The DNAJB4 Knockout NCI-H1299 Polyclonal Cells represent a CRISPR/Cas9-edited polyclonal knockout cell population in which the DNAJB4 gene has been disrupted to create a loss-of-function model. This product comprises a heterogeneous mixture of NCI-H1299 cells carrying diverse edits at the DNAJB4 locus, providing a robust tool for studying gene function without the clonal biases of single-cell-derived lines. The polyclonal format preserves the genetic diversity inherent to the editing process, making it suitable for pooled functional screens and assays requiring representation of multiple knockout alleles. Researchers can utilize this model to investigate DNAJB4-dependent mechanisms in a lung cancer context with high experimental reproducibility.
The NCI-H1299 host cell line is a widely used model of non-small cell lung carcinoma (NSCLC) derived from a lymph node metastasis of a human male patient. These adherent cells exhibit an epithelial morphology and harbor a homozygous deletion of the TP53 gene, rendering them p53-null and providing a background sensitized to oncogenic signaling. NCI-H1299 cells are frequently employed in cancer biology studies focusing on tumor suppression, drug resistance, and metastatic potential, particularly in the context of EGFR-driven pathways. Their well-characterized genotype and phenotypic stability make them an ideal platform for dissecting the roles of candidate tumor suppressors like DNAJB4.
DNAJB4 encodes a member of the Hsp40 co-chaperone family that stimulates Hsp70 ATPase activity to facilitate protein folding and degradation. Mechanistically, DNAJB4 functions as a tumor suppressor by promoting ubiquitination and degradation of the epidermal growth factor receptor (EGFR), thereby attenuating downstream MEK/ERK and PI3K/AKT signaling. It also interacts directly with STAT3 to inhibit its transcriptional activity, leading to reduced expression of pro-proliferative and anti-apoptotic target genes. Key interacting factors include HSPA1A/HSPA1B, BAG3, STUB1/CHIP, and HSP90. The DNAJB4 regulatory network is influenced by upstream activators such as HSF1 and FOXO3, while epigenetic silencing through promoter methylation by DNMTs often diminishes its expression in tumors. Downstream, loss of DNAJB4 results in sustained phosphorylation of ERK1/2, AKT, and STAT3, thereby promoting cell proliferation, migration, and survival.
In the NCI-H1299 cellular context, knockout of DNAJB4 exacerbates the tumorigenic phenotype driven by EGFR and STAT3 pathway activation. Because these cells already lack p53, the additional removal of DNAJB4??s growth-suppressive functions provides a powerful model to study cooperative oncogenic mechanisms and resistance to EGFR-targeted therapies. The combined disruption enables researchers to dissect how chaperone-mediated degradation of oncoproteins intersects with apoptotic and migratory programs. This knockout model is particularly relevant for investigating mechanisms of gefitinib resistance and for identifying synthetic lethal interactions that could inform therapeutic strategies in NSCLC.
Typical research applications include functional validation of DNAJB4??s role in EGFR and STAT3 signaling crosstalk, high-throughput screening for compounds that restore DNAJB4 expression or mimic its activity, and drug sensitivity assays with EGFR inhibitors such as gefitinib. The polyclonal cell pool is well-suited for xenograft tumorigenesis studies to evaluate metastatic potential in vivo, as well as for co-immunoprecipitation experiments to map protein interaction networks involving DNAJB4, HSP70, and EGFR. Additional assays like Annexin V apoptosis profiling, transwell migration and invasion tests, and colony formation assays can be routinely performed to quantify phenotypic changes. For further technical details or customized support, please contact Ascent Research.
