ABSTRACT
Ferroptosis is a form of cell death that results from the catastrophic accumulation of lipid reactive oxygen species (ROS). Oncogenic signaling elevates lipid ROS production in many tumor types and is counteracted by metabolites that are derived from the amino acid cysteine. In this work, we show that the import of oxidized cysteine (cystine) via system xC - is a critical dependency of pancreatic ductal adenocarcinoma (PDAC), which is a leading cause of cancer mortality. PDAC cells used cysteine to synthesize glutathione and coenzyme A, which, together, down-regulated ferroptosis. Studying genetically engineered mice, we found that the deletion of a system xC - subunit, Slc7a11, induced tumor-selective ferroptosis and inhibited PDAC growth. This was replicated through the administration of cyst(e)inase, a drug that depletes cysteine and cystine, demonstrating a translatable means to induce ferroptosis in PDAC.
Subject(s)
Carcinoma, Pancreatic Ductal/metabolism , Carcinoma, Pancreatic Ductal/pathology , Cysteine/deficiency , Ferroptosis , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/pathology , Animals , Cationic Amino Acid Transporter 1/genetics , Cell Line, Tumor , Cystathionine gamma-Lyase/administration & dosage , Cystathionine gamma-Lyase/pharmacology , Cystine/metabolism , Ferroptosis/drug effects , Ferroptosis/genetics , Gene Deletion , Humans , Mice , Mice, Mutant StrainsABSTRACT
OBJECTIVES: To compare the analysis of different forms of intact albumin in urine from healthy volunteers. To determine contamination by common non-albumin proteins on HPLC analysis of urinary albumin and of purified immuno-unreactive albumin. DESIGN AND METHODS: Overnight urine samples collected from healthy volunteers were analysed for total albumin (immunoreactive plus immuno-unreactive) by HPLC and densitometry following native PAGE separation and for immunoreactive albumin by RIA. The contamination by non-albumin proteins of the HPLC analysis of urinary albumin and of immuno-unreactive albumin preparations was determined by ELISA. Immuno-unreactive albumin was tested for Co2+-binding capacity. RESULTS AND CONCLUSIONS: HPLC analysis of healthy urine generates higher ACR values than immunological methods due to the presence of immuno-unreactive albumin. Immuno-unreactive albumin cannot be accounted for by the non-albumin urinary proteins tested. Isolated immuno-unreactive albumin is not recognised by antibodies to common urinary proteins or by an array of anti-albumin antibodies and behaves like serum albumin in terms of HPLC elution, native PAGE migration, and cobalt ion binding.