MicroRNA-154-5p regulates the HPV16 E7-pRb pathway in Cervical Carcinogenesis by targeting CUL2

Abstract

Cervical cancer, induced by persistent HPV infection, has a high mortality rate. The E3 ubiquitin ligase Cullin 2 (CUL2) is critical for HPV16 E7-mediated degradation of retinoblastoma protein (pRb). Dysregulation of microRNAs (miRNAs) is induced during tumorigenesis; however, the association between miRNA networks and CUL2, specific to cervical cancer, remains unknown. Herein, we determined miRNA profiles in cervical cancer tissues using an Affymetrix miRNA array. We found that miR-154-5p was downregulated during cancer progression using real-time quantitative reverse transcription PCR in 130 biopsy specimens. Bioinformatics analysis and dual-luciferase reporter assays indicated that miR-154-5p directly targets the CUL2 3'UTR. To determine the functional consequences of modulating miR-154-5p and CUL2 levels, HPV16-positive cervical cancer cell line (SiHa) was transfected with miR-154-5p mimic, miR-154-5p inhibitor, or CUL2 siRNA. The proliferation, migration, and invasion of transfected cells were evaluated using CCK8 cell counting kit, wound-healing assay, and Transwell invasion assay. Increased miR-154-5p expression promoted significantly reduced SiHa cell proliferation, migration, and invasion, whereas the miR-154-5p inhibitor had the opposite effect. CUL2 silencing had similar effects to those of the miR-154-5p mimic. Consistent with the inverse correlation between miR-154-5p and CUL2 levels, CUL2 silencing also increased pRb expression. To our knowledge, this is the first study to demonstrate that miR-154-5p regulates pRb expression by targeting CUL2 3'UTR, thereby playing a tumor-suppressive role in HPV16 E7-induced cervical carcinogenesis.

miR-154 Influences HNSCC Development and Progression through Regulation of the Epithelial-to-Mesenchymal Transition Process and Could Be Used as a Potential Biomarker

“…Knockdown of miR-154-5p in HPV-16-positive SiHa cells caused increased cell proliferation, migration, along with the invasive ability, and its upregulation led to the reversed effect. They proved that miR-154-5p directly binds to the 3′UTR of CUL2, the core component of the E3 ubiquitin protein ligase complex, which, in turn, regulates the steady-state levels and stability of pRb [ 66 ]. It is worth mentioning that no reports of the direct role of miR-154-5p or -3p in HPV-positive HNSCC are available, and their diagnostic and biological role should be determined in the future.…”

The Dysregulation of MicroRNAs in the Development of Cervical Pre-Cancer—An Update

“…Three studies that employed a large sample size (n = 727, n = 230, and n = 130) [15,16,18] covered samples representing the whole cervical cancer progression from normal to LG-CIN, HG-CIN to cervical cancer. These studies aimed at screening out miRNAs which participate throughout the whole oncogenic processes.…”

The associations and roles of microRNA single-nucleotide polymorphisms in cervical cancer

“…These miRNAs with abnormal expression affect the expression of target genes in tumor-related signaling pathways and thus affect the regulation of signaling pathways and ultimately play a pivotal role in the occurrence and development of cervical cancer. For example, miRNAs may function as oncogenes or tumor suppressors to regulate the occurrence and development of cervical cancer through special signaling pathways, including the PI3K-AKT pathway 25 , Notch pathway 26 , E6-p53 pathway 27 , E7-pRb pathway 28 , Wnt/β-catenin pathway 29 , NF-κB pathway 30 , and Hedgehog pathway 31 .…”