The DNAJB4 Knockout NCI-H1975 Polyclonal Cells represent a CRISPR/Cas9-mediated polyclonal knockout cell population engineered for loss-of-function studies of the DNAJB4 gene in a human non-small cell lung cancer (NSCLC) background. This product provides a heterogeneous pool of edited cells with disrupted DNAJB4 expression, enabling functional genomics research without clonal isolation artifacts. The gene disruption is achieved through CRISPR/Cas9 technology, generating a mixed population that reflects the biological variability of polyclonal knockout models.
The host cell line, NCI-H1975, is a widely employed model of lung adenocarcinoma derived from a female patient and harbors the activating EGFR L858R and T790M mutations. These mutations confer constitutive kinase activity and resistance to first-generation EGFR tyrosine kinase inhibitors, making NCI-H1975 cells particularly valuable for studying EGFR-driven oncogenesis and resistance mechanisms. The epithelial morphology and established growth characteristics of this cell line support a broad range of biochemical, pharmacological, and functional assays in NSCLC research.
Mechanistically, DNAJB4 (also known as Hsp40 homolog B4) functions as a co-chaperone for the Hsp70 family protein HSPA1A, stimulating its ATPase activity and facilitating protein quality control. As a tumor suppressor, DNAJB4 negatively regulates EGFR signaling by promoting EGFR degradation or inactivation, thereby attenuating downstream effector pathways. In the context of NCI-H1975 cells, DNAJB4 loss relieves suppression of the GRB2?CSOS?CKRAS?CRAF?CMEK?CERK cascade and the AKT1 survival pathway, enhancing phosphorylation of ERK and AKT. Upstream, DNAJB4 transcription is regulated by YY1 and HSF1 in response to proteotoxic stress, while its downstream consequences involve modulation of pro-apoptotic factors such as BAX. DNAJB4 directly interacts with HSPA1A and indirectly influences EGFR stability, positioning it at a critical node between chaperone biology and oncogenic signaling.
In NCI-H1975 cells, which exhibit hyperactive EGFR signaling, the knockout of DNAJB4 is expected to further enhance proliferative and survival pathways, providing a potent model to dissect tumor suppressor functions under constitutive oncogenic pressure. This polyclonal knockout pool is particularly relevant for investigating how chaperone-mediated regulation intersects with mutant EGFR-driven tumorigenesis and drug resistance. Because DNAJB4 expression is frequently downregulated in lung cancers, this loss-of-function system enables the study of its role in maintaining proteostasis and its impact on apoptosis evasion in a clinically relevant NSCLC background.
Research applications include investigating DNAJB4-dependent regulation of EGFR degradation, characterizing altered Hsp70 client protein interactions, and testing for altered sensitivity to EGFR inhibitors. This polyclonal pool is suitable for compound screening to identify modulators of the DNAJB4?CHsp70 axis or synthetic lethal targets. Standard techniques such as Western blotting for EGFR/phospho-ERK, RT-qPCR for DNAJB4, co-immunoprecipitation of HSPA1A, Annexin V flow cytometry, and MTT assays are readily employed. For additional information or custom requests, please contact Ascent Research.
