Regulation of glutamine transport by the type I insulin-like growth factor receptor in a human neuroblastoma cell line

We examined the effects of the monoclonal antibody against the type I insulin-like growth factor receptor (IGF-IR), αIR3, on cell growth and membrane glutamine (Gln) transport in a human neuroblastoma cell line, SK-N-SH. In the presence of αIR3 (2 μg/ml), the cell proliferation rate was significantly attenuated. Gln transport was decreased in the αIR3-treated group with the mechanism of decreasing maximum transport velocity without affecting transport affinity. The addition of αIR3 significantly decreased DNA and protein biosynthesis. Our results support the concept that the activation of IGF-IR partially mediates neuroblastoma cell proliferation by regulating membrane Gln transport.