PERK-dependent regulation of ceramide synthase 6 and thioredoxin play a key role in mda-7/IL-24-induced killing of primary human glioblastoma multiforme cells.
Melanoma differentiation associated gene-7(mda-7) encodes IL-24, a cytokine that can selectively trigger apoptosis in transformed cells. Recombinant mda-7 adenovirus (Ad.mda-7) effectively kills glioma cells, offering a novel gene therapy strategy to address deadly brain tumors. In this study, we defined the proximal mechanisms by which Ad-mda-7 kills glioma cells. Key factors implicated included activation of the endoplasmic reticulum stress kinase protein kinase R-like endoplasmic reticulum kinase (PERK), Ca(++) elevation, ceramide generation and reactive oxygen species (ROS) production. PERK inhibition blocked ceramide or dihydroceramide generation, which were critical for Ca(++) induction and subsequent ROS formation. Activation of autophagy and cell death relied upon ROS formation, the inhibition of which ablated Ad.mda-7-killing activity. In contrast, inhibiting TRX induced by Ad.MDA-7 enhanced tumor cytotoxicity and improved animal survival in an orthotopic tumor model. Our findings indicate that mda-7/IL-24 induces an endoplasmic reticulum stress response that triggers production of ceramide, Ca(2+), and ROS, which in turn promote glioma cell autophagy and cell death.
Yacoub
Adly
A
Department of Biochemistry and Molecular Biology, VCU Institute of Molecular Medicine, Neurosurgery, Virginia Commonwealth University, School of Medicine, Richmond, Virginia 23298-0035, USA.
Hamed
Hossein A
HA
Allegood
Jeremy
J
Mitchell
Clint
C
Spiegel
Sarah
S
Lesniak
Maciej S
MS
Ogretmen
Besim
B
Dash
Rupesh
R
Sarkar
Devanand
D
Broaddus
William C
WC
Grant
Steven
S
Curiel
David T
DT
Fisher
Paul B
PB
Dent
Paul
P
D000818:Animals; D001343:Autophagy; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002518:Ceramides / Q000378:metabolism; D005909:Glioblastoma / Q000235:genetics / Q000473:pathology / Q000628:therapy; D006801:Humans; D007378:Interleukins / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry; D051379:Mice; D009154:Mutation; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D023041:Xenograft Model Antitumor Assays; D019892:eIF-2 Kinase / Q000235:genetics / Q000378:metabolism*; D000099180:Interleukin-24; D000099156:Superoxide Dismutase 2
D002118:Calcium; D002518:Ceramides; D007378:Interleukins; D010088:Oxidoreductases; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; D013879:Thioredoxins; D019892:eIF-2 Kinase; D000099180:Interleukin-24; D000099156:Superoxide Dismutase 2; C109343:dihydroceramide; C108138:dihydroceramide desaturase