Abstract
Purpose: To study the role and therapeutic potential of miR-9 in the treatment of breast cancer.Methods: The expression of miR-9 was evaluated in breast cancer cell lines using quantitative real-time polymerase chain reaction (qRT-PCR). Proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay, while cell migration was assessed by wound healing assay. Transfections were performed with Lipofectamine 2000 reagent. Overexpression of miR-9 was performed by transfecting breast cancer cells with miR-9 mimics, and suppression of STAT3 was done with Si-RNA construct. Target identification was carried out using target scan, while protein expression was determined with immunoblotting.Results: The results revealed that miR-9 was significantly (p < 0.05) downregulated in the breast cancer cell lines. Overexpression of miR-9 significantly (p < 0.05) inhibited the proliferation of the breast cancer cells by initiation of apoptosis and cell cycle arrest. In addition, MiR-9 overexpression inhibited the migration of the breast cancer cells. TargetScan analysis showed that STAT3 was the potential target of miR-9: it was significantly downregulated in breast cancer cells overexpressing miR-9. Silencing of STAT3 exerted inhibitory effects on the proliferation and migration of breast cancer cells similar to that of miR-9 overexpression.Conclusion: MiR-9 regulates the proliferation of human breast cancer by targeting STAT3. Hence, miR-9 can be potentially applied as a therapeutic agent for the management of breast cancer.Keywords: Breast cancer, MicroRNA-9, STAT3, Apoptosis, Bioinformatic analysis
Highlights
Breast cancer is one of the prevalent cancers among woman, and it causes considerable mortality throughout the world [1]
The expression of miR-9 was studied in six different breast cancer cell lines and one normal cell line by quantitative RT-PCR
The results showed that the expression of miR-9 was significantly downregulated in all the breast cancer cell lines (Figure 1 A)
Summary
Breast cancer is one of the prevalent cancers among woman, and it causes considerable mortality throughout the world [1]. The miRNAs do not code for any protein and are generally very short RNA molecules consisting of about 20 nucleotides [5] They have been shown to control a number of processes, including cell division [6]. After incubating the cells for about six days, they were washed with PBS and fixed with methanol. They were stained with crystal violet and examined by microscopy. The therapeutic potential of miR-9 in breast cancer was investigated. After lysis of the breast cancer cells in RIPA lysis buffer, the protein content of the each lysate was estimated by BCA assay, and the samples were thereafter subjected to separation using SDSPAGE.
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