title: Inhibition of MEK/ERK1/2 sensitizes lymphoma cells to sorafenib-induced apoptosis.
abstract: Interactions between the multi-kinase inhibitor sorafenib and MEK1/2 inhibitors were investigated in DLBCL cells. Sorafenib (3-10 microM) triggered apoptosis in multiple GC and ABC lymphoma cells. Unexpectedly, sorafenib did not cause sustained ERK1/2 inactivation, and in SUDHL-6 and -16 cells, triggered ERK1/2 activation. Marginally toxic MEK1/2 inhibitor concentrations (5 microM PD184352) abrogated ERK1/2 activation in sorafenib-treated cells and synergistically potentiated apoptosis. MEK1 shRNA transfection also significantly increased sorafenib-mediated lethality. Sorafenib/PD184352 co-administration accelerated Mcl-1 down-regulation without up-regulating Bim(EL). Finally, ectopic Mcl-1 expression attenuated sorafenib/PD184352-mediated apoptosis. Together, these findings provide a theoretical basis for potentiating sorafenib anti-lymphoma activity by MEK1/2 inhibitors.
authors.affiliation: Department of Medicine, Institute of Molecular Medicine and the Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, United States.
authors.forename: Tri K
authors.initials: TK
authors.lastname: Nguyen
authors.forename: Nicholas
authors.initials: N
authors.lastname: Jordan
authors.forename: Jonathan
authors.initials: J
authors.lastname: Friedberg
authors.forename: Richard I
authors.initials: RI
authors.lastname: Fisher
authors.forename: Paul
authors.initials: P
authors.lastname: Dent
authors.forename: Steven
authors.initials: S
authors.lastname: Grant
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001549:Benzamides / Q000008:administration & dosage; D001557:Benzenesulfonates / Q000008:administration & dosage; D015153:Blotting, Western; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors* / Q000187:drug effects; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000378:metabolism*; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors* / Q000187:drug effects; D009536:Niacinamide / Q000031:analogs & derivatives; D010671:Phenylurea Compounds; D011725:Pyridines / Q000008:administration & dosage; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D000077157:Sorafenib; D014162:Transfection
chemical_list: C120227:2-(2-chloro-4-iodophenylamino)-N-cyclopropylmethoxy-3,4-difluorobenzamide; D001549:Benzamides; D001557:Benzenesulfonates; D004791:Enzyme Inhibitors; D010671:Phenylurea Compounds; D011725:Pyridines; D009536:Niacinamide; D000077157:Sorafenib; D048049:Extracellular Signal-Regulated MAP Kinases; D020930:MAP Kinase Kinase Kinases