Slug promotes glioblastoma growth and decreases survival in vivo. A) Human U251 glioblastoma cells transduced with a Slug-IRES-EGFP lentivirus or a control lentivirus were implanted subcutaneously into the flanks of nude mice. Quantitative data on tumor growth is shown on the right. Data shown are mean ± SEM (n = 4). Tumors overexpressing Slug grew at a faster rate than control tumors (P < 0.007 at 4 weeks, t-test). B) Histological characteristics of U251 glioblastoma tumors shown in A). Sections are stained with hematoxylin and eosin. Note the spindle morphology of the Slug-overexpressing tumors. C) CD31 immunoreactivity in U251 glioblastoma tumors overexpressing Slug or a control vector. Increased CD31 immunoreactivity was observed in Slug-overexpressing tumors, indicating the presence of increased vascularity (P < 0.002, t-test). D) upper panel mRNA microarray data obtained from human U251 glioblastoma cells transduced with either an SNAI2 lentivirus or a control virus. Data are expressed as fold change relative to mRNA expression in control cells. lower panels IL8 mRNA expression after Slug overexpression or Slug knockdown was validated by Real-time PCR in U251-IRES-Slug and U87-ShSlug glioblastma cells, respectively. Data shown are mean ± SEM of three replicates. E) Regression plot of SNAI2 mRNA versus VEGF mRNA expression. mRNA microarray data was obtained from 20 human glioblastomas. R
2 = 0.068. F) U87 human glioblastoma cells transduced with a Slug shRNA lentivirus or a control virus were transplanted into the brains of nude mice. Kaplan-Meier survival analysis indicated that SNAI2/Slug knockdown significantly improved survival (P < 0.0012, Logrank test).