The CBX8 Knockout NCI-H1975 Polyclonal Cells product consists of a CRISPR/Cas9-edited polyclonal population of NCI-H1975 human lung adenocarcinoma cells carrying a disrupted CBX8 locus. This heterogeneous knockout pool is designed for loss-of-function studies of CBX8 without clonal selection, enabling researchers to assess polycomb-mediated gene silencing in a genetically relevant non-small cell lung cancer (NSCLC) background. The polyclonal format preserves the genetic diversity of the parental line while eliminating the need for single-cell cloning, thereby reducing potential clonal artifacts in downstream functional assays.
NCI-H1975 is a widely used NSCLC model cell line derived from a lung adenocarcinoma of a non-smoker. It harbors activating mutations in EGFR (L858R/T790M) and PIK3CA, rendering it an established model for studying acquired resistance to EGFR tyrosine kinase inhibitors (TKIs) such as gefitinib and osimertinib. The concurrent presence of these oncogenic drivers makes NCI-H1975 particularly valuable for investigating the interplay between epigenetic regulators and oncogenic signaling in the context of TKI resistance.
CBX8 encodes a chromodomain-containing protein that reads the repressive histone mark H3K27me3. As a core component of PRC1, it interacts with RING1A/B, BMI1 (PCGF4), and PHC1/2/3 to catalyze monoubiquitination of histone H2A, enforcing transcriptional repression of tumor suppressor loci including CDKN2A (p16INK4a), CDKN2B (p15INK4b), HOX genes, PTEN, and DKK1. CBX8 is transcriptionally activated by MYC and E2F factors, and its chromatin recruitment depends on H3K27me3 deposited by the PRC2 complex (EZH2, SUZ12, EED).
In NCI-H1975, CBX8 overexpression contributes to silencing of growth-regulatory genes, driving uncontrolled proliferation and EGFR TKI resistance. Disruption of CBX8 relieves this repression, restoring expression of p16INK4a and p15INK4b and potentially sensitizing cells to TKIs. This polyclonal knockout model enables dissection of epigenetic mechanisms in NSCLC and validation of CBX8 as a therapeutic target.
Researchers can employ these cells in a variety of experimental contexts, including western blotting to confirm loss of CBX8 protein and changes in H3K27me3 or p16 levels; RT?qPCR to monitor derepression of CDKN2A and HOX genes; ChIP?qPCR to assess H3K27me3 occupancy at target loci; cell cycle and apoptosis assays; colony formation analysis; and drug sensitivity profiling with EGFR TKIs. Transcriptomic analysis by RNA?seq can reveal global gene expression changes upon CBX8 disruption. For orders, technical support, or custom gene editing solutions, please contact Ascent Research.
