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Leukemia Research Jun 2011Activation of the TNF-related apoptosis-inducing ligand (TRAIL) pathway can induce apoptosis in a broad range of human cancer cells. Four membrane-bound receptors have...
Activation of the TNF-related apoptosis-inducing ligand (TRAIL) pathway can induce apoptosis in a broad range of human cancer cells. Four membrane-bound receptors have been identified. TRAIL-R1 and TRAIL-R2 contain a functional death domain; TRAIL-R3 and TRAIL-R4 lack a functional death domain and function as decoy receptors. Flow-cytometric analysis revealed that acute myeloid leukemic (AML) blasts expressed significantly more pro-apoptotic receptors compared to normal blasts. However, about 20% of AML patients highly expressed decoy receptor TRAIL-R3, which was strongly correlated to a shortened overall survival. TRAIL-R3 expression was also high on CD34+/CD38- cells, the compartment that harbors the leukemia initiating stem cell. Expression levels of pro-apoptotic TRAIL receptors were not correlated to the susceptibility for soluble TRAIL, which was generally low (mean level of cell death induction 14%). Cell death could be enhanced by down-modulation of TRAIL-R3, confirming its decoy function on AML blasts. Bypassing of TRAIL-R3 by treatment with antibodies directly targeting TRAIL-R2 resulted in higher rates of induced cell death (max. 80%). In conclusion, AML blasts do express pro-apoptotic TRAIL receptors. However, co-expression of decoy receptor TRAIL-R3 results in significant shortened overall survival. AML blasts could be targeted by anti-TRAIL-R2 antibodies, yielding a new therapeutic option for AML patients.
Topics: Adolescent; Adult; Aged; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Apoptosis; Bone Marrow Cells; Cell Line; Cell Line, Tumor; Drug Resistance, Neoplasm; Female; GPI-Linked Proteins; HL-60 Cells; Humans; Kaplan-Meier Estimate; Leukemia, Myeloid, Acute; Male; Middle Aged; Neoplastic Stem Cells; Prognosis; Receptors, TNF-Related Apoptosis-Inducing Ligand; Receptors, Tumor Necrosis Factor, Member 10c; TNF-Related Apoptosis-Inducing Ligand; Treatment Outcome; Tumor Necrosis Factor Decoy Receptors; U937 Cells; Young Adult
PubMed: 21281967
DOI: 10.1016/j.leukres.2010.12.032