HMOX1 Knockout NCI-H1975 Polyclonal Cells comprise a pool of NCI-H1975 lung adenocarcinoma cells with CRISPR/Cas9-mediated disruption of the HMOX1 gene. This polyclonal knockout population offers a heterogeneous HMOX1 loss-of-function model for studying heme oxygenase-1 biology in non-small cell lung cancer (NSCLC) without clonal selection bias.
The NCI-H1975 parental line is a human lung adenocarcinoma model harboring EGFR L858R and T790M mutations. These mutations drive oncogenic signaling and confer resistance to first- and second-generation EGFR tyrosine kinase inhibitors, making the line a standard tool for investigating acquired drug resistance and oxidative stress responses in EGFR-mutant NSCLC.
HMOX1 encodes heme oxygenase-1, the rate-limiting enzyme that degrades pro-oxidant heme into biliverdin, carbon monoxide (CO), and free iron (Fe2+). Biliverdin is reduced to the antioxidant bilirubin by biliverdin reductase; CO activates guanylyl cyclase to produce cGMP, mediating anti-inflammatory and vasodilatory effects; Fe2+ induces ferritin expression to prevent oxidative injury. Transcriptionally, HMOX1 is activated by the KEAP1-NRF2 pathway when oxidative or electrophilic stress disrupts KEAP1-mediated NRF2 degradation. The repressor BACH1 competes with NRF2 at antioxidant response elements. Additional regulators include heme, hypoxia, and IL-10. Consequently, HMOX1 functions as a central node in cellular defense against oxidative stress, iron detoxification, and anti-apoptotic signaling, partly through upregulation of BCL-2 family proteins.
In NCI-H1975 cells, oncogenic EGFR signaling elevates reactive oxygen species, necessitating robust antioxidant responses, including HMOX1 induction. Ablation of HMOX1 may render cells more susceptible to oxidative stress and ferroptosis, a non-apoptotic cell death driven by iron-dependent lipid peroxidation. Given the T790M-mediated resistance to EGFR inhibitors, HMOX1 knockout provides a tool to examine whether the enzyme contributes to drug-tolerant persister states or acquired resistance by blunting oxidative damage and inhibiting ferroptosis. The polyclonal format reflects a range of editing outcomes, allowing functional studies without clonal artifacts.
Researchers can employ heme oxygenase activity assays, ROS detection, ferroptosis induction, cell viability measurements, and migration studies to analyze HMOX1 function in EGFR inhibitor sensitivity and resistance. Expression profiling by RT-qPCR and western blotting complements functional assays. This polyclonal knockout model supports investigation of cytoprotective signaling, iron-dependent cell death, and redox modulation in NSCLC. For ordering and technical inquiries, contact Ascent Research.
