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Supplementary Figures 1-11 from PERK–Dependent Regulation of Ceramide Synthase 6 and Thioredoxin Play a Key Role in <i>mda</i>-7/IL-24–Induced Killing of Primary Human Glioblastoma Multiforme Cells

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posted on 2023-03-30, 19:43 authored by Adly Yacoub, Hossein A. Hamed, Jeremy Allegood, Clint Mitchell, Sarah Spiegel, Maciej S. Lesniak, Besim Ogretmen, Rupesh Dash, Devanand Sarkar, William C. Broaddus, Steven Grant, David T. Curiel, Paul B. Fisher, Paul Dent
Supplementary Figures 1-11 from PERK–Dependent Regulation of Ceramide Synthase 6 and Thioredoxin Play a Key Role in <i>mda</i>-7/IL-24–Induced Killing of Primary Human Glioblastoma Multiforme Cells

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ARTICLE ABSTRACT

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, Ca2+, and ROS, which in turn promote glioma cell autophagy and cell death. Cancer Res; 70(3); 1120–9