ID3 Knockout HT29 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout population derived from the human colorectal adenocarcinoma HT29 cell line, in which the ID3 gene has been disrupted to abolish its functional expression. This loss-of-function model enables investigation of ID3-dependent regulatory mechanisms in intestinal epithelium and colorectal cancer without bias from clonal selection. The polyclonal composition provides a heterogeneous array of editing outcomes, offering a robust system for functional studies.
The HT29 cell line is a widely used in vitro model originating from a primary colorectal adenocarcinoma. These cells display epithelial morphology and retain intestinal enterocyte characteristics, including differentiation capacity under appropriate conditions. Consequently, HT29 cells are utilized in cancer biology, gastrointestinal physiology, drug screening, and signal transduction research. The epithelial nature of HT29 makes them relevant for examining cell proliferation, differentiation, apoptosis, and barrier function.
At the molecular level, ID3 acts as a dominant-negative inhibitor of bHLH transcription factors by forming non-functional heterodimers with class I bHLH proteins TCF3 (E2A), TCF4 (E2-2), TCF12 (HEB), and additional factors like MYOD1 and SCL/TAL1. This interaction prevents bHLH proteins from binding to E-box DNA sequences and activating target genes, thereby blocking differentiation programs. ID3 expression is induced by multiple signaling cascades: TGF-?? superfamily members (TGF-??, BMP2, BMP4) signal through SMAD1/5/8 and SMAD4 complexes; Notch and Wnt/??-catenin pathways also upregulate ID3. These inputs converge on the ID3 promoter. Downstream, ID3 represses cyclin-dependent kinase inhibitors CDKN1A (p21) and CDKN2B (p15), promoting cell cycle progression and suppressing senescence.
In the context of colorectal adenocarcinoma, ID3 plays a critical role in maintaining the proliferative, undifferentiated state of HT29 cells. Knockout of ID3 disrupts this equilibrium, likely leading to upregulation of bHLH target genes and derepression of CDKN1A and CDKN2B, thereby reducing proliferation and enhancing differentiation. This phenotypic shift makes the ID3 Knockout HT29 Polyclonal Cells a valuable tool for dissecting the molecular basis of colorectal cancer progression, cancer stem cell maintenance, and resistance to chemotherapy. Moreover, the model facilitates analysis of crosstalk between TGF-??, BMP, Notch, and Wnt/??-catenin pathways in intestinal epithelium, which is crucial for understanding tumor heterogeneity and metastatic potential.
These cells are compatible with a wide range of experimental techniques, including transcriptomic profiling by RNA-seq and RT-qPCR, protein analysis via Western blotting, chromatin immunoprecipitation (ChIP-qPCR), and immunofluorescence microscopy. Functional assays such as MTT and BrdU proliferation tests, Annexin V-based apoptosis detection, Transwell migration and invasion assays, and sphere formation studies allow comprehensive phenotypic characterization. The ID3 knockout system is ideal for investigating drug sensitivity, signaling pathway perturbations, and gene regulatory networks in colorectal cancer. For additional technical information or assistance, please contact Ascent Research.
