Effects of Cadmium Chloride on Neurite Outgrowth and Gene Expression in Human Neuroblastoma NB-1 Cells

Cadmium is a well-studied environmental toxi-cant. The neurotoxicity of cadmium is a concern, es-pecially in the developing human brain, because it is thought that cadmium exerts long-term and irrevers-ible effects. In the present study cadmium toxicity us-ing human neuroblastoma NB-1 cells was investigated in relation to gene expression and subsequent neurite extension using cDNA macroarray and image analysis techniques. The neurite outgrowth in NB-1 cells was stimulated significantly by the presence of dibutyryl-cyclicAMP (db-cAMP) and by cadmium chloride at sublethal concentrations. Db-cAMP-stimulated neurite outgrowth was associated with a three-fold increased expression of axonal membrane protein growth-asso-ciated protein-43 (GAP-43), but cadmium chloride did not affect GAP-43 expression. Db-cAMP also increased dopamine β-hydroxylase gene expression eight-fold and down-regulated muscle/brain cAMP-dependent pro-tein kinase inhibitor gene expression. However, cad-mium chloride had no effect on gene expression ex-cept for that of metallothionein II (mtII) gene among 1764 genes analyzed. The results demonstrate that the increased neurite outgrowth with cadmium chloride is not associated with the same gene expression profile of that with db-cAMP. Key words —– — human neuroblastoma cell, neurite ex-tension, cadmium chloride, cDNA macroarra