Inositol derivatives down-regulate c-myc inducing growth arrest without differentiation.

Cyclitol derivatives that are structurally related to myo-inositol induce growth arrest without differentiation in human promyelocytic leukemia (HL60) cells. An early effect is the rapid down-regulation of c-myc mRNA levels. This was observed also in several mouse and human lines carrying either normal or rearranged myc. The mRNA levels of a constitutive mouse myc construct transfected into HL60 were not affected at the same time. Uridine and thymidine incorporation were significantly decreased by the cyclitol treatment. These effects partly resemble those of certain differentiation inducers and those of hexachlorcyclohexane, another myo-inositol analogue. This new group of agents offers a novel approach to studying control mechanisms involving c-myc.