SMPD1 and neuroblastoma: Manumycine is an anti-bacterial agent which inhibits the small GTPases Ras enzyme in F11, mouse neuroblastoma hybrid cells, and rat dorsal root ganglion cells [26], and imipramine is a tri-cyclic anti-depressant which inhibits the acid sphingomyelinase (aSMase) both in vitro and in vivo [27,28].