Prolonged mammosphere culture of MCF-7 cells induces an EMT and repression of the estrogen receptor by microRNAs
- نوع فایل : کتاب
- زبان : انگلیسی
- مؤلف : I. K. Guttilla K. N. Phoenix X. Hong J. S. Tirnauer K. P. Claffey B. A. White
- چاپ و سال / کشور: 2011
Description
Mammosphere culture has been used widely for the enrichment of mammary epithelial stem cells and breast cancer stem cells (CSCs). Epithelial-to-mesenchymal transition (EMT) also induces stem cell features in normal and transformed mammary cells. We examined whether mammosphere culture conditions per se induced EMT in the epithelial MCF-7 breast cancer cell line. MCF- 7 cells were cultured as mammospheres for 5 weeks, with dispersal and reseeding at the end of each week. This mammosphere culture induced a complete EMT by 3 weeks. Return of the cells to standard adherent culture conditions in serum-supplemented media generated a cell population (called MCF-7M cells), which displays a stable mesenchymal and CSC-like CD44?/CD24-/low phenotype. EMT was accompanied by a stable, marked increase in EMT-associated transcription factors and mesenchymal markers, and a decrease in epithelial markers and estrogen receptor a (ERa). MCF-7M cells showed increased motility, proliferation and chemoresistance in vitro, and produced larger tumors in immunodeficient mice with or without estrogen supplementation. MicroRNA analysis showed suppression of miR-200c, miR-203, and miR-205; and increases in miR-222 and miR-221. Antisense hairpin RNA inhibitor targeting miR-221 resulted in re-expression of ERa in MCF-7M cells. This study provides the first example of mammosphere culture conditions inducing EMT and of EMT regulating microRNAs that target ERa.
DOI 10.1007/s10549-011-1534-y Received: 10 February 2011 / Accepted: 16 April 2011
