miR-125b-5p, miR-155-3p, and miR-214-5p and Target E2F2 Gene in Oral Squamous Cell Carcinoma

Abstract

It is known that E2F2 (E2F transcription factor 2) plays an important role as controller in the cell cycle. This study aimed to analyse the expression of the E2F2 gene and E2F2 protein and demonstrate E2F2 target microRNAs (miRNAs) candidates (miR-125b-5p, miR-155-3p, and miR-214-5p) in oral squamous cell carcinoma tumour and margin samples. The study group consisted 50 patients. The E2F2 gene and miRNAs expression levels were assessed by qPCR, while the E2F2 protein was assessed by ELISA. When analysing the effect of miRNAs expression on E2F2 gene expression and E2F2 protein level, we observed no statistically significant correlations. miR-125b-5p was downregulated, while miR-155-3p, and miR-214-5p were upregulated in tumour samples compared to margin. We observed a difference between the miR-125b-5p expression level in smokers and non-smokers in margin samples. Furthermore, HPV-positive individuals had a significantly higher miR-125b-5p and miR-214-5p expression level compared to HPV-negative patients in tumour samples. The study result showed that the E2F2 gene is not the target for analysed miRNAs in OSCC. Moreover, miR-155-3p and miR-125b-5p could play roles in the pathogenesis of OSCC. A differential expression of the analysed miRNAs was observed in response to tobacco smoke and HPV status.

The Analysis of Selected miRNAs and Target MDM2 Gene Expression in Oral Squamous Cell Carcinoma

“…The characteristics of the study group were presented in the previous study [23]. The study group comprised 50 OSCC patients recruited at the Department of Otorhinolaryngology and Oncological Laryngology in Zabrze, Medical University of Silesia, in Katowice (Poland).…”

“…KNW/022/KB1/49/16 and no. KNW/002/KB1/49/II/16/17) [23]. The clinical data of the OSCC group are presented in Table 1.…”

“…The clinical data of the OSCC group are presented in Table 1. The methodology for the extraction was presented in previous studies [23,27]. All tissue samples were homogenized with the FastPrep ® -24 homogenizer (MP Biomedicals, Solon, CA, USA) with Lysing Matrix D ceramic beads (MP Biomedicals, Solon, CA, USA).…”

“…The RNA and miRNAs were extracted using the RNA isolation kit (catalogue number RIK 001, BioVendor, Brno, Czech Republic) to the standard instruction. The concentration and purity of the isolated RNA were determined using spectrophotometry in a NanoPhotometer Pearl UV/Vis Spectrophotometer (Implen, Munich, Germany) [23,27].…”

“…The methodology for the cDNA synthesis was presented in previous studies [23,27]. The obtained RNA (5 ng) was reverse-transcribed using the TaqMan ® Advanced miRNA cDNA Synthesis Kit (Applied Biosystems, Foster City, CA, USA) according to manufacturer's protocol.…”