The GSR Knockout NCI-H1975 Polyclonal Cells are generated by CRISPR/Cas9-mediated gene disruption of GSR in the NCI-H1975 human lung adenocarcinoma cell line. This polyclonal knockout population comprises a heterogeneous mix of edited alleles, providing a population-level representation of GSR deficiency. The model is designed for investigations into redox homeostasis, ferroptosis, and therapeutic resistance.
NCI-H1975 is an epithelial cell line derived from a human lung adenocarcinoma, harboring EGFR L858R and T790M mutations. These dual mutations drive oncogenic signaling and confer acquired resistance to first-generation EGFR tyrosine kinase inhibitors (TKIs), making the cell line a key model for studying EGFR-TKI resistance in NSCLC. The combination of this mutational background with GSR knockout offers a system to explore the interplay between glutathione metabolism and kinase-driven drug resistance.
GSR encodes glutathione reductase, which reduces oxidized glutathione (GSSG) to GSH using NADPH, thereby sustaining the cellular antioxidant pool. Transcription of GSR is regulated by NFE2L2 (NRF2), which is held in check by KEAP1 and stabilized under oxidative stress. Additional inputs come from HIF1A and AP-1. GSH produced by GSR serves as a cofactor for GPX4, a phospholipid hydroperoxidase that prevents ferroptosis. Consequently, GSR activity intersects with both the KEAP1-NRF2-GSR signaling axis and the GSH-GPX4 ferroptosis defense pathway, influencing BCL2 family-mediated apoptosis and lipid peroxidation.
In the NCI-H1975 context, disruption of GSR impairs glutathione recycling, leading to reduced GSH levels and increased ROS. This sensitizes the cells to oxidative insults, including ferroptosis inducers such as erastin. Given that EGFR-mutant lung cancers often exhibit altered redox states and upregulation of antioxidant pathways to resist TKIs, GSR knockout may help circumvent drug resistance. The model thus provides a direct means to study how redox perturbation impacts therapeutic sensitivity in mutant EGFR-driven NSCLC.
Applications include measuring GSH/GSSG ratios, detecting ROS with DCFDA or CellROX, and assessing lipid peroxidation via C11-BODIPY staining. Western blot analysis of GPX4, NRF2, and KEAP1 can dissect ferroptosis-related pathways. Cell viability under H2O2 or erastin treatment, colony formation assays, and EGFR-TKI sensitivity testing are readily performed. The polyclonal population supports robust, unbiased screening of oxidative stress modulators or ferroptosis-targeting compounds. For further details or to request a quote, please contact Ascent Research.
