APTX Knockout HT29 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the HT29 human colorectal adenocarcinoma epithelial cell line. This product enables loss-of-function studies of the APTX gene, which encodes the DNA repair enzyme aprataxin. Using CRISPR/Cas9-mediated gene disruption, the polyclonal cells provide a heterogeneous population with targeted APTX ablation, avoiding clonal selection bias and facilitating robust functional analyses. The model is optimized for investigating DNA single-strand break repair, base excision repair, and cellular responses to oxidative damage in a well-characterized cancer background.
The HT29 host cells were originally isolated from a 44-year-old female patient with colorectal adenocarcinoma. These adherent epithelial cells are widely utilized as a model system for colorectal cancer biology, intestinal epithelial barrier function, and drug absorption and metabolism research. HT29 cells form polarized monolayers and retain differentiated features, making them valuable for studying tumorigenesis, epithelial transport processes, and chemosensitivity. Their extensively documented genetic and phenotypic stability supports reproducible experimental outcomes across various assay platforms.
APTX functions as a DNA deadenylase that specifically removes 5??-adenylate groups from abortive DNA ligation intermediates at single-strand breaks, enabling repair by the XRCC1?CDNA ligase III complex. This activity is critical for protecting nuclear and mitochondrial DNA against oxidative damage. APTX is regulated upstream by ATM and ATR kinases in response to DNA damage sensors and reactive oxygen species (ROS). It directly interacts with XRCC1, DNA ligase III, PARP1, and TDP1, and its loss disrupts repair complex assembly, leading to persistent DNA breaks. Knockout of APTX therefore impairs both single-strand break repair and mitochondrial DNA maintenance, resulting in heightened genomic instability and increased sensitivity to oxidative stress, features central to its role in ataxia with oculomotor apraxia type 1 (AOA1) and neurodegeneration.
In the HT29 colorectal adenocarcinoma context, APTX deletion models the genomic instability and DNA repair deficiencies frequently observed in colorectal carcinogenesis. Colorectal tumors often exhibit elevated ROS levels and defective repair pathways; this knockout accentuates those phenotypes, allowing dissection of how compromised single-strand break repair contributes to replication stress and mutation accumulation in epithelial malignancies. Additionally, the HT29 background enables investigation of how APTX loss influences drug metabolism and chemoresistance, as these cells are commonly used in pharmacological absorption and transport studies. This model bridges DNA repair research with colorectal cancer biology and offers a platform to examine the interplay between oxidative damage and tumor progression.
Researchers can apply APTX Knockout HT29 Polyclonal Cells in a broad range of experimental strategies, including western blotting for protein expression analysis, immunofluorescence detection of ??H2AX foci as a DNA damage marker, comet assays for direct DNA damage quantification, and RT-qPCR for transcript level assessment. Functional studies may involve cell viability and ATP-based assays under hydrogen peroxide-induced oxidative stress, flow cytometry for apoptosis evaluation, and phospho-ATM/ATR signaling analysis. These cells are particularly suited for screening DNA repair inhibitors, modeling molecular aspects of neurodegenerative diseases, and clarifying APTX-dependent mechanisms in colorectal cancer genomic instability. For further information and technical support, please contact Ascent Research.
