Induction of Multidrug Resistance of Acute Myeloid Leukemia Cells by Cocultured Stromal Cells via Upregulation of the PI3K/Akt Signaling Pathway

This study aimed to investigate the role of the PI3K/Akt signaling pathway in multidrug resistance of acute myeloid leukemia (AML) cells induced by cocultured stromal cells. Human AML cell lines HL-60 and U937 were adhesion cocultured with human bone marrow stromal cell line HS-5 cells. Such coculturing induced HL-60 and U937 cells resistant to chemotherapeutic drugs including daunorubicin (DNR), homoharringtonine (HHT), and cytosine arabinoside (Ara-C). The coculturing-induced resistance of AML cells to DNR, HHT, and Ara-C can be partially reversed by inhibition of the PI3K/Akt signaling pathway. Clinically, AML patients with a low level of PTEN and a high level of CCND1 had high relapse rates within 1 year, and newly diagnosed AML patients with extramedullary infiltration had a low level of PTEN. This study confirms the involvement of the PI3K/Akt signaling pathway in multidrug resistance in AML cells induced by stroma and suggests that the expression of PTEN and CCND1 may be a prognostic indicator for AML.