title: HDAC inhibitors induce apoptosis in glucocorticoid-resistant acute lymphatic leukemia cells despite a switch from the extrinsic to the intrinsic death pathway.
abstract: Inhibitors of histone deacetylases (HDACi's) are promising novel tools for cancer therapy. We have compared the growth inhibitory and apoptogenic potential of the pan-HDACi SAHA and the sub-class I selective HDAC inhibitor MS275, as well as valproic acid (VPA) on glucocorticoid sensitive and resistant B (B-ALL) and T (T-ALL) cell acute lymphoblastic leukemia cells and patients blasts. In contrast, to our previous results with U937 acute myeloid leukemia (AML) cells which showed a similar activity of MS275 and SAHA in growth inhibition and apoptosis induction, both B and T-ALL cells were much more efficiently killed by SAHA and VPA than by MS275. The same relative potency was observed with some patient ALL blasts treated ex vivo. SAHA displayed similar efficacy on glucocorticoid-sensitive and insensitive ALL cells but did not synergize with dexamethasone. In studying mediators of apoptosis we found that the TRAIL receptor DR5 is constitutively expressed in glucocorticoid-sensitive CEM-C7 cells which are also TRAIL sensitive. In contrast, glucocorticoid-insensitive CEM-C1 cells do not express DR5 and are insensitive to TRAIL. However, SAHA induces, in addition to p21(WAF1/CIP1) also re-expression of DR5. Importantly, SAHA-induced apoptosis of CEM-C7 cells operates through initiator caspase 10, while it induces apoptosis of CEM-C1 cells through the intrinsic, as well as through caspase-independent death pathways. Our data suggest that the generation of resistance to glucocorticoids has dramatically altered death signaling in these cells and that SAHA overcomes these restrictions by inducing alternative death pathways.
authors.affiliation: Department of Cell Biology and Signal Transduction, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC)/CNRS/INSERM/ULP, BP 10142, F-67404 Illkirch Cedex, C.U. de Strasbourg, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Tsapis
authors.forename: Michèle
authors.initials: M
authors.lastname: Lieb
authors.forename: Fabio
authors.initials: F
authors.lastname: Manzo
authors.forename: Pattabhiraman
authors.initials: P
authors.lastname: Shankaranarayanan
authors.forename: Raoul
authors.initials: R
authors.lastname: Herbrecht
authors.forename: Patrick
authors.initials: P
authors.lastname: Lutz
authors.forename: Hinrich
authors.initials: H
authors.lastname: Gronemeyer
mesh_terms: D017209:Apoptosis; D001549:Benzamides / Q000494:pharmacology* / Q000627:therapeutic use; D002051:Burkitt Lymphoma / Q000473:pathology*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D005938:Glucocorticoids / Q000494:pharmacology*; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology*; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000473:pathology*; D011725:Pyridines / Q000494:pharmacology* / Q000627:therapeutic use; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D014635:Valproic Acid / Q000494:pharmacology; D000077337:Vorinostat
chemical_list: D001549:Benzamides; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D005938:Glucocorticoids; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D011725:Pyridines; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; C118739:entinostat; D000077337:Vorinostat; D014635:Valproic Acid; D003907:Dexamethasone; D006655:Histone Deacetylases