title: B7-H4 expression is elevated in human U251 glioma stem-like cells and is inducible in monocytes cultured with U251 stem-like cell conditioned medium.
abstract: Previous studies indicated that B7-H4, the youngest B7 family, negatively regulates T cell-mediated immunity and is significantly overexpressed in many human tumors. Tumor stem cells are purported to play a role in tumor renewal and resistance to radiation and chemotherapy. However, the link between B7-H4 and tumor stem cells is unclear. In this study, we investigated B7-H4 expression in the medium of human glioma U251 cell cultures. Immunofluorescence results showed that U251 cells cultured in serum-free medium (supplemented with 2% B27, 20 ng/mL epidermal growth factor, 20 ng/mL basic fibroblast growth factor) maintained stem-like cell characteristics, including expression of stem cell marker CD133 and the neural progenitor cell markers nestin and SOX2. In contrast, U251 cells cultured in serum-containing medium highly expressed differentiation marker glial fibrillary acidic protein. Flow cytometry analysis showed serum-free medium-cultured U251 cells expressed higher intracellular B7-H4 than serum-containing medium-cultured U251 cells (24%-35% vs. 8%-11%, P < 0.001). Immunofluorescence in purified monocytes from normal human peripheral blood mononuclear cells revealed moderate expression of B7-H4 after stimulation with conditioned medium from U251 cells cultured in serum-containing medium. Moreover, conditioned medium from U251 stem-like cells had a significant stimulation effect on B7-H4 expression compared with serum-containing conditioned medium (P < 0.01). Negative costimulatory molecule B7-H4 was preferentially expressed in U251 stem-like cells, and conditioned medium from these cells more effectively induced monocytes to express B7-H4 than conditioned medium from U251 cells cultured in the presence of serum. Our results show that U251 stem-like cells may play a more crucial role in tumor immunoloregulation with high expression of B7-H4.
authors: Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310009, P. R. China. zjm135@vip.sina.com, yu_yao@fudan.edu.cn.
authors: Lian-Jie
authors: LJ
authors: Mo
authors: Hong-Xing
authors: HX
authors: Ye
authors: Ying
authors: Y
authors: Mao
authors: Yu
authors: Y
authors: Yao
authors: Jian-Min
authors: JM
authors: Zhang
mesh_terms: D000071916:AC133 Antigen; D015703:Antigens, CD / Q000378:metabolism; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; D015972:Gene Expression Regulation, Neoplastic; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D009000:Monocytes / Q000166:cytology / Q000378:metabolism*; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D064231:Nestin / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D055748:SOXB1 Transcription Factors / Q000378:metabolism; D060907:V-Set Domain-Containing T-Cell Activation Inhibitor 1 / Q000378:metabolism*
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; D005904:Glial Fibrillary Acidic Protein; D006023:Glycoproteins; C577484:NES protein, human; D064231:Nestin; C000606023:PROM1 protein, human; D010455:Peptides; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors; D060907:V-Set Domain-Containing T-Cell Activation Inhibitor 1; C475826:VTCN1 protein, human