The BAG3 Knockout HT29 Polyclonal Cells constitute a CRISPR/Cas9-edited polyclonal knockout population derived from the HT29 human colorectal adenocarcinoma cell line, with targeted disruption of the BAG3 gene. This loss-of-function model facilitates investigation of BAG3??s role in chaperone-assisted protein quality control, autophagy, and apoptosis. By introducing a stable gene knockout in a polyclonal format, researchers can assess population-level responses without the confounding effects of clonal variation, making it suitable for high-throughput screening and comparative functional studies.
The parental HT29 cell line originates from a primary human colon adenocarcinoma and displays an epithelial morphology characteristic of colorectal tumors. HT29 cells are well-established models for studying colon cancer biology, including drug sensitivity, migration, and signal transduction pathways. They retain key features of colorectal adenocarcinoma, such as constitutive activation of MAPK and NF-??B signaling, and are frequently employed to investigate mechanisms of chemoresistance and autophagy-mediated survival. The epithelial nature of HT29 cells provides a physiologically relevant context for examining BAG3 function in polarized tumor environments.
BAG3 encodes a co-chaperone that acts as a nucleotide exchange factor for Hsp70, facilitating the transfer of misfolded proteins to the autophagy-lysosome pathway. Under proteotoxic stress, BAG3 expression is induced by HSF1, leading to complex formation with Hsp70, HspB8, and the ubiquitin ligase CHIP. BAG3 further interacts with 14-3-3 proteins and Bcl-2 family members, bridging chaperone functions with apoptotic regulation. Through its interaction with p62/SQSTM1, BAG3 promotes selective autophagy, linking the Hsp70/HspB8 chaperone complex to autophagic clearance. Consequently, BAG3 disruption impairs stress-induced autophagy and elevates susceptibility to apoptosis, particularly in tumor cells reliant on proteostasis maintenance.
In HT29 colorectal cancer cells, BAG3 is frequently upregulated and contributes to oncogenic survival by sustaining autophagy and inhibiting apoptosis. Knockout of BAG3 abolishes its Hsp70-regulating activity, disrupting the HSF1?CBAG3?CHsp70/HspB8 axis and impairing autophagic degradation of ubiquitinated proteins. This perturbation sensitizes HT29 cells to chemotherapeutic agents and proteasome inhibitors, highlighting the model??s utility for drug resistance studies. Moreover, the polyclonal knockout pool preserves heterogeneous cellular responses, mirroring the genetic diversity of tumor subpopulations. As a result, this system is particularly valuable for dissecting BAG3-dependent mechanisms in colorectal cancer progression and for evaluating combinatorial therapeutic strategies that target protein quality control pathways.
Typical applications include western blot analysis of BAG3, Hsp70, and LC3-II to monitor autophagy flux; co-immunoprecipitation to assess BAG3-Hsp70 interactions; and immunofluorescence for aggresome formation. Apoptosis assays using Annexin V/PI staining, wound healing migration assays, and chemotherapeutic sensitivity tests are also readily performed with this model. These cells support investigations into colorectal cancer biology, autophagy mechanisms, proteotoxicity, and stress response pathways. Researchers interested in this product are encouraged to contact Ascent Research for further technical details.
