TCF4 were upregulated. The dual-luciferase reporter assay revealed binding of miR-326 to the three prime untranslated region (3'-UTR) of TCF4. In vitro assays demonstrated that miR-326 inhibited CasKi cell proliferation through regulating TCF4. miR-326 also suppressed the CSC-like property of CasKi cells by targeting TCF4. Furthermore, the protein expression levels of cyclin D1, β-catenin, and c-Myc were decreased when miR-326 was added to TCF4-transfected cells. In vivo assays demonstrated that miR-326 inhibited tumor weight, growth, and the protein expression levels of Ki-67, PCNA, CD44, SOX4, and β-catenin. CONCLUSIONS: miR-326 acted in a tumor-suppressive manner through its regulation of TCF4, and has potential as a biomarker or therapeutic target for cervical cancer.