title: Synergistic cytotoxic effects of bortezomib and CK2 inhibitor CX-4945 in acute lymphoblastic leukemia: turning off the prosurvival ER chaperone BIP/Grp78 and turning on the pro-apoptotic NF-κB.
abstract: The proteasome inhibitor bortezomib is a new targeted treatment option for refractory or relapsed acute lymphoblastic leukemia (ALL) patients. However, a limited efficacy of bortezomib alone has been reported. A terminal pro-apoptotic endoplasmic reticulum (ER) stress/unfolded protein response (UPR) is one of the several mechanisms of bortezomib-induced apoptosis. Recently, it has been documented that UPR disruption could be considered a selective anti-leukemia therapy. CX-4945, a potent casein kinase (CK) 2 inhibitor, has been found to induce apoptotic cell death in T-ALL preclinical models, via perturbation of ER/UPR pathway. In this study, we analyzed in T- and B-ALL preclinical settings, the molecular mechanisms of synergistic apoptotic effects observed after bortezomib/CX-4945 combined treatment. We demonstrated that, adding CX-4945 after bortezomib treatment, prevented leukemic cells from engaging a functional UPR in order to buffer the bortezomib-mediated proteotoxic stress in ER lumen. We documented that the combined treatment decreased pro-survival ER chaperon BIP/Grp78 expression, via reduction of chaperoning activity of Hsp90. Bortezomib/CX-4945 treatment inhibited NF-κB signaling in T-ALL cell lines and primary cells from T-ALL patients, but, intriguingly, in B-ALL cells the drug combination activated NF-κB p65 pro-apoptotic functions. In fact in B-cells, the combined treatment induced p65-HDAC1 association with consequent repression of the anti-apoptotic target genes, Bcl-xL and XIAP. Exposure to NEMO (IKKγ)-binding domain inhibitor peptide reduced the cytotoxic effects of bortezomib/CX-4945 treatment. Overall, our findings demonstrated that CK2 inhibition could be useful in combination with bortezomib as a novel therapeutic strategy in both T- and B-ALL.
authors.affiliation: Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Buontempo
authors.affiliation: Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
authors.forename: Ester
authors.initials: E
authors.lastname: Orsini
authors.affiliation: Pediatric Oncology and Hematology Unit "Lalla Seràgnoli", S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Lonetti
authors.affiliation: Department of Human Social and Health Sciences, Campus Folcara, University of Cassino, Cassino, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cappellini
authors.affiliation: Muscoloskeletal Cell Biology Laboratory, IOR, Bologna, Italy.|Institute of Molecular Genetics, National Research Council-Rizzoli Orthopedic Institute, Bologna, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Chiarini
authors.affiliation: Muscoloskeletal Cell Biology Laboratory, IOR, Bologna, Italy.|Institute of Molecular Genetics, National Research Council-Rizzoli Orthopedic Institute, Bologna, Italy.
authors.forename: Camilla
authors.initials: C
authors.lastname: Evangelisti
authors.affiliation: Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Evangelisti
authors.affiliation: Pediatric Oncology and Hematology Unit "Lalla Seràgnoli", S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
authors.forename: Fraia
authors.initials: F
authors.lastname: Melchionda
authors.affiliation: Pediatric Oncology and Hematology Unit "Lalla Seràgnoli", S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Pession
authors.affiliation: Department of Pediatric Hematology and Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.
authors.forename: Alice
authors.initials: A
authors.lastname: Bertaina
authors.affiliation: Department of Pediatric Hematology and Oncology, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Locatelli
authors.affiliation: Department of Surgery, Medicine, Odontostomatology and Morphological Sciences, University of Modena, Modena, Italy.
authors.forename: Jessika
authors.initials: J
authors.lastname: Bertacchini
authors.affiliation: Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy.
authors.forename: Luca Maria
authors.initials: LM
authors.lastname: Neri
authors.affiliation: Department of Microbiology and Immunology, School of Medicine, East Carolina University, Greenville, NC, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: McCubrey
authors.affiliation: Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
authors.forename: Alberto Maria
authors.initials: AM
authors.lastname: Martelli
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D000069286:Bortezomib / Q000494:pharmacology*; D047390:Casein Kinase II / Q000037:antagonists & inhibitors; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004357:Drug Synergism; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D019169:Jurkat Cells; D008856:Microscopy, Fluorescence; D009287:Naphthyridines / Q000494:pharmacology*; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism; D010619:Phenazines; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood / Q000473:pathology; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood / Q000473:pathology; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood / Q000473:pathology; D051996:Transcription Factor RelA / Q000378:metabolism*; D056811:Unfolded Protein Response / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D009287:Naphthyridines; D010619:Phenazines; D051996:Transcription Factor RelA; D000069286:Bortezomib; C555142:silmitasertib; D047390:Casein Kinase II
keywords: BIP/Grp78; CK2; NF-κB; acute lymphoblastic leukemia; unfolded protein response