@misc{oai:repo.qst.go.jp:00070242,
 author = {Yoshii, Yukie and Waki, Atsuo and Kiyono, Yashushi and Yoshii, Hiroshi and Furukawa, Takako and Okazawa, Hidehiko and Fujibayashi, Yasuhisa and et.al and 吉井 幸恵 and 古川 高子 and 藤林 康久},
 month = {Sep},
 note = {3D multicellular spheroid (MCS) of tumor cells is expected to be a useful in vitro model reflecting characteristics of in vivo tumors, in tumor research. However, conventional methods to form 3D MCSs have problems in convenience and cell viability. Here we propose a method to acquire 3D MCSs, which are constructed from spontaneous migration and gathering of tumor cells and sustain high proliferation and viability, by simply culturing cells on the plates with nano-sized pattern scaffoldings on surface of the bottom (nano-pattern culture). In this study, we examined detailed characteristics of 3D MCSs constructed with nano-pattern culture to evaluate its utility in molecular imaging research. 
Morphology and formation process of the MCSs were examined with an inverted light microscope and SEM and with time-lapse analysis, respectively. Proliferation, viability, gene expression profile and response to hypoxia of the MCSs were also investigated. Transcription of hypoxia-inducible factor 1 (HIF-1) was examined with GFP reporter assay. 
Our observations showed that tumor cells elongated foots to grasp nano-sized pattern scaffoldings, migrated and gathered each other, which results in formation of adherent MCSs. On the other hand, gene expression profile of the cells on nano-sized pattern scaffoldings was mostly similar to that of 2D monolayer cells in cell adhesion and motility, which indicates that nano-pattern culture can liberate latent potential of tumor cells in cell adhesion and motility rather than 2D culture. Additionally, the mature MCSs constructed with nano-pattern culture were up-regulated in gene expression of multicellular organismal development and response to hypoxia. Transcription of HIF-1 and gene expression of HIF-1 target genes were also activated and there were hypoxic regions detected by pimonidazol binding, in the MCSs from this culture. 
These facts demonstrate that 3D culture system with nano-sized pattern scaffoldings can provide a model for cell migration, construction of organizational structure and hypoxia in 3D formation, which are linked with characteristics of in vivo tumors. Therefore, the nano-pattern culture system could be useful in development of molecular imaging probes., World  Molecular Imaging Congress 2010},
 title = {3D tumor spheroids constructed with nano-sized pattern scaffoldings: a novel model for molecular imaging research},
 year = {2010}
}