title: OSU-03012 enhances Ad.7-induced GBM cell killing via ER stress and autophagy and by decreasing expression of mitochondrial protective proteins.
abstract: The present studies focused on determining whether the autophagy-inducing drug OSU-03012 (AR-12) could enhance the toxicity of recombinant adenoviral delivery of melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) in glioblastoma multiforme (GBM) cells. The toxicity of a recombinant adenovirus to express MDA-7/IL-24 (Ad.mda-7) was enhanced by OSU-03012 in a diverse panel of primary human GBM cells. The enhanced toxicity correlated with reduced ERK1/2 phosphorylation and expression of MCL-1 and BCL-XL, and was blocked by molecular activation of ERK1/2 and by inhibition of the intrinsic, but not the extrinsic, apoptosis pathway.  Both OSU-03012 and expression of MDA-7/IL-24 increased phosphorylation of PKR-like endoplasmic reticulum kinase (PERK) that correlated with increased levels of autophagy and expression of dominant negative PERK blocked autophagy induction and tumor cell death. Knockdown of ATG5 or Beclin1 suppressed OSU-03012 enhanced MDA-7/IL-24-induced autophagy and blocked the lethal interaction between the two agents. Ad.mda-7-infected GBM cells secreted MDA-7/IL-24 into the growth media and this conditioned media induced expression of MDA-7/IL-24 in uninfected GBM cells. OSU-03012 interacted with conditioned media to kill GBM cells and knockdown of MDA-7/IL-24 in these cells suppressed tumor cell killing. Collectively, our data demonstrate that the induction of autophagy and mitochondrial dysfunction by a combinatorial treatment approach represents a potentially viable strategy to kill primary human GBM cells.
authors.affiliation: Departments of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, 401 College St., Richmond, VA 23298, USA.
authors.forename: Hossein A
authors.initials: HA
authors.lastname: Hamed
authors.forename: Adly
authors.initials: A
authors.lastname: Yacoub
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Park
authors.forename: Patrick
authors.initials: P
authors.lastname: Eulitt
authors.forename: Devanand
authors.initials: D
authors.lastname: Sarkar
authors.forename: Igor P
authors.initials: IP
authors.lastname: Dimitrie
authors.forename: Ching-Shih
authors.initials: CS
authors.lastname: Chen
authors.forename: Steven
authors.initials: S
authors.lastname: Grant
authors.forename: David T
authors.initials: DT
authors.lastname: Curiel
authors.forename: Paul B
authors.initials: PB
authors.lastname: Fisher
authors.forename: Paul
authors.initials: P
authors.lastname: Dent
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003131:Combined Modality Therapy; D004357:Drug Synergism; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000473:pathology*; D005434:Flow Cytometry; D015316:Genetic Therapy; D005909:Glioblastoma / Q000235:genetics / Q000473:pathology* / Q000628:therapy*; D006801:Humans; D020287:In Situ Nick-End Labeling; D007378:Interleukins / Q000235:genetics; D024101:Mitochondrial Proteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011720:Pyrazoles / Q000627:therapeutic use*; D013449:Sulfonamides / Q000627:therapeutic use*; D019892:eIF-2 Kinase / Q000378:metabolism; D000099180:Interleukin-24
chemical_list: D007378:Interleukins; D024101:Mitochondrial Proteins; D011720:Pyrazoles; D013449:Sulfonamides; D019892:eIF-2 Kinase; D000099180:Interleukin-24; C500894:OSU 03012