mdr 1 gene-expression and villin synthesis in a colon cancer cell line differentiated by sodium butyrate.

Sodium butyrate (NaBu) but not dimethylsulfoxide (DMSO) induced the synthesis of villin, a protein of the brush border microvilli cytoskeleton, in a rat colon cancer cell line. Neither NaBu nor DMSO altered mdr 1-mRNA expression or multidrug resistance (MDR)--associated cellular transport of doxorubicin. These results show that mdr 1 gene expression and activity are independent of other brush border proteins induced by differentiating agents at the apical pole of the epithelial cell.