title: Sarcoendoplasmic reticulum Ca(2+) ATPase type 2 downregulated in human oral squamous cell carcinoma.
abstract: Mice with a heterozygous deletion of the Atp2a2 gene (Atp2a2(+/-)) encoding SERCA2 spontaneously develop SCCs of the skin and upper digestive tract, including the oral cavity. To elucidate the contribution of ATP2A2 to human oral carcinogenesis, we analyzed genetic and epigenetic changes as well as mRNA and protein expression in primary OSCCs and OPLs. With the exception of one OSCC-derived cell line showing a 12 bp deletion of ATP2A2, we found no mutations in the coding sequence of the gene in primary OSCCs (n = 52), OPLs (n = 32) and cell lines (n = 8). In immunohistochemistry, however, high frequencies of ATP2A2 downregulation were evident not only in primary OSCCs (42%, 42/100) but also in OPLs (31%, 10/32). Real-time quantitative RT-PCR data were consistent with the protein expression status. Aberrant DNA methylation within ATP2A2 also was detected in 9 of 30 ATP2A2-downregulated OSCCs. Moreover, restoration or elevated expression of the ATP2A2 protein was induced in most of the cell lines showing ATP2A2 methylation after treatment with 5-aza-2'-dC, a DNA demethylating agent. These results suggest that inactivation of the ATP2A2 gene is a frequent and early event during oral carcinogenesis and that loss of expression may be regulated partly by an epigenetic mechanism.
authors.affiliation: Department of Clinical Molecular Biology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Endo
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Uzawa
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Mochida
authors.forename: Masashi
authors.initials: M
authors.lastname: Shiiba
authors.forename: Hiroki
authors.initials: H
authors.lastname: Bukawa
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Yokoe
authors.forename: Hideki
authors.initials: H
authors.lastname: Tanzawa
mesh_terms: D000328:Adult; D000368:Aged; D000252:Calcium-Transporting ATPases / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000201:enzymology*; D019175:DNA Methylation; D015536:Down-Regulation; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D019254:Genes, bcl-2; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000201:enzymology*; D009154:Mutation; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases
chemical_list: D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; C506946:ATP2A2 protein, human; D000252:Calcium-Transporting ATPases