Identification of two novel phenotypically distinct breast cancer cell subsets based on Sox2 transcription activity
| Autor: | Joel D. Pearson, Peng Wang, Raymond Lai, Robert J. Ingham, Jingdong Zhang, Fang Wu, Karen Jung, Kathleen M. Bone, Xiaoxia Ye, Yupo Ma, Todd P. W. McMullen |
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| Rok vydání: | 2012 |
| Předmět: |
Homeobox protein NANOG
Transcription Genetic Cellular differentiation Breast Neoplasms Biology Integrin alpha6 03 medical and health sciences Glycogen Synthase Kinase 3 0302 clinical medicine stomatognathic system SOX2 Cancer stem cell Genes Reporter Cell Line Tumor Humans Cyclin D1 RNA Small Interfering Transcription factor STAT4 beta Catenin 030304 developmental biology Cell Proliferation Homeodomain Proteins 0303 health sciences Glycogen Synthase Kinase 3 beta Cell growth SOXB1 Transcription Factors fungi Promoter Cell Biology DNA Nanog Homeobox Protein Molecular biology 3. Good health Phenotype 030220 oncology & carcinogenesis embryonic structures MCF-7 Cells Female RNA Interference sense organs biological phenomena cell phenomena and immunity |
| Zdroj: | Cellular signalling. 24(11) |
| ISSN: | 1873-3913 |
| Popis: | Sox2 (sex-determining region Y-box protein 2) is a transcription factor regulating pluripotency in embryonic stem cells. Sox2 is aberrantly expressed in breast and other cancers, though its biological significance remains widely unexplored. To understand the significance of this aberrancy, we assessed the transcription activity of Sox2 in two Sox2-expressing breast cancer cell lines, MCF7 and ZR751, using a lentiviral Sox2 GFP reporter vector. Surprisingly, Sox2 transcription activity, as measured by GFP expression encoded in a Sox2 reporter construct, was detectable only in a small subset of cells in both cell lines. Purification of GFP+ cells (cells with Sox2 activity) and GFP- cells (cells without Sox2 activity) was enriched for two phenotypically distinct cell populations in both MCF7 and ZR751 cell lines. Specifically, GFP+ cells formed significantly more colonies in methylcellulose and more mammospheres in vitro compared to GFP- cells. These phenotypic differences are directly linked to Sox2 as siRNA knockdown of Sox2 in GFP+ cells abolished these abilities. To provide a mechanistic explanation to our observations, we performed gel shift and chromatin immunoprecipitation studies; Sox2 was found to bind to its DNA binding consensus sequence and the promoters of Cyclin D1 and Nanog (two known Sox2 downstream targets) only in GFP+ cells. GFP+ cells also up-regulated CD49f, phospho-GSK3β, and β-catenin. In summary, we have identified two novel phenotypically distinct cell subsets in two breast cancer cell lines based on their differential Sox2 transcription activity. We demonstrate that Sox2 transcription activity, and not its protein expression alone, underlies the tumorigenicity and cancer stem cell-like phenotypes in breast cancers. |
| Databáze: | OpenAIRE |
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