Figure 4.

A function blocking antibody (Ab) to the INSR decreases self-renewal and proliferation of proneural GBM tumorspheres

(A) Representative images of proneural GBM tumorspheres grown in defined culture medium.

(B) Representative images of proneural GBM tumorspheres grown in defined medium with physiological concentrations of insulin but supplemented with IGF-II (LI + EGF + IGF-II).

(C) Representative images of proneural GBM tumorspheres grown in LI + EGF + IGF-II with a function blocking INSR Ab (IR Ab).

(D) Average number of tumorspheres/field ±SEM after 7 days of growth under different conditions (^∗∗∗p < 0.001, ^∗∗∗∗p < 0.0001).

(E) Average sizes of tumorspheres/field ±SEM after 7 days of growth under different conditions (^∗∗∗p < 0.001, ^∗∗∗∗p < 0.0001).

(F) Cell viability assay in proneural tumorspheres grown for 7 days in defined growth media (HI + EGF, LI + EGF + IGF-II, and LI + EGF + IGF-II + IR Ab) (p = not significant [n.s]).

(G) Extreme Limiting Dilution Assay (ELDA) performed on proneural tumorspheres grown for 21 days in vitro in the defined media conditions (HI + EGF, LI + EGF + IGF-II, and LI + EGF + IGF-II + IR Ab).

Data are representative of three independent experiments. Scale bars represent 50 μm. HI, high insulin; IR, INSR; LI, low insulin.