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...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-H4and 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 serumcontaining 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-H4expression 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.展开更多
基金supported by grants from the National Natural Science Foundation of China (No.81272797 to Y.Y.)nnovation Program of Shanghai Municipal Education Commission (No.13ZZ010 to Y.Y.)Shanghai Talents Development Funds (No.2011063 to Y.Y.)
文摘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-H4and 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 serumcontaining 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-H4expression 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.
