miRNA-342 Regulates CEACAM1-induced Lumen Formation in a Three-dimensional Model of Mammary Gland Morphogenesis.
Lumen formation of breast epithelium is rapidly lost during tumorigenesis along with expression of cell adhesion molecule CEACAM1. CEACAM1 induces lumena in a three-dimensional culture of MCF7/CEACAM1 cells that otherwise fail to form lumena. We hypothesized miRNAs may be involved because >400 genes were up- or down-regulated in MCF7/CEACAM1 cells and miRNAs may modify global expression patterns. Comparative analysis of miRNA expression in MCF7 versus MCF7/CEACAM1 cells revealed two miRNAs significantly down-regulated (hsa-miR-30a-3p by 6.73-fold and hsa-miR-342-5p by 5.68-fold). Location of miR-342 within an intron of the EVL gene, hypermethylated and involved in tumorigenesis, suggested that miR-342 overexpression may block lumen formation. In fact, overexpression of miR-342 in MCF7/CEACAM1 cells significantly blocked lumen formation (p < 0.001). ID4, a dominant-negative inhibitor of basic helix-loop-helix transcription factors, up-regulated in MCF7/CEACAM1 cells, down-regulated in breast cancer, and containing a miR-342 binding site, was tested as a potential target of miR-342. The ratio of ID4 to miR-342 increased from 1:2 in MCF7 cells to 30:1 in MCF7/CEACAM1 cells and a miR-342 inhibitor was able to induce 3'-UTR ID4 reporter activity in MCF7 cells. Because 5-methylcytosine methyltransferase DNMT1 is also a potential target of miR-342, we inhibited miR-342 in MCF7 cells and found DNMT1 was up-regulated with no change in EVL expression, suggesting that miR-342 regulates DNMT1 expression but DNMT1 does not affect the EVL expression in these cells. We conclude that the regulation of lumen formation by miR-342 involves at least two of its known targets, namely ID4 and DNMT1.
From the City of Hope Irell & Manella Graduate School of Biological Sciences, Duarte, California 91010 and the Department of Immunology, Beckman Research Institute of City of Hope, Duarte, California 91010.
Chunyue
C
Weng
the Department of Immunology, Beckman Research Institute of City of Hope, Duarte, California 91010.
Tung
T
Nguyen
the Department of Immunology, Beckman Research Institute of City of Hope, Duarte, California 91010 jshively@coh.org.
John E
JE
Shively
D020413:3' Untranslated Regions; D015703:Antigens, CD / Q000096:biosynthesis* / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D006801:Humans; D051796:Inhibitor of Differentiation Proteins / Q000235:genetics / Q000378:metabolism; D061986:MCF-7 Cells; D042361:Mammary Glands, Human / Q000378:metabolism*; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D008954:Models, Biological; D009024:Morphogenesis
D020413:3' Untranslated Regions; D015703:Antigens, CD; C069847:CD66 antigens; D015815:Cell Adhesion Molecules; C484449:EVL protein, human; C490128:ID4 protein, human; D051796:Inhibitor of Differentiation Proteins; C546176:MIRN342 microRNA, human; D035683:MicroRNAs; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human
CEACAM1; RNA interference (RNAi); breast cancer; cell adhesion; mammary gland; microRNA (miRNA)