title: Spheroid body-forming cells in the human gastric cancer cell line MKN-45             possess cancer stem cell properties.
abstract: The cancer stem cell theory hypothesizes that cancer stem cells (CSCs),             which possess self-renewal and other stem cell properties, are regarded as the             cause of tumor formation, recurrence and metastasis. The isolation and identification             of CSCs could help to develop novel therapeutic strategies specifically targeting             CSCs. In this study, we enriched gastric cancer stem cells through spheroid body             formation by cultivating the human gastric cancer cell line MKN-45 in defined             serum-free medium. The stemness characteristics of spheroid body-forming cells,             including self-renewal, proliferation, chemoresistance, tumorigenicity of the             MKN-45 spheroid body-forming cells were evaluated, and the expression levels of             stemness genes and related proteins in the MKN-45 spheroid body-forming cells             were assessed. Furthermore, immunofluorescence staining for the stem cell markers             on spheroid body-forming cells was examined to evaluate the association between             stemness factors (Oct4, Sox2, Nanog) and the proposed CSC marker CD44. Our data             demonstrated that non-adherent spheroid body-forming cells from the gastric cancer             cell line MKN-45 cultured in stem cell-conditioned medium possessed gastric CSC             properties, such as persistent self-renewal, extensive proliferation, drug resistance,             high tumorigenic capacity and overexpression of CSC-related genes and proteins             (Oct4, Sox2, Nanog and CD44), compared with the parental cells. More importantly,             CD44-positive cells co-expressing the pluripotency genes Oct4, Sox2 and Nanog             may represent gastric CSCs. Further experiments using more refined selection criteria             such as a combination of two or multiple markers would be useful to specifically             identify and purify CSCs.
authors.affiliation: Department of General Surgery, Affiliated Hospital, Nantong University,                     Nantong 226001, Jiangsu Province, P.R. China.
authors.forename: Jianming
authors.initials: J
authors.lastname: Liu
authors.forename: Lilin
authors.initials: L
authors.lastname: Ma
authors.forename: Junfei
authors.initials: J
authors.lastname: Xu
authors.forename: Chun
authors.initials: C
authors.lastname: Liu
authors.forename: Jianguo
authors.initials: J
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Ruixin
authors.initials: R
authors.lastname: Chen
authors.forename: Youlang
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D018398:Homeodomain Proteins / Q000096:biosynthesis; D006801:Humans; D000071317:Nanog Homeobox Protein; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology*; D050814:Octamer Transcription Factor-3 / Q000096:biosynthesis; D039904:Pluripotent Stem Cells / Q000473:pathology*; D055748:SOXB1 Transcription Factors / Q000096:biosynthesis; D018874:Spheroids, Cellular / Q000378:metabolism / Q000473:pathology*; D013274:Stomach Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: D018398:Homeodomain Proteins; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors