a systematic screen for micro-rnas regulating the canonical wnt pathway系统屏幕微- rnas规范规范wnt通路.pdfVIP

A Systematic Screen for Micro-RNAs Regulating the Canonical Wnt Pathway 1 1 2 2 1 Roman Anton , Sujash S. Chatterjee , Julia Simundza , Pamela Cowin , Ramanuj DasGupta * 1 Cancer Institute/Department of Pharmacology, New York University Langone Medical Center, New York University, New York, New York, United States of America, 2 Departments of Cell Biology and Dermatology, New York University Langone Medical Center, New York University, New York, New York, United States of America Abstract MicroRNAs (miRs) and the canonical Wnt pathway are known to be dysregulated in human cancers and play key roles during cancer initiation and progression. To identify miRs that can modulate the activity of the Wnt pathway we performed a cell-based overexpression screen of 470 miRs in human HEK293 cells. We identified 38 candidate miRs that either activate or repress the canonical Wnt pathway. A literature survey of all verified candidate miRs revealed that the Wnt-repressing miRs tend to be anti-oncomiRs and down-regulated in cancers while Wnt-activating miRs tend to be oncomiRs and upregulated during tumorigenesis. Epistasis-based functional validation of three candidate miRs, miR-1, miR-25 and miR- 613, confirmed their inhibitory role in repressing the Wnt pathway and suggest that while miR-25 may function at the level ˆ of a-catenin (b-cat), miR-1 and miR-613 act upstream of b-cat. Both miR-25 and miR-1 inhibit cell proliferation and viability during selection of human colon cancer cell lines that exhibit dysregulated Wnt signaling. Finally, transduction of miR-1 expressing lentiviruses into primary mammary organoids derived from Conductin-lacZ mice significantly reduced the expression of