13cis- and all-trans Retinoic Acid have Antiproliferative Effects on CML Cells and Render IFN α Antiproliferative Potency after Combined Treatment in vitro

Abstract

The treatment of CML with IFNα is limited due to resistance against this substance. Recent studies with different cells than chronic myelogenous leukemic cells revealed a synergistic effect of a combined use of Retinoids (RA) and IFNα. The purpose of the study was to detect possible interactions of IFNα and RA in CML considering also the effect of the BCR-ABL gene-product. Therefore, we investigated three CML cell lines in their proliferation after incubation with IFNα and Retinoids alone and in combination. We measured low susceptibility to IFNα but a marked influence of the Retinoids. In combination, the growth inhibition was enhanced potentially in response to an increased efficacy of IFNα. Even solely, ineffective concentrations of both substances lead to decreased proliferation.