Browsing by Author "Lyssiotis, Costas A."

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    Differential integrated stress response and asparagine production drive symbiosis and therapy resistance of pancreatic adenocarcinoma cells
    (Springer Nature, 2022) Halbrook, Christopher J.; Thurston, Galloway; Boyer, Seth; Anaraki, Cecily; Jiménez, Jennifer A.; McCarthy, Amy; Steele, Nina G.; Kerk, Samuel A.; Hong, Hanna S.; Lin, Lin; Law, Fiona V.; Felton, Catherine; Scipioni, Lorenzo; Sajjakulnukit, Peter; Andren, Anthony; Beutel, Alica K.; Singh, Rima; Nelson, Barbara S.; Van Den Bergh, Fran; Krall, Abigail S.; Mullen, Peter J.; Zhang, Li; Batra, Sandeep; Morton, Jennifer P.; Stanger, Ben Z.; Christofk, Heather R.; Digman, Michelle A.; Beard, Daniel A.; Viale, Andrea; Zhang, Ji; Crawford, Howard C.; di Magliano, Marina Pasca; Jorgensen, Claus; Lyssiotis, Costas A.; Pediatrics, School of Medicine
    The pancreatic tumor microenvironment drives deregulated nutrient availability. Accordingly, pancreatic cancer cells require metabolic adaptations to survive and proliferate. Pancreatic cancer subtypes have been characterized by transcriptional and functional differences, with subtypes reported to exist within the same tumor. However, it remains unclear if this diversity extends to metabolic programming. Here, using metabolomic profiling and functional interrogation of metabolic dependencies, we identify two distinct metabolic subclasses among neoplastic populations within individual human and mouse tumors. Furthermore, these populations are poised for metabolic cross-talk, and in examining this, we find an unexpected role for asparagine supporting proliferation during limited respiration. Constitutive GCN2 activation permits ATF4 signaling in one subtype, driving excess asparagine production. Asparagine release provides resistance during impaired respiration, enabling symbiosis. Functionally, availability of exogenous asparagine during limited respiration indirectly supports maintenance of aspartate pools, a rate-limiting biosynthetic precursor. Conversely, depletion of extracellular asparagine with PEG–asparaginase sensitizes tumors to mitochondrial targeting with phenformin.
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    Mitochondrial Complex II In Intestinal Epithelial Cells Regulates T-cell Mediated Immunopathology
    (Springer Nature, 2021) Fujiwara, Hideaki; Seike, Keisuke; Brooks, Michael D.; Mathew, Anna V.; Kovalenko, Ilya; Pal, Anupama; Lee, Ho-Joon; Peltier, Daniel; Kim, Stephanie; Liu, Chen; Oravecz-Wilson, Katherine; Li, Lu; Sun, Yaping; Byun, Jaeman; Maeda, Yoshinobu; Wicha, Max S.; Saunders, Tom; Rehemtulla, Alnawaz; Lyssiotis, Costas A.; Pennathur, Subramaniam; Reddy, Pavan; Microbiology and Immunology, School of Medicine
    Intestinal epithelial cell (IEC) damage by T cells contributes to graft-versus-host disease (GVHD), inflammatory bowel disease (IBD) and immune checkpoint blockade (ICB) mediated colitis. But little is known about the target cell intrinsic features that influence disease severity. Herein we identified disruption of oxidative phosphorylation and an increase in succinate levels in the IECs from several distinct in vivo models of T cell mediated colitis. Metabolic flux studies, complemented by imaging and protein analyses identified disruption of IEC intrinsic succinate dehydrogenase A (SDHA), a component of mitochondrial complex II, in causing these metabolic alterations. The relevance of IEC intrinsic SDHA in mediating disease severity was confirmed by complementary chemical and genetic experimental approaches and validated in human clinical samples. These data identify a critical role for the alteration of the IEC specific mitochondrial complex II component SDHA in the regulation of the severity of T cell mediated intestinal diseases.