The EIF4G3 Knockout NCI-H1975 Polyclonal Cells product is a CRISPR/Cas9-edited polyclonal knockout cell population targeting the human EIF4G3 gene in the NCI-H1975 non-small cell lung cancer (NSCLC) cell line. This heterogeneous pool of gene-disrupted cells eliminates the need for single-cell cloning, thereby preserving the natural population dynamics and minimizing artifacts associated with clonal selection. It provides a robust loss-of-function model to investigate the biological consequences of EIF4G3 ablation in an oncogenic context.
The NCI-H1975 cell line, derived from the pleural effusion of a non-smoking female with adenocarcinoma, is a well-characterized model of EGFR-mutant NSCLC. It harbors the L858R activating mutation and the T790M gatekeeper mutation, which together drive constitutive kinase activity and confer resistance to first-generation EGFR tyrosine kinase inhibitors. Consequently, NCI-H1975 cells are widely used to study acquired drug resistance mechanisms, and they rely heavily on cap-dependent translation to sustain the synthesis of oncogenic drivers.
EIF4G3 encodes a large scaffold protein that serves as the backbone of the eIF4F translation initiation complex. It directly interacts with the cap-binding protein eIF4E and the RNA helicase eIF4A to bridge the mRNA 5?? cap and the 43S preinitiation complex, enabling ribosomal scanning. The activity of EIF4G3 is primarily regulated by mTORC1: when active, mTOR phosphorylates 4E-BP1, releasing eIF4E to bind EIF4G3 and form the active eIF4F complex. EIF4G3 also interacts with PABPC1, facilitating mRNA circularization, and recruits MNK1 to phosphorylate eIF4E. Downstream, EIF4G3 integrates signals from PI3K/AKT/mTOR and MAPK pathways to enhance translation of oncogenic mRNAs such as MYC, CCND1, and survivin.
In the context of NCI-H1975 cells, oncogenic EGFR signaling hyperactivates the mTORC1 pathway, leading to increased eIF4F complex formation and elevated translation of malignancy-associated transcripts. Disruption of EIF4G3 is predicted to impair the assembly of the eIF4F complex, thereby reducing the protein synthesis of key oncogenic drivers and anti-apoptotic factors. This knockout model may consequently reveal vulnerabilities in translation-dependent growth and survival, sensitizing cells to EGFR inhibition and providing insights into resistance mechanisms. The polyclonal nature of the knockout population ensures that observed phenotypes are representative of the pooled genetic editing, avoiding clonal drift and enabling robust translatomic and functional studies.
Researchers can utilize this EIF4G3 knockout polyclonal cell population for a variety of downstream applications. Common assays include western blotting to confirm EIF4G3 depletion and assess downstream targets such as MYC and CCND1, polysome profiling to evaluate global translation efficiency, and cap-binding assays to quantify eIF4F complex integrity. Viability assays (e.g., MTT) and colony formation tests can measure cell proliferation and drug sensitivity, while RNA sequencing and ribosome profiling enable comprehensive translatomic analysis. For additional information, technical assistance, or custom orders, please contact Ascent Research.
