the egyptian journal of histology | 2019
The Regulatory Role of Syndecan-1 on Human MiR-222-3p Expression in Breast Cancer Cell Lines
Abstract
Introduction: MicroRNAs (miRNAs), small non-coding endogenous RNA molecules whose length ranging from 18-25 nucleotides, are implicated in regulating many physiological and pathological processes, including cell proliferation and apoptosis, adhesion, migration, invasiveness, epithelial-to-mesenchymal transition and the cancer stem cell properties. These molecules regulate gene expression at the posttranscriptional level by inducing mRNA degradation or translational repression. It was reported in previous work that miR-222-3p expression and Syndecan-1 (SDC-1) silencing regulate the aggressiveness of primary breast cancer and its metastasis. SDC-1, a cell surface heparan sulphate proteoglycan acting as a co-receptor for many growth factor receptors, is known to regulate the expression of many miRNAs. However, its impact on miR-222-3p expression in breast cancer is still unclear. Aim of the Work: To investigate the effect of SDC-1 silencing on the expression of hsa-miR-222-3p in the human breast cancer cell lines. Materials and Methods: We used the human breast cancer cell lines MCF-7 (low invasive) and MDA-MB-231 (highly invasive), which were transfected with 20 nM control and SDC-1 siRNA.hsa-mir-222-3p expression was analyzed by quantitative PCR (qPCR) in control and SDC-1-silenced cells 48h post transfection. Moreover, the expression of β-catenin protein72h post SDC1 knockdown was assessed by Western blotting. Results: No significant change was observed for the expression levels of hsa-miR-222-3p and β-catenin protein after SDC-1 knockdown neither in MCF-7 nor MDA-MB-231 cell lines. Conclusion: SDC-1 is not a regulator for miR-222-3p expression and the altered cell behavior mediated by SDC-1 knockdown in MCF-7 and MDA-MB-231 breast cancer cells is miR-222-3p-independent. Received: 15 February 2019, Accepted: 18 February 2019