Gefitinib enhances arsenic trioxide (AS2O3)-induced differentiation of acute promyelocytic leukemia cell line

Gefitinib (Iressa, ZD1839), a selective epidermal growth factor receptor tyrosine kinase inhibitor, inhibits growth, invasion and colony formation of various cancer cells. However, little is known about the effect of combination of gefitinib and arsenic trioxide (ATO) on differentiation of acute promyelocytic leukemia (APL). Therefore, we investigated whether gefitinib had any role in the ATO-induced differentiation of NB4 cells (APL cell line). Gefitinib induced the expression of differentiation markers including CD11b and CD14 in ATO-treated NB4 cells and facilitated ATO-induced morphologic changes and ROS generation. The results were evident that the combination of gefitinib and ATO could induce more effectively the functional differentiation of leukemic cells to macrophage-like cells. Moreover, the ERK pathway was necessary for the enhancement of gefitinib in ATO-induced differentiation, measured by CD11b and CD14 expression on NB4 cells. Therefore, our data indicated that gefitinib can play a potential role as an adjunctive differentiation agent in APL.