OSU-03012 stimulates PKR-like endoplasmic reticulum-dependent increases in 70-kDa heat shock protein expression, attenuating its lethal actions in transformed cells.
We have further defined mechanism(s) by which 2-amino-N-{4-[5-(2-phenanthrenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]-phenyl}acetamide [OSU-03012 (OSU)], a derivative of the cyclooxygenase-2 (COX2) inhibitor celecoxib but lacking COX2 inhibitory activity, kills transformed cells. In cells lacking expression of protein kinase R-like endoplasmic reticulum kinase (PERK(-/-)), the lethality of OSU was attenuated. OSU enhanced the expression of Beclin 1 and ATG5 and cleavage of pro-caspase 4 in a PERK-dependent fashion and promoted the Beclin 1- and ATG5-dependent formation of vacuoles containing LC3, followed by a subsequent caspase 4-dependent cleavage of cathepsin B and a cathepsin B-dependent formation of low pH intracellular vesicles; cathepsin B was activated and released into the cytosol and genetic suppression of caspase 4, cathepsin B, or apoptosis-inducing factor function significantly suppressed cell killing. In parallel, OSU caused PERK-dependent increases in 70-kDa heat shock protein (HSP70) expression and decreases in 90-kDa heat shock protein (HSP90) and Grp78/BiP expression. Changes in HSP70 expression were post-transcriptional. Knock-down or small-molecule inhibition of HSP70 expression enhanced OSU toxicity, and overexpression of HSP70 suppressed OSU-induced low pH vesicle formation and lethality. Our data demonstrate that OSU-03012 causes cell killing that is dependent on PERK-induced activation of multiple toxic proteases. OSU-03012 also increased expression of HSP70 in a PERK-dependent fashion, providing support for the contention that OSU-03012-induced PERK signaling promotes both cell survival and cell death processes.
Park
Margaret A
MA
Department of Biochemistry, 401 College Street, Massey Cancer Center, Room 280a, Box 980035, Virginia Commonwealth University, Richmond, VA 23298-0035, USA.
Yacoub
Adly
A
Rahmani
Mohammed
M
Zhang
Guo
G
Hart
Lori
L
Hagan
Michael P
MP
Calderwood
Stuart K
SK
Sherman
Michael Y
MY
Koumenis
Costas
C
Spiegel
Sarah
S
Chen
Ching-Shih
CS
Graf
Martin
M
Curiel
David T
DT
Fisher
Paul B
PB
Grant
Steven
S
Dent
Paul
P
D000818:Animals; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D053471:Caspases, Initiator / Q000378:metabolism; D002401:Cathepsin B / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000187:drug effects* / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D011992:Endosomes / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D005799:Genes, Dominant; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D008970:Molecular Weight; D011720:Pyrazoles / Q000494:pharmacology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology*; D022161:Transport Vesicles / Q000187:drug effects / Q000378:metabolism; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism; D019892:eIF-2 Kinase / Q000172:deficiency / Q000378:metabolism*
D051033:Apoptosis Inducing Factor; D053471:Caspases, Initiator; D002401:Cathepsin B; D000091342:Endoplasmic Reticulum Chaperone BiP; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D008869:Microtubule-Associated Proteins; D018832:Molecular Chaperones; D011720:Pyrazoles; D011993:Recombinant Fusion Proteins; D013449:Sulfonamides; D019892:eIF-2 Kinase; C000717247:HSPA5 protein, human; C000717248:Hspa5 protein, mouse; C500894:OSU 03012; C093516:CASP4 protein, human