Fig. 6
Stabilized glioblastoma cell lines in standard 10% serum monolayer conditions are characterized by a fraction of SA-β-Gal (+) cells. Comparison of A9 cell line in early 3rd (a) and late 8th passage (b). Representative picture showing senescent cells in commercially available cell line U87-MG (c). Comparison of spontaneous in vitro senescence in primary glioblastoma cultures stabilized in our department (A9, GB10) and commercially available GB stable cancer cell lines (d). The average percentage was obtained by analyzing of at least 200 cells per case from indicated passages (A9, GB7) or for stable GB lines (DK-MG, U87-MG and T98G). The number of SA-β-Gal (+) cells statistically differs for A9 line between passage 3 and passage 8 as well as for GB7 line between passage 3 and passage 17 (p < 0.05). Error bars indicate SEM. Statistical significance calculated by paired Student’s t-test. *, p < 0.05; **, p < 0.01; ***, p < 0.005