Neuroblastoma Growth Factors Derived from Neurofibroma (NF1): Participation of Uridine in a Neuroblastoma Growth

: Human glioma cell extracts were found to elicit a marked growth‐promoting activity on human neuroblastoma cells. This activity was also detected in the extracts of neurofibroma type 1 (NF1; von Recklinghausen neurofibromatosis) comprising aberrant Schwann cell growth. The purified substance from the NF1 extracts by HPLC on ODS columns was identical to a pyrimidine nucleoside, uridine, the chemical structure of which was identified by gas chromatography‐mass spectrometry. The authentic uridine showed a strong growth‐promoting activity on human neuroblastoma cells. Other purine or pyrimidine nucleotides, their derivatives, and ribose sources for their syntheses were employed to test the activity; a purine nucleoside, adenosine, showed a stronger activity than uridine. The current study raises the possibility that human neuroblastoma cells may be affected by dysfunctions of the de novo pathway of both purine and pyrimidine nucleotide biosyntheses.