Macrophage-like THP-1 Cells Derived from High-Density Cell Culture Are Resistant to TRAIL-Induced Cell Death via Down-Regulation of Death-Receptors DR4 and DR5

Abstract

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) is a highly selective and promising anticancer agent due to its specific apoptosis-inducing effect on tumor cells, rather than most normal cells. TRAIL is currently under investigation for use in the treatment of leukemia. However, the resistance of leukemic cells to TRAIL-induced apoptosis may limit its efficacy. The mechanisms of leukemic cell resistance to antitumor immunity remains a topical issue. In this work, we have found an increase in the resistance to TRAIL-induced cell death in human leukemia THP-1 cells, which was caused by differentiation into a macrophage-like phenotype in high-density culture in vitro. Stressful conditions, manifested by the inhibition of cell growth and the activation of cell death in high-density culture of THP-1 cells, induced the appearance of cells adhered to culture dishes. The THP-1ad cell line was derived by selection of these adhered cells. The genetic study, using STR and aCGH assays, has shown that THP-1ad cells were derived from THP-1 cells due to mutagenesis. The THP-1ad cells possessed high proliferative potential and a macrophage-like immunophenotype. The adhesion of THP-1ad cells to the extracellular matrix was mediated by αVβ5 integrin. The cytokine production, as well as the rise of intracellular ROS and NO activities by LPS in THP-1ad cell culture, were characteristic of macrophage-like cells. The THP-1ad cells were found to appear to increase in resistance to TRAIL-induced cell death in comparison with THP-1 cells. The mechanism of the increase in TRAIL-resistance can be related to a decrease in the expression of death receptors DR4 and DR5 on the THP-1ad cells. Thus, the macrophage-like phenotype formation with the maintenance of a high proliferative potential of leukemic cells, caused by stress conditions in high-density cell cultures in vitro, can induce an increase in resistance to TRAIL-induced cell death due to the loss of DR4 and DR5 receptors. The possible realization of these events in vivo may be the reason for tumor progression.

Targeted Diagnosis, Therapeutic Monitoring, and Assessment of Atherosclerosis Based on Mesoporous Silica Nanoparticles Coated with cRGD-Platelets

“…THP-1 cells were ordered from the Global Bioresource Center (ATCC, USA), cultured in RPMI 1640 supplemented with 100 U/mL penicillin, fetal bovine serum (10%), and 100 μ g/mL streptomycin and placed in a humidified chamber (5% CO 2 at 37°C). The THP-1 cells were differentiated into macrophages by adding 100 ng/mL PMA for 72 h. The macrophages were transformed into foam cells by incubating for 48 h with 50 μ g/mL oxLDL in serum-free RPMI 1640 medium containing 0.3% BSA [ 20 ].…”

The Increase in the Drug Resistance of Acute Myeloid Leukemia THP-1 Cells in High-Density Cell Culture Is Associated with Inflammatory-like Activation and Anti-Apoptotic Bcl-2 Proteins

“…The staining was carried out at room temperature in the dark for 30 min. After staining, the cells were fixed with 2% paraformaldehyde solution and an analysis of CD expression was performed using a BD Accuri C6 flow cytometer (BD Bioscience, Franklin Lakes, NJ, USA) [ 75 ].…”

“…Cell viability was assessed after staining them in suspension in culture medium with 200 nM of Calcein AM fluorescent dyes and 1 μg /mL of propidium iodide [ 76 ]. Cell proliferation was also assessed by DNA cytograms in cell populations and the expression of the Ki-67 nuclear antigen using the flow cytometer, and by the percent of mitotic cells [ 75 ]. To analyze DNA histograms, the cells were suspended in phosphate-buffered saline, fixed with 70% ethanol, and stained with 1 μg/mL of propidium iodide.…”

“…The cell cycle was analyzed using ModFit LT 4.1 software (Topsham, ME, USA). Mitotic cells were evaluated by the fluorescence of cells that were stained with nuclear dyes H 33342 at a concentration of 1 μg/mL and counting the number of mitotic cells using a DM 6000 fluorescence microscope (Leica, Wetzlar, Germany) [ 75 ]. The total number of cells that were analyzed in randomly selected fields was at least 500.…”

“…To study the inducible NO production, the cells were preincubated with 10 μg/mL of LPS from E. coli O111: B4 for 24 h. All the incubation procedures were performed in a CO 2 -incubator. Cell fluorescence was analyzed using a BD Accuri C6 flow cytometer [ 75 ].…”