title: Preferential expression of cancer/testis genes in cancer stem-like cells: proposal of a novel sub-category, cancer/testis/stem gene.
abstract: Cancer/testis (CT) antigens encoded by CT genes are immunogenic antigens, and the expression of CT gene is strictly restricted to only the testis among mature organs. Therefore, CT antigens are promising candidates for cancer immunotherapy. In a previous study, we identified a novel CT antigen, DNAJB8. DNAJB8 was found to be preferentially expressed in cancer stem-like cells (CSCs)/cancer-initiating cells (CICs), and it is thus a novel CSC antigen. In this study, we hypothesized that CT genes are preferentially expressed in CSCs/CICs rather than in non-CSCs/-CICs and we examined the expression of CT genes in CSCs/CICs. The expression of 74 CT genes was evaluated in side population (SP) cells (=CSC) and main population (MP) cells (=non-CSC) derived from LHK2 lung adenocarcinoma cells, SW480 colon adenocarcinoma cells and MCF7 breast adenocarcinoma cells by RT-PCR and real-time PCR. Eighteen genes (MAGEA2, MAGEA3, MAGEA4, MAGEA6, MAGEA12, MAGEB2, GAGE1, GAGE8, SPANXA1, SPANXB1, SPANXC, XAGE2, SPA17, BORIS, PLU-1, SGY-1, TEX15 and CT45A1) showed higher expression levels in SP cells than in MP cells, whereas 10 genes (BAGE1, BAGE2, BAGE4, BAGE5, XAGE1, LIP1, D40, HCA661, TDRD1 and TPTE) showed similar expression levels in SP cells and MP cells. Thus, considerable numbers of CT genes showed preferential expression in CSCs/CICs. We therefore propose a novel sub-category of CT genes in this report: cancer/testis/stem (CTS) genes.
authors.affiliation: Department of Pathology, Sapporo Medical University School of Medicine, Sapporo, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Yamada
authors.forename: A
authors.initials: A
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Torigoe
authors.forename: R
authors.initials: R
authors.lastname: Morita
authors.forename: Y
authors.initials: Y
authors.lastname: Tamura
authors.forename: T
authors.initials: T
authors.lastname: Tsukahara
authors.forename: T
authors.initials: T
authors.lastname: Kanaseki
authors.forename: T
authors.initials: T
authors.lastname: Kubo
authors.forename: K
authors.initials: K
authors.lastname: Watarai
authors.forename: T
authors.initials: T
authors.lastname: Kondo
authors.forename: Y
authors.initials: Y
authors.lastname: Hirohashi
authors.forename: N
authors.initials: N
authors.lastname: Sato
mesh_terms: D000951:Antigens, Neoplasm / Q000235:genetics*; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D061986:MCF-7 Cells; D008297:Male; D014411:Neoplastic Stem Cells / Q000276:immunology*; D060888:Real-Time Polymerase Chain Reaction; D013091:Spermatogenesis / Q000235:genetics; D013737:Testis / Q000276:immunology*
chemical_list: D000951:Antigens, Neoplasm