The HSPB8 Knockout NCI-H1975 Polyclonal Cells are a pool of NCI-H1975 cells that have undergone CRISPR/Cas9-mediated disruption of the HSPB8 gene, resulting in a heterogeneous population of knockout cells. This polyclonal knockout product provides a powerful loss-of-function model to dissect HSPB8-dependent cellular processes without the limitations of clonal selection. The targeted gene disruption enables robust and stable ablation of HSPB8 protein expression, offering a versatile system for functional genomics and pathway analysis in a disease-relevant background.
The host cell line, NCI-H1975, is a human lung adenocarcinoma epithelial cell line derived from the pleural effusion of a patient with non-small cell lung cancer (NSCLC). It harbors activating EGFR mutations (L858R/T790M), which drive oncogenic signaling and confer resistance to first- and second-generation EGFR tyrosine kinase inhibitors (TKIs). NCI-H1975 is widely used as a clinically relevant model for studying EGFR-mutant NSCLC, particularly in the context of acquired resistance mechanisms and the development of third-generation inhibitors such as osimertinib.
HSPB8 is a small heat shock protein that functions as a molecular chaperone, directing misfolded and aggregation-prone proteins to autophagic degradation. Its activity is regulated upstream by HSF1 in response to heat shock, oxidative stress, and proteasome inhibition. HSPB8 forms complexes with the co-chaperone BAG3, HSC70/HSP70, and the E3 ubiquitin ligase CHIP/STUB1 to facilitate chaperone-assisted selective autophagy (CASA). It also interacts with 14-3-3 proteins and promotes clearance of ubiquitinated cargoes such as p62/SQSTM1 and LC3-associated aggregates. Additionally, HSPB8 exerts anti-apoptotic effects by binding and inhibiting BAX and JNK, thereby blocking mitochondrial apoptosis and sustaining cell survival under stress. This dual role in protein quality control and apoptosis inhibition positions HSPB8 as a critical node in cellular stress responses.
In the NCI-H1975 NSCLC model, HSPB8 overexpression has been linked to enhanced chemoresistance and tumor cell survival, potentially through its ability to mitigate proteotoxic stress induced by EGFR-TKI treatment and to suppress apoptotic signaling. The polyclonal knockout of HSPB8 in this background allows researchers to dissect the contribution of autophagy, aggrephagy, and stress granule dynamics to drug resistance and tumor progression. By eliminating HSPB8 function without clonal artifacts, this model provides a physiologically relevant system to evaluate the dependency of EGFR-mutant lung cancer cells on chaperone-mediated survival pathways and to identify synergistic vulnerabilities when combined with targeted therapies.
This knockout product enables a range of research applications, including the investigation of HSPB8-mediated autophagy and protein aggregate clearance, analysis of the HSPB8-BAG3-HSC70 axis in chemoresistance, and assessment of apoptosis regulation. Typical assays include western blotting for LC3-II, p62, and cleaved caspase-3; immunofluorescence imaging of ubiquitin/p62 aggresomes; annexin V/PI apoptosis assays; transwell migration/invasion assays; and drug sensitivity testing with osimertinib or other EGFR-TKIs. Co-immunoprecipitation can be used to study HSPB8-containing complexes, while RT-qPCR and proteasome activity assays allow monitoring of stress gene expression and protein degradation pathways. For further details or personalized support, please contact Ascent Research.
