title: The MYC 3' Wnt-Responsive Element Drives Oncogenic MYC Expression in Human Colorectal Cancer Cells.
abstract: Mutations in components of the Wnt/β-catenin signaling pathway drive colorectal cancer (CRC) by deregulating expression of downstream target genes including the c-MYC proto-oncogene (MYC). The critical regulatory DNA enhancer elements that control oncogenic MYC expression in CRC have yet to be fully elucidated. In previous reports, we correlated T-cell factor (TCF) and β-catenin binding to the MYC 3' Wnt responsive DNA element (MYC 3' WRE) with MYC expression in HCT116 cells. Here we used CRISPR/Cas9 to determine whether this element is a critical driver of MYC. We isolated a clonal population of cells that contained a deletion of a single TCF binding element (TBE) within the MYC 3' WRE. This deletion reduced TCF/β-catenin binding to this regulatory element and decreased MYC expression. Using RNA-Seq analysis, we found altered expression of genes that regulate metabolic processes, many of which are known MYC target genes. We found that 3' WRE-Mut cells displayed a reduced proliferative capacity, diminished clonogenic growth, and a decreased potential to form tumors in vivo. These findings indicate that the MYC 3' WRE is a critical driver of oncogenic MYC expression and suggest that this element may serve as a therapeutic target for CRC.
authors.affiliation: Department of Biochemistry &amp; Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. sar333@psu.edu.
authors.forename: Sherri A
authors.initials: SA
authors.lastname: Rennoll
authors.affiliation: Department of Biochemistry &amp; Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. mhartman3@hmc.psu.edu.
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Eshelman
authors.affiliation: Department of Biochemistry &amp; Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. wmk113@psu.edu.
authors.forename: Wesley M
authors.initials: WM
authors.lastname: Raup-Konsavage
authors.affiliation: Department of Biochemistry &amp; Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. yimamura@hmc.psu.edu.|Department of Pharmacology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. yimamura@hmc.psu.edu.|The Institute for Personalized Medicine, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. yimamura@hmc.psu.edu.
authors.forename: Yuka Imamura
authors.initials: YI
authors.lastname: Kawasawa
authors.affiliation: Department of Biochemistry &amp; Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. gyochum@hmc.psu.edu.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Yochum
keywords: MYC; Wnt-responsive element; colorectal cancer; β-catenin