CBL Knockout HT29 Polyclonal Cells represent a polyclonal knockout cell population derived from the HT29 human colorectal adenocarcinoma cell line, generated by CRISPR/Cas9-mediated disruption of the CBL gene. This heterogeneous pool of edited cells provides a loss-of-function model to investigate the biological role of CBL in cancer-relevant contexts, without clonal selection or characterization of individual alleles.
The HT29 parental cell line is a widely utilized epithelial model of colorectal adenocarcinoma, characterized by mutant TP53 and a BRAF V600E activating mutation that drives constitutive MEK/ERK signaling. These genetic features make HT29 cells particularly valuable for studying oncogenic pathways, drug resistance, and tumor cell biology.
CBL functions as an E3 ubiquitin-protein ligase that serves as a critical negative regulator of receptor tyrosine kinase (RTK) signaling. Upon growth factor stimulation, such as EGF binding to EGFR, CBL is phosphorylated by SRC family kinases and recruited to activated receptor complexes through interactions with GRB2 and SH3 domain-containing proteins. CBL then mediates ubiquitination of EGFR, targeting it for proteasomal or lysosomal degradation and thereby attenuating downstream RAS/MAPK and PI3K/AKT pathways. CBL also ubiquitinates other RTKs including MET, extending its regulatory influence.
In the HT29 background, where BRAF V600E already strongly activates the MAPK cascade, CBL loss further dysregulates RTK signal termination. The resulting sustained EGFR and MET signaling promotes enhanced phosphorylation of AKT and ERK, contributing to increased proliferation, survival, and potential resistance to EGFR-targeted therapies. This polyclonal knockout model thus provides a unique platform to study the interplay between oncogenic driver mutations and ubiquitin-dependent receptor downregulation.
Applications include biochemical analysis of EGFR ubiquitination and degradation, western blot detection of phospho-EGFR, phospho-AKT, and phospho-ERK, and immunofluorescence monitoring of receptor trafficking. Functional studies such as cell proliferation, colony formation, and drug sensitivity assays with EGFR inhibitors (e.g., gefitinib, cetuximab) can elucidate resistance mechanisms. Flow cytometric cell cycle and apoptosis profiling further define the impact of CBL disruption on cell fate. For further information or technical support, please contact Ascent Research.
