Background: MASH1, a transcription factor with basic helix-loop-helix domain, has a pivotal function to promote differentiation of neural crest cells into autonomic neurons.
Procedure: To investigate the functional significance of human MASH1 (hASH1) in the pathogenesis of neuroblastoma, which is originated from autonomic precursor cells, we studied hASH1 gene expression in primary neuroblastomas and human nueroblastoma cell lines.
Results: The follovving results were obtained: (i) hASH1 was expressed in 40 out of 61 (66%) primary neuroblastomas, (ii) hASH1 transcripts were downregulated in several cell lines prior to differentiation induced by all-trans retinoic acid (RA), (iii) a neuroblasotma cell line without expression of endogenous hASH1 did not respond to RA at all, and (iv) the analysis of the hASH1 genomic DNA revealed two possible transcription initiation sites, which may correspond to 3.0 kb and 3.5 kb transcripts.
Conclusions: Our observations suggest that, although hASH1 may not preserve the growth capacity of neuroblastomas, downregulation of hASH1 may be necessary to promote neuronal differentiation of neuroblastoma.