The DNAJB4 Knockout SK-HEP-1 Polyclonal Cells product is a CRISPR/Cas9-edited polyclonal knockout cell population derived from the SK-HEP-1 human hepatocellular carcinoma cell line. This model features targeted disruption of the DNAJB4 gene, which encodes an HSP40 co-chaperone, providing a loss-of-function tool for investigating proteostasis and stress signaling in liver cancer biology. The polyclonal format reflects a heterogenous edited population, avoiding the limitations of single-cell clonal selection while retaining functional gene ablation suitable for population-level assays.
SK-HEP-1 is a well-characterized cell line originally isolated from the ascites of a male patient with liver adenocarcinoma. It is widely employed as a model for hepatocellular carcinoma (HCC) and metastatic liver cancer, exhibiting endothelial-like and mesenchymal features. The line??s robust growth and responsiveness to stress stimuli make it an ideal host for studying the impact of DNAJB4 disruption on tumor cell behavior, particularly in the context of the unfolded protein response (UPR) and endoplasmic reticulum (ER) stress pathways.
DNAJB4 belongs to the DNAJ/HSP40 family and functions as a co-chaperone that stimulates the ATPase activity of HSP70 chaperones, thereby facilitating protein folding, translocation, and degradation. It interacts directly with HSPA1A/HSP70 and HSPA8/HSC70, and cooperates with BAG3 and the E3 ubiquitin ligase STUB1/CHIP to promote clearance of misfolded proteins. Upstream regulators include heat shock factor 1 (HSF1), ER stress sensors ATF6 and IRE1??, and pharmacological ER stress inducers such as tunicamycin and thapsigargin. Through these interactions, DNAJB4 modulates key signaling branches including the MAPK/ERK pathway and ER stress-induced apoptosis, acting downstream of PERK and IRE1?? and transcriptionally influencing UPR effectors like CHOP and GRP78/BiP.
Knockout of DNAJB4 in SK-HEP-1 cells disrupts cellular protein homeostasis, impairing the adaptive UPR and sensitizing cells to ER stress-induced apoptosis. Given the proposed tumor suppressor role of DNAJB4 in HCC, this knockout model may exhibit enhanced proliferative capacity, altered migration, and resistance to proteotoxic stress. It enables dissection of how co-chaperone networks intersect with oncogenic signaling in liver cancer and how loss of DNAJB4 impacts HSP70-dependent pathways critical for tumor cell survival under adverse microenvironments.
This tool is suited for applications such as evaluating UPR activation via western blotting of GRP78, CHOP, and HSP70, quantifying DNAJB4 and UPR target gene expression by RT-qPCR, and measuring apoptosis by Annexin V/propidium iodide flow cytometry under ER stress induced by tunicamycin treatment. Researchers can also perform co-immunoprecipitation to assess HSP70 complex integrity and transwell migration/invasion assays to probe metastatic potential. These approaches support drug sensitivity screening and mechanistic studies of proteostasis in liver cancer. For further information, please contact Ascent Research.
