[Effects of cadmium on the gene expression of retinoblastoma (Y79) cells in culture].

We examined the effects of cadmium on the mRNA levels of several genes in cultured retinoblastoma (Y79) cells. After Y79 cells were treated with 15 microM CdCl2, RNA was extracted at a given time. The levels of retinoblastoma gene (Rb) mRNA decreased after cadmium treatment, although it was unlikely that the Rb gene product is functional in this cell line. The N-myc gene (oncogene) is constitutively expressed in untreated Y79 cells but its mRNA levels also decreased following cadmium treatment. On the other hand, the mRNA levels of both heat-shock protein (hsp 70) and metallothionein gene, both having physiological protective effects, increased under these conditions. These results indicate that Y79 cells have physiological protective responses to such a heavy metal as cadmium and that both Rb and N-myc gene expressions are down-modulated in the presence of cadmium.