title: Twist modulates breast cancer stem cells by transcriptional regulation of CD24 expression.
abstract: The cancer stem cell paradigm postulates that dysregulated tissue-specific stem cells or progenitor cells are precursors for cancer biogenesis. Consequently, identifying cancer stem cells is crucial to our understanding of cancer progression and for the development of novel therapeutic agents. In this study, we demonstrate that the overexpression of Twist in breast cells can promote the generation of a breast cancer stem cell phenotype characterized by the high expression of CD44, little or no expression of CD24, and increased aldehyde dehydrogenase 1 activity, independent of the epithelial-mesenchymal transition. In addition, Twist-overexpressing cells exhibit high efflux of Hoechst 33342 and Rhodamine 123 as a result of increased expression of ABCC1 (MRP1) transporters, a property of cancer stem cells. Moreover, we show that transient expression of Twist can induce the stem cell phenotype in multiple breast cell lines and that decreasing Twist expression by short hairpin RNA in Twist-overexpressing transgenic cell lines MCF-10A/Twist and MCF-7/Twist as well as in MDA-MB-231 partially reverses the stem cell molecular signature. Importantly, we show that inoculums of only 20 cells of the Twist-overexpressing CD44(+)/CD24(-/low) subpopulation are capable of forming tumors in the mammary fat pad of severe combined immunodeficient mice. Finally, with respect to mechanism, we provide data to indicate that Twist transcriptionally regulates CD24 expression in breast cancer cells. Taken together, our data demonstrate the direct involvement of Twist in generating a breast cancer stem cell phenotype through down-regulation of CD24 expression and independent of an epithelial-mesenchymal transition.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Traylor 338, Baltimore, MD 21205, USA.
authors.forename: Farhad
authors.initials: F
authors.lastname: Vesuna
authors.forename: Ala
authors.initials: A
authors.lastname: Lisok
authors.forename: Brian
authors.initials: B
authors.lastname: Kimble
authors.forename: Venu
authors.initials: V
authors.lastname: Raman
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism; D000080924:Aldehyde Dehydrogenase 1 Family; D000818:Animals; D001665:Binding Sites; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051927:CD24 Antigen / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D005260:Female; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008325:Mammary Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051379:Mice; D016513:Mice, SCID; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D034622:RNA Interference; D050697:Retinal Dehydrogenase; D014158:Transcription, Genetic; D014183:Transplantation, Heterologous; D051879:Twist-Related Protein 1 / Q000235:genetics / Q000378:metabolism*
chemical_list: D051927:CD24 Antigen; C497889:CD24 protein, human; D018960:Hyaluronan Receptors; D007527:Isoenzymes; D009687:Nuclear Proteins; C103173:TWIST1 protein, human; D051879:Twist-Related Protein 1; D000080924:Aldehyde Dehydrogenase 1 Family; D000444:Aldehyde Dehydrogenase; C510223:ALDH1A1 protein, human; C515028:ALDH1A1 protein, mouse; D050697:Retinal Dehydrogenase