The GSTZ1 Knockout NCI-H1975 Polyclonal Cells product comprises a CRISPR/Cas9-edited polyclonal population of NCI-H1975 cells with targeted disruption of the GSTZ1 gene. This pooled knockout model provides a heterogeneous loss-of-function system suitable for phenotypic screening, metabolic studies, and drug response assays in a lung adenocarcinoma background.
NCI-H1975 is a human non-small cell lung cancer (NSCLC) cell line derived from a non-smoking female patient. It harbors activating EGFR L858R and T790M mutations, along with a PIK3CA mutation, making it a well-established model for investigating mechanisms of EGFR-targeted therapy resistance and tumor progression. The epithelial origin and defined genetic lesions offer a clinically relevant context for exploring metabolic vulnerabilities in drug-resistant NSCLC.
GSTZ1 encodes maleylacetoacetate isomerase, a glutathione-dependent enzyme that catalyzes the isomerization of maleylacetoacetate to fumarylacetoacetate in the terminal steps of phenylalanine and tyrosine catabolism. Additionally, it dechlorinates dichloroacetate to glyoxylate and possesses glutathione peroxidase activity toward lipid hydroperoxides. Within the metabolic cascade, GSTZ1 functions downstream of HPD (4-hydroxyphenylpyruvate dioxygenase) and upstream of FAH (fumarylacetoacetate hydrolase), directly converting maleylacetoacetate and generating substrates for fumarate and acetoacetate production. Its expression is regulated by transcription factors such as NRF2, AHR, and PPAR??, integrating signals from oxidative stress and xenobiotic metabolism. Knockout of GSTZ1 disrupts these pathways, leading to accumulation of maleylacetoacetate, altered GSH/GSSG ratios, and elevated ROS levels.
In the context of NCI-H1975 cells, GSTZ1 knockout creates a valuable model for studying metabolic enzyme deficiency in the presence of oncogenic EGFR and PIK3CA signaling. The loss of enzyme activity impairs detoxification and amino acid catabolism, potentially sensitizing cells to metabolic stress and altering the response to EGFR inhibitors. Accumulated phenylalanine/tyrosine intermediates and redox imbalance may influence cell survival, providing a platform to dissect how metabolic reprogramming contributes to drug resistance. This polyclonal knockout pool enables robust assessment of GSTZ1-dependent phenotypes without the bias of clonal selection.
Research applications include metabolomic analysis of phenylalanine/tyrosine pathways, investigation of GSTZ1??s role in drug resistance, and evaluation of dichloroacetate toxicity. Standard characterization techniques involve Western blotting and RT-qPCR for confirmation, enzyme activity assays using maleylacetoacetate or dichloroacetate, and LC-MS-based metabolite profiling to quantify intermediates such as maleylacetoacetate, fumarate, and glyoxylate. Functional studies encompass viability, proliferation, and migration assays under treatment with EGFR inhibitors or dichloroacetate. Redox status can be monitored through glutathione and ROS measurements. For further information, please contact Ascent Research.
