Breast cancer is a malignant tumor with the highest incidence among women. Breast cancer metastasis is the major cause of treatment failure and mortality among such patients. MicroRNAs (miRNAs) are a class of small molecular non-coding regulatory RNAs, which act as oncogenes or tumor suppressors in breast cancer. miRNA-10b has been found to exhibit a high expression level in advanced and metastatic breast cancer, and is closely related to breast cancer metastasis. An miRNA sponge is an mRNA with several repeated sequences of complete or incomplete complementarity to the natural miRNA in its 3' non-translating region. It acts as a sponge adsorbing miRNAs and ensures their separation from their targets and inhibits their function. The present study designed a sponge plasmid against miRNA-10b and transiently transfected it into high and low metastatic human breast cancer cell lines MDA-MB-231 and MCF-7, and analyzed the effects of the miRNA-10b sponge on the growth and proliferation, migration and invasion in these cell lines. qRT-PCR results found that the sponge plasmid effectively inhibited the expression of miRNA-10b, and upregulated the expression of the miRNA‑10b target protein HOXD-10. The results from the CCK-8 assay found that the miRNA-10b sponge inhibited the growth of breast cancer cell lines MDA-MB-231 and MCF-7. Results of the plate cloning experiments indicated that the miRNA-10b sponge suppressed the colony formation of the MDA-MB-231 and MCF-7 cells. The results of wound healing and Transwell assays showed that the miRNA-10b sponge inhibited the migration and invasion of the breast cancer cell lines MDA-MB-231 and MCF-7. Our results demonstrated that the miRNA-10b sponge effectively inhibited the growth and proliferation of breast cancer MDA-MB-231 and MCF-7 cells. In addition, it also restrained the migration and invasion of human highly metastatic breast cancer MDA-MB-231 cells.

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