A, Expression of growth factors in tumors in comparison to
normal cerebelli. B, Expression levels of IGF1 and HGF, but not
PDGFA, were much higher in the tumor mass than in purified tumor GNPs (n=8).
C, HGF did not promote tumor cell proliferation.
D,E, IGF1 promoted cell proliferation of both mouse
(D) and human tumor cells (E). F,
Inactivation of IGF1R in GNPs delayed tumor progression (n≥12 for each
genotype). G, Inactivation of IGF1R in GNPs prolonged mouse
survival. While all IGF1R+/+ (n=7) and IGF1R−/+ (n=8) tumor mice died
before P90, all IGF1R-null mice (n=14) survived till the experimental endpoint
(P130). H, The medulloblastoma model in which IGF1R can be
inactivated after tumor onset. I, Tamoxifen (150 mg/kg) induced
inactivation of IGF1R in tumor GNPs suppressed tumor progression (n=8 for each
group).
Scale bar: F and I=1mm. Data are Means±SD, Student’s
t-test (C, D and E) or one-way ANOVA (F and I); n.s: not
significant,**p<0.01; ***p<0.001; ****p<0.0001.
See also Figure
S4