Promotional effect of microRNA-194 on breast cancer cells via targeting F-box/WD repeat-containing protein 7

Abstract

Abstract. Breast cancer is the most common type of malignant cancer in females. An increasing number of studies have revealed that microRNAs (miR), which belong to a class of small non-coding RNAs, serve an important role in a number of human cancer subtypes. In the present study, the role of miR-194 in breast cancer cells and its underlying mechanisms were investigated. The results demonstrated that the serum levels of miR-194 were significantly higher in patients of the poorly differentiated and well-differentiated groups, compared with in healthy adults. Additionally, the serum level of miR-194 was significantly higher in the poorly differentiated group compared with in the well-differentiated group. In order to further investigate the role of miR-194 in breast cancer cells, the present study transfected two breast cancer cell lines, MCF-7 and MDA-MB-231, with an empty vector (control), miR-194 (overexpression), antagomiR-194 (inhibitor, functional knock down) or antagomiR-194 and miR-194. An MTT assay was performed in order to detect the proliferation of breast cancer cells in the various groups. The results revealed that the overexpression of miR-194 significantly accelerated cell proliferation, whereas the inhibition of miR-194 significantly decelerated the proliferation of MCF-7 and MDA-MB-231 cells. Furthermore, the expression levels of cyclin D and cyclin E were significantly upregulated in miR-194 overexpressing cells, and the expression levels of cyclin D and cyclin E were significantly downregulated in miR-194 inhibited cells, as compared with in control cells. No significant change was observed in the level of proliferation of cells co-transfected with miR-194 and antagomiR-194, compared with in the control cells. According to the hypothesis suggesting possible target genes of miR-194, the present study proposed that F-box/WD repeat-containing protein 7 (Fbxw-7) may be a direct target of miR-194, which was confirmed by a luciferase reporter assay. The present study suggested that miR-194 expression promoted the proliferation of breast cancer cells by targeting Fbxw-7, and may serve as a biomarker and a novel target for breast cancer therapy.

MALAT1 knockdown inhibits hypopharyngeal squamous cell carcinoma malignancy by targeting microRNA‑194

“…Additionally, miR-194 overexpression negatively regulates AKT serine/threonine kinase 2, which promotes gastric cancer cell proliferation and invasion (47). Following miR-194 suppression, the proliferation of breast cancer cell lines was significantly increased (48). The results of the present study were consistent with the aforementioned studies, suggesting that miR-194 was downregulated in HSCC and served as a tumor suppressor.…”

Connexin 43 maintains tissue polarity and regulates mitotic spindle orientation in the breast epithelium

“…For western blot analysis equal amounts of proteins were separated and immunoblotted with rabbit polyclonal antibodies against Cx43 (0.16 μg/ml; C6219 and 5 μg/ml; SAB4501175, Sigma-Aldrich; Ni et al, 2017), p-Akt (1:100; 9271, Cell Signaling Technology; Zhang et al, 2018), Akt (9272, 1:1000, Cell Signaling Technology; Geyer et al, 2018), β-catenin (0.04 μg/ml; sc7199, Santa Cruz Biotechnology; Nedvetsky et al, 2012); goat polyclonal antibody against ZO-2 (2 μg/ml, sc-8148, Santa Cruz Biotechnology; Talhouk et al, 2008); and monoclonal antibodies against Cx26 (0.5 μg/ml; 13-8100, Zymed Laboratories, San Francisco, CA), Cx43 (2 μg/ml; sc-271837, Santa Cruz Biotechnology; Lai et al, 2018) and ZO-1 (1 μg/ml; 33-9100, Life Technologies). Equal protein loading was verified by immunoblotting for lamin B (0.6 μg/ml; rabbit, Ab16048, Abcam; Jayaraman et al, 2017) and β-actin (1:1000; rabbit, A8227, Abcam; Chen et al, 2018). Protein levels were quantified using Scion NIH Image software (Scion Image, Scion Corporation, NIH) or ImageJ (http://imagej.nih.gov/ij/) and normalized to lamin B or β-actin expression levels.…”

Functional mechanisms of miR‐192 family in cancer

“…Moreover, the expression of cyclin D and E were increased following miR-194 overexpression in breast cancer cells. 99 Moreover, a lower level of miR-215 was detected in breast tumor tissues, which was observed to be closely correlated with higher tumor grade, human epidermal growth factor receptor 2 (HER2) positivity, and lymph node metastasis. Also, patients with low expression of miR-215 showed shorter 5-year disease-specific survival than the patients with high expression.…”

“…miR‐194 has a pivotal role in the oncogenic pathway of breast cancer progression, 98 and a high level of this miRNA leads to cell proliferation induction through targeting F‐box and WD repeat domain containing 7 (FBXW7). Moreover, the expression of cyclin D and E were increased following miR‐194 overexpression in breast cancer cells 99 …”