PurposeThe purpose of this study is to evaluate the effects of miR-628 on migration and invasion of breast cancer stem cells (CSCs), which are essential for tumor recurrence and metastasis.Materials and methodsQuantitative reverse transcription-polymerase chain reaction was used to determine the expression of microRNAs and mRNAs. A subpopulation of CD44+/CD24− breast CSCs were sorted by flow cytometry. Transwell assays were used to evaluate cell migration and invasion. Luciferase reporter assays were performed to verify whether miR-628 targeted SOS Ras/Rac guanine nucleotide exchange factor 1 (SOS1). pcDNA3.1(+)-SOS1 was constructed for overexpressing SOS1 after transfection.ResultsCompared with primary breast cancer cells, bone metastatic breast cancer cells showed significant downregulation of miR-628. The CD44+/CD24− breast CSC subpopulations in MDA-MB-231 and MCF-7 cell lines were analyzed and sorted. Transfection with an miR-628 mimic significantly suppressed the migration and invasion of these breast CSCs by targeting SOS1, which plays an essential role in epithelial-to-mesenchymal transition. Overexpression of SOS1 rescued miR-628-mediated migration and invasion by upregulating Snail and vimentin, and downregulating E-cadherin.ConclusionmiR-628 suppressed migration and invasion of breast CSCs of MDA-MB-231 and MCF-7 cells by directly targeting SOS1. Enhancement of miR-628 expression might be an effective strategy for managing breast cancer metastasis.

The Editor and Publisher of Onco Targets and Therapy are retracting the published article. Concerns were raised following the authors request to correct an error in Figure 6. It was found that images in Figure 3D and 6C had been duplicated. Specifically,• The image for Figure 3D, MCF-7, miR-628 has been duplicated with the image from Figure 6C, MCF-7, miR-628 +pcDNA.• The image for Figure 6C, MCF-7, miR-628+pcDNA has been duplicated with the image from Figure 6C, MCF-7, miR-628+pcDNA-SOS1.The authors responded to our follow up queries but were unable to provide a satisfactory explanation for the duplicated images. Additionally, the authors explained they could only provide partial data for their study due to the elapsed time since study completion. As the findings could not be verified the Editor and Publisher made the decision to retract the article and the authors agreed with this.We have been informed in our decision-making by our editorial policies and the COPE guidelines.The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as "Retracted".