title: Involvement of aberrant DNA methylation on reduced expression of lysophosphatidic acid receptor-1 gene in rat tumor cell lines.
abstract: Lysophosphatidic acid (LPA) is a bioactive phospholipid that stimulates cell proliferation, migration, and protects cells from apoptosis. It interacts with specific G protein-coupled transmembrane receptors. Recently, it has been reported that alterations of LPA receptor expression might be important in the malignant transformation of tumor cells. Therefore, to assess an involvement of DNA methylation in reduced expression of the LPA receptor-1 (lpa1) gene, we investigated the expression of the lpa1 gene and its DNA methylation patterns in rat tumor cell lines. Both rat brain-derived neuroblastoma B103 and liver-derived hepatoma RH7777 cells used in this study indicated no expression of lpa1. For the analysis of methylation status, bisulfite sequencing was performed with B103 and RH7777 cells, comparing with other lpa1 expressed cells and normal tissues of brain and liver. The lpa1 expressed cells and tissues were all unmethylated in this region of lpa1. In contrast, both B103 and RH7777 cells were highly methylated, correlating with reduced expression of the lpa1. Treatment with 5-aza 2'-deoxycytidine induced expression of lpa1 gene in B103 and RH7777 cells after 24h. In RH7777 cells treated with 5-aza 2'-deoxycytidine, stress fiber formation was also observed in response to LPA in RH7777 cells, but not in untreated RH7777 cells. These results suggest that aberrant DNA methylation of the lpa1 gene may be involved in its reduced expression in rat tumor cells.
authors.affiliation: Laboratory of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502, Japan. ttujiuch@life.kindai.ac.jp <ttujiuch@life.kindai.ac.jp>
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Tsujiuchi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Shimizu
authors.forename: Mariko
authors.initials: M
authors.lastname: Onishi
authors.forename: Eriko
authors.initials: E
authors.lastname: Sugata
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Fujii
authors.forename: Toshio
authors.initials: T
authors.lastname: Mori
authors.forename: Kanya
authors.initials: K
authors.lastname: Honoki
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Fukushima
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D045744:Cell Line, Tumor; D019175:DNA Methylation; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D008099:Liver / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D049368:Receptors, Lysophosphatidic Acid / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D049368:Receptors, Lysophosphatidic Acid