Isolation and Characterization of CD44high K562 Cells

CD44^highK562 cells isolated from human K562 chronic myeloid leukemia cell line showed higher protein levels of stemness-related markers and ABC transporters compared with those of the parental K562 cells20 (link). CD44^highK562 cells maintained characteristics of cell morphology, cell proliferation ability, and high expression of stemness-related markers through serial culture until passage 15 after recovery from stocks. Human lymphoblastic leukemia multidrug-resistant (MDR) CEM/VLB₁₀₀ and MCF7-MDR (originally named MCF-7/Adr) cells were kindly provided by Dr. Fiedler (MD Anderson, Houston, TX, USA)21 (link). Cells were maintained in RPMI or DMEM medium (Invitrogen, Carlsbad, CA, USA) supplemented with 10% FBS and maintained at 37°C in humidified 5% CO₂ atmosphere. 17-Allylamino-17-demethoxygeldanamycin (17-AAG) was purchased from Enzo Life Sciences (Farmingdale, NY, USA). Celecoxib (CCB), ibuprofen (IBU), cycloheximide (CHX), 3-methyladenine (3-MA), chloroquine (CQ), 2,5-dimethyl-celecoxib (DMC), and rapamycin were purchased from Sigma-Aldrich (St. Louis, MO, USA). Z-DEVD-FMK was purchased from R&D Systems (Minneapolis, MN, USA). OSU-03012 was purchased from Selleckchem (Houston, TX, USA).