GSS Knockout HT29 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the human HT29 colorectal adenocarcinoma cell line. This polyclonal knockout model has been engineered to disrupt the GSS gene, which encodes glutathione synthetase, the enzyme responsible for the final step of glutathione biosynthesis. The use of a polyclonal population ensures representative genetic heterogeneity, offering a robust loss-of-function model for studying glutathione-dependent processes. The cells are suitable for a range of experimental applications, from basic mechanistic studies to drug screening.
HT29 is a well-characterized human colorectal adenocarcinoma epithelial cell line that serves as a widely used model of intestinal epithelium. These cells retain many features of differentiated intestinal epithelial cells and have been instrumental in studies of nutrient absorption, barrier function, and colorectal cancer biology. The epithelial nature and cancer origin make HT29 particularly relevant for dissecting pathways involved in tumor cell survival, oxidative stress responses, and chemoresistance. By introducing a GSS knockout in this background, researchers can specifically examine how glutathione metabolism influences colorectal cancer cell behavior.
Glutathione synthetase (GSS) catalyzes the ATP-dependent ligation of gamma-glutamylcysteine and glycine to form glutathione, a critical intracellular antioxidant. GSS functions downstream of glutamate-cysteine ligase (GCL), the rate-limiting enzyme in glutathione synthesis, and its activity is transcriptionally regulated by NRF2, AP-1, and NF-??B, which respond to oxidative and electrophilic stress. The primary downstream product, glutathione, serves as a cofactor for glutathione peroxidase 4 (GPX4) and glutathione S-transferases, modulating lipid peroxide detoxification and xenobiotic conjugation. GSS also interacts with GCL and ATP, and its activity directly impacts redox-regulated signaling cascades. Disruption of GSS abolishes de novo glutathione production, thereby impairing the entire glutathione-dependent antioxidant network.
In HT29 colorectal adenocarcinoma cells, knockout of GSS eliminates the major source of glutathione, sensitizing the cells to oxidative stress and ferroptosis, a regulated cell death driven by lipid peroxidation. This model recapitulates key aspects of glutathione synthetase deficiency, a condition characterized by hemolytic anemia and metabolic acidosis, and provides a platform to investigate neurodegenerative and cancer-related redox dysregulation. By rendering the cells dependent on exogenous thiol supply, the knockout also allows interrogation of compensatory pathways and identification of synthetic lethal interactions. The epithelial context is particularly valuable for studying intestinal oxidative injury and the role of glutathione in mucosal defense and carcinogenesis.
This polyclonal knockout cell population is ideally suited for a breadth of functional studies, including glutathione quantification assays to confirm metabolic disruption, western blotting and RT-qPCR for validation of GSS loss, and cell viability measurements under pro-oxidant conditions such as hydrogen peroxide or ferroptosis inducers like erastin. Researchers can employ lipid peroxidation assays and glutathione peroxidase activity tests to gauge ferroptotic sensitivity, while drug sensitivity profiling enables exploration of GSS as a target for overcoming chemoresistance. For further information or to discuss custom applications, please contact Ascent Research.
