GDNF and neuroblastoma: GDNF is known to promote the survival and morphological differentiation of dopaminergic neurons.30,31 To determine whether GDNF derived from 3D-BMSCs promotes the differentiation of dopaminergic neurons, we performed coculture experiments with 3D-BMSCs and TGW, a human neuroblastoma cell line17 (Fig. 5C).