Abstract |
Background /Aims: Recent studies of microRNA ( miRNA) involvement in tumorigenesis have indicated the critical role of these non-coding small RNAs in malignant transformation, but the prognostic role, if any, of miRNAs in breast cancer remains undetermined. Therefore, we assessed the prognostic significance of microRNA-9 (miR-9) and miR-221 in breast cancer toward the goal of understanding the contribution(s) of these miRNAs to cancer cell stemness. METHODS: The level of each of miR-9 and miR-221 in 206 paired laser capture microdissected tumor cells and non- tumor cells was determined by quantitative reverse transcription-PCR (qRT-PCR). The relationship between the miRNA signature and clinicopathological data and prognosis of breast cancer was assessed. Identification of a stem cell-enriched side population was achieved with fluorescence-activated cell sorting and a sphere-forming assay. Wound healing, Boyden chamber assays, and western blotting were used to study the contribution of each miRNA to tumor cell migration and invasion. RESULTS: We found that induction of miR-9 and miR-221 mimics conferred side-population cells to form spheroidal tumor colonies in suspension culture that maintained the mesenchymal stem-cell potential in non-invasive MCF-7 breast cancer cells. In contrast, knockdown of both miR-9 and miR-221 in invasive MDA-MB-231 breast cancer cells dramatically decreased the number of side-population colonies with stem cell-like potency, which reduced the capacity for tumor-cell renewal, invasion, and migration. Clinically, the mean proportion of miR-9- or miR-221-overexpressing cells was significantly greater in tumor cells compared with non- tumor cells (P < 0.05). Increased levels of miR-9 and miR-221 in breast tissue portended a significantly elevated risk of progression to malignancy with respect to larger tumor size, poor differentiation, late-stage evolution, lymph-node metastasis (P < 0.05), and lower overall survival (Ptrend = 0.017; eight-year follow-up). CONCLUSION: Our findings provide strong evidence that miR-9 and miR-221 can enhance the generation of cancer stem cells to yield an invasive phenotype and that overexpression of these miRNAs predicts a poor outcome for breast cancer patients.
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Authors | Chun-Wen Cheng, Jyh-Cherng Yu, Yi-Hsien Hsieh, Wen-Ling Liao, Jia-Ching Shieh, Chung-Chin Yao, Huei-Jane Lee, Po-Ming Chen, Pei-Ei Wu, Chen-Yang Shen |
Journal | Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology
(Cell Physiol Biochem)
Vol. 48
Issue 5
Pg. 2205-2218
( 2018)
ISSN: 1421-9778 [Electronic] Germany |
PMID | 30110679
(Publication Type: Journal Article)
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Copyright | © 2018 The Author(s). Published by S. Karger AG, Basel. |
Chemical References |
- AC133 Antigen
- Antagomirs
- MIRN221 microRNA, human
- MIRN92 microRNA, human
- MicroRNAs
- Nanog Homeobox Protein
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Topics |
- AC133 Antigen
(metabolism)
- Adult
- Antagomirs
(metabolism)
- Area Under Curve
- Breast Neoplasms
(diagnosis, genetics, mortality, pathology)
- Cell Line, Tumor
- Cell Movement
- Female
- Humans
- Lymphatic Metastasis
- MCF-7 Cells
- MicroRNAs
(antagonists & inhibitors, genetics, metabolism)
- Middle Aged
- Nanog Homeobox Protein
(metabolism)
- Neoplastic Stem Cells
(cytology, metabolism)
- Prognosis
- Proportional Hazards Models
- ROC Curve
- Survival Rate
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