Medulloblastoma is the most common malignant
tumor of the central nervous system in children. The
insulin-like growth factor-I receptor (IGF-IR) is an important
growth factor for
medulloblastoma. The novel
IGF-I receptor (IGF-IR)
kinase inhibitor
NVP-ADW742 has in vitro activity against
tumors. Daoy cells were treated with
NVP-ADW742 combined with
temozolomide, which is commonly used in the
chemotherapy of
medulloblastoma. The effects on proliferation were assayed by
CCK-8 assay. Cell cycle status and apoptosis were assayed by FACS analysis. The IGF-IR signaling pathway was analyzed by RT2 Profiler™ PCR arrays and Western blotting.
NVP-ADW742 inhibited IGF-IR-mediated proliferation with an IC50 of 11.12 µmol/l. The PCR array data suggested that 14 genes were down-regulated at the
mRNA level after
NVP-ADW742 treatment. Western blot analysis suggested that
NVP-ADW742 induced early suppression of Akt, P38 and GSK-3β phosphorylation, as well as a decrease in the intracellular levels of PI3K, Akt, P38, GSK-3β and Bcl-2. Combined with
NVP-ADW742 (2 µmol/l), IC50 of Daoy to
temozolomide was decreased from 452.12 to 256.81 µmol/l. Cell apoptosis was enhanced from 16.18±2.47% to 23.20 ± 2.80%. G phase arrest was also found in both the
temozolomide alone group and the
temozolomide combined with
NVP-ADW742 group.
NVP-ADW742 inhibited the activation of PI3K, Akt, P38 and GSK-3β caused by
temozolomide.
NVP-ADW742 enhanced the chemosensitivity of Daoy to
temozolomide in vitro, as a potent anti-
tumor agent highly selective against IGF-IR.