The HDAC inhibitor AR42 interacts with pazopanib to kill trametinib/dabrafenib-resistant melanoma cells in vitro and in vivo.
Studies focused on the killing of activated B-RAF melanoma cells by the histone deacetylase (HDAC) inhibitor AR42. Compared to other tumor cell lines, PDX melanoma isolates were significantly more sensitive to AR42-induced killing. AR42 and the multi-kinase inhibitor pazopanib interacted to activate: an eIF2α-Beclin1 pathway causing autophagosome formation; an eIF2α-DR4/DR5/CD95 pathway; and an eIF2α-dependent reduction in the expression of c-FLIP-s, MCL-1 and BCL-XL. AR42 did not alter basal chaperone activity but increased the ability of pazopanib to inhibit HSP90, HSP70 and GRP78. AR42 and pazopanib caused HSP90/HSP70 dissociation from RAF-1 and B-RAF that resulted in reduced 'RAF' expression. The drug combination activated a DNA-damage-ATM-AMPK pathway that was associated with: NFκB activation; reduced mTOR S2448 and ULK-1 S757 phosphorylation; and increased ULK-1 S317 and ATG13 S318 phosphorylation. Knock down of PERK, eIF2α, Beclin1, ATG5 or AMPKα, or expression of IκB S32A S36A, ca-mTOR or TRX, reduced cell killing. AR42, via lysosomal degradation, reduced the protein expression of HDACs 2/5/6/10/11. In vivo, a 3-day exposure of dabrafenib/trametinib resistant melanoma cells to the AR42 pazopanib combination reduced tumor growth and enhanced survival from ~25 to ~40 days. Tumor cells that had adapted through therapy exhibited elevated HGF expression and the c-MET inhibitor crizotinib enhanced AR42 pazopanib lethality in this evolved drug-resistant population.
Departments of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA.
Laurence
L
Booth
Departments of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA.
Jane L
JL
Roberts
University of Pittsburgh Cancer Institute Melanoma and Skin Cancer Program, Hillman Cancer Research Pavilion Laboratory L1.32c, Pittsburgh PA 15232, USA.
Cindy
C
Sander
Chan Soon-Shiong Institute of Molecular Medicine, Culver City, CA 90232, USA.
John
J
Lee
University of Pittsburgh Cancer Institute Melanoma and Skin Cancer Program, Hillman Cancer Research Pavilion Laboratory L1.32c, Pittsburgh PA 15232, USA.
John M
JM
Kirkwood
Department of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA.
Andrew
A
Poklepovic
Departments of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298, USA.
Paul
P
Dent
D020533:Angiogenesis Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D000071182:Autophagosomes / Q000187:drug effects / Q000378:metabolism; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004357:Drug Synergism; D000091342:Endoplasmic Reticulum Chaperone BiP; D015852:Eukaryotic Initiation Factor-2 / Q000235:genetics / Q000378:metabolism; D000073864:Histone Deacetylase 6; D056572:Histone Deacetylase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D007191:Indazoles; D053208:Kaplan-Meier Estimate; D008297:Male; D008545:Melanoma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D010091:Oximes / Q000494:pharmacology*; D010654:Phenylbutyrates / Q000008:administration & dosage / Q000494:pharmacology*; D011728:Pyridones / Q000494:pharmacology*; D011743:Pyrimidines / Q000008:administration & dosage / Q000494:pharmacology*; D011744:Pyrimidinones / Q000494:pharmacology*; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013449:Sulfonamides / Q000008:administration & dosage / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
D020533:Angiogenesis Inhibitors; D000091342:Endoplasmic Reticulum Chaperone BiP; D015852:Eukaryotic Initiation Factor-2; C000717247:HSPA5 protein, human; D056572:Histone Deacetylase Inhibitors; C000717248:Hspa5 protein, mouse; D007093:Imidazoles; D007191:Indazoles; C529674:OSU-HDAC42 compound; D010091:Oximes; D010654:Phenylbutyrates; D011728:Pyridones; D011743:Pyrimidines; D011744:Pyrimidinones; D013449:Sulfonamides; C560077:trametinib; C516667:pazopanib; C433811:HDAC6 protein, human; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases; C561627:dabrafenib
ER stress; autophagy; chaperone; death receptor