Circulating and Endometrial Profiles of miR-145, miR-155-5p, miR-224, MPP-5, and PECAM-1 Expression in Patients with Repeated Implantation Failure: A Case Control Study

OBJECTIVE

An association between microRNAs (miRNAs) and adhesion proteins expression with repeated implantation failure (RIF) has been recently reported; however, these findings are controversial. This study aims to evaluate the endometrial and circulating expressions of miR-145, miR-155-5p, and miR-224 in addition to the endometrial expressions of membrane protein palmitoylated-5 (MPP-5) and endothelial cell adhesion molecule-1 (PECAM-1) in patients with RIF compared to control subjects.

MATERIALS AND METHODS

This case-control study was carried out between June 2021-July 2022. Subjects included 17 patients with RIF and 17 control subjects, who had previous spontaneous term pregnancy with a live birth, who referred to the Medical Centre of Arash Hospital, Tehran, Iran. Endometrial tissue samples were obtained via hysteroscopy and Pipelle catheter in the RIF and control subjects, respectively. Plasma samples were collected after ovulation in all subjects. The expression levels of MPP5, PECAM-1, miR-224, miR-145, and miR-155-5p were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). The student's t test, chi-square, Mann-Whitney U, and analysis of covariance (ANCOVA) were used for data analyses.

RESULTS

RIF patients had less endometrial miR-155-5p expression, and higher endometrial and circulating expressions of miR-145 and miR-224 compared to control subjects. Endometrial PECAM-1 and MPP5 expression significantly decreased in patients with RIF compared to the control group. There was a positive correlation between circulating miR-224 and endometrial miR-155-5p, and between circulating miR-155-5p and endometrial PECAM-1 expression levels in patients with RIF.

CONCLUSION

The present study suggests that circulating miR-224, endometrial miR-145, and PECAM-1 can be reliable, novel biomarkers for diagnosis of RIF.

MicroRNA-224 inhibits proliferation and migration of breast cancer cells by down-regulating Fizzled 5 expression

The Wnt/β-catenin signaling is crucial for the proliferation and migration of breast cancer cells. However, the expression of microRNA-224 (miR-224) in the different types of breast cancers and its role in the Wnt/β-catenin signaling and the proliferation and migration of breast cancer cells are poorly understood. In this study, the levels of miR-224 in different types of breast cancer tissues and cell lines were examined by quantitative RT-PCR and the potential targets of miR-224 in the Wnt/β-catenin signaling were investigated. The effects of altered miR-224 expression on the frequency of CD44⁺CD24⁻ cancer stem-like cells (CSC), proliferation and migration of MCF-7 and MDA-MB-231 cells were examined by flow cytometry, MTT and transwell migration. We found that the levels of miR-224 expression in different types of breast cancer tissues and cell lines were associated inversely with aggressiveness of breast cancers. Enhanced miR-224 expression significantly reduced the fizzled 5-regulated luciferase activity in 293T cells, fizzled 5 expression in MCF-7 and MDA-MB-231 cells, the β-dependent luciferase activity in MCF-7 cells, and the nuclear translocation of β-catenin in MDA-MB-231 cells. miR-224 inhibition significantly increased the percentages of CSC in MCF-7 cells and enhanced proliferation and migration of MCF-7 cells. Enhanced miR-224 expression inhibited proliferation and migration of MDA-MB-231 cells, and the growth of implanted breast cancers in vivo. Induction of frizzled 5 over-expression mitigated the miR-224-mediated inhibition of breast cancer cell proliferation. Collectively, these data indicated that miR-224 down-regulated the Wnt/β-catenin signaling possibly by binding to frizzled 5 and inhibited proliferation and migration of breast cancer cells.

MiR-224 expression increases radiation sensitivity of glioblastoma cells

Glioblastoma (GBM) is the most common and highly aggressive primary malignant brain tumor. The intrinsic resistance of this brain tumor limits the efficacy of administered treatment like radiation therapy. In the present study, effect of miR-224 expression on growth characteristics of established GBM cell lines was analyzed. MiR-224 expression in the cell lines as well as in primary GBM tumor tissues was found to be low. Exogenous transient expression of miR-224 using either synthetic mimics or stable inducible expression using doxycycline inducible lentiviral vector carrying miR-224 gene, was found to bring about 30-55% reduction in clonogenic potential of U87 MG cells. MiR-224 expression reduced clonogenic potential of U87 MG cells by 85-90% on irradiation at a dose of 6Gy, a dose that brought about 50% reduction in clonogenic potential in the absence of miR-224 expression. MiR-224 expression in glioblastoma cells resulted in 55-65% reduction in the expression levels of API5 gene, a known target of miR-224. Further, siRNA mediated down-regulation of API5 was also found to have radiation sensitizing effect on glioblastoma cell lines. Analysis of the Cancer Genome Atlas data showed lower miR-224 expression levels in male GBM patients to correlate with poorer survival. Higher expression levels of miR-224 target API5 also showed significant correlation with poorer survival of GBM patients. Up-regulation of miR-224 or down-regulation of its target API5 in combination with radiation therapy, therefore appear as promising options for the treatment of glioblastoma, which is refractory to the existing treatment strategies.

Regulatory feedback loop between T3 and microRNAs in renal cancer

microRNAs, short non-coding RNAs, influence key physiological processes, including hormonal regulation, by affecting the expression of genes. In this study we hypothesised that the expression of microRNAs targeting thyroid hormone pathway genes may be in turn regulated by thyroid hormone signalling. It is known that the expression of DIO1, a gene contributing to triiodothyronine (T3) signalling, is regulated by miR-224. Thus, we analysed mutual regulation between triiodothyronine pathway and miR-224/miR-452/GABRE cluster. Firstly, we found that miR-452 directly regulates the expression of thyroid hormone receptor TRβ1 in renal cancer cells. In turn, the expression of miR-224/452/GABRE cluster and other microRNAs targeting TRβ1 was influenced by T3 treatment and/or TR silencing. miR-452 expression correlated with intracellular T3 concentrations in renal tumours. In conclusion, we propose a new mechanism of feedback regulation, by which in renal cancer microRNAs regulate the expression of T3 pathway genes, while T3 in turn regulates expression of microRNAs.

MiR-224 impairs adipocyte early differentiation and regulates fatty acid metabolism

MicroRNAs (miRNAs) are small ~22 nucleotide regulatory RNAs that regulate the stability and translation of cognate messenger RNAs (mRNAs). MicroRNAs participate in the regulation of adipogenesis and identification of the full repertoire of MicroRNAs expressed in adipose tissue is likely to improve our understanding of adipose tissue growth and development significantly. In the present study, it is found that miR-224-5p abundance decreases first and then increases during adipogenesis of 3T3-L1 cells. And early growth response 2 (EGR2) and Acyl-CoA synthetase long-chain family member 4 (ACSL4) are direct targets of miR-224-5p. Further studies in mouse 3T3-L1 cell-line shows that miR-224-5p is a novel negative regulator of adipocyte differentiation through post-transcriptional regulation of early growth response 2 during early adipogenesis. Furthermore, miR-224-5p could regulate fatty acid metabolism through Acyl-CoA synthetase long-chain family member 4 at terminal differentiation. It indicates that miR-224 plays different roles on different stages of adipogenesis.