title: Visualization and characterization of cancer stem-like cells in cervical cancer.
abstract: Cancer stem cells (CSCs), defined by their differentiation capacity, self-renewal capacity, and maintenance of proliferation, have been identified in many tumors, including cervical cancer. Current studies identify CSCs by several specific biomarkers; however, it is difficult to monitor cervical CSCs in real-time in vitro and in vivo. Recent research reported the visualization of CSCs in breast cancer and gliomas using green fluorescent protein, ZsGreen, fused to a degron motif ornithine decarboxylase (ODC), which is destroyed by proteasomes. Accordingly, CSCs have low 26S proteasome activity, whereas non-CSCs have high 26S proteasome activity. Therefore, it is possible to observe CSCs by their accumulation of the fluorescent ZsGreen protein. In this study, we investigated optical imaging parameters to evaluate CSCs using two human cervical cancer cell lines: CaSki and HeLa. We defined populations as cell types having high- and low ZsGreen-cODC (high- and low-Zs, respectively) expression levels. The results of a sphere-forming assay revealed that the self-renewal ability of the high-Zs population was significantly higher than that of the low-Zs population. A tumorigenicity assay confirmed that the high-Zs population exhibited higher tumorigenic potential than the low-Zs population. The radioresistance of the high-Zs population of both HeLa and CaSki cells and the chemoresistance of the high-Zs population of CaSki cells were confirmed by a clonogenic survival assay and the tetrazolium dye assay, respectively. These results indicate that high-Zs populations of both the HeLa and CaSki cell lines possess CSC-like properties and therapeutic resistance. In conclusion, we successfully visualized CSC-like cells using a fluorescent protein system.
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Hayashi
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Tamari
authors.affiliation: Department of Cancer Profiling Discovery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Hideshi
authors.initials: H
authors.lastname: Ishii
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Konno
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Nishida
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kawamoto
authors.affiliation: Department of Cancer Profiling Discovery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Koseki
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Takahito
authors.initials: T
authors.lastname: Fukusumi
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kano
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Shimpei
authors.initials: S
authors.lastname: Nishikawa
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Miyo
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Noguchi
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Hisataka
authors.initials: H
authors.lastname: Ogawa
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hamabe
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Seo
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Doki
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ogawa
mesh_terms: D049109:Cell Proliferation / Q000235:genetics; D058948:Cell Tracking; D003952:Diagnostic Imaging / Q000379:methods*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D014411:Neoplastic Stem Cells / Q000473:pathology*; D046988:Proteasome Endopeptidase Complex / Q000302:isolation & purification; D018874:Spheroids, Cellular / Q000473:pathology; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000473:pathology
chemical_list: D049452:Green Fluorescent Proteins; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease