title: Cytotoxic synergy between the multikinase inhibitor sorafenib and the proteasome inhibitor bortezomib in vitro: induction of apoptosis through Akt and c-Jun NH2-terminal kinase pathways.
abstract: This study was undertaken to characterize preclinical cytotoxic interactions for human malignancies between the multikinase inhibitor sorafenib (BAY 43-9006) and proteasome inhibitors bortezomib or MG132. Multiple tumor cell lines of varying histiotypes, including A549 (lung adenocarcinoma), 786-O (renal cell carcinoma), HeLa (cervical carcinoma), MDA-MB-231 (breast), K562 (chronic myelogenous leukemia), Jurkat (acute T-cell leukemia), MEC-2 (B-chronic lymphocytic leukemia), and U251 and D37 (glioma), as well as cells derived from primary human glioma tumors that are likely a more clinically relevant model were treated with sorafenib or bortezomib alone or in combination. Sorafenib and bortezomib synergistically induced a marked increase in mitochondrial injury and apoptosis, reflected by cytochrome c release, caspase-3 cleavage, and poly(ADP-ribose) polymerase degradation in a broad range of solid tumor and leukemia cell lines. These findings were accompanied by several biochemical changes, including decreased phosphorylation of vascular endothelial growth factor receptor-2, platelet-derived growth factor receptor-beta, and Akt and increased phosphorylation of stress-related c-Jun NH2-terminal kinase (JNK). Inhibition of Akt was required for synergism, as a constitutively active Akt protected cells against apoptosis induced by the combination. Alternatively, the JNK inhibitor SP600125 could also protect cells from apoptosis induced by the combination, indicating that both inhibition of Akt and activation of JNK were required for the synergism. These findings show that sorafenib interacts synergistically with bortezomib to induce apoptosis in a broad spectrum of neoplastic cell lines and show an important role for the Akt and JNK pathways in mediating synergism. Further clinical development of this combination seems warranted.
authors.affiliation: Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Chunrong
authors.initials: C
authors.lastname: Yu
authors.forename: Bret B
authors.initials: BB
authors.lastname: Friday
authors.forename: Jin-Ping
authors.initials: JP
authors.lastname: Lai
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.forename: Jann
authors.initials: J
authors.lastname: Sarkaria
authors.forename: Neil E
authors.initials: NE
authors.lastname: Kay
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Carter
authors.forename: Lewis R
authors.initials: LR
authors.lastname: Roberts
authors.forename: Scott H
authors.initials: SH
authors.lastname: Kaufmann
authors.forename: Alex A
authors.initials: AA
authors.lastname: Adjei
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001557:Benzenesulfonates / Q000494:pharmacology*; D001897:Boronic Acids / Q000494:pharmacology*; D000069286:Bortezomib; D045744:Cell Line, Tumor; D004357:Drug Synergism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D019169:Jurkat Cells; D020014:K562 Cells; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009536:Niacinamide / Q000031:analogs & derivatives; D051058:Oncogene Protein v-akt / Q000378:metabolism*; D010671:Phenylurea Compounds; D011480:Protease Inhibitors / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors; D011719:Pyrazines / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D000077157:Sorafenib
chemical_list: D000970:Antineoplastic Agents; D001557:Benzenesulfonates; D001897:Boronic Acids; D010671:Phenylurea Compounds; D011480:Protease Inhibitors; D061988:Proteasome Inhibitors; D011719:Pyrazines; D011725:Pyridines; D009536:Niacinamide; D000069286:Bortezomib; D000077157:Sorafenib; D051058:Oncogene Protein v-akt; D048031:JNK Mitogen-Activated Protein Kinases; D046988:Proteasome Endopeptidase Complex