title: ALEX1 suppresses colony formation ability of human colorectal carcinoma cell lines.
abstract: Arm protein lost in epithelial cancers, on chromosome X (ALEX; also known as armadillo repeat containing, X-linked [ARMCX]) is a novel subgroup within the armadillo (ARM) family, which has several ARM repeat domains. The biological function of classical ARM family members such as β-catenin is well understood, but that of the ALEX/ARMCX family members is largely unknown. Here we evaluate the effects of ALEX1 overexpression on in vitro colony formation ability and expression of ALEX1 mRNA in human colorectal tumor. Overexpression of ALEX1 suppressed the anchorage-dependent and -independent colony formation of human colorectal carcinoma cell lines by the study of stable clones of HCT116 cells expressing ALEX1 protein. Bisulfite genomic sequencing revealed that the promoter region of ALEX1 gene was highly methylated in both HCT116 and SW480 cells in comparison with PANC-1 and MCF-7 cells, which express endogenous ALEX1 mRNA, indicating the capability of promoter methylation to silence ALEX1 gene in HCT116 and SW480 cells. Our current findings suggest that overexpression of ALEX1 play a negative role in human colorectal tumorigenesis.
authors.affiliation: Department of Digestive Surgery, Saitama International Medical Center, Saitama Medical University, Saitama, Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Iseki
authors.forename: Akihiko
authors.initials: A
authors.lastname: Takeda
authors.forename: Toshiwo
authors.initials: T
authors.lastname: Andoh
authors.forename: Koki
authors.initials: K
authors.lastname: Kuwabara
authors.forename: Norio
authors.initials: N
authors.lastname: Takahashi
authors.forename: Igor V
authors.initials: IV
authors.lastname: Kurochkin
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ishida
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okazaki
authors.forename: Isamu
authors.initials: I
authors.lastname: Koyama
mesh_terms: D051186:Armadillo Domain Proteins / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D002448:Cell Adhesion / Q000235:genetics; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D015972:Gene Expression Regulation, Neoplastic; D045325:HCT116 Cells; D006801:Humans; D061986:MCF-7 Cells; D015513:Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA / Q000379:methods; D014410:Tumor Stem Cell Assay / Q000379:methods*
chemical_list: C422103:ARMCX1 protein, human; D051186:Armadillo Domain Proteins; D015513:Oncogene Proteins