The KDM5A Knockout NCI-H1975 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population featuring targeted genetic disruption of the KDM5A gene in the human NCI-H1975 lung adenocarcinoma cell line. As a polyclonal preparation, this product contains a heterogeneous mix of edited alleles, providing a robust loss-of-function model that avoids single-cell cloning biases and is ideal for population-based studies of chromatin regulation and drug response.
The NCI-H1975 parental line was established from a non-smoking female with lung adenocarcinoma and carries compound EGFR mutations: the activating L858R point mutation and the T790M gatekeeper mutation. These mutations confer dependence on EGFR signaling and are associated with acquired resistance to first-generation tyrosine kinase inhibitors (TKIs). NCI-H1975 is widely used to model TKI resistance, oncogenic signaling, and tumor progression in non-small cell lung cancer.
KDM5A encodes a histone lysine demethylase that erases mono-, di-, and trimethylation at H3K4 (H3K4me1/2/3), thereby repressing transcription. Mechanistically, in the RB pathway, hypophosphorylated retinoblastoma protein (RB) recruits KDM5A to E2F-responsive gene promoters. KDM5A assembles co-repressor complexes containing histone deacetylase 1 (HDAC1) and polycomb repressive complex 2 (PRC2) components, which cooperatively silence cyclin D1 (CCND1), c-Myc (MYC), and other E2F targets. KDM5A is transcriptionally regulated by RB and E2F factors and post-transcriptionally inhibited by miR-137, forming an intricately controlled circuit that modulates cell cycle progression and differentiation.
In NCI-H1975 cells, KDM5A activity may facilitate a drug-tolerant persister phenotype by sustaining a repressive H3K4 methylation landscape at proliferation-associated loci, enabling survival under continuous EGFR TKI exposure. Knockout of KDM5A therefore provides a powerful system to dissect the contribution of histone demethylation to TKI resistance and epithelial-mesenchymal transition (EMT), and to identify synthetic vulnerabilities that could be targeted with epigenetic therapies.
Investigators can employ this polyclonal knockout model in diverse experimental contexts, including quantitative western blotting for H3K4me3 and total H3, ChIP-qPCR at E2F target promoters to assess repressor occupancy, RT-qPCR analysis of CCND1 and MYC expression, and cell proliferation or EGFR inhibitor dose-response assays. Additional applications encompass screening of histone demethylase inhibitors, RNA-sequencing for transcriptome-wide profiling, and evaluation of EMT markers under defined conditions. For further information, please contact Ascent Research.
