Phenotype of SHG-44 glioma stem cell spheres and pathological characteristics of their xenograft tumors

Abstract

To study the phenotype and tumorigenicity of SHG-44 glioma stem cell spheres and the pathological characteristics of their xenograft tumors. SHG-44 glioma cells were cultured under neural stem cell medium and glioma stem cell spheres were collected. Immunocytochemistry was used to dectet the expression of CD133, nestin, A2B5, vimentin, VEGFR-2 and IDH R132H. Cell spheres were induced using serum-containing medium, and the expression of CD133, nestin, vimentin, GFAP, β-III tubulin and GalC in the cell spheres were detected. The expression of CD133, nestin, VEGFR-2, GFAP, S-100 and CD34 in the intracranial xenograft tumor tissues was detected using immunohistochemistry. The pathological characteristics of orthotopic xenograft tumors generated from the SHG-44 glioma cells and SHG-44 glioma stem cell spheres were compared. SHG-44 glioma stem cell spheres were collected successfully after cultured under neural stem cell medium. The ratio of CD133(+) cells in the passage 10 SHG-44 glioma stem cell spheres was (71.63 ± 5.92)%, significantly higher than that in the SHG-44 glioma cells [(1.95 ± 1.45)%]. Immunocytochemistry showed that in the SHG-44 glioma cell spheres, the ratio of nestin(+) cells was (84.06 ± 7.58)%, vimentin(+) cells (29.11 ± 3.44)%, VEGFR 2(+) cells (64.44 ± 3.69)%, and A2B5(+) cells (14.08 ± 2.19)%. A subpopulation of cells with mutation of IDH R132H was detected harboring in the SHG-44 glioma cell spheres. After induction of differentiation with serum-containing medium, the ratio of CD133(+) cells was (1.89 ± 1.27)%, nestin(+) cells (6.67 ± 2.75)%, vimentin(+) cells (93.75 ± 2.95)%, GFAP (+) cells (91.33 ± 4.75)%, β-III tubulin(+) cells (82.36 ± 4.02)%, and GalC(+) cells (8.92 ± 3.19)%. Immunohistochemistry showed positive expression of GFAP, S-100, VEGFR-2, and negative of CD133 and nestin in the orthotopic xenograft tumors. A very small amount of human-specific CD34 cells formed a tubular structure. Compared with the SHG-44 glioma cell-formed xenograft tumor, the SHG-44 glioma stem cell-formed xenograft tumor exhibited a higher local invasiveness. SHG-44 glioma cell spheres are successfully collected after cultured under neural stem cell medium. They belong to the CD133(+)A2B5(-) GSC subpopulation, highly expressing VEGFR-2, possess the ability of both self-renewal and multi-directional differentiation, and may participate in the formation of vasculogenic mimicry.