title: Mitochondrial DNA reduced by hypoxic conditions in three-dimensional (3D) spheroid cell cultures.
abstract: Three-dimensional (3D) cell culture reflects many of the important properties of solid tumors, such as the inadequate diffusion of oxygen that results in hypoxia. To understand the mitochondrial states in cancer, we performed comparisons of the levels of mitochondrial DNA (mtDNA), fusion- and fission-related mitochondrial messenger RNA (mRNA), and mitochondrial protein expression between monolayer (2D)- and 3D-cultured cancer cells. The mtDNA levels were observed to be significantly lower in the 3D cells compared with the monolayer cells. In contrast, the differences in expression of the mitochondrial fusion- and fission-related mRNAs and mitochondrial proteins between 2D- and 3D-cultured cancer cells were not significant, as shown by real-time PCR and immunoblot analysis. Therefore, although mtDNA levels decrease as a whole during 3D culture, this does not appear to affect the fusion and fission of individual mitochondria. Indeed, the factors regulating mitochondrial dynamics during 3D cell culture remain unclear. This study provides the basis for future, more detailed studies on the regulation of mtDNA.
authors.affiliation: Laboratory of Cellular and Molecular Biochemistry, Department of Materials and Life Science, Seikei University, 3-3-1 Kichijoji Kitamachi, Musashino, Tokyo, 180-8633, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Chiba
authors.forename: Chikako
authors.initials: C
authors.lastname: Yokoyama
authors.forename: Mai
authors.initials: M
authors.lastname: Okada
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hisatomi
mesh_terms: D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D004272:DNA, Mitochondrial; D051456:Gene Flow; D006801:Humans; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism*; D063154:Mitochondrial Dynamics / Q000235:genetics; D000091402:Prohibitins; D012333:RNA, Messenger / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D018874:Spheroids, Cellular; D014407:Tumor Cells, Cultured
chemical_list: D004272:DNA, Mitochondrial; D000091402:Prohibitins; D012333:RNA, Messenger; D012097:Repressor Proteins